Dressing

for Altitude

U.S. Aviation Pressure Suits–Wiley Post to Space Shuttle

Dennis R. Jenkins
DRESSING FOR ALTITUDE

U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle
Copyright © 2012 by the National Aeronautics and Space Administration

The opinions expressed in this volume are those of the authors and do not 

necessarily reflect the official positions of the United States Government or of the 

National Aeronautics and Space Administration.

F as ro el t yb eh S epu ir tn e edn tn fo D co mu e tn G .S.U ,s evo r emn tn P ir itn O gn eciff

I tn re en :t tskoob ro e enohP vog.opg. : lot l f eer ( ;0081-215 )668 D C a er ( a 0081-215 )202

aF :x ( aM 4012-215 )202 :li I potS CCD W , ihsa notgn D , C 1000-20402 

ISBN 978-0-16-090110-2

9 780160 901102

90000

ISBN 978-0-16-090110-2
DRESSING FOR ALTITUDE

U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle

Dennis R. Jenkins

National Aeronautics and Space Administration

Headquarters

300 E Street SW

Washington, DC 20546

NASA SP-2011-595
Library of Congress Cataloging-in-Publication Data

Jenkins, Dennis R.

 Dressing for altitude : U.S. aviation pressure suits-- Wiley Post to space

shuttle / Dennis R. Jenkins.

 p. cm. -- (NASA SP ; 2011-595)

ISBN 978-0-16-090110-2

1. Pressure suits--United States. 2. Space suits--United States. I.

Title.

 TL697.P7J46 2012

 629.134'43--dc23 

 2012004448
i

Table of Contents

iii NASA

v Foreword

vii Jack Bassick Biography

ix Preface

xii Acknowledgments 

xiii Dedication

15 1: Introduction

15 Horror Vacui

18 Structure of the Atmosphere

20 Atmospheric Pressure

22 Physiological Issues of HighAltitude Flight

25 2: Mark Ridge, Wiley Post, 

and John Kearby

25 Early Pressure Suits

28 Wiley Post and the Winnie Mae

35 International Efforts

41 Aeromedical Pioneers 

43 The U.S. Army Rediscovers the 

Pressure Suit

69 Summary

71 3: Acceleration Protection

72 The Physiology of Acceleration

74 Human Centrifuges

80 The Beginning of an Idea

83 Australian Cotton 

Aerodynamic Anti-G Suit

86 Canadian Franks Flying Suit

89 The Americans

92 Berger Brothers

96 The Worcester Connection

105 Cutaway Suits

109 Postwar Suits

110 TLSS and COMBAT EDGE

116 ATAGS and the F-22

118 Rediscovering the Progressive 

Arterial Occlusion Suit

119 Summary

121 4: Partial-Pressure Suits

121 Pressure Breathing

125 S-1—Genesis of the Partial-Pressure 

Suit

135 S-2 and T-1—Production PartialPressure Suits

141 MC-1—Featherweight Suit

146 MB-1 and MB-2—Ill-Fated Air 

Defense Command Suits

147 MC-3 and MC-4—Dragon Ladies 

and Hustlers 

161 MC-3A Specials—Manhigh, 

Excelsior, and Stargazer 

165 CSU-2/P—Attempt to Improve 

the MC-4 

167 C-1A and C-4—Navy Capstan Suits

168 CSU-4/P and CSU-5/P—Bladders 

Only

173 HAPS—NASA Dryden HighAltitude Protective System

179 5: Navy Full-Pressure Suits

215 Russell Colley, Again

218 Mark I

220 Mark II

222 Mark III

227 Mark IV 

231 Mark IV Suits for Strato-Lab

233 Mark V

233 Project Mercury Spacesuits

237 6: Air Force Full-Pressure Suits

241 Lines of Nonextension

243 MC-2—A New Beginning 

262 A/P22S-2—Production USAF 

Full-Pressure Suits

264 Sidebar: The Evolving Pressure Suit 

Depot

279 A/P22S-3—A Navy Suit for the 

Air Force

283 A/P22S-4 and A/P22S-6—Evolving 

the Concept 

293 Boyle's Law Suit

295 PHAFO—The StillBorn 

High-Altitude Flying Outfit 

301 7: Special Project Suits

301 S901 and S970—Suits for Oxcart

316 S-100—Hybrid Suit for the 

Original U-2

322 S901J—Initial Suit for Senior Crown

334 S1010—A Suit for the Dragon Lady

339 S1030—Improved Senior Crown Suits 

348 S1031—Improved Dragon Lady Suits 

349 S1031C—Common Suit

350 S1034—Improved Common Suit

362 Sidebar: The Shrinking Industrial Base

365 8: Space Shuttle Pressure Suits

366 ISSA and EIS—Stillborn Space Shuttle 

Suits 

374 S1030A—Ejection Escape System 

(EES) Suits 

378 LEH—Launch Entry Helmet 

382 S1032—Launch Entry Suits (LES)

399 S1035—Advanced Crew Escape Suit 

(ACES)

410 Comparing Columbia to an 

SR-71 Breakup

413 Endnotes

471 Index

Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins
NaSa
iii

NASA

Since its earliest days, flight has been about 

pushing the limits of technology and, in many 

cases, pushing the limits of human endurance. 

The human body can be the limiting factor in 

the design of aircraft and spacecraft. Humans 

cannot survive unaided at high altitudes. 

There have been a number of books written 

on the subject of spacesuits, but the literature 

on the high-altitude pressure suits is lacking. 

This volume provides a high-level summary 

of the technological development and operational use of partial- and full-pressure suits, 

from the earliest models to the current highaltitude, full-pressure suits used for modern 

aviation, as well as those that were used for 

launch and entry on the Space Shuttle. The 

goal of this work is to provide a resource on 

the technology for suits designed to keep 

humans alive at the edge of space. Hopefully, 

future generations will learn from the hardfought lessons of the past.

NASA is committed to the future of 

aerospace, and a key component of that 

future is the workforce. Without these men 

and women, technological advancements 

would not be possible. Dressing for Altitude 

is designed to provide the history of the 

technology and to explore the lessons learned 

through years of research in creating, testing, 

and utilizing today’s high-altitude suits. It 

is our hope that this information will prove 

helpful in the development of future suits. 

Even with the closeout of the Space Shuttle 

and the planned ending of the U-2 program, 

pressure suits will be needed for protection as 

long as humans seek to explore high frontiers.

The NASA Aeronautics Research Mission 

Directorate is committed to the training of 

the current and future aerospace workforce. 

This book and the other books published 

by the NASA Aeronautics Research Mission 

Directorate are in support of this commitment. Hopefully, you will find this book a 

valuable resource for many years to come.

Tony Springer

Lead, Communications and Education

NASA Aeronautics Research Mission Directorate
iv

Foreword
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

v

Foreword

Foreword

The definitive story of pressure suits began 

long ago and has involved a great many people 

to obtain the present state of the art as this 

book well chronicles. Many of these people 

were visionaries who anticipated the need for 

such highly specialized equipment long before 

it could actually be employed in any practical 

application. A remarkable number of pressure 

suit designs were developed early on, the vast 

majority of which never made it into flight, 

amounting to little more than science projects. 

Nonetheless, these early “experiments” 

informed later work, which led to practical 

pressure suits when they were needed for highaltitude flight.

All successful pressure suit designs have 

been the result of efforts to address a specific 

need in a specific application, beginning 

with Wiley Post’s pressure suit designed for 

use in his Lockheed Vega, the Winnie Mae. 

Long considered the granddaddy of modern 

pressure suits, interestingly, Post’s suit was 

employed principally for protection from 

hypoxia rather than decompression sickness, 

since his Lockheed Vega’s altitude ceiling was 

50,000 feet.

A key ingredient to successful pressure suit 

programs has been the close collaboration 

between vehicle designers, pressure suit 

designers, and, most importantly, the aircrews 

themselves. Given that pressure suits are of 

necessity, totally encompassing, the importance 

of satisfying all human factors cannot be 

overstated. Just how effectively pioneering 

suit designers dealt with human factors is 

perhaps best illustrated by the fact that the 

first practical pressure suit design developed 

for high-attitude flight above 50,000 feet 

(the capstan-operated partial pressure suit 

first employed in the X-1 rocket plane in the 

late 1940s) was subsequently employed in 

untold numbers of aircraft all over the world, 

remaining in service until 1989 when the last 

Lockheed U-2C aircraft was retired. 

The snug-fitting, conformal nature of the 

capstan partial pressure suit necessitated a 

very close working relationship between suit 

designers and aircrews, thus fostering an 

ongoing awareness of human factors and their 

importance. This awareness became most 

acute with the advent of the U-2 program, 

wherein pilots were required to fly well above 

50,000 feet, wearing their capstan partial 

pressure suits for extended periods of time, 

often experiencing cabin decompressions, 

which necessitated that they continue flying 

in their pressurized suit. Thus began a 

concerted effort to make continuous pressure 

suit improvements as materials, processes, 

and technologies allowed, so as to maximize 

functionality and minimize suit-induced stress 

and fatigue on the pilot to the extent possible.

The first operational full-pressure suit 

employed (in the D-558-2 Douglas Skyrocket) for flight above 50,000 feet was also 

the result of a collaboration between suit 

designers and the pilot (Scott Crossfield). 

This close collaboration continued on for the 

development of the landmark full-pressure 

suit for the X-15 program. The X-15 suit first 

employed link-net material, originally conceived for the neck section of early U-2 pilot 

helmets to aid pressurized mobility, for the 

entire restraint layer of the suit. This unique 

material greatly facilitated custom suit fitting 

and enhanced pilot comfort and remains in 

use to the present. Thus, the X-15 suit is really 

the granddaddy of modern-day pressure suits, 
vi

Foreword

as it led directly to the standardized military 

full-pressure suits that followed and continue 

in service to the present. Further, the X-15’s 

high performance required that the pressure 

suit be capable of withstanding exposure to 

extreme altitudes, temperatures, and high-Q 

ejections, thus setting the stage to satisfy similar requirements for later programs, namely 

the A-12, SR-71, XB-70, and Space Shuttle.

The development of a versatile thru-helmet 

feeding and drinking system and a reliable 

urine collection system in the late 1960s further 

enhanced pilot comfort and performance. 

Two later innovations aimed at reducing pilot 

stress and fatigue were the development of a 

non-conformal, full-pressure helmet with a 

moveable visor and breathable gas containers, 

both of which were originally developed for 

the U-2 program but were quickly adopted by 

NASA for the Space Shuttle.

From the dawn of high-altitude flight, the 

cadre of people specializing in crew protection 

for this extreme regime has remained relatively 

small and, consequently, cross fertilization 

of knowledge amongst the different programs 

and disciplines was (fortunately) inevitable. 

Thus, today’s advanced state of the art for 

pressure suits is the result of many people’s 

dedicated work in government, industry, and 

even academia. However, one program, in 

particular, stands out for advancing the state of 

the art of pressure suits over the past 56 years, 

the U-2 program. From the beginning in 1955, 

the U-2 program’s enlightened management 

has remained ever supportive of advancements 

in pilot’s protective equipment when/wherever 

possible. At present, the U-2 program husbands 

the sole remaining national high-altitude pilot 

protection capability.

The future of pressure suits remains to be seen; 

however, it is reasonably certain that man 

will continue to fly high and fast, and since 

he must wear something, it would seem 

prudent to wear an ensemble that affords a 

large measure of safety as does a pressure suit 

(witness Lockheed test pilot Bill Weaver’s 

SR-71 incident). The challenge is for designers 

to further expand the performance envelope of 

pressure suits by making them even more userfriendly through the use of new and emerging materials, processes, and technologies, 

such as those offered by the emerging field 

of nanotechnologies. Leveraging such future 

technological advancements, while exercising 

due diligence in addressing human factors, will 

quite certainly ensure a continued advancement in the state of the art of pressure suits.

Jack Bassick

Director

David Clark Company Incorporated

Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

vii

Jack Bassick Biography

Jack Bassick Biography

Jack Bassick has worked closely with pressure 

suits for over fifty years, beginning in 1961 

as a physiological training instructor with 

the United States Air Force before joining 

David Clark Company in 1965. Jack’s tenure 

at David Clark has included numerous 

assignments and responsibilities, including 

pressure suit field service at Area 51 with the 

CIA’s A-12 Oxcart program and Edwards 

North Base with the Agency U-2 program. 

Throughout his career, Mr. Bassick has 

participated in the research, development, 

qualification testing, production, crew 

training and field support of numerous 

partial and full pressure suit systems for a 

variety of air and spacecraft applications, 

being awarded a number of pressure suit 

related patents and receiving NASA Astronaut 

Corps’ prestigious Silver Snoopy Award for 

his contributions to Astronaut safety. Jack 

represents the third generation of pressure suit 

specialists at David Clark Company, following 

in the footsteps of founder David M. Clark 

and his chosen successors, John Flagg and 

Joe Ruseckas. Appointed Director of Research 

and Development and elected Executive Vice 

President of David Clark Company in the 

late 1980’s, Mr. Bassick recently retired from 

active employment, remaining involved with 

the company as a director.
Preface
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Preface

ix

Preface

Aeronautics (NACA) effort, raised the state of 

the art for partial-pressure suits, and the company’s early full-pressure suit was first used on 

the Douglas D558-2 program, which was a 

U.S. Navy-NACA effort. Major full-pressure 

suit improvements were made for the X-15 

program, which was a USAF-Navy-NACA 

venture. Ultimately, the Space Shuttle Program, a uniquely NASA enterprise, became 

the most visible user of aviation pressure suits.

There are several items of clothing that are 

relevant to high-altitude flight. All operate 

using a couple of different principles that 

produce similar results. The first garment is 

not directly related to high-altitude flight but 

rather to protecting against high acceleration. 

Nevertheless, the “G-suit” is highly relevant 

to this story since it was developed during 

World War II by many of the same people, 

institutions, and companies that would go on 

to develop pressure suits. During the 1940s, 

and even into the 1950s, it was difficult to 

separate G-suits and pressure suits—both 

were commonly designated “altitude suits” by 

the military, and both were frequently called 

pressure suits, even by the agencies that were 

developing them (a G-suit does, after all, 

of aviation pressure suits from the modern 

beginning. Moreover, the company is also 

the sole survivor among the original pressure 

suit manufacturers and was very enthusiastic 

about telling the story. The other principal 

player in modern American full-pressure suits, 

B.F. Goodrich, has morphed so many times 

that the archives—other than a small collection at the University of Akron—for the 

division that employed pioneering pressuresuit architect Russell S. Colley could not be 

located. Most of what remains are some minor 

reports in various Government archives, and 

there are surprisingly few of those. Unfortunately, therefore, an important part of this 

story is only lightly touched on.

When I began this project, Jack Bassick, 

the executive vice president of David Clark 

Company and a man with great experience 

with pressure suits, commented that it was 

appropriate that the National Aeronautics 

and Space Administration (NASA) sponsor 

this book. Although NASA seldom directly 

funded the development of aviation pressure suits, Jack Bassick pointed out that the 

Bell X-1 program, a joint U.S. Air Force 

(USAF)–National Advisory Committee on 

Anybody who has watched many movies or 

television shows has seen them: the ubiquitous 

silver suits worn by pilots as they explore the 

unknown. They are called pressure suits, and 

one can trace their lineage to famed pilot 

Wiley Post.

Abstractly, the remote ancestor of the modern full-pressure suit is the “dry suit” used by 

turn-of-the-20th-century commercial salvage 

divers. Interestingly, although conceptually 

similar, the two concepts—the diver’s dry 

suit and the aviation full-pressure suit—are 

exactly the opposite functionally; the dry suit 

ensemble worn by divers protected the wearer 

from the hazards of too much pressure (hyperbaric environment), whereas today’s aviation 

counterpart protects the occupant from the 

consequences of too little pressure (hypobaric 

environment). In reality, diving suits have 

played only a small role in the development of 

aviation pressure suits, and then only prior to 

World War II.

Much of this history centers on the David 

Clark Company for several reasons. Perhaps 

most importantly, Clark, and the company 

he founded, has been involved in the concept 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Preface

x

apply pressure to the body). This sometimes 

complicates the story, although I have tried to 

separate the activities as much as possible.

The G-suit, as finally developed, serves two 

main purposes. The first is to prevent the 

pooling of blood in the lower extremities, 

and the second is to provide firm abdominal 

support to enhance the straining maneuver 

pilots use to raise their blood pressure and to 

support the chest cavity to prevent the shifting of major organs. Preventing the pooling 

of blood, particularly in the legs, is accomplished by applying external pressure on the 

thighs and calves to constrict the blood vessels, 

hence increasing total peripheral resistance. 

The external pressure exerted by the G-suit 

cycles in proportion to the +Gz forces being 

experienced by the wearer. Researchers tried 

three different approaches to generate the skin 

counter-pressure. Two approaches used bladders placed against the skin that were covered 

by a layer of restraining cloth; as pressure 

inside the bladders increased, the bladders 

could not expand outward because of the 

restraining fabric, so they expanded inward 

against the skin. Almost everybody has experienced a similar concept: the blood pressure 

cuff, in the doctor’s office. 

The Canadians and Germans used water to 

fill the bladders, but this proved to be heavy 

and uncomfortable for the pilots. The Americans and Australians used gas—compressed 

air for the Americans and carbon dioxide 

(CO2

) for the Australians. It soon became 

clear that the airplane itself could provide 

compressed air more efficiently than could 

a tank of CO2, and all G-suits eventually 

switched to engine-mounted air sources. 

The third way to apply pressure to the legs 

was, mostly, mechanical. Researchers at 

Yale University and General Electric developed a capstan—essentially, a fabric tube that 

ran along the legs—attached to a series of 

interdigitating tapes. As air pressure expanded 

the capstan, the tapes pulled the fabric tightly 

around the leg, constricting it. In theory this 

should be more effective since it applies relatively uniform pressure around the entire circumference of the limb (most of the bladder 

systems only applied pressure to the sides of 

the main muscle groups), but tests showed the 

capstans could not react quickly enough given 

the available pressure sources on airplanes. 

The capstan G-suit was rather quickly forgotten, although the technology later proved 

critical to early partial-pressure suits.

The next item of protective clothing was the 

pressure-breathing vest. The human body 

requires a certain amount of oxygen to survive. As you fly higher, it becomes hard to 

receive this partial pressure of oxygen just by 

breathing normal air at the reduced pressure 

at altitude, so flyers switch to pure oxygen. 

However, as altitude increases further, the 

lungs become unable to provide enough oxygenation of the blood due to the insufficient 

driving pressure. Just prior to World War II, 

researchers determined that to survive at the 

midaltitudes it was possible to force oxygen 

into the lungs under pressure. The problem 

was that the lack of air pressure outside the 

chest made it very difficult to exhale—pilots 

had to deliberately force the air out of their 

lungs. It was unnatural and tiring and effectively a reversal of the natural breathing process (i.e., one had to actively exhale and 

inhalation became passive). A partial answer 

was a pressure vest that operated much like a 

G-suit. A bladder located on the front (and 

sometimes back) of the chest inflated and 

deflated in opposition to the pilot’s breathing (the bladder deflated as the pilot inhaled, 

allowing the chest to expand; as the pilot 

exhaled, the bladder inflated to force air out of 

the lungs). This balanced pressure-breathing 

technique worked satisfactorily up to about 

43,000 feet. 

Next came pressure suits. There are two kinds 

of pressure suits: partial pressure and full pressure. David Clark, the man, once pointed out 

that these were not very good names, but they 

are the ones that stuck. In a partial-pressure 

suit, the counter-pressure is not as complete as 

in a full-pressure suit, but it is placed so that 

shifts in body fluids are kept within reasonable 

limits. Essentially, a partial-pressure suit operates much as a G-suit, except it covers more 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Preface

xi

of the body and operates for prolonged times. 

The suit works by applying pressure over the 

major muscle masses and thorax while keeping 

the joints relatively free of counter-pressure. 

In this way, by striking a balance between 

counter-pressure and limb freedom, sufficient 

mobility is retained to permit the use of the 

suit for limited periods. Partial-pressure suits 

also need to provide substantial counterpressure to the chest to aid in pressure breathing. Two different types of partial-pressure 

suits were developed. The first suits used 

the capstan principle to provide mechanical 

counter-pressure on the arms, legs, and across 

the shoulders and back. Capstans worked here 

because they did not need to react particularly 

quickly, unlike the G-suit. These suits used 

bladders—essentially, a pressure-breathing vest, 

fitted around the chest. The second type of suit 

used bladders everywhere, eliminating the capstans. For the most part, researchers expected 

partial-pressure suits to be emergency “getme-down” suits to allow crews of high-altitude 

aircraft to return to safe altitudes following 

unexpected loss of cabin pressure. However, 

the suit could also support operations at highaltitudes for a relatively limited time such as 

when a crew depressurizes the cabin of a strategic bomber before entering a heavily defended 

area, or when a research pilot takes an experimental aircraft to high altitude for a few minutes of testing. Almost heroically, U-2 pilots 

wore partial-pressure suits for hours while ferreting out secrets over the Soviet Union.1

On the other hand, a full-pressure suit, which 

is an anthropomorphic pressure vessel, creates 

an artificial atmosphere for the pilot. Unlike a 

partial-pressure suit, there is no direct mechanical pressure on the body, and pressure breathing is not required. Instead, a small volume of 

gas surrounds the pilot, and the body responds 

as if the pilot is at some predetermined lower 

altitude, generally between 25,000 and 37,000 

feet. The pilot has to breathe pure (or mostly 

so) oxygen, but it does not need to be forced 

into his lungs under high pressure, as with a 

partial-pressure suit. Because the suit is pressurized, it is often fairly stiff, limiting mobility. 

In fact, providing sufficient mobility has been 

one of the continuing challenges for developers. However, since the pilot is in a “normal” 

atmosphere, he can wear the suit almost indefinitely, at least from a physiological perspective.

One type of pressure suit is not necessarily better than the other, and both partial pressure 

and full pressure suits are still in use around 

the world. Both type of suits have benefits and 

limitations and, by and large, pilots dislike 

both, even while acknowledging their necessity. 

All pressure suits protect against several physiological risks associated with high-altitude 

flying, including:

Hypoxia: The decrease of oxygen in the 

blood caused by reduced atmospheric pressure can affect mental capacity, judgment, 

and vision, and can cause dizziness and 

reduce muscle coordination. Without an 

oxygen supply, pilots can lose consciousness 

in less than a minute after exposure to low 

pressures at high altitudes.

•	 Decompression sickness (also known as 

“aviator bends”): This includes severe joint 

pain caused by nitrogen coming out of 

solution in blood and tissues as a result of 

a rapid decrease in atmospheric pressure. 

Severe cases can result in death.

•	

•	

Armstrong Line: The altitude (roughly 

63,000 feet) at which water goes from a 

liquid to a gas (i.e., boils) at body temperature. Exposure above this altitude can cause 

unconsciousness and result in rapid death 

due to hypoxia, decompression sickness, 

and severe gas expansion.

There are, of course, many other pieces of protective clothing that are intimately related to 

pressure suits, including helmets, gloves, boots, 

and oxygen masks, plus ancillary equipment 

such as regulators, controllers, and valves. The 

focus of this book is on the suits themselves 

and why and how they were developed and 

fielded. The other components are covered in 

passing as seems appropriate, but their detailed 

development history is left to others.

It should also be understood that the focus 

of this book is aviation pressure suits, not 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Preface

xii

spacesuits. Although the two pieces of clothing 

are generally thought to be the same, in reality 

they differ in several ways. A spacesuit has to 

provide additional protection from radiation 

(although some pressure suits also provide limited radiation protection) and impact strikes 

(from micrometeorites and orbital debris) 

and also be more self-contained since there 

is often not a vehicle attached to the suit to 

provide oxygen and power. A full-pressure suit 

normally does not provide its own oxygen or 

power except for very limited times after an 

ejection or bailout, and it usually has some 

sort of anti-suffocation feature in which the 

helmet vents to the atmosphere if the oxygen 

supply is exhausted. In addition, most pressure 

suits provide some sort of exposure protection 

in case the pilot finds himself in water after 

an ejection. Pressure suits, partial and full, can 

allow a pilot to survive in a vacuum for a limited period, but that is not their primary focus. 

The history of spacesuits has been well covered 

in literature; this book attempts to fill the void 

regarding aviation pressure suits.

ACKNOWLEDGMENTS 

No book can be produced in a vacuum 

(pun intended), especially one that attempts 

to cover 75 years of technology development. 

The project would not have gotten started 

without Tony Springer at NASA Headquarters. Many people helped during my research, 

and I am indebted to each of them. 

In particular, a small group of people went 

above and beyond the call, including: Robert 

R. “Bob” Banks (David Clark Company), 

John W. “Jack” Bassick (David Clark Company), Ed Dubois (David Clark Company), 

Dennis Gilliam, Joseph A. Ruseckas (David 

Clark Company), Dr. Jan Stepanek (Mayo 

Clinic), and Brett Stolle (National Museum 

of the United States Air Force). 

Others who graciously contributed include: 

Aric Ahrens (Paul V. Galvin Library), 

Tom Anderson (SpaceAge Control), William 

Ayrey (ILC Dover), Dr. James P. Bagian, 

TD Barnes (Roadrunners Internationale), 

Roger J. Barnicki (NASA/Dryden Flight 

Research Center, retired), Dan Barry (David 

Clark Company), Thomas W. Bowen (9th 

Physiological Support Squadron, Beale Air 

Force Base), Steven Bromley (Gentex Corp.), 

Dr. Fred Buick (Defence Research and Development Canada), Tony Chong (Northrop 

Grumman), Dr. Jonathan B. Clark, William J. 

Close (NASA/Johnson Space Center), 

Kenneth S. Collins (Dutch 21), Daniel 

Coulom (Hamilton Standard), Regina 

(Conrad David Clark Company), Rob 

Coppinger (Flight International), A. Scott 

Crossfield, William H. Dana (NASA/

Dryden), John J. Devine, Jr. (Government 

Documents Department, Boston Public 

Library), Duane W. Deal (Brig. Gen, USAF, 

Ret.), Archie Difante (Air Force Historical 

Research Agency), John Dodson (University 

of Sydney), Gail E. Farr (National Archives 

Research Agency Mid Atlantic Region), Gail 

Fithian (Government Documents Department, Boston Public Library), Alan Freeman 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Preface

xiii

(David Clark Company), Steve Gaut (FederalMogul), Christian Gelzer (NASA/Dryden), 

Sandy Gettings, Terry Greenfield (NASA/

Kennedy Space Center), Richard H. Graham 

(Col., USAF, Ret.), Wes Henry (National 

Museum of the United States Air Force), John 

C. Harper (Chevron), Jan K. Herman (Bureau 

of Medicine and Surgery Historian), Craig 

A. Holbert (University of Akron), Marty 

Isham, Eliza L. Johnson (NASA/Johnson 

Space Center), Linda F. Jones (Chevron), 

Donald Lacey (ILC Dover-Johnson Space 

Center), Tony R. Landis (NASA/Dryden), 

Ivy Leaf (Webmaster at Corsetiere), Denny 

Lombard (Lockheed Martin, Ret.), Michael 

J. Lombardi (Boeing Historian), Betty J. Love 

(NASA/Dryden, Ret.), Joseph D. Malone 

(David Clark Company), Daniel R. McCarter 

(David Clark Company), Jewel M. Melvin 

(Air Force Material Command/576th Aircraft Sustainment Squadron), Marcel Meyer 

(Fédération Aéronautique Internationale), 

Roger Mott (Emil Buehler Library), Mike 

Moore (Lockheed Martin), Francis J. “Frank” 

Murray (Dutch 20), Jennifer Ross-Nazzal 

(NASA/Johnson Space Center, History 

Office), William Norton, Kenneth Przybyla 

(Carleton Controls), Don Pyeatt, Gary Ray 

(NASA/Kennedy Space Center), Dr. Sally 

K. Ride, Dr. Erik L Ritman (Mayo Clinic), 

Dr. Angus H. Rupert (U.S. Army Aeromedical Research Laboratory), Bruce W. Sauser 

(NASA/Johnson Space Center), Carlton F. 

“TC” Thomas (USA/Johnson Space Center), 

Kenneth S. Thomas (Hamilton Standard), 

Tommy Thomason, Malcom V. “Mike” Todd 

(Red Bull Stratos), Lucien Van Oosten (Gentex Corp.), Col. Donald J. White (USAF/

HQ), Maura White (NASA/Johnson Space 

Center), Lt. Col. Charles P. Wilson (USAF, 

Ret.), Ronald C. Woods (NASA/Kennedy 

Space Center), and Dr. James O. Young 

(Air Force Flight Test Center, History Office).

DEDICATION

During this project, two men intimately 

familiar with pressure suits passed away. 

Joseph A. Ruseckas, from the David Clark 

Company, helped design many of the pressure 

suits described in this book, while USAF test 

pilot Maj. Gen. Robert M. White made good 

use of the suits as he became the first man to 

fly a winged aircraft above Mach 4, Mach 5, 

and Mach 6 and higher than 200,000 and 

300,000 feet. I had the good fortune to count 

both men as friends. They made untold 

contributions to aviation, and both will be 

missed. Godspeed.
1
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

15

Chapter 1: Introduction

1: Introduction

One of the unidentified authors of an Air 

Force history of the Wright Air Development 

Center wrote an epilogue that conveyed the 

awe associated with aviation pressure suits 

during the mid-1950s. 

The high point in the development of 

the altitude suit was reached on 17 June 

1954 when Maj. Arthur Murray rode 

the rocket-propelled X-1A to an altitude 

in excess of 90,000 feet. When Murray 

reached the peak of his record setting 

flight, he was atop more than 97 percent 

of the atmosphere on the planet. Outside 

the cabin of the X-1A, the rarified air was 

only about two percent as dense as that 

at sea level. For all practical purposes, he 

was in the airless environs of outer space. 

While he did not use the high altitude suit 

that he wore, he proved that a man could 

survive outside the earth’s atmosphere for 

short periods if he took along his own 

environment. The lesson for the future 

was patent: The high altitude suit which 

had evolved in the first decade after World 

War II probably would—in one form 

or another—accompany man when he 

finally escaped the confines of his rapidly 

shrinking planet and ventured into the 

vast emptiness of space. In the interim, the 

altitude suit appeared to be the inevitable 

armor of man as he strove to continue his 

climb from the caves to the stars.1

Space Shuttle astronauts who donned their 

David Clark Company S1035 full-pressure 

suits were living proof.

HORROR VACUI

Vacuum, adjective; a space entirely 

devoid of matter; an enclosed space 

from which matter, esp. air, has been 

partially removed so that the matter 

or gas remaining in the space exerts 

less pressure than the atmosphere.2

Although difficult to imagine today, man 

debated the question of whether a vacuum 

could exist for centuries. Ancient Greek philosophers did not admit to the existence of a 

vacuum, asking themselves “how can ‘nothing’ 

be something?” Islamic philosopher Al-Farabi 

(970–850 B.C.E.) appears to have conducted 

the first recorded experiments concerning the 

existence of the vacuum when he investigated 

handheld water plungers, with inconclusive 

results.3

 Plato (427–347 B.C.E.), mathematician, writer of philosophical dialogues, and 

founder of the Academy in Athens, thought the 

idea of a vacuum inconceivable. He believed 

that all physical things were instantiations of an 

abstract Platonic ideal and could not imagine 

an “ideal” form of a vacuum. Aristotle (384–

322 B.C.E.), philosopher, student of Plato and 

teacher of Alexander the Great, believed that 

a vacuum was a logical contradiction: nothing 

could not be something. The common view, 

attributed to Aristotle and held true for a millennium, that nature abhorred a vacuum was 

called horror vacui (literally, a fear of empty 

spaces).4 It all made perfect sense at the time.

In medieval Europe, the Catholic Church, a 

major influence on science and philosophy, 

held the idea of a vacuum to be heretical since 

the absence of anything implied the absence 

of God, and harkened to the void that existed 

prior to the story of Genesis. The Inquisition 

made certain this idea was held true.

However, this began to subtly change in 1277, 

when Bishop Étienne Tempier of Paris decreed 

there were no restrictions on the powers of 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

16

God, which led to the conclusion that God 

could create a vacuum if He so wished.5 So, 

although the concept of a vacuum was no 

longer heretical, neither was it much mentioned. Another 400 years would pass before 

the concept of a vacuum was anything but a 

philosophical discussion, usually conducted 

in private. 

From the science of the 21st century, it is difficult to understand how a sensible concept 

of a vacuum could emerge without a corresponding concept of pressure. Yet, it took 

several hundred years for the two ideas to be 

linked. Interestingly, despite the science of 

the day not understanding the physics behind 

the device, suction pumps were becoming 

increasingly common devices used to move 

water. The popular understanding was that 

these devices created a partial vacuum on one 

end, and water rushed from the other end to 

fill the void in accordance with horror vacui.

Some questioned this explanation. An anonymous 13th century pupil of German philosopher and mathematician Jordanus de Némore 

(1225–1260) understood that pressure in a 

liquid increased with depth, but the publication of Némore’s book in which the discussion 

appeared was delayed for three centuries.6 Independently, Dutch philosopher Isaac Beeckman 

(1588–1637) correctly theorized that air pressure was what caused a water pump to work, 

not horror vacui. Beeckman did not publish his 

ideas but kept an extensive journal, from which 

his brother published some of his observations 

in 1644. However, given the relative obscurity 

of Beeckman, this went largely unnoticed. In 

1615, the Tuscan mathematician, astronomer, 

and philosopher Galileo Galilei (1564–1642) 

wrote, “that all the air ... weighs nothing.”7

Against this background, the Italian Giovanni 

Batista Baliani (1582–1666), among others, 

noted that pumps would not draw water higher 

than 34 feet and siphons would not work over 

hills of the same height. Baliani described this 

effect in a letter to Galileo, who responded with 

the usual explanation: the pump or siphon created a partial vacuum, and horror vacui caused 

water to rush in to fill the void. Nature would 

not allow the partial vacuum to exist long 

enough to move water higher than 34 feet. 

Baliani, however, did not accept this answer 

and believed that a vacuum was possible. 

He also believed that air had weight. To 

test Baliani’s theories, some time prior to 

1643, Gasparo Berti and Raffaello Magiotti 

built a 36-foot tube, filled it with water, and 

plugged both ends. They placed one end of 

the upright tube in a basin of water, removed 

the bottom plug, and watched water pour 

out into the basin. However, only part of the 

water in the tube flowed out, and the level of 

the water inside the tube stayed at 34 feet, the 

same height others had observed as the limit 

of a siphon.8

Perhaps more important was that this experiment left a space above the water in the tube 

that had no opening for air to refill. Berti 

believed the space above the water was a 

vacuum, although the followers of Aristotle 

vigorously contested the claim. One of the 

most vocal was René Descartes (1596–1650), 

a French philosopher and scientist who argued 

that the space was filled with a substance called 

aether, which was able to flow through tiny 

pores in the tube to replace the receding water.9

Magiotti apparently mentioned this experiment to Evangelista Torricelli (1608–1647), 

who had been Galileo’s assistant for the last 

3 months of the philosopher’s life. Torricelli 

had radically different theories about why 

pumps and siphons worked and decided in 

1643 to duplicate much of Berti’s experiment to prove those theories. In a book written 300 years later, Isaac Asimov provided a 

description of Torricelli’s experiment:

It occurred to Torricelli that the water was 

lifted, not because it was pulled up by the 

vacuum, but because it was pushed up 

by the normal pressure of air.... In 1643, 

to check this theory, Torricelli made use 

of mercury. Since mercury’s density is 

13.5 times that of water, air should be 

able to lift it only 1/13.5 times as high 

as water, or 30 inches. Torricelli filled a 

6-foot length of glass tubing with mercury, stoppered the open end, upended 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

17

it in a dish of mercury, unstoppered it, 

and found the mercury pouring out of 

the tube, but not altogether: 30 inches 

of mercury remained, as expected.10

In conducting this experiment, Torricelli 

had built the first mercury barometer and 

developed a convincing argument that the 

space at the top of the tube was a vacuum. 

The height of the column was limited to the 

maximum weight that atmospheric pressure 

could support. In honor of his contributions, 

his name was given to one of the early 

measures of pressure. Oddly, however, unlike 

Kelvin and Pascal, who were honored using 

their full names, only half of Torricelli’s was 

used, and then without a leading capital 

letter: torr. Despite the significance of the 

experiment, it took 20 years for the first 

full account to be known. In “De motu 

gravium,” which was published as part of 

the 1644 Opera Geometrica, Torricelli also 

proved that the flow of liquid through an 

opening is proportional to the square root 

of the height of the liquid, now known as 

Torricelli’s Theorem.11

As important as Torricelli’s contribution 

was, the Aristotelian philosophers held fast, 

and it would take another legendary scientist 

to finally put the debate to rest. By 1646, 

Blaise Pascal (1623–1662), a French mathematician, physicist, and philosopher, had learned 

of Torricelli’s experiments with barometers. 

Having replicated the experiment, Pascal questioned what force kept some mercury in the 

tube and what filled the space above it. Following more experimentation, in 1647 Pascal 

published Experiences nouvelles touchant le 

vide,12 which detailed rules describing to what 

degree various liquids could be supported by 

air pressure. It also provided reasons why it 

was indeed a vacuum above the column of liquid in a barometer tube. Science was, slowly, 

supplanting philosophy.

However, Pascal went further. If, as he and 

Torricelli suspected, air had weight caused 

by the miles-thick atmosphere, it should 

decrease at higher altitudes. Pascal wrote to his 

brother-in-law, Florin Perier, who lived near 

the Puy-de-Dôme volcano in south-central 

France, requesting he perform an experiment. 

Perier was to take a barometer up the Puy-deDôme and make measurements along the way 

of how high the column of mercury stood. 

In 1648, Perier meticulously carried out the 

experiment and found that Pascal’s predictions 

were correct: the mercury barometer stood 

lower at higher altitude.13 The Puy-de-Dôme 

experiment ultimately caused the Aristotelian 

philosophers to admit defeat and concede 

that air had weight. Within the International 

System of Units (abbreviated SI from the 

French “Le Système International d’Unités”), 

the Pascal (Pa) replaced the torr as the standard 

measurement of pressure—this time using the 

entire capitalized surname.

In 1650, German scientist and politician 

Otto von Guericke (1602–1686) invented 

the first vacuum pump and demonstrated 

the force of air pressure with dramatic 

experiments. The most famous used a pair of 

20-inch-diameter copper hemispheres14 with 

mating rims sealed with grease. Guericke used 

his pump to remove the air in the enclosure 

and then harnessed a team of eight horses to 

each half and showed that they were not able 

to separate the hemispheres. When Guericke 

let air into the enclosure, the halves easily 

separated. He repeated this demonstration in 

1663 at the court of Friedrich Wilhelm I of 

Brandenburg in Berlin, using 24 horses.15

With his experiments, Guericke dramatically 

disproved the hypothesis of horror vacui

and demonstrated that the pressure of 

the surrounding fluids pushed substances 

instead of a vacuum pulling them. Later, 

Robert Boyle (1627–1691) and Robert Hooke 

(1635–1703) improved Guericke’s design. 

In 1659, using his and Hooke’s Machina 

Boyleana, or Pneumatical Engine, Boyle 

began a series of experiments on the properties 

of vacuum. Boyle published an account of 

these in 1660 as “New Experiments PhysicoMechanical, Touching the Spring of the Air, 

and its Effects.”16 Among the critics of these 

experiments was a Jesuit, Franciscus Linus 

(1595–1675), and it was while answering his 

objections that Boyle made his first mention 

that the volume of a gas varies inversely to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

18

the pressure of the gas. Today this is known as 

Boyle’s Law. 

Oddly, the study of vacuum then, largely, 

lapsed until 1850, when August Toepler 

(1836–1912) invented an improved mercury 

piston pump called, logically enough, the 

Toepler pump. Then, in 1855, Heinrich 

Geissler (1814–1879) invented the mercury 

displacement pump and achieved a record 

vacuum of about 10 Pa (0.1 torr). A number 

of electrical properties become observable 

at this vacuum level, allowing Geissler 

to invent the basic technologies behind 

fluorescent tube lights, vacuum tubes, and, 

ultimately, cathode ray tubes. Shortly after 

this, Hermann Sprengel (1834–1906) 

invented a continuously operable vacuum 

pump, naturally called the Sprengel pump. 

Finally, the concepts of pressure and vacuum 

were well established.17

STRUCTURE OF THE ATMOSPHERE

All of this experimentation, in some form, 

concerned the atmosphere. The atmosphere 

is the gaseous envelope that surrounds 

Earth from sea level to an altitude of about 

120,000 miles, held in place by gravity. Without this envelope of gas, life as we know it 

could not exist. The atmosphere provides 

breathing air and protection from ultraviolet 

radiation, and it acts as a layer of insulation to 

maintain a relatively constant temperature. 

The atmosphere consists of several concentric 

layers, each displaying its own unique characteristics, known as spheres. Thermal variances within the atmosphere help define these 

spheres. Between each of the spheres is an 

imaginary boundary, known as a pause.18

The troposphere extends from sea level to 

about 26,500 feet over the poles and nearly 

52,500 feet above the equator. Temperatures 

decrease 3.6 degrees Fahrenheit (oF) for each 

1,000 feet in altitude in the troposphere and 

continue to decrease until the rising air mass 

achieves an altitude where temperature is in 

equilibrium with the surrounding atmosphere. 

The troposphere contains water vapor and 

the vast majority of weather happens in this 

layer. The tropopause is the atmospheric 

boundary between the troposphere and the 

stratosphere. Going upward from the surface, 

it is the point where air ceases to cool with 

height and becomes almost completely dry.

The stratosphere extends from the tropopause 

to roughly 160,000 feet (about 30 miles). Aviation pressure suits, the subject of this book, are 

meant to allow humans to survive in this layer, 

although many will function at higher altitudes. 

The stratosphere is subdivided into two regions 

based on their thermal characteristics. Although 

Table 1—Percentages of Atmospheric Gases

Gas Symbol Volume (percentage)

Nitrogen N2 78.0840

Oxygen O2 20.9480

Argon Ar 0.9340

Water Vapor H2

O 0.4000

Carbon Dioxide CO2 0.0314

Neon Ne 0.0018

Helium He 0.0005

Methane CH4 0.0001

Krypton Kr 0.0001

Hydrogen H <0.0001

Source: National Oceanic and Atmospheric Administration at 

http://esrl.noaa.gov/gsd/outreach/education/climgraph/index.html
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

19

these regions differ thermally, the water vapor 

content of both is virtually nonexistent.

The first region is the isothermal layer where 

temperature is a constant −67 oF. The presence 

of fast-moving jet streams, both here and in 

the upper regions of the troposphere, cause 

the turbulence traditionally associated with 

the stratosphere.

Rising temperatures characterize the second 

region, which contains the ozone layer. This 

serves as a double-sided barrier that absorbs 

harmful solar ultraviolet radiation while 

allowing solar heat to pass through unaffected. 

Table 2—Atmospheric Data

Altitude 

(feet)

Atmospheric Pressure 

(psi)

Atmospheric Pressure 

(mm Hg)

Oxygen PartialPressure (mm Hg)Temperature

(oF)

Time of Useful 

Consciousness

100,000 0.15 8 2 −51 0

90,000 0.25 13 3 −56 0

75,000 0.50 27 6 −65 0

63,000 0.73 47 10 −67 0

50,000 1.69 88 18 −67 0–5 seconds

43,000 2.40 123 26 −67 5–10 seconds

40,000 2.72 141 30 −67 10–20 seconds

35,000 3.50 179 38 −66 30–60 seconds

30,000 4.36 226 47 −48 1–3 minutes

25,000 5.45 282 59 −30 3–5 minutes

20,000 6.75 349 73 −12 10–20 minutes

18,000 7.34 380 80 −5 20–30 minutes

15,000 8.30 429 90 5 30+ minutes

10,000 10.11 553 116 23 Nearly Indefinitely

7,000 11.30 587 123 34 Indefinitely

Sea Level 14.69 760 160 59 Indefinitely

Data for an ISO standard day (59 °F / 15 °C) at 40 degrees latitude. 

Source: U.S. Naval Flight Surgeon’s Manual, Naval Aerospace Medical Institute, Third Edition, 1991.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

20

In addition, this region reflects heat back 

toward the surface of Earth, keeping the lower 

regions of the atmosphere warm, even at night 

during the absence of significant solar activity.

The mesosphere extends from the stratopause 

to an altitude of 264,000 feet (50 miles). 

Temperatures decline from a high of 26 oF 

at the stratopause to nearly −171 oF at the 

mesopause. Consisting of meteor dust and 

water vapor and shining only at night, noctilucent clouds are a visible characteristic of 

this atmospheric layer.

The thermosphere, characterized by temperatures that vary in direct relation to solar activity, extends from the mesopause to an altitude 

of about 310 miles. Temperature ranges from 

−171 oF at the mesopause to 2,700 oF during 

periods of extreme solar activity. Another characteristic of the thermosphere is the presence 

of charged ions that are the result of highspeed subatomic particles emanating from the 

sun. These particles collide with atmospheric 

gas atoms and split them apart, resulting in a 

large number of charged particles (ions).

The exosphere extends from the thermopause 

to 120,000 miles, and from most perspectives, 

it is indistinguishable from outer space. 

The atmosphere contains many gases 

(although only a few are essential to human 

survival), including mostly nitrogen, oxygen, 

and carbon dioxide. Table 1 shows the 

concentrations of gases commonly found in 

the atmosphere.19

Although a vital ingredient in the chain of 

life, nitrogen is not readily used by the human 

body. However, respiration saturates body 

fluids and tissues with nitrogen, which can 

result in evolved-gas disorders because of the 

decreased solubility of nitrogen at higher 

altitudes due to lower ambient pressure.

Oxygen is the second most plentiful gas in 

the atmosphere. Respiration unites oxygen 

and sugars to meet the energy requirements of 

the body, and the lack of oxygen in the body 

at altitude will cause drastic physiological 

effects that can result in death. To function 

normally, the healthy human body requires 

approximately 3 pounds per square inch (psi) 

of oxygen pressure in the lungs—conveniently, 

about what is available at sea level (21 percent 

of 14.7 psi is 3.1 psi).

Carbon dioxide is the product of cellular respiration in most life forms. Although not present 

in large amounts, CO2

 in the atmosphere plays 

a vital role in maintaining the oxygen supply 

of Earth. Through photosynthesis, plants use 

CO2 to create energy and release oxygen as a 

byproduct. Because of animal metabolism and 

photosynthesis, CO2 and oxygen (O2) supplies 

in the atmosphere remain constant.

As designed, human beings are not well 

equipped to operate at the altitudes normally 

found in the higher mountainous regions 

of Earth, let alone in the upper atmosphere. 

An average person in decent health normally 

has no problem with daily activities at 

altitudes below 10,000 feet, although 

disorders impacting oxygen uptake, delivery, 

or utilization (such as smoking or lung 

disease) can result in shortness of breath at 

any altitude. Above 10,000 feet, even wellconditioned individuals feel the effect of 

exertion much quicker than at sea level. As 

altitude increases, there are physiological 

limits to the maximum time a human can 

continue to function. 

ATMOSPHERIC PRESSURE

Standard atmospheric pressure, or barometric 

pressure, is the force (that is, weight) exerted 

by the atmosphere at any given altitude. 

Atmospheric pressure decreases with increasing altitude, making barometric pressure 

of great concern to aircrews because oxygen 

diffusion in the body depends on total 

barometric pressure.20

There are many units of pressure, including 

millimeters of mercury (mm Hg, for all 

intents, the same as a torr, and used in this 

book), inches mercury (in. Hg), inches of 

water (in. Aq), torr, Pascals (and its standard 

metric derivatives), psi, and the Standard 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

21

Atmosphere (atm). The approximate 

conversations are as follow: 

1 atmosphere = 760 mm Hg (torr) = 14.69 

psi = 101.325 kilopascals (kPa).

A close relationship exists between atmospheric pressure and the amount of the various gases in the atmosphere, an effect known 

as Dalton’s Law of partial pressures. Dalton 

demonstrated that the pressure exerted by a 

mixture of ideal (nonreacting) gases is equal to 

the sum of the pressures that each gas would 

exert if it alone occupied the space filled by 

the mixture. Put another way, the pressure of 

each gas within a gaseous mixture is independent of the pressures of the other gases in the 

mixture. The independent pressure of each 

gas is termed the partial pressure of that gas. 

Mathematically, Dalton’s Law is expressed as:

Pt = PN + PO2

 + PCO2 + ... (assuming 

constant volume and temperature)

In this equation, Pt represents the total 

pressure of the mixture and PN, PO2, 

PCO2 represent the partial pressures of each 

individual gas (nitrogen, oxygen, and carbon 

dioxide, in this example).

Dalton’s Law illustrates that increasing altitude 

results in a proportional decrease of partial 

pressures of gases found in the atmosphere. 

Although the percentage concentration of 

gases remains constant with increasing altitude, 

each gas’s partial pressure decreases in direct 

proportion to the total barometric pressure.

Changes in the partial pressure of oxygen dramatically affect respiratory functions within 

the human body, and rapid decrease in the 

partial pressure of oxygen may quickly result 

in physiological impairment. Although a person may not notice this impairment at lower 

altitudes, the effects are cumulative and grow 

progressively worse as altitude increases. Fortunately, within certain limits, the human body 

can acclimatize and hence improve its performance in a hypoxic environment over days 

and weeks. Decreases in the partial pressure of 

nitrogen (N2

), especially at high altitude, can 

lead to a decrease in the solubility of N2 in the 

body and result in decompression sickness.

Decompression sickness (DCS), also called 

the bends and caisson disease arises from the 

precipitation of dissolved gasses into bubbles 

inside the body on depressurization. DCS 

most commonly refers to a specific type of 

scuba diving hazard but may be experienced in 

other depressurization events such as working 

in caissons, flying in unpressurised aircraft, 

and space-based extra-vehicular activity. Its 

effects may vary from joint pain and rashes to 

paralysis and death.21

At altitudes above 28,000 feet, the body 

requires 100 percent oxygen to remain 

conscious for any useful time. Breathing 

100 percent oxygen at 34,000 feet is 

physiologically equivalent to breathing air at 

sea level. Breathing 100 percent oxygen at 

40,000 feet is equivalent to breathing air at 

10,000 feet. At altitudes between 40,000 and 

50,000 feet, pressure breathing must be used 

wherein the breathing cavity, for example 

the helmet, is maintained at a small positive 

pressure. This increases the ability of the body 

to absorb the oxygen into the blood stream. 

At altitudes above 50,000 feet, humans must 

resort to using pressure breathing and a partialpressure suit or, alternately, a full-pressure 

suit. Being at very high altitudes without a 

pressure suit is extremely dangerous and results 

in a condition in which the free nitrogen in 

the blood bubbles from solution, resulting in 

severe organ injury or death in minutes.22

There are two absolutes when dealing with 

humans and ever-decreasing atmospheric 

pressures: the first occurs at about 43,000 feet 

altitude and the second at 63,000 feet.23

The first, 43,000 feet, is the altitude at 

which it is impossible, without resorting to 

pressure breathing, for the lungs to absorb 

enough oxygen to sustain oxygenation and 

consciousness, even if breathing 100 percent 

oxygen. Pressure breathing is pure oxygen 

delivered under pressure—usually less than 

1 psi (52 mm Hg) but enough to physically 

force the gas into the lungs. Unfortunately, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

22

it is necessary to forcefully exhale the carbon 

dioxide, and then relax sufficiently to allow 

more pressurized oxygen to enter the lungs. 

As Donn Byrnes describes in Blackbird Rising, 

“This pressure breathing is conducted under 

very low mask pressure, usually equivalent to 

the weight of a column of water about five 

inches high. Imagine blowing a five-inch plug 

of water out of your snorkel in the swimming 

pool each time you exhaled, and doing that 

for a couple of hours or more.” It is hard 

work and represents a complete reversal of 

a human being’s normal physiology with 

respect to breathing. Essentially, nobody can 

function well under pressure breathing for any 

prolonged length of time, even with specially 

designed suits that assist with exhalation.24

The second absolute is more frightening. At 

approximately 63,000 feet, called the Armstrong Line, pressure decreases to only 5 percent of sea level. The vapor pressure of water 

(47 mm Hg) at this altitude is the same as the 

atmospheric pressure (47 mm Hg) and water 

boils at the normal temperature of the human 

body (98.6 oF). It is important to note that 

this applies to unconfined water, such as saliva 

and tears. Normal human diastolic blood pressure is sufficiently high that, contrary to oftrepeated myth, a person’s blood will not boil 

in a vacuum, although there are many other 

environmental threats such as hypoxia, cold, 

and trapped gas expansion that will quickly kill 

an unprotected human above this altitude.25

PHYSIOLOGICAL ISSUES OF HIGHALTITUDE FLIGHT

The homeostatic responses in humans to 

sudden exposure to low barometric pressures 

are limited in their adaptive capabilities since 

this hostile environment is foreign to human 

physiology. Hence, there is no opportunity 

for a sufficient adaptive response. Exposure 

results in a rapid onset of unconsciousness 

unless otherwise protected by artificial means. 

If there should be a sudden or even slow loss 

of cabin pressurization at altitudes above 

40,000 feet, even while breathing 100 percent 

oxygen at ambient pressures, the time of 

useful consciousness (TUC), the duration in 

which the pilot can perform basic emergency 

tasks, begins to shrink. At 40,000 feet, 

breathing pure oxygen at ambient pressure, 

the TUC is theoretically indefinite (ignoring 

decompression sickness). This ability decreases 

rapidly, and an increment of only 3,000 feet 

(to 43,000 feet) makes it necessary to employ 

pressure breathing to have any TUC. By 

50,000 feet, even breathing pure oxygen at 

ambient pressure provides less than 5 seconds 

TUC. The physiology and biochemistry of 

hypoxia in humans is beyond the scope of 

this book, and only the pertinent details are 

summarized here.26

In high-altitude flight, a structural failure 

in a pressurized cabin or loss of cabin pressure control would be catastrophic without 

supplemental protection for the crew. The 

physiological effects of a rapid decompression include acute hypoxia, effects on the 

gas-containing cavities of the body, decompression sickness, thermal exposure, and ebullism (formation of bubbles in body fluids). 

Less rapid but equally debilitating effects of 

unpressurized flight at high altitude include 

hyperventilation, fatigue, reduction in effective circulating blood volume, and fainting 

associated with pressure breathing. Also, 

acceleration forces during high-speed egress 

(ejection) can have a profound consequence 

on the skeletal structure and the cardiovascular system. All of these reactions can have 

potentially grave effects upon aircrew performance and mission effectiveness and all are 

avoidable by the employment of appropriate 

life support equipment and adequate training. 

Most pressure suits maintain the crewmember 

at an equivalent altitude of approximately 

34,000 feet breathing 100 percent oxygen, 

which is roughly equivalent to breathing sea 

level air, thereby preventing most of these 

problem areas.27

Hypoxia: Altitude hypoxia results when the 

oxygen partial pressure in the lung falls below 

that comparable to sea level. However, it is 

not generally significant until the alveolar 

oxygen tension falls below a 10,000-foot 

equivalent. At 10,000 feet, the reduced ability 

to learn new tasks can be measured and consequently 10,000 feet is used as the altitude 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 1: Introduction

23

that supplemental oxygen is considered necessary.28 As the partial-pressure of oxygen in the 

inspired air continues to drop, the signs and 

symptoms of hypoxia become more evident 

and include loss of peripheral vision, skin 

sensations (numbness, tingling, or hot and 

cold sensations), cyanosis, euphoria and 

eventually unconsciousness at higher altitudes. 

Up to an altitude of 34,000 feet, increasing 

the percentage of oxygen allows an approximation of sea level oxygen equivalent. Above 

40,000 feet, breathing 100 percent oxygen 

without additional pressure is not sufficient 

for efficient aircrew performance. Pressure 

breathing is required and is accomplished 

by use of an oxygen system that delivers 

100 percent oxygen at greater than ambient 

pressures. However, the pressures needed 

to sustain consciousness above 50,000 feet 

rapidly become intolerable.29

Mechanical Effects: During a cabin depressurization, gases trapped within the intestinal 

tract, nasal sinuses, middle ear, and lungs 

will expand. The magnitude of the effect 

on the gas-containing cavities of the body is 

directly proportional to the range and rate 

of change of pressure. Serious consequences 

result when there is an occlusion or partial 

occlusion between a gas-containing cavity 

and the environment.30

Decompression Sickness: Body tissues contain dissolved gas, principally nitrogen, in 

equilibrium with ambient pressure. When 

ambient pressure is reduced, nitrogen bubbles 

form in the body tissues. If the drop in pressure is not too great or too fast, bubbles 

evolved in the tissues are safely carried to 

the lungs by the vascular system, where the 

evolved nitrogen is eliminated. Prolonged 

exposure to altitudes in excess of 25,000 feet 

may lead to one or more of the symptoms of 

DCS, such as the bends, chokes, and circulatory and neurological disturbances. Recent 

studies have established the need for increasing the pressure differential from 5 to 7 psi in 

future aircraft. Air Force researchers believe 

this increased pressure differential provides 

less risk of DCS during prolonged exposure to 

cabin altitudes greater than 20,000 feet.31

Ebullism: When the total barometric pressure 

is less than the vapor pressure of tissue fluid at 

body temperature (47 mm Hg), vaporization 

of the body fluids occurs. This occurs in the 

nonpressurized portions of the body at altitudes above 63,000 feet. However, exposure 

of peripheral regions of the body (e.g., the 

hands) to pressures less than the vapor pressure of the tissue fluids leads to vaporization 

of these fluids with little or no impairment of 

performance. When combined with low environmental temperatures, the evaporative cooling associated with vaporization may accelerate 

freezing and drying of exposed tissues. While 

wearing only a mask for short exposures above 

63,000 feet, vision is affected as a result of 

tearing and blinking during pressure breathing, 

which effectively blinds the crewmember.32

Thermal Extremes: The effects of the low 

temperatures following loss of cabin pressure 

at high altitude can cause impaired function 

and eventual tissue damage to exposed regions 

of the body; or, if exposure occurs over a 

longer duration, it could cause a drop in core 

temperature causing a progressing impairment 

of performance followed by unconsciousness 

and, eventually, death. An aircrew member 

wearing normal flying clothing with a mask 

and gloves will not suffer any serious damage 

during a short exposure (5 minutes) to the 

lowest temperature conditions encountered 

at high altitude. Exposure beyond this time 

will lead to more severe peripheral cold injury 

unless appropriate clothing and heating garments are worn. The garment must also protect against heat when the temperatures on 

the outer surfaces of Mach 3 aircraft approach 

560 oF, and it also must protect against the 

thermal pulse of ejection at Mach 3.33
2
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

25

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

2: Mark Ridge, Wiley Post, and John Kearby

Pressure suits, usually called spacesuits by the 

public (although these are but one example 

of this type of garment), are essentially taken 

for granted today. Seventy-five years ago, they 

were the stuff of science fiction. These suits 

serve several necessary purposes, with supplying the correct partial pressure of oxygen 

the most obvious, although masks or full-face 

helmets can also accomplish this somewhat 

less efficiently, at least at the middle altitudes. 

Their most important purpose, however, is 

to protect the pilot against the increasingly 

low atmospheric pressures encountered at 

high altitude—pressures that reach essentially 

zero above about 250,000 feet—and the terrible cold encountered at extremely high altitude.1

 Years before the involvement of 

large Government, academic, and corporate 

entities, however, comes the story of a couple 

of visionaries and the early pioneering work 

on full-pressure suits.

A distant precursor of the full-pressure suit 

was, arguably, the dry suit used by turn-ofthe-century commercial salvage divers, complete with their brass helmets and weighted 

boots. During 1920, renowned Scottish physiologist Dr. John Scott Haldane (1860–1936) 

seemingly was the first to suggest that a suit 

similar to the diver’s ensemble could protect 

an aviator at high altitudes. There appeared, 

however, to be little immediate need for such 

a garment. The normally aspirated pistonpowered airplanes of the era were incapable 

of altitudes much in excess of 20,000 feet, 

and the major concern at the time was simply 

keeping the pilot warm. However, the increasing use of supercharged engines during the 

late 1920s led to the first serious studies into 

the physiological effects of altitude. As aircraft 

became capable of climbing above 30,000 feet, 

the concern was no longer how to keep the 

aviator warm but how to provide him oxygen 

and protect him from reduced pressure.2

The first known serious concept for a pressure 

suit came from Fred M. Sample of Jacksonville, OR. On July 16, 1918, Sample received 

U.S. Patent 1,272,537 for his “Suit for Aviators.” Being a smart inventor, never claiming 

an original item, he instead claimed “certain 

new and useful improvements.” In particular, 

he expected the suit could supply oxygen for 

aviators or travelers crossing high mountains. 

The full suit included a metal (although 

Sample indicated any suitable material could 

be used) helmet split vertically, hinged on one 

side, and latched on the other. The helmet was 

attached to the suit via bolts “or other securing 

elements” and had an oxygen hose connected 

to its back. Under the outer coveralls was 

an inflatable bladder that provided counterpressure to the chest. The suit buttoned up the 

front like single-piece long underwear and did 

not include integral gloves or boots, terminating instead with elastic cuffs at the wrists and 

ankles. Conceptually, it was similar to what 

others would ultimately build, but there is no 

record that Sample ever fabricated his suit.3

That brings the story to the other side of 

North America.

EARLY PRESSURE SUITS

It seems that Massachusetts has an indelible 

link to pressure suits. The David Clark 

Company, an entity that will play a remarkable role later on, was founded only 50 miles 

from where the story nominally begins.

Four years before David M. Clark founded 

the company that would bear his name 

in Worcester, MA, Mark Edward Ridge 

(1906–1962) resided in nearby Dorchester 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

26

and aspired to do great things. Before he did, 

however, Ridge would try a meaningless stunt. 

On January 16, 1931, he parachuted out of 

an airplane 2,000 feet above the Charles River. 

Oddly, at the time, Massachusetts had a law 

prohibiting anybody from jumping out of 

an otherwise perfectly good airplane, and the 

police promptly arrested Ridge, who eventually received a suspended sentence.4

Just two days after the court sentenced 

Ridge, on May 27, 1931, Auguste Piccard 

(1884–1962), a Swiss professor of physics 

at the University of Brussels, and his assistant, 

Charles Knipfer, reached a record altitude of 

51,775 feet over Augsburg, Germany, becoming the first humans to venture into the stratosphere. Their balloon, designated CH-113, 

was little more than a rubberized cotton gasbag 

with a 7-foot-diameter pressurized gondola that 

Piccard designed to combat the effects of high 

altitude. Funded by King Albert’s Fund for 

Scientific Research, the pair studied the intensity of cosmic rays using a small electroscope. 

About 15 hours after ascending, the balloon 

settled on the glacier above the village of Ober 

Gurgl in the Austrian Tyrol region.5

 Ultimately, 

Piccard made 27 balloon flights, setting a final 

record of 72,177 feet. They were altitudes that 

airplanes of the day could not touch.

Ridge also wanted to set a record. However, 

he believed that pressurized gondolas were 

too heavy to exploit the full performance of 

balloons, so he decided to use an open basket. 

Although he apparently did not understand 

the physiology behind the concept, Ridge 

knew he would need to surround his body 

with pressure. Lacking a pressurized gondola, 

he concluded a pressure suit would serve the 

same purpose. Ridge was certain he had happened upon a crucial idea and began searching for a patron. Repeated correspondence 

with the U.S. Army and U.S. Navy brought 

continued disappointment. Ultimately, at the 

suggestion of Dr. Timothy Leary,6

 the Boston 

medical examiner, Ridge contacted Dr. John 

Scott Haldane, Professor of Metallurgy, Gasses, Liquids, and Respirations at the University 

of Oxford, England, seeking assistance.7

Haldane, along with his son John Burdon 

Sanderson “Jack” Haldane (1892–1964), had 

spent 30 years experimenting with a small 

pressure chamber to determine the reason 

behind decompression sickness in deepsea divers. In 1908, Haldane and Dr. John 

G. Priestly published the first meaningful 

decompression tables for divers, which 

the Royal Navy subsequently adopted for 

service.8 In 1911, Haldane led an expedition 

up Pikes Peak, CO, to study the effects of 

low barometric pressure, and he concluded 

that a pressure suit would eventually be 

needed by flyers attempting to reach high 

altitudes. World War I distracted Haldane, 

who concentrated on the development of 

oxygen equipment, but in 1922, the professor 

clearly described a “stratosphere flying suit”9

developed in collaboration with Priestly.

At the time, Haldane was working with 

Sir Robert H. Davis10 of Siebe Gorman & 

Company to develop improved deep-sea diving suits. Siebe Gorman was the preeminent 

diving equipment makers of the day, and the 

company made a range of different diving 

helmets that could be identified by the number of bolts (6, 8, or 12, depending on the 

operating depth) used to attach the helmet to 

the collar of the suit.11 Diving suits had gone 

through a revolution during the mid-1800s, 

much as aviation pressure suits would in the 

1950s. The earliest diving suits were nothing 

more than vests with separate helmets held 

in place by just their weight. Many divers 

drowned because they moved in a way that 

allowed water to enter the helmet. One diver, 

George Edwards, suggested bolting the helmet 

to the breastplate of a full suit, making a truly 

watertight ensemble. Edwards encouraged 

Augustus Siebe to produce the design, and it 

was the start of a long and successful series of 

diving suits from the company.12

Less than a month after their initial contact 

with Ridge, Haldane and Davis had constructed a hypobaric protection suit by substantially altering one of their diving suits. 

Like the diving suit it was derived from, 

Ridge’s garment was made of rubber and canvas, sewn together into an airtight full coverall 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

27

Although undoubtedly not Mark Ridge’s suit, this example of 

a Haldane-Davis full-pressure suit shows that Siebe Gorman 

was certainly on the right track. The suit is tight fitting, and 

the straps on the torso are likely to keep the suit from ballooning under pressure. 

National Archives College Park Collection

with gloves and boots (minus the lead weights 

used by divers). A modified brass diving 

helmet covered the head. Ridge left Boston 

for London as soon as Haldane confirmed the 

suit was ready. On November 16, 1933, Ridge 

donned the suit and became, apparently, the 

first human to be tested wearing a pressure 

suit in an altitude chamber. Haldane lowered 

the pressure to a simulated 50,000 feet altitude (87 mm Hg) and Ridge suffered no ill 

effects. Two weeks later, on November 29, 

1933, Ridge used a suit pressure equivalent to 

approximately 42,000 feet (133 mm Hg) at 

a chamber pressure equivalent to 83,500 feet 

(17 mm Hg); the entire test had taken about 

an hour, with at least a few minutes at the 

maximum altitude.13

The London Daily Mail reported the tests, 

and the British Air Ministry quickly expressed 

interest in the suit. Ridge tried to persuade the 

Ministry to supply an open-basket balloon for 

flight tests in the stratosphere, but ultimately 

the British declined. The denial apparently had 

little to do with concerns over possible injuries 

to Ridge, but rather it was based on the likelihood the balloon would drift over Europe and 

that the Haldane-Davis “stratosphere flying 

suit” would fall into German hands.14

Ridge brought his suit back to the 

United States and quickly realized a flaw in 

the tests in London. Although they demonstrated that the suit provided protection from 

the low pressure at high altitude, the tests had 

not simulated the cold temperatures in the 

stratosphere. In response, Ridge designed an 

insulating garment he could wear under the 

suit. Along with Samuel Ring, a Boston aluminum foil dealer, Ridge made a set of long 

underwear made up of 12 alternating layers 

of aluminum foil and cotton cloth. Gloves, 

socks, and a head covering completed the 

ensemble. The chamois facemask had three 

holes: one for each eye and one for the mouth. 

A set of goggles covered the eyes and a primitive oxygen mask covered the mouth.

The Liquid Carbonic Corporation in 

Cambridge, MA, agreed to support a test of the 

suit, largely to obtain the publicity such a stunt 

would bring. The company lined a steel tank 

with 1,000 pounds of dry ice, and on March 8, 

1934, Ridge entered the tank. Despite carrying 

a small tank of breathing oxygen, carbon 

dioxide gas quickly subdued Ridge. The failure 

was traced to the oxygen mask, which did not 

seal well. By the time Ridge and Ring could 

repair it, Liquid Carbonic had a change of 

heart and refused to allow a second test. For a 

while, Ridge gave up.15

Two years later, on March 25, 1936, Dr. Karl 

T. Compton, renowned physicist and president 

of the Massachusetts Institute of Technology, 

wrote a letter endorsing Ridge’s pressure suit 

to Maj. Gen. Oscar Westover, the chief of the 

U.S. Army Air Service.16 Apparently, Ridge 

convinced Compton to support his cause 

based largely on grossly exaggerated claims of 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

28

his tests at Siebe Gorman and Liquid Carbonic. 

By this time, Wiley Post had already made his 

record-attempting flights with an operating 

pressure suit, and the Army was well aware of 

the technology since Post had tested his suit in 

an altitude chamber at Wright Field, OH. The 

Army researchers were more than willing to test 

Ridge’s suit, but Westover overruled them for 

unknown reasons.17

Ridge subsequently wrote to Louis A. Johnson, 

the Assistant Secretary of War, and finally to 

President Franklin Delano Roosevelt, neither 

with any success. Without support from the 

military and unable to raise sufficient financial 

support for the cost of his balloon, Ridge could 

not put his suit to actual use. The courts judged 

him insane in 1942 and Ridge never again 

saw the outside of an asylum. Mark Edward 

Ridge died on April 16, 1962, at the age of 56, 

without realizing his dream of flying into the 

stratosphere in an open balloon.18 Nevertheless, 

he lays claim to having, with the able assistance 

of John Scott Haldane and Sir Robert Davis, 

conceived and built the first full-pressure suit.

WILEY POST AND THE WINNIE MAE

Despite the dreams of Ridge and the pioneering efforts of Haldane and Davis, American 

adventurist Wiley H. Post (1898–1935) 

lays claim to being the first to actually use 

a full-pressure suit. Post was fascinated by 

the Wright Brothers as a child and by the 

age of 14, reportedly, had decided to become 

an aviator. It was not as easy as it sounded. 

His aviation career finally began at age 26 as a 

parachutist for the Burrell Tibbs & His Texas 

Topnotch Fliers flying circus. After making 

91 jumps, Post decided the career path did not 

provide sufficient funds to pursue his real passion of flying, and he went to work as an oil 

rigger in Seminole, TX. On his second day of 

work, October 1, 1926, an accident cost him 

his left eye, but he used the $1,698 settlement 

to buy his first aircraft—a wrecked Curtiss 

JN-4 Jenny that he subsequently rebuilt.19 In 

August 1928, Post applied for a commercial 

pilot’s license, which presented the Department of Commerce with something of a quandary given the loss of Post’s left eye. The flight 

surgeon agreed that Post’s depth perception 

was better than most people with two eyes, 

and eventually the Government issued Post a 

waiver that allowed him to obtain a commercial ticket.20

Post used the Jenny for stunt flying, making 

a better living than he did as a parachutist. 

While performing in Ardmore, OK, Post met 

Mae Laine, and later the same day, the couple 

was married. It did not take long for Post to 

discover that he could not support a wife by 

stunt flying. During an air show, Post heard 

that millionaire oilman Florence C. “F.C.” 

Hall, had recently purchased an airplane and, 

despite never having previously met the man, 

Post wrangled a job as his personal pilot. After 

a couple of years, Hall decided to sell his airplane, and Post went to work as a test pilot for 

Lockheed Aircraft Company in Burbank, CA. 

There, he fell in love with the Vega.21

Designed by John K. “Jack” Northrop and 

Gerard “Jerry” Vultee, both of whom would 

later form their own aircraft companies, the 

Vega broke ground by using a full monocoque 

fuselage and cantilever wings. The laminated 

wood fuselage skin was manufactured using a 

large concrete mold, and the fuselage halves 

were then nailed and glued over a previously 

made wooden rib frame. The metal wing was 

mounted in a streamlined faring on top of 

the fuselage and power came from a single 

225-horsepower (hp) Wright J-5 Whirlwind 

radial engine.22

The first Vega 1 made its maiden flight on 

July 4, 1927. The airplane spanned 41 feet 

across, was 27.5 feet long, and had a gross 

weight of 4,200 pounds. It could cruise at a 

then-fast 120 miles per hour (mph) and had 

a top speed of 135 mph. However, airlines 

quickly decided that a 4-passenger airplane 

was not economical, and most of the 68 Vega 

1s went to private owners. Despite its commercial failings, the airplane was fast: in the 

1928 National Air Races in Cleveland, OH, 

Vegas won every category. In 1929, Lockheed 

introduced the Vega 5, which, used the 

450-hp Pratt & Whitney R-1340 Wasp engine 

and carried six passengers. Equipped with a 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

29

streamlined NACA engine cowling, cruise 

speed increased to 155 mph and top speed to 

165 mph. Unfortunately, its economics were 

not much better, and almost all of the 64 Vega

5s went to private owners as well. Regardless 

of its perceived failings as an airliner, the Vega 

became famous for its use by a number of 

now-legendary pilots who were attracted to th

rugged and long-range design. Amelia Earhart 

used a Vega to become the first woman to fly 

solo across the Atlantic, and Wiley Post would 

fly his around the world, twice.23

Post’s enthusiasm for the Vega was contagious,

and Hall agreed to purchase one if Post would

fly it for him. Post agreed, on the condition 

that he could enter it in the National Air Race

Derby from Los Angeles to Chicago. Hall 

thought it was a good plan. On August 23, 

1930, the gloss-white Vega with purple cheat 

lines landed at the Curtis-Reynolds Airport 

just north of Chicago after a 9-hour, 9-minut

record flight. Hall was ecstatic and promptly 

gave Post the $22,000 airplane. It was the 

beginning of worldwide fame for Wiley Post, 

and the airplane named Winnie Mae.

24

In 1929, the German airship Graf Zeppelin

(LZ127) circumnavigated Earth in 21 days, 

5 hours, and 31 minutes, making a journey 

that covered 30,831 miles.25 Wiley Post was 

certain a fixed-wing aircraft could do the 

same trip much faster. With Australian 

Harold Gatty, Post took the Winnie Mae

e 

e 

around the world in 8 days, 15 hours, and 

51 minutes, earning the pair a ticker-tape 

parade in New York City and lunch at the 

White House. Two years later, Post equipped 

the Winnie Mae with an autopilot and radio 

compass, then proceeded to fly around the 

world solo in 7 days, 18 hours, and 49 minutes, earning himself a second ticker-tape 

parade. The Fédération Aéronautique Internationale (FAI) awarded Post the Gold Medal 

and the International League of Aviators 

(Ligue Internationale des Aviateurs) presented 

him with the Harmon Trophy.26 More important, perhaps, to Post was an observation he 

made during these flights: the higher you fly, 

the faster you go. 

During 1933, Melbourne, Australia, was 

preparing to celebrate its centennial in 

October 1934. To properly mark the event, 

Sir MacPherson Robertson (1859–1945), 

an Australian philanthropist, entrepreneur, 

and founder of the Mac Robertson Steam 

Confectionery Works,27 offered a cash prize 

of £10,000 (about $50,000 at the time, or 

$750,000 today) to the winner of an air race 

between Mildenhall, England and Melbourne, 

Australia, via a designated course over Baghdad, 

Allahabad, Singapore, and Darwin.28 It was a 

race Post could not resist. However, Post was 

also well aware that much better aircraft had 

emerged during the 5 years since Winnie Mae 

was built. To compensate, Post intended to 

fly in the thin air above 30,000 feet, taking 

advantage of the powerful tailwinds he 

believed existed at high altitudes.29

Writing in the 1850s, the pioneering American 

balloonist John Wise (1808–1879) theorized 

there was a “great river of air which always 

blows from west to east” that could take his 

balloon across the Atlantic.30 Wise made over 

450 flights during his lifetime and was responsible for several innovations in balloon design. 

Unfortunately, Wise mysteriously disappeared 

on a trip in high winds from East St. Louis on 

September 28, 1879, before he had made any 

progress in further defining his theory. 

Based on his observations during his aroundthe-world flights, Post was certain that Wise 

was correct and believed that “high winds,” 

as he called them, existed in the stratosphere. 

If he could find these, they could carry the 

Winnie Mae at greatly increased speeds. These 

winds are now known as the “jetstream.” 

During the early 1930s, the physiological 

aspects of long periods at altitude were not 

well understood, and neither the engines nor 

propellers of the day were capable of propelling a meaningful airplane at high altitudes 

for any length of time. There was an ongoing 

competition, mostly in Europe, to set altitude 

records, but these were simple up-and-down 

flights that provided minimal exposure to the 

effects of high-altitude flight. Nobody was 

talking seriously about long-distance flights 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

30

above 30,000 feet or even 20,000 feet—except 

Wiley Post.31

Despite his lack of knowledge of the subject, 

Post knew that he needed pressurization to 

keep him alive. Oxygen masks of the period 

were ineffective at any serious altitude, 

and physiologists had not yet discovered 

the concept of pressure breathing. Post 

realized that it was impossible to pressurize 

the wooden fuselage of Winnie Mae, and 

incorporating a separate pressurized cabin into 

the Vega would be prohibitively expensive. 

Running out of options, Post decided on 

the only other course available—he would 

have to pressurize himself.32

Post’s pressure suit seemingly had no connection to the efforts of Mark Ridge around the 

same time, and it is not clear if Post knew 

about Fred Sample or John Scott Haldane’s 

theoretical suggestions. In any case, the suit 

that Post needed was quite different than the 

one developed by Haldane and Davis. Because 

of its deep-sea roots, the Haldane-Davis suit 

was stiff, and even simple movements were 

difficult to perform when the suit was inflated. 

This would not have been a major issue for 

Ridge since flying an open-basket balloon 

requires little movement; mostly it involves 

quietly sitting and waiting. Flying an airplane, 

on the other hand, requires the pilot to move 

his legs, arms, and fingers almost constantly. 

This would become one of the defining 

requirements, and difficulties, in the development of pressure suits.

In the spring of 1934, Post asked for assistance 

from his friend Jimmy Doolittle, who had 

joined Shell Oil Company as director of aviation and might have been capable of making 

a pressure suit. Doolittle referred him to the 

Research Aviation Department of the B.F. 

Goodrich Company in Los Angeles. Post first 

visited the Goodrich plant on April 6, 1934, 

and requesting, “a rubber suit which will 

enable me to operate and live in an atmosphere 

of approximately twelve pounds absolute 

[5,500 feet altitude equivalent]. I expect to fly 

through rarefied areas where the pressure is as 

low as five pounds absolute [27,000 feet]. The 

temperature incident will be taken care of by 

heating the air from the supercharger by coiling it around the exhaust manifolds.”33 A new 

engine supercharger would provide compressed 

air for suit pressurization and ventilation. 

Goodrich assigned William R. Hucks as the 

project engineer for the development of the 

suit, with John A. Diehl and J. Stevens assisting in its fabrication. Progress was agonizingly 

slow, primarily because none of the Goodrich 

personnel were familiar with making clothes, 

so Post eventually asked Goodrich to hire a 

professional tailor to make the initial patterns. 

Goodrich fabricated the first suit from 6 yards 

of rubberized parachute cloth with two layers 

glued together on a bias to minimize stretch. 

The sleeves were carried to the neckline in 

a raglan cut, and the suit included pigskin 

gloves and rubber boots. The two-piece garment (shirt and trousers) sealed at the waist 

using a Duralumin metal belt.34

At the same time, Lowell Peters, a metalworker in Los Angeles, fabricated an aluminum helmet for Post. It generally resembled a 

welder’s helmet, weighed 3.5 pounds, and had 

a 2.75- by 7.5-inch rectangular visor made 

of two layers of clear plastic. A bulge covered 

each ear to accommodate headphones and 

Post could eat when the suit was unpressurized by opening a small door over the mouth. 

Addressing another area that would long vex 

designers, front and rear handles on the lower 

edge of the helmet allowed Post to tie it down 

to the suit to keep the helmet from rising 

when the suit was pressurized. The estimated 

cost of the pressure suit and helmet was $75 

(an unbelievable $1,500 in 2009).35

Goodrich tested the suit by pressurizing it to 

5 psi. A major flaw quickly became apparent: the pressurized suit would not allow the 

wearer to raise his arms, which hang uselessly 

at his sides. Hucks quickly reworked the arms 

of the suit and subsequent tests showed the 

arms could be raised with considerable effort. 

Some leakage was detected near the waist 

joint, but it was considered acceptable, so 

Goodrich shipped the suit to Post in Ohio.36
31

Wiley Post shows off his inflated full-pressure suit in front 

of the Winnie Mae. Note the wingnut on Post’s shoulder, 

just behind the helmet. The oxygen generator is on the 

ground next to Post, connected to the left side of the visor. 

The position of Post’s arms shows the relative stiffness of the 

inflated suit, something that would hamper pressure suit 

development for another 50 years. 

Courtesy of Chevron Corporation Archives

Post was at Wright Field consulting with 

the Engineering Division of the Army Air 

Corps. In particular, he dealt with the Equipment Branch, which was responsible for 

evaluat-ing flying suits, goggles, and methods 

of protecting aircrew against cold. Wright 

Field had an altitude chamber large enough 

(10 feet high and 9 feet in diameter) for a 

man, although the Army mostly used it to 

check altimeters. This chamber had originally been installed at the Medical Research 

Laboratory at Hazelhurst Field in Mineola, 

Long Island, NY. In March 1921, a fire 

destroyed much of the laboratory, but, 

fortunately, the chamber survived.37

During the 1930s, the Army Air Corps was 

an organization in search of an identity. 

Funding was at an all-time low, and service 

only had several hundred operational 

airplanes, most hopelessly obsolete. Wiley 

Post and his pressure suit seemed the stuff 

of science fiction when he showed up and 
32

The Post pressure suit was 

fairly flexible when not 

pressurized, allowing Post 

a reasonable amount of 

movement and comfort. 

Note the nipple below the 

left knee where air exited 

the suit; normally this was 

attached to a regulator and 

pressure gauge. Given that it 

was the first real attempt at 

building a workable pressure 

suit, the Post garment 

worked remarkably well. 

NASA

asked for assistance in testing the garment. On 

June 23, 1934, while Post was pressurizing 

the suit to a differential pressure of 2 psi as a 

demonstration for the Army engineers, a piece 

of reinforcing tape failed, effectively ending 

the effort. Nevertheless, according to a press 

report in The Cleveland News, Post apparently 

made at least one flight in the Winnie Mae

while wearing the unpressurized suit, most 

likely to check mobility and vision while 

wearing the ensemble.38

Post took the damaged suit to the Goodrich 

plant in Akron, OH, where he met Russell 

S. Colley (1899–1996), who was intimately 

familiar with using rubber products in aeronautical applications. Colley had been born 

in 1899 in Stoneham, MA. As a young man, 

Colley displayed excellent mechanical skills 

but told his parents that he wanted to design 

women’s clothing. Not agreeing with this 

career choice, his parents persuaded him to 

enroll at the Wentworth Institute of Mechanical Engineering. In 1928, Colley accepted a 

position with the B.F. Goodrich Company 

as a mechanical engineer and was part of 

the team that developed de-icing boots for 

aircraft.39 Goodrich researchers determined 

that gluing an inflatable rubber “boot” on the 

leading edge of an aircraft’s wing (and empennage) and alternately inflating and deflating 

it, caused ice to break off. In December 1931, 

Colley and Wesley L. Smith, a former Air 

Mail Service pilot who was then operations 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

33

manager for National Air Transport, used 

a Travel Air 6000 mail plane for a series of 

flights into known icing conditions to test 

the Goodrich de-icing boots. Colley sat on an 

orange crate in the mail compartment of the 

airplane and used a bicycle pump to inflate 

the tubes, alternating from one tube to the 

other by means of a manually operated valve. 

In late 1932, William S. “Billy” Brock flew 

further tests using a Goodrich-owned Lockheed Vega named Miss Silver Town. By 1934, 

the Goodrich system was becoming standard 

equipment on American airliners and many 

lower-speed aircraft still use similar systems 

(they are not effective on high-speed aircraft 

that require precise airfoil shapes).40

Meanwhile, the MacRobertson Race was only 

3 months away. Colley developed a new suit 

that would work with the original helmet, 

although he installed an oxygen hose fitting 

below the visor. Post entered the two-piece 

suit through the waist, and two large metal 

plates sealed the torso. Flexible elbow and 

knee joints allowed improved limb movement 

when the suit was inflated.41

In a turn straight out of a slapstick comedy 

of the era, the first time Post tried on the new 

suit, he became stuck in it. Partly, this was 

because of the hot and humid weather that 

embraces Dayton in July (and the lack of 

air conditioning in 1934), but it was mostly 

because Post had gained several pounds since 

he had been measured for the original suit and 

Colley had used the same patterns. The only 

way to extract Post was to cut the suit into 

pieces. Nevertheless, Colley and Post learned a 

great deal concerning the behavior of the suit 

under static pressure.42 By now it was obvious 

that Post would not have a suit ready for the 

MacRobertson Race.43

After the unexpected turn of events with the 

second suit, in late July 1934, Post and Colley 

decided to fabricate an entirely new suit and 

helmet. For the third suit, Colley suggested 

two separate layers: an inner, body-contoured 

rubber garment that would contain gaseous 

oxygen under pressure, and an outer, three-ply 

cloth garment, made to resist stretching and to 

hold the rubber suit to Post’s body contours. 

The third suit used a differential pressure of 

7.25 psi (0.5 atmosphere), 2 psi greater than 

the first two suits.44

Colley began by taking precise measurements 

of Post sitting in a position that mimicked 

what was needed to fly the Winnie Mae. He 

made cardboard limb and trunk forms and 

used them to cut the fabric for the outer layer. 

Colley formed the inner pressure layer by 

pouring liquid latex over sheet-metal forms. 

Thanks to the new set of measurements, this 

suit fit much better. Since Colley formed 

the suit for the sitting position, Post walked 

slightly bent over while wearing it, although 

he could stand straight with some effort. 

Unlike the first two suits, which Post entered 

from the waist, an enlarged neck opening 

provided entry to the third suit. The new 

helmet bolted to a metal collar after the pilot 

was securely in the suit. Post could not reach 

the wing nuts in the back of the helmet and 

required assistance to don and doff the suit.45

The new helmet was considerably improved 

and included a large round window, made of 

glass instead of plastic, that Post could easily remove since the faceplate edge had large 

notches to accommodate gloved fingers. The 

helmet was wide enough to accommodate 

earphones and did not have the bulges of the 

first helmet. Oxygen entered through a port 

just to the left of the window (Post had the 

patch over his left eye) to defog the glass. An 

outlet to the right of the window vented the 

helmet. A valve, attached to a regulator and a 

pressure gauge, just below the left inner knee 

controlled outflow from the suit. 

After a detailed evaluation and several static 

inflation tests, on August 27, 1934, Post made 

the first altitude chamber test of a pressure 

suit in the United States. As the simulated 

altitude passed 18,000 feet, Post screwed in 

the glass window and the suit began to inflate. 

Everybody immediately noticed the helmet 

began to rise off Post’s head, and Colley noted 

the need for some type of restraint. However, 

the liquid oxygen system was not providing 

enough oxygen, and after 27 minutes, as the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

34

The Winnie Mae while it 

was sponsored by the Pure 

Oil Company. The Lockheed 

Vega was 27.75 feet long, 

spanned 41 feet, and had 

a gross weight of just over 

4,000 pounds. Lockheed 

designed the airplane to 

cruise at 140 mph and fly 

725 miles at altitudes under 

20,000 feet, figures that Post 

routinely exceeded. 

Courtesy of Chevron 

Corporation Archives

chamber passed 21,000 feet, Post signaled he 

needed to descend.46

Afterward, Colley added bandolier-type cords, 

which were looped around the helmet and 

attached to a semi-rigid, 8-inch-wide sling 

that Post sat on. On August 29, Post reached 

23,000 feet during 35 minutes in the chamber 

and by all accounts, was satisfied with the performance of the suit.47

On the following day, Post took the Winnie 

Mae on the first flight with an operating pressure suit. On September 5, 1934, Post reported 

that he reached 42,000 feet over Chicago 

during an altitude-record attempt sponsored 

by the Pure Oil Company (now part of Chevron) as part of the Chicago World’s Fair.48 The 

flight revealed that the pressure suit worked 

well, although some minor adjustments 

would be necessary, including extending the 

control stick to allow the inflated glove to 

better grasp it. The maximum pressure differential on the flight was 3 psi.49

From Chicago, Post called Will D. “Billy” 

Parker, the aviation director for Phillips 

Petroleum.50 After explaining that the Pure 

Oil Company and other sources of financing 

for his stratosphere experiments were drying 

up, Post asked if Parker could interest Phillips 

in sponsoring his flights. Post soon flew the 

Winnie Mae to Bartlesville, OK, to meet with 

Frank Phillips, sealing a deal.51

Post used his pressure suit on eight or nine 

flights at Bartlesville, reportedly reaching 

50,000 feet. However, it takes two independent means to verify a record; in this 

case, those sources of verification were two 

barographs installed in the aft fuselage by the 

National Aeronautic Association, the U.S. 

representative to the FAI. Unfortunately, the 

National Bureau of Standards reported that 

both barographs failed on all but one flight 

on which one barograph failed and the other 

recorded only 38,000 feet after corrections for 

atmospheric conditions. No record for Post.52

Despite the setback, Post began to prepare for 

a coast-to-coast stratospheric flight. He flew 

to Burbank, CA, for one further modification to Winnie Mae: eliminating the landing 

gear to reduce drag. At the Pacific Airmotive 

Hangar in Burbank, Jimmy Gerschler and 

the soon-to-be-legendary Clarence L. “Kelly” 

Johnson—another person who would have 

a major influence on later events—designed 

new main landing gear that could be jettisoned via a handle in the cockpit. A spruce 

timber was glued to the fuselage for use as a 

skid during landing, and a strong V-shaped 

support was placed in front of the lower 

engine cylinders that ran to the lower front 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

35

edge of the NACA cowling. Post made five 

flights at Burbank, all using the pressure suit 

in preparation for his stratospheric flight.53

Transcontinental and Western Airlines (TWA)

joined Phillips Petroleum as sponsors of the 

flight and arranged for Post to carry airmail, 

including special stamps bearing his picture 

and the inscription “First Air Mail Stratosphere Flight.”54 On February 22, 1935, Post 

took off, but the engine began to leak oil 

after only 31 minutes, forcing Post to land 

on Muroc Dry Lake, later home to Edwards 

Air Force Base, only 57 miles from Burbank. 

Since Post could not doff his pressure suit helmet by himself, he walked about 400 yards to 

ask H.E. Mertz for assistance; Mertz promptly 

fainted. A few days later, Post announced that 

it was not a broken oil line that had foiled his 

flight, but rather emery dust that mechanics 

found in his engine. Someone had deliberately 

sabotaged the flight.55

After repairs, Post tried again. On March 5, 

he got as far as Cleveland before his oxygen 

ran out. After climbing out of the airplane and 

removing the pressure suit, Post learned that 

he had flown 2,035 miles in the record time of 

7 hours and 19 minutes. The Winnie Mae had 

averaged a ground speed of 279 mph, approximately 100 mph faster than she should have 

flown. Two more flights followed, the first ending at Lafayette, IN, (1,760 miles) on April 14, 

after the external supercharger failed, and the 

second ending at Wichita, KS, (1,188 miles) 

on June 15 after a piston burned-through.56

Post decided the Winnie Mae was too old and 

tired for further attempts. He had nonetheless proved the practicality of a pressure suit, 

spending about 30 hours in the stratosphere. 

The Winnie Mae approached ground speeds 

of 340 mph, more than a third faster than the 

airplane’s normal maximum speed. The Smithsonian Institution subsequently purchased the 

Winnie Mae, which is currently on display 

at the Udvar-Hazy Center near Washington 

Dulles International Airport in Chantilly, VA. 

The helmet from Post’s first suit, and his entire 

third suit, are also in the collection of the 

National Air and Space Museum.

On August 15, 1935, just 2 months after his 

last flight in the stratosphere, Post made his 

final takeoff, in a bastardized Lockheed OrionExplorer seaplane in Alaska. The engine 

stopped at a low altitude, and the ensuing 

crash killed Post and his passenger, humorist 

Will Rogers. Post was only 36 years old but 

had made an indelible mark on aviation.57

INTERNATIONAL EFFORTS

The 1930s saw considerable international 

competition to set altitude records, and this 

spurred the development of several pressure 

suits. It should be noted that almost all of 

these were simple up-and-down flights that 

Wiley Post peers over the 

top of the Winnie Mae 

while wearing his pressure 

suit. Given it was the first 

of its type to be used operationally, the Russell Colleydesigned garment worked 

remarkably well. 

Courtesy of Lockheed 

Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

36

Post tried numerous times 

to set an altitude record, 

but it was just not to be. 

Despite his failure at this one 

endeavor, Post remains one 

of the early aviation legends.

Courtesy of Chevron 

Corporation Archives

spent little time at high altitude and did not 

put the same stress on aircraft, pressure suits, 

or pilots as does cruising in the stratosphere. 

In addition to the Americans and British, the 

French, Germans, Italians, Russians, and Spanish developed high-altitude pressure garments, 

all of which would later be called full-pressure 

suits. There were many objectionable features 

to these early suits since they prevented evaporation of perspiration, greatly restricted mobility when pressurized, and were heavy and 

bulky.58 Nevertheless, they worked, mostly.

The Italians developed a suit in 1933 to 

allow Regia Aeronautica pilots to set altitude 

records using several specially built open 

cockpit Caproni Ca.161 airplanes. These were 

conventional biplanes based on the Ca.113 

with staggered wings of equal span. The suit, 

designed by Capt. Cavallotti, was made of 

several layers of canvas and rubber, with a 

metal collar that attached to a cylindrical 

metal helmet with square viewing ports. 

The electrically heated suit used metal alloy 

restraint devices, including a breastplate, 

to prevent the fabric from ballooning. In 

1934, Baronessa Carina Negroni reportedly 

wore the suit to climb to 50,583 feet, 

undoubtedly becoming the first woman to 

use a pressure suit. Despite several reports 

that the Italians, including Negroni, used the 

suit to set records in the mid-1930s, the FAI 

database does not reflect this. It is likely that 

the reported flights took place but were not 

recognized by the FAI for various reasons.59

Ultimately, Italian Col. Mario Pezzi took the 

altitude record from the British on October 

22, 1938, when he climbed to 56,046 feet 

above Guidonia Montecelio, Italy. He used 

a modified Caproni Ca.161bis that had 

extended chord wings and a supercharged 

engine driving a four-blade propeller. 

However, Pezzi did not use a pressure suit 

on this flight since the Ca.161bis had a 

pressurized cockpit.60

In France, Dr. Paul Garsaux developed a suit 

during the mid-1930s with the backing of 

the Potez Airplane Company. Garsaux was a 

pioneer of aviation medicine in France and 

director of the Paul Bert Aeromedical Center 

at Le Bourget. During World War I, Garsaux 

developed an aviation oxygen system that used 

an aluminum mask shaped to conform to 

the wearer’s face, with inflatable face-sealing 

bladders to ensure a tight seal. The mask had 

a built-in heating system to avoid the exhaled 

water vapor turning to ice.61

The first Garsaux suit, codeveloped with 

Dr. Rosenstiel from the French Navy, 

used two layers of linen, but this proved 

unsatisfactory and was soon replaced by 

laminated layers of silk and rubber doped 

with acetone to make it airtight. Large 

shoulder joints allowed arm movement and 

a set of gloves was spring-loaded into a 

closed-fist position. A round Duralumin 

helmet had rectangular eye openings made 

of two layers of glass with an air space in 

between them to prevent fogging, although 

the mask also had an electric defogging 

system. At only 31 pounds, the French suit 

was lighter than the one used by Wiley Post.62
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

37

Garsaux demonstrated the suit at Le Bourget in June 1935. Most likely, Marie-Louise 

“Maryse” Hilsz wore the suit when she set the 

female altitude record of 46,949 feet on June 

23, 1936, flying a Potez 506 over Villacoublay, 

France. The climb took 36 minutes in the 

770-hp biplane. Similarly, Georges Détré likely 

used the suit when he climbed to 48,698 feet 

over Paris in a Potez 506 on August 14, 1936, 

although no documentation was available to 

confirm he used the suit.63 Unfortunately, all of 

Garsaux’ work and records were destroyed by 

German bombs on June 3,1940, and by October all further aeromedical research in France 

had been halted by the Nazi occupiers.64

As might be expected, the Germans were not 

idle. In 1935, Dräger-Werke AG in Lübeck, 

Germany, began developing a hard-shell, fullpressure suit for the German Air Ministry. 

Dräger was familiar with technologies that 

involved pressure, including beer-tap systems 

that used compressed carbon dioxide, medicinal compressed-oxygen systems, anesthesia 

machines, and aviation-oxygen systems. Perhaps most famously, the company produced 

the Dräger underwater breathing apparatus 

used by the Germans during World War II.65

The requirements levied by the Air Ministry 

included being able to operate at an internal 

pressure of 11.8 psi (0.8 atmosphere) with a 

“three-fold safety factor.” The ministry wanted 

a suit that would fit a pilot 5 feet, 10 inches 

tall and permit “rapid dressing and undressing 

without additional help.”66 The suit needed to 

allow free movement of the arms, legs, and fingers to permit the pilot to fly the aircraft and 

provide the possibility of parachute escape. 

Electric heaters would protect against the cold 

at high altitude and prevent fogging of the 

visor. Dräger calculated that the required test 

pressure of 35.3 psi necessitated the use of a 

heavy material that “cannot readily be formed 

into a garment.”67 Nevertheless, the company 

produced a series of “hard suits” that looked 

much like medieval suits of armor.

Based on revised, relaxed requirements, the first 

Dräger full-pressure suit used laminated layers 

of natural silk cloth and rubber strengthened 

by an external layer of silk fishnet cord that was 

supposed to control the fabric’s tendency to 

balloon under pressure. The helmet, made of 

the same material, was integral to the suit, but 

under pressure the ballooning fabric pressed 

the visor painfully against the pilot’s forehead. 

Despite the silk cord, the entire suit ballooned 

unacceptably, so the engineers replaced the silk 

fishnet with steel wire and reduced the internal pressure to 4.4 psi (0.3 atmosphere). This 

helped somewhat, but the wire presented a 

safety hazard by catching on any protuberance 

in the cockpit. In addition, the suit elongated 

(head to feet) to the point that the pilot could 

no longer see out of the visor. Eventually, the 

idea evolved to using chainmail mesh, allowing a pressure of 11 psi (0.75 atmosphere), but 

this severely restricted mobility and ultimately 

proved unsatisfactory.68

One of the most difficult requirements faced 

by Dräger, and all future pressure suit developers, was how to provide sufficient mobility 

at the joints. Dräger started with a tube with 

longitudinal folds held in place with one longitudinal band. This provided, under pressure, a 

tube that was flexible in one plane, but it provided insufficient mobility. A careful analysis 

of pilot movements in the cockpit of large aircraft showed that the arms did not need a full 

range of movements; only the forearms needed 

to move enough to manipulate the control 

wheel and throttles. This led to the development of airtight ball-bearing socket joints used 

at the shoulders, biceps, elbows, and wrists. 

By 1942, Dräger was concentrating on aluminum hard suit designs pressurized at 11 psi 

that still offered satisfactory mobility. In June 

1942, Dräger demonstrated a hard suit to the 

Air Ministry; it was unacceptably heavy, difficult to walk in, and never became operational.69

In the meantime, on October 28, 1941, the 

Air Ministry ordered Dräger to develop an 

emergency descent suit. Unlike all earlier 

full-pressure suits designed to be the only 

protection for a pilot in an unpressurized 

cockpit, the get-me-down suit provided only 

short-term protection when an otherwise pressurized cockpit suddenly depressurized. If the 

cockpit suddenly depressurized as the result 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

38

These oft-published photos 

of the Dräger hard suit 

show that it was completely 

impractical as an aviation 

garment. Note the unusual 

gloves, where the thumb 

and forefinger are separate 

but the remaining fingers 

are grouped as in a mitten. 

The concept of a satisfactory 

hard suit has still not been 

realized, although NASA 

continues to experiment 

with them as exploration 

suits for journeys to the 

Moon or Mars. 

National Archives College 

Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

39

of battle damage or equipment failure, the 

suit would quickly inflate to 2.2 psi to protect 

the crewmember long enough to descend to a 

survivable altitude. The crewmember wore an 

ordinary oxygen mask inside a cloth helmet, 

and air from an engine-mounted compressor 

pressurized the suit when required. Ultimately, 

this helmet proved unsatisfactory and the Germans eventually settled on a completely clear 

plexiglass70 dome helmet, but this new helmet 

still used a separate oxygen mask inside it.71

The Luftwaffe experimental station (Erprobungsstelle) at Rechlin, Germany, tested a 

series of get-me-down models, but a flaw in 

the original logic quickly became apparent. 

Initially, the Luftwaffe viewed the suit as a 

method of keeping the crew alive after cabin 

pressure failed without regard of who would 

actually be flying the airplane. Unfortunately, 

the initial suits, when inflated, offered almost 

no mobility. This led to the development of 

ball-bearing joints, similar to those developed for the heavy hard suit, at the shoulder, 

elbows, and wrists. The final suit was made of 

rubberized silk and was entered through an 

enlarged neck opening, although work continued on a two-piece suit that was entered at the 

waist. Again, there is no evidence that the getme-down suit entered production.72

Oddly, in the summer of 1944, the German 

Glider Research Institute ordered Dräger to 

develop a rescue suit for use in gliders equipped 

This Dräger Model 8 get-me-down suit was possibly the 

most developed of the German suits. Note the large, clear 

plexiglass helmet. The pilot is not wearing his oxygen mask in 

this photo, but the shape of the helmet was partly dictated by 

needing to allow the pilot to move his head side to side within 

the helmet while wearing the mask. Pleats at the elbows and 

knees provided at least some measure of flexibility when the 

suit was pressurized. 

National Archives College Park Collection

with pressurized cabins. The pilot was to fly in 

a prone position, and the Institute indicated 

that freedom of movement under the 3.1-psi 

operating pressure was not a concern.73 There is 

no evidence that this suit was ever completed.

In Spain, Col. Don Emilio Herrera Linares 

built a full-pressure suit in anticipation of 

an open-basket balloon stratospheric flight 

scheduled for early 1936. Unfortunately, the 

Spanish Civil War intervened. Herrera chose 

the Republican side and cannibalized the 

rubberized silk suit to make rain ponchos for 

Republican troops. In 1939, Herrera fled to 

France, where he died in exile in 1967.74

The Herrera suit used an inner airtight garment covered by a pleated metallic frame 

with articulating joints for the shoulders, 

hips, elbows, knees, and fingers. When tested 

at the Cuatro Vientos Experimental Station, 

near Madrid, the suit’s pressurized mobility 

was found to be “thoroughly satisfactory” 

according to its inventor, although this 

was most certainly an overstatement based 

on experience with later suits. The helmet 

faceplate had three heated glass layers: one 

unbreakable, another with an ultraviolet filter,

and the outer one opaque to infrared. Initially

based on the cold atmosphere present at high 

, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

40

altitudes, Herrera included an electric heater 

in the suit. However, when Herrera tested the 

suit in an altitude chamber, he noticed that 

even at an ambient temperature of –110 oF, 

the temperature inside the suit climbed rapidly to 90 oF. A trained engineer, he soon realized that the task was not to warm the suit but 

rather to remove body heat by some method. 

Herrera called his stratospheric suit an escafandra estratonautica. Unfortunately, mostly 

because of the urgencies of war, the suit was 

never used in an airplane or a balloon.75

When declining to help Mark Ridge, the 

British Air Ministry concerns centered on the 

indeterminate flight paths of balloons, not 

on the Haldane-Davis suit itself. After Ridge 

returned to the United States, Dr. Gerald 

Struan Marshall, consultant and applied 

physiologist for the Royal Air Force, worked 

with Siebe Gorman to continue development, 

resulting in the procurement of several proto-

type suits. These two-piece garments used 

rubberized fabric fastened together with a 

metal and rubber belt at the waist. Instead 

of a metal helmet like Ridge and Post used, 

Siebe Gorman used a simple rubber fabric 

cover with a curved visor made of two layers 

of Celastoid. Pure oxygen pressurized the suit 

to a maximum 2.5-psi differential through a 

flexible tube attached to the right side of the 

faceplate. Exhaled air exited the left side of 

the faceplate into a chemical canister that 

dried the air and removed the CO

2

.

76

After World War II, the U.S. 

Army Air Forces issued a

“Translation of a Report on 

Development of a Pressure 

Suit” that contained this 

diagram of “the final model 

German pressure suit.” The 

suit is obviously a soft-suit 

but does not precisely match 

the description of any 

specific suit in the report. 

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

41

Squadron Leader F.D.R. “Ferdie” Swain77 used 

one of these suits to take a Bristol 138a to an 

altitude of 49,944 feet over Farnborough on 

September 28, 1936. The Bristol was an experimental all-wood monoplane intended specifically to capture the world’s altitude record. A 

43,000-foot oxygen-equivalent altitude was 

maintained in Swain’s suit because greater 

pressures reduced mobility and comfort to an 

intolerable degree. The suit performed satisfactorily, although Swain complained of some 

discomfort as the suit inflated and he found it 

difficult to move his arms and legs. However, 

as the pilot began to descend after his record 

flight, the faceplate began to fog over and he 

found it difficult to breathe. Unable to unzip 

his suit, Swain had to slice open his visor with 

a knife as he descended through 14,000 feet.78

Despite the problem, the FAI ratified this 

flight as a world record.79 On June 30, 1937, 

Flight Lieutenant Maurice James Adam wore 

a modified suit to set a record of 53,937 feet 

in the Bristol 138a. On this flight, the canopy 

failed and the Haldane-Davis pressure suit 

likely saved the pilot’s life.80

AEROMEDICAL PIONEERS 

Shortly after the first powered flight in 1903, 

scientific interest in the medical aspects of 

flight grew dramatically. It quickly became 

obvious that the aviation environment was 

very different from the environment on the 

ground. On the cusp of World War I, the 

War Department was aware of the need to 

improve the fitness and efficiency of military 

aviators to carry out combat operations. In 

1917, a Medical Research Board was chartered 

to investigate all conditions that affected the 

efficiency of pilots, determine the ability of 

pilots to fly at high altitudes, develop suitable 

apparatus for the supply of oxygen to pilots at 

high altitudes, and consider all matters relating to the physical fitness of pilots. This led to 

the establishment of the Army Signal Corps 

Medical Research Laboratory on January 18, 

1918, at Hazelhurst Field on the outskirts of 

Mineola, NY. The laboratory’s research scientists initially focused on developing pilot selection standards and understanding the effects 

on humans of exposure to high altitude.

Already, aeromedical scientists were well aware 

that the lack of oxygen (hypoxia) was the 

pivotal hazard encountered during flight. The 

effects of hypoxia had been investigated by 

Dr. Paul Bert (1833–1886), a French zoologist, physiologist, and politician, who carried 

out 670 separate experiments from 1870 to 

1878 dealing with the physiologic effects of 

altered atmospheric pressure. In 1874, Bert 

subjected two balloonists, Joseph-Eustache 

Croce-Spinelli and Henri-Theodore Sivel, to 

a chamber altitude of 23,000 feet to investigate the use of oxygen to prevent hypoxia. On 

April 15, 1875, Gaston Tissandier, a French 

chemist, meteorologist, and aviator, joined 

Sivel and Croce-Spinelli on a balloon flight 

that reached 28,820 feet before descending 

after all three occupants lost consciousness. 

Although Bert had warned the men about the 

necessity of using supplemental oxygen at altitude, they apparently failed to heed the advice, 

and Croce-Spinelli and Sivel asphyxiated, 

marking the first reported casualties due to 

hypoxia. Tissandier survived to tell the tale.81

During World War I, combat pilots found 

it necessary to fly above 15,000 feet to avoid 

ground fire and soon began reporting symptoms including headache, loss of muscle 

strength, dizziness, and fatigue. In addition, 

cases of unexplained losses of aircraft began to 

accumulate. Physiologists soon recognized the 

root cause as a lack of oxygen and the Army 

Air Service mounted a major effort to develop 

the “Clark-Dreyer Oxygen System,” consisting 

Ferdie Swain used a later 

Siebe Gorman suit to 

capture the world’s altitude 

record in 1936. The lineage 

of the suit to the early work 

of Haldane-Davis is obvious. 

Although the suit seemed to 

perform satisfactorily for the 

short up-and-down altitude 

flights, it severely restricted 

movement and was generally 

uncomfortable.

National Archives 

College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

42

of an automatic regulator and a leather and 

rubber mask, in 1918. However, the war 

ended before the new oxygen system was actually installed in more than a small fraction of 

Army combat aircraft.

Shortly before the end of the war, a young 

chemical engineer, Lt. Harold Pierce, joined 

the Medical Research Laboratory after completing a physiology teaching fellowship at 

Harvard University. In 1919, he designed 

a second-generation altitude chamber fabricated by the Lancaster Iron Works. The 

chamber, insulated with cork and equipped 

with a refrigeration unit, enabled researchers 

to study human response to combined cold 

stress, reduced atmospheric pressure, and oxygen starvation that occur at altitude. During 

unmanned tests, the chamber reached an altitude of 75,000 feet at a temperature of −31 oF. 

Using this facility, researchers at Hazelhurst 

built the foundation for modern protective 

flying equipment.

In November 1919, the Medical Research 

Laboratory moved to nearby Mitchel Field 

and was subsequently renamed the School of 

Aviation Medicine on November 18, 1922. 

Mitchel Field was named in honor of a former 

New York City mayor, John Purroy Mitchel, 

who was killed while training for the Air 

Service in Louisiana. Before the War ended, 

Mitchel Field served as a major training 

base for the rapidly expanding Air Service 

and proved to be an ideal home for the new 

School of Aviation Medicine. Four years later, 

in the summer of 1926, following the rapid 

postwar drawdown of the Air Service, the War 

Department moved the School of Aviation 

Medicine to Brooks Field, TX, to collocate it 

with the flight training program at that base. 

The school’s research program was redirected 

to focus on understanding the practical 

requirements for the selection and care of 

pilots. The “Mineola Chamber” was declared 

surplus and subsequently shipped to the 

Equipment Laboratory at Wright Field, OH. 

Closing the chamber was based on the school 

commander’s annual report that declared, 

“There is reason to believe that the facts of 

physiology which have been so extensively 

investigated during the past six years are far 

in advance of the immediate requirements for 

the Air Service.” This conclusion, of course, 

proved to be false.82

In the fall of 1929, Harry George Armstrong 

graduated from the School of Aviation 

Medicine and decided his future lay in military aviation. During his first assignment as 

the flight surgeon for the First Pursuit Group 

at Selfridge Field, MI, Armstrong discovered how inadequate the equipment used by 

pilots was. While flying in an open-cockpit 

Berliner-Joyce P-16 from Minneapolis to 

Chicago in late 1934, Armstrong discovered 

his flight clothing provided little protection 

against the elements. Exposed to −40 oF air 

temperatures, Armstrong suffered severe frostbite, his goggles frosted over, and he did not 

have an oxygen mask. Following his return 

to Selfridge, Armstrong thought about the 

obvious physiologic threat to combat effectiveness and wrote a letter to the Air Surgeon 

in Washington. He concluded his letter with 

a strong recommendation that the Air Corps 

Research and Development Center at Wright 

Field address the deficiencies in protective flying equipment immediately. Sometimes you 

need to be careful what you ask for. As a result 

of his letter, Armstrong was transferred to the 

Equipment Laboratory of the Engineering 

Section at Wright Field to serve as an aeromedical advisor. 

In 1935, now-Capt. Harry Armstrong established the Physiological Research Unit as part 

of the Equipment Laboratory. He discovered 

the “Mineola Chamber” sitting idle, covered 

with dust in a storage room in the basement. 

Armstrong had the chamber refurbished and 

used it for 2 years to conduct research on the 

physiologic effects of altitude. During this 

period, the Air Corps began developing the 

long-range bombardment aircraft that redefined the meaning of extreme environments. 

The Equipment Laboratory was assigned 

responsibility for development of a sealed 

pressure cabin for high-flying bombers. 

Armstrong was tasked to define the physiologic requirements for a pressurized cabin.83
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

43

To meet this challenge, Armstrong recruited 

several talented scientists, including J. William 

“Bill” Heim, who was about to complete 

postgraduate training in physiology at Harvard 

University. Heim accepted Armstrong’s 

invitation and remained at Wright Field for 

more than 31 years. Armstrong and Heim 

defined the requirements for the pressurized 

cabin demonstrated in the Lockheed XC-35 

during 1937.

Armstrong was among the first to recognize 

that in addition to the effects of altitude, 

pilots were becoming exposed to increased 

g-forces during aerial maneuvers. In response, 

he designed the first human centrifuge in the 

United States. Though unsophisticated by 

modern standards, the Balloon Hangar centrifuge, fabricated by the Equipment Laboratory 

machine shops, allowed Armstrong to study 

the effects of accelerative forces on blood pressure, first using goats, and finally humans.

Armstrong’s research encompassed virtually all 

aspects of aerospace medicine, and many of 

his investigations were the first of their kind 

to be carried out anywhere in the world. An 

abbreviated list of the aeromedical problems 

he investigated during his 6 years as director 

of the laboratory include the following:84

Hypoxia and requirements for supplemental 

oxygen; 

Reduced atmospheric pressure effects 

on the middle ear, nasal sinuses, and 

dental fillings; 

Explosive decompression;

The risk of gas bubbles forming in the 

body and prebreathing requirements; 

High-altitude flight stresses, including 

cold exposure, loss of body fluids, and 

flying fatigue;

Acceleration effects on blood pressure 

and vision; 

Vertigo, airsickness, and spatial disorientation; and 

Toxic hazards in the cockpit, including carbon monoxide and radioactive materials. 

Armstrong understood the human element 

was an important factor in aircraft design; yet 

engineers of his time paid little attention to 

the pilot. Another young physician, Dr. Otis 

O. Benson, Jr., (then a captain) became the 

second chief of the laboratory. Under his direction, the Aeromedical Research Unit separated 

from the Equipment Laboratory and formed 

three units of its own (Physiological, Biophysics, and Clinical Research). The newly named 

Aero Medical Laboratory was moved from its 

overcrowded quarters into a new building of 

its own on Wright Field, and Benson organized a research program for the laboratory 

that persisted throughout World War II. He 

staffed the laboratory with nationally known 

scientists, drawing significantly upon the 

contacts that he had developed earlier in his 

training at the Mayo Clinic and Harvard 

University. In collaboration with the Mayo 

Clinic, he established a human centrifuge 

program to evaluate G-suits and the effects of 

acceleration on pilots. Prior to World War II, 

Benson recognized the need for a radically 

different method of supplying oxygen to 

aircrews at high altitude and led the development of the diluter demand oxygen system.85

THE U.S. ARMY REDISCOVERS THE 

PRESSURE SUIT

Despite having tested Wiley Post’s full-pressure 

suit in 1934, the Army Air Corps was late to 

start the development of its own suit. It was 

not until October 10, 1939 that the Army 

tasked three companies—B.F. Goodrich, 

Goodyear Tire & Rubber, and United States 

Rubber—to investigate the concept of a fullpressure suit for crews of future high-altitude 

aircraft. Based on these initial studies, during the latter part of 1940, the Army issued 

contracts to B.F. Goodrich and U.S. Rubber 

for the development of experimental pressure 

suits. For the most part, the early pressure suit 

contracts ran concurrently with the development of the G-suit, although they seldom 

•	

•	

•	

•	

•	

•	

•	

•	
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

44

involved the same companies. Captain John 

G. Kearby of the Equipment Laboratory at 

Wright Field was the project officer for the 

pressure suit contracts.86

The requirements levied by the Army on both 

companies included completely enclosing the 

aviator, using fabric that could withstand pressure and oxidation effects, and delivering a 

prototype suit within 120 days. Other requirements, ones that would continue to prove 

difficult for decades, included permitting the 

“proper articulation of the limbs and waist” 

and using a transparent helmet “to permit the 

full visibility range.”87 At first, the Army used 

a sequential “Type” number for the pressure 

suits. Somewhat later, it adopted an “XH” 

designation (presumably for “Experimental, 

High altitude”). There was no correspondence 

between the “Type” designators and the later 

“XH” designators. 

The B.F. Goodrich contract, W535-ac-17000 

of November 29, 1940, covered the fabrication of one high-altitude pressure suit at a cost 

of $6,100. A contract amendment in February 

1941 added a second pressure suit of a slightly 

revised design. Goodrich had an advantage 

over the other contractors: its project lead, 

Russell Colley, had already developed a workable full-pressure suit for Wiley Post.88

Goodrich delivered the first Type 3 suit, called 

a “Strato-Suit” by Colley, to the Aero Medical 

Laboratory in the spring of 1941. This was a 

two-piece garment made of rubberized fabric 

that used a large transparent plexiglass helmet. 

Unlike later suits, this model was pressurized 

using oxygen and a separate oxygen mask was 

not required. The oxygen hose attached to 

the helmet ring directly in front of the face, 

perhaps not the ideal location. The tight fitting suit had metal arms and articulated metal 

elbow joints that resembled a medieval suit 

of armor. Surprisingly, according to Colley 

these elbow joints did not leak. The body 

and legs had multiple straps between various 

locations to control ballooning. During initial 

testing, the suit was pressurized to 2.5 psi 

for 10 minutes without serious leakage. The 

Army thought, however, that the neck joint 

was overly complicated and that the suit was 

difficult to don and doff.89

The U.S. Rubber contract, W535-ac-18048 

of December 19, 1940, covered the fabrication of a single pressure suit at a cost of $500 

and one G-suit for $142. The low price and 

30-day delivery schedule were the result of 

the suits having been developed by researchers at Wright Field; U.S. Rubber was simply 

fabricating them. The 80-pound Type 1 pressure suit used rubberized fabric with a lace-up 

front closure and a large transparent plexiglass 

Table 3—1943 U.S. Army Pressure Suite Designations

Original “Type” Designations Later “XH” Designations

Type 1 U.S. Rubber XH-1 B.F. Goodrich

Type 2 U.S. Rubber XH-2 U.S. Rubber

Type 3 B.F. Goodrich “Strato-Suit” XH-3 Goodyear

Type 4 U.S. Rubber XH-4 U.S. Rubber

Type 5 B.F. Goodrich “Strato-Suit” XH-5 B.F. Goodrich

Type 6 B.F. Goodrich “Strato-Suit” XH-6 B.F. Goodrich

Type 7 National Carbon Company XH-7 National Carbonic

Type 8 B.F. Goodrich XH-8 Unknown

Type 9 Goodyear XH-9 Goodyear

The designation systems were separate and reflected different pressure suits

(i.e., the Type 1 was not the same as the XH-1).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

45

helmet. Three assistants were required to 

dress the wearer. The original rubber mittens 

proved difficult to use, so U.S. Rubber manufactured a steel manipulating device, eerily 

similar to the one used a quarter century later 

by the robot on the Lost in Space television 

series, for the left arm only, as an alternative. 

Elaborate rubber accordion bellows were 

located at the elbows and knees to provide 

flexibility under pressure.90

Testing the U.S. Rubber suit at the Aero Medical Laboratory disclosed numerous deficiencies, including excessive expansion, leakage, 

and severe discomfort when the suit was pressurized. But perhaps the most critical problem, 

and the one that would prove most vexing to 

correct, was that at 3 psi the suit became so 

rigid that the wearer could barely move. The 

Army amended the contract on February 18, 

1941, to cover the addition of a single Type 1A 

pressure suit at the cost of $4,210 and a single 

Type 1G G-suit for $142, both for immediate 

delivery. Although the Army tested the two 

types of suits independently, the goal was to 

discover the best features of both and eventually to combine them into a single garment.91

As had the original Type G, the Type 1G 

G-suit proved essentially worthless, and the 

Army did not pursue the design further, 

explaining why U.S. Rubber is not mentioned 

in the G-suit chapter. When the Army tested 

the Type 1A pressure suit, an adjustment strap 

tore and U.S. Rubber switched its efforts to 

the Type 2. This revised suit was generally 

similar to the Type 1A, except it used a zipper front closure and rubber gloves. Since the 

basic suit was little changed, it too went rigid 

when pressurized. Despite a relatively poor 

showing, U.S. Rubber had substantially simplified the Type 2 suit and reduced its bulkiness and leakage.92

Shortly after the initial batch of suits arrived 

at Wright Field, the British Air Commission 

requested information concerning the 

American pressure suits. The Materiel Division 

wrote a special report for the commission 

including the latest details of the Goodrich 

and U.S. Rubber suits, and in February 1942 

provided an unidentified pressure suit to the 

Royal Aircraft Establishment at Farnborough.93

In a May 3, 1941, memo, Maj. Gen. Henry 

H. “Hap” Arnold, the acting chief of staff for 

air, informed Lt. Gen. George H. Brett, the 

Chief of the Air Corps, that the British were 

already routinely flying above 35,000 feet 

using supercharged engines in their fighters. 

Arnold believed it was essential that the 

United States be prepared to fly at these 

altitudes without using pressurized cabins, 

essentially meaning that pressure suits would 

be mandatory. To emphasize his point, Arnold 

commissioned a survey by now-Maj. Harry 

Armstrong of high-altitude operations in 

England. Armstrong discovered that, despite 

British claims, the Royal Air Force (RAF) 

had not conducted operational flights above 

35,000 feet until 2 months prior to the survey 

and did not routinely fly at such altitudes. 

Nevertheless, Armstrong endorsed the 

development of a pressure suit.94

When the Army began testing a revised 

Goodrich pressure suit at Wright Field, it 

found the new garment considerably improved 

over the initial suit. After approximately 

10 minutes with the suit pressurized to 2.5 psi, 

Army researchers noted that the overall comfort and freedom of motion were fair and 

that the normal movements required to fly 

an airplane were possible with some effort. 

The researchers also reported that the suit was 

much easier to don and doff than previous 

garments. Joint articulation, particularly of the 

fingers, was possible even at 3 psi inflation.95

These tests seemed to indicate that a 

satisfactory high-altitude pressure suit was 

attainable, and the Army awarded Goodrich 

a new contract (W535-ac-21580) on 

September 25, 1941, for two Type 5 suits. 

The first suit cost $6,500 while the second 

cost an additional $7,500. The Army wanted 

the first suit delivered within 90 days and 

the second within 180 days. These suits were 

made of rubberized fabric and used fabric 

bellows-type elbow joints braced with thin 

steel rods. There was a steel brace across the 

front of the chest that connected to shoulder 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

46

rings that supported the arms. Colley 

intended this arrangement, incorporated 

into many later Goodrich suits, to control 

ballooning. The pressurization hose, electrical 

wires, and radio connections attached to the 

left side of the abdomen. Testing showed this 

suit offered relatively decent mobility and did 

not suffer from any significant deficiencies.96

During 1941, several American aircraft 

companies expressed interest in developing 

their own pressure suits. For instance, 

Bell Aircraft submitted a $12,695 proposal 

to the Army to fabricate a single pressure 

suit, reportedly for use in a high-altitude 

version of the Bell P-39D Airacobra. During 

an inspection tour, Boeing chief test pilot 

Edmund T. “Eddie” Allen approached 

Maj. John W. Sessums, Jr., the assistant 

technical executive at Materiel Division, 

about having a Seattle company build 

a prototype pressure suit and charging 

the estimated $5,000 cost to the B-17F 

production contract. Allen indicated that 

if the suit proved successful, Boeing would 

purchase at least 10 of them to protect its 

pilots during flight tests. Sessums knew the 

problem of pressurizing the aircrew would 

eventually confront all manufacturers of 

combat airplanes equipped with turbocharged 

engines and high service ceilings. Although 

Sessums declined to allow Boeing to develop 

a pressure suit, he commented on the 

desirability of inviting engineers and pilots 

to Wright Field to coordinate the development 

of a suitable pressure suit and of familiarizing 

them with the problems involved.97

Sometime in late 1941, the aircraft companies 

decided to take things into their own hands, 

at least to some extent. Bell and Boeing joined 

with the Strato Equipment Company of 

Minneapolis, MN, to develop a pressure suit. 

John D. Akerman (1897–1972) had founded 

the company to develop oxygen equipment for 

high-altitude flight, as well as iron lungs for 

patients with respiratory paralysis. Akerman 

had an interesting biography, graduating in 

1916 from the Aeronautical School of the 

Imperial Technical Institute in Moscow, 

studying under professor Nikolai Yegorovich 

Zhukovsky, and enlisting in the Engineering 

Corps of the Russian Army’s air service 

branch. He immigrated to the United 

States in 1918 and graduated from the 

University of Michigan in 1925 with a B.S. 

in aeronautical engineering. Akerman worked 

with the Ford Stout Airplane Company 

and Hamilton Metal Plane Company and 

advanced to Chief Engineer of the Mohawk 

Aircraft Corporation. In 1929, he joined the 

University of Minnesota and founded the 

Department of Aeronautical Engineering. 

For the next 20 years, Akerman worked with 

many aircraft manufacturers and was the 

Dean of Faculty of Aeronautical Engineering 

at the University of Minnesota from 1931 

until 1959.98

Akerman was friends with Dr. Walter M. 

Boothby at the Mayo Clinic and spent a 

considerable amount of time working with 

the Mayo researchers, only 81 miles away in 

Rochester, MN. Ultimately, between late 1941 

and the middle of 1943, Akerman would lead 

the development of a series of at least nine 

pressure suits that he designated BABM for 

Boeing, Akerman, Bell, and Mayo.

Akerman designed the BABM suits to operate at 1.5 psi, meaning a pilot at 50,000 feet 

altitude would feel like he was at 37,000 feet. 

This was a much lower pressure than the 

typical 2.5–3.0 psi used by other suits. All 

of these tight fitting suits used double-layer 

construction so that a tear in one layer would 

not render the suit useless. Pilots wore the suit 

over regulation underwear and under their 

flying clothes. Six different valves were used to 

pressurize each suit, including ones that provided ventilation air for the head, hands, and 

feet. Unsurprisingly, given the Bell and Boeing 

connections, various versions of the suit were 

optimized for use in the P-39 Airacobra and 

B-17 Flying Fortress. For instance, the model 

designed for use in the B-17 had a helmet that 

could be removed from the front of the face 

rather than over the head, simplifying donning and doffing with a low overhead.99

During the week of January 12, 1942, representatives from the Army, Boeing, the Mayo 

Clinic, and the University of Minnesota held 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

47

a series of conferences in Seattle to discuss 

oxygen equipment. Boeing disclosed that it 

had contracted, using company monies, with 

Akerman to develop the pressure suit that the 

Army had declined to fund the previous year. 

Boeing acquired Akerman’s services to further its understanding of high-altitude flight 

in anticipation of improved models of the 

B-17 and the upcoming B-29. Akerman had 

already developed, fabricated, and tested several suits. However, despite progress with the 

suits, Boeing cancelled scheduled flight tests 

using a B-17E because the company did not 

believe they had sufficient understanding of 

the underlying physiology. At the time of the 

conference, the BABM suits were cumbersome 

to don and doff, it was nearly impossible to 

bend at the waist when the suits were inflated, 

and the helmets were uncomfortable to wear 

for long periods.100

In a January 12, 1942, letter, Goodyear also 

expressed interest in manufacturing highaltitude pressure suits despite their exclusion 

from the initial round of development 

contracts the previous year.101 After some 

negotiations, on July 16 the Army issued 

a $5,000 contract, W535-ac-31183, to 

Goodyear for four Type 9 suits. These twopiece garments used a unique fabric that 

promised significant advantages over previous 

fabrics. It was claimed that the fabric would 

stretch at proper joint locations, yet exhibit no 

tendency to balloon at operating pressures as 

high as 4 psi. Ward T. Van Orman, a champion 

balloon racer, headed the development effort. 

Goodyear estimated that production suits 

would cost just $200, versus $1,000 for the 

other suits under consideration.102

For 5 days beginning on January 16, 1942, 

Bell test pilot Mervin E. Erickson wore the 

third BABM suit, logically called BABM-3, 

in the newly opened Strato-Lab environmental chamber at Boeing Plant 1 in Seattle. 

Dr. Walter M. Boothby and Dr. William J. 

Randolph “Randy” Lovelace II had already 

evaluated the chamber and pronounced it 

ready for operation. The chamber had a 

108,000 British thermal unit (Btu) refrigeration unit capable of producing temperatures 

less than −100 oF.103 Erickson spent 60 minutes in the chamber at temperatures ranging 

from −57 to −61 oF accompanied by two 

Boeing technicians wearing electrically heated 

flying suits. Neither the air used to compress 

the pressure suit nor the breathing oxygen was 

heated. The suit had undergone cold weather 

testing in Minneapolis earlier in January.104

Two days later, on January 18, Erickson and 

Lovelace went to 53,800 feet in the Boeing 

Strato-Lab at temperatures as low as −4 oF. 

Boothby and Arthur H. Bulbulian from Mayo 

Clinic monitored the test. The following day, 

Al C. Reed, Boeing chief test pilot, evaluated 

the BABM-3 in a B-17 cockpit. After donning the suit, Reed spent 30 minutes moving 

around to acquaint himself with the limitations 

of the suit and then climbed into the pilot’s 

seat. Compressed air and oxygen were supplied 

through long hoses from supplies outside the 

airplane. Reed went through all the motions 

necessary to fly a mission and had major complaints about only three things: he could not 

reach the landing light switches, could not see 

the dials on one of the radios on the ceiling, 

and had great difficulty seeing instruments on 

the lower edge of the panel near his knees.105

On January 20, 1942, the Army ordered 

10 Type 6 Goodrich suits, generally similar 

to the earlier pair of Type 5 garments, for 

$34,500. A month later, the Army placed 

another order, this time for six Type 6A suits. 

All of these suits had a pressurization hose 

and electrical connection in the middle of the 

abdomen. A further modification, the Type 6B, 

incorporated a conduit that contained the oxygen hose as well as the electrical and radio connectors. The conduit attached to the left side 

of the abdomen and the wearer could disconnect it in one quick motion if he needed to 

abandon the airplane. Standard A-9 gloves and 

A-6 boots were worn over the suit for thermal 

protection. The Type 6B suit was tested at 

Eglin Field, FL, in October, and it showed 

promise, the suit still ballooned and limited 

mobility more than desired. By April 1942, 

Goodrich had progressed to the Type 8A 

suit. Although much improved, it still did 

not meet the minimum specifications.106
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

48
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

49

At the same time, the Army ordered 10 slightly 

modified U.S. Rubber Type 4A suits at a cost 

of $25,000. The 2-piece Type 4A was made 

from dark, rubberized fabric with an integral 

helmet, boots, and gloves of the same mate-

rial. The Aero Medical Laboratory deemed 

the U.S. Rubber Type 4A suits unsatisfactory, 

primarily for a lack of mobility. However, the 

lessons learned from these suits contributed to 

the development of the XH-2 suit. This twopiece ensemble used detachable rubber gloves 

and the lower legs and integral boots were 

detachable at ring joints just above the knees. 

Unfortunately, the suit was still too rigid and 

offered inadequate ventilation. This was the 

final suit produced by U.S. Rubber.107

The Army awarded Bell a contract 

(W535-ac-24203) on February 7, 1942, 

stipulating the first suit would be delivered 

within 30 days. Ultimately, developing the 

helmet would frustrate Bell, as it would most 

other developers. On February 21, 1942, Bell 

wrote the contracting officer, indicating they 

Right and photos on page 48: Researchers at the Mayo Clinic 

tested this unidentified BABM suit sometime during late 

1942 or early 1943. The suit was typical of the Akerman 

garments, being tight fitting and well tailored. Note the 

pleated knee and elbow joints and the leather straps holding 

the gloves and boots on.

All used with permission of the Mayo Historical Unit, 

Mayo Clinic, Rochester, MN

Left: During one of the tests, 

a set of cold-weather leather 

outer clothing was worn 

over the BABM pressure 

suit. Note the helmet is 

somewhat different than the 

other Akerman suits, with 

a flat metal top instead of 

being all plexiglass.

Used with permission of the 

Mayo Historical Unit, Mayo 

Clinic, Rochester, MN
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

50

The XH-2 was the last fullpressure suit produced by 

U.S. Rubber. Initially, U.S. 

Rubber had produced suits 

designed by Army researchers, 

but the XH-2 was, by all 

accounts, an indigenous 

design. Like several of its 

contemporaries, the suit had 

detachable gloves and legs 

to allow some tailoring to 

individual wearers.

National Archives 

College Park Collection

were experiencing problems developing a satisfactory method of attaching the helmet to 

the suit, and would be unable to make their 

required delivery date. Wright Field agreed to 

extend the date to April 14, 1942.108

While at a conference at the National Carbon 

Company in Cleveland on February 13, 1942, 

researchers examined a multi-layer, plasticfabric pressure suit based on the BABM 

garments designed by John Akerman. The 

suit consisted of an airtight Vinylite bladder 

worn over full-length cotton underwear 

Above: All of the U.S. Rubber suits were extremely stiff when 

pressurized. The XH-2 used pleated elbows with adjustment 

straps that afforded some mobility that had been lacking 

in early suits. Note the position of the wearer’s head in the 

helmet, graphically illustrating suit elongation. Interestingly, 

the pressure gauge on the left glove stood several inches above 

the garment. 

Courtesy of the David Clark Company, Inc.

covered by a tight fitting, single-piece restraint 

layer. A National Carbon employee modeled 

the complete 15-pound suit while inflated 

Above: The XH-2 was a two-piece design with an upper and 

lower torso that made donning the suit easy. A zipper ran 

completely around the waist and required an assistant to close 

it. Note the neck seal under the helmet and the relatively 

small hole the wearer had to maneuver his head through. 

Courtesy of the David Clark Company, Inc.

to 1.5 psi, and the garment appeared to 

be relatively flexible and offer reasonable 

mobility. Boothby and Akerman believed the 

suit was useable to 50,000 feet. Officials from 

the Aero Medical Laboratory were sufficiently 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

51

impressed to order the suit, now designated 

Type 7, to be tested at Wright Field. The suit 

ultimately proved disappointing and the Army 

discontinued development, although Akerman 

later presented a similar suit to the Navy.109

The Army held subsequent conferences at 

Goodrich and the Royal Canadian Air Force 

Institute of Aviation Medicine in Toronto. At 

Goodrich, researchers inspected the texture of 

the material the company was using for their 

pressure suits and found it was essentially 

snag-proof and almost self-sealing when penetrated by a 0.50-caliber projectile. Stating the 

obvious, the conference report commented 

that, “it was anticipated that if the suit and 

its occupant were struck by a 20mm ball, or 

larger, the occupant would have no further 

need for the pressurization.”110 In Toronto, 

researchers observed tests in the recently 

opened human centrifuge. Once more, recommendations included the construction of a 

garment that combined the features of a pressure suit and a G-suit.

After the conference, Goodrich began development of the XH-1 suit. Made of brown rubberized fabric, the suit used bellows supported 

by thin steel rods attached to rings at the 

elbows and knees. The chest brace connected 

the shoulder ring joints, and wires ran from a 

waist ring to the knees for additional support 

and to minimize ballooning. A clear plexiglass 

helmet was attached to the neck ring and, as 

B. F. Goodrich developed the XH-1 suit, part of a series of 

increasingly better suits that were ultimately judged the best 

of the Word War II efforts. Bellows at the elbows and knees 

provided improved mobility. Note the metal rod stretching 

between the shoulder rings, an attempt to control side-wise 

ballooning. This would become a feature on most of the 

subsequent suits designed by Russell Colley. 

National Archives College Park Collection

usual, the wearer wore a normal soft flying 

cover, earphones, and a demand-oxygen mask 

inside the helmet. Standard A-6 boots were 

worn over the suit’s built-in feet.111

The suit was also fit checked in a Bell P-39D Airacobra 

(41-7100). The location is not identified, but given that 

Akerman was a consultant for Bell, it is likely the Bell 

facility in Buffalo, NY. It is uncertain if an attempt was 

made to fly with the suit.

By permission of the Mayo Historical Unit, Mayo Clinic, 

Rochester, MN

On May 22, 1942, Akerman tested the 

BABM-5 suit in the Mayo altitude chamber to 

a maximum of 40,000 feet with no ill effects. 

The following day, Bell chief test pilot Robert 

M. Stanley tested the BABM-7 suit in the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

52

chamber. Stanley believed the suit was sufficiently developed to try in an airplane, and by 

June 25, Bell had modified a P-39 cockpit to 

accommodate the pressure suit. Stanley realized that the suit and airplane were not well 

matched, primarily because the cockpit was 

too small to comfortably accommodate the 

suit. Two controls at the rear of the side of the 

seat could not be reached when the suit was 

pressurized, and the landing gear switch was 

too close to the helmet to be activated with a 

gloved hand. In addition, Akerman and Stanley determined the pressurized air provided by 

the airplane contained trace amounts of oil. It 

is not clear if Stanley ever flew the P-39 while 

using the pressure suit.112

Wayne W. Nay, a senior aeronautical engineer 

at the University of Minnesota, tested the 

BABM-9 suit in the Mayo altitude chamber 

on July 19, 1942. Akerman built this suit for 

Bell according to anthropomorphic measurements provided by the Aero Medical Laboratory at Wright Field. An airtight, lightweight, 

close-fitting helmet included built-in earphones, microphone, goggles, and a demandoxygen mask. The suit had an umbilical that 

combined electrical connections, breathingoxygen, connections, and compressed-air 

connections into a single conduit. Special 

shoulder-to-hip straps provided a hinge line to 

automatically facilitate bending and to hold 

the pilot in the sitting position required by the 

P-39. The Minneapolis-Honeywell Regulator 

Company provided the valves and regulators. The suit itself weighed about 8 pounds, 

increasing to 17 pounds when including the 

helmet, boots, and accessories.113

Nay donned the suit, unassisted, in 12 minutes and doffed it in 5 minutes. During the 

altitude chamber tests, Nay could write legibly 

on a chalkboard. The suit, like many of the 

BABM models, had a unique safety feature 

built into the neck ring: pulling one clamp 

separated the ring and allowed the helmet to 

be removed quickly. Normally, the helmet was 

removed by releasing a clamp on either side 

of the neck ring. The suit required between 

3.0 and 3.3 liters of air per minute to keep it 

inflated to 1.5 psi. John Kearby tested the suit 

at Wright Field and found that it required 

80 liters per minute to maintain 1.5 psi; 

exactly what accounted for the tremendous 

difference could not be ascertained. Subsequent tests at Minneapolis-Honeywell showed 

that even with all six vent valves completely 

open, 1.45 psi could be maintained with 

only 68.7 liters per minute.114

A week later, on July 25, 1942, Al C. Reed, 

William F. Milliken, Jr., and M.J. Lunier 

took three BABM pressure suits (a BABM-8, 

-8a, and -9) to 52,100 feet for 30 minutes 

in the Mayo altitude chamber. According 

to Akerman’s account, on several occasions 

Reed, “went to the medicine cabinet, loaded 

a hypodermic needle, and pretended to give a 

hypodermic to the other two subjects.”115 This 

was meant to show the mobility afforded by 

the suit under pressure. The Mayo researchers 

monitored an Oximeter in Milliken’s ear and 

determined his oxygen level was normal during the entire experiment.

By the middle of 1942, the Army had consolidated the Goodrich, Goodyear, and U.S. Rubber efforts into classified Project MX-117.116

This was an overarching effort to provide pressure suits for high-altitude flight and G-suits 

for high-speed flight. According to a July 1, 

1942, report, various companies had delivered eight experimental pressure suits since 

October 1940, and testing at Wright Field had 

shown that five were unsatisfactory for various 

reasons. The contractors had also delivered 

10 G-suits, but no formal testing had yet 

taken place. At the time, Goodyear was under 

contract to deliver four pressure suits, and 

Goodrich and U.S. Rubber were to deliver 

10 suits each by August 1.117 Eventually, the 

Army awarded 13 contracts worth $129,695 

in support of MX-117.118

Although a good deal of research was taking place on G-suits and pressure suits, it all 

seemed uncoordinated, at least to some of the 

researchers involved. The Army attempted to 

share development information among the 

contractors and research organizations that 

were working on the suits, but this effort never 

proved completely successful. Partly this was 
53

just the state of the art at the time; the Inter-

net did not exist, and telephone and mail ser-

vice was relatively crude and slow. In addition, 

developments in rubber chemistry and fabrics 

were often jealously guarded and protected 

from competitors. Military secrecy further 

restricted or delayed access to information.

For instance, Dr. Harold Lamport from Yale 

University stated that while researchers were 

working on pressure suits at the Mayo Clinic, 

at Welfare Island, NY, and in England, it 

appeared, “there [was] a remarkable paucity 

of reports concerning any of these suits.”119 In 

retrospect, these criticisms seem exaggerated. 

The major problem was that development 

was taking place in many scattered places and 

happening very quickly, which did not allow 

researchers to engage in their normal cadence 

of preparing formal reports, attending confer-

ences, and exchanging ideas.

Partly to address these concerns, in August 

1942, the Army published the results of an 

inspection tour that had examined several of 

the pressure suits then under development. 

At Bell, inspectors reviewed the 18-pound 

BABM-9 suit developed by John Akerman. 

At Goodyear, John Kearby and Maj. Joseph 

A. Resch from the Aero Medical Laboratory donned a Type 9A suit and found the 

8-pound suit relatively flexible and comfortable at 4-psi pressure. The inspection team 

believed the suit could be adapted for gunners 

The improved Goodyear 

Type 9A suit was tight 

fitting, with a large, full 

hemisphere helmet that 

provided good visibility. The 

Aero Medical Laboratory 

found the suit relatively 

flexible at its normal 4-psi 

operating pressure, but the 

zippers leaked excessively. 

National Archives 

College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

54

and men operating in crowded positions in 

the airplane. One of its major problems was 

that, like almost all of the suits, it leaked 

around the zipper. This was solved when 

Goodyear continued to improve the Type 9 suit, resulting 

in the XH-3A, which had detachable limbs to allow sizing 

the suit to each individual. Like all of the rubber suits, the 

XH-3A exhibited too much contraction when the elbows and 

knees were bent, significantly impeding mobility and causing 

a certain amount of pain for the wearer.

National Museum of the U.S. Air Force Collection

Ward T. Van Orman, now working at Goodyear, developed an airtight zipper with overlapping, interlocked rubber strips. Van Orman 

filed a patent application on February 9, 1943, 

and the patent (2,371,776) was granted on 

March 20, 1945, assigned to the aptly named 

Wingfoot Corporation.120

Based on the results of Kearby’s evaluation, 

Goodyear built an improved XH-3 suit. This 

suit operated at 3 psi and consisted of a tightfitting single-piece garment that weighed 

12.25 pounds. A detachable transparent 

plexiglass dome helmet and integral gloves 

and boots completed the ensemble. The suit 

was donned through a crotch-to-neck airtight 

zipper. According to Kearby, it was one of 

the lightest suits and the easiest to don and 

doff. However, much like Russell Colley and 

Wiley Post—and pretty much everybody 

else—Kearby found the helmet and shoulders 

lifted upward under more than 2 psi. In addition, the suit was poorly ventilated, causing 

the wearer to perspire excessively.121

Goodyear worked on these problems, and 

the improved XH-3A had arms and legs that 

could be detached at ring joints above the 

elbows and knees. These changes facilitated 

customizing the size of the suit for each 

wearer and made donning and doffing a bit 

easier. Although much improved, the XH-3A 

still exhibited too much contraction at the 

90-degree bend of the elbows.122

At the same time, the Army subjected the 

Goodrich XH-1 to a series of altitude chamber tests that showed the suit still suffered 

from excessive bulkiness, poor mobility when 

pressurized, and inadequate ventilation. These 

faults notwithstanding, Kearby took the XH-1 

to a simulated altitude of 60,200 feet on 

October 2, 1942, and found it offered satisfactory physiological protection. This represented 

the highest altitude so far.123

During 2 weeks beginning on October 4, 

1942, a crew using four experimental pressure 

suits—XH-1, XH-2, XH-3, and XH-6—

made 5 flights in a B-17E at Eglin Field. Of 

these, the XH-1 and XH-3 appeared the most 

encouraging from a technical perspective, and 

the crew preferred the XH-3 since it was the 

lightest and easiest to don and doff. Nevertheless, the crew considered all of the suits 

too heavy and too restrictive of mobility. The 

pilots, in particular, complained the suits so 

affected their balance that movements were 

slow and awkward and that they lost the “feel” 

of their airplane. In fact, the Army ended 

the test program early, after only five of nine 

scheduled flights. The researchers concluded 

that none of the suits was truly satisfactory 

and that all needed further development.124

Seeking other opinions, on October 20, the 

Army loaned one of the Goodyear XH-3 

suits to researchers at the Naval Air Crew 

Equipment Laboratory in Philadelphia for 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

55

evaluation. Unlike Kearby, who thought the 

suit easy to doff, the Navy found it impossible 

to remove without the aid of an assistant. 

Navy evaluators also found it difficult to stand 

from a sitting position and impossible to stand 

upright under more than 2.5 psi pressure.125

Akerman demonstrated the BABM-8 suit, 

tailored for Al Reed of Boeing, at 31,110 feet 

in the Mayo altitude chamber on October 28, 

1942. For this test, Akerman used a 2-pound 

air compressor that could supply about 

55 liters of air per minute. A larger pump, 

weighing about 6 pounds, was available that 

could pressurize two suits simultaneously.126

On November 15, 1942, Akerman demonstrated the BABM-5 suit to LT Donald W. 

Gressly at the Naval Air Experimental Center at Philadelphia. Gressly was reportedly 

impressed with the suit’s mobility and many 

details of the design but felt the 1.5-psi pressure differential was insufficient. Gressly and 

Akerman discussed designing a suit that used 

a 3.5-psi differential (the same as most of the 

other pressure suits then under development), 

but apparently, no agreements were reached.127

In December 1942, researchers tested an 

improved Goodyear XH-3A suit in a B-17F at 

Eglin Field. This suit was made using a tightly 

woven cotton fabric known as “Byrd Cloth” 

and could be worn over special interwoven 

double-layer wool-cotton flying suits for 

greater warmth. Byrd Cloth was named after 

the fabric worn by ADM Richard E. Byrd and 

his team during explorations that ranged from 

the poles to the tropics. The British Army 

adopted the material in the 1940s, and it was 

considered the gold standard in military fabrics for a generation. Known to the British as 

Grenfell Cloth, the material was a lightweight, 

tightly woven herringbone twill made of longstaple Egyptian cotton. The closely woven 

fabric allowed body heat to dissipate through 

sweat evaporation. Unfortunately, Byrd Cloth 

also tended to tear at seams.128 Researchers 

made five flights to altitudes of 10,000 feet, 

10,000 feet, 32,240 feet, 39,000 feet, and 

40,000 feet and found that the fatigue caused 

by the suit’s restricted mobility limited longduration flights. The researchers believed 

that the suit exhibited too much contraction at the 90-degree bend of the elbow and 

the hose connectors on the underside of the 

neck ring were too large and heavy. In addition, the weight of the suit and its supporting 

John Kearby used a Boeing B-17E, much like this one, to 

test full-pressure suits at Eglin Field, FL. The airplane could 

not fly high enough to actually need pressure suits, but it still 

provided a realistic temperature and motion environment to 

evaluate the usefulness of the garments. 

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

56

equipment added approximately 20 pounds 

per crewmember to the airplane.129

In January 1943, Bell finally delivered its first 

BABM suit to the Army, 8 months after the 

revised delivery date. Bell indicated it had 

successfully tested the suit to 50,000 feet in 

an altitude chamber, and the volunteers that 

donned the suit had been comfortable and, 

after some practice, were able to move about 

and write legibly.130 Photographs show three of 

this model BABM suits in an altitude chamber 

at the same time, so at least that many were 

fabricated. At the Aero Medical Laboratory, 

Lt. Waring L. “Pete” Dawbarn wore the Bell 

suit for a 1-hour flight in the altitude chamber 

at 30,000 feet on March 25, 1943. Even 

inflated to only 1.5 psi, the tests revealed 

the suit suffered a severe lack of mobility 

that prevented the proper manipulation of 

simulated aircraft controls.131

Further flight tests at Eglin Field during the 

first half of February 1943 attempted to determine the usefulness of the various suits in a 

B-17 and Republic P-47 Thunderbolt. One 

extended flight in the bomber, to determine 

fatigue effects, showed that combat personnel 

could fly at any altitude without additional 

fatigue caused by the pressurized suits, contradicting earlier tests. Nevertheless, the evaluators suggested changes to the prototypes, and 

researchers wanted to make additional tests to 

better determine the pathological results that 

would accrue through frequent and regular 

use of high-altitude clothing.132

The results of the Army tests led Goodrich 

to develop the improved XH-1C, which was 

soon redesignated XH-5, as well as a largely 

new suit, the XH-6. In addition to the usual 

Goodrich chest brace, the XH-6 added a 

flexible wire that ran from the crotch up 

and across the chest and around the back. 

The arms and legs were detachable at rings 

above the elbows and knees, respectively. The 

separate arms and legs were constructed of 

heavy rubber to keep them from ballooning, 

with straps that could be fastened to help the 

wearer keep the limbs in the desired position. 

Dawbarn evaluated the suit beginning on 

April 19, 1943, and found the thick rubber 

arms and legs overly hindered mobility when 

pressurized. Work on the XH-6 was cancelled 

and all effort concentrated on the XH-5.

The Goodrich XH-5 was probably the best 

pressure suit developed during World 

War II. The suit was made of laminated 

rubberized fabric, and ball-bearing joints 

facilitated mobility at the elbows and 

knees. A Goodrich-designed self-sealing 

zipper ran from the crotch to the neck ring. 

Large, rounded bellows formed the arms 

and legs to improve mobility, leading to it 

being called the tomato-worm suit. According 

to Russell Colley, “I watched a tomato worm 

bend about 90 degrees, and the pressure in 

Although the XH-6B was developed later in the war, 

Goodrich suspended work on the suit after determining the 

earlier XH-5 provided better mobility. This photo provides 

a good view of the neck seal inside the helmet. Note the 

straps on the knees that could be fastened in a variety of 

ways to maintain the desired sitting or kneeling position. 

National Archives College Park Collection
57

the worm did not change as far as I could see. 

It did not increase in diameter; so I tried it on 

the suit.”133 Colley demonstrated the ability 

to don the 20-pound suit in under 4 minutes 

without assistance, and he stated it could be 

done in 1 minute with assistance.134 Colley 

filed a patent for this suit on August 3, 1943, 

listing Carroll P. Krupp and Donald H. Shook 

as co-inventors and B.F. Goodrich as the 

assignee. The patent (2,410,632) was awarded 

on November 5, 1946.

The XH-5 was pressurized using an 8-pound, 

24-volt electrical compressor that supplied 

5 cubic feet (141 liters) per minute (cfm) 

at 3 psi and operated up to altitudes of 

80,000 feet. The same type of combined 

umbilical first used on the Type 6B was fitted 

at the left side of the abdomen. The wearer 

wore a standard A-14 demand oxygen mask, 

although Goodrich also developed a smaller 

mask that could be worn instead.

The Army ordered a single XH-5 on April 10, 

1943, at a cost of $3,350, but at least five oth-

ers were delivered (one photo shows six suits 

in the Wright Field altitude chamber). Reports 

indicate more than 30 subjects wore the suits 

in the altitude chamber during tests as high 

as 80,000 feet. In September, Armstrong took 

the suits to Eglin Field and made five flights 

aboard a B-17F at altitudes up to 25,000 feet. 

The evaluators determined that despite its 

advances, the XH-5 was still uncomfortable, 

The Goodrich XH-5 was 

commonly called the tomatoworm suit, in reference 

to its exaggerated bellows 

on the arms and legs. The 

laminated rubber fabric 

suit was somewhat bulky 

and sagged when it was not 

pressurized. This was in 

stark contrast to the tightfitting Mark IV suit that 

Russell Colley would later 

design for the U.S. Navy. 

National Archives 

College Park Collection
58

Bell delivered this version of the BABM suit to the Army 

in January 1943, and the suit was extensively tested by 

Boeing. The tight-fitting suit provided adequate mobility 

when unpressurized, but proved extremely stiff when 

pressurized even to 1.5 psi. The suit still required the use 

of a traditional oxygen mask inside the large clear helmet.

The Boeing Company
59

It is uncertain how many BABM suits were produced, 

but this photo shows three of the suits being worn in front 

of the Strato-Lab environmental chamber at Boeing 

Plant 1 Seattle. Despite being aesthetically appealing, the 

tight-fitting suits proved disappointing since they were 

very stiff while pressurized. John D. Akerman was the 

primary designer of the suits, and between late 1941 and 

the middle of 1943 he led the development of a series 

of at least nine pressure suits designated “BABM” for 

Boeing, Akerman, Bell, and Mayo.

The Boeing Company
60

As with all of the contemporary suits, it was impossible 

to stand straight while the 

XH-5 was pressurized. This 

was not considered particularly significant but served 

to demonstrate the relative 

lack of mobility afforded by 

the suits. Perhaps the most 

significant advantage of the 

XH-5 was that it did not 

elongate excessively, and the 

pilot’s head stayed centered 

within the hemispheric 

plexiglass helmet. 

National Archives 

College Park Collection

suffered from inadequate ventilation, and 

required too much effort to move the arms 

and legs when pressurized. Wearers were 

unable to use the Norden bombsight, the 

defensive machine guns, or the radio controls 

on a B-17. Although it might be possible to 

adapt the airplane to the suit, as built, the suit 

could not adapt to the airplane. 

The Army ordered the final Goodyear suit, 

the $750 XH-3B, on April 7, 1943, and 

the suit was tested late in the year. For the 

most part, this suit was an evolutionary 

development of the garments that had come 

before. Van Orman filed for a patent on this 

suit on October 6, 1943, and it (2,401,990) 

was granted on June 11, 1946. Ultimately, 

along with the Goodrich XH-5, this suit 

came closest to meeting the stated Army 

requirements for a full-pressure suit.135

During the summer of 1943, the U.S. Navy 

tested several of the Army pressure suits at the 

Naval Air Crew Equipment Laboratory in Phil-

adelphia. LCDR Donald W. Gressly was the 

flight surgeon in charge, assisted by mechani-

cal engineer L.W. Meakin. For the most part, 

the Navy did not identify the suits by a model 

number, only by a manufacturer, making it 

difficult to determine exactly what they tested. 

However, their observations were interesting.

Between February 15 and February 19, 1943, 

Meakin and physicist W.E. Scott tested a 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

61

This photo shows at least four XH-5 suits in the Wright Field 

altitude chamber (only a part of the fourth suit may be seen 

at center right in a crouched position). Other photos from 

this series show six suits. The two suits nearest the camera are 

not fully pressurized, allowing the wearers to stand straighter 

than normal (note the hunched position of the suit at the 

back of the chamber). 

National Archives College Park Collection

25-pound U.S. Rubber suit under the supervision of then-Lieutenant Gressly. The suit consisted of an upper and lower torso section, and 

separate arms and legs attached via metal rings 

on the upper arms and thighs. Two zippers 

connected the upper and lower torso with an 

inflatable rubber tube between them as a seal. 

A metal neck ring formed a twist-type lock 

joint with the dome helmet. A Wiggins Type 

108A demand regulator supplied oxygen.136

At 1.5-psi inflation, arm and leg movement 

proved possible but difficult, and it was only 

possible to stand up from a sitting position 

with great difficulty. The elongation of the 

suit made downward vision nearly impossible. 

At 2.5 psi, the suit was even more uncomfortable and less mobile. At this pressure, the 

helmet had risen to the point that outward 

vision was nearly non-existent and it was 

impossible to stand up even with assistance. 

At both 1.5 and 2.5 psi, the left elbow 

joint opened unexpectedly. At 3.5 psi, all 

movement was impossible. Gressly wore 

the U.S. Rubber suit in the Navy altitude 

chamber up to 60,000 feet without incident, 

although perspiration proved to be a problem 

and movement was largely impossible.137

Between June 1 and July 15, 1943, the Navy 

tested the 22.25-pound B.F. Goodrich Type 

5E Strato-Suit that operated at 3.5 psi. Metal 

shoulder joints with ball bearings allowed 

360-degree rotation, and metal arm and leg 

connector rings allowed various size limbs to 

be attached as needed. Accordion pleats in 

the hip, knees, and elbows were designed to 

facilitate mobility. The pilot donned the suit 

through a zipper, covered by rubber flaps, 

which ran from the crotch to the neck. The 

Goodrich garment used a Wiggins Model A15 

diluter demand type oxygen regulator with the 

diluter side closed off. The suit used a neck seal 

and a dome helmet connected via a grooved 

metal ring with a clamp. There was a differential pressure gauge on the left forearm.138

During sea-level tests of the Goodrich suit, 

Greesly and Meakin found the garment 

leaked around the neck ring and the ring 

bent easily, making it impossible to secure 

the helmet until it was repaired. The suit, 

designed for a 6-foot man, did not fit either 

of the Navy evaluators particularly well, 

making it difficult to judge its comfort. 

When pressurized to 3.5 psi, the shoulders 

and helmet rose such that the neck ring 

almost covered the eyes. Standing up from 

a sitting position was accomplished only 

with great effort, but arm, finger, leg, and 

foot motions were “comparatively good.” 

The suit could be self-donned, but mobility, 

even when unpressurized, was insufficient 

to enter a fighter cockpit without assistance. 

When the suit was pressurized, the pilot 

could not see many of the instruments, could 

not operate any of the controls on the side 

consoles, and could not reach up to open or 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

62

The B.F. Goodrich Type 5E Strato-Suit weighed 22.5 pounds 

and was significant in having detachable arms and legs, 

allowing a certain amount of tailoring for the individual. 

The neck seal for the helmet is shown at top left. 

Courtesy of the David Clark Company, Inc.

close the canopy. The suit was not adequately 

ventilated, and perspiration accumulated in 

the gloves and boots. In addition, the location 

of the oxygen inlets, near the ears, resulted 

in an unacceptable noise level. Greesly and 

Meakin found the suit unacceptable in 

its current form but believed it could be 

improved relatively easily.139

Concurrently with their tests of the Goodrich 

suit, between July 5 and July 16, 1943, 

Gressly and Meakin tested a 20-pound suit 

made by the Strato Equipment Company. 

The BABM suit the Navy tested was representative of the later John Akerman creations. 

The suit was made of two layers of rubberized 

fabric, operated at 1.5 psi, and consisted of 

five pieces: an upper torso, trousers, a pair of 

gloves, and a helmet. Metal connecting rings 

at the neck, waist, and wrists secured the 

pieces together. There were leather straps running from the waist ring over the shoulders to 

prevent rising and from the waist to the crotch 

to prevent elongation. A pocket under each 

armpit creased by thin wire aided mobility 

for the arms. Straps across the stomach and 

thighs provide breaking points in the inflated 

fabric for forward bending and sitting. Three 

clamps attached the gloves to a rubber gasket, 

and a standard Army harness and parachute 

was worn over the suit. There were five zippers 

on each suit: one 11-inch zipper on each side, 

one 11-inch zipper on the trouser at the waistline, one 11-inch zipper on the chest of the 

torso, and one 11-inch zipper on the back of 

the torso. In theory, flaps on the inner side of 

each zipper provided an airtight seal.140

The double-layer transparent methylmethacrylate helmet was 11 inches in 

diameter with an elliptical top. The front 

of the helmet sloped down below the 

neckline to provide downward visibility, and 

a perforated tube ran around the front side 

of the top to distribute air and prevent 

fogging. The helmet was attached to the suit 

using two clamps on a neck ring. Like all of 

Akerman’s suits, a third clamp provided a 

way to quickly separate the neck ring and 

helmet with one motion in case of an 

emergency. Dry air was trapped between the 

layers of the helmet to prevent fogging.141

Ventilation air was routed through spring 

tubing to the middle of the back, head, arms, 

hands, and legs. The head ventilation port 

was automatically closed when the helmet was 

removed. The ventilation valve automatically 

closed when the air supply was disconnected 

to ensure the suit remained pressurized for a 

short time. This was intended for use when 

the pilot bailed out of an airplane. The 

Type B-12 constant-flow oxygen mask had 

two inputs—one from the airplane and one 

from the bailout bottle—and automatically 

switched to whichever one was delivering 

pressure. Akerman used a Wiggins Type 15A 

diluter demand-oxygen regulator.142

Sea-level testing revealed minimal leakage, but 

the suit was difficult to don and doff without 

assistance. Downward visibility was good, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

63

and elongation and helmet rise were well 

controlled. The wearer could easily climb into 

the cockpit of a Vultee SNV-1 trainer (the 

Navy version of the BT-13A Valiant) without 

assistance when the suit was deflated. With 

the suit inflated to 1.5 psi, gross movements 

were easily accomplished, but fine movements, 

such as adjusting instruments or controls in 

the cockpit, were very difficult. The ventilation in the suit was adequate and no excessive 

perspiration was noted. Perhaps the largest 

complaint was a pungent odor, likely from 

the particular plastic, within the helmet that 

caused extreme nausea. Gressly tested the 

suit in the altitude chamber to a simulated 

50,000 feet. He noted that any movement 

within the suit, or pressing on the outside 

of the suit, caused a partial deflation, and 

because of this, internal pressure varied 

between 0.7 and 1.5 psi constantly.143

Between July 12 and July 21, 1943, Gressly 

and Makin tested a Goodyear suit that operated at 2.5 psi. The black rubberized fabric 

one-piece suit weighed 12.25 pounds and 

used a Wiggins Type 108A demand regulator. 

Donning the suit was done through a front 

zipper with rubber flaps that ran from the 

crotch to the neck ring. A hinge-type clamp 

attached to the rubber neck ring tightened 

the ring around the dome helmet to form 

The Type 5E was not 

particularly flexible, and 

this hunched-over stance 

was about as straight as 

a subject could stand. 

Although evaluators 

considered limb motion 

“comparatively good,” 

a seated pilot could not 

operate many cockpit 

controls when the suit 

was pressurized. 

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

64

The BABM-18, created by John Akerman’s Strato Equipment 

Company, was one of the most advanced of the World War II 

suits. The suit was fabricated in five pieces: the upper torso, 

trousers that included pressure footings, a pair of gloves, and 

the clear helmet. The oddly shaped helmet was a recurring 

theme on several BABM and early David Clark Company 

full-pressure suits. 

Courtesy of the David Clark Company, Inc.

an airtight seal. A pressure gage was on the 

left forearm, and built-in restraint straps prevented elongation of the suit.144

Tests of the Goodyear suit showed that it was 

impossible to stand up from a sitting position without assistance, and even then it was 

impossible to stand upright when the suit was 

inflated. Oddly, Gressly thought the “rubber flap and zipper seal was satisfactory” even 

though the suit lost 1 psi per minute when 

the air supply was shut off. Since the suit was 

made in a single piece, a tear in a glove or leg 

would render the entire suit useless until it 

was repaired, unlike the multi-piece suits from 

Goodrich and others in which a new arm or 

leg could be attached easily. The cockpit evaluation showed the wearer had a very restricted 

range of vision and could not see any control 

or instruments in the airplane. Shoulder, arm, 
65

hand, and leg mobility was difficult and 

tiring, and there was no ventilation in the 

arms or legs, leading to excessive perspiration. 

The Navy evaluators also commented that 

the suit had no provisions for adjusting to 

subjects of varying heights and weights, 

meaning that a custom suit would need to 

be made for every pilot, something the Navy 

believed unacceptable.145

Between November 3 and December 9, 1943, 

Gressly and Meakin tested a 34-pound General 

Electric pressure suit. The suit consisted of a 

one-piece rubberized fabric inner suit, outer 

trousers, an outer waist section, a methylmethacrylate dome helmet, gloves, and metal 

crotch reinforcement. The suit used a neck seal 

and there were small vents in the toes and back 

of the gloves to help ventilation. The suit fea-

tured hinged metal shoulder rings to improve 

mobility and restraining straps across the arms, 

upper thighs, and from the knees to the instep 

to prevent elongation. The metal crotch sup-

port prevented ballooning and facilitated hip 

and trunk motion.146

The Navy found the suit was difficult to don 

and doff without the aid of an assistant. The 

rubber neck seal was fragile and tore easily, 

and despite the toe and hand vents, subjects 

perspired excessively. When the suit was not 

inflated, subjects “were able to move about 

quite freely,” but when it was inflated to 

2.5 psi, all motions were made with great 

The BABM-18 used leather 

straps that ran from the waist 

and crotch over the shoulders 

to control elongation, 

although the design of the 

helmet still allowed the pilot 

to see even if it rose several 

inches. Note the break points 

at the knees and waist to 

allow bending.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

66

This Goodyear suit was much 

less sophisticated than the 

contemporary XH-3A for 

not having detachable limbs. 

Like most suits of the era, 

the suit elongated excessively 

as it pressurized—note the 

position of the subject’s head 

within the suit while in 

the seated position. This, of 

course, made it nearly impossible to pilot an airplane 

while wearing the suit. 

Courtesy of the David Clark 

Company, Inc.

difficulty.147 The suit was worn by a representative of General Electric in the Navy altitude 

chamber up to 50,000 feet altitude. At 2.5 psi 

in the chamber, fine motions were jerky and 

difficult and the subject perspired excessively.

The Navy concluded its evaluation of the 

Army suits with a note that, “all suits so far 

tested have been characterized by requiring so 

much exertion to enable the person within to 

maintain a normal sitting position that generalized fatigue is outstanding.”148 The report 

noted that movement was practically impossible at 3.5 psi in any of the suits. The Navy 

also seemed to place a different emphasis on 

what movements were important. 

Manufacturers’ claims of fine movements 

in the fingers and hands do not clearly 

represent the basic problem of mobility 

for it is in the area of greatest diameter, 

such as the trunk, thighs, and shoulder 

rotation where mobility has been found 

to be greatly restricted by pressure. Also, 

rotation of the forearm from the elbow 

joint has been exceedingly difficult. All 

movements from these areas of greater 

diameter are of a rough, jerky type and 

are often of lesser or greater magnitude 

than intended. In the standing or kneeling positions, as may be required of 

bombardiers or gunners, the restriction 

in motions necessary for these men to 

be efficient are considered too great due 

either to the inability to perform the 

motions or the fatigue resulting from 

such performance.149

The Navy also criticized the suits as too heavy, 

uncomfortable, and not sufficiently ventilated 

to remove perspiration. Seemingly ignoring 

the state of the art in airtight fabrics, the Navy 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

67

Top Left: The General Electric suit had a one-piece gas 

container with built-in booties and glove liners. Separate 

outer gloves were provided. The metal shoulder rings were 

supposed to allow increased mobility while pressurized, 

but testing at the Naval Air Crew Equipment Laboratory 

showed that motion was jerky and difficult, even at a 

relatively low 2.5 psi. 

Top Right: General Electric used a two-piece outer suit to 

further control ballooning and provide a protective layer 

for the delicate rubber gas container. The outer suit used 

integral boots and had a variety of straps to provide some 

size tailoring and control ballooning. 

U.S. Navy photos, courtesy of the David Clark Company

Like most of the full-pressure 

suits of the era, this General 

Electric suit ballooned when 

it was pressurized and 

significantly restricted mobility. 

Note the unusual stance of 

the wearer. GE included a 

variety of straps on the arms 

and around the torso in a 

generally unsuccessful attempt 

to control ballooning.

U.S. Navy photos. Courtesy 

of the David Clark Company
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

68

researchers believed any pressure suit should 

be made of a lightweight fabric, although they 

noted that the General Electric and Akerman 

suits, which used such fabric, tore too easily 

under pressure. Acknowledging a problem first 

noted by Russell Colley and Wiley Post, the 

Navy researchers found all the suits elongated 

to the point that the helmet rose above eye 

level. The Navy concluded that “none of the 

pressure suits ... have been able to fulfill the 

requirements” needed for an operational suit. 

Much like the Army, the Navy concluded the 

Goodrich suit, although unsatisfactory, offered 

the most promise.150

The Army program suffered a major setback 

on August 2, 1943, when Maj. John G. Kearby 

(1905–1943) was killed after his Lockheed 

A-28 Hudson crashed. He was returning to 

Wright Field after flight-testing a full-pressure 

suit at Eglin Field. In addition to being 

project manager, Kearby had been the first 

subject to test an Army pressure suit in an 

altitude chamber and the first to test one 

in flight. On October 18, 1943, Maj. Gen. 

Franklin O. Carroll, chief of the Engineering 

Division, recommended Kearby be 

posthumously awarded the Legion of Merit; 

Maj. Gen. Charles E. Branshaw, commander 

of the Air Materiel Command, concurred on 

January 10, 1944. The citation noted that, 

“Between November 1942 and March 1943, 

Maj. Kearby personally conducted extensive 

flight tests of the pressure suit at Eglin Field, 

running risks which not only endangered 

his life, but which were far beyond the call 

of duty.”151

Despite the setback, the Army tested the 

improved Goodrich XH-5 and Goodyear 

XH-3B suits at Eglin Field in September 

1943 and found them airworthy but not 

ready for combat. The Goodyear suit, in 

particular, severely restricted mobility to the 

point that it was unsuited for use at any crew 

position, but it provided sufficient physiological protection to be used on special missions 

to any altitude readily foreseen as possible. 

Nevertheless, the improved suits showed 

remarkable advancements over the original 

pressure suits tested in 1942.152

Researchers concluded that none of the suits 

tested over the past year were sufficiently 

advanced to warrant quantity production. At a 

conference at Wright Field, the Materiel Division stated it was time to either buy the suits 

as they were or close the project since development had gone as far as possible at that time. 

The consensus was that Goodrich was at least 

a year ahead of all the other companies on 

pressure-suit development. After its evaluation 

of several Army pressure suits, the Navy stated 

that, although generally interested, it had no 

need for high-altitude suits. Many researchers 

also felt that the entire concept of a pressure 

suit competed with the concept of a pressurized cabin. Interestingly, the Army had not 

given company representatives the freedom 

to work with its suits in actual airplanes or 

to take its suits to aircraft manufacturers for 

evaluation, excepting Bell and Boeing, which 

had developed their own suits. Representatives at the conference concluded that the 

Army should discontinue the pressure suit 

development effort but that one suit should be 

retained to determine fatigue and metabolism 

characteristics and for characterizing movements physiologically.153

On October 12, 1943, Randy Lovelace, chief 

of the Aero Medical Laboratory, advised 

each of the contractors that the Army had 

decided to terminate MX-117. On October 

29, the Army officially discontinued pressure 

suit development and surplused the research 

equipment that had supported the effort.154

A USAF Technical Report released in March 

1949 stated that, “basically, all attempts to 

develop equipment around the principle of 

full pressurization for survival at altitudes had 

failed because of the inability to resolve the 

fundamental paradox of adequate mobility at 

high pressure.”155 The report further stated 

that, “it would be extremely unwise and most 

unfair to state categorically that the fully 

inflated suit might never be used at high pressures for long periods of time (4-6 hours).”156

The relative failure of the Army full-pressure 

suit development effort did not deter movies 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 2: Mark Ridge, Wiley Post, and John Kearby

69

and magazines from featuring the suits. For 

instance, the July 2, 1945, issue of Time 

Magazine contained an article entitled, “Science: A Shape that Came,” along with a photo 

of a “spacesuit” used in the 1933 movie The 

Shape of Things to Come and a photo of a B.F. 

Goodrich Strato-Suit prototype tested by the 

Army in 1943. The article said:

One of the costumes that the cinemadapters of H. G. Wells’s The Shape of Things 

to Come dreamed up is here. The flyer 

is wearing a “Strato-Suit” developed by 

the late Major John G. Kearby of the Air 

Technical Service Command and by B. F. 

Goodrich Co. Designed for high-altitude 

flying, the electrically heated, pressurized 

suit could theoretically keep a man comfortable at 80,000 feet. The plastic bubble 

enclosing the head has oxygen for breathing, a microphone and earphones for 

communication. A man can zip himself 

into the suit in two minutes.157

Similarly, the November 1945 issue of Popular 

Science contained an article describing the B.F. 

Goodrich suit.

Made of rubberized fabric, a new flexible, pressurized “Strato-Suit” for flyers 

may enable flyers to go farther than ever 

before into the stratosphere. Developed 

by the AAF Air Technical Service Command and B.F. Goodrich Company, the 

suit has proved practical in pressurechamber tests equivalent to 80,000 feet, 

or 15 miles above the earth. When fully 

pressurized, the suit surrounds the airman 

with four pounds of air pressure. It provides oxygen for breathing, microphone 

and earphones for communication, and 

electricity for heated underwear. All are 

‘piped in’ via a single junction assembly 

that can be disconnected in one quick 

movement. A transparent plastic bubble 

headpiece is removed in less than a second by a secret device. Donned in two 

minutes, the suit has airtight and watertight zipper enclosures.158

If only it were so.

SUMMARY

Although several of the pressure suits developed during the 1930s appeared to work and 

were even used on a limited number of “operational” flights, none were truly satisfactory. 

All of them were heavy and had extremely 

limited mobility. In addition, there was a 

surprising lack of scientific method applied to 

their development, most being almost “hobby 

shop” efforts rather than true engineering 

projects. The Army efforts of the early 1940s 

were better organized and funded but failed 

to live up to the initial expectations. Despite 

some limited successes, the waxing winds of 

war turned most efforts to more immediate 

needs, such as improved oxygen systems, parachutes, and clothing to keep aviators warm. 

As legendary test pilot A. Scott Crossfield later 

opined, “During World War II, the armed 

services, absorbed with more vital matters, 

advanced the pressure suit not a whit.”159
3
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

71

3: Acceleration Protection

Despite the failure of the U.S. military to 

develop a workable full-pressure suit during World War II, a separate effort yielded a 

perhaps more important garment. Pressure 

suits and “anti-gravity” suits, more often called 

G-suits within the industry, serve two separate, 

but ultimately related, purposes, and their 

development was intertwined. Although not a 

specific topic of this book, G-suits are discussed 

since many of the concepts, institutions, and 

people involved with their development are 

inseparable from pressure-suit developments.

In the same year, 1903, that the Wright 

brothers made their first powered flight at 

Kitty Hawk, an American doctor published 

Blood-Pressure in Surgery, a book that had 

more to do with aviation than was understood 

at the time. George W. Crile, a cofounder of 

the Cleveland Clinic, reported that bandaging 

the extremities of experimental animals raised 

their blood pressure and that compression of 

the abdomen raised it further.1

 Crile believed 

a suit constructed using similar principles 

might be useful to maintain the blood pressure of patients on the operating table. To 

control the externally applied pressure more 

precisely during human experiments, Crile 

developed a rubber suit that he could inflate 

using a bicycle hand pump. However, despite 

some limited successes during surgery and 

postsurgical recovery, Crile eventually concluded that the suit was “cumbersome and 

uncomfortable.” As alternate treatments 

became available, Crile’s suit was forgotten.2

Blood pressure, what Crile was attempting to 

control with his suit, plays an important role 

in any human activity and is one of the key 

parameters to maintaining consciousness. It 

has long been known that quick or extreme 

movement can cause a person to temporarily 

lose consciousness, or to “black out.” This is 

true of any physical activity, but is perhaps 

most closely associated with pilots flying 

highly maneuverable aircraft capable of high 

g-forces. Ultimately, this phenomenon was 

linked to blood pressure, and its eventual mitigation is credited to a variant of Crile’s suit.

Interestingly, the first blackout resulting from 

centrifugal force occurred only a week after 

the Wright brothers flew at Kitty Hawk. 

The roots of the event went back to the late 

19th century when Sir Hiram Stevens Maxim 

(1840–1916), an inventor with a machine 

gun and the common mousetrap to his credit, 

wanted to build an airplane. By 1894, he 

had largely given up. However, as part of his 

research, Maxim built a test rig that used twopassenger cars hung using cables from a large 

spinning frame; as the machine spun, the cars 

swung outward, simulating flight. Experiments 

using the machine continued long after Maxim 

abandoned his attempts to build an actual airplane. During one of these tests, in December 

1903, Dr. Albert P. Thurston,3 an engineer 

working for Maxim, took a ride and promptly 

lost consciousness as the car exceeded +6-Gz of 

centrifugal force.4 Fortunately, Thurston woke 

up a little dazed but none the worse for the 

experience. Despite the incident, Maxim saw a 

commercial opportunity and further developed 

the rig into the “Sir Hiram Maxim’s Captive 

Flying Machines”5 amusement park ride, which 

was installed for the 1904 exhibition at Earls 

Court in London.6 He subsequently built additional rides at the Crystal Palace and various 

English seaside resorts including Southport, 

New Brighton, and Blackpool. The Blackpool 

ride, at least, is still operating.7

Despite this early introduction to the potential problem, the issue of what is now called 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

72

gravity-induced loss of consciousness 

(G-LOC) was not widely recognized for over 

a decade. An article published in 1919 by 

Dr. Henry Head (1861–1940), an English 

neurologist knighted for his pioneering medical research, observed a phenomenon he called 

“fainting in the air” in pilots of highly maneuverable airplanes such as the Sopwith Camel. 

By 1920, experiments had shown that these 

blackouts lasted about 20 seconds and began 

as the vertical acceleration exceeded approximately +4.5-Gz. The pursuit airplanes (what 

are now called fighters) of World War I were 

certainly capable of rendering their pilots 

unconscious, but popular legend indicates 

that the pilots who could train themselves 

to withstand the maneuvers did not want to 

talk about it because it made them appear 

less professional, and those who could not 

adequately adapt were dead.8

After the war, air racers frequently talked 

about fuzzy vision or loss of concentration 

while making sharp turns around marker 

pylons. By the time the Coupe d’Aviation 

Maritime Jacques Schneider (commonly called 

the Schneider Trophy) for the highest speed 

by a seaplane was permanently secured by 

Great Britain in 1931, loss of visual acuity, or 

blacking out, had become a serious problem 

in closed-circuit air racing. The Supermarine 

S.6B used during the last Schneider Trophy 

race could easily sustain 6-G in turns around 

the course markers, but the physiological 

implications were not thoroughly understood 

at the time.9

THE PHYSIOLOGY OF ACCELERATION

Acceleration is measured in multiples of the 

normal acceleration due to Earth’s gravity, 

which is 32.2 feet per second per second 

(ft/sec/sec). The normal force (+1-Gz) applied 

from head to foot upon a standing person 

with a mass of 175 pounds is 175 pounds. 

However, if this same person is subjected 

to an acceleration of +7-Gz, the force then 

applied from head to foot is 1,225 pounds, 

creating obvious problems for the body and 

Three axes represent the human body when discussing the 

forces of acceleration. The X-axis (transverse) runs front to 

back through the chest, the Y-axis (lateral) is side to side 

through the shoulders, and the Z-axis is vertical from head to 

feet. A body can be impacted either positively or negatively in 

each axis. Aerodynamics dictate that almost all accelerations 

felt by a seated pilot are in the Gz axis. 

Dennis R. Jenkins
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

73

internal organs. At +7-Gz, blood is as heavy 

as iron, and the heart is not capable of pumping enough blood against the acceleration to 

maintain adequate circulation.10

As with any coordinate system, three axes represent the human body. The X-axis (transverse) 

runs front to back through the chest, the Y-axis 

(lateral) is side to side through the shoulders, 

and the Z-axis is vertical from head to feet. A 

body can be impacted either positively or negatively in each axis. The physiological effects 

of G-loads vary with the magnitude and duration of the acceleration, what axis of the body 

the acceleration acts against, and where on the 

body it is applied.11

Aerodynamics dictate that almost all accelerations act upon the seated aviator from head to 

foot—in other words, Gz. Positive Gz pushes 

the body into the seat and drains the blood 

from the head toward the lower extremities. It 

becomes difficult to breathe as the ribs and the 

internal organs are pulled down, emptying air 

from the lungs. The heart has to pump harder 

to get blood to the brain, partly because the 

blood weighs more; eventually it is unable to 

do so. The magnitude of the acceleration is 

a function of the velocity of the aircraft and 

the radius of the circle circumscribed. By the 

beginning of the 1930s, some aircraft, such 

as the Supermarine S.6B, were capable of sustained +6-Gz maneuvers; by the 1970s, this 

had increased to +9-Gz. The human body, no 

matter how fit and well-trained, is incapable 

of functioning in this environment.12

To increase human tolerance to acceleration, 

it is necessary to maintain blood pressure to 

the brain. Unfortunately, the elasticity of the 

human vascular system allows blood to pool in 

the lower extremities under acceleration.13 Low 

arterial pressure first impacts the eyes, beginning around 3-G, when the loss of peripheral 

vision causes a tunnel vision effect.14 Slowly, 

cone vision will start to disappear until vision 

is completely lost but the individual is usually 

still conscious.15 If the acceleration continues, 

unconsciousness follows. Consciousness is 

regained as acceleration decreases, although 

this normally results in the dazed or confused 

feeling experienced by Albert Thurston. This 

phenomenon is what Henry Head called 

“fainting in the air.” 

Conversely, in a negative Gz condition, much 

like when standing on one’s head, blood is 

forced away from the lower extremities and 

toward the head. The first symptom of –Gz 

is a sense of facial and, especially, eye fullness 

and congestion followed by occasional visual 

“red out.” 

Human tolerances to positive transverse acceleration (+Gx) are much higher than +Gz conditions, commonly reaching about +15-Gx. 

The key problem with transverse acceleration 

rests in the increased difficulties of inflating 

the lungs. Negative transverse acceleration 

(–Gx) results in breathing difficulties above 

–10-Gx.16 Lateral (Gy) acceleration is not a 

significant concern regarding consciousness, or 

breathing, but it does have a significant effect 

on supporting muscles, such as the neck.17

Applying science to what pilots had been 

doing since World War I, researchers— 

principally, at the Mayo Clinic—developed 

a series of anti-G straining maneuvers during the early part of World War II to help 

pilots maintain consciousness. These involve 

specialized, sequenced isometric muscle 

contractions and timed breathing routines 

that allow pilots to manually press with their 

muscles and lungs to squeeze the heart, forcing blood to the head. The general procedure 

is to contract the lower extremity, buttocks, 

and abdominal muscles while taking a deep 

breath and holding it. At the same time, the 

pilot began straining immediately prior to the 

onset of acceleration. This was followed by a 

strict cycle of rapid inhaling, straining while 

gradually exhaling through the partially open 

glotti. This sequence was repeated at 3-second 

intervals. These maneuvers require practice 

to achieve proficiency, and they are difficult 

to perform and fatiguing at the best of times, 

let alone in combat. A well-executed anti-G 

straining maneuver provides up to +3-Gz of 

protection and is a very important aspect of 

acceleration protection. Many pilots have 

mastered the anti-G straining maneuvers, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

74

often with life-saving results. Just how well an 

individual pilot is able to handle high accelerations comes down to just how proficient they 

are in the issues of their domain.18

Although everybody agreed the anti-straining 

maneuvers helped, they were physically tiresome and diverted a pilot’s attention away 

from flying his aircraft and tracking the 

enemy. Researchers continued to look for tools 

that would assist the pilot with G-protection 

and decrease the need for extended straining. 

The development of the G-suit was a major 

advance during World War II. As with most 

new technologies, its gestation was confusing and complicated, although the pressures 

of war kept it short. What follows is not a 

definitive history of G-suits but rather an 

introduction to many of the individuals and 

institutions that were also ultimately involved 

in the development of the aviation pressure 

suits discussed later.

HUMAN CENTRIFUGES

Before delving into G-suits, it is appropriate 

to examine one of the main tools researchers 

used to test human tolerance to acceleration: 

the centrifuge. Erasmus Darwin (1731–1802), 

physician, physiologist, abolitionist, inventor, 

and poet, and grandfather of Charles, 

explored the nature of sleep in his 1818 book, 

Zoönomia.

19 Darwin believed the centrifugal 

force resulting from rotating a body in 

circles might be useful to reduce heart 

activity, suppress fever, and induce sleep. To 

further this belief, James Watt (1736–1819), 

the Scottish inventor and mechanical 

engineer whose improvements to the steam 

engine were fundamental to the Industrial 

Revolution, designed a hand-powered 

“rotative couch” for Darwin. Although it is 

unlikely the device was ever built, Darwin 

and Watt were probably the first to envision 

a human centrifuge.20

By 1877, Austrian physicist and philosopher 

Ernst Mach (1838–1916), best remembered 

for his study of shock waves and compression 

theory, formulated a hypothesis that gravity 

and centrifugal force were equivalent in their 

action on the sensory organs. Albert Einstein 

(1879–1955), the 1921 Nobel Laureate in 

physics, later came to the same general 

conclusion—that the effects produced by 

gravity and inertial forces are indistinguishable. Charles-Auguste Salathé was probably 

the first physiologist to recognize their 

equivalence for the cardiovascular system.21

Although largely unrecognized at the time, 

it was an important realization.

Although human centrifuges were constructed 

by several nations during the late 1800s for 

medical reasons, this account will focus on 

the acceleration work starting in the 1930s 

in Australia and North America as being particularly pertinent to this story.

Militaries recognized the potential importance of research into acceleration protection, 

and the U.S. Army Air Corps opened the 

first human centrifuge in North America on 

May 6, 1935, inside the abandoned Balloon 

Hangar at Wright Field. A 20-foot arm allowed 

the device to produce up to 20-G, and the subject could sit or lie on an adjustable platform 

at the end of the arm. By 1937, Dr. Harry G. 

Armstrong (1899–1983) and Dr. J. William 

Heim (1903–1988) used the Balloon Hangar 

centrifuge to acquire sufficient data to 

publish their now-classic paper “The Effects 

of Acceleration on the Living Organism.”22

Armstrong played a major role in aerospace 

medicine in the United States. After attending the University of Minnesota for a year, he 

joined the U.S. Marine Corps before returning to school. Armstrong received his M.D. 

from the University of Louisville in 1925 and 

entered the Flight Surgeon Training Program 

at the Army School of Aviation Medicine at 

Brooks Field, TX. In 1931, Armstrong received 

an appointment as flight surgeon to the First 

Pursuit Group at Selfridge Field, MI.23

In a 1934 letter to the Federal Air Surgeon in 

Washington, DC, Armstrong urged giving a 

higher priority to improving protective flying 

equipment. As a result, the Army assigned 

him to the Engineering Division at Wright 

Field. After a while, Armstrong suggested the 

need for a separate medical research laboratory 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

75

to deal with the physiological aspects of 

flying. In May 1935, the Air Corps established the Physiological Research Unit with 

Armstrong as its director. Its initial mission 

was to discover ways to provide aircrew protection from temperature extremes and the 

lack of oxygen at high altitude.24 In 1939, 

Armstrong published Principles and Practices 

of Aviation Medicine, considered the standard 

text for over two decades.25

In 1946, the Army named Armstrong Commandant of the School of Aviation Medicine at 

Randolph Field, and in June 1949, he became 

USAF Deputy Surgeon General. The following 

December, he was named USAF Surgeon General. Armstrong retired from the Air Force in 

1957 as a major general and died in 1983.26

Back in 1935, while organizing the new Physiological Research Unit, Armstrong sought the 

advice of Dr. Cecil K. Drinker and his brother 

Philip Drinker, at the Harvard School of Public 

Health. Cecil’s research included blood circulation and methods of artificial respiration. Philip 

was an industrial hygienist who, among other 

things, invented the first widely used iron lung 

in cooperation with Louis Agassiz Shaw. Several years earlier, Harvard had built an altitude 

chamber to research pressure related physiology, 

primarily as it pertained to deep-sea divers. On 

the advice of the Drinker brothers, Armstrong 

ordered a duplicate of their altitude chamber 

and hired their physiologist, J. William Heim, 

to operate it.27 Armstrong and Heim, would go 

on to design the Balloon Hangar centrifuge.

Over the course of the next 6 years, Armstrong 

developed, among many other things, crash 

helmets and shoulder-type safety belts. A 

number of the experiments and investigations 

Armstrong performed were the first of their 

kind, and he regularly participated as a test 

subject. Critical to the story of pressure suits, 

he discovered what is now known as the 

Armstrong Line. At approximately 63,000 feet, 

the vapor pressure of water (47 mm Hg) is the 

same as the atmospheric pressure (47 mm Hg), 

and water boils at the normal temperature of 

the human body. It is important to note that 

this applies to unconfined water, such as saliva 

and tears. Normal human diastolic blood 

pressure is sufficiently high that, contrary to 

oft-repeated myth, a living person’s blood will 

not boil in a vacuum, although there are many 

other physiological issues that will quickly kill 

an unprotected human.28

Meanwhile, on the other side of the planet, in 

mid-1941, the University of Sydney installed 

a centrifuge in the laboratory of professor 

Frank S. Cotton (1890–1955) funded by 

the Royal Australian Air Force (RAAF) and 

the Australian National Health and Medical 

Research Council. Charles W. Prescott designed 

the machine, and White Elevators, Ltd. of 

Sydney built it. Two 10-hp electric motors 

drove the turntable to a maximum acceleration 

of 9.5-G at a radius of 9 feet. Unlike other 

centrifuges with swinging cabs that were built 

during this period, this one moved the subject 

and measuring instruments outward and 

inward along the radius of rotation. Sets of 

guide rails ran from the center of the turntable 

to the outer rim. The chair carrying the subject 

traveled on one set of rails and on the other set 

were the counterweights necessary to maintain 

dynamic balance. The weights traveled 

inward as the chair travelled outward with the 

movement occurring as the turntable reached 

the required angular velocity.29

The Australians were 

early adopters of human 

centrifuges. This machine 

was designed by Charles W. 

Prescott and installed in the 

laboratory of Professor Frank 

S. Cotton at the University 

of Sydney. The device was 

capable of generating 9.5-G. 

Photos courtesy of John 

Dodson, University of Sydney 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

76

The Royal Canadian Air Force (RCAF) commissioned the first modern human centrifuge 

in North America (having been predated by 

the original Wright Field Balloon Hangar 

device) under the leadership of Nobel laureate 

Sir Frederick Grant Banting (1891–1941), 

the codiscoverer of insulin and Chair of the 

Banting and Best Institute for Medical 

Research at the University of Toronto.30 In 

this case, the centrifuge came in response to 

a specific need. One of Banting’s colleagues, 

Dr. Wilbur R. “Bill” Franks (1901–1986) 

was developing a water-filled G-suit and had 

used a Fleet 16 Finch biplane trainer to test 

the original prototype. It was obvious to 

Banting and Franks that a safer and more 

controlled means of testing was necessary. Not 

only were flight tests potentially dangerous and 

subject to the whims of unpredictable weather, 

but they also did not provide the precisely 

controlled environment that Franks required 

to understand and improve his creation.31

During 1939, Franks and George A. Meek 

completed the preliminary design for a 

high-speed human centrifuge. In 1940, 

the National Research Council approved 

C$25,000 funding, and Victory Aircraft 

built the machine (called an “accelerator”) 

with assistance from various departments 

at the university. At the time of its opening in late summer 1941, the RCAF device 

was the fastest and most powerful human 

centrifuge in the world and was the first that 

could realistically mimic the effects of aircraft 

acceleration on the human body.32 By August 

1945, the Canadians had carried out more 

than 13,000 human runs without a mishap.33

A pit 12 feet deep and 31.5 feet in diameter 

housed the device, which, had a single 8.5-foot 

horizontal arm attached to a central shaft. A 

200-hp electric motor rotated the central shaft, 

causing the spherical gondola to swing out on 

moveable joints to an almost horizontal position. The seat was suspended independently 

of the gondola, allowing the subject to be 

positioned at different angles inside the gondola, including in an upside-down position to 

produce negative-G—an unusual feature. The 

centrifuge was capable of accelerating to 20-G 

in 3 seconds.34

An observer outside the centrifuge would 

turn on lights and sound a buzzer; the 

subject responded by turning the signals 

off. A failure to turn off the lights indicated 

the subject could not see; however, he was 

likely still conscious and could respond to 

the buzzer. A failure to turn off the buzzer 

indicated the subject was unconscious. 

Researchers monitored the subjects using 

electrocardiographs, electroencephalographs, 

and a photoelectric device attached to the 

earlobe that measured blood flow to the head. 

The latter instrument confirmed that high 

accelerative forces greatly reduced the volume 

of blood going to the head.35

The United States also built several additional 

human centrifuges. The first came in 1942 

at the Mayo Clinic under the direction of 

Dr. Edward J. “E.J.” Baldes (1898–1975) and 

Dr. Charles F. Code. The pair recognized that 

researchers would need a repeatable method 

of replicating flight conditions to uncover the 

physiological underpinnings of the blackout 

problem. The Mayo Clinic machine was not as 

powerful as the Canadian device, but was more 

capable than most other human centrifuges of 

the era and designed to specifically allow for 

optimal biomedical data recording without 

the necessity of a huge central motor. It was a 

collaborative design between the Mayo Clinic 

biophysics staff (especially Adrien Porter) 

and the Sperry Gyroscope. The device had a 

20-foot arm, could generate 2-G in 5 seconds, 

and add 2-G per second until it reached 10-G. 

The centrifuge stored rotational energy in two 

20-ton flywheels purchased from a Cincinnati 

brewery, powered by an engine from a “reasonably priced” wrecked Chrysler automobile. 

The engine drove the flywheels via a normal 

automotive tire and wheel, although this presented an initial problem as tires were rationed 

during the war, and Mayo could not explain 

why it needed one without compromising the 

security of the project. Fortunately, David M. 

Clark, who will play a major role in this story, 

had contacts within the rationing system and 

procured a brand-new tire for the centrifuge. 

Once the flywheels reached about 40 revolutions per minute (rpm), the operator popped 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

77

a clutch to clamp the resting gondola (with 

the subject inside) onto the spinning wheels. 

“You’d take off with a tremendous zip,” Baldes 

noted, “and the g would be applied almost 

instantaneously.”36 The Mayo centrifuge was 

instrumental in the development of the American G-suit.37

The second modern American centrifuge 

opened in 1943 at Wright Field, replacing 

the earlier Balloon Hangar device that had 

been in use since 1935. This machine, located 

in the Centrifuge Building (Bldg. 55), had 

a 48-foot double boom with a cab on each 

end. The device could accelerate to 22-G in 

9 seconds. Capt. George L. Maison, chief of 

the Acceleration Unit, was the first to ride the 

device. Between its opening in May 1943 and 

the beginning of 1946, 280 persons made several thousand runs on the machine under the 

supervision of Lt. Col. F. Gregory Hall, chief 

of the Physiology Branch.38

In late 1943, a group from the University 

of Southern California (USC) School of 

Medicine arrived at the Mayo Clinic to 

study the human centrifuge in preparation 

for building a similar device in Los Angeles. 

Included in the group were Dr. Douglas R. 

Drury, Dr. William G. Clark, and Dr. James 

P. Henry from the Departments of Physiology 

and Aviation Medicine.39 This group, and the 

centrifuge they ultimately built, would play 

a major role in the development of pressure 

suits. The 23-foot centrifuge, funded by the 

National Research Council, opened in 1944 

and could produce a peak acceleration of 

20-G with an onset of 6-G per second. 

Human centrifuges, it seems, were the 

special province of James Henry, who later 

replaced Maison as chief of the aptly named 

Acceleration Unit at the Aero Medical 

Laboratory. To his credit, Henry rode just 

about all of the devices in his domain, 

although this may not have been much 

consolation to those who followed. Next to 

John Paul Stapp, Armstrong probably endured 

more physical agony in the name of science 

than any other man of his generation.

Within the U.S. Navy, research in aviation 

medicine took place at the Medical 

Department of Naval Air Station Pensacola 

from 1939 until 1946. To support this 

research, Pensacola opened a 20-foot human 

centrifuge in 1945 that could operate at 20-G 

with a 2-G-per-second-rate of acceleration. 

On October 1, 1946, the Secretary of the 

Navy established the Naval School of Aviation 

Medicine at Pensacola that included the 

human centrifuge.40

By the end of the 1940s, these centrifuges 

allowed researchers to study the effects of 

increased gravitational levels, as represented 

by centrifugal force, on the pressure and 

The human centrifuge at the 

Mayo Clinic was essential 

in evaluating the original 

American G-suits, particularly those developed by the 

David Clark Company. The 

gondola at the end of the 

arm was a simple tube box 

with a seat (for sitting experiments) or table (for prone). 

The gondola was at the end 

of a 20-foot arm and could 

generate 10-G. 

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

70

“The Wheel” at the Naval Air Development Center 

(NADC) in Johnsville, PA, was by far the most 

sophisticated of the postwar human centrifuges. 

This device could attain 40-G and was used to 

train pilots for the X-15 and astronauts for Dyna-Soar, 

Mercury, and Apollo. The gondola sat at the end of a 

50-foot arm and a control room was located above 

the centrifuge. 

U.S. Navy
71

The original single-person gondola at Johnsville was hardly 

the high-tech environment of today. The pilot sat on a 

simulated ejection seat and initially faced an instrument 

panel that was little more than an oscillograph with a 

few extra lights. Many early tests involved the pilot moving 

the control stick to follow a trace on the screen. During the 

X-15 program, researchers installed a full X-15 instrument 

panel, complete with side-stick controllers in the gondola. 

NASA followed with a simulated Mercury capsule instrument panel and controls. Pilots did not think the simulation 

provided by the human centrifuge was particularly realistic, 

but it offered at least a hint of the extreme accelerations 

provided by the X-15 and early manned launch vehicles. 

U.S. Navy

distribution of blood in the lungs, heart, 

brain, and legs. Using these devices, the 

nature of human tolerance to acceleration was 

well established, the cardiovascular factors 

limiting human tolerance to short-term accelerations were identified, and a general theory 

of the function and operation of the vascular 

system at 1-G had been firmly established. 

Many researchers believed they had solved the 

major aeromedical problems in this area.41

Despite the increasing sophistication of the 

wartime centrifuges, one device would ultimately render all of them obsolete. In 1950, 

the U.S. Navy dedicated what was then, by 

far, the world’s most sophisticated centrifuge, 

although it seemed something of a white 

elephant at the time. Much later, in 1962, the 

chief of the NASA astronaut corps, Donald 

K. “Deke” Slayton, opined, “We feel that 

the centrifuge [Johnsville] has been one of 

our most valuable training devices.”42 The 

centrifuge was the centerpiece of the Aviation 

Medical Acceleration Laboratory, located at 

the Naval Air Development Center (NADC) 

in Johnsville, PA. The designers of what pilots 

often called, with a mixture of pride and fear, 

“the Wheel” anticipated the rapid growth in 

aircraft performance and foresaw the need for 

a new research tool. The resulting centrifuge 

had a 10-G-per-second-rate of acceleration 

and could attain 40-G, whereas previous centrifuges were limited to 6-G per second and a 

maximum of 22-G. Johnsville had a 50-foot 

radius as compared with other centrifuges that 

had radii between 10 and 23 feet. An altitude 

chamber 10 feet in diameter and 6 feet wide 

on the arm provided the ability to test at any 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

80

altitude, including a vacuum, at temperatures 

from well below zero to nearly 200 oF. A pair 

of gimbals allowed the altitude chamber to 

assume virtually any attitude. The inner 

gimbal provided 360 degrees of rotation at 

rates up to 30 rpm, while the outer gimbal 

rotated outward through a 90-degree arc. 

Although the Navy had originally intended 

the Johnsville centrifuge for research, it 

became a primary training tool for the X-15, 

Dyna-Soar, and Mercury programs.In 1963, 

the Navy replaced the gondola with a larger 

unit to accommodate the three-person-wide 

configuration needed to train for Apollo. 

Today, the Wheel is a deserted building in an 

industrial park where the NADC used to be.43

THE BEGINNING OF AN IDEA

It appears that the National Advisory 

Committee for Aeronautics (NACA) had 

the distinction of employing the first person 

hospitalized for “overexposure” to acceleration. 

According to a June 8, 1928, letter from flight 

surgeon Capt. Ira F. Peak, Jr., to Richard V. 

Rhode, an aeronautical engineer at the Langley 

Memorial Aeronautical Laboratory, an Army 

Air Corps Reserve test pilot on duty with the 

NACA lost consciousness on a flight in September 1927. Peak wrote:

On examination he showed generalized conjunctivitis of both eyes. He also 

showed generalized systemic neurological 

symptoms leading me to think he had a 

mild cerebral concussion with some generalized cerebral capillary hemorrhage or at 

least a marked degree of passive traumatic 

enlargement. Being interested in the case, 

I wrote complete descriptions to Doctor 

Schneider of Western University, and to 

Dr. Louis H. Bauer, Medical Director 

of the Air Regulations Division at the 

Department of Commerce. Both of them 

agreed with my opinion of the cause and 

nature of this condition, namely, it was 

due to sudden changes of centrifugal force 

while doing high-speed flying in acceleration tests. There was a duty recovery from 

this condition in about two weeks and 

complete recovery in about a month. 44

Based on data from the doctors, Rhode 

concluded airplanes were reaching the limits 

of human tolerance to violent maneuvers, 

and that since the “pilot is the limiting factor 

... there is no need to curtail performance 

by over-strengthening the airplane structure 

or by reducing control.”45 In other words, do 

not build airplanes capable of greater acceleration than an unprotected pilot could endure. 

Rhode, an otherwise brilliant engineer who 

later became assistant director for advanced 

design for NASA, apparently never considered 

providing any sort of protection for the pilot.

Despite the relatively insignificant budgets 

that hampered the U.S. military during the 

interwar years, the U.S. Navy and U.S. Army 

Air Corps began looking seriously into the 

blackout problem. During the early 1920s, 

a pilot practicing for an air race remarked to 

LT John R. “Jack” Poppen, a nonflying naval 

flight surgeon, that his vision began to dim as 

he rounded the pylons at speed but returned to 

normal on the straight portions of the circuit. 

The Navy began to investigate the phenomena 

in 1921, using an accelerometer mounted on 

a Curtiss JH-4 Jenny to measure aircraft load 

factors. This was, probably, the beginning of 

scientific research into acceleration effects on 

pilots in the United States.46

By 1927, Poppen was in charge of the 

Aviation Section at the Naval Medical 

School in Washington, DC, and was making 

great strides toward introducing aviation 

medicine as a formal discipline. Poppen 

was a consultant to the NACA committee 

that established a method of investigating 

aircraft accidents and was instrumental in 

changing the way the gyroscopic artificial 

horizon worked. When Sperry Gyroscope first 

introduced the artificial horizon instrument, 

the horizon line remained stationary while the 

symbol of the airplane moved. When many 

pilots, including Jimmy Doolittle, experienced 

difficulty remembering that the moving bar 

represented the horizon and not the airplane, 

Poppen realized there was a problem. After 

a few years of argument, Poppen published 

an article in 1936 that seemed to settle the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

81

matter. Essentially, Poppen’s rationale was that 

the instrument should be an exact analogue 

of what the pilot was seeing through the 

windscreen, a standard still in use.47

The Navy soon awarded a small grant to the 

Harvard School of Public Health to study 

acceleration effects. While conducting experiments on animals exposed to high g-forces, 

Poppen and Dr. Cecil K. Drinker found that 

abdominal restraint diminished blood pressure 

effects when acceleration occurred along the 

vertical axis of the body. During 1932, Poppen designed a pneumatic abdominal belt that 

a pilot could inflate with a hand bulb prior 

to an anticipated exposure to acceleration.48

Harry Armstrong and John Heim tested the 

belt on the 20-foot centrifuge at Wright Field 

in 1936 and found it of “some benefit.”49

In 1939, the Navy flight-tested another version 

of the Poppen belt, a device later shown in the 

1941 movie Dive Bomber starring Errol Flynn 

and Fred MacMurray.50 Pilots reported limited, 

but not adequate, protection, and there was the 

larger problem of needing to anticipate when 

to inflate the belt, a luxury of time that combat 

seldom allowed.51 Although the abdominal 

belt had been Poppen’s own idea, an indirect 

link to George Crile had introduced Poppen 

to the concept of a G-suit. In 1941, Crile was 

in an aircraft that flew through the remnants 

of a tornado, and the resulting turbulence 

caused the flightcrew to lose consciousness; 

This illustration was used by 

Berger Brothers to describe 

the sequence of events that 

often led to a pilot blacking 

out during a dive-bombing 

mission. As aircraft became 

faster and more maneuverable, the problem became 

more widespread and was 

not restricted to the vertical 

maneuvers shown here. 

Berger Brothers. 

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

82

In 1932, LT John R. “Jack” Poppen, a naval flight surgeon, 

developed what became known as the Poppen Belt to fight 

the effects of acceleration. The concept was valid, but the belt 

needed to be inflated using a hand bulb (shown) in advance 

of being needed (a technique not well suited to the flight environment). A later version of the device was featured in the 

1941 movie Dive Bomber. 

Courtesy of the David Clark Company, Inc.

the airplane crashed but Crile survived. In his 

autobiography, Crile wrote:

After the experience of everyone in the 

plane, it seems clear to me that the cause 

of the blackout in aviation must be the 

failure of the blood to return to the brain 

and the heart because of the rapid ascent 

of the plane. 

So many times I have seen an unconscious patient restored to consciousness 

by being placed in the head-down position that the blackout seems to me to 

be just one more phase of the problem 

that I have been trying to solve for so 

long and which I solved years ago theoretically if not practically by the device 

of the pneumatic suit which provided 

artificial peripheral resistance, giving 

control over the blood pressure within a 

range from 25 to 60 mm mercury. This 

suit enveloped the body up to the chest. 

Were an aviator encased in this suit and 

the pneumatic pressure established, the 

suit in itself would prevent pooling of the 

blood in the large vessels in the abdomen 

and extremities and would maintain the 

conscious state. 

I believe that an aviator thus equipped 

would be protected against the failure of 

the blood to return to the heart and hence 

would have protection against blackout.52

Crile understood the principle of a G-suit 

and took his idea to Dr. Eugene F. DuBois, 

the chairman of the Committee on Aviation 

Medicine, one of the branches of the Advisory 

Committees to the Surgeons General of the 

War and Navy Departments and the Public 

Health Service.53 Crile had already discussed 

his pneumatic suit with DuBois and now suggested the idea could be used by dive bomber 

pilots to prevent blackout during the high-G 

pullout at the bottom of their attacks. DuBois 

agreed the suit might hold promise to protect 

pilots during violent maneuvers and suggested 

Crile contact Poppen.54

Separately, in November 1940, Dr. John F. 

Fulton, an American physiologist at the Yale 

University Medical School, suggested that 

pressurized leggings might keep blood from 

accumulating in the lower limbs during acceleration. This was not a new idea, having been 

put forward in a German-language book by 

Dr. Siegfried Ruff and Dr. Hubertus Strughold 

the previous year.55 Fulton constructed a set of 

inflatable leggings that worked with the inflatable abdominal belt to force blood upward 

from the lower extremities. Fulton did not 

have access to a human centrifuge for testing, but Dr. William K. Stewart of the RAF 

Institute of Aviation Medicine flight-tested 

the leggings at the Royal Aircraft Establishment (RAE) in Farnborough, England.56

Stewart, a respected British pioneer in aviation 

medicine, had been investigating the effects 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

83

of acceleration and found that about half of 

those who experienced blackout had amnesia 

and could not remember the event. As the 

head of a 1940 British research effort, Stewart 

made a flight expressly to experience blackout. 

Afterward he was disappointed that nothing 

had happened—until he saw photographs of 

himself unconscious.57

Stewart decided to test Fulton’s leggings. One 

of the leggings ruptured during the first flight, 

and it was evident that the covering fabric was 

inadequate. The RAE fabricated a new set of 

leggings that underwent limited, albeit inconclusive, testing. In addition, the three-piece 

assembly (individual leggings and the abdominal belt) was awkward to don.58

Although the leggings proved disappointing, 

they provided an unexpected inspiration for an 

American who happened to be at Farnborough 

during the tests. Frederick D. Moller would 

subsequently play a significant role in the 

development of a workable G-suit.59

AUSTRALIAN COTTON 

AERODYNAMIC ANTI-G SUIT

Ultimately, American researchers would make 

the most progress toward a workable G-suit, 

but the Australians and Canadians also recognized the potential benefits of the device and 

conducted extensive research that predated 

most American efforts.

Australian physiologist Frank S. Cotton 

(1890–1955) was a professor at the University 

of Sydney specializing in the study of the 

effects of physical strain on the human body. 

In 1940, Cotton showed that the cardiac 

output, which decreases considerably when 

a change is made from the supine (lying 

on back) to the standing posture, is nearly 

fully restored when the standing body is 

surrounded by water up to the lower part 

of the sternum.60

The war in Europe was in full swing, and 

the Battle of Britain took place between July 

and October 1940. This was the first major 

skirmish fought entirely by air forces, and 

the RAF Fighter Command gained a welldeserved reputation during the fight. Ten 

thousand miles from London, Cotton followed the battle in the local newspaper. One 

article in particular caught his attention: pilots 

were suffering from acceleration effects during 

the dogfights taking place daily over England. 

Cotton was certain he could find a solution to 

help the pilots avoid the “dreaded blackout.”61

Cotton already knew a considerable amount 

about cardiac output. He also knew that 

German research several years earlier had 

shown that the hearts of great apes were 

nearly empty of blood after centrifuge tests; 

it is difficult to pump blood to the head when 

there is no blood in the heart. This led Cotton 

to believe that applying pressure to the lower 

extremities and abdomen would keep blood 

available to the heart. The obvious answer was 

to make a suit containing a set of bladders 

that automatically inflated to some as-yetundetermined pressure. Cotton made the first 

suit by cutting up two women’s bathing costumes (long before the invention of the bikini 

rendered salvaging fabric pointless) and gluing 

them to a pair of rubber boots. A rubber hose 

connected the ensemble to an air compressor 

and pressure valve.

During November 1941, Cotton began testing the suit and found the concept worked as 

he had predicted. On the advice of the RAAF, 

Cotton took the prototype suit to Britain, 

Canada, and the United States on a demonstration tour beginning November 21, 1941. 

Unknown to Cotton, by this time the waterfilled Franks Flying Suit was already in limited 

production in Canada. Regardless, Cotton 

met with Bill Franks and exchanged ideas. In 

the United States, Cotton met with Poppen, 

who was impressed with the gradient-pressure 

feature of the suit and passed the idea along 

to Moller at Berger Brothers for use in their 

air-filled suit.

After he returned to Sydney, Cotton 

carried out further trials using the Australian 

centrifuge. The test subjects were Flight Lt. 

Robert H. Thompson and Flight Lt. Ken V. 

Robertson; both men were of similar size 

and build and could use the same suits. In 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

84

The Royal Austrian 

Air Force conducted operational trials using Curtiss 

Kitty-hawks. Unfortunately, Australia’s Northern 

Territory capital of 

Darwin experiences hot 

weather most of the year, 

and pilots complained 

the suit was unbearably 

hot while sitting alerts in 

their un-air-conditioned 

cockpits and readyrooms. 

National Archives 

College Park Collection

March 1942, Thompson began testing the suit 

using the only Hawker Hurricane (V7476) in 

Australia, followed by Robertson in April. On 

one flight, the Hurricane pulled over 10-G, 

causing minor damage to the airplane without 

ill effect to the pilot. Preliminary data was sufficiently encouraging that the RAAF ordered 

the suit into production. Operational trials 

began on October 20, 1942, using Curtiss 

P-40E Kitty-hawks at the No. 2 Operational 

Training Unit at Mildura, Victoria. Six pilots 

were involved in the tests, including five with 

extensive combat experience. Flight-tests 

results generally agreed with the results from 

the Sydney centrifuge, where a maximum of 

9-G had been obtained. Despite its benefits, 

pilots reported the suit was hot and uncomfortable, not ideal traits for Australia during 

the summer.

At a conference between the RAF and 

RAAF on May 15, 1943, the British urged 

the Australians to continue in which the 

Australians were developing the gas-filled 

Cotton suit, the British and Canadians had 

already fielded the water-filled Franks suit, 

and the Americans were working on air-filled 

suits from Berger Brothers and the David 

Clark Company.

The Cotton suit became operational with 

No. 452 Squadron at Strauss Airfield near 

Darwin, Australia, in July 1943. This, however, amplified a major problem with the 

suit. The squadron was responsible for the 

defense of northern Australia, meaning that 

pilots spent long hours on alert, sitting in the 

cockpit or a nearby readyroom, prepared to 

takeoff on short notice. Unfortunately, the 

temperatures in Darwin during July are well 

above 80 oF, with 80-to-100-percent humidity. Air-conditioning was largely unheard of at 

the time, and the crews found sitting around 

in a rubber suit unbearable. Relief came 

from an unexpected source: Mac Robertson 

Steam Confectionery Works provided an airconditioned chocolate van for the pilots to 

use as a readyroom. This same company had 

sponsored the 1935 air race that had inspired 

Wiley Post to develop the first pressure suit.

The pilots from No. 452 Squadron were generally impressed with the Cotton suit, excepting the complaints about heat. They did note 

that frequently the suit did not deflate after 

returning to normal 1-G flight, and this 

made it difficult to fly the airplane smoothly 

since the feeling of the controls, particularly 

the rudder pedals, was different. There was 

another, potentially more serious issue with 

the parachute straps between the thighs not 

spreading correctly when seated. Robertson 

expressed the concern eloquently in his report, 

quipping that “I am not yet convinced that 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

85

one’s matrimonial value will not drop to zero 

if one bails out wearing a suit.”62 He suggested 

fitting guide loops that would hold the thigh 

straps apart when seated, or adopting the 

American-style parachute harness that always 

stayed separated because of its different design 

and sewing.

In August 1943, the RAAF conducted trials 

that pitted a Spitfire Mk V against a Mitsubishi A6M Zero at Eagle Farm, Brisbane, 

Australia. The Australians assembled the Zero 

from parts found on Papua, New Guinea, by 

the Allied Technical Air Intelligence Unit. 

The tests showed the Zero was more maneuverable than the Spitfire at all altitudes when 

neither pilot was wearing a G-suit, but the 

Spitfire could gain the upper hand if its pilot 

was wearing a suit and the Zero’s pilot was 

not. Based on the results of these trials, the 

RAAF decided to equip the Spitfires of No. 1 

Fighter Wing with the Cotton suit. However, 

the Australians apparently never used the 

Cotton suit in combat.63

The production model of the Cotton Aerodynamic Anti-G Suit (C.A.A.G.) Mk I was 

manufactured by Dunlop Rubber Co. Ltd. 

(Australia) and was commonly called the “Zoot 

Suit” by operational pilots.64 The 25-pound 

suit consisted of a series of overlapping rubber bladders inside a set of rubber latex fabric 

high-waist short trousers and leggings. Initially, 

the leggings extended from the soles of the 

feet, but later models started at the ankles. 

The short trousers overlapped the top of the 

leggings, extending about halfway down the 

thigh. This allowed adjustment to compensate 

for different body builds. The shorts contained 

a lower bladder that covered the abdomen 

and extended into the legs of the shorts and 

an upper bladder that extended to the lower 

edge of the ribs. Each legging contained four 

bladders for the thigh, upper leg, lower leg, 

and boot. A full-length zipper extended along 

the front of each legging. A short hose connected the suit to a cylinder of compressed 

carbon dioxide, and an acceleration-sensitive 

valve released gas into the suit in proportion 

to the acceleration it sensed. The suit applied a 

gradient of 16 different pressures to the body 

from the ankles to the abdomen.65

By late 1944, the Australians had developed 

the so-called “Kelly One-Piece” (K.O.P.) suit 

in an attempt to produce a protective garment that was lighter and more comfortable 

than the original C.A.A.G. suits. The Mk I 

version of the K.O.P. provided five levels of 

The Royal Australian Air Force equipped its Supermarine 

Spitfire Mk Vs, such as this RAF example, with the Cotton 

G-suit but apparently never used the suit in combat. 

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

86

gradient pressure from the feet to the waist, 

while the slightly lighter Mk. II version used 

only three pressures. Although the suits were 

an improvement, they still lagged behind the 

Berger Brothers and David Clark suits being 

manufactured in the United States and were 

soon forgotten.66

CANADIAN FRANKS FLYING SUIT

The Royal Canadian Air Force developed 

the first modern human centrifuge in North 

America under the leadership of Nobel 

laureate Sir Frederick Grant Banting (1891–

1941), the codiscoverer of insulin and chair 

of the University of Toronto’s Banting and 

Best Institute for Medical Research.67

Peter Allen, who wrote a paper on the early 

years of Canadian aviation medicine for the 

Canadian Aviation Historical Society Journal, 

gives much of the credit for getting Sir 

Frederick involved to Maj. A.A. James of the 

Royal Canadian Army Medical Corps. James 

had spent a year studying the state of aviation 

medicine in other countries. “Realizing that 

all countries except Germany were appallingly 

unprepared to support their aircrews in the 

coming war, James was determined to see 

that situation changed in Canada.”68

The Department of National Defence formed 

the Associate Committee on Aviation Medical 

Research in June 1939.69 Soon thereafter, 

using a grant from the Canadian government, 

Banting purchased the Eglinton Hunt Club 

near downtown Toronto for use as an aviation 

medicine research facility. This was initially 

known as the No. 1 Clinical Investigation 

Unit and later as the RCAF Institute of 

Aviation Medicine.70 In 1940, the institute 

built a low-temperature altitude chamber.71

One of Banting’s colleagues, Dr. Wilbur R. 

“Bill” Franks, was conducting cancer research, 

and it was not immediately apparent what he 

could contribute to aviation medicine—until 

he heard James explaining that fighter pilots 

were losing consciousness during high-speed 

maneuvers.72 The military considered this one 

of the most pressing problems affecting the 

performance of their pilots, and James told 

researchers it would provide an enormous 

tactical advantage if the G-tolerance of Allied 

pilots could be increased.73

Earlier in his career, Franks had solved a 

problem with glass test tubes breaking in his 

laboratory centrifuge by floating them in 

water while they were spinning. Wondering 

if the same principle applied to pilots, Franks 

experimented with mice in his small centrifuge and found they could withstand extreme 

accelerations (up to 240-G) when “immersed 

in water up to their necks inside condoms.” 

Specifically, he observed, “that mice, when 

suspended in a fluid the specific gravity of 

which approached that of the mouse’s body, 

could withstand, without apparent damage, 

over 100 times the normal gravity.”74

It was obviously not practical to suspend pilots 

in fluid-filled cockpits, so Franks decided to 

develop a fluid-filled suit a pilot could wear. 

Although the concept was straightforward, 

Franks was uncertain exactly how to construct 

the garment. He approached the Dunlop 

Rubber Company, Ltd. and Dominion 

Textiles, Ltd. to develop a suitably strong 

and nonextensible fabric. The problem then 

became the joints, which eventually had to use 

vulcanized fabric.75

Oddly, the Canadian government declined to 

provide funding for the experiment, but fortunately, Harry McLean, an eccentric Toronto 

businessman known for his philanthropy, 

donated $5,000 (Canadian dollars), which that 

allowed Franks to buy the materials and hire a 

tailor to make the first suit using an old sewing machine in his office.76 This suit covered 

the entire body from neck to toes and used 

a nonextensible outer covering to withstand 

stretching and direct the fluid inward against 

its wearer.77 A rubber inner bladder held the 

incompressible working fluid, water.78 Under 

high accelerations, the fluid was forced inward 

and downward in the suit, providing sufficient 

pressure on the lower extremities to prevent 

the pooling of blood in these areas while supporting them against centrifugal force.79 This 

allowed the heart to pump sufficient blood to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

87

the head, “thus preventing the occurrence of 

blackouts and unconsciousness and delaying 

the onset of fatigue.”80

Apparently, unknown to Franks, the idea was 

not new. Dr. Heinz von Diringshofen, a medical officer in the part of the German army 

that would become the Luftwaffe, had begun 

researching prolonged acceleration in flight 

during 1931. Using the centrifuge at the Air 

Ministry Aeromedical Research Institute in 

Berlin, Dr. Ruff and Dr. Otto Gauer had been 

working on fluid-filled anti-G suits since late 

1935.81 Centrifugal force acted on the water 

in the suit the same as it did on the blood in 

the body, creating a compensating pressure 

gradient. Thus, the suit reduced the pooling 

of blood in the lower half of the body and 

maintained cerebral circulation.82 However, 

Ruff would later conclude that the “idea of 

using a double-walled, fluid-filled suit (inner 

wall pliable for adjustment to the body surface 

and outer wall rigid), although theoretically 

correct, is practically impossible.”83 Not only 

had the Germans already invented the Franks 

Flying Suit, they had dismissed it as impractical. But Franks did not know this—yet. 

In May 1940, Franks flight-tested the first suit 

using a Fleet 16 Finch biplane trainer (No. 

1021) at Camp Borden. Oddly, this was the 

first time Franks had ever flown, and he was 

initiated with high-speed aerobatics.84 In two 

tests, one at 6.2-G and the other at 7.7-G, the 

onset of blackout was experienced by the pilot, 

Flight Lt. Beer, who was not wearing a suit, 

but not by Franks. The researcher reported, 

“The suit had been cut to fit me perfectly, 

standing up ... in the airplane I was sitting 

down, and when the pressure hit I thought it 

was going to cut me in two.” Franks found the 

suit confining, uncomfortable, and very hot.85

Franks had already considered this possibility 

and quickly redesigned the suit to reduce the 

coverage. During the redesign, Frank replaced 

the laces used in the first suit with zippers to 

make donning and doffing easier. Somewhat 

after the fact, the first suit was designated 

Franks Flying Suit (F.F.S.) Mk I, while the 

second suit became the Mk II. On June 2, 

1940, RAF Wing Commander D’Arcy Greig 

began flight-testing the second suit at Malton, 

Ontario, using an RCAF Supermarine Spitfire 

(L1090).86 Although he reported the suit provided a needed measure of protection, Greig 

believed “the principle involving the design of 

the suit is sound but in its present form it is 

not a practical proposition,” and “many modifications would be needed” before it could be 

used in combat.87 Franks brought an improved 

suit back to Farnborough in February 1941, 

but the trip turned tragic when Banting was 

killed in an airplane crash on February 21 on 

his way to England.

In addition to the suit modifications, it was 

obvious that a safer and more controlled means 

of testing was necessary. Fortunately, Franks 

and George A. Meek had already developed 

preliminary plans for a human centrifuge, 

and in 1940, the National Research Council 

approved funding. When the device opened in 

late summer 1941, it was the fastest and most 

powerful human centrifuge in the world.88

Development of the suit continued, and in 

April 1941, Franks took a prototype of what 

became the Mk III to Farnborough. It was 

the same place that William K. Stewart had 

tested Fulton’s leggings 6 months earlier. RAF 

pilots evaluated the suit using Fairey Battles 

and Hawker Hurricanes and found it could 

“prevent blackout up to 9-G.”89 Despite consistent complaints of discomfort from pilots, 

the evaluation showed the garment performed 

as advertised. A report released on August 

21, 1941, concluded, “In combat the wearer 

of the suit can follow his opponent however 

sharply he turns and still retain his vision 

which will enable him to use his [gun] sights. 

In the pullout from a high speed dive at low 

level a protected pilot will be able to force 

a following opponent to black out or break 

away.”90 However, a second report, written 

by Stewart, found “difficulties” with the suit. 

Most of them concerned comfort, or the lack 

thereof, and the amount of body heat trapped 

by the suit while waiting on the ground.91

Despite its problems, the suit held much 

promise, and the British and Canadians 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

88

ordered it into production. Ultimately, 

Dunlop produced at least 800 Mk III 

suits beginning in September 1941.92 It 

subsequently became the first G-suit to 

be used in combat, by the Royal Navy 

Fleet Air Arm while providing cover for 

Eisenhower’s invasion of North Africa at 

Oran, Algeria, in November 1942.93

Combat trials dragged on for 2 years. Despite 

several early successes, such as the battle at 

Oran, and enthusiastic backing from some 

pilots, British and Canadian fighter pilots 

ultimately judged the Franks Flying Suit 

impractical.94 In 1946, a National Research 

Council study noted that “... certain 

objections were eventually raised against the 

suit, in particular discomfort while ‘at the 

ready,’ and difficulty in turning to search 

for enemy aircraft coming from behind.”95

Franks designed the suit specifically to 

protect its wearer from the effects of 

accelerations without regard for the overall 

operational needs of the pilot. He did this 

based on somewhat faulty logic due to not 

being a pilot. Unfortunately, air combat 

maneuvering was only one aspect of a very 

complex environment. Fighter missions 

also involved long hours in the cockpit, and 

the weight, bulk, and mobility restrictions 

of the suit made pilots reluctant to wear 

it. At the same time, the nature of fighter 

combat had changed since the beginning 

of the war. Rather than engaging in short, 

furious dogfights like those during the Battle 

of Britain, fighter pilots were more likely to 

find themselves escorting bombers over long 

distances: a situation that did not endear the 

heavy and uncomfortable water-filled suits to 

those who had to wear them. In addition, the 

“bounce,” or surprise attack, especially from 

the rear, had become the preferred fighterversus-fighter tactic, and the majority of 

pilots never saw their attacker.96 The restricted 

mobility of the Franks suit made it almost 

impossible for a pilot to turn and look aft, 

making them particularly venerable to attack 

from the rear.

The death knell for the water-filled Franks 

Flying Suit was the testing on the human 

centrifuge at Mayo that revealed that using air 

to pressurize the F.F.S. Mk III provided 2.2-G 

of protection, significantly more than the 

1.5-G it offered when filled with water. 

Researchers at the Mayo Clinic conducted 

this testing in late 1943 and reported it to the 

Office of Scientific Research and Development 

(OSRD) Committee on Aviation Medicine on 

January 19, 1944. Based on this information, 

the pursuit of hydrostatic suits for acceleration 

protection was largely abandoned in favor of 

pneumatic suit systems.97

The major problem with the Franks suit, 

like the German one before it, was the weight 

of the 5 quarts of water. The only possible 

solution to the problem was to remove the 

fluid, and this is exactly what the Americans 

did when they developed a G-suit that used 

compressed air to provide counter-pressure.98

The American suit weighed only 3 pounds 

compared to 18 pounds for the Franks suit.99

American suits made by Berger Brothers 

and David Clark Company quickly replaced 

the Franks Flying Suit in RAF and RCAF 

service. Nevertheless, the forward-thinking 

Wilbur Franks received the Order of the 

British Empire (OBE) in January 1944, 

and the existence of his suit, previously 

kept secret, became public knowledge in 

December 1944.100

Late in the war, the Canadians developed 

the air-activated F.F.S. Mk VI, which was a 

cutaway (or “harness”) G-suit much like that 

developed by the Americans. This suit used 

a single, continuous air bladder to provide 

counter-pressure over the abdomen, thighs, 

and calves. The suit had zippers on the legs 

and abdomen and lacing adjustments on the 

waist, thighs, and calves. The hips and knees 

were uncovered. The cutaway suit could be 

worn under or over standard flying clothes. 

A similar Mk VII suit was a conventional 

set of trousers instead of a cutaway model. 

Although these suits were called Franks 

Flying Suits, three pilots at the Acceleration 

Section in Toronto largely designed them 

and they more closely resembled the 

American G-suits.101
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

89

THE AMERICANS

On December 2, 1940, Maj. Mervin E. Gross, 

the Executive Officer of the Materiel Division 

in Washington, DC, wrote to Dr. Vannevar 

Bush (1890–1974), the chairman of NACA 

asking for assistance in determining the equipment necessary for very high-altitude flying. 

Bush was already a legendary engineer and 

would later become, in effect, the first presidential science advisor during the Cold War.102

Bush responded that the development of a 

pressure suit would allow aircrew to reach 

extreme altitude without imposing the same 

demand on an airplane (primarily weight) 

that a pressurized cockpit would. He believed 

the development of pressure suits for pursuit 

(fighter) pilots was of immediate importance 

and offered suggestions for a pressure suit 

development program along with the full 

cooperation of the NACA. In addition, Bush 

pointed out that the Canadians were already 

developing a water-filled G-suit and suggested 

the Army follow suit. Bush also suggested that 

the Air Corps enlist the services of the OSRD 

Committee on Aviation Medicine.103

In the years leading up to World War II, Australia, Canada, Germany, Italy, and Japan each 

looked to solve the problems of acceleration 

with, at best, marginal results. Not surprisingly, given the enormous resources available 

for the war effort, it was the Americans who 

Although the water-filled Franks Flying Suit Mk III was the 

first G-suit to see combat, pilots and researchers ultimately 

rejected the suit as too uncomfortable for operational use. 

Eventually, the Canadians adopted air-filled bladders with 

the introduction of the FFS Mk VI cutaway suit. These photos 

graphically show why this type of suit was known as a cutaway.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

90

The Frank Flying Suit Mk 

VII used the same air-filled 

bladders as the cutaway 

Mk VI but featured a 

conventional set of trousers 

instead of being a cutaway. 

Some pilots preferred this 

design since they did not 

need to wear flying clothes 

underneath.

Courtesy of the David Clark 

Company, Inc.

ultimately got the science right and produced 

a truly workable G-suit. 

In early 1942, researchers at the Mayo Clinic, 

in Rochester, MN, formed the Aero Medical 

Unit and offered their services to the Army for 

a dollar a year. A contract was formalized in 

February 1942. The original group of researchers included Charles F. Code (1910–1997), 

Edward J. “E.J.” Baldes (1898–1975), and 

Walter M. Boothby (1888–1953). Like many 

during the war years, “We were motivated by 

a high sense of loyalty to our country,” Code 

recalled nearly 40 years later.104

Aeromedical research at the Mayo Clinic was 

already well respected. The 1939 Robert J. 

Collier Trophy, awarded to the “Airlines of 

the United States for their high record of 

safety in air travel,” gave:

... special recognition to Drs. Walter M. 

Boothby and W. Randolph Lovelace, II of 

the Mayo Foundation for Medical Education and Research and Captain Harry G. 

Armstrong of the U. S. Army Medical 

Corps at Wright Field, for their contribution to this safety record through their 

work in aviation medicine in general and 

pilot fatigue in particular.105

The Mayo Aero Medical Unit had two areas of 

primary emphasis: one dealing with the threats 

of the high-altitude environment (lack of oxygen, decompression sickness) and the second 

focused on the threats of acceleration-induced 

blackout and risk related to acceleration in 

general. Boothby headed the high-altitude 

laboratory, formed in 1935, in close collaboration with Dr. William J. Randolph Lovelace II 

and Dr. Arthur H. Bulbulian. Baldes headed 

the acceleration laboratory, formed in 1942, 

and his physician partner was Code.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

91

Code was no stranger to challenges in life. 

He suffered from scarlet fever when he was 8, 

contracted polio at 12, and was told that he 

would never walk, a prediction that turned 

out to be wrong, although he wore back and 

leg braces. After earning a medical degree 

from the University of Manitoba and a Ph.D. 

from the University of Minnesota he turned 

to research. Code was known for establishing 

the role of histamine in allergic reactions 

and his basic research led pharmacologists 

to develop antihistamines.106

Baldes was the head of the biophysics department at Mayo. He earned a Ph.D. in physics 

at Harvard and in physiology at University 

College in London.107

Boothby was the first chairman of the Aero 

Medical Unit, and he interacted formally 

with the Committee on Aviation Medicine. 

In 1907, Boothby and Frederick J. Cotton 

(1869–1938) invented an apparatus to deliver 

nitrous oxide, ether, and oxygen for use in 

anesthesia. Subsequently, Boothby, Lovelace, 

and Bulbulian developed the BoothbyLovelace-Bulbulian (BLB) nasal oxygen mask 

and the later oronasal mask that revolutionized high-altitude flying.108

Dr. William J. Randolph “Randy” Lovelace 

II (1907–1965) studied medicine at Harvard 

Medical School and graduated in 1934. 

He joined the Mayo Clinic for a surgical 

fellowship in 1935 and, having an interest in 

aviation, became a flight surgeon in the Army 

Medical Corps Reserves. His interest in the 

problems of high-altitude flight began during 

his fellowship at the Mayo Clinic. Lovelace left 

Rochester in 1942 to work at the U.S. Army 

Air Forces (USAAF) Aero Medical Laboratory 

and during World War II conducted highaltitude parachute experiments, including one 

jump from 40,200 feet during 1943. In 1958, 

Lovelace was appointed chairman of the NASA 

Special Advisory Committee on Life Science, 

where he played a key role in the selection of 

the Mercury astronauts. NASA appointed him 

Director of Space Medicine in 1964, but he 

died in a plane crash on December 12, 1965.109

Bulbulian’s work as a part of the Mayo Aero 

Medical Unit led to the creation of a series 

of civilian and then, finally, military masks, 

notably the A-14 oxygen mask for the Army. 

The A-14 mask was frost proof and allowed 

the pilot to talk and eat while wearing it. 

Bulbulian also was the first director of the 

Mayo Medical Museum and designed the 

exhibits for the Mayo Clinic’s display for 

the A Century of Progress Exposition at the 

1933 Chicago World's Fair.110

The Mayo Clinic evolved from the frontier 

practice of Dr. William Worrall Mayo 

(1819–1911) and his two sons, William James 

Mayo (1861–1939) and Charles Horace 

Mayo (1865–1939). What is now considered 

the Mayo Clinic was founded by the Mayo 

brothers and a group of six other doctors, 

including Dr. Henry Stanley Plummer 

(1874–1936), who is considered by many 

American physicians to be the “architect of 

the modern medical practice” and a primary 

reason for the Mayo Clinic’s early success.111

While the Mayo brothers excelled as surgeons, 

Plummer established the diagnostic, clinical, 

and, in part, the organizational aspects of 

the practice. He also designed many of the 

systems now in use around the world, such 

as individual dossier-style medical records. In 

1919, this group created the Mayo Properties 

Association, and their private practice became 

a not-for-profit entity. The Mayo brothers, 

who had retained ownership of all clinic 

properties and furnishings, ceded all of their 

assets to this newly formed association. 

Code and Baldes recruited Dr. Earl H. Wood 

(1912–2009), to run the newly completed 

human centrifuge at Mayo. After Pearl 

Harbor, Wood tried to volunteer for the Army 

Air Forces but remembered, “They refused 

me, because I was considered essential to 

teach medical students.”112 He was teaching 

at Harvard Medical School when Baldes 

and Code recruited him back to his native 

Minnesota with the promise that he could be 

in charge of the centrifuge.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

92

Wood quickly realized that tests with animals 

could not provide sufficiently accurate information. In fact, “We had to experiment on 

ourselves,” he said, because “we would never 

do anything on any subject that we didn’t first 

do on ourselves.”113 In the end, Wood rode 

the centrifuge so many times that he most 

likely had more blackouts in controlled conditions than any other subject. Code would later 

comment, “There wasn’t anything we did then 

that was safe.”114

Wood, realizing how incomplete the scientific 

explanations for the blackout problem were, 

quickly ascertained the true major problem. 

By comparing blood pressure at heart and 

head levels in the centrifuge, he learned that 

the heart could not generate sufficient pressure 

to pump blood to the head during periods of 

high acceleration. At 5-G, blood weighs five 

times as much, overwhelming the heart’s ability to move it, so blood pressure in the head 

at 5-G is virtually zero. During his research, 

Wood found that the force exerted by a tight 

turn or a dive recovery could drive the diaphragm and the heart down toward the feet as 

far as 2 inches. That meant the heart had to 

generate even more pressure to pump blood 

up to the brain. Compressing veins, as done 

by a water-filled suit, was not the answer; 

instead, arteries needed to be compressed to 

increase arterial pressure.115

BERGER BROTHERS

The Berger Brothers company was based in 

New Haven, CT, and had three major subsidiaries: Spencer Inc., also in New Haven; Spencer Supports (Canada) Ltd, in Rock Island, 

Quebec; and Spencer (Banbury) Ltd. in 

Banbury, England. The brothers were Darwin 

Spencer Berger and George Wendell Berger, 

and Darwin’s son, Spencer Merriam Berger.116

Beginning in the 1920s, the Spencer companies sold “individually designed supports for 

abdomen, back, and breasts.”117 The products 

seemed far removed from aviation.

While William Stewart was testing John 

Fulton’s leggings at Farnborough in 1940, 

the idea caught the interest of an American 

who happened to be at the base. Frederick 

D. Moller was an experienced pilot with more 

than 3,000 flight hours, and he immediately 

recognized the potential of the concept but 

believed the entire outfit needed to be 

simplified. He proposed combining an 

abdominal belt, leggings, and inflatable sleeves 

into a single garment that would be easier to 

don than Fulton’s three-piece ensemble. An 

intricate set of tubes sewn into the garment 

allowed inflation from a single pneumatic 

source.118 Upon his return to the United States, 

Moller took this idea to Berger Brothers, but it 

is unclear if Moller had a previous relationship 

with the company.119

Based largely on Moller’s enthusiasm, Berger 

Brothers—makers of corsets and surgical 

supports—became interested in “foundation 

garments” for pilots. Urged on by Moller, 

the brothers decided, without consulting the 

Government, to begin developing an inflatable 

garment that would provide positive control 

of the splanchnic area, a strong support for the 

spinal column, and a safeguard against hernia. 

The company began using principles already 

employed in the Spencer Abdominal Support 

Belt, a device the company sold to the medical 

profession.120 It did not take long for the 

Government to notice.

Eventually, Moller and Irving “Doc” Versoy 

produced a simple pneumatic belt and leggings in cooperation with LCDR Leon D. 

Carson from the U.S. Navy and with the 

assistance of the National Research Council. 

The first suit was a set of fitted coveralls with a 

group of air bladders in the calves, thighs, and 

abdomen. Zippers, laces, and internal straps 

allowed the suit to be adjusted to fit. The 

20-pound suit progressively pulsated in seven 

zones from the ankles to the abdomen.121

Initially, the pilot inflated the ensemble by 

hand just before he expected to need it, but 

like Poppen’s earlier experiments, this quickly 

proved impractical. 

The Mayo Clinic evaluated the Berger Brothers 

suit using a tilt table since the human 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

93

centrifuge was not yet operational. These tests 

revealed that the suit provided approximately 

1-G under the best circumstance, but the military considered this adequate. Even at 1-G protection, the suit allowed pilots to increase the 

tolerance from 5-G to 6-G, a small but potentially important advantage in aerial combat. In 

mid-1941, the Navy ordered a few hundred 

suits for use in the Pacific, but there is no evidence that they ever saw combat.122

Further development resulted in the 10-pound 

G-1, which, consisted of tight, high-waist 

trousers with built-in suspenders and a girdle 

containing 17 air bladders in 3 pressure 

zones.123 Like the original suit, the G-1 provided the highest pressure over the ankles, an 

intermediate pressure over the calf area and 

abdominal belt, and the lowest pressure over 

the thighs. Engineers at Spencer designed a 

valve that operated off the same engine-driven 

air pump that provided vacuum to instruments in the cockpit. The Type B-2 or B-3 

vacuum pump used by the Vought F4U-1 

Corsair and Grumman F6F Hellcat already 

supplied air pressure for a variety of purposes, 

including operating de-icer boots and preventing air locks in external drop tanks. The 

smaller B-2 pump rapidly lost the ability to 

pressurize the suit above 20,000 feet, although 

the larger B-3 pump remained effective to 

about 30,000 feet.124

From the positive side of the pump, air passed 

through an oil vapor separator on its way to 

the cockpit through a 0.625-inch tube to the 

inlet of the gradient pressure valve assembly. 

The operation of the valve was completely 

automatic. The air came into the distributing head of the control valve and a bellows 

unit held the valve closed until acceleration 

exceeded 1.5-G. From the control valve, air 

traveled to the 3-G-compensated gradientpressure valves actuated by weights and 

syphons as a function of acceleration. The 

gradient valve nearest the control valve was 

the high-rate valve that controlled the ankle 

bladders. Next was the intermediate valve that 

controlled the calf area and abdominal bladder. Last was the low-rate valve that transmitted air to the thigh bladders. Once properly 

adjusted for their specific installation, the 

valves required no routine servicing.125

Because the vacuum pump could not provide 

sufficient pressure quickly enough to fill a 

completely depressurized set of bladders, the 

suit always contained approximately 0.8 psi. 

The suit began pressurizing at 1.5-G at a 

rate of a little over 1.1 psi per G. At 4-G, the 

suit provided 3.5 psi on the ankle bladders, 

increasing to 7.9 psi at 8-G; the other bladders had correspondingly lower pressures. The 

Seamless Rubber Company in New Haven, 

CT, manufactured the bladders, which were 

generally similar to hot-water bottles made by 

the company.126

The Berger Brothers G-suit consisted of a set of high-waist 

trousers and suspenders with a series of inflatable bladders 

sewn inside. The suit had three zippers, one running from the 

top of the waist down to the bottom of each ankle (#1 and #2) 

and another running from the top of the waist to the bottom of 

the crotch (#5). Various sets of laces (#7, #8, and #11) allowed 

each suit to be tailored for its wearer. 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

94

Each Berger Brothers G-suit used 17 air bladders in three 

pressure zones to provide counter-pressure on the legs and 

abdomen. Since the aircraft vacuum pump could not deliver 

sufficient volume quickly enough to fill all of the bladders, 

the suit always contained about 0.8 psi, making it somewhat 

uncomfortable when worn for prolonged periods. Although 

the suit afforded a decent measure of protection against 

blacking out under acceleration, the pilots universally disliked 

it (and all other contemporary suits). 

Courtesy of the David Clark Company, Inc.

In addition to its inflatable bladder, the 

abdominal belt supported the back and internal abdominal organs, much like a hernia belt. 

The inflation of the rubber bladder within the 

nonstretching fabric belt diminished the area 

within the abdomen where blood could pool. 

If the pilot felt his vision “graying out,” he 

could push hard with the abdominal muscles 

against the belt; the tension of the belt made 

the maneuver more effective than shouting or 

tensing without a restraint.

Berger Brothers provided suits in four sizes: 

small short, small long, large short, and large 

long. The suit had three zippers, one running 

from the top of the waist down to the bottom 

of the ankle on each leg, and another running 

from the top of the waist to the bottom of the 

crotch. To don the suit, all three zippers were 

opened completely and then zipped closed 

around the pilot. A set of adjustment laces was 

located on the front of each calf and the back 

of each thigh to allow each pilot to tailor the 

suit as needed. Generally, once the adjustment 

laces were set for a pilot, they were not used 

again, with the pilot donning and doffing the 

suit using only the zippers. The user manual 

said “Bear in mind that, while a snug adjustment makes the suit more efficient, it is not 

necessary for it to be uncomfortably tight 

under any conditions.”127

Centrifuge tests at Mayo showed that the 

Berger Brothers suit provided sufficient 

protection, and the military did not seem terribly worried about possible discomfort caused 

by the suit always being slightly pressurized, 

although the pilots would later decide otherwise.128 In December 1943, the Army ordered 

22 G-1 suits from Berger Brothers, along with 

the equipment required for aircraft, and sent 

them to the Eighth and Ninth Air Forces in 

England. Based on the initial pilot reactions to 

the suits, the Army ordered 1,000 production 

suits, although ultimately only 500 would be 

delivered before the suit was replaced by the 

improved G-2.

In addition, Navy fighter squadron VF-8 

“Ghost Cats” tested the G-1 during combat 

in the Pacific flying Grumman F6F-3 

Hellcats off the USS Bunker Hill (CV-17) in 

September 1943 and again during the attack 

at Palau in March 1944. Pilots involved in 

the combat attributed several victories over 

Japanese Mitsubishi A6M Zero fighters 

specifically to the advantage provided by 

the G-suits. In general, the pilots liked the 

protection provided by the suits but thought 

they were too hot and cumbersome. Many 

pilots also worried what would happen if 

they had to bailout over water while wearing 

the ensemble—the additional 10 pounds of 

equipment would not help flotation. The 

result was that pilots seldom wore the suits 

after the initial novelty wore off. Based on 

pilot comments, LCDR Harry Schroeder 

made several suggestions to the Naval Air 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

95

Crew Equipment Laboratory on how to 

simplify the suit and its equipment. The Navy 

subsequently sent this information to the 

Aero Medical Laboratory at Wright Field.129

The reluctance of pilots to accept the G-1 suit 

forced the military to go back to the drawing 

board. Based on testing with single-pressure 

David Clark Company suits at Mayo Clinic, 

the Army decided to forego the gradient pressure concept and settle on a simple, singlepressure garment. Berger Brothers, David 

Clark Company, and Mayo Clinic all cooperated in the development of the G-2 suit. Outwardly, the suit generally resembled the G-1, 

consisting of a set of high-waist trousers with 

suspenders. However, instead of the 17 bladders in the G-1 suit, the G-2 contained only 

5 bladders, and weighed 6.5 pounds instead 

of 10 pounds. The bladders consisted of one 

rectangular unit over each calf and thigh, plus 

an abdominal bladder.130

The pressurizing valve for the G-2 was different from the gradient pressure valve used by 

the G-1. Under normal 1-G flight conditions, 

the valve did not provide any air to the G-suit, 

keeping it completely depressurized. However, 

once acceleration exceeded 1.5-G, the valve 

rapidly increased pressure at the rate of 1 

psi per g, meaning that at 9-G the valve was 

providing 7.5 psi to pressurize the suit. Other 

than connecting the inflation hose to the valve 

prior to flight, there was no pilot interaction 

with the device. This valve became standard 

equipment on many midproduction Lockheed 

P-38 Lightnings, Republic P-47 Thunderbolts, and North American P-51 Mustangs 

that used B-11 or B-12 vacuum pumps. 

Unfortunately, the B-11 and B-12 pumps 

suffered the same altitude limitations as the 

earlier B-2 and B-3 pumps, respectively.131

On the Mayo Clinic centrifuge, the suit provided 1.4-G of protection, and researchers 

at Wright Field generated similar results on 

their centrifuge. Service trials at Eglin Field in 

February 1944 were satisfactory, and the Army 

standardized the G-2 suit on June 19, 1944. 

Within the next year, the military distributed 

more than 3,500 G-2 suits, made by a variety 

of manufacturers, to combat zones.132

Nevertheless, much like its predecessor, combat pilots did not meet the G-2 with overwhelming enthusiasm. The reports from the 

pilots, however, contained at least one very 

interesting observation. Most of the pilots 

refused to use the G-suits as their only clothing and instead wore the G-suit over their 

normal flying uniforms. Despite pilots not 

using the suits as intended, they worked.133

The G-1 consisted of a set of high-waist trousers that 

contained the air bladders for the legs and abdomen. The 

progressive feature of the suit, where different pressures were 

applied to different parts of the body progressively, led to a 

large and complex set of valves, shown on the table next to the 

model. The three pressure valves (one to the left and two to 

the right of where the hoses connect) each provided a different 

pressure. There were several variants of this valve arrangement, but they all operated similarly. 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

96

THE WORCESTER CONNECTION

Engineer and test pilot A. Scott Crossfield 

once described David Clark as “one of the 

most interesting men I have ever met in the 

aviation world.”134 David M. Clark was born 

in Massachusetts in 1903 and left school at 

age 15 to go to work full time. Nevertheless, 

he continued taking accounting and business 

classes in the evening, mostly at the urgings 

of his father. In 1934, he founded a knitting 

business in Worcester, MA, also with the 

encouragement of his father. Not having sufficient capital to start the company on his own, 

Clark convinced two older friends to help 

finance the endeavor in exchange for equal 

ownerships in the company. The business 

apparently suited Clark and, in quick order, 

he received six patents for improved knitting 

techniques. Although making a good living 

from the knitting business, Clark developed 

a fascination with aviation and, with a World 

War on the horizon, sought ways to contribute. Taking his cue from the “dreaded blackout” portrayed in newsreels of the time, Clark 

decided, sometime during 1940, to develop a 

garment that could protect aviators from highG environments, apparently unaware of similar efforts by Cotton, Franks, and Moller.135

One of Clark’s products was a knitted elastic 

support undergarment for men called the 

“Straightaway,” for which he used an innovative technique to change the knitting from 

ordinary to elastic fabric at the waist, resulting in an undershirt attached to an elastic 

The G-2 G-suit, this one made by David Clark Company, 

was a major improvement over the original G-1. Introduced 

into combat in mid-1944, the G-2 contained only 5 bladders, 

compared to 17 on the G-1. More importantly to the pilots, 

the weight of the suit was reduced from 10 pounds to only 

6.5 pounds. This G-suit found use in most front-line fighters 

and provided about 1.4-G of protection. Despite all of 

the improvements, one thing the new suit shared with its 

predecessor was that pilots universally disliked it.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

97

abdominal support. This knitting technique 

eliminated the cross seams that typically 

caused discomfort. It was an innovative garment for the time, and the Straightaway was 

the subject of one of Clark’s patents. For 

reasons unknown, Clark decided he could 

modify the Straightaway into a garment that 

could help pilots avoid blacking out.

Lacking money to travel, Clark wrote letters 

to the Army Air Corps and Navy Bureau of 

Aeronautics, but received no responses. He 

also paid a traveling stationary salesman friend 

$50 to show the Straightaway to the military. 

The particular Straightaway that Clark had 

supplied for this trip had an inflatable football 

bladder sewn into the center of the lower part 

of the abdomen that would apply pressure and 

help the aviator with the standard grunting 

techniques commonly used to combat loss of 

consciousness during high-G maneuvers. Like 

several earlier concepts, the bladder needed to 

be inflated using a hand bulb before the pilot 

anticipated he would need the support.

Apparently by shear chance, the salesman 

managed to gain an appointment with Jack 

Poppen, who was seemingly impressed with 

the garment but not with its operation. Poppen wrote Clark a few days later explaining 

the concept would not work because “it 

lacked automaticity that I cannot tell you 

about.”136 By this time, Poppen was well 

familiar with the automatic valve used on the 

Berger Brothers suit, but security restrictions 

prevented him from discussing it with Clark. 

Perhaps it was just as well since this forced a 

separate development effort—competition is 

always a good thing.

Clark, correctly, interpreted this to mean that 

he needed a way to automatically inflate the 

bladder based on changing flight conditions 

and began a search of a suitable G-valve. Clark 

built a prototype using iron pipe, a domestic 

water valve, and a miniature bicycle pump. 

When swung around vigorously at arm’s 

length, the device would inflate a football 

bladder very quickly; the bladder deflated 

when the swinging stopped. Soon, Clark 

connected the valve to his modified Straightaway via a pair of 10-foot hoses hooked to a 

compressed air cylinder. Unfortunately, by 

this time, November 1941, the Navy had 

transferred Jack Poppen to a new duty station 

and his replacement, LCDR Leon D. Carson, 

expressed no interest in the device since the 

Berger Brothers gradient-pressure G-suit was 

already in limited production.

Finding no encouragement from the military, 

Clark wrote letters to the various aircraft 

manufacturers describing his garment. Only 

one responded, Boeing Chief Test Pilot 

Edmund T. “Eddie” Allen, who confirmed 

that some sort of G-protection was necessary 

and suggested that Clark contact Maj. Otis 

O. Benson, Jr., the chief of the Aeromedical 

Research Unit (soon to become the Aero 

Medical Laboratory) at Wright Field. A business trip a few days later brought Clark near 

Wright Field, so he made an unannounced 

visit. After a few bureaucratic hurdles, Clark 

and Benson were introduced. Clark explained 

that he was not seeking contracts but wanted 

to work with a group that understood the 

scientific principles, could evaluate his efforts, 

and offer advice for improvements. The prototype suits would be pro bono since that is how 

the commercial clothing business worked; 

companies made prototypes to show to clients 

and recouped the development costs via production orders. Benson thought this a worthwhile idea and arranged to have Clark issued 

the appropriate security clearances.137

In the continuing connection to Mayo, Benson 

had spent a year at the clinic in 1939 studying aviation physiology. Afterward, Benson 

attended Harvard University to continue his 

study of aviation physiology. He became the 

second chief of the Aero Medical Laboratory 

and, still later, commandant of the new School 

of Aerospace Medicine at Brooks Air Force 

Base (AFB), TX.138

In the late summer of 1941, Benson suggested 

Clark contact Dr. Hudson Hoagland, at the 

Physiological Laboratory of Clark University 

in Worcester, MA, who had recently presented a paper on acceleration protection.139

Hoagland would leave Clark University in 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

98

1944 and, with Gregory Pincus, found the 

Worcester Foundation for Experimental Biology, now called the Worcester Foundation for 

Biomedical Research.140 It is best known for 

the development of the combined oral contraceptive pill by Pincus and Min Chueh Chang. 

The institution merged with the University of 

Massachusetts Medical School in 1997.141

Benson and Hoagland both suggested that 

Clark contact LT Thomas J. Ferwerda at Naval 

Air Station (NAS) Anacostia in the District 

of Columbia. Ferwerda had a prototype 

G-suit, which he called a “Pulsatile” pressure 

suit, that was ready for testing on the newly 

opened human centrifuge in Canada. The 

suit consisted of a heavy open-weave material 

with seven bladders positioned crosswise in 

each leg. The pressure pulsated in a wave, 

traveling from the ankles to the thighs. The 

suit was tested by the Navy at Cecil Field, FL, 

in November 1942 but proved disappointing. 

Ferwerda subsequently modified the suit to 

include bladders along the arms and abdomen, 

but this suit also proved disappointing.142

However, perhaps the most important suggestion from Benson and Hoagland was to 

contact E.J. Baldes at the Mayo Clinic, who 

was also developing a human centrifuge. 

David Clark had already made preliminary 

contact with Mayo, sending it a Straightaway 

for evaluation as a postsurgery abdominal 

support. An exchange of correspondence with 

The second G-suit designed by LT Thomas Ferwerda 

included air bladders along the legs, arms, and abdomen that 

progressively inflated (or pulsated). Ferwerda, like Berger 

Brothers and David Clark, was convinced that progressively 

inflating a suit from the ankles to the thighs (and wrists 

to shoulders) would force blood from the extremities back 

toward the heart. It was a concept that worked in theory but 

had little practical effect.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

99

Charles Code at Mayo led to Clark mentioning his conversation with Benson regarding 

Baldes. Eventually, word reached Baldes, 

who invited Clark to visit him in Rochester, 

MN. In a November 1941 meeting, Baldes 

showed Clark a scale model of the centrifuge, 

which had a construction budget of $50,000 

despite the $1-per-year contract Mayo had 

with the Government. Unusually, Clark had 

not brought his suit and valve with him but 

described the device to Baldes, who approved 

of the basic concept.143

During his discussions with Baldes, Benson, 

and Hoagland, David Clark determined that 

ideally a G-suit should “milk” the blood from 

the lower legs up toward the torso since a 

simple belly bladder might not be sufficient 

to delay loss of consciousness. Unknown to 

Clark, this was not a new concept; the progressive or gradient suits developed by Frank 

Cotton in Australia and Fred Moller at Berger 

Brothers shared a similar trait. 

Back in Worcester, Clark developed a “bandage” 

he could wrap around his legs. Hooked to 

a 50-psi air source, this bandage inflated 

progressively from the ankle upward, forcing 

blood from the legs into the torso. Clark 

demonstrated the garment for Baldes and 

Code in Worcester as they passed through on 

their way to convince Earl Wood at Harvard 

to join the human centrifuge program at the 

Mayo Clinic.144

During 1941, Ernest L. Olrich, the president 

of Munsingwear,145 another clothing manufacturer, purchased a majority stake in the 

David Clark Company by buying out the two 

older partners. David Clark kept 30-percent 

of the shares, the title of treasurer, and, by 

agreement, absolute control of the company. 

Clark’s relationship with Olrich later assisted 

the human centrifuge under construction 

at Mayo. After the Japanese attack on Pearl 

Harbor, the nation went on strict rationing 

of “luxury items” that contained war-critical 

materials. This included automobile tires. As 

designed, the Mayo centrifuge used an automobile tire to transfer power from a Chrysler 

drivetrain to the flywheels that drove the 

centrifuge; because of the rationing, it was 

impossible to acquire tires without violating the security restrictions surrounding the 

project. Clark knew the Government had 

appointed Olrich the chief of rationing for 

Minnesota, and he quickly arranged the delivery of two new tires to Mayo.146

Another of Clark’s contacts proved handy 

when it came time to design a more sophisticated valve to operate the G-suit. Henry 

Wilder, an engineer at the Heald Machine 

Company, also located in Worcester, had 

been a Boy Scout with David Clark. After its 

founding in 1826, Heald specialized in precision grinding machines, especially ones that 

shaped the inside surfaces of hollow, cylindrical parts. At its peak, the Heald Machine 

Company had more than 1,300 employees 

and occupied nearly 500,000 square feet of 

factory space, but it ultimately closed its doors 

in 1992.147

Clark’s original water-supply valve had an 

important failing; if the source pressure varied, so did the output pressure. This was not 

a huge issue during desktop and laboratory 

demonstrations in which compressed air supplied the source pressure, but it would be a 

major concern in an airplane. Along with 

another engineer at Heald, Waldo Guild, 

Wilder developed a valve that was immune 

to the variance of source pressure. The valve 

could easily supply an inflation pressure of 

1 psi per G. It was a workable, if large and 

heavy, solution to pressurizing a G-suit.148

To create a more sophisticated anti-G garment, Clark needed somebody that could 

sew better than he could. Julia Greene was 

the daughter of Irish immigrants and a few 

years older than Clark. Greene already worked 

for Clark and was easily convinced to help 

develop the garment. The new G-suits started 

conventionally enough; Clark purchased six 

khaki twill coveralls, two each of three sizes, 

in a store downtown. Greene altered the coveralls to provide a tight fit in the buttocks and 

sewed inflatable bladders into the lower legs, 

thighs, and belly. These became the first Progressive Arterial Occlusion Suits (PAOS).149
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

100

The abdominal bladder was there not to 

compress abdominal arteries but to reduce 

the downward movement of the diaphragm 

and heart by supporting the abdominal 

wall. Experimentation with different sizes 

of orifices between the various bladders led 

to a configuration where, at 2-G, the suit 

would inflate progressively to 20 psi at the 

ankles, 10 psi at the knees, 5 psi at the hips, 

and 1.25 psi at the top of the belly.150

The Mayo Clinic had not yet completed 

the human centrifuge, so Baldes and Wood 

tested Clark’s suit using the same tilt table 

researchers had previously used to test the 

first Berger Brothers suit. The two doctors 

believed the suits might be able to provide a 

level of G-protection greater than that provided by the Berger Brothers suit and asked 

Clark to leave them for further testing.

In November 1942, David Clark witnessed 

the researchers at Mayo testing his G-suits 

on the newly completed centrifuge. Earl 

Wood was the first to try the coveralls in the 

centrifuge and found that they provided measurable protection. Dr. Edward H. Lambert 

(1915–2003) then tried them, with the same 

results. David Clark also got a couple of runs 

at 5-G, providing valuable experience for the 

man that was designing the garment. Tests 

showed the PAOS could increase tolerance up 

to 3-G, meaning that a pilot that normally 

blacked out at 5-G could tolerate 8-G with 

the suit. This was significantly better than the 

1-G provided by the Berger Brothers suit.151

David Clark returned to Worcester and began 

designing a new G-suit. Despite the relative 

success of the Mayo tests, each of the subjects had emerged from the centrifuge with 

petechiae (small bruises) on their skin 

where the bladders inflated. Wood thought 

these might be an indication of too much 

pressure, or perhaps the friction of the latex 

bladders which had to stretch considerably 

as they inflated, caused the bruises. Clark 

revised the size and shape of the bladders, 

and switched to a dipped, rubber-coated 

material to eliminate most of the stretching. 

The “milking” idea of progressively inflating 

the suit from the ankles upward did not seem 

to elicit any positive (or, for that matter, 

negative) comments from the researchers. 

Although Clark still believed the idea was 

potentially valuable, it also added considerable 

complexity, and he eliminated it from the 

next prototype suits. These changes resulted 

in the Arterial Occlusion Suit (AOS).152

The AOS was a pair of high-waist trousers 

with five interconnected air bladders: two 

fitted around the calves, two around the 

thighs, and one on the abdomen. They began 

to inflate at 1.5-G to compress the arteries 

in the lower half of the body, increasing the 

blood pressure in the upper half almost instantaneously. In essence, the suit worked 

on the principle of a tourniquet, placing 

strong encircling pressure on each thigh to 

stop the blood circulation to the limbs when 

the pilot experienced acceleration.153

The first AOS provided about 2-G of protection and eliminated much of the petechiae 

seen with the original PAOS. Although this 

was less protection than the PAOS provided, 

it was still twice that provided by the standard 

Berger Brothers suit. However, the researchers ultimately determined the suit was not 

acceptable because of the length of time it cut 

off circulation to the limbs during prolonged 

maneuvers and the resulting discomfort. Still, 

it demonstrated the concept was workable.154

After these tests, David Clark realized he 

needed some method of keeping track of the 

suit designs, so he retroactively called the original PAOS suits Model 1 and the first AOS 

suit the Model 2.155 Each of the two-dozen 

Clark experimental G-suits that followed was 

different, sometimes vastly so. In one model, 

there were arm cuffs that provided measurably better protection but at a huge increase 

in complexity, and they also severely restricted 

the mobility of the pilot’s arms. Often, the 

suits were similar except for the size of the 

abdominal bladders: the otherwise identical 

Model 5 used a 1.5-liter bladder, the Model 6 

used 1.0-liter bladder, and the Model 8 used a 

whopping 4.0-liter bladder.156
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

101

These early rounds of centrifuge studies 

provided some surprising results that guided 

the development of future G-suits. Researchers discovered that the chief factor in suit 

protection was the application of pressure on 

the abdomen and trunk. Pressurizing the legs 

was necessary for the effective use of abdominal pressure, but the amount of pressure was 

not particularly critical. The simplest type of 

leg bladders should be used, “since it is necessary only that they be of such size as to ensure 

reasonable pressure transmission to the legs in 

spite of relatively wide variations in fit.”157

A conference was held at Wright Field to discuss whether a G-suit, better than the Berger 

Brothers garment used by the Navy, existed 

that the Army could field in relatively short 

order. David Clark, Charles Code, and Earl 

Wood attended, and the Mayo researchers 

believed the AOS could fill the need. Clark 

was not so certain, feeling the suit was overly 

complicated and probably not sufficiently 

comfortable for long-term use in a combat 

zone. In addition, the Heald valves were large, 

heavy, and designed to operate off a fixed 

Left: The David Clark Company Model 8 Arterial Occlusion 

Suit (AOS) used bladders on the abdomen and around the 

thighs. Like all of the AOS suits, the thigh bladders functioned 

almost as tourniquets, increasing the blood pressure in the 

upper half of the body almost instantly. Researchers, however, 

worried about the effect of cutting off circulation to the lower 

legs and pilots objected to the discomfort during maneuvering.

Right: This variant of the AOS used a pair of arm cuffs, in 

addition to the abdominal and thigh bladders, in an attempt 

to keep as much blood volume as possible near the heart. Pilots 

found these made it nearly impossible to hold the control stick 

during maneuvering, and the concept was quickly dropped. 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

102

The Cornelius control valve 

for the World War II G-suits 

was ingeniously simple. A 

counterweight reacted to 

G-load and operated a valve 

that either allowed compressed air to enter the suit 

or for the suit to exhaust the 

air as needed. Considering 

that it contained no electronics or complicated feedback loops, the valve was 

remarkably accurate.

Courtesy of the David Clark 

Company, Inc.

50-psi source, not whatever source existed 

on an airplane.158 The conference reached no 

particular conclusion.

Finding a pressure source on airplane—before 

the advent of jet engines and their omnipresent bleed air—was a challenge. The Berger 

Brothers suits used the aircraft instrumentation vacuum pump. Unfortunately, this small 

pump only provided 14.7 psi at sea level, 

meaning the suit had to be kept partially 

inflated (about 0.8 psi) at all times in order 

to react quickly enough to G-loads. This 

increased the discomfort level of the suit on 

long missions since it somewhat restricted 

movement in the cockpit.159

During the Wright Field conference, it 

became obvious that the Heald valves that 

David Clark was using would not work in 

an operational environment. Baldes turned 

to Richard Cornelius in Minneapolis, who 

was working with Mayo and Wright Field 

on pressure-sensitive switches for parachutes. 

In addition to designing various air compressors for aviation applications during World 

War II, Cornelius founded a company that 

has become one of the world’s leading 

suppliers of beverage dispensing equipment, 

including a foam-free draught system for 

beer. Cornelius soon developed a suitable 

valve under the guidance of David Clark and 

the researchers at Mayo Clinic.160
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

103

In 1943, Baldes arranged for the Army to 

bail a Douglas A-24, essentially an olive-drab 

version of the Navy SDB-3A Dauntless dive 

bomber, to the Mayo Clinic for in-flight 

evaluation of G-suits. Showing a good sense 

of humor, the researchers named the airplane 

the G-Whiz.

161 Lambert instrumented the 

airplane, and the chief of the Army Reserve 

contingent in Rochester, Lt. Kenneth Bailey, 

assisted Mayo with maintenance and flying duties. Bailey soon learned to fly precise, 

repeatable profiles that allowed researchers to 

acquire the necessary data.162

Most of the prominent researchers in the 

field of G-protection and Government 

leaders from the USAAF, U.S. Navy, RCAF, 

and RAF, convened at Wright Field in early 

1944 to plot the course for pilot protective 

clothing for the rest of the war. One of the 

decisions that came out of this conference 

was that the Allies would adopt the simplified Berger Brothers G-suit. Although most 

present apparently agreed that the Clark AOS 

provided greater protection, they deemed the 

Berger Brothers suit adequate, and the pilots 

preferred it. After the meeting, Earl Wood 

went to Worcester to tell David Clark.

David Clark was not ready to give up. Overnight, he fabricated a prototype that took the 

best of the Berger Brothers suit and the AOS. 

It had a one-piece bladder system that combined all five bladders, in the Berger Brothers 

suit. The inflation hose passed through the 

belly bladder and branched through the thigh 

sections and into the calf sections to ensure 

the folds of the two layers of fabric could not 

occlude the flow. Clark carefully shaped the 

belly bladder to ensure it would not provide 

uncomfortable contact with the pelvic or rib 

bones when inflated.

When Earl Wood arrived the following 

morning to say his goodbyes, Clark showed 

him the experimental suit. Wood found it 

quite comfortable, even at full inflation. He 

cancelled his outbound train, told Clark 

to make a “more finished” suit, and called 

Charles Code. Within a few days, Julia 

Greene and fellow seamstress Rose Arlauskas 

made three of the new suits in various sizes. 

Wood took the new suits to the Mayo Clinic 

and found that the suit provided adequate 

protection when inflated at 1 psi per G.

Researchers tested the new suit in the Mayo 

A-24, and James Henry came from USC to 

evaluate the suit in the airplane. Lambert had 

installed movie cameras in the airplane so that 

researchers could review the subjects’ reactions 

to the suits after landing. By now, Bailey had 

pretty much perfected the art of taking the 

lumbering dive bomber up to 10,000 feet, putting it in a spiral dive, and producing whatever 

G-load was required for about 15 seconds.

Coincidences are often critical. As Mayo was 

testing the suit, E.J. Baldes phoned David 

Clark with news that he had met Harry 

Schroeder, the man that had evaluated the 

effectiveness of the 300 Berger Brothers G-1 

suits the Navy had sent to combat squadrons 

in the Pacific. Baldes steered Schroeder to 

Worcester, where he met Clark in July 1944. 

Schroeder stressed that the Berger Brothers 

suits had worked well, when the pilots 

One of the features of the 

David Clark Company 

G-suits that made them less 

expensive to fabricate and 

easier to maintain was their 

bladder system. By molding 

many of the interconnected 

bladders as a single piece, 

leakage was minimized, as 

was a lot of hand assembly. 

These are some of the molds 

used to make the bladders 

during 1945.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

104

conceded to wear them—all were reluctant. 

The suits were hot in the tropical climates, 

uncomfortable, too heavy, and did not 

contribute to survival if the pilot abandoned 

his airplane for some reason.163

David Clark listened intently, and when 

Schroeder left for Wright Field a few days 

later, he had an improved suit that weighed 

only 3.5 pounds. The new coveralls did not 

use lace adjustments but had several zippers 

that allowed it to fit each pilot. Testing in 

the Wright Field centrifuge revealed the suit 

provided adequate protection, but Schroeder 

had several ideas to improve the suit, mostly 

to make it more appealing to the pilots. He 

had Clark add a large pocket on the front 

of each shin, a smaller pocket for a hunting 

knife on the inside of the right shin, large 

chest pockets that were out of the way of the 

parachute harness, and a pocket for a pack of 

cigarettes on the upper left arm. David Clark 

developed eight standard sizes (four waist 

sizes in 2-inch gradients, with “shorts” and 

“longs” in each size).164 These changes satisfied 

Schroeder, and he took the modified G-suit to 

Washington. Schroeder named the new suit 

Z-1, the Army designated it G-2, and both 

suits were ordered into production from a 

variety of manufacturers.165

Sometimes a completely different idea comes 

from an unexpected source. Back in early 

1943, Helen Lester and David C. Spooner 

at the Electric Blanket Division of General 

Electric (GE) had contacted Harry Schroeder 

with an idea for a G-suit, developed in 

consultation with Dr. Harold Lamport at Yale 

University. General Electric used capstans 

on the calves and thighs instead of bladders, 

making it more comfortable for the pilots 

(the stomach bladder remained). The capstans 

were large inflatable tubes that ran vertically 

along the legs on the outside of the suit. Each 

capstan attached to a series of interdigitizing 

laces that encircled the limb; as the capstan 

inflated, it tightened the laces around the 

limb and provided the required skin pressure. 

For this to work, the suit had to fit almost 

perfectly. A loose fit would easily allow the 

capstans to exceed their useful limit without 

tightening the laces sufficiently to exert any 

pressure on the skin. A tight fit provided too 

much counter-pressure, potentially shutting 

off circulation to the limb.166

Unfortunately, testing at both Wright Field 

and Mayo Clinic showed the initial suit 

provided no measureable protection. The 

major problem was that the capstans and 

interdigitizing laces could not react quickly 

enough given the available pressure. After the 

tests, sometime in early 1944, Helen Lester 

visited David Clark to discuss the capstan 

system.167 David Clark told Lester about 

the USC centrifuge, and the GE team took 

their suit to California where James Henry 

was working on a partial-pressure suit. 

Unfortunately, tests at USC also showed the 

GE suit provided no measureable protection. 

By the end of the war, the Pioneer Products 

Division of GE had evolved the concept into 

the L-12 suit, which, provided slightly better 

protection than the Clark G-3 on the Wright 

Field centrifuge. Unfortunately, the L-12 

needed higher pressure than was available 

on combat aircraft of the era, so it was never 

ordered into production. The capstans, on the 

other hand, would reappear on the first Henry 

partial-pressure suit.168

In the meantime, David Clark’s experimental 

seamstress, Julia Greene, left Worcester to 

follow her husband to Burbank, CA, where 

he had recently gotten a job with Lockheed. 

This move would prove fortuitous a little later 

in the story, when Greene went to work for 

Henry while he developed his partial-pressure 

suit. Back in Worcester, Alma Charland took 

over the seamstress duties and, being more 

experienced at making patterns, redesigned 

the Z-1 suit to better integrate the shin pockets. The Navy ordered the modified suit into 

quantity production as the Z-2.169

Despite the laboratory success of the Z-2 suit, 

pilots still did not like it; many preferred 

blacking out to wearing it. “Pilots are just 

that way,” Wood said. “They don’t think 

they need anything.”170 But the pilots had a 

point. On the ground, the suit was hot and 

uncomfortable, and crew rooms without 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

105

air conditioning felt like saunas in tropical 

climates. In combat, the suit could actually 

be painful. During high-G maneuvers of 

long duration, the pneumatic bladders could 

stay inflated for up to a minute and feel like 

tourniquets. The suit could cut off blood 

circulation to the legs, which would ache 

with the pain of ischemia like that of a heart 

This is the David Clark Company version of the Z-2 G-suit. 

Note the zippered pockets on the shins, chest, and sleeve. 

Sometimes it seemed as if the location and shape of the pockets were as important as the acceleration protection provided 

by the bladders hidden inside the suit.

Courtesy of the David Clark Company, Inc.

attack. If the abdominal bladder inflated too 

quickly, it gave not the usual hugging feeling 

but something like a punch in the stomach.

Although a clinical success, G-suits were 

proving to be an operational failure.

CUTAWAY SUITS

Up to this point, all G-suits, whether 

designed by Berger Brothers or David Clark, 

had been high-waist trousers or coveralls. 

However, the reluctance of fighter pilots to 

use the suits, mostly due to discomfort, was 

worrisome to the researchers. In response, 

George Maison at Wright Field suggested 

developing a “cutaway” version of the suit 

that a pilot could wear over whatever clothing 

was appropriate (i.e., heavy uniforms in cold 

climates and lighter uniforms in the tropics). 

It was largely the same path taken by Wilbur 

Franks in Canada. This resulted in the G-3 

suit, a cutaway version of the G-2 that looked 

like a set of trousers in which the front of 

the knees, crotch, and buttock area had been 

cutaway. There was just enough material to 

keep the five bladders in the abdomen, thighs, 

and calves in their proper positions. The suit 

came in four standard sizes and used lace 

adjustments for fitting. The David Clark suit 

weighed 2.25 pounds and the Berger Brothers 

suit was about a half pound heavier due to 

its rubber bladders. The G-3 used the same 

airplane-mounted equipment as the G-2 and 

was operationally interchangeable.171

During testing in the Mayo centrifuge, 12 subjects made 320 runs and researchers used visual 

symptoms as a subjective measurement and the 

blood content of the ear and ear pulse as objective measurements. The centrifuge runs lasted 

15 seconds with a maximum acceleration of 

6-G attained at a rate of 2-G per second. The 

Army conducted similar tests at Wright Field 

and the Navy in Philadelphia. All of the tests 

confirmed the new Berger Brothers and David 

Clark cutaway suits provided adequate protection, although somewhat less than the earlier 

coverall type.172 The Army evaluated both 

company’s suits at Eglin Field in June 1944 

and determined that the Clark suit was superior to that from Berger Brothers. The AAF 

Proving Ground Command recommended 

that the Berger Brothers suit be discontinued 

and all future suits be procured from David 

Clark Company.173

Beginning February 8, 1944, the Army Air 

Technical Services Command (ATSC) sponsored a set of conferences to standardize 

G-suits and their supporting equipment as 

part of classified Project MX-389.174 Darwin 

Berger, Spencer Berger, David Clark, Fred 

Moller, and Capt. George A. Hallenbeck 

from the ATSC attended all of the conferences, with other attendees as required.175

Perhaps the most significant agreement to 

come out of the conferences was to standardize the design for the G-3 cutaway suit. On 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

106

A major advance in G-suits came with the advent of a 

“cutaway” suit. This allowed pilots to wear the G-suit over 

whatever clothing was appropriate for the conditions they 

were operating in, such as heavy uniforms in cold climates 

or lightweight cotton in the tropics. The cutaway contained 

just enough material to support the five bladders in the abdomen, thighs, and calves. This also reduced the weight of the 

suit to just 2.25 pounds. The pilots still did not like the suit, 

but they began wearing it since data showed it significantly 

increased their kill rate.

Courtesy of the David Clark Company, Inc.

February 10–11, Moller and Doc Versoy from 

Berger Brothers and David Clark and John 

Chisholm from the David Clark Company 

drew up patterns for the standardized G-3 

suit using an interchangeable bladder system. 

One of the major issues was that the Berger 

Brothers preferred bladders made of rubber or synthetic rubber, while David Clark 

used Vinylite-coated nylon fabric. In the 

end, everybody agreed that Berger Brothers 

would continue to use rubber bladders and 

David Clark would use coated nylon fabric 

but that each company would use the same 

design, making the bladders interchangeable. 

Somewhat later, the Army directed both companies to switch to neoprene bladders that 

were even more durable and somewhat lighter.

Things moved much quicker in 1944, and 

Berger Brothers put the new suit into production on February 25, and David Clark followed on April 15. Munsingwear and several 

other manufacturers also produced the suits. 

By the end of 1944, more than 4,100 G-3 

suits were delivered to the Eighth, Ninth, and 

Twelfth Air Forces, and in November 1944 

the Army officially accepted the G-suit as 

standard equipment and began issuing one to 

every fighter pilot.176

The G-3 suit became operational during 

the fall of 1944, and data soon showed that 

blackouts and grayouts were happening much 

less frequently to pilots who wore the suit. 

None of the safety issues won over pilots but 

performance data finally did. A P-51 Mustang 

fighter group of the Eighth Air Force reported 

that pilots wearing anti-G suits shot down 

67 enemy aircraft per 1,000 operational hours, 

compared with only 33 kills for other pilots. 

A doubling of the kill rate was persuasive.177

Based on comments from the combat zones, 

a slightly improved Type G-3A suit was soon 

developed to further improve comfort. The 

outer suit used a sage-green, basket-weave 

nylon cloth, and the inside areas around the 

bladders used an oxford-weave cloth because it 

tended to slip less around seams. The new suit 

provided 1.1-G of protection on the Wright 

Field centrifuge and 1.2-G on the Mayo Clinic 

machine. The suit came in four sizes: small 

short, small long, large short, and large long, 

and laces over the calves, thighs, and flanks 

provided custom fitting. Surprisingly, the 

G-3A weighed almost a pound more than the 

initial Clark G-3. Late in its production, the 

G-3A came with a device that allowed the suit 

to be inflated by mouth and used as a life vest 

if the pilot was forced into the water.178

After Germany fell, the United States cutback 

many defense contracts, but the need for 

G-suits kept both Berger Brothers and David 

Clark busy. When V–J Day arrived, the military cancelled many contracts entirely, including the G-suit contract with Berger Brothers. 

The one with David Clark Company, however, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

107

Pilots universally disliked all of the early G-suits but began 

to change their minds once the statistics began showing their 

combat performance, as measured in “kills” of enemy aircraft, 

improved while wearing the suits. In particular, a P-51 

Mustang fighter group of the Eighth Air Force reported that 

pilots wearing anti-G suits shot down 67 enemy aircraft per 

1,000 operational hours, compared with only 33 kills for 

other pilots.

National Museum of the United States Air Force Collection

continued, although the company again began 

manufacturing undergarments for the civilian 

market (they were the “Sears Best” brassiere 

manufacturer through the 1950s). Showing 

how the conduct of business differed during 

the war years, when the end of 1945 came, 

the David Clark Company realized they had 

made better than a 10 percent profit on a Navy 

G-suit contract. This was mostly because they 

had bid the per-suit cost before production 

ramped up and the true cost of making the 

suit was known. The company cut a check 

for $88,000 and returned the excess profits 

to the Navy, which, somewhat bewilderingly, 

accepted it.179

Even before V–J Day, there were some major 

changes in work for G-suits, although neither 

David Clark nor Fred Moller knew what they 

were for. For instance, George Maison asked 

David Clark to modify the pressurization 

valve to operate from much higher pressure, 

although details of its intended application 

were not immediately forthcoming. In fact, 

the modification was necessary to adapt 

the valve to use bleed air from the turbojet 

engines under development at GE.180

In due course, the military gave David Clark 

permission to visit Muroc Army Air Field in 

California and witness test flights of both the 

Bell P-59A Airacomet and Lockheed P-80 

Shooting Star. At the time, both airplanes were 

flying without the benefits of a G-suit. Richard 

Cornelius modified his valve to accept air from 

the highest stage of the compressor side of the 

General Electric I-16 and I-40 turbojets (later 

produced as the J31 and J33).181

At the request of the Navy, David Clark also 

developed a set of full coveralls that contained 

bladders similar to the G-3. Naval Aviators 

preferred the resulting Z-3 suit since they wore 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

108

The Lockheed P-80 program drove major changes to the way 

air was obtained to operate G-suits. The P-80 was the first 

operational jet fighter in the United States and formed the 

basis of the successful T-33 trainer that saw service for decades 

after World War II. Somehow, it seems that Lockheed was 

intimately involved with much of the evolution of G-suits 

and pressure suits.

National Museum of the United States Air Force Collection

it instead of a normal flight suit, eliminating 

one piece of clothing; it was also somewhat 

cooler since only a single layer of cloth covered 

the belly and legs. These were step-through 

coveralls made of lightweight, inelastic, porous 

rayon cloth fitted with one abdominal and 

two leg zippers. At the David Clark Company, 

Joseph Ruseckas patterned the suit after the 

standard summer flight suit, and it came in 

nine sizes without lace adjustments. While he 

was developing the patterns, Ruseckas integrated the parachute harness into the garment. 

The Army bought a limited number of these 

suits under the G-4 designation.182

Although the G-3 cutaway and G-4 coverall 

suits used similar bladder systems, there were 

some important differences. The bladders in 

the G-3 had a volume of 12.1 liters, while the 

G-4 used only 9.7 liters, primarily by reducing the size of the abdominal bladder. Under 

identical conditions, this, along with eliminating the leg lace adjustments, had the effect of 

reducing protection from 1.9-G for the G-3A 

to 1.5-G for the G-4. These changes made the 

G-4 more comfortable for the pilots, but in 

1947, David Clark introduced the G-4A that 

used a larger abdominal bladder and provided 

1.9-G of protection.183 Based on service trials 

on 25 fighter pilots during 1948 using both 

the G-3A and G-4A, the USAF determined 

the G-4A was more effective and more comfortable. The USAF subsequently adopted 

the G-4A as its standard G-suit for the next 

several decades.184

By early 1948, the USAF was having second 

thoughts about relying completely on the 

David Clark Company for its G-suits, not 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

109

because of any failing with the company, 

but because of competitive “sole source” 

contracting concerns. Two other companies 

expressed interest: the Drybak Outdoor 

Clothing Company of Binghamton, NY, 

and Warner Brothers of Bridgeport, CT. 

The USAF asked David Clark to assist both 

companies in making prototype suits. When 

the USAF announced the winners of the 

first competitive procurement, David Clark 

and Drybak shared the contracts. Eventually, 

David Clark Company stopped producing 

G-suits since there were fewer development 

opportunities, concentrating instead on the 

development of pressure suits.185

Given the head start that Wilbur Franks and 

the Canadians had on developing G-suits, 

it came as a crushing blow when the RCAF 

decided in 1948 to purchase suits from David 

Clark Company. When Franks arrived in 

Worcester, David Clark showed them a new 

suit sewn by Joe Ruseckas. Franks asked 

for some changes, including a larger belly 

bladder, and took the suit back to Toronto 

for testing on the Canadian centrifuge. The 

RCAF liaison at the Canadian Embassy in 

Washington soon called David Clark and 

ordered 50 suits for immediate delivery 

and indicated an additional order would be 

forthcoming for an additional 250 suits (this 

order eventually got sidetracked, through the 

Mutual Defense Assistance Program (MDAP) 

scheme, to another supplier). The RCAF was 

getting ready to deploy to Korea and needed 

the additional protection for its pilots.186

POSTWAR SUITS

Shortly after the end of World War II, the 

United States essentially halted attempts to 

develop G-suits that were more effective than 

the standard G-4A because the aircraft of the 

era did not appear to need a better garment. 

Nevertheless, minor modifications resulted in 

the USAF and Navy using a variety of G-suits 

through the end of the 20th century. 

The CSU-12/P coverall developed for the 

USAF used pneumatic bladders located at the 

abdomen, right and left thigh, and right and 

left calf. The bladder casings were fabricated of 

chloroprene-coated nylon and the outer cover 

of interwoven nylon and cotton. Laces at the 

waist, thighs, and calves, covered by a Velcro 

flap, allowed individual adjustment.187

The CSU-13/P was a cutaway G-suit developed for the USAF that provided essentially 

the same protection as the CSU-12/P coverall. Bladders were located at the abdomen, left 

and right thigh, and left and right calf. The 

bladder casings were fabricated of polyurethane-coated nylon taffeta and the outer cover 

of interwoven nylon and cotton. Laces at the 

waist, thighs, and calves, covered by a Velcro 

flap, allowed individual adjustment. The 

CSU-13A/P was a slightly revised version that 

used an outer cover of 95 percent Nomex and 

5 percent Kevlar cloth.188

The CSU-15/P cutaway G-suit developed for 

the Navy used pneumatic bladders located at 

the abdomen, left and right thigh, and left 

and right calf. This suit differed from contemporary USAF suits by having different sized 

bladders, additional lacing adjustments, and 

a longer disconnect hose.189 A slightly revised 

version was designated CSU-15A/P. The official description of the CSU-15/P cutaway suit 

did not differ much from the wartime G-3A: 

The CSU-15/P anti-G garment consists of a fire-resistant Aramid cloth 

outer shell, which houses a bladder. It 

is cut away at the buttocks, groin, and 

knees. The outer shell has waist and leg 

entrance slide fasteners, six adjustment 

lacing areas with lacing covers, and two 

easily detached leg pockets with slide 

fastener closures. The bladder system is 

constructed of polyurethane-coated nylon 

cloth and covers the abdomen, thighs, 

and calves. The bladder system is fitted 

with a hose for connecting directly to 

the aircraft anti-G system. This anti-G 

garment is available in six sizes.190

On February 25, 1982, the Air Force and 

Navy met at the Naval Air Development 

Center in Warminster, PA, to discuss standardizing on a single G-suit design to replace 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

110

the CSU-13/P and CSU-15/P, respectively. 

Although the construction and placement of 

the bladders differed somewhat in the two 

suits, the major differences were external. For 

instance, the CSU-13/P leg closure zippers 

closed in an upward direction, while the CSU15/P used quick-release closures that separated 

downward. The pocket configuration differed, 

as did the air supply attachment hose. The Air 

Force had a large extra-long size that the Navy 

did not, while the Navy had a small, short size 

for women that the Air Force did not. The Air 

Force rated the service life of the CSU-13/P at 

12 months, but the Navy used the CSU-15/P 

for 18 months.191

During flight evaluations, pilots generally 

expressed a preference for the suit they 

were used to but felt that either suit was 

satisfactory. Based on the results of the tests, 

the Department of Defense selected the CSU13/P as the common G-suit. The specific triservice model became the CSU-13B/P. This 

cutaway suit used an Aramid cloth outer shell 

that contained polyurethane-coated nylon 

abdomen, thigh, and calf bladders. The outer 

shell had waist and leg entrance slide fasteners, 

six lace adjustments with Velcro covers, and 

two detachable leg pockets with slide fastener 

closures. The suit came in seven sizes: small 

regular, small long, medium regular, medium 

long, large regular, large long, and large extralong. The suit was fabricated by a variety of 

manufacturers, including Aerotech Industry 

Corporation, Life Support International, Inc., 

and Mustang Survival (Mustang Sportswear, 

Ltd.). The CSU-13B/P replaced all earlier Air 

Force and Navy G-suits as they reached the 

end of their service lives.192 Pilots commonly 

referred to the CSU-13B/P (and many other 

G-suits) as “speed jeans.” 

Although the CSU-13B/P was the standardized suit, several other G-suits were also used 

by the United States. For instance, the F-16/

PBG was developed by the Air Force Flight 

Test Center (AFFTC) at Edwards AFB specifically for the F-16 Combined Test Force. The 

F-16/PBG featured the same G-suit bladder 

coverage as the standard CSU-13B/P but 

incorporated inflatable chest bladders into the 

upper portion of the ensemble to assist with 

pressure breathing above 5-G. The suit used 

laces on the legs and torso to provide a snug 

fit. Below 5-G, the G-suit and chest bladders 

functioned independently; above 5-G, the 

G-valve sent a proportionate pneumatic signal 

to activate the oxygen regulator to proportionately increase breathing-gas output to the 

chest bladders and the oxygen mask.193

As a possible replacement for the F-16/PBG, 

from June 21 through August 24, 1989, the 

F-16 CTF evaluated the Swedish Tactical 

Flight Combat Suit (TFCS). The TFCS was 

an integrated life support ensemble designed to 

provide protection from high-G, cold-water 

immersion, and temperature stress. 

Components of the ensemble included a 

lightweight helmet: low-profile, high-pressure 

oxygen mask: an integrated full-coverage 

anti-G and immersion suit: and a specialized 

pressure/survival vest. The suit was tested 

in a slightly modified General Dynamics 

F-16B (81-0816) at Edwards. The evaluators 

felt the TFCS provided better protection 

than the F-16/PBG and offered a significant 

improvement over the standard-issue CSU13B/P G-suit. However, the TFCS was bulkier 

and more restrictive of movement than either 

American ensemble. Despite the TFCS vapor 

barrier, it was no cooler in the hot Edwards 

environment than the F-16/PBG. The TFCS 

helmet offered improved fields of view and 

greater noise attenuation. Notwithstanding the 

advantages offered by the Swedish garment, 

the USAF did not procure it.194

TLSS AND COMBAT EDGE

Officially, what came next are called “Anti-G 

Suits,” but, in reality, they are closer to partialpressure suits. To increase pilot performance 

under acceleration, modern G-suits use 

pressure-breathing masks and counter-pressure 

vests in concert with lower-body G-suits. 

These suits also provide limited altitude protection up to 50,000 or 60,000 feet, although 

the lack of arm and hand protection limits 

their use at high altitudes to a few minutes 

(truly a get-me-down capability). A brief 

description of the suits and their development 
111

The McDonnell Douglas F-15 Eagle was the first of a new 

generation of highly maneuverable aircraft that drove the 

development of improved acceleration protection. These 

aircraft were capable of sustained +9-Gz maneuvers, well 

beyond the capabilities of the then-current, wartime-derived 

G-suits. In addition, the F-15 had a thrust-to-weight ratio 

of greater than 1:1, making radical vertical maneuvering 

feasible for the first time. 

U.S. Air Force

is presented here instead of in the partialpressure suit chapter for consistency with 

what the Government calls the ensembles.

During the early 1970s, Dr. Sidney Leverett 

and his colleagues at the USAF School of 

Aerospace Medicine recognized the need for 

better G-protection to accompany the very 

maneuverable McDonnell Douglas F-15 Eagle 

and General Dynamics F-16 Fighting Falcon. 

These aircraft were capable of sustained 9-Gz 

maneuvers, well beyond the capabilities of the 

then-current, wartime-derived G-suits.195 In 

response, the Air Force established the Tactical 

Life Support System (TLSS) program. This 

effort had a wide range of research objectives 

that included “NBC” (nuclear, biological, 

chemical) protection, advanced anti-G protec-

tion, moderate high-altitude (60,000 feet) 

protection, thermal-flash-protection goggles, 

aircrew cooling (via a liquid-cooling gar-

ment), and on-board oxygen generation via 

molecular-sieve apparatus (onboard oxygen 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

112

generation system, or OBOGS). Meeting all 

of the requirements involved the development 

of several new pieces of equipment, including 

a new breathing regulator that could interface 

with the OBOGS and a new type of G-valve to 

operate the G-suit and counter-pressure vest.196

Instead of a competitive development effort, 

the Government formed a team that included 

various USAF laboratories, the Canadian 

Defence and Civil Institute of Environmental 

Medicine (DCIEM), Boeing, and Gentex. 

As with most ambitious programs, TLSS ran 

behind schedule and over budget, and it eventually dropped some of its original objectives.

The DCIEM was responsible for design of 

the TLSS G-suit and constructed a garment 

that included a lower-body G-suit and a 

counter-pressure vest to aid with pressure 

breathing. The suit featured full NBC and 

thermal flash-protection goggles. Canada had 

earlier identified the need for suitable highaltitude protection for aircrews of the new 

high performance fighter it was planning to 

acquire. However, when that aircraft turned 

out to be the McDonnell Douglas CF-18 

Hornet, which was limited to altitudes around 

50,000 feet, the need for the suit largely went 

away. Nevertheless, Canada continued to participate in the TLSS program until the end.

The TLSS was flight-tested at Edwards during 

1986–87 using an F-15B and F-16B with 

generally positive results. Four pilots tested 

the fully integrated TLSS prototype system 

(including OBOGS) in the front seat of the 

F-15B during 26 flights that included highaltitude, air-to-air, and air-to-ground roles. 

A simplified system that used a modified 

CRU-73 breathing oxygen regulator and 

the existing G-valve was tested in the 

back seat of an F-16B by 4 pilots during 

24 flights in the air-to-air mode. In addition, 

the suit successfully survived an explosive 

decompression at 60,000 feet in the Brooks 

AFB altitude chamber. Despite its seeming 

success, the Air Force and Congress ultimately deemed TLSS too expensive to 

produce in large numbers.

However, the relative success of the simplified 

system tested in the F-16B resulted in the Air 

Force redirecting the program during 1988 

toward improving G-protection and dropping 

many of the other original goals. In part, 

this was the result of a significant increase 

in gravity-induced loss of consciousness 

(G-LOC) accidents in the F-16.

The USAF School of Aerospace Medicine 

undertook an extensive series of centrifuge 

studies with several combinations of 

components from the TLSS and other sources 

to define a workable combination that could 

be fielded quickly at a reasonable cost. Five 

different ensembles were ultimately selected 

for further testing. Ensemble I used the TLSS 

fully integrated pressure-vest/torso garment 

(upper-pressure garment, or UPG), TLSS 

extended-coverage G-suit (lower-pressure 

garment, LPG), and a modified CRU-73 

regulator. Ensemble II included the TLSS 

component pressure vest/torso garment, 

standard CSU-13B/P G-suit, and modified 

CRU-73 regulator. The component pressure 

vest did not provide complete coverage of the 

torso like the fully integrated pressure vest. 

Ensemble III used an extended pressure-vest/

torso garment, CSU-13B/P G-suit, and a 

modified CRU-73 regulator. The extended 

pressure vest provided more coverage than the 

component pressure vest, but not as much as 

the fully integrated pressure vest. Ensemble 

IV featured the extended pressure vest/

torso garment, a full-coverage G-suit, and a 

modified CRU-73 regulator. The full coverage 

G-suit used bladders that completely covered 

the thighs and calves instead of the separate 

bladders in the CSU-13B/P that only applied 

counter-pressure to the sides of the limb. 

Ensemble V used the extended pressure vest/

torso garment, full-coverage G-suit, and an 

experimental (NGL) pressure regulator from 

the United Kingdom that provided the same 

pressures as the CRU-73 at lower breathing 

resistance. All of the ensembles used the TLSS 

helmet and oxygen mask.

Based on the results of tests on the Brooks 

human centrifuge, Ensemble III seemed 

to offer the best compromise between 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

113

protection and comfort. This was also one 

of the least expensive options to implement. 

This configuration became the basis for the 

Combined Advanced Technology Enhanced 

Design G-Ensemble, which, became better known as Combat Edge. The TLSS 

helmet was replaced with the already fielded 

lightweight HGU-55/P. However, the tests 

conclusively demonstrated the full-coverage 

G-suits significantly increased acceleration 

protection, so their development was continued as the Advanced Technology Anti-G 

Suit (ATAGS).197 Various configurations of 

extended coverage G-trousers were designed 

and tested, and some of the designs provided almost 100-percent coverage and even 

included booties to cover the feet.198

For all intents, Combat Edge is a description 

of pressure breathing, and the components 

of Combat Edge act in unison to sense and 

respond to high-G conditions. The G-valve 

sends a signal to the oxygen regulator to 

increase mask pressure up to 1.2 psi above 

ambient. This same pressure is routed to the 

occipital bladder in the back of the helmet, 

causing it to inflate and push the pilot’s face 

into the oxygen mask. This same pressure 

is also sent to the counter-pressure vest to 

balance the breathing pressure supplied to the 

lungs. Ultimately, Combat Edge maintains 

pressure in the pilot’s chest cavity to help the 

heart pump blood to the eyes and brain while 

inhibiting the downward blood flow.199

Physiologists differentiate between pressure 

breathing for G (PBG) and pressure breathing 

for altitude (PBA) although the differences 

are so subtle as to be lost on laymen. In the 

PBG mode, the same pressure that is applied 

to the vest bladders is supplied to the pilot’s 

respiratory system through the oxygen mask. 

Combat Edge obtains two beneficial effects 

from this action. The most obvious benefit is 

that the pilot can breathe during PBG, but 

in addition, since the system is squeezing the 

pilot’s chest from the inside as well as the 

outside, it denies even more volume for blood 

pooling and more blood is pushed toward 

the head. 

The pressure level of the Combat Edge

PBG breathing air supply is controlled by 

the breathing air regulator, which in turn, 

is controlled by the G-valve. An important 

system feature is the interlock between 

the trousers and vest that is created by this 

method of control. The system design ensures 

that the G-trousers are fully pressurized and 

inflated before the counter-pressure vest 

can begin to fill and apply pressure. If this 

interlock did not exist, and the counterpressure vest filled first, the blood from the 

legs and abdomen would be trapped and 

could not rise toward the pilot’s head. The 

G-trouser pressure level is several times 

higher than the PBG pressure level. The 

output pressure of the PBG regulator varies 

in response to the output pressure of the 

G-valve; therefore, the PBG pressure level also 

varies as a ramp function in response to higher 

acceleration levels.200

During the early 1980s, the L-1 anti-G 

straining maneuver replaced the original 

M-1 developed by the Mayo Clinic during 

World War II. The L-1 maneuver combines 

a regular, 3-second strain (Valsalva) against a 

closed glottis, interrupted with rapid exhalation and inhalation while tensing of all major 

muscles of the abdomen, arms, and legs. 

Properly executed, it provides an average pilot 

approximately 1.5-G protection. This is about 

the same as the standard G-suit, so combined 

the suit and straining maneuver provide 

about 3-G protection. The M-1 maneuver 

was essentially the same but against a partially 

open glottis, causing the pilot to audibly grunt 

during the strain, resulting in lower intrathoracic pressures. The Navy teaches a slight 

variation of the L-1 called the Hook Maneuver in which the pilots initiate the strain phase 

by saying, “hook” as they begin to strain. This 

helps ensure a completely closed glottis.201 In 

either case, the signal to commence straining 

is the beginning inflation of the bladders, felt 

first in the G-suit.

While Combat Edge does not replace the 

straining maneuver, it significantly reduces 

the effort required to execute it. A common 

misconception is that fighter pilots tend 

to make long sweeping turns that produce 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

114

The CSU-20/P is similar to the CSU-13B/P 

with a 40-percent increase in leg- and abdomen-bladder coverage. It has a flame-resistant 

cloth outer shell with waist and inner-leg slide 

fasteners, adjustment lacing with covers, and 

leg pockets with slide-fastener closures. The 

CSU-21/P vest has a flame-resistant cloth 

outer shell with a front slide-fastener closure 

for easy donning and doffing and laces to 

allow sufficient adjustment for correct fit.206

Somewhat before the development of 

Combat Edge, McDonnell Douglas 

undertook a program called Atlantis Warrior, 

led by Dr. D. Lambert, which was conceived 

around a hydrostatic suit containing 6 liters 

of water. It was conceptually similar to what 

Bill Franks fabricated during World War II. A 

prototype was tested on a human centrifuge, 

where it reportedly performed well, and where 

it demonstrated the ability for the pilot to 

talk under +10-Gz acceleration loads for up 

to 3 minutes and maintain consciousness at 

+12-Gz.207 The suit underwent comparative 

human prolonged high-G exposure testing 

during 1996 at Wright-Patterson AFB. These 

tests showed a higher number of tolerated 

5-9-Gz peaks compared to the other suits, 

and subjects did not suffer any documented 

episodes of G-LOC.208 Despite its clinical 

success, Atlantis Warrior was not produced.

Interestingly, the German Luftwaffe finally 

fielded a hydrostatic G-suit, 60 years after 

The initial USAF Combat Edge ensemble 

consisted of the CSU-17/P counter-pressure 

vest, CSU-13B/P G-suit, HGU-55/P helmet 

with an occipital bladder, and MBU-20/P 

oxygen mask. The flight-test community 

evaluated the first prototypes at Edwards 

in 1988, and formal testing took place in 

1990 using F-15s and F-16s. Operational 

test and evaluation of the ensemble was 

completed in 1991, and all F-15 and 

F-16 aircraft were modified, mostly with 

new G-valves, to accept the equipment by 

mid-1995. New production aircraft after 

that date have the equipment installed at 

the factory.

The Navy was not completely happy with 

the Combat Edge ensemble. Instead of the 

CSU-15B/P G-suit, the Navy selected the 

Canadian-developed Sustained Tolerance 

for Increased G extended-coverage G-trouser. 

The Navy Combat Edge ensemble is designated A/P22P-16 and provides enhanced 

acceleration protection between +4- and 

+9-Gz to an altitude of 50,000 feet. Below 

+4-G, the ensemble provides the same 

level of protection as the CSU-15B/P. The 

Navy uses Combat Edge only in the 

F/A-18 fighter. The ensemble consists of 

the CSU-20/P cutaway anti-G garment, 

CSU-21/P counter-pressure vest with a 

chest-mounted CRU-103/P G-compensated 

oxygen breathing regulator, HGU-68/P 

helmet, and MBU-24/P oxygen mask.205

medium-to-high acceleration levels that are 

maintained for a relatively long time. In fact, 

this is seldom the case. Air combat maneuvering (ACM) is a constantly changing acceleration environment, often consisting of a zigzag 

pattern that generates anywhere between 

+5-Gz and +9-Gz on each alteration. Except 

for the straining action, Combat Edge functions automatically. The bladders sequentially 

inflate and deflate, the mask tightens and loosens, and the pilot is allowed to concentrate on 

flying the airplane. At the end of a mission, 

the pilot who has flown with Combat Edge is 

considerably less fatigued than one flying the 

same mission in a conventional G-suit.202

Despite its improved acceleration protection, the Combat Edge counter-pressure vest 

has a significant drawback: it is hot to wear. 

The original TLSS-integrated flight suit used 

a liquid-cooling system composed of tubing threaded inside the bladder layer. This 

liquid-cooling system was not carried forward 

as part of Combat Edge because it was not 

logistically supportable, leaving the Combat 

Edge vest somewhat uncomfortable in some 

climates. Nevertheless, liquid-cooling systems 

continue to have supporters, and the Eurofighter Typhoon uses one.203 Recently, the Air 

Force authorized use of the Combat Edge

system without the counter-pressure vest, the 

justification being enough flight-hours have 

been accumulated to show that the wearer 

would not be in danger.204
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

115

it initially developed, and rejected, the concept. The Libelle G-Multiplus, developed by 

Autoflug Libelle GmbH (a joint venture of 

Life Support Systems AG of Switzerland and 

Autoflug GmbH of Germany), is a full-body 

G-suit that uses hydrostatic rather than pneumatic pressure. The suit looks much like what 

Harold Lamport at Yale and Helen Lester and 

David C. Spooner at General Electric developed in 1943, with the primary difference 

being the fact that the capstan tubes are fluid 

filled instead of air filled.

“Libelle” is German for “dragonfly,” because 

the suit is based on the same principles that 

protect a dragonfly from the 30-G accelerations the insect generates in flight. The suit 

uses 0.3 gallons of liquid to exert counterpressure during acceleration. When acceleration forces push blood toward the lower part 

of the body, it also pushes the liquid inside 

the suit in the same direction, providing a 

counter-pressure that is automatically adjusted 

by the G-load itself. The suit uses fluid-filled 

channels traversing the arms, torso, and legs 

to tension its snug-fitting fabric. The suit is an 

autonomous, stand-alone system that does not 

require air or power from the aircraft.209

The suit was tested on the centrifuge at 

the German Air Force Institute of Aviation 

Medicine in Königsbrück and in more than 

200 flights in Pilatus PC-7 turboprop trainers 

and a Learjet belonging to the Swiss Air 

Force. With this ensemble, pilots were able 

to withstand accelerations between –0.9-Gz 

and +10.4-Gz and at a maximum onset of 

+5-G per second with no apparent decrease 

in situational awareness.210 During 1998, 

the Swiss and German air forces evaluated 

the suit in a direct comparison between the 

Libelle suit and the standard CSU-13B/P 

pneumatic suit using 10 subjects (8 fighter 

pilots, 1 M.D., and 1 civilian pilot). At that 

point, the Libelle consisted of a seat cushion 

that provided G-proportional pretensioning 

of the suit to allow for optimal efficacy of 

the hydrostatic capstan-like principle. The 

suit performed reliably and did not cause 

any G-LOC in a passive-acceleration profile 

and in simulated air-combat maneuvering. 

The Libelle system achieved a relaxed 

G-tolerance of +7.1-Gz compared to +6.7-Gz 

for the CSU-13B/P—a statistically irrelevant 

difference. Problems with the suit primarily 

were the very tight fit and the need for a 

different straining maneuver.211

Combat Edge pilots need to perform a 

straining maneuver as their contribution 

to the successful system performance. 

The signal to commence straining is the 

beginning inflation of the bladders, felt first 

in the G-trousers. Combat Edge-trained 

aircrew who have flown the “automatic” 

Libelle suits note that this physical signal is 

missing because hydrostatic operation does 

not offer the sensation of the G-suit inflating 

at the onset of acceleration. Some of the 

subjects reported they had to be much more 

conscious of the maneuvering of the aircraft 

to add their straining effort at the proper 

moment. Researchers determined the training 

requirements for optimum use of the system 

were almost the exact opposite to those of 

Combat Edge. Instead of straining (which 

will cause at least an interruption in normal 

breathing), the trainee for the Libelle system is 

encouraged to breathe as normally as possible. 

This promotes a greater ability to speak 

during the high-G maneuver. If the Libelle 

system were to be adopted, the Libelle training 

regimen would also have to be put in place.

Beginning in March 2000, the Libelle was 

evaluated by the USAF on centrifuges at 

Holloman AFB and Brooks AFB and during 

flight demonstrations at the USAF Test Pilot 

School at Edwards AFB. The evaluation did 

not exceed +9-Gz in either the centrifuge or 

flight tests. In general, the evaluation team 

had a favorable opinion of the Libelle, which 

offered certain advantages over the Combat 

Edge suit.212 In the end however, the USAF 

did not pursue the Libelle system. Dr. Ola 

Eiken and his team also evaluated the suit 

on the human centrifuge in Sweden in 2002. 

They studied three pilots in the Saab JAS-39 

Gripen extended-coverage G-suit and compared it to the tolerance afforded by use of the 

Libelle suit. The results showed a G-tolerance 

of +6.3-Gz with the Libelle suit and +9.0-Gz 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

116

with the standard pneumatic suit, a result 

seemingly favoring the older technology.213

Nevertheless, on January 31, 2005, the Libelle 

G-Multiplus became operational in Typhoons 

from Jagdgeschwader 73 of the German Air 

Force at Laage Air Base.

ATAGS AND THE F-22

As the TLSS program morphed into Combat 

Edge, human centrifuge tests continued 

to show that full-coverage G-suits offered 

significantly increased acceleration protection, 

so the Air Force continued to develop the 

garments as the Advanced Technology Anti-G 

Suit (ATAGS).214 Various configurations of 

extended coverage G-trousers were designed 

and tested. Some of the designs provided 

almost 100-percent coverage and even 

included booties to cover the feet.215

The final configuration of the G-suit was designated CSU-23/P but is generally still called 

ATAGS. As a stand-alone garment, ATAGS 

provides a 60-percent increase in aircrew 

endurance. Combined with Combat Edge, 

it increases aircrew endurance by 350 percent 

over the standard G-suit. Unlike other G-suits, 

ATAGS completely envelops the legs and buttocks and rides lower on the torso so that it 

does not push against the chest.216

Oddly, unlike all previous G-suits for the 

past 50 years, the air connections for the 

CSU-23/P are on the right side of the suit, 

explaining why it is only compatible with the 

Lockheed Martin F-22 Raptor. On June 30, 

2008, the Air Force awarded the latest contract for 150 ATAGS CSU-23/P G-trousers to 

Vinyl Technology, Inc. of Monrovia, CA, for 

$741,501, or approximately $4,943 each.217 A 

similar ATAGS suit, designated CSU-22/P, has 

interfaces on the left side that are compatible 

with the F-15, F-16, and F/A-18.218

Having a unique G-suit for the F-22 posed 

a variety of logistical problems for the Air 

Force, so the Air Combat Command asked 

the Armstrong Laboratory to evaluate if the 

CSU-23/P could be replaced by the standard 

CSU-15B/P from Combat Edge. Of course, 

the F-22 would still have its interface connections on the right side of the cockpit, meaning either the CSU-13B/P would need to be 

modified (negating the point of the exercise) 

or some method would need to be found of 

connecting a left-handed G-suit to a righthanded airplane.219

Since there are no two-seat F-22s, the Air 

Force decided to use a two-seat F-15B for the 

evaluations. This presented a problem since 

the CSU-13B/P is configured to work correctly 

in an F-15. The solution was to fabricate nine 

CSU-13B/P suits with the inlet hose moved 

to the right-hand side. A hose was developed 

that routed the air across the ejection seat to 

interface the nonstandard suits with standard 

left-hand connections. Three test conditions 

were evaluated, one using a standard left-hand 

CSU-13B/P suit, one using the modified righthand CSU-15B/P suit, and the last using the 

CSU-23/P suit. For each of these, the G-suit 

was inflated according to the standard aircraft 

schedule. Pressure breathing began at +4Gz, 

with a linear increase in pressure of 12 mm 

Hg per G to a maximum of 60 mm Hg at 

+9Gz. The maximum possible time for each 

condition was 90 seconds. Unsurprisingly, the 

researchers decided it did not matter which 

side the G-suit hose connection was on.

The researchers did find, however, that the 

CSU-23/P provided better protection under 

some conditions than the CSU-15B/P. For 

instance, the CSU-23/P demonstrated a lower 

discomfort level and lower heart rate during 

gradual acceleration. The suit also allowed 

the pilot to endure constant acceleration 

for longer periods, and a lower heart rate 

during rapid acceleration. The test subjects 

also tended to rate the CSU-23/P better 

than the CSU-15B/P in overall G-protection 

and fatigue level after G-exposure.220

Instead of joining ATAGS, the Navy initiated a parallel program called the Enhanced 

Anti-G Lower Ensemble (EAGLE) to develop 

an improved G-suit. There were significant 

differences between ATAGS and EAGLE. The 

ATAGS CSU-23/P had a smaller abdominal 

bladder than the standard CSU-13B/P G-suit 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

117

and the leg bladders completely enclosed 

the legs and feet. The EAGLE CSU-20/P 

abdominal bladder was the same size as the 

CSU-13B/P, and the leg bladders completely 

enclosed and pressurized the upper and lower 

legs down to the boot, but the knees and feet 

were unprotected. EAGLE also included a 

CSU-21/P counter-pressure vest, MBU-24/P 

pressure breathing mask (an MBU-20/P with 

Navy communications equipment), and an 

upgraded HGU-68/P helmet with a bladder. The HGU-68/P helmet featured a much 

improved, lightweight, and easily adjusted 

external visor that had been rocket-sled tested 

at the Hurricane Mesa facility to resist ejection 

windblast forces in excess of 600 knots.221

In 1993, the Air Force Armstrong Laboratory 

compared the performance of the ATAGS 

and EAGLE G-trousers. The human centrifuge tests began at +3-Gz for 15 seconds and 

increased to a maximum of +9-Gz until physiological termination criteria were exceeded or 

The retrograde inflation anti-G suit (RIAGS) was a modern 

incarnation of the 1943 progressive arterial occlusion suit 

(PAOS) and featured a set of bladders that progressively 

inflated from the ankles to the abdomen. The goal was 

to develop a G-suit that offered a significant increase 

in protection over the CSU-13B/P G-suit that was in 

widespread service. 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

118

the 15-second limit was reached, whichever 

came first. The tests found that both sets of 

trousers provided better protection than the 

standard CSU-13B/P, although they each had 

disadvantages such as increased heat load and 

reduced mobility. The researchers found that, 

statistically, the ATAGS with pressure socks 

provided better protection than the EAGLE, 

which did not include pressure socks. The 

test subjects also reported less fatigue with 

the ATAGS.222

REDISCOVERING THE PROGRESSIVE 

ARTERIAL OCCLUSION SUIT

David Clark and Earl Wood’s 1943 progressive arterial occlusion suit (PAOS) was briefly 

resurrected in 1989, when Lloyd D. Tripp, Jr., 

and researchers from Systems Research Laboratories and the Crew Systems Directorate of 

the Biodynamics & Biocommunications Division at Wright-Patterson AFB began looking 

for more effective G-suits. According to the 

researchers, “the original PAOS design was resurrected because of the G-induced loss of consciousness problem in USAF aircraft and the 

suit’s apparent improvement in G-protection 

over the standard CSU-13B/P G-suit.”223

The Retrograde Inflation Anti-G suit (RIAGS) 

used a series of bladders that progressively 

inflated from the ankles to the abdomen. 

In addition, two different sets of arms were 

developed: one used arterial occlusion cuffs 

that inflated to 12 psi, and the other used a 

set of capstans and interdigitizing laces that 

inflated to 30 psi.224

Fittingly, the Systems Research Laboratories 

issued a purchase order to the David Clark 

Company for the fabrication of the experimental suit. The effort included fabricating a 

G-suit that could be tested in three configurations: the basic abdomen and leg trousers, 

those with arm and/or leg arterial-occlusion 

cuffs, and any combination of those with a set 

of capstan sleeves. Modified medium-long, 

blue Nomex CWU-27/P flyers coveralls were 

also fabricated for each of these combinations. 

The urethane-coated nylon bladders were 

ultrasonically sealed, resulting in a lighterweight and less bulky suit than had been fabricated in 1943. The basic G-suit consisted of 

bladders located on the legs and abdomen that 

could be inflated to 12 psi. The arm and leg 

cuffs could also operate at 12 psi, while the 5:1 

ratio capstans on the sleeves operated at 30 psi 

to provide 6 psi of skin pressure.225

The suit was tested on the Dynamic Environment Simulator, a 19-foot radius human centrifuge at Wright-Patterson AFB. The results 

showed that most of the subjects complained 

about the arterial occlusion cuffs, reporting 

tingling hands and fingers, decreased dexterity 

of the hands, and in some cases, pain. The use 

of the capstan sleeves provided better protection than the standard CSU-13B/P G-suit, 

The RIAGS leggings contained a set of urethane-coated nylon 

bladders on the legs and abdomen that could be inflated to 

12 psi. Modern fabrication techniques resulted in bladders 

that were considerably less bulky than those used on the 

1943 suit.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 3: Acceleration Protection

119

To cover the RIAGS leggings, David Clark Company 

fabricated a modified set of CWU-27/P flyers coveralls in 

blue Nomex. Although the suit performed well, by the time 

the RIAGS tests were completed, the Armstrong Laboratory 

at Brooks AFB was well along with the development of the 

Advanced Technology Anti-G Suit (ATAGS) and the RIAGS 

concept was dropped.

Courtesy of the David Clark Company, Inc.

but the arterial cuffs provided no meaningful 

increase in protection. When the PAOS suit 

had been tested at the Mayo Clinic in 1943, 

the test durations were very short, and the use 

of arterial cuffs provided a meaningful, shortduration increase in acceleration protection. 

However, the modern tests ran much longer 

and showed the cuff actually decremented 

protection compared to either not having any 

arm protection or to using the capstan sleeves. 

By the time the RIAGS tests were completed, 

the Armstrong Laboratory at Brooks AFB was 

well along with the development of ATAGS, 

and the RIAGS concept was dropped.226

SUMMARY

The past decade has seen a resurgence of 

acceleration research, aimed primarily at 

future generations of highly maneuverable 

fifth-generation fighters. These efforts are 

well beyond the scope of this book.
4
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

121

4: Partial-Pressure Suits

Ultimately, the Army’s wartime effort to 

develop a full-pressure suit proved unsuccessful. However, the performance of airplanes, 

particularly a new generation of fighters 

equipped with turbojet engines and a series 

of rocket-powered research aircraft developed 

late in the war, continued to increase. The 

advent of the workable pressurized cockpit 

largely relegated the pressure suit to that of 

an emergency device, much like a parachute. 

What was needed was a garment that offered 

protection in the event of a loss of cabin pressure. At one end of this spectrum was a suit 

that would protect against an engine flameout, 

which would result in a slow decompression, 

since the cabin structure would remain intact 

but the source of pressurization would be 

lost. At the other end of the spectrum was a 

suit that would protect against the explosive 

decompression that would result from the loss 

of the canopy or a similar structural failure. 

In response, the Army began seeking an emergency partial-pressure suit.

All previous American pressure-suit-development work had concentrated on the concept 

of a full-pressure suit. As David Clark, the 

man, once opined, the terms partial-pressure 

suit (PPS) and full-pressure suit (FPS) are not 

particularly descriptive but through common 

usage have become the accepted nomenclature 

for the garments. As ultimately defined, a partial-pressure suit protects its occupant through 

the application of mechanical pressure against 

the skin, all of which may or may not be covered (the head, hands, and feet were often bare 

in early suits). The friction of the fabric on the 

skin offers resistance to motion, and irregularities in body contour result in unequal distribution of pressure, giving both pressure points 

and unpressurized areas. Pressure breathing is 

a key part of any partial-pressure suit, which 

provides sufficient counter-pressure to allow 

exhalation at extreme altitudes. On the other 

hand, the full-pressure suit offers protection by 

applying gas pressure against the skin, creating a mini artificial environment in which the 

occupant can breathe, more or less, normally.1

For a slow decompression, as might happen 

following a flameout of a jet engine, either a 

partial- or full-pressure suit provides adequate 

protection since the pilot has time to close 

his helmet and pressurize the suit. Ultimately, 

of course, the full-pressure suit provides better protection, but if the goal is simply to 

allow the pilot to descend to a safe altitude, 

either suit works satisfactorily. It is a different 

story for an explosive decompression. Most 

operational scenarios from the late 1940s 

show a pilot wearing an unpressurized suit, 

mostly to increase comfort and lessen the 

effort necessary to fly the airplane. Because it 

is a relatively tight-fitting garment, even an 

unpressurized partial-pressure suit provides 

some protection during a rapid decompression. Oddly, although a full-pressure suit 

would seem to be the garment of choice in 

such an event, an unpressurized full-pressure 

suit offers little protection against a rapid 

decompression since it is loose-fitting. To offer 

any protection, a full-pressure suit needs to be 

pressurized to at least a low level all the time.2

PRESSURE BREATHING

In the decade after the Europeans traded 

altitude records, Wiley Post’s prediction that 

aircraft would routinely fly at high altitudes 

came true. As this was taking place, physiologists realized that standard demand-type 

oxygen systems were not adequate for 

extended flights above 30,000 feet. In the 

demand-type system, oxygen only flows 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

122

when a person inhales, and then only as 

much as is required to fill the lungs. Even 

on pure oxygen at 30,000 feet, the law of 

partial pressures results in a severe decline 

in alveolar oxygen saturation levels. At 

43,000 feet, the alveolar oxygen saturation 

produced by ambient pressure can sustain 

consciousness for only a short period.3

During the mid-19th century in Germany, 

Dr. Louis Waldenburg (1837–1881) carried 

out the first experiments on breathing at high 

pressures, generally called pressure breathing 

(more recently called positive pressure breathing, or PPB), in an attempt to cure various 

respiratory diseases. From his, and similar, 

experiments came pneumotherapy, using 

pressure-breathing devices that were often 

called Waldenburg apparatuses. The early 

researchers used intermittent pressure breathing at 22 mm Hg to expand the lungs. It is 

probable that, under certain conditions, such 

breathing may have given some benefit to 

victims of pneumonia or various respiratory 

diseases, but too little was known about the 

physiology involved, and the whole matter 

fell into disrepute and was forgotten.4

In the United States, the Aero Medical 

Laboratory at Wright Field led Army research 

into aviation medicine. In November 1941, 

A. Pharo Gagge (1908–1993) reported for 

active duty, working for Capt. John G. Kearby 

in the Miscellaneous Unit of the Aero Medical 

Laboratory. Pharo Gagge (pronounced like 

baggy) earned his doctorate in physics at 

Yale University in 1933 and joined the John 

B. Pierce Laboratory in New Haven, CT. 

The laboratory, an independent research 

institute affiliated with Yale, was founded in 

1933 across the street from the Yale School 

of Medicine. The laboratory still exists and 

is devoted to “studying the ways biological 

systems interact with their environment.”5

 

In 1950, Gagge became Chief of Medical 

Research for the USAF Surgeon General, and 

from 1955 through 1960, he was Deputy 

Commander and then Commander of the 

Air Force Office of Scientific Research. Gagge 

retired from the USAF in 1963 and returned 

to the Pierce Laboratory.

Kearby was the project officer for the wartime 

full-pressure suit development effort. In early 

December 1941, Kearby asked Gagge what 

effect “supercharging” air into the lungs would 

have on human performance at high altitude, 

believing this might offer an emergency procedure in case of damage to a full-pressure 

suit during a chamber test. Researchers used 

breathing pressures of 4, 7, and 11 mm Hg in 

the altitude chamber, and an oximeter measured a noted increase in arterial saturation.6

Oximetry is the measurement of arterial oxygen saturation by transmitting light through 

a translucent area of a patient, usually the earlobe. In 1939, British scientist Glen Millikan 

developed the lightweight ear-oxygen meter 

and coined the term “oximeter.” Initially used 

to determine oxygen saturation in aviators, by 

1948 a similar device was used to control anoxemia during surgical anesthesia. The Waters 

Company X-350 Oximeter, based on work 

by Earl H. Wood at the Mayo Clinic, was the 

first oximeter to give absolute readings of oxygen saturation without prior adjustment to a 

known concentration. Similar oximeters were 

used during cardiac surgery at the Mayo Clinic. 

The pressure-delivery device used during these 

experiments was a compensated metabolism 

apparatus designed by Gagge when he was at 

the Pierce Laboratory. The tests demonstrated 

that human subjects using pressure breathing 

were able to survive and function effectively 

at higher altitude. In fact, Gagge was able to 

ascend to 46,000 feet in an altitude chamber 

and retain reasonable effectiveness. However, 

by March 1942, Gagge realized that the compensated metabolism apparatus, as a means of 

supplying pressure breathing, was incapable 

of further improvement.7

Standard oxygen masks—all derived from the 

BLB concept originally pioneered at the Mayo 

Clinic—did not work well as pressure-delivery 

devices since increased oxygen flow simply 

pushed the masks away from the face, regardless of how tightly they were cinched around 

the head. A full-face mask, then an integrated 

mask-helmet, eventually addressed this problem and forced oxygen into the lungs. As it 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

123

turned out, this was the easier part of the 

problem. Now, the pilot had to exhale, and 

without external pressure on his chest (which 

normally comes from the ambient air pressure), this proved difficult. Instead of breathing normally, the pilot had to forcibly exhale, 

an action that is not instinctive and takes 

more concentration that one would expect. In 

addition, the lungs are not particularly powerful, as evidenced by the amount of effort it 

takes to blow up a balloon. Researchers found 

that many subjects suffered from collapsed 

lungs while pressure breathing. It was a perplexing problem.

In January 1942, the National Research 

Council Committee on Aviation Medicine 

visited the Aero Medical Laboratory to evaluate pressure breathing. Dr. Eugene F. DuBois 

(1882–1959) was chairman, and the committee included Dr. John F. Fulton of Yale 

University and Dr. Henry C. Bazett (1885–

1950) of the University of Pennsylvania. 

Showing that it is a small world, Pharo Gagge 

and Bazett had previously worked together 

at the Banting and Best Institute for Medical 

Research in Toronto. The committee was 

impressed by the results of the pressurebreathing experiments.8

However, it was immediately obvious to the 

committee that if it was going to use more 

than 15 mm Hg pressure, it would be necessary to apply a balancing pressure on the 

outside of the chest to prevent lung damage 

and to make exhaling easier. In response, 

Dr. Alvan L. Barach (1895–1977), a physician 

affiliated with Columbia University in New 

York who had long specialized in pulmonary 

research, developed a counter-pressure vest. 

Nominally, the vest maintained the same pressure as the oxygen a pilot was breathing. As 

the pilot inhaled, the vest deflated, and when 

the pilot exhaled, the vest inflated, forcing 

the chest inward and helping the pilot exhale. 

Similar vests were developed by Bazett, 

Dr. Walter M. Boothby at the Mayo Clinic, 

and Professor John D. Akerman at the University of Minnesota. Further, it was clear to 

at least Barach and Bazett that if pilots were to 

avoid serious disturbances in the circulatory 

system, it would be necessary to apply similar 

pressures to the abdomen and limbs.9

Under the direction of Kearby, one of the 

companies developing full-pressure suits, B.F. 

Goodrich, fabricated a rubber bladder and 

rigid outer vest to place around the chest wall. 

Essentially, this used the same principle as 

the vests developed by Barach and the others. 

Pharo Gagge used this vest for the first time in 

March 1942, and the vest supported the chest 

sufficiently to allow exhaling against pressures 

of 30 to 40 mm Hg (enough to usefully survive at 50,000 feet for about 30 minutes).10

However, physiologists discovered that lung 

collapse ensued almost as readily when 

pressure breathing with a vest as without it. A 

number of researchers attempted to define the 

factors responsible for lung collapse and eventually traced the phenomenon to a diminished 

cardiac output caused by excessive pooling of 

blood in the veins. The counter-pressure vest 

reduced pooling in the abdomen, and experiments using inflatable trousers (essentially, 

G-suits) prevented pooling in the legs—this 

allowed somewhat higher pressures. Henry 

Bazett ascended to 51,500 feet for 30 minutes using an inflatable vest and trousers, and 

others found it possible to get to 55,000 feet 

using the technique. Ultimately, researchers 

determined this was the maximum altitude 

that could safely be supported using a pressurebreathing mask and counter-pressure vest.11

Work continued to improve pressure-breathing 

equipment. In June 1942, the J.H. Emerson 

Company in Cambridge, MA, specialists 

in medical respiratory equipment and iron 

lungs, developed a modified A-12 demand 

regulator that supported pressure breathing. 

At the same time, Capt. Francis E. Randall 

at the Aero Medical Laboratory used anthropomorphic facial measurements to develop a 

mask that allowed pressure breathing while 

remaining relatively comfortable to the wearer. 

The prototype Randall mask was designated 

Type XA-13, and the Army requested further 

development from the Mine Safety Appliances 

Company in Pittsburgh, PA (a company with 

a long history of research on mining breathing 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

124

systems). In November 1942, Randy Lovelace 

tested the Emerson valve and A-13 mask 

aboard a B-17E flown by Boeing test pilots 

Al C. Reed and Jim Frasier to 43,600 feet. 

Using data from the flight, Bradford Holmes 

of the Pioneer Bendix Company simplified the 

Emerson regulator so that a single knob controlled the exhalation pressure and diaphragm 

pressure. Lovelace and Lockheed test pilot 

Joe Towle tested an early Holmes pressurebreathing regulator in a two-seat Lockheed 

P-38 Lightning to 45,000 feet over Burbank, 

CA, in April 1943.12

In May 1943, the Joint Services Pressure 

Breathing Conference convened at Wright 

Field to discuss the status of various experiments. By this time, several leading authorities 

in the field of respiration had expressed considerable disbelief that pressure breathing provided any benefit, especially at the relatively 

low pressures used by the Army. For instance, 

Dr. Douglas R. Drury at USC believed that 

pressure breathing afforded protection only 

when used at very high levels. He thought 

the enthusiasm for pressure breathing and 

for increased altitude performance resulted 

from “high motivation rather than improved 

physiology.”13 Later, this opinion would prove 

substantially correct.

Despite the contrary opinions expressed during the conference, Capt. Norman Molomut 

of the Aero Medical Laboratory demonstrated 

pressure breathing at 48,000 feet in the 

Wright Field altitude chamber.14 Pharo Gagge 

later stated that “the doubting Thomases 

still remained, as several even questioned 

the accuracy of our altimeters and even the 

mercury barometers. All calibrations later 

proved accurate.”15

During the conference, Bazett used an 

ensemble consisting of a pressure-breathing 

mask, a pressure vest, and an early G-suit to 

demonstrate the altitude gains possible while 

pressure breathing at 35 mm Hg. However, 

the ensemble did not provide sufficient counter-pressure, and Bazett had to discontinue 

the experiment without demonstrating a convincing gain in altitude over pressure breathing without any counter-pressure clothing. 

Nevertheless, Bazett stated that he thought 

it possible to use a similar ensemble for short 

fights up to 55,000 feet. The RAF seemed 

particularly interested in pressure breathing 

since it would allow a relatively quick method 

of improving the operational altitude of reconnaissance aircraft. Bazett worked with the 

Royal Aircraft Establishment at Farnborough, 

England, to develop a pressure-breathing 

apparatus that the British quickly pressed into 

service. The RAF would refine this basic technology for the next six decades.16

Pharo Gagge, on the other hand, was generally opposed to counter-pressure clothing, 

feeling that it overly complicated the military 

aspects of flying. At the same time that Bazett 

was working with the British, Drury at USC 

conducted a separate evaluation of a breathing 

vest combined with inflatable trousers. He 

was unable to demonstrate any significant gain 

in pressure tolerance and dismissed the concept as impractical. This soon became 

the USAAF position, the successes by the 

RAF notwithstanding.17

By the end of 1943, the Aero Medical 

Laboratory and its contractors had largely 

abandoned efforts to gain altitude using 

counter-pressure clothing, settling instead for 

the slightly lower altitudes afforded by pressure 

breathing alone. The 28th Photographic 

Reconnaissance Squadron at Peterson Field, 

CO, conducted operational flight tests of 

the pressure-demand oxygen system in early 

October 1943. Based on the encouraging 

results of these tests, the USAAF issued 

contracts to Mine Safety for 4,000 Type A-13 

masks packaged with Type A-14A regulators 

supplied by the ARO Corporation. The 14th 

Photographic Reconnaissance Squadron flew 

the first operational combat mission with 

the new equipment in February 1944, using 

Supermarine Spitfire PR.XI aircraft.18 By 

late 1944, the Biophysics Branch of the Aero 

Medical Laboratory, under the leadership 

of Pharo Gagge, had equipped all Lockheed 

F-5 Lightning and Boeing F-13 Superfortress 

reconnaissance aircraft with the Type A-13 

masks and Type A-14A regulators.19
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

125

The United States operated several Supermarine Spitfire 

PR.XI photo-reconnaissance aircraft and these became the 

first users of the new Type A-13 oxygen mask and Type 

A-14A regulators.

National Museum of the U.S. Air Force Collection

S-1—GENESIS OF THE PARTIALPRESSURE SUIT

In February 1943, the Office of Scientific 

Research and Development (OSRD) awarded 

a small contract to the University of Southern 

California (USC) Aeromedical Laboratory for 

the further development of counter-pressure 

and acceleration protective clothing.20 Executive Order 8807 created the OSRD on June 

28, 1941, to coordinate scientific research 

for military purposes during World War II. It 

superseded the work of the National Defense 

Research Committee and had virtually 

unlimited access to funding and resources. 

Former NACA chairman Vannevar Bush, 

who reported directly to President Franklin 

Delano Roosevelt, headed the organization. 

The research involved new and more accurate 

bombs, reliable detonators, work on the proximity fuze and radar, more effective medical 

treatments, and (most secret of all) the “S-1 

Section,” which later became the Manhattan 

Engineering District and developed the first 

nuclear weapons. Although contracted and 

funded by OSRD, the Aero Medical Laboratory at Wright Field had technical cognizance 

over the USC research.21

As World War II progressed, the USC Aeromedical Laboratory became increasingly busy, 

so the researchers turned many of the lesser 

tasks over to a young researcher named James 

Paget Henry (1914–1966). Henry was born 

to an American father and British mother and 

graduated from Sidney Sussex College in 1935. 

He earned a master’s degree from Cambridge 

University in 1938, an M.D. from USC in 

1952, and a Ph.D. from McGill University, 

in Montreal, Canada, in 1955. Henry initially 

specialized in acceleration physiology using 

the USC human centrifuge from 1943 to 

1947 and designed the first partial-pressure 

suit. In 1947, Henry moved his pressure suit 

work from USC to Wright Field as the Chief 

of the Acceleration Unit of the Aero Medical 

Laboratory. The following year he became a 

naturalized American citizen. During the early 

1950s, Henry was the director of the Air Force 

Physiology of Rocket Flight research project 

and, in May 1952, supervised some of the first 

successful animal rocket launches at Holloman 

AFB, NM. He then became the director of 

the Project Mercury animal research effort 

for NASA. Henry left NASA in 1965 and 

returned to USC as a professor of physiology.22
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

126

In late 1943, a group from USC arrived at the 

Mayo Clinic to study the human centrifuge 

in preparation for building a similar device 

in Los Angeles. Included in the group were 

Dr. Douglas R. Drury, Dr. William G. 

Clark, and Jim Henry from the Departments 

of Physiology and Aviation Medicine.23

E.J. Baldes introduced each of the members, 

including Henry, to David Clark who was 

at Mayo observing G-suit tests. A few weeks 

later, Henry asked Clark for assistance 

developing a new type of counter-pressure 

suit. Unfortunately, Clark had to decline since 

his small company was overwhelmed with 

orders for G-suits and other war material. 

However, Clark offered to send materials, an 

industrial sewing machine, thread, and the 

services of his former experimental seamstress, 

Julia Greene, who had recently relocated with 

her husband to Burbank, CA. David Clark 

even agreed to pay Greene’s salary while she 

assisted the USC team.24

By this time, USC had become the only 

group in the United States studying pressure 

breathing. In November 1943, Douglas Drury 

assigned Jim Henry to lead a group to investigate the issues associated with pressure breathing. The researchers determined that as long 

as the lungs were not allowed to overexpand, 

almost any pressure could be used without 

danger of aeroemphysema (a swelling condition caused by the formation of gas in body 

tissue). This relieved their fear of lung damage 

while breathing at high pressures. In response 

to this finding, the group embarked on the 

development of a full-face, high-pressure 

breathing mask, which would prove crucial 

for Henry’s pressure suit.25

During a symposium at Mayo Clinic in early 

1944, Dr. Harold Lamport of Yale University 

presented a paper on using external longitudinal bladders that could, when inflated, 

tighten a counter-pressure suit evenly and 

comfortably using interdigitating tapes and 

the so-called “capstan effect.” Helen Lester 

and David C. Spooner at the Electric Blanket 

Division of General Electric had developed 

the concept in consultation with Lamport 

during 1943 in an attempt to revolutionize 

G-suits. However, tests on the Wright Field, 

Mayo Clinic, and USC centrifuges showed 

the General Electric G-suit provided no 

meaningful protection. However, the capstan 

idea struck a chord with Henry, who adopted 

it for use with his counter-pressure suit.26

Although the G-suit itself proved ineffective, 

the capstan and pneumatic lever principle, 

along with the lace-adjustment feature, would 

shape most early partial-pressure suits.

The primary difference between a G-suit 

and pressure-breathing suit was the amount 

of time available to inflate the capstans. A 

G-suit needs to react quickly to a changing 

acceleration environment, inflating and deflating rapidly to provide protection for the pilot 

without overly hindering actions. The pressure-breathing garment, on the other hand, 

could inflate relatively slowly and, generally, 

once inflated it stayed inflated for a prolonged 

period. Although the capstans could not 

respond quickly enough to provide meaningful acceleration protection, they seemed excellent candidates to provide counter-pressure 

over large areas of the arms and legs and, 

somewhat later, the shoulders and back.

In April 1944, the Requirements Division at 

the Office of the Assistant Chief of Air Staff, in 

Washington, DC, asked the OSRD to investigate new types of pressure suits to replace the 

failed Army effort to develop a full-pressure 

suit.27 Specifically, the requirements were for a 

suit capable of operating at 60,000 feet for at 

least 30 minutes, while allowing a crewmember to perform his duties with no permanent 

medical consequences.28 The OSRD assigned 

the task to Henry at USC. 

Around the same time, the Army asked Dr. 

Shannon Allen at the Aero Medical Laboratory to develop an emergency get-me-down 

pressure suit for use with the Bell XS-1 (X-1) 

research airplane, and Shannon awarded USC 

a small contract, which quickly found its way 

to Henry.29

These efforts were of particular interest to 

Lockheed, which was located just up the 

road from USC and, coincidently, employed 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

127

Greene’s husband. Engineers, led by Clarence 

L. “Kelly” Johnson, William P. Ralston, and 

Don Palmer at the Lockheed Skunk Works 

were busy developing the second American jet 

aircraft. In theory, the new P-80 Shooting Star 

would be capable of much greater operational 

altitudes than the piston-powered fighters of 

the era, and Lockheed engineers led by Lloyd 

W. Jedeka wanted to know if the new pressure 

suit being developed by Henry could operate 

at 55,000 feet. 

Henry Bazett, representing the Canadian 

Associate Committee on Aviation Medical 

Research visited USC in late April 1944 at 

the request of the National Research Council 

to demonstrate the pressure vest and mask 

he had developed for the RAF. Using the 

Bazett vest and mask and a modified version of the unsuccessful G-suit developed by 

General Electric and Harold Lamport, Henry 

made a new type of altitude suit christened 

a partial-pressure suit to differentiate it from 

the full-pressure suit effort that the Army had 

cancelled in late 1943.30

The garment began with a set of long-sleeve 

coveralls. A large belly bladder, lifted directly 

from a David Clark G-suit, provided pressure to the torso. Capstans and interdigitating 

tapes covered the thighs and calves to provide 

counter-pressure when needed. The capstans 

consisted of a molded, cold-resistant neoprene 

tube inside a cloth sheath. When the capstan 

inflated, interdigitating tapes transmitted 

the sheath tension to the cloth encircling the 

extremity. The advantages of the pneumatic 

lever (capstan) over the inflatable bladders 

used in early G-suits were that there were no 

bladders in direct contact with the legs and 

the pressure was applied more evenly over 

a larger skin area, minimizing discomfort. 

Since the Army expected the partial-pressure 

suit to be used for prolonged periods, at 

least compared with the few seconds or minutes a G-suit was typically inflated, this was 

an important consideration. The suit used 

the standard Army A-13 oronasal pressurebreathing mask equipped with a WildhackLinde compensated exhalation valve and a 

microphone. A set of Polaroid-GE electrically 

heated B-8 goggles completed the ensemble.31

At this point, the suit covered the torso and 

legs, but left the head, arms, hands, and feet 

Kelly Johnson was a driving force behind the first operational 

American jet fighter, the P-80. He would later drive the 

development of the first Mach 2 fighter (the F-104), the U-2 

spy plane, and the Blackbird series of Mach 3 reconnaissance 

aircraft. All of these aircraft placed new demands on the 

pressure-suit industry.

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

128

unprotected. Henry conducted the first test in 

the USC altitude chamber on November 16, 

1944, with generally positive results. However, 

based on early tests, several changes were made 

to the garment. For instance, the jock strap 

that held the pressure vest in place proved 

somewhat uncomfortable, so Henry extended 

the vest bladder down over the perineum32 to 

provide protection against aeroemphysema. 

To provide mobility, he added transverse break 

lines to the ventral part of the bladder at the 

natural bend line at the waist. Henry added 

capstans over the arms and extended them 

across the shoulders and up to the neck. In 

their inflated states, the capstans were 3 inches 

in diameter on the thighs, 2 inches in diameter 

on the calves and upper arms, and 1.5 inches 

in diameter on the forearms. The capstans 

had a volume of approximately 1 liter and an 

expansion ratio of 5:1. Henry added a soft 

leather cap to cover the head, but the suit still 

did not include gloves.33

In December 1944, Henry took the modified 

suit to 58,000 feet (59.5 mm Hg) for 9 minutes before things began to go wrong. Henry 

was somewhat anoxic, but responsive to the 

observers, when his neck and hands began 

to swell grotesquely. Technicians brought the 

USC altitude chamber down to 40,000 feet 

and the swollen areas returned to normal.34

The swelling disturbed researchers, although 

it was not altogether unexpected since earlier 

tests by Harry Armstrong using rabbits had 

shown the possibility of serious gaseous swelling. When the ambient pressure surrounding exposed parts of the body fell below the 

combined pressure exerted by the water vapor, 

carbon dioxide, and oxygen tension in the tissues, the exposed region would swell, often 

grotesquely. The obvious conclusion was that 

water in the hands had vaporized—boiled is 

the more common term, although technically 

incorrect—because they were unprotected. A 

subsequent series of experiments using cats and 

rabbits showed that unprotected extremities 

expanded above 55,000 feet but returned to 

normal at 40,000 feet, with no harmful aftereffects to the muscles and no hemorrhages.35

Henry soon discovered that he could control 

the swelling using tight-fitting gloves. After 

trying rubber and nylon, Henry settled on a 

set of carefully fitted kid leather gloves that 

controlled the aeroemphysema. He also incorporated a set of inflatable socks made by the 

Hood Rubber Company. Interestingly, the 

Harvard Fatigue Laboratory developed these 

socks while researchers were studying trench 

foot. Later suits used standard flying boots that 

contained a vinyl nylon bladder between the 

fleece lining and the outer cover of the boot.36

By the end of 1945, Henry had tested his suit 

during 30-minute runs in the USC altitude 

chamber at sea level and at 25,000, 50,000, 

55,000, and 60,000 feet with satisfactory 

results. Although not tested above 60,000 feet, 

the suit demonstrated there was no particular 

altitude limit at which it could be used, provided adequate counter-pressure was applied 

across the tympanic membrane. Henry 

believed that, “some subjects might be able to 

employ the equipment in its present form for 

short periods (5-10 minutes) in a vacuum.”37

Henry delivered his first prototype 

partial-pressure suit to Wright Field in 

February 1946. The suit imposed counterpressure on the body using inflatable bladders 

in the back, chest, and abdomen aided by 

capstans running along the shoulders, arms, 

and legs. When these capstan tubes were 

inflated, a series of interdigitizing tapes 

applied approximately 10-psi mechanical 

counter-pressure to the limbs.38 Although 

it was universally known as the Henry Suit, 

the Army called it the Type S-1, beginning a 

long line of rather disjointed and confusing 

designations for all types of pressure suits.39

Soon afterward, Pharo Gagge at Wright Field 

called David Clark and asked if he would be 

interested in producing a version of the 

Henry Suit. Clark traveled to Wright Field 

to observe tests of the prototype Henry Suit 

that Julia Greene had sewn. These tests used 

the Guardite Strato Chamber at the Oxygen 

Equipment Test Laboratory at Wright Field. 

During each run, an experienced chamber 

operator was present in the small airlock at 
Dr. James P. Henry at the 

University of Southern 

California, developed the 

first workable partialpressure suit. The finished 

Henry Suit was a tightfitting coverall that had 

capstans running from the 

ankles to the waist and 

from the neck to the wrists. 

In their inflated states, 

the capstans were 3 inches 

in diameter on the thighs, 

2 inches in diameter on 

the calves and upper arms, 

and 1.5 inches in diameter 

on the forearms. A pair of 

gloves and a leather helmet 

completed the garment.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

130

Even with the capstans 

inflated, the Henry Suit 

allowed sufficient motion 

to perform most tasks 

aboard an aircraft. The 

capstan principle had its 

origins with a failed General 

Electric G-suit and formed 

the basis for most early 

partial-pressure suit in 

the United States and the 

Soviet Union. 

Courtesy of the David Clark 

Company, Inc.

an altitude of 35,000 feet to render aid in 

the event of an emergency descent. The main 

chamber was fitted with a hand-operated, 

quick-acting dump valve that permitted return 

from any altitude to 35,000 feet in less than 

15 seconds. The chamber was, in theory, 

capable of simulating 100,000 feet altitude. 

Henry accomplished runs to 60,000 and 

65,000 feet on March 22, 1946; 70,000 feet 

on March 25; and 75,000 feet on March 29. 

Additional runs were made to 80,000 and 

85,000 feet on May 27 and to 90,000 feet on 

May 31. Henry spent at least 10 minutes at 

each altitude.40

The first three runs used the original soft cap 

and a black rubber inflatable seal that covered 

Henry’s face but not the ears. The cap was 

supposed to overlap the suit at the neck but 

did not quite accomplish this, leaving some 

flesh exposed to the low pressure. Henry 

complained of considerable pain during 

the 60,000 and 65,000-foot ascents, and 

at 70,000 feet he developed fluid in the 

middle ear due to increased capillary filtration as the consequence of greatly elevated 

venous pressure. The fluid was reabsorbed 

uneventfully within 48 hours, but the incident 

conclusively demonstrated the need for ear 

counter-pressure at extreme altitudes.41

Henry replaced the cap with a semi-rigid vinylized rubber helmet that used an A-13 mask 

and B-8 goggles attached to it with rubber 

cement. This helmet was fitted with dipped 

latex bladders that covered the head and neck 

and with a face-sealing bladder fitted into the 

sealing surface of the A-13 and B-8 components. The bladders were inflated 10–15 hmm 

Hg above the breathing oxygen pressure. Initial 

tests showed that the vinylized rubber was 

prone to distortion under pressure, so a stiffening frame made from aluminum tubing was 

placed around the outside of the mask. A zipper in the rubber allowed donning and doffing, 

and laces provided some adjustment.42

The last three runs used this improved rubber 

helmet that provided ear counter-pressure. 

The suit, helmet, and inflated gloves and 

boots all performed satisfactorily and provided sufficient protection against fluid loss 

and aeroemphysema. However, the ensemble 

was uncomfortable at mask pressures above 

100 mm Hg.43

Alice King at the Aero Medical Laboratory 

developed a new helmet that improved on 

the second Henry design. This helmet used 

integrated ear- and face-sealing bladders filled 

with sponge rubber and secured adequately at 

mask pressures up to 170 mm Hg. The helmet 

also included an enlarged neck bladder that 

proved more comfortable than the one used 

on the second Henry helmet.44

Most subjects found the suit in its deflated 

state no more uncomfortable than a tightly 
The original XS-1 series had a remarkably small side hatch 

for ingress and egress; the airplane did not have an ejection 

seat. This is NACA test pilot John H. Griffith in the third 

X-1 (46-063) handing his flight helmet to Crew Chief Dick 

Payne while Edwin “Eddie” Edwards holds the hatch and 

Maintenance Chief Clyde Bailey looks on in November 

1950. Griffith is in a standard flight suit, demonstrating 

how small the hatch is and the difficulty of bailing out with 

a pressure suit. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

132

laced G-suit. The suit, however, restricted 

rotation of the shoulders, making it hard to 

get at the shoulder straps and parachute harness. When seated in an airplane, the suit did 

not restrict the normal movements needed 

to fly, although everybody thought that less 

restriction at the elbows, knees, and shoulders 

would permit a fuller range of motion when 

attempting to bailout of a small hatch, such 

as the one in the XS-1.45

When inflated, the suit felt tight, as it was 

supposed to. With the capstans inflated to 

7 psi, it was still possible to pilot the aircraft 

without undue exertion. At 15-psi inflation, 

the task was possible but very tiring. The 

kid gloves did not significantly affect movement of the fingers, and handwriting samples 

proved quite readable.

Despite its early stage of development, the 

suit worked. For instance, the fluid loss while 

wearing the suit was about 5 cubic centimeters 

(cc) compared to 9 cc using only a pressurebreathing mask and vest. The pulse rate with 

the mask and vest (breathing at 55 mm Hg 

for 30 minutes) was 80–110 beats per minute, 

reduced to 60 to 70 beats wearing the suit. A 

typical subject could not breathe at more than 

40 mm Hg for 30 minutes with the mask and 

vest but could tolerate 85 mm Hg using the 

suit. After 1 hour of preoxygenation, simulated 

30-minute flights at 55,000 feet resulted in 

only a single mild case of the bends. Normally, 

the same individuals using only a mask and 

vest complained of pains after only 15 minutes 

at 40,000 feet.

Nevertheless, the suit was far from perfect. 

Researchers noted aeroemphysema on every 

ascent above 55,000 feet for more than 

15 minutes. Fortunately, it did not lead to 

anything other than a feeling of puffiness and 

distention in the tissues involved. This was particularly true of ascents using the original helmet, in which significant portions of the lower 

head and ears were left exposed. Tests showed 

that if the capstan system failed at 60,000 feet 

(due to a pressure-source failure or a rupture 

in the capstans), the person would still have 1 

to 2 minutes of fully useful activity to respond 

to the situation, compared to only 15 seconds 

available if a full-pressure suit failed.46

Henry and Greene fabricated a second 

suit tailored to fit Bell chief test pilot 

Jack Woolams for use in the XS-1. Researchers 

at the Aero Medical Laboratory tested the 

suit to 55,000 feet, about all the XS-1 would 

reach during its initial tests. After the altitude 

chamber tests at Wright Field, Woolams 

evaluated the suit at the X-1 test site at 

Pinecastle AAF, FL. When he tried the suit 

on, Woolams commented that the suit was 

sufficiently comfortable in its deflated state 

and that the helmet and full-face mask were 

more comfortable than the oxygen masks 

in operational service. When the suit was 

inflated, Woolams found that the mobility 

of his arms, in particular, was significantly 

impaired, but it was still possible to execute 

all the motions necessary to fly the XS-1.47

However, further testing revealed that the 

suit, as delivered, was not satisfactory, largely 

because the oxygen mask and helmet used 

with it caused intense pain in the ears during 

pressure breathing.48

Obviously, further development was needed. 

Fortunately, Wright Field had $20,000 

available for pressure-suit procurement. In 

February 1946, Col. Bruce B. Price, acting 

chief of the Aircraft and Physical Requirements 

Branch of the Engineering Division, stated 

that only two manufacturers were qualified to 

develop a capstan-type partial-pressure suit: 

the General Electric Company in Bridgeport, 

CT, and the David Clark Company. General 

Electric, however, had already expressed a 

decided lack of interest in the project.49

On February 28, 1946, the Air Materiel Command executed a contract (W33-038-ac-15165) 

with David Clark for four modified versions 

of the Henry Suit. David Clark told Wright 

Field the first suit would be delivered by April 

19 at a cost of $1,500. The second suit, to 

be delivered a month later, would be tailored 

for Jack Woolams. Unfortunately, a crash on 

August 30, 1946, killed Woolams while he was 

preparing a modified P-63 for the Thompson 

Trophy Race in Cleveland, OH.50
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

133

David Clark called Julia Greene and invited 

her to come to Worcester, MA, for a month 

to help sew the Henry Suits. Greene had 

been in California for over a year at this 

point and was happy to return and visit her 

friends. After explaining the difficulties she 

had encountered making the Henry Suits 

in California, Greene and Clark decided to 

start over. First, they determined the correct 

locations on the elbows, shoulders, hips, and 

knees for the capstans that would prevent 

them from doubling-up and inhibiting 

mobility. The pair paid special attention to 

the elbow and knees to keep the fabric biases 

correct to improve mobility.51

In consultation with Pharo Gagge and others 

at Wright Field, David Clark made numerous changes to the suit. Most importantly, 

capstans replaced the breathing bladders in 

the back, chest, and abdomen, reducing the 

discomfort and sweating associated with the 

poorly ventilated areas under the bladders. 

The lacing adjustments were extended to 

include the torso and extremities. He changed 

the material from cotton to a porous nyloncotton blend, improving the strength of the 

garment and providing better ventilation. 

Clark cut the cloth on the bias to provide 

a uniform distribution of pressure and 

changed its color from black to sage green 

to conform to military clothing standards. 

Two zippers extending from the collar, down 

over the shoulders, and to the upper part of 

each arm replaced the original ventral zipper. 

This prevented the complete loss of counterpressure in the event of a zipper failure and 

made donning and doffing the suit easier. 

Clark tailored the suits in a normal sitting 

position to permit maximum mobility with 

minimal discomfort.52

Capt. Harold J. “Jake” Jacobs soon arrived 

in Worcester for a fitting since he was the 

primary test subject for the first suit.53 Jacobs 

would play a major role at Wright Field during pressure suit development, but he would 

ultimately leave the military and join the staff 

of Charity Hospital in New Orleans. David 

Clark delivered the first modified suit, fitted 

for Jacobs, in April 1946. The Army still used 

the S-1 designation for the suit, although it 

was considerably different from the original Henry Suit. The suit also included an 

improved pressure helmet developed by Alice 

King at the Aero Medical Laboratory and a 

special ear counter-pressure device.54

With one exception, the Army meant the 

S-1 suit to be a get-me-down garment 

to protect the pilot in the event of cabin 

pressurization failure at high altitude or if the 

pilot bailed out. Nobody intended to use the 

suit for extended periods. The exception was 

the XS-1 program, although even this was 

not an “extended” period since the rocketpowered airplane only flew for a few minutes 

at a time. 

Once Jacobs had proven the basic suit in the 

altitude chamber, David Clark fabricated suits 

for Bell test pilot Chalmers H. “Slick” Goodlin 

and USAF test pilots Capt. Frank K. “Pete” 

Everest, Jr., Capt. Robert A. Hoover, and 

Capt. Charles E. “Chuck” Yeager. The Army 

had already added funds to the contract to 

cover the additional suits. The man who had 

taught David Clark to fly at the Worcester airport, Joseph A. Ruseckas, frequently played air 

taxi pilot, for instance, shuttling Hoover and 

Yeager from the Westover airport to Worcester. 

By now, the helmets being built by Alice King 

at Wright Field had expanded plexiglass that 

covered the ears, although the top and back of 

the head were still covered only by rubberized 

nylon fabric. Within a few months, Wright 

Field had changed the vacuum pumps on the 

Guardite Strato Chamber and tested the suit 

to 106,000 feet—a new record—using Jacobs 

as a test subject.55

In August 1946, the David Clark Company 

contract was amended to furnish 10 additional 

partial-pressure suits at a total price of $4,999, 

all for delivery within 60 days. These were generally similar to the earlier suits but incorporated improved gloves and boots.56 The Army 

subsequently included these S-1 suits as part of 

Project MX-829 (SEO 660-141), which would 

evolve to include the first operational S-2 and 

T-1 suits. This would complicate future procurements since MX-829 was classified “confidential”—secrecy was unfamiliar in academia 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

134

and relatively new to many of the small companies that would play a major role in future 

developments. This was especially true at the 

University of Southern California, mostly 

because Jim Henry was a British national.57

On October 14, 1947, Capt. Charles E. 

“Chuck” Yeager became the first human to 

purposely break the speed of sound in level 

flight when he recorded Mach 1.06 at 

43,000 feet in a Bell XS-1 (46-062). Despite 

many reports that Yeager was wearing the 

S-1 suit that the David Clark Company had 

manufactured for him, in fact he wearing only 

his normal flight suit. Dr. James O. Young, 

the historian at the AFFTC at Edwards, queried Yeager about this, and Yeager responded 

that he did not wear his pressure suit for any 

of the 1947 flights since he did not attempt 

to fly above 48,000 feet.58

After much discussion and personal debate, 

Jim Henry filed for a patent on his partialpressure suit on April 13, 1948. Originally, 

he had wanted to name several others as 

co-inventors but ultimately filed the patent 

in his name alone and assigned the rights 

to the United States of America as represented by the Secretary of the Air Force. 

The patent (2,886,027) was finally granted 

on May 12, 1959.59

By May 1948, the USAF deemed the partialpressure suit mature enough to enter limited 

production. David Clark Company received 

a contract amendment to deliver 10 suits 

that incorporated integral G-suits at a total 

price of $10,000. In addition, the Government directed the company to provide the 

patterns necessary to produce the suits in 

five sizes: extra small, small, medium, large, 

and extra large. The USAF would use these 

suits to develop further sizes for standardization and to write procurement specifications. 

Eventually, the USAF dropped the extra-small 

size, and the others each came in short, regular, and long variants, resulting in 12 available 

sizes.60 To support the sizing efforts, the Aero 

Medical Laboratory conducted an anthropometric survey, making 132 measurements of 

more than 4,000 men.61

For its part, David Clark Company also had 

to grow. A friend told David Clark that Joe 

Ruseckas was looking for a job since the 

postwar economy was taking a toll on general 

aviation. At the time, Ruseckas was a flight 

instructor at the Worcester airport, continuing his love of flying that had taken him over 

the Hump many times during World War 

II. Clark immediately hired him as a pattern 

maker, which somewhat confused Ruseckas 

since the only patterns he was familiar with 

were the ones you flew around an airport. It 

was the beginning of something special.62

In 1932, when he was 15, Ruseckas began 

doing odd jobs around the Worcester airport. 

The production S-1 suit looked very much like the original 

Henry Suit except for the new K-1 helmet. The initial S-1 suits 

were tailored for the test pilots assigned to the X-1 program 

and Maj. Frank K. “Pete” Everest, Jr., became the first to use 

the suit under emergency conditions, on August 24, 1949, 

after the canopy on the X-1 cracked and the cockpit depressurized. Note the helmet restraint cord on the chest.

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

135

He became a private pilot, then an instructor 

pilot, and finally a Civil Aeronautics Administration (CAA, the predecessor of the Federal 

Aviation Administration) examiner. During 

World War II, he joined the Army Air Corps, 

ferrying fighters around the U.S. and eventually flying a Curtiss C-46 Commando over the 

Hump in the China-Burma-India Theater. He 

joined David Clark Company in 1948 and 

participated in the development and fielding 

of almost every pressure suit manufactured by 

the company. Ruseckas retired in December 

1986 after 38 years with the company and 

passed away on March 19, 2010.63

On June 21, 1948, the Aero Medical Laboratory held a conference at Wright Field to 

discuss the future of Project MX-829. The 

ensuing discussion brought several interesting points to light. Researchers had largely 

directed past work toward developing a 

satisfactory high-altitude pressure suit for 

“sonic-type” aircraft, namely the rapidly 

developing turbojet fighters and rocket-powered X-planes. Because of the high emergency 

rate of descent of sonic-type aircraft, the 

laboratory had experienced little difficulty in 

providing an emergency oxygen system to get 

the pilot to an altitude where it was possible 

to breathe. However, bombardment aircraft 

like the Convair B-36 and Northrop B-49 

might have the emergency descent rates as 

low as 1,000 feet per minute, requiring over 

15 minutes to reach a breathable atmosphere. 

Researchers were now faced with ensuring 

that the partial-pressure suits, helmets, regulators, and oxygen-storage systems were capable 

of operating for much longer times than originally expected.64 It is ironic that partial-pressure suits, originally designed for supersonic 

research airplanes, would ultimately find their 

first operational use in the slow-flying, pistonengine Convair B-36 very-heavy bomber.

Attendees at the conference concluded that 

the existing suit design had to be standardized and production sources identified. In 

addition, the attendees emphasized that the 

suit had to be comfortable when uninflated 

because the crews could only tolerate the 

discomfort of an inflated suit during emergencies. The researchers defined tolerance and 

stated that, “operating standards must not 

be lowered. The user must not forget routine 

checks. The attention span must not be narrowed. There must be no less of ability in performing complex motor and mental functions, 

and one’s judgment must not be impaired.”65

In January 1949, Maj. Gen. Franklin O. 

Carroll suspended further X-1 flights above 

50,000 feet altitude pending “certain known 

improvements to flying clothing to add to 

the pilot’s comfort and to the safety of both 

airplane and pilot.”66 This was not a major 

issue since the X-1 had been designed to 

exceed Mach 1 in level flight, not to explore 

the high-altitude regime. Nevertheless, by 

the beginning of 1949 the airplane had 

exceeded 50,000 feet on at least three occasions, including one to 60,000 feet on 

May 26, 1948, with Chuck Yeager at the controls. The restriction did not, apparently, last 

long, and Capt. Jackie L. “Jack” Ridley took 

the first X-1 to 51,700 feet on April 29, 1949, 

and Maj. Frank K. “Pete” Everest, Jr., set the 

maximum altitude for the basic X-1 program 

of 71,902 feet on August 8, 1949.

Only 2 weeks later, the partial-pressure suit 

proved its worth. On August 25, 1949, 

Pete Everest was flying the first X-1 when the 

canopy cracked and the cockpit depressurized. His partial-pressure suit automatically 

inflated, allowing him to continue breathing. 

He landed, uncomfortable, but unhurt. This 

was the first recorded use of a partial-pressure 

suit under emergency conditions.67

S-2 AND T-1—PRODUCTION PARTIALPRESSURE SUITS

On September 2, 1949, in a letter to the 

Engineering Division, Pharo Gagge summarized the production possibilities for the 

partial-pressure suit and its component parts. 

In particular, Gagge believed the David Clark 

Company had the knowledge and shop 

facilities to put the modified Henry Suit into 

production immediately, based largely on its 

wartime experience manufacturing G-suits 

and the postwar fabrication of a few dozen 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

136

S-1 suits. Eventually, five vendors were qualified to manufacture the suits, including David 

Clark Company, H.I. Garment Company of 

Chicago, Kops Brothers of New York City, 

Drybak Corp. of Bingham, NY, and Berger 

Brothers of New Haven, CT.68

In addition to the S-2 suit (DCC Model S394) 

that was derived from the modified Henry 

Suits, the USAF also defined a T-1 suit (S393) 

that was identical to the S-2 except that it 

incorporated the acceleration-protection 

features of the G-4A G-suit. The T-1 was 

recognizable by having two air connections, 

instead of the single connection of the S-2 

suit. The USAF used the S-2 in bomber and 

reconnaissance aircraft, while the T-1 suit was 

used in fighters and experimental aircraft, 

where acceleration protection was desirable. 

The suits provided identical protection from 

short exposures to unpressurized environments 

up to 65,000 feet. Even as the suits were entering the inventory, the USAF indicated that the 

suit “in its present form is not a ‘space suit;’ 

nor is it the ‘ideal’ long-range pressure suit.” 

However, the S-2 and T-1 fulfilled the original 

MX-829 requirement to “provide a practical 

and dependable emergency garment for use at 

extremely high-altitudes for short periods of 

time.”69 It was a start.

In October 1949, the David Clark Company 

shipped a prototype 5.3-pound T-1 suit to 

the Aero Medical Laboratory for evaluation.70

Maj. Clarence C. Cain and Capt. David I. 

Mahoney tested the suit since both wore 

medium-regular size. The laboratory subsequently advised the company that three individuals had tested the suit and found 

no discrepancies.71

Coincident with these activities, the Aero 

Medical Laboratory and David Clark 

Company had been working on defining 

12 standard sizes for all future flying suits. 

On January 12, 1950, David Clark submitted a Tariff of Sizes (dated January 3) 

that was approved by the Aero Medical 

Laboratory 2 weeks later. These became 

the standard sizes—small, medium, large, 

and extra large, each in short, regular, and 

long—for all flying clothing from all suppliers, not just David Clark Company. These 

sizes accommodated 92 percent of all USAF 

pilots. The Berger Brothers pressure suit 

contract included provisions for custom 

tailoring to fit the remaining 8 percent of 

the population.72

Convair test pilots Arthur 

S. “Doc” Witchell and James 

D. “J.D.” McEachern wear 

S-2 partial-pressure suits in 

preparation for a test flight in 

a B-36 on October 19, 1952, 

at Fort Worth, TX. Note the 

variety in footwear. 

Courtesy of the Frank F. 

Kleinwechter Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

137

The official history of the T-1 suit summarizes 

its benefits:

The T-1 suit differed from all that had 

gone before in that it resembled neither 

the suits developed by other countries 

nor the earlier, cumbersome full-pressure 

suits constructed in the United States. 

Based on an unique mechanical partialpressure principle and designed purely as 

an adjunct to the pressure cabin, the T-1 

was simply and solely an emergency, or 

as the British called it, a ‘get-me-down’ 

article of clothing. It was a light and flexible type of coverall fitted with capstan 

tubes. In the case the airplane depressurized suddenly from any cause, a valve in 

the suit’s oxygen supply automatically 

opened and provided the wearer with the 

same environment, sort of, that he would 

have encountered at 40,000 feet. Oxygen 

was forced into the capstan tubes, which 

grew in diameter, and pulled cloth levers 

that tightened the suit so that counterpressure was applied against the body. 

The counter-pressure enabled the body 

to withstand the internal reaction to the 

very great pressure of the oxygen being 

forced into the lungs. The flyer only 

had to keep exhaling, something easier 

said than done even with the counterpressure. Inhaling was done automatically 

as the regulator forced oxygen into the 

lungs. The purpose of the T-1 suit was to 

allow the crew time to either bail out of 

a stricken aircraft, or to maneuver a controllable airplane to a lower, safe altitude. 

The suit was not suitable for constant use 

in lieu of a pressurized cabin.73

On December 16, 1949, North American 

Aviation wrote the Aero Medical Laboratory 

inquiring about the availability of pressure 

suits for use by company test pilots flying the 

YF-86D and YF-93A, both of which were 

capable of operating above 50,000 feet. The 

company wanted to purchase or borrow suits 

as the laboratory felt best. Other companies 

made similar requests over the next year.74

Col. Walter A. Carlson responded to North 

American that the Government might furnish 

T-1 suits, although the suit was still under 

development. The North American pilots 

selected to wear the suit would have to travel 

to Wright Field for indoctrination.75

On May 30, 1950, the Air Materiel Command 

awarded a contract, AF33(038)-13028, to 

The first true production partial-pressure suit was the 

S-2 that was derived from the modified Henry Suits (S-1). 

The USAF also ordered a T-1 suit that was identical to the 

S-2 except that it incorporated the acceleration protection 

features of the G-4A G-suit. The T-1 was recognizable by 

having two air connections instead of the single connection 

of the S-2 suit. The USAF used the S-2 in bomber and 

reconnaissance aircraft, while the T-1 suit was used in 

fighters and experimental aircraft where acceleration 

protection was desirable. This February 9, 1954, photo 

shows a T-1 with its K-1 helmet.

U.S. Air Force
Chapter 4: Partial-Pressure Suits

138

Frank K. “Pete” Everest, Jr., 

in a T-1 partial-pressure 

suit standing in front of the 

Bell X-2 holding the rubber 

bladder he wore under his 

K-1 helmet. Everest became 

known as the “fastest man 

alive” after he took the X-2 

to 1,900 mph (Mach 2.87) 

on July 23, 1953.

U.S. Air Force

David Clark Company for 251 S-2 and 

T-1 suits under specifications MIL-Y-3278 

and MIL-Y-3280, respectively. David Clark 

Company bid $372.60 per suit, but the 

final negotiated price was $344.62 per suit, 

for a total of $86,155. Two complete sets 

of underwear were included with each suit. 

The delivery of the first suit was expected 

in 90 days, with the remainder within 

150 days.76 By this time, the USAF had 

determined the partial-pressure suit would 

be a desired safety item below 50,000 feet 

and mandatory for flights above 50,000 feet. 

All North American F-86D/E Sabres and 

Lockheed F-94B/C Starfires produced using 

fiscal year 1950 funds were equipped to 

accommodate the suits.77

The S-2 and T-1 suits originally used a K-1 

helmet that consisted of a rubber bladder 

that completely covered the head and sealed 

using an inverted flap at the neck. A snug, 

laced-nylon restrainer and a close fitting, 

two-part (split) white outer shell limited the 

ballooning of the bladder. Earphones and a 

microphone were supported by foam rubber 

padding inside the bladder, and a removable plastic faceplate contained the necessary 

breathing valves. An improved K-1 helmet 

used a substantially larger one-piece, (instead 

of split) green fiberglass outer shell. The initial 

(split-shell) K-1 helmets used external antilift 

constraint cable attachments, while the onepiece shell versions moved these internally, to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

139

NACA test pilot Joe Walker used a T-1 suit and K-1 helmet 

in the Bell X-1E as late as 1956. The second X-1 (46-063) 

was modified into the X-1E as much to provide the test pilots 

something to fly while they were waiting for the arrival of the 

North American X-15 as for any specific research purposes. 

Nevertheless, the X-1E provided valuable research in the 

hands of Joe Walker and John B. “Jack” McKay, reaching 

altitudes of over 73,000 feet.

NASA E-3362

the inner, lower rim of the shell. An upgraded 

version of the improved K-1 helmet featured a 

white fiberglass shell, an AIC-10 communication setup, and an improved, high-pressure 

oxygen delivery hose on its faceplate.78

By the time the T-1 partial-pressure suit was 

announced to the public, it had been worn 

more than 700 times in simulated runs above 

63,000 feet in the Guardite Strato Chamber at 

Wright Field and multiple times in the USC 

and Mayo Clinic chambers. Although it was 

reasonably comfortable and satisfactory from a 

functional perspective, the K-1 imposed severe 

limitations on the mobility of the head that 

adversely affected the field of vision, making it 

particularly unpopular with fighter pilots.

The MA-1 helmet was the direct result of 

continued attempts to correct the deficiencies of the K-1. It was designed to serve both 

as an oxygen mask at lower altitudes and as a 

pressure-breathing helmet for use in conjunction with either partial- or full-pressure suits. 

To this end, it was designed with a round 

(rather than oval) base so that it could be used 

with a neck ring and was made tight fitting 

by the use of a special material that resembled 

foam rubber.79

The MA-2, manufactured by the International 

Latex Corporation (ILC), used a white onepiece fiberglass shell. The MA-2 featured 

a longer neckpiece that covered the upper 

chest and shoulders, a deep neck-seal bladder (resembling an inverted “turtle neck”), a 

three-way stretch insert in the neck to increase 

mobility, and a new defogging system and 

oxygen hose. The Strategic Air Command 

(SAC) crews used a similar MB-5 helmet with 

the S-2, MC-1, and MC-3 suits. The MB-5 

was virtually indistinguishable from the MA-2, 

except for an AIC-10 headset.80

On August 15, 1951, Douglas test pilot 

William B. Bridgeman wore a T-1 suit when 

he took the D558-2 Skyrocket to a new 
140

altitude record of 79,494 feet. The partialpressure suits were becoming a standard piece 

of personal protection equipment for the test 

pilots at Edwards.81 NACA test pilot Joseph 

A. Walker, at least, was still using the T-1 suit 

as late as 1956 for flights in the Bell X-1E 

research airplane.

The Department of Defense publically 

announced the T-1 partial-pressure suit as 

the “latest achievement” of the Wright Air 

Development Center on October 4, 1952. 

The announcement informed the public that 

the T-1 “resembles to some extent the popular 

conception of a space suit.”82 Not really, but 

it was good press in any case. Whatever the 

public affairs people were saying, by early 

1953, there were approximately 200 S-2 and 

T-1 suits in the hands of operational personnel. In addition to the USAF, the U.S. Navy, 

Royal Air Force, and Royal Canadian Air 

Force used the suit. Many civilian test pilots 

working on military contracts had also been 

issued suits, including pilots from the Allison 

Lockheed modified three Starfighters into NF-104A aerospace 

trainers by adding a Rocketdyne AR2-3 rocket engine at the 

base of the vertical stabilizer and a reaction-control system. 

Here, Lockheed test pilot Herman “Fish” Salmon shakes 

hands with Chuck Yeager prior to his December 4, 1963, 

flight to 118,860 feet. Yeager is wearing a David Clark 

A/P22S-2 full-pressure suit.

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

141

Division of General Motors, Avro (A.V. Roe 

of Canada, Ltd.), Bell, Boeing, Convair, 

Douglas, Lockheed, Northrop, North American, and Pratt & Whitney.83 In December 

1951, the SAC began issuing the suits to 

B-36 crewmembers.84

Occasionally, a satisfied user thanked the 

researchers at the Aero Medical Laboratory. 

One of these was Lockheed test pilot Herman 

R. “Fish” Salmon. On April 14, 1955, Salmon 

was flying the second XF-104 (53-7787) at 

47,500 feet while wearing a T-1 suit, K-1 helmet, and strap-fastened boots. As he triggered 

the General Electric M61 Vulcan 20 mm 

cannon for a test firing, severe vibrations loosened the floor-mounted ejection hatch and 

the cockpit explosively depressurized at the 

same time as the engine flamed out. The suit 

inflated immediately. Repeated attempts to 

restart the engine failed, and Salmon ejected 

at 15,000 feet. Fish reported, “I landed in a 

field of rocks ranging from one foot to five feet 

in diameter. My right arm was injured and my 

head struck on a rock. The K-1 helmet hard 

shell was cracked, but there was no injury to 

my head. It took me 10 to 15 minutes to get 

out of the suit with my injured arm. Rescue 

was effected [sic] by helicopter approximately 

two hours after escape.” Salmon reported 

that the K-1 helmet was excellent for “rugged 

parachute landings,” and his only complaint 

was that the “visor may impair vision at 

extreme altitudes.”85

MC-1—FEATHERWEIGHT SUIT

Project Featherweight was a major modification that removed most defensive armament and crew comfort items from much of 

the Convair B-36 very-heavy bomber fleet 

to extend the range and increase the combat 

radius of the airplane. The Aero Medical 

Laboratory initiated the development of the 

MC-1 specifically to meet the need of the 

Featherweight B-36 program. In contrast 

to the get-me-down S-2 suit, the Featherweight B-36s needed a suit that provided 

“protection against long-term exposure to altitudes in excess of 50,000 feet.”86 As with most 

partial-pressure suits, the development was 

assigned to the David Clark Company.

A 1952 flight of a B-36 from Carswell AFB 

in Fort Worth, TX, showed the urgency of 

this need. Although a cabin pressure of 

34,000 feet was maintained while the aircraft flew at 50,000 feet, 4 of the 12 crewmembers were stricken with disabling bends, 

and the bomber was forced to make an 

emergency descent that overstressed its six 

Pratt & Whitney R-4360 engines to such 

an extent that all had to be replaced.

The bends, also known as caisson disease, is 

the result of bubbles of nitrogen gas in tissue 

released from solution by pressure change. 

Preoxygenation (denitrogenation)—breathing 

pure oxygen for a period before the anticipated 

event—can alleviate this condition to a certain 

extent. Exactly when, or if, a person gets the 

bends is dependent upon many factors and 

varies greatly from individual to individual.

The B-36 episode accented the need for 

proper cabin pressurization and for breathing 

pure oxygen for a sufficient length of time 

before high-altitude flights. It also graphically 

demonstrated the need for a pressure suit. In 

response, on July 14, 1952, the Aero Medical 

Laboratory demonstrated the S-2 suit—the 

B-36 hardly had a need for the G-suit in the 

T-1—to the SAC using a B-36H that reached 

52,000 feet. Once the airplane reached 

10,000 feet, about an hour after takeoff, 

each crewmember donned his S-2 suit. This 

occupied the better part of an hour, even in 

the relatively spacious rear compartment of 

the bomber. It should be noted that although 

the B-36, especially the Featherweight airplanes, were capable of exceeding 50,000 (and 

possibly 55,000) feet, they took a long time 

to climb to that altitude. B-36 flights typically 

lasted 24 hours, and many lasted almost twice 

that. Until the B-36 reached 50,000 feet, 

the airplane maintained a cabin altitude of 

20,000 feet and the crew breathed pure oxygen during the first 90 minutes of the flight. 

The plan had been to breathe pure oxygen 

for the entire flight, but the flight engineers 

noted the airplane’s supply was inadequate, so 

the crew breathed normal air supplemented 

by oxygen for rest of the flight. Although the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

142

The Convair B-36 drove several requirements for partialpressure suits during the early 1950s. The bomber could fly 

higher (over 50,000 feet in some variants) that any other 

operational aircraft, and frequently flew missions in excess 

of 48 hours (although a very small percentage of this time 

was at high altitude). The aircraft was pressurized and 

heated, but the need for emergency get-me-down suits 

became apparent after several accidents and narrow escapes.

U.S. Air Force

crewmembers were more comfortable while 

breathing pure oxygen, they were still able to 

perform their required duties. The airplane 

remained above 45,000 feet for 3 hours and 

there were no reports of the bends. Several 

crewmembers, however, complained about 

discomfort with the S-2 suit, although everybody accepted the need for such a device.

Notwithstanding the test and the reluctant 

endorsement by the crew, researchers still did 

not know exactly what conditions the SAC 

wanted its partial-pressure suit to accommodate. On May 3, 1953, in response to a 

query by Lt. Col. Clarence C. Cain of the 

Aero Medical Laboratory, the Eighth Air 

Force stated that the B-36 might operate at a 

maximum altitude of 53,000 feet. The nonhuman components of the weapon system 

limited endurance at that altitude, however, 

since engineers doubted that “radar equipment 

will operate reliably at this altitude...it is not 

expected that under any circumstance can 

the B-36 be kept at 53,000 feet for more than 

3 hours on a strike mission.”87

This was somewhat disinformation, since there 

was no intent of routinely flying a B-36 at 

high altitude for any great length of time. The 

popular vision of a strategic bombing mission is that the airplane takes off, climbs to its 

maximum altitude and speed, and flies to its 

target. Even with an all-jet aircraft such as the 

B-52, this is not necessarily true, since long 

range and high speed are usually mutually 

exclusive. Although the B-52 quickly climbs 

to its service ceiling, where its jet engines 

are the most efficient, it settles in at an economical cruising speed for most of the mission, reaching its maximum speed only as it 

approaches enemy airspace.

Piston-powered airplanes, however, used different mission profiles since their engines and 

propellers were not particularly efficient at 

high speeds or extreme altitudes. In the case 

of the B-36, the oft-quoted 400-mph speed 

and 45,000-foot altitudes were only applicable 

for short periods over the target. A typical 

long-range bombing mission for a Featherweight B-36J assumed a target 4,150 miles 

distant, for a total mission of 8,300 miles. The 

outbound cruise portion of the mission was 

flown at only 5,000 feet, an altitude where the 

R-4360 piston engines and big propellers were 

operating at maximum efficiency; the airplane 

could climb to 5,000 feet in 14 miles and the 

cruise speed during this portion of the mission 

was only 279 mph.88
The crew of a Convair B-36F (49-2669) pose in their 

partial-pressure suits before a test flight. When the suit was 

not inflated, it was relatively comfortable and allowed 

adequate mobility, as shown by the men kneeling. It was an 

adequate get-me-down garment in case of a major problem 

aboard the bomber.

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

144

The MC-1 suit was developed specifically to replace the 

S-2 in the Featherweight versions of the Convair B-36 intercontinental bomber. Because of the long missions flown by the 

bombers, comfort was a primary driver in the development 

of this suit. Ultimately, researchers concluded the suit did not 

provide adequate protection and it was replaced in service by 

the MC-3. However, by that time, the B-36s were long gone.

U.S. Air Force photo. 

Courtesy of the Terry Panapolis Collection

After flying for approximately 3,000 miles, 

the B-36 would begin climbing to its 

45,000-foot combat altitude. It would take 

almost 2 hours and a little over 550 miles 

to climb from 5,000 feet to 45,000 feet, 

and the airplane would reach its combat 

altitude approximately 500 miles from the 

target. Fuel was budgeted to fly at maximum 

continuous power for 15 minutes before 

reaching the target and 10 minutes after 

weapons release; this equated to 425 mph 

and covered just over 175 miles.89

Reconnaissance versions of the B-36 flew 

somewhat higher and farther, and the Eighth 

Air Force stated that 45–60 minutes were 

normally required to descend from 53,000 to 

40,000 feet and that 25 minutes was probably the quickest the airplane could descend. 

The Eighth Air Force appeared to believe that 

the existing S-2 suit might provide adequate 

protection for the 3-hour period, but physiologists doubted that an airman could remain at 

extreme altitude for the full period because of 

the discomfort and inconvenience of the suit.90

Toward the end of 1953, the SAC announced 

a firm requirement for a continuous-wear 

partial-pressure suit capable of protecting crewmembers at 50,000 feet. Furthermore, by late 

1954 they would need a suit capable of operating at 55,000 feet and by 1960, one capable 

of sustaining crewmembers at 60,000 feet. 

In response, the Aero Medical Laboratory and 

David Clark Company began the development 

of the MC-1 Featherweight suit.

In many ways, the MC-1 was a step back to 

the original David Clark Company versions 

of the Henry Suit. The MC-1 added breathing 

bladders to the chest and abdominal torso sections to reduce the work of breathing. When 

the airman in-haled, the bladder deflated, 

leaving room for his lungs to expand in the 

tight suit. When he exhaled, the bladder 

reinflated and put pressure on his chest and 

abdomen, aiding the process. Even though a 

flyer wore long underwear under the S-2/T-1 

suit, he was subject to skin pinches when the 

capstan tubes expanded. To help alleviate the 

discomfort, the MC-1 contained antipinch 

bladders and used smaller arm and shoulder 

capstans. The new suit was also equipped with 

bladders in the upper arms that bled into pressurized gloves. The MC-1 used either the K-1 

or the MB-5 helmet. Like the S-2 and T-1, 

the suit was available in the 12 standard sizes, 

plus custom-fitted versions manufactured by 

Berger Brothers. By January 1955, the first of 

1,200 MC-1 suits were available.

There was a curious issue with the initial 

deliveries of the MC-1 suit. In many 

instances, crewmembers discovered the 

sleeves were too short, even though they 

were identical in length to those on the 

T-1 and S-2. It soon became apparent that 

the discrepancy stemmed from the use of 

gloves with the MC-1. Pressurized gloves 

were not worn with the T-1 or S-2 suits, so 

sleeve length had not been a particular issue. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

145

With the MC-1, the sleeve had to connect 

with an inflation tube on the gloves, and 

any shortage of length caused the gloves 

to separate from the sleeve. David Clark 

Company quickly, and simply, corrected the 

situation by adding an individually fitted 

length of tubing from the sleeves to the gloves.

As it did with all the early pressure suits, the 

Guardite Strato Chamber at Wright Field 

played a key role in the development of the 

MC-1 suit. For instance, during May 1954, 

two test subjects wore suits at 55,000 feet 

for 4 hours and two others at 50,000 feet 

for 6 hours. By the end of July 1955, 17 chamber runs at 50,000 feet had lasted from 

1 to 7 hours, and 9 runs at 55,000 feet lasted 

between 30 minutes and 4 hours. Three 

runs at 60,000 feet lasted from 1 to 3 hours. 

Researchers also completed seven runs at 

65,000 feet, ranging from 12 minutes to 

almost 2 hours. Finally, subjects completed two 

runs above 80,000 feet, with exposure times 

above 50,000 feet in excess of 45 minutes.

These experiments created a tremendous 

demand for men to make the chamber runs. 

The Aero Medical Laboratory found it was 

not desirable to continually use the same test 

subjects. So, in addition to persons connected 

with the project (many of whom made chamber runs repeatedly), the laboratory obtained 

pilots from other units as subjects. To its 

credit, the laboratory did not attempt to make 

these experiments appear glamorous. For 

example, an advertisement for a test in 1954 

announced, “This will require an attempted 

11 hour stay at altitudes above 45,000 feet, 

plus a 2 hour preoxygenation period. Thus an 

‘all-day’ (14–15 hours) experiment is anticipated. In addition, various types of instrumentation will be used, all of which help produce 

a very long and miserable day.”91 Just what 

one wanted to do on his day off.

Perhaps not unexpectedly, the “volunteers” 

generally were not motivated to endure the 

inconvenience and discomfort nor the actual 

pain that occurred in a certain percentage 

of subjects during chamber runs. There was 

some thought of providing a “graded monetary motivation system” under which subjects 

would be paid for each hour spent at altitude, 

but the plan was never put into use since Air 

Force Headquarters disapproved the request 

for funds.92 In its search for subjects to make 

chamber runs with the Featherweight suit during early 1954, the laboratory came up with 

the idea of killing two birds with one stone: 

indoctrinate the B-36 crews in the use of altitude suits while using them for chamber tests. 

Although an interesting concept, the timing 

never worked and no operational crew participated in the development tests.

Despite the advancements over the previous S-2 suit, some felt the MC-1 did not 

provide adequate protection. An in-depth 

physiological evaluation of the MC-1 was 

prompted in early 1954 when Air Force 

Headquarters began considering the development of a “mission-completion” garment. 

Ultimately, this evaluation demonstrated the 

ineffectiveness of the MC-1 and led, along 

with other drivers, to the development of the 

MC-3 partial-pressure suit.93

The evaluation by the Aero Medical 

Laboratory concluded that the “MC-1 

partial-pressure ensemble (MC-1 suit, K-1 

or MB-5 helmet, and pressure gloves) clearly 

demonstrated its gross inadequacy to meet 

the stated USAF maximum time-altitude 

requirements.”94 The study found that the 

probability of three crewmembers being 

functional at an altitude of 60,000 feet after 

1 hour was only about 1 in 7. In most cases, 

the altitude chamber runs were terminated 

because of an impending syncope that implied 

a fainting reaction. Symptoms included pallor, 

nausea, sweating, weakness, malaise, and a 

sensation of “being overwhelmed.”95 The 

researchers found that at 60,000 feet, there 

was usually only about a minute’s warning 

before a subject fainted.

The MC-1 had only small anterior chest 

and abdomen bladders that did not offer 

adequate counter-pressurize on the outside 

of the chest to equalize the high intrathoracic 

pressure present during pressure breathing. 

When the average wearer was subjected to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

146

65,000 feet for 1 hour, remarkable physiological changes occurred.96

The most important physiologic response 

was the alarming frequency of sudden 

presyncope (lowering of blood pressure). 

The pattern leading up to syncope was 

fairly uniform. The subject was exposed to 

65,000 feet when he suddenly broke into 

moderate diaphoresis (sweat) over his entire 

body, easily discernable on the arms and legs, 

where the sweat evaporated through permeable fabric, creating a cold sensation. Concomitantly, there was a definite hypotension 

and a relative bradycardia in which the pulse 

dropped from 160 to 75 beats per minute. 

(True bradycardia implies that the pulse is 

below 60 beats per minute.) With the sudden hypotension and bradycardia, researchers 

inferred that there was a dramatic decrease 

in cardiac output.97

The time from the first symptom until 

syncope varied from a few seconds to 2 minutes. Researchers always tried to terminate 

the test before unconsciousness but were often 

unable to do so because of the rapid onset of 

symptoms. When this occurred, the chamber 

was depressurized from 65,000 to 40,000 feet 

in about 5 seconds. The subject normally 

returned to consciousness in 4–6 seconds, 

although pallor, clammy skin, hypotension, 

and bradycardia often lasted for a couple 

of hours.98

The reactions varied widely based on the 

individual. Researchers found the ability of 

crewmembers to remain at 65,000 feet in 

the MC-1 ensemble ranged from 2 minutes 

to more than 2 hours. Not surprisingly, the 

researchers, largely, could determine which 

crewmembers would tolerate the tests well 

and which would not. Physical fitness and 

medical condition obviously played a role, 

but the researchers also found that “the aggressive independent individual performs much 

better than the more submissive type.”99

Nevertheless, something better than the MC-1 

suit was clearly needed.

MB-1 AND MB-2—ILL-FATED AIR 

DEFENSE COMMAND SUITS

During the development of the S-2 and T-1 

suits, which were designed to offer shortterm protection up to 65,000 feet, the Aero 

Medical Laboratory obtained a great deal of 

background data at lower altitudes. These data 

disclosed that, from a mechanical stand-point, 

development problems increased tremendously above 55,000 feet. In January 1953, 

the laboratory proposed to develop a garment 

that would be limited to a maximum altitude 

of 55,000 feet and a maximum pressurized 

time of 6 minutes. It was expected to provide 

greater comfort and mobility than the S-2, 

since only those areas of the body most vital 

to circulation, such as the legs, abdomen, 

and chest regions, would be pressurized. 

Because the suit would eliminate the capstans 

on the arms and shoulders, arm mobility 

would be unhampered even when the suit 

was pressurized. The suit would also be less 

expensive to procure and maintain than the 

S-2. The laboratory assigned the development 

to the David Clark Company.100

The new suit was intended primarily to 

meet the requirements of the Air Defense 

Command (ADC) and a new generation 

of interceptors. The concept of dedicated 

interceptors had come to fruition during 

World War II—the Messerschmitt Me 163 

being an early example of an aircraft intended 

solely to shoot down enemy bombers over its 

home territory. After the war, it seemed that 

all things became more specialized, furthering 

the concept of dedicated interceptors. This 

was helped in the U.S. Air Force by the fact 

that there were two operating commands: 

the ADC and the Tactical Air Command 

(TAC). Each wanted its “own” aircraft, and 

so defensive interceptors and tactical fighters 

began to diverge in design and capabilities. 

Following the end of the war in Europe, 

relations between the United States and the 

Soviet Union rapidly deteriorated. However, 

at that time, there seemed to be little 

direct threat from the Soviet Union to the 

continental United States itself. This changed 

in October 1947, when several Tupolev Tu-4 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

147

heavy bombers (reverse-engineered B-29s) 

appeared at the Tushino air display, and the 

newly organized U.S. Air Force was now faced 

with a potential strategic bombing threat from 

the Soviet Union.

In early 1949, the Air Force issued a request 

for proposals for a supersonic interceptor to 

replace the Northrop F-89 Scorpion that was 

just entering development. This program 

came to be known as the “1954 Interceptor,” after the year that the new aircraft was 

expected to enter operational service.101 

This aircraft would become the Convair 

F-102 Delta Dagger, a delta-wing interceptor capable of exceeding the speed of sound. 

The ADC would also operate variants of the 

McDonnell F-101 Voodoo and Lockheed 

F-104 Starfighter before it received its 

“Ultimate Interceptor,” the delta wing 

Convair F-106 Delta Dart.

The MB-1 partial-pressure suit followed 

the coverall pattern of its predecessors and 

contained abdominal and chest bladders 

with smaller capstans on the thighs and 

calves. Unlike all earlier partial-pressure suits, 

the arms and shoulders were unprotected. 

The initial flight tests took place in September 

1954 when five pilots from the Air Research 

and Development Command used the 

MB-1 on 25 flights with mixed results. Further testing by Air Defense Command pilots 

showed the suit was unsatisfactory. At a 

conference held on November 9–10, 1954, 

the Aero Medical Laboratory discontinued 

development of the MB-1, and the 

Air Defense Command adopted the S-2 

as its standard partial-pressure suit.102

A similar MB-2 suit incorporated 

G-protection for use by experimental 

test pilots, but the USAF cancelled it at 

the same time as the MB-1.

MC-3 AND MC-4—DRAGON LADIES 

AND HUSTLERS 

In 1954, while David Clark Company was 

developing the MC-1, the Aero Medical 

Laboratory felt that the SAC would need 

further improved suits to meet the coming 

requirements for the Boeing B-52 Stratofortress and Convair B-58 Hustler bombers. 

The B-52 requirement, stated in December 1953, specified protection for 3 hours 

above 50,000 feet and for 11 hours above 

46,500 feet. The B-58 requirements called for 

1 hour between 54,000 and 70,000 feet and 

8 hours above 52,000 feet. The laboratory 

believed that modifications to the basic MC-1 

could meet these requirements and be available in time to support initial operations. The 

MC-1 suit as finally developed gave no time 

limit for protection to 50,000 feet and up to 

105 minutes at 65,000 feet. Nevertheless, it 

The Convair F-106 Delta 

Dart was the Air Defense 

Command’s (ADC) primary 

interceptor for several 

decades and was capable of 

zoom climbs above 60,000 

feet. Because of this, the 

ADC evaluated any number 

of full-pressure suits for the 

airplane, but ultimately it 

was usually flown without 

any type of pressure suit. 

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

148

was uncomfortable and lacked mobility. By 

the end of 1955, the Aero Medical Laboratory 

was examining a number of other possibilities, 

including a new partial-pressure suit and a 

full-pressure suit, to meet the needs of the 

B-52 and B-58.103

Although the laboratory, and David Clark 

Company, did not know it at the time, the 

primary impetus for a new suit would come 

from a completely different, and unexpected, 

source. In early 1954, two USAF officers vis-

ited the David Clark Company for a security 

inspection. Given that the company had oper-

ated classified projects for over a decade, this 

raised some eyebrows, but no explanation was 

immediately forthcoming. A short while later, 

the company was asked to send technically 

knowledgeable representatives to a meeting in 

Washington. David Clark, John Flagg, and Joe 

Ruseckas made the trip. The men were told 

that a new aircraft was being developed that 

would fly higher than 70,000 feet and that a 

partial-pressure suit was necessary for the proj-

ect. The Government would not disclose what 

the airplane was, what it was intended to do, 

or what company was developing it.104

However, the Government did disclose the 

need for a partial-pressure suit comfortable 

enough to be worn for 12 hours unpressur-

ized and as long as 4 hours pressurized. David 

Clark said that, given recent guidance from the 

Anthropometry Department at Wright Field, 

A new generation of jet 

bombers, such as the Boeing 

B-52 Stratofortress (top) 

and Convair B-58 Hustler 

drove requirements for 

improved pressure suits that 

could be worn comfortably 

for long periods while operating sophisticated weapons 

systems. Eventually the 

Air Force decided that 

neither the B-52 nor B-58 

required a pressure suit. 

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

149

it was impossible to manufacture such a suit. 

The Air Force intended to fit all pilots with a 

limited number of suit sizes, and this resulted 

in somewhat less comfortable suits than could 

otherwise be manufactured. The representatives from the new project were not interested 

in minimizing the number of suit sizes, and 

they told David Clark to create custom-fitted 

suits that were as comfortable as possible. The 

pilots would be made available in Worcester, 

where David Clark Company would measure 

them and fit them for their suits.105 It was the 

beginning of David Clark Company’s involvement in the most significant series of reconnaissance aircraft ever developed.

During World War II, modified combat 

types—P-38s, P-51s, and B-29s equipped 

with cameras—conducted most aerial 

reconnaissance. Toward the end of the war, 

recognizing the need for more dedicated 

platforms, the Army initiated the development 

of the Hughes XF-11 and Republic XF-12 

Rainbow. Neither aircraft entered production, 

but they demonstrated the substantial increase 

in capabilities available in designs tailored for 

the mission. The decrease in defense spending 

following the end of the war, however, meant 

that combat types would continue to be used 

for reconnaissance. The Air Force pressed 

modified B-36, B-45, and B-50 bombers, 

as well as a variety of fighters, into service as 

reconnaissance aircraft.106

By 1952, thoughts again turned to a dedicated 

high-altitude platform, and in March 1953, 

the Air Force released a formal specification 

to three small aircraft manufacturers. Each of 

the companies—Bell, Fairchild, and Martin—

received 6-month $200,000 study contracts 

on July 1, 1953, as part of Project MX-2147 

under the codename Bald Eagle. Only 

Bell and Fairchild were asked to design new 

aircraft to meet the specification. Martin was 

tasked instead with designing a modification 

to its B-57 Canberra, which had originally 

been designed in the United Kingdom by the 

English Electric Company. 

By the middle of 1954, the Air Force decided 

the Martin RB-57D would be procured as an 

interim platform pending the development 

of the Bell Model 67 hidden behind the X-16 

During and immediately after World War II, the Air Force 

commonly used converted combat aircraft for reconnaissance 

missions. For most of the early 1950s, the premiere long-range 

reconnaissance aircraft was the Convair RB-36. These aircraft 

routinely flew in excess of 50,000 feet and carried a wide 

variety of camera and electronic ferret equipment, but as far 

as is known, they never ventured over the Soviet Union. 

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

150

designation. Fairchild’s proposal was never in 

serious contention due to its unconventional 

configuration. The competition was disrupted, 

however, on May 18, 1954 when the Air 

Force received an unsolicited proposal from 

Kelly Johnson at Lockheed. The Air Force 

conducted a thorough, if somewhat hurried, 

review, and on June 7, notified Johnson that 

his proposal had been rejected. 

Hardly deterred, Johnson decided to pursue 

funding through other channels. In this case, 

“other channels” meant the Central Intelligence Agency (CIA), which had discovered 

that the military could not be depended upon 

to provide detailed reconnaissance whenever 

and wherever the CIA wanted it. Since the 

Soviet Union was embarking on a program to 

develop and field long-range missiles equipped 

with nuclear warheads, the CIA considered 

on-demand intelligence critical. The obvious 

answer was to create a private air arm, and on 

November 19, 1954, Johnson discussed the 

modified design with the intelligence community. The proposal generated a great deal of 

interest, assuming Lockheed could deliver the 

aircraft quickly.

Johnson promised the first aircraft would fly 

by September 1955, less than a year in the 

future. At the end of November, the CIA 

formally approved the project under the codename Aquatone. The CIA awarded Lockheed 

a $54 million contract for 20 production 

aircraft on December 9, 1954, although Johnson later returned almost $8 million of this 

due to cost underruns. By the end of 1954, 

Johnson and his team of 25 engineers and 

81 shop personnel began working 100-hour 

weeks to meet the schedule. While Johnson 

did eventually get additional personnel, he 

never had more than 80 engineers working on 

the U-2 project.

The design was technologically demanding 

since minimum weight and drag were essential. On December 10, 1 day after the contract 

was signed, the Aquatone design was frozen. 

Ten days later, Lockheed began construction 

of production tooling. Around this time, the 

aircraft became known within Skunk Works as 

“Kelly’s Angel” or simply as Angel. The CIA 

assigned a second code name to the project: 

Idealist. The individual aircraft were known 

as “articles.” 

Midmorning on July 24, 1955, the first 

U-2A (Article 341) arrived at Groom Lake, 

better known to Lockheed personnel at the 

time as the “Test Location” or simply “The 

Ranch.” The subject of much speculation and 

many rumors over the years, Groom Lake is 

located inside a restricted area (Area 51) near 

the nuclear test site run by the Department 

of Energy (originally, the Atomic Energy 

Commission). It is located approximately 

100 miles northwest of Las Vegas, NV.

The Lockheed U-2 looked 

more like a glider than a spy 

plane but proved to be an 

irreplaceable resource. The 

airplane was extremely tricky 

to fly, and pilot fatigue on 

long missions was always a 

concern before the invention 

of reliable autopilots. 

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

151

The U-2 was an unusual aircraft, looking more 

like a glider than any preconceived vision of 

a spyplane. The fuselage was 49.66 feet long 

and the wings spanned 80.10 feet. There was 

a decided lack of stringers and other forms of 

stiffening, and the skin was only 0.02 inch 

thick in places. The unusual construction 

was indicative of the extreme measures taken 

to lighten the airframe. This led directly to 

extremely low maneuvering limits—only 

+1.8/–0.8-G under some flight conditions, 

and never more than +2.5/–1.0-G under 

any conditions. Compare this to the normal 

USAF standard of +7.33/–5.0-G for fighter 

aircraft of the era.

The cockpit was small and cramped with a 

single large control wheel similar to that found 

in most transport aircraft. The instrument 

panel was largely conventional except for the 

inclusion of a 6-inch hooded drift-sight/sextant. The effort to save weight resulted in not 

providing an ejection seat and even the deletion of explosive bolts to jettison the canopy. 

If the pilot needed to bail out, he would have 

to manually detach the canopy prior to leaving the aircraft. This omission later proved 

fatal and Lockheed corrected it by installing 

a simple ejection seat.

Static engine runups were conducted on 

July 27, and the first taxi test came on 

July 29, 1955, by former air racer and 

Lockheed test pilot Anthony W. “Tony” 

LeVier. During the second taxi test, the aircraft climbed to an altitude of approximately 

35 feet before LeVier could adjust to the 

flat featureless desert and determine that 

he had actually left the ground. After some 

consternation, LeVier managed to get the 

aircraft back on the ground, although the 

brakes caught fire and had to be rebuilt. The 

first intentional flight came on August 4, 1955, 

with LeVier again at the controls. Four days 

later, on August 8, LeVier made the “official” 

first flight in front of senior CIA officials.

The U-2 had some peculiar flight characteristics at altitude. The most worrisome was that 

the stall speed and never-to-exceed speed could 

be separated by as little as 10 knots. In fact, if a 

pilot turned too sharply, the inside wing could 

be in “stall buffet” (going too slowly) while the 

outside wing could be in “Mach buffet” (too 

fast). Recovery from a stall (too slow) could be 

difficult since elevator authority was limited, 

while exceeding the maximum permissible 

speed by as little as 4 knots could result in the 

aircraft breaking up. To assist the pilots, Lockheed provided a fairly effective autopilot, but it 

was still incumbent on the pilot to ensure the 

aircraft was in the proper speed regime. Luckily, as fuel was burned the margin for error 

increased, so as a pilot tired on a long flight he 

actually had more latitude for mistakes.

Early jet engines were not known to be 

overly reliable, and those modified to operate 

in the rarified air above 60,000 feet were 

notably temperamental. Flameouts were 

a frequent occurrence during the early 

flight-test program. This was not a pleasant 

event at 65,000 feet, since the U-2 had to 

descend below 35,000 feet to effect an air 

start. Luckily, the U-2 could glide more than 

275 miles, taking some 73 minutes to do so.

Two different cover stories emerged to explain 

the existence of the U-2. Unbelievably, the 

first indicated that the U-2 (and it was always 

referred to as a singular entity) was a test vehicle to examine certain flight characteristics relative to the F-104 program. The second story 

was that the NACA used the aircraft for high 

altitude atmospheric and weather research. In 

fact, when the U-2 was first unveiled to the 

public, it carried fictitious NACA markings, 

something that was repeated many times over 

the early years of the program.

The deception, reluctantly agreed to by the 

Director of the NACA, Hugh L. Dryden, was 

not completely untrue. The cover story was 

that the aircraft were being used to collect 

information on the jet stream, cosmic ray particles, and ozone and, in fact, most early U-2 

training flights around the world did carry 

NACA instruments. The data was turned over 

to the NACA for evaluation, but the pilots 

were always CIA cum Lockheed, and the 

NACA had no say in where or when the data 

was collected. Eventually, the original U-2s 
The U-2 used an unusual landing gear configuration 

with two main gear in the fuselage and outrigger gear 

under each wing that fell off as the airplane took off. 

As the airplane slowed down after landing, one wingtip 

would drag on the ground until a ground crew replaced 

the outriggers.

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

153

would be flown by the CIA, the U.S. Air Force, 

the Republic of China Air Force (Taiwan), 

and, ironically, the National Aeronautics and 

Space Administration (NASA). These airplanes 

would serve until they were finally retired 

in 1989, replaced by a larger variant called 

the U-2R.107

Because of the extreme altitudes promised 

by the U-2, the CIA knew the pilots would 

need pressure suits. Never being bashful about 

seeking the best advice, the CIA approached 

Col. Donald D. Flickinger (1907–1997), the 

chief of human factors at the Air Research 

and Development Command. The doctor 

had a fascinating career. During World War II, 

Flickinger had been the flight surgeon for the 

Air Transport Command in the China-BurmaIndia (CBI) Theater. But he was a flight surgeon like no other and frequently parachuted 

into the dense jungle to rescue downed aircrews. His most famous rescue came on 

August 2, 1943, when a Curtiss C-46 Commando transport crashed near the Chinese 

border. Of the 21 crew and passengers—

including newsman Eric Sevareid—only the 

copilot perished. Flickinger and two other 

medics parachuted into a clearing where the 

survivors were camped, and a month later, 

they walked out of the jungle, little the worse 

for the experience.108

Flickinger received his M.D. from the 

Stanford Medical School and took 

post-graduate training at Vanderbilt and 

Harvard before joining the Army in 1937. 

He received training as a flight surgeon at the 

School of Aviation Medicine and reported 

to the 19th Bomb Group. Flickinger was the 

medical officer of the day at Pearl Harbor 

when the Japanese attacked and spent 72 hours 

straight helping wounded servicemen. After his 

service in the CBI Theater, Flickinger became 

the director of research at the USAF School of 

Aviation Medicine, and in 1951, he became 

the first director of human factors for the Air 

Research and Development Command. In 

August 1955, he became the first commander 

of the Air Force Office of Scientific Research. 

His specialty was high-altitude survival and 

bailout, and Flickinger helped with oxygen 

systems, parachutes, and pressure suits. 

Flickinger went on to work with the Lovelace 

Clinic in Albuquerque, NM, screening the 

original Mercury astronauts. Left unsaid 

in most biographies and obituaries was the 

extraordinary service he performed for the 

U-2 and subsequent A-12 program.

During the 1954 meeting in Washington, 

Flickinger discussed the medical requirements 

for pilot protection with David Clark, John 

Flagg, and Joe Ruseckas. When they returned 

to Worcester, Ruseckas got to work developing the patterns for a new partial-pressure suit 

while Flagg attended to the myriad of other 

details involved with developing a new product. At the time, the David Clark Company 

had only a handful of people involved in 

the pressure-suit business. Besides Flagg and 

Ruseckas, there were a half-dozen designers 

and pattern makers and a handful of seamstresses working at the company’s facility on 

Park Avenue in Worcester.109

Eventually, David Clark Company learned 

that the new project was the CIA U-2. Unlike 

most USAF aircraft that generally had the 

option of descending to a lower altitude and 

landing if a problem occurred, the U-2 did 

not have that luxury; the Soviets would not be 

amused to find the airplane over their territory. 

Therefore, the new partial-pressure suit had to 

be comfortable enough to allow the pilot to 

control his airplane while wearing it for prolonged periods. Because of its small cockpit, 

early model U-2s continued to fly with partialpressure suits until the end of their careers.

During early 1956, the first six CIA pilots 

arrived at Groom Lake as part of Operation 

Overflight. These were active duty 

military pilots who had been “sanitized” by 

the CIA—their names and backgrounds were 

fictitious, and officially, they were employed 

by Lockheed, although their pay came from 

CIA funds. Each would travel twice to 

Worcester to be fitted for their new partialpressure suits. During the first trip, each pilot 

was carefully measured so that Joe Ruseckas 

could tailor the generic pattern for a comfortable fit. After the suit was completed, the pilot 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

154

would return for a fitting and any needed 

alterations. After everybody was satisfied the 

suit was tailored correctly, the pilot would 

head to Buffalo, NY, to try the suit in the altitude chamber at Firewel Corporation, often 

flown there in David Clark’s personal airplane 

by Joe Ruseckas. 

Two alumni of Scott Aviation, Philip Edward 

“Ed” Meidenbauer, Jr. and Donald Nesbitt, 

founded Firewel Corporation in 1946. 

Meidenbauer, a self-taught mechanical engineer, had been director of oxygen research 

at Scott Aviation, where he developed the 

original Scott Air-Pak. His brother, Clifford 

Meidenbauer, a Signals Corp officer during 

World War II, soon joined the company as 

the financial officer.110

Operating from the basement of Meidenbauer’s 

house, the company began building burners to 

convert old coal furnaces to oil or gas. By 1947, 

the company had advanced from conversions 

to a full line of manufactured furnaces. 

Looking to expand its business, the company 

soon received an $80,000 Army contract for 

an oxygen regulator. In 1951, David Clark 

contacted Ed Meidenbauer about supplying 

a regulator for the full-pressure suit David 

Clark Company was developing for the Navy. 

Firewel soon became the primary supplier of 

suit controllers and oxygen regulators to both 

David Clark Company and B.F. Goodrich. 

By 1956, Firewel employed 140 people and 

was a multi-million-dollar corporation. Two 

years later, the founders sold the company to 

ARO Equipment Company. In 1985, Todd 

Shipyards bought the business from ARO, and 

Ingersoll Rand took over the group in 1990.111

Former Firewel employee John Carleton 

Goodell, along with George Ord, founded 

Carleton Aviation in 1955 and bought the 

aerospace part of ARO in 1993. Since then 

the company has progressed to become Carleton Technologies Inc., a wholly owned subsidiary of Cobham plc, located in Wimborne, 

Dorset, England. Cobham is a consortium of 

companies supplying products and services to 

the aerospace and defense industries. Carleton 

continues to produce equipment for high altitude and space flight.112

During the 1954 tests of the MC-1 suit by 

the Aero Medical Laboratory, Capt. Terence 

F. McGuire modified an MC-1 suit with a 

double-layer, airtight lining from the neck 

to mid-thigh. The neck seal was extended 

down under the edge of the suit bladder system, then inverted to cover the neck. These 

modifications, along with an early MA-2 

helmet, provided full-pressure coverage from 

the top of the head to mid-thigh, leaving only 

the extremities under partial pressure. Since 

the arms and legs “are of tubular form,”113

McGuire thought that the mechanical capstan 

system was sufficient. The capstans were also 

left across the shoulders and back, although 

they were normally overridden by the bladder 

system. If the torso bladder failed, the capstans 

could provide the equivalent of a T-1 suit and 

suffice as a get-me-down garment.

Volunteers tested McGuire’s suit as high 

as 198,770 feet, which is almost a perfect 

vacuum, with only one three-thousandths 

of an atmosphere. Some subjects that had 

performed very poorly using the MC-1 suits 

were able to remain at 100,000 feet for several 

hours. This data proved valuable as the design 

of the new U-2 suit progressed. The suit that 

David Clark Company developed was a cross 

between the original S-2 and the modified 

MC-1 and is often called an S-3 suit, although 

that appears to be unofficial at best and incorrect at worst. Initially, the USAF called the 

suit X-91, probably as part of the secrecy surrounding the U-2 program, but ultimately 

designated it MC-3.114

Martin A. “Marty” Knutson was the first operational U-2 pilot to be fitted for a pressure 

suit. He was “Number 16,” the first 15 having 

been test pilots. Kutson’s career in aviation 

began in 1950 as an Air Force aviation cadet. 

Following service in Korea flying F-84s, he 

joined the CIA pilots getting ready to deploy 

the U-2. He retired from the USAF in 1970 

with over 6,500 hours of flight time, much 

of it flying over the Soviet Union and Eastern 

Europe in U-2s. The following year Knutson 

joined NASA at the Ames Research Center 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

155

and later as the Director of Flight Operations 

at the Dryden Flight Research Center. Near 

the end of his NASA career, he was instrumental in getting the USAF to transfer three 

SR-71s to NASA instead of retiring them.115

The MC-3 was a substantial improvement over 

earlier suits and represented a turning point 

between capstan (mechanical) and bladder 

partial-pressure suits. Like its immediate predecessors, the MC-3 used capstans to provide 

counter-pressure on the limbs, but it was fitted with a full-torso bladder extending from 

the shoulders to mid-thigh, completely surrounding the chest, abdomen, hips, and upper 

thighs, and passing through the crotch (the 

MC-1 had only chest and abdominal bladders). These bladders inflated and deflated with 

the breathing of the wearer.116 The leads to the 

torso bladder and capstans were an extension 

of the bladder system instead of being separate 

hoses as in all earlier suits. Additional lacing, 

extending up the inner thigh, the small of the 

back, and down the chest, provided better control of the torso bladder and more variation in 

circumferential fit. A horizontal shoulder zipper made the new suit easier to don and doff. 

Zippers were also located at the ankle, wrist, 

and back placket, and a new chest zipper ran 

from the waist to the neck. The buttock zipper was eliminated, but a shortened front fly 

zipper was retained. Break lines—cords sewn 

into heavy seams to “break” the continuity of 

a bladder when inflated—were located at the 

waist and groin to make it easier to bend and 

sit. The MC-3 used the MA-2 helmet, manufactured by ILC Dover.117

The initial pilots tested their suits in the 

Wright Field altitude chamber at 65,000 feet 

for 4 hours with no major complaints. After 

the tests, Col. Philip Maher, the USAF liaison 

on the project, asked David Clark if the company could improve the MA-2 helmet. The 

pilots were complaining that it was difficult to 

turn their heads, mostly because the restraint 

fabric connecting the helmet to the suit was 

stiff and did not move under pressure. This 

became the first use for a new “Link-Net” 

fabric that David Clark developed for the 

neck section to allow the pilot to turn his head 

more easily. At first, the USAF sent helmets to 

Worcester for David Clark Company to add 

the Link-Net, but eventually David Clark sold 

preformed Link-Net sections to ILC Dover, 

which extended the modification to all pressure suit helmets.118

In January 1956, the Tactical Air Command 

issued requirements for a “mission completion suit” for the Martin B/RB-57 Canberra 

and Douglas B/RB-66 Destroyer to replace 

the MC-1 suits the command had intended 

to use. Exactly why TAC was so concerned 

about providing pressure suits for these light 

bombers is unclear since neither had an operational ceiling much above 40,000 feet, and 

seldom operated anywhere near that altitude. 

An early MC-3 suit being readied for a U-2 flight from 

Watertown, otherwise known as the CIA test facility at 

Groom Lake, NV. This photo shows the interdigitizing laces 

along the arms and legs to good advantage. The capstan tubes 

were sewn in such a way that as they inflated, they pulled 

the laces tight, providing surface pressure against the skin 

of the wearer. In addition to the capstans, the MC-3 used a 

full-torso bladder, extending from the shoulders to mid-thigh, 

completely surrounding the chest, abdomen, hips, upper 

thighs, and passing through the crotch (the MC-1 had only 

chest and abdominal bladders). The chest bladder also acted 

as breathing vest. 

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

156

Francis Gary Powers wearing an MC-3 partial-pressure 

suit and MC-2 helmet in front of a Lockheed U-2A. The 

MC-3 had additional lacing, extending up the inner 

thigh, the small of the back, and down the chest, to provide 

better control of the torso bladder and more variation 

in circumferential fit. Powers was shot down over the 

Soviet Union on May 1, 1960, and was not returned to 

the United States until February 10, 1962, in an exchange 

for Soviet KGB Colonel Vilyam Genrikhovich Fisher (aka 

Rudolf Abel), a Soviet colonel who was caught by the FBI. 

Courtesy of Lockheed Martin Aeronautics

Interestingly, by this time, the SAC had 

decided the B-52 and B-58 would have “shirtsleeve” environments and that pressure suits 

were not required. Nevertheless, some flights, 

especially early flights in B-58s before the 

installation of the ejection capsules, used 

MC-1 or MC-3 partial-pressure suits.119

Things took an unexpected turn on February 7, 

1956, when Lt. Gen. Thomas S. Power, commander of the Air Research and Development 

Command, informed attendees at a personal 

equipment conference in Baltimore that a new 

“partial-full” pressure suit, “developed for a 

special application,” had proven so successful 

that it would immediately replace all existing 

partial-pressure suits. The USAF considered 

these “mission completion” suits (as opposed 

to get-me-down suits), and the military 

expected to use them to “stay up” for up to 

4 hours, if needed.120

On March 6, 1956, within weeks of Air 

Force Headquarters selecting the MC-3 for 

immediate operational use, the Air Materiel 

Command began negotiating procurement 

contracts. The USAF set aside $7.4 million 

to purchase MC-3 suits for the B-57, B-66, 

F-100, F-101, and F-102 aircraft assigned 

to the TAC and ADC.121 Ultimately, Berger 

Brothers and David Clark Company manufactured the suit, which was available in the 

12 standard sizes, plus custom sizes (this time 

by David Clark Company) as needed for 

U-2 pilots. The special sizes were particularly 

necessary for the 30 Republic of China Air 

Force pilots that arrived at Groom Lake to 

the fly the U-2.122

In the meantime, the USAF cancelled contracts for all other partial-pressure suits and 

directed that existing stocks of S-2, T-1, T-1A, 

and MC-1 suits be used only for ground training. Somewhat belatedly, the USAF realized 

that cancelling the procurement of all existing 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

157

The MC-3 was often worn with an outer layer to cover the 

capstans and laces to ensure they did not get tangled with 

switches or other objects in the small cockpit of the U-2. The 

outer covers came in a variety of colors or in this instance, 

multicolors. This outer cover was used over friendly territory 

to aid searchers in the event the pilot had to eject; solid sagegreen covers were used on the clandestine missions. 

Courtesy of Lockheed Martin Aeronautics

suits had been too drastic. Although they were 

far from perfect, the suits were dependable and 

much better than no protection at all. Phasing 

in the new MC-3 suit would undoubtedly be 

a gradual process, so the USAF reinstated contracts for 1,500 T-1A suits.

There were a wide variety of MC-3 configurations, including those with the hose connections on the left (S621L) or on the right 

(S621R), those with different helmet holddown configurations (S621LM), and those 

without the back capstan (S621AR). As 

it ended up, David Clark Company only 

manufactured 1,073 MC-3 suits (884 Model 

S616 and 189 Model S621) before production switched to the MC-3A (S687 and S799) 

in 1958.123

The MC-4 (BB-MC-4 and S805) began life 

as an MC-3 with an integral G-suit. However, 

the designers took the opportunity to again 

reconfigure the suit closures to increase 

comfort and mobility, primarily by deleting 

the shoulder zipper in favor of more lacing. 

As was the case in all of the partial-pressure 

suits, the G-suit operated more efficiently 

when the partial-pressure suit bladders were 

already inflated.124

Before the MC-4 was developed, the Navy 

ordered modified MC-3s that allowed the 

pilot to reach the face-curtain ejection 

handle and provided the same acceleration 

protection as the C-1A G-suit. These were 

designated C-4 (S759). After the MC-4 

entered production the Navy ordered 

modified versions as the C-4A (S785).125

The MC-3A was identical to the MC-4 without the G-suit, including the vertical shoulder 

lacing and adjustable break lines. The MC-3A 

again used the MA-2 helmet although most 

MC-3 and MC-4 suits were eventually modified so they could use ILC Dover MA-2, Bill 

Jack MA-3, or MB-5 helmets. Both Berger 

Brothers and David Clark Company manufactured MC-3A suits (BB-MC-3A and S687, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

158

The MA-2 helmet was 

usually white, but others 

colors existed, as shown by 

this orange helmet on a pilot 

in front of his bare-metal 

U-2A. This photo gives a 

good view of the periscopic 

sextant just ahead of the 

canopy and the driftsight on 

the bottom of the fuselage 

below the cockpit. 

National Archives College 

Park Collection

respectively). David Clark Company also 

manufactured a special MC-3A (S799) with 

the pressure fittings on the left side.126

All of these suits used pressure gloves that 

had the pressure lead on the thumb side, 

using positive-lock bayonet connections. 

Berger Brother gloves were all leather, but 

David Clark Company used leather palms 

and nylon backs with lacing adjustments.127

The MC-4A (BB-MC-4A and S814) suit 

was the first production suit sized using a 

new 8-size “height-weight” scheme instead 

of the 12 standard sizes defined by David 

Clark during World War II. Instead of 

using a variety of body measurements, only 

the wearer’s height and weight determined 

the size of the suit. Milton Alexander of the 

Biophysics Branch and Fred Moller at Berger 

Brothers developed the new sizing tariff in 

1958 during the development of the CSU2/P.128 Except for the sizing, the MC-4A 

was identical to the MC-4 suit. 

The MC-3/3A and MC-4/4A suits used a 

new Firewel pressure regulator built into a 

seat kit that was used as a seat cushion in the 

airplane. This replaced both the on-aircraft 

regulator and the suit regulator. Under normal 

Below: An MC-4 partial-pressure suit with MA-2 helmet on 

October 3, 1956. Initially, the Air Force ordered the MC-4 

as an MC-3 with an integral G-Suit, but the David Clark 

designers took the opportunity to make other changes that 

improved the usability of the suit. These changes were subsequently made to the MC-3, becoming the MC-3A. 

U.S. Air Force photo. 

Courtesy of the Terry Panapolis Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

159

Below: This was the standard configuration of the MC-4 

with a MA-2 helmet, back parachute, and a seat kit. To provide protection as far down the calf as possible, the Air Force 

issued lowrise boots (or high shoes). Note the adjustment laces 

inside the leg and on the chest. The MC-4 was fabricated by 

Berger Brothers and, as with this particular suit, the David 

Clark Company. 

U.S. Air Force photo. 

Courtesy of the Terry Panapolis Collection

Below: This is Joe Ruseckas at the David Clark Company 

facility showing the back of an MC-4. One of the major 

changes from the MC-3 was the elimination of the horizontal 

shoulder zipper. Note the adjustment lacing on either side of 

the interdigitizing tapes that operated the suit. 

Courtesy of the David Clark Company, Inc.

operations, the regulator pressurized the suit 

and helmet using the aircraft oxygen supply. 

In case of ejection, the source switched to a 

6-minute reserve bottle(s) built into the seat 

kit itself, with the switchover taking 5–9 seconds. Operation was completely automatic, 

providing appropriate breathing and counterpressure up to 70,000 feet. The only controls 

were an on-off switch and a pressure gauge, 

along with the press-to-test button that 

inflated the suit to 6 psi and the helmet to 

60 mm Hg for a few seconds.129

As an experiment, Ed Dubois and Joe 

Ruseckas at David Clark Company 

constructed a suit (S787) similar to the 

MC-4A that used Link-Net for the shoulder 

section. This may have been the prototype 

for the Link-Net shoulder pattern that was 

used in the MC-2 and S901 full-pressure 

suits, but nobody at David Clark Company 

remembers who developed the pattern. 

A second prototype (S802) expanded the 

use of Link-Net from the shoulder to the 

forearm, integrated the G-suit between the 

altitude bladder and the outer covering, and 

incorporated a basket-weave ventilation vest. 

The USAF designated this suit CSU-1/P 

but did not order it into production since 

Berger Brothers was already developing 

the CSU-2/P.130

After the late 1950s, SAC crews were no 

longer routinely required to wear partial- 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

160

Above: David Clark Company S612 partial-pressure suit 

gloves were typical of the gloves used with later pressure 

suits. The gloves had leather palms and nylon backs. These 

particular gloves have the pressure lead on the pinky 

side; the MC-3 and MC-4 suit had pressure leads on 

the thumb side. Note the lace adjustments on the back. 

Courtesy of the David Clark Company, Inc.

pressure suits on operational missions since 

low-altitude nuclear penetration was by that 

time the mandated nuclear mission profile. 

Fighter pilots continued to wear the capstantype partial-pressure suits into the mid-1960s. 

The MC-3A and MC-4A suits were the last 

of the mechanical (capstan) partial-pressure 

suits developed by the USAF until the Tactical 

Life Support System (TLSS) program in the 

mid-1980s. The MC-3A and MC-4A suits 

remained in service with the USAF until 

1964 and considerably later with various 

other air forces.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

161

Left and photo on page 160: Ads such as these are familiar to 

many from the 1960s, selling surplus partial-pressure suits and 

helmets. The ad claims the suits cost the Government $180, 

making the $7.95 asking price quite a bargain, as were the 

$380 helmets that sold for $14.95. It was a bit of a stretch to 

say the garments were “made for American astronauts.”

Courtesy of the David Clark Company, Inc.

Interestingly, during the early 1960s many 

of these early partial-pressure suits, specifically the T-1, MC-1, and MC-3, along with 

the K-1 helmet, were sold in military surplus 

stores. The USAF, however, later recalled the 

suits for sale to NATO nations under the 

U.S. Military Assistance Program although a 

considerable number of these suits remain in 

the hands of memorabilia collectors. It was a 

rite of passage for many baby boomer boys to 

drool over the “Captain Company” advertisements that appeared in James Warren and 

Forrest J. Akerman’s Famous Monsters 

of Filmland magazine, which offered new 

and unissued K-1 helmets for $14.95 and 

the partial-pressure suits used with them for 

only $7.95!131

MC-3A SPECIALS—MANHIGH, 

EXCELSIOR, AND STARGAZER 

Despite its limitations, in the mid-1950s, 

the MC-3 represented the best partialpressure suit available in the western world. 

The USAF provided MC-3A suits to 

support a variety of special projects, 

including three unusual efforts that used 

very high-altitude balloons.

In December 1955, the USAF established 

Project Manhigh to investigate the effects of 

simulated space travel on humans. Since rockets were not yet capable of launching anything 

significant into space, the pilot would ride in 

a pressurized gondola above 100,000 feet for 

a 24-hour balloon flight that would be above 

99 percent of the atmosphere and in the functional equivalent of a space environment. The 

USAF selected three pilots—Capt. Joseph W. 

Kittinger, Jr., Lt. Clifton M. McClure, and 

Maj. David G. Simmons—for the Manhigh

flights. The pilots wore slightly modified 

MC-3A (S836) suits in case of sudden pressure loss.132

The aluminum Manhigh gondola was 8 feet 

high and 3 feet in diameter, and it consisted of 

the upper dome, turret, and lower shell. The 

turret included six portholes, including one the 

pilot could open. After rejecting pure oxygen 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

162

as a fire hazard, the pilot breathed a mixture 

of 60 percent oxygen, 20 percent nitrogen, 

and 20 percent helium. The gondola weighed 

1,648 pounds including the pilot and scientific equipment. At maximum altitude, 

the plastic balloon expanded to a diameter 

of 200 feet with a volume in excess of 

3 million cubic feet.133

Kittinger flew the first flight, Manhigh i, on 

June 2, 1957, and reached 96,784 feet. Simons 

reached 101,516 feet on August 19–20, 1957, 

on Manhigh ii. During this flight, Simons 

took a self-portrait at 100,000 feet that 

became the September 2, 1957, Life Magazine

cover photo. The last flight, Manhigh iii, was 

flown by McClure on October 8, 1958, and 

reached 98,097 feet.134

After his flight, Simons wrote a critique of the 

MC-3A suit. Simons pointed out that the suit 

was intended strictly as an emergency garment 

to be used only if the gondola pressurization 

system failed. Simons indicated he normally 

did not wear the helmet faceplate, except 

when doing pressure checks and switching gas 

bottles. His overall assessment was, “Although 

the suit was well designed and served its purpose well, protecting from depressurization, 

it also caused considerable discomfort with 

a marked loss of effectiveness and efficiency 

during the flight.” Simons indicated that “at 

the end of the flight, the inside surface skin 

of my elbows was literally rubbed raw and 

covered with scabs from the 44 hours of continuous irritation.”135 He also pointed out that 

the insulation value of the helmet was considerably greater than that of the suit, making it 

difficult to achieve a comfortable temperature. 

Perspiration around the torso bladders soaked 

his underwear, causing “considerable distress.”136 Simons admitted his use of the suit 

was outside the norm but offered suggestions 

to improve future suits, several of which were 

incorporated into the CSU-2/P and CSU-4/P 

suits that followed.

The second balloon project was even more 

interesting. As turbojet aircraft flew higher 

and faster in the 1950s, the USAF became 

increasingly concerned with the hazards 

faced by flight crews ejecting from highperformance aircraft. Col. John Paul Stapp 

(1910–1999) led the way with his pioneering 

deceleration research that defined the limits 

of human tolerance. On December 10, 

1954, he earned the title, “The Fastest Man 

Alive” when he rode the Sonic Wind I rocket 

sled to a maximum speed of 639 mph in 

5 seconds and then decelerated in 1.25 seconds with a peak stopping force of more 

than 40-G. For a brief period, Stapp weighed 

6,800 pounds and the windblast and deceleration forces were roughly equivalent to 

ejecting in an open seat at Mach 3 and 

60,000 feet. Stapp personally made 27 of 

the 73 manned sled tests conducted as part 

of the deceleration project.

Born in Bahia, Brazil, Stapp received a B.A. 

in 1931 from Baylor University, Waco, TX, 

an M.A. from Baylor in 1932, a Ph.D. in biophysics from the University of Texas at Austin 

in 1940, and an M.D. from the University of 

Minnesota, Twin Cities, in 1944. He interned 

for 1 year at St. Mary’s Hospital in Duluth, 

MN. Stapp also received an honorary Doctor of Science from Baylor University. Stapp 

entered the Army Air Corps on October 5, 

1944. On August 10, 1946, he was transferred 

to the Aero Medical Laboratory at Wright 

Field as project officer and medical consultant 

in the Biophysics Branch. His first assignment 

as a project officer included a series of flights 

testing various oxygen systems in unpressurized aircraft at 40,000 feet.137

Stapp was also interested in determining the 

capabilities of full- and partial-pressure suits 

to protect pilots during and after ejections. In 

1958, the USAF established Project Excelsior 

(meaning “ever upward,” a name given by 

Stapp) with Joe Kittinger as test director to 

study and investigate these high altitude escape 

problems. Sometime earlier, Francis Beaupre, 

a technician at Wright Field, devised a 

parachute system that would allow pilots to 

safely eject at high altitudes without worrying 

about entering a flat spin as they descended. 

The Beaupre Multi-Stage Parachute system 

used a stabilizer chute that controlled spinning 

and tumbling at high altitudes. An automatic 

system deployed both the stabilizer and main 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

163

In 1958, the Air Force established Project ExcElsior to 

investigate the issues involved in high-altitude escape, 

particularly the performance of pressure suits. Lacking the 

funds for anything more elaborate, the Air Force elected 

to use to use an open gondola suspended under a large 

helium balloon. Joe Kittinger made the third ExcElsior 

jump on August 16, 1960 from 102,800 feet and opened 

his parachute at 18,000 feet.

U.S. Air Force

parachutes at the appropriate speed and 

altitude. Excelsior would determine if the 

system worked as designed.138

Since Excelsior did not have the resources 

to use high-performance aircraft to test the 

new escape system, Wright Field built an 

open gondola to suspend under a 173-footdiameter balloon that held nearly 3 million 

cubic feet of helium. Kittinger made three 

high altitude jumps from the gondola using 

the Beaupre-designed parachute system. He 

made the first jump from 76,400 feet on 

November 16, 1959, but the stabilizer chute 

deployed too soon, catching him around the 

neck and causing him to spin at 120 rpm, 

resulting in over 22-G acceleration at his 

extremities. Kittinger lost consciousness, 

but fortunately, the main chute opened 

automatically at 10,000 feet, and he landed 

without serious injury. The second jump, on 

December 11, 1959, from 74,700 feet was 

much less eventful.139
164

A ground crew assists Joe Kittinger in removing his flight gear 

after the successful flight of Excelsior III. The entire jump 

took somewhat under 13 minutes, with most of that time 

spent under the canopy after the main parachute opened. The 

modified MC-3A partial-pressure suit performed as expected 

except for a failed glove. Despite the appearances, Kittinger 

was fine.

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

165

On the third and final jump on August 16, 

1960, Kittinger jumped from 102,800 feet, 

almost 20 miles above Earth. The ascent took 

1 hour and 31 minutes and broke the previous 

manned-balloon altitude record set by David 

Simmons as part of Project Manhigh. During the ascent, the pressure seal in Kittinger’s 

right MC-3A glove failed, and he began to 

experience severe pain in his hand but did not 

inform his ground crew for fear they would 

order him to abort the test. After falling for 

13 seconds, his 6-foot drogue chute opened 

and stabilized his fall. With only the small 

stabilizing chute deployed, Kittinger fell for 

4 minutes and 36 seconds, experiencing temperatures as low as −94 oF and a maximum 

speed of 614 mph (although, contrary to 

many published reports, Kittinger indicates 

he did not break the speed of sound).140

Years later, as he helped Felix Baumgartner 

at Red Bull Stratos prepare for his attempt to 

break the free-fall parachute-altitude record, 

Kittinger remembered what it felt like: 

When I reached 102,800 feet, maximum 

altitude, I wasn’t quite over the target. So, 

I drifted for 11 minutes with winds that 

were out of the east. I went through my 

46-step checklist, disconnected from the 

balloon’s power supply, and lost all communication with the ground. From that 

moment, I was relying totally on the kit 

on my back. When everything was done, I 

stood up, took one final look out, and said 

a silent prayer: ‘Lord, take care of me now.’ 

Then I just jumped over the side. I had 

gone through simulations many times—

more than 100. But this time I rolled 

over and looked up, and there was the 

balloon just roaring into space. I realized, 

however, that the balloon wasn’t roaring 

into space; I was going down at a fantastic rate! At about 90,000 feet, I reached 

approximately 614 miles per hour. The 

altimeter on my wrist was unwinding very 

rapidly, but there was no sense of speed. 

We determine speed visually when we see 

something go flashing by—but nothing 

flashes by at 20 miles up in the air; there 

are no Signposts when you’re way above 

the clouds. When the chute opened, the 

rest of the jump was anticlimactic, because 

everything had worked perfectly. I landed 

12 or 13 minutes later, and there was my 

crew waiting. We were elated.141

The 28-foot main parachute did not open 

until Kittinger reached the much thicker 

atmosphere at 17,500 feet. Kittinger safely 

landed in the New Mexico desert 13 minutes 

and 45 seconds after he left the gondola.142

This jump set records for highest balloon 

ascent, highest parachute jump, longest 

drogue fall, and fastest speed by a human 

through the atmosphere. These are still current USAF records but were never submitted 

to the FAI to qualify as world records.143

The third balloon project returned to 

scientific research. Back at Holloman AFB, 

Kittinger also took part in Project Stargazer

on December 13–14, 1962. Kittinger and 

William C. White, an astronomer, spent more 

than 18 hours above 80,000 feet performing 

observations. The pilots wore slightly modified MC-3A partial-pressure suits. In addition 

to obtaining telescopic observations from 

above 95 percent of Earth’s atmosphere, the 

flight provided valuable data for the development of pressure suits and associated life 

support systems during a 13-hour stay at the 

edge of space.144

CSU-2/P—ATTEMPT TO IMPROVE 

THE MC-4 

As good as they were, everybody agreed the 

MC-3/4 suits were not perfect, and the Aero 

Medical Laboratory gave Berger Brothers the 

lead in developing a better suit. One objective 

was to create a relatively loose-fitting garment 

that provided better comfort when unpressurized and made donning and doffing easier. 

Creating a loose-fitting garment that offered 

sufficient protection was a difficult assignment 

and required rethinking how the capstan principle worked.145

The Aero Medical Laboratory suggested 

investigating two double-capstan 

arrangements dubbed “double power” 

and “double take-up.” In both cases, two 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

166

Project stargazEr was a balloon astronomy experiment in 

which Joe Kittinger (left) and astronomer William White 

hovered for more than 18 hours above 80,000 feet to check 

variations in brightness of star images. The men are wearing 

modified MC-3A partial-pressure suits. Note the breathing 

oxygen packs on their chests. Each man wore a parachute in 

case they needed to bail out.

U.S. Air Force

capstans were used on each limb, and the 

interdigitizing tapes run in such a way that 

one capstan pulled the fabric from under the 

other capstan (instead of letting it bunch up, 

as in a single capstan system). Berger Brothers 

built models of both capstan arrangements 

and ran extensive laboratory tests to determine 

which was best. Ultimately, Fred Moller 

decided to use the double-power capstan 

arrangement over the torso bladder area and 

the double takeup system over the shoulders, 

arms, and legs.

The increased area (compared to the MC-1 

suit) of the torso and breather bladders in the 

MC-3/4 suits resulted in considerable discomfort because perspiration could not easily 

evaporate. In response, a vinyl-film ventilation 

layer was added under the torso bladder, next 

to the underwear, to provide a constant source 

of ventilating air at appropriate spacing. The 

ventilation layer covered the back from the 

upper shoulders to the buttock and the front 

from the upper shoulder to the groin. The 

layer was perforated with 0.044-inch holes 

spaced approximately 0.21 inch apart. In 

addition, some pilots complained about pain 

in their feet, so Berger Brothers developed a 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

167

pair of pneumatic socks with minimal seams, 

constructed of a lightweight, air-impermeable 

material that could be worn with the regulation flight boots.

Fred Moller constructed the first prototype 

(Model 3904-X1) of what the USAF 

designated CSU-2/P in late 1957. The suit 

included a “tear-away” outer cover intended 

to protect the suit during a high-speed 

ejection, although it also prevented the lacings 

and interdigitizing tapes from snagging on 

objects in the cockpit. After a great deal of 

evaluation, the outer layer was made from 

Brauer Knitting Company A48C stretch 

nylon fabric. The low-friction capstan tapes 

used a nylon-satin weave. Prior to adopting 

that material, Berger Brothers tried various 

heavy tapes and lightweight webs using 

different weaving methods. Some of the yarns 

were Teflon coated prior to weaving, while 

others were coated after weaving. 

The second prototype, Model 3904-X2, used 

a zipper extending from the center-front neck 

down to the waist at a right angle so that the 

suit opened completely on the right side. The 

new arrangement “left a lot to be desired”

and Fred Moller investigated many alternate 

zipper configurations to make the suit easier 

to don.146 The final scheme consisted of three 

separate zippers, one inside each leg from 

the crotch to the ankle and one from the 

neck to the left thigh. Ultimately, the second 

prototype was judged to perform adequately 

and offer greatly increased comfort, but the 

tear-away layer and zipper arrangement still 

needed to be improved.

For unexplained reasons, the third prototype 

(Model 3904-X3) abandoned the doublecapstan system and returned to the traditional 

single-capstan arrangement. Moller developed 

two different tear-away layers for this suit. The 

first was a strong, lightweight Dacron taffeta 

that could withstand the anticipated buffeting during ejection. The second included an 

aluminized finish that provided a bit more 

protection, reflected heat, and looked very 

futuristic. Neither outer layer was judged 

particularly superior during tests.

While he was developing the CSU-2/P suit, 

Fred Moller worked with Milton Alexander 

of the Biophysics Branch to develop a new 

“stature-weight” sizing tariff to replace the 12 

standard sizes defined by David Clark during 

World War II. Instead of using a variety of 

body measurements, only the wearer’s height 

and weight determined the size of the suit. 

Perhaps not surprisingly, given how much 

research went into the original sizing charts, 

Berger Brothers discovered that most sizes 

“required very little change” to match the new 

sizing criteria.147 Given the CSU-2/P never 

entered production, the first use of the new 

tariff came on the later MC-4A suits and the 

improved CSU-4/P suits.

Ultimately, the Aero Medical Laboratory 

decided not to proceed with the CSU-2/P suit 

and concentrated its efforts on the CSU-4/P 

that eliminated capstans. This left the MC-3/4 

as the last of the mechanical counter-pressure 

pressure suits used by the USAF until the 

late 1970s.

C-1A AND C-4—NAVY CAPSTAN 

SUITS

Ejection seats in USAF aircraft generally used 

a ring located between the pilot’s legs, or a 

D-handle on either side of the seat base, to 

initiate ejection. In contrast, early Navy seats 

used a curtain that the pilot pulled down 

over his face and chest to initiate the ejection 

sequence. Therefore, it was necessary for a 

Navy partial-pressure suit to provide sufficient 

mobility to accomplish this task, both pressurized and unpressurized. To this end, the David 

Clark Company developed an experimental 

C-1 suit (S518) specifically to fit Douglas test 

pilot William B. Bridgeman. The C-1 was a 

modified USAF T-1 suit.148

Based on the success of this exercise, 

David Clark Company developed the 

C-1A suit (S520) with a redesigned shoulder 

area that provided sufficient arm mobility 

to reach the ejection seat face curtain. This 

included lengthening the vertical trunk 

circumference so that the wearer could raise 

the clavicle. The arm capstan sizes were 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

168

David Clark’s Joe Ruseckas 

demonstrates that it was 

possible to reach the face 

curtain handles in a North 

American FJ-3 Fury while 

wearing and unpressurized 

T-1 partial-pressure suit. 

This demonstration convinced the Navy to adopt 

modified T-1 suits pending 

the delivery of the dedicated 

Navy C-1 suit.

U.S. Navy photo. 

Courtesy of the David Clark 

Company, Inc.

reduced to the same “limb to capstan ratio” 

as the leg capstans since Naval Aviators complained the T-1 capstans were too large over 

the arms. The crotch area was redesigned to 

better accommodate the Navy parachute harness and improve leg mobility, and the relief 

zipper was extended further into the crotch. 

The normal position of the knees was bent 

backward to provide sufficient mobility to 

place the feet in the ejection seat stirrups. A 

waist-zipper placket was installed to permit 

the wearer to stand more erect and walk 

more easily. Finally, the G-suit connect hose 

was extended to the standard Navy length.149

David Clark Company also created a version 

of the C-1A suit (S676) without the integrated G-suit, although the Navy continued to 

call it a C-1A.150

David Clark Company manufactured prototypes in mid-1955, and once these proved 

satisfactory, the company slightly reworked 

the 12 standard sizes to conform to Navy 

expectations by measuring a representative 

sample of Naval Aviators.151 During early 

1958, David Clark Company created a couple 

of C-1AM suits (S685 and S830) that incorporated the MC-1-style breathing bladder.152

Before the MC-4 was developed, the Navy 

ordered versions of the USAF MC-3 modified 

to allow the pilot to reach the face-curtain 

ejection handle and to provide the same Gprotection as the C-1A suit. These were designated C-4 (S759). After the MC-4 entered 

production, the Navy ordered modified versions as the C-4A (S785). All of these suits used 

ILC Dover MA-2 helmets and Firewel seat kits 

and oxygen panels. Berger Brothers, and possibly others, fabricated equivalent suits.153

CSU-4/P AND CSU-5/P—BLADDERS 

ONLY

Although the MC-3A and MC-4A suits 

offered satisfactory protection in an 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

169

emergency, they were still uncomfortable and 

offered limited mobility, even when unpressurized. An attempt by Berger Brothers to 

develop a more comfortable capstan suit, the 

CSU-2/P, had not been successful and the suit 

never reached production.

Since most long-duration high-altitude 

missions had fallen out of favor for tactical 

reasons, researchers at the Aero Medical 

Laboratory decided any new partialpressure suit would return to the get-medown philosophy instead of the “mission 

completion” concept used for the MC-3/4. 

Development began in October 1956, when 

the Air Force defined requirements for a new 

garment that included providing 5 minutes of 

protection at 70,000 feet plus an additional 4 

minutes to descend to 40,000 feet. The suit 

needed to be quick-donning without assistance 

and be an outer garment worn over a normal 

flight suit. It had to provide a significant 

increase in comfort and mobility over the 

MC-3/4. In addition, the new suit needed to 

include G-protection or be compatible with 

a G-suit, provide adequate ventilation, be 

compatible with existing aircraft oxygen and 

pressurization systems, and fit 90–95 percent 

of the aircrew population.154

Researchers agreed that the desired comfort 

could only be provided by a “loose baggy fit.” 

For this reason, the use of capstans as pressurizing elements was eliminated and the new suit 

would use only inflatable bladders. This was 

a major departure from all previous partialpressure suits. The resulting CSU-4/P emergency partial-pressure suit was developed as a 

cooperative effort of the Aero Medical Laboratory and David Clark Company. Charles C. 

Lutz at the Aero Medical Laboratory was the 

project officer, and Kent W. Gillespie was the 

task engineer. Joseph A. Ruseckas was the lead 

at David Clark Company.

The first prototype was fabricated by 

David Clark Company under contract 

AF33(616)-3329. The suit had separate bladders covering the upper and lower arms and 

lower legs. Each bladder was equipped with 

separable inflation tubes to permit various 

sections to be disconnected. Initial testing 

indicated the suit was a great improvement 

in comfort but also showed excessive ballooning when pressurized at sea level. More 

disturbingly, eight chamber tests—two each 

at 50,000, 55,000, 60,000, and 65,000 feet—

showed the suit did not provide sufficient 

counter-pressure.

Chance Vought test pilot 

Jack Walton climbs 

into his F7U-3 Cutlass 

(BuNo 129600) wearing 

a David Clark Company 

C-4 partial-pressure suit. 

There is a parachute on his 

back, and an emergency 

oxygen bottle on his left leg.

U.S. Navy photos by Chance 

Vought via Don Pyeatt
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

170

The CSU-4P was a bladder type partial-pressure suit that 

used Helenca stretch fabric at the knees and shoulders to aid in 

mobility. The neck consisted of the suit-side neck ring attached 

to a neck skirt. The neck skirt was tucked under the suit torso 

at the neckline and attached to the suit torso with Velcro. This 

suit includes an HGU-8/P full-pressure helmet. Umbilicals 

for communications, visor-seal pressurization, and breathing 

oxygen were attached to the side of the helmet. Gloves were the 

same type used with the earlier capstan partial-pressure suits.

U.S. Air Force

The next two prototypes used different bladder configurations that included overlapped 

bladders, abutted bladders, and continuous 

bladders. Ruseckas added various adjustable 

straps as mobility break lines. These suits 

were subjected to 17 chamber tests at 

altitudes up to 90,000 feet. Researchers 

considered both suits physiologically adequate, but arm and shoulder mobility was 

still unsatisfactory.

The fourth prototype (S822) added Link-Net 

to the shoulders, sleeves, and knees. This suit 

was also the first to integrate G-protection 

and ventilation features into the garment. The 

anti-G bladders were placed under the altitude 

suit bladders (closer to the skin) and provided 

protection equivalent to the CSU-3/P cutaway G-suit. During the evaluation, researchers determined that the arrangement of the 

anti-G bladders was unsatisfactory because 

of excessive bulk and difficulty in donning. 

Researchers realized that including anti-G 

features in the basic suit was greatly penalizing 

its comfort and donning characteristics They 

reasoned that, since not all users would require 

G-protection, it was easier to allow those that 

did to wear the standard CSU-3/P under the 

suit when needed. Further studies concluded 

the pilot could wear the G-suit under or over 

the pressure suit with adequate protection.

The fifth prototype (S822-1) was essentially 

identical to the fourth, except the G-protection and ventilation features were omitted. 

Provisions were made to wear the standard 

MA-3 ventilation garment under the pressure 

suit if needed. In this suit, the Link-Net material over the arms and shoulders was covered 

by a layer of two-way stretch Helenca nylon to 

prevent snagging. Since the suit was intended 

to be loose fitting, lace adjustments were 

deleted from all areas except the wrists. This 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

171

suit also used the new 8-size tariff instead of 

the traditional 12 sizes.

The full-length zipper on the fifth suit permitted easy donning, but the time required 

to engage the two parts of the slider prior 

to closing it detracted noticeably from the 

improvement. Therefore, the sixth prototype 

used three separate zippers: one inside each leg 

extending from the crotch to the ankle, and 

a front slide fastener starting on the left thigh 

and extending to the collar.155 This was essentially the same system recommended by Fred 

Moller at Berger Brothers a year earlier during 

the development of the CSU-2/P.

The Aero Medical Laboratory used the fifth 

and sixth prototypes in a series of altitude 

chamber tests. All volunteers were members 

of the USAF or “medically acceptable undergraduate students from the University 

of Dayton” that had previous experience 

evaluating pressure suits. Each subject wore 

a pressure suit, an MA-2 or MA-3 helmet, 

and a B-4 parachute, and sat in an ejection seat. The tests included 2-hour stays at 

100,000 feet and explosive decompressions.156

At lower altitudes, all of the subjects felt that 

the suit, when properly fitted, allowed more 

mobility than the earlier capstan suits. During the long stay at 100,000 feet, all eight 

subjects believed they could have continued 

for another hour. Although none experienced 

any hand discomfort, the ones not wearing 

pressure socks complained of tingling and 

numbness of the feet. The increased suit pressure made mobility difficult, but all subjects 

completed their assigned demonstration tasks. 

Researchers determined that the suit did not 

appear to interfere with normal blood circulation or cause a shift in tissue fluids. All subjects had a normal electrocardiogram (except 

for tachycardia), no syncope, and expressed 

few subjective complaints.157

After the altitude chamber evaluations showed 

the suit to be suitable, David Clark Company 

manufactured nine garments: four were issued 

to the Air Defense Command, three to the 

Strategic Air Command, and two to the Air 

Force Flight Test Center at Edwards. In general, the pilots found the suit to be a marked 

improvement over the MC-3/4, but as could 

be expected, each offered suggestions for 

improvement. Most of the pilots could don 

the suit in 5 minutes without assistance. 

This compared to subjects at Wright Field 

that could do it in less than 2 minutes but 

had considerably more experience taking 

experimental suits on and off. Researchers felt 

that practice would reduce the donning time 

but admitted that complete dressing (suit, 

helmet, parachute, etc.) could probably not 

be accomplished fast enough to permit a 

5-minute alert unless the pilot was already 

wearing at least the suit. Only one subject 

of the nine wore a ventilation garment under 

the suit, but the other eight subjects indicated 

it was needed. David Clark Company sized 

the test suits to be worn over the standard 

K-2B flight coverall, but most of the subjects did not do so. Nevertheless, the sizing 

appeared adequate for use with or without 

a flight suit underneath.158

Based on this evaluation, the seventh prototype (S822-1A) again incorporated a ventilation layer and repositioned the Link-Net in 

the shoulder area to ease the effort of holding 

the arm in a forward position to grasp a control stick. Unlike the previous suits, which 

were standard sage green, the seventh prototype was orange. The Air Defense Command 

had requested this change to aid in rescue 

operations. This suit also contained pockets 

on the thighs, calves, and arms, much like 

the standard K-2B flight coverall.

The seventh prototype passed its laboratory 

evaluations and the USAF ordered an initial 

50 suits for service tests under operational 

conditions. Later, David Clark Company 

developed the CWU-4/P immersion suit to 

wear over the CSU-4/P during overwater 

operations.159 Several different helmets were 

worn with the CSU-4/P including the 

MA-2, MA-3, and HGU-8/P. The suit was 

worn in the Convair F-102 Delta Dagger, 

Lockheed F-104 Starfighter, Convair F-106 

Delta Dart, Martin B-57 Canberra, and 

Convair B-58 Hustler. The USAF, German 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

172

The David Clark Company CSU-4P was the first partialpressure suit that relied completely upon bladders, instead of 

capstans, to provide the required pressures. Note the restraints 

running from the crotch to the shoulders to keep the suit from 

elongating under pressure. The pilot tightened these after he 

sat down since it was impossible to stand with the restraints 

in place.

Courtesy of the David Clark Company, Inc.

Air Force, Royal Australian Air Force, and the 

Japanese Self-Defense Air Force used the suit.

While not intentionally designed as an exposure suit, the CSU-4/P—or any pressure 

suit—provides some protection against the 

elements. Nevertheless, to provide an integrated pressure-exposure suit, in 1960, the 

Aero Medical Laboratory initiated the development of the CSU-5/P with David Clark 

Company under contract AF33(600)-36627. 

Kent Gillespie was the task manager for 

the Aero Medical Laboratory and Joe 

Ruseckas was the responsible engineer at 

David Clark Company.160

Ruseckas based the first prototype CSU-5/P 

(S848) on the final version of the CSU-4/P. 

The outer bladder served as an anti-exposure 

coverall that incorporated wrist and ankle seals. 

Gloves and boots were worn as separate gar-

ments. A Goodrich pressure-sealing slide fas-

tener extended from the left lower thigh to the 

collar, while leg fasteners extended from the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

173

ankle to the knee area. An integral ventilation 

garment covered the chest, back, and thighs. 

During testing, this garment was not as watertight as desired, so a second prototype included 

plackets (slits) on the leg and wrist closures, 

an improved ankle seal, and a roll seal at the 

collar section. A BDM slide fastener replaced 

the Goodrich zipper that had created pressure 

points on the wearer in the sitting position.161

Environmental testing of the second prototype 

made researchers step back and reconsider their 

approach. Ruseckas decided to adopt the “wet 

suit” principle that allowed him to eliminate 

the watertight entry zipper as well as the neck, 

wrist, and ankle seals. The third prototype also 

moved the ventilation air inlet next to the suitbladder oxygen inlet to make the suit more 

compatible with a greater variety of aircrew 

personal equipment. Thermal insulation was 

provided by two layers of U.S. Rubber Trilok 

(a non-crushable, three-dimensional fabric that 

allows ventilation), although the innermost 

layer did not cover the underarm, crotch, or 

the back of the knees to keep those areas from 

becoming too thick and limiting mobility.

Testing of the third suit showed that the double layer of Trilok insulation did not warrant 

its increase in bulk, so the fourth suit deleted 

one layer. Other changes included making 

the lower leg pocket zippers larger so the 

wearer could place his hands in those pockets 

when huddled in a fetal position. Eyelets were 

installed in the lower corner of all pockets to 

allow them to drain after immersion.

The last prototype incorporated a U-entry 

slide fastener similar to that on the A/P22S-2 

full-pressure suit instead of the vertical front 

slide fastener previously used. The neck collar was made larger to allow the helmet to be 

attached prior to donning the suit. The ventilation system was similar to that used in the 

A/P22S-2. The USAF ordered this configuration into limited production.162

The development and subsequent standardization of the CSU-4/P and CSU-5/P provided 

garments with adequate physiological protection up to 70,000 feet that were reasonably 

comfortable. The counter-pressure bladder 

concept used in the CSU-4/P became the 

industry standard for many years and the garment had a long operational career, lasting 

well into the late 1970s with some users.

HAPS—NASA DRYDEN HIGHALTITUDE PROTECTIVE SYSTEM

Despite being the first operational users of 

pressure suits, the test pilots at Dryden have 

always wanted something that allowed better 

mobility. This has manifested itself in a series 

of slightly specialized versions of the standard 

David Clark pressure suits (generally variants 

of the A/P22S-2 or S-6) and also in a couple 

of local development efforts that in the late 

1970s finally yielded a garment that satisfied 

the test pilots.

In 1972, Dr. William R. Winter at the NASA 

Dryden Flight Research Center awarded 

Space Age Control, a small company located 

in Palmdale, CA, a contract (NAS4-1961) 

to develop a full-pressure Altitude Protective 

Garment (APG) for use during flight-test. 

This 5-month effort eventually spanned about 

8 months as NASA and Space Age worked 

through the requirements and built a single 

prototype. Jimmy B. Graves was the project 

manager at Space Age and Roger J. Barnicki 

was the responsible engineer at Dryden.163

Given that Dryden is located in the middle 

of the Mojave desert, Graves placed primary 

emphasis on a liquid-cooling garment to 

remove heat from the pilot and on the shoulder joints to ensure sufficient mobility. The 

cooling garment fully enclosed the head, torso, 

arms, hands, legs, and feet. Patterns were 

presented during a program design review on 

December 15, 1972, without major comment, 

and Space Age began fabricating the cooling 

garment and a prototype shoulder joint.164

Roger Barnicki tested the liquid cooling garment during January 1973 and determined 

that additional protection was needed around 

the head, so Space Age increased the hood 

tubing from 25 to 39 feet. Preliminary tests of 

the two-axis shoulder joint showed it offered 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

174

good mobility at low torque. A unique load 

transfer ring allowed the use of two singleaxis joints offset by 30 degrees, permitting 

adduction-abduction and transverse motion. 

By the end of January, all of the patterns were 

complete and Space Age began fabricating the 

pressure garment.165

The final design consisted of a spandexand tygon-tubing liquid-thermal garment, 

neoprene-coated nylon pressure bladder, and 

nylon-restraint garment. Entry was via a rear 

vertical slide fastener and lace adjustments 

on the arms and legs allowed sizing. The suit 

used the two-axis shoulder joint and single 

axis joints in the elbows, thighs, and knees. 

Designers formed the single-axis joints by 

pleating (convoluting) the material and stitching a restraint tape over the pleats. The neck 

and wrist rings, relief valves, dual-suit controller, and most fittings were standard A/P22S-2 

hardware supplied by NASA. The suit, helmet, and gloves weighed 23.25 pounds.166

Space Age completed the garment in midMarch and began testing it to criteria previously agreed upon with NASA. In a leak 

check, the suit was pressurized to 3.75 psi for 

15 minutes. Excessive leakage was noted but 

eventually traced to Government-supplied 

hardware (mostly the suit controller). After 

fixing these problems, the suit was then 

pressurized to 5 psi for 1 minute with no 

failures. A test subject donned the suit and 

reported that ventilation was adequate. Space 

Age measured the range of motion measurements with the suit pressurized at 3.75 psi. 

Although mobility was adequate, the pilots 

wanted better.167

Space Age responded by designing a new 

shoulder joint using a thrust bearing. A 

unique feature of this joint was that the bearing was stressed under compression only, eliminating a significant amount of wear and tear 

usually associated with this type of bearing. 

Unfortunately, the new shoulder joint did not 

work as planned. Although the forces required 

to move the joint were lower than a soft fabric 

joint, they were excessive for a bearing joint. 

Engineers traced the problem to excessive flex 

in the outer bearing race and an uneven load 

around the scye opening where the shoulder 

attached to the torso. Because of the flex in 

the outer race, suit leakage was excessive at 

more than 1 liter per minute.168

It appears this was the end of the Space Age 

APG effort and NASA Dryden returned to 

using standard Air Force pressure suits for a 

couple of years. The next effort began almost 

as soon as the APG effort ended. 

In 1976, a group that included Roger Barnicki 

at Dryden, Jewel M. Melvin at the Edwards 

AFB Physiological Support Division, and 

Thomas R. Morgan at the USAF School of 

Aerospace Medicine were joined by Dryden 

test pilot William H. “Bill” Dana and Air 

Vice-Marshall John “J.E.” Ernsting from the 

RAF Institute of Aviation Medicine. Their 

intent was to design a new partial-pressure 

suit for use during flight tests.169

Ernsting spent his entire Royal Air Force 

(RAF) career at the Institute of Aviation 

Medicine at Farnborough, specializing in the 

physiological aspects of flying at high altitudes. 

He was part of the team that developed the 

original RAF jerkin garments. By a happy 

coincidence, during the late 1970s, Ernsting 

was on sabbatical at the USAF School of 

Aerospace Medicine and contributed to the 

Dryden development effort.

The RAF (along with the Canadians and 

Swedes) have never adopted the concept of a 

partial-pressure suit, preferring instead to rely 

on pressure-breathing and later versions of the 

pressure vest and trousers first developed by 

Dr. Henry C. Bazett during World War II. 

By 1956, then-Flight Lieutenant John 

Ernsting was part of a team that developed 

a more sophisticated version of the Bazett 

pressure-breathing ensemble in anticipation 

of what became the British Aircraft Corporation TSR.2 strike aircraft. The RAF believed 

that a pilot breathing 100 percent oxygen 

at 40,000 feet equivalent altitude was thoroughly “capable of the mental and physical 

effort required to fly an aircraft.” Therefore, 

the desired system would provide protection 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

175

for 1 minute at 70,000 feet and an additional 

3 minutes for a descent to 40,000 feet. The 

system would allow nearly unlimited performance at 40,000 feet. The system consisted 

of a pressure-breathing mask, a set of antiG trousers, and a jerkin pressure vest. The 

RAF demonstrated this system could provide 

adequate protection against the effects of pressure breathing at 78 mm Hg for 7.5 minutes 

or 107 mm Hg for 5 minutes. As part of the 

development effort, Ernsting participated 

in altitude chamber runs up to 100,000 feet 

using 133 mm Hg pressure breathing.170

The term “jerkin” is common within the clothing industry, and it means a short, close-fitting 

jacket; it was also used to describe a similar 

sleeveless garment worn by the British Army in 

the early 20th century. The RAF adopted the 

term for its revised counter-pressure vest.

Much like the American partial-pressure suit, 

the British jerkin required a considerable 

amount of development and evolved over 

the years. The garment started with the pressure-breathing vest developed by Bazett, with 

the first major redesign coming during the 1956 

effort with Ernsting. The goal of this latter effort 

was to develop a jerkin that covered as much 

of the torso as possible. One of the first issues 

was testicular pain while breathing at high 

pressures and extending the counter-pressure 

vest through the crotch did not solve the issue. 

Researchers finally determined the problem 

was that the jerkin was rising, much like the 

American pressure suits, and crushing the genitals. The solution was to create an unpressurized 

saddle-shaped area around the genitals.

In the early jerkins, the bladders extended 

only to the top of the groin leaving the inguinal rings completely uncovered when the 

garment was inflated. Physiologists believed 

there was a risk of producing an inguinal 

hernia in some subjects. The RAF G-suit 

provided little support in this region, 

although the American and Canadian suits 

provided more. Eventually, the bladders were 

extended around the circumference of the 

upper thigh to adequately cover the area. 

Conversely, the original jerkins extended far 

up the neck, causing a choking sensation. 

The solution was to lower the neckline, 

although this was limited by a desire to 

maintain protection to the apices of the 

lungs that are behind each clavicle in the 

posterior triangles of the neck.171

Originally, the jerkin and G-suit were worn 

over the flight clothing. Pilots quickly began 

complaining that their movements were 

overly restricted when the ensemble inflated. 

Researchers determined that the jerkin was 

behaving a bit like the capstans on American 

partial-pressure suits, pulling the fabric underneath tight as it inflated. The solution was to 

wear the jerkin under the flight suit (but over 

elastic long underwear).

Back at Dryden, a new generation of fighter 

aircraft was again making test pilots desire 

more comfortable get-me-down garments. 

Newly arrived F-15s were capable of 

routine operations between 50,000 feet 

and 60,000 feet, but the aircraft were not 

equipped to use full-pressure suits. The 

Dryden test pilots considered the existing 

Air Force partial pressure suits too confining 

for the detailed research flights that NASA 

needed to fly. The aircraft could be modified 

to use full-pressure suits—all of the engineering existed for the aircraft delivered to the 

Israeli Defense Forces and Streak Eagle. 

However, the test pilots had reservations 

because the helmet and neck ring reduced 

the field of vision and the gloves restricted 

hand and finger dexterity. The pilots felt 

this resulted in pilot fatigue and reduced 

mission effectiveness.172

As an alternative, Dryden decided to evaluate 

the get-me-down garment used by the RAF. 

Although the concept dated to World War II, 

the then current version had been in service 

for over 15 years. Roger Barnicki and Bill 

Dana traveled to the RAF Institute of Aviation 

Medicine at Farnborough for indoctrination 

training. The ensemble consisted of a jerkin, 

a P/Q pressure-breathing mask, and a dual 

bladder G-suit provided by the David Clark 

Company. A sample ensemble was brought 

back to the United States and jointly tested by 

Dryden and the USAF School of Aerospace 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

176

Medicine. Prior to flight tests at Dryden, Tom 

Morgan at the School of Aviation Medicine 

conducted altitude chamber testing to validate 

the ensemble. The test subjects confirmed the 

need for pressure-breathing training, but the 

result was enhanced performance at altitude. 

The results of this laboratory evaluation gave 

the pilots and life-support personnel confidence in the equipment.173

The jerkin provided by the RAF was a torso 

garment consisting of a single oxygen bladder 

that applied a pressure to the entire torso. The 

jerkin bladder was pressurized by the breathing 

oxygen regulator through a valve in the hose 

to the P/Q pressure-breathing oronasal mask. 

The regulator output was proportional to the 

aircraft cabin altitude with a maximum output 

of 72 mm Hg. A check valve in the jerkin’s 

oxygen bladder prevented oxygen flow from 

the bladder to the mask. The G-suit consisted 

of trousers with two bladders and two inlet 

hoses. One inlet hose connected to the oxygen regulator and the other to the barometric 

G-valve. The barometric G-valve responded 

to a positive G-load or a fall in cabin pressure. 

The suit operated within the 70-psi pressure 

available in the F-104s and F-15s operated by 

Dryden, therefore no modifications to either 

aircraft type were necessary.174

The P/Q mask used a reflected edge seal that 

could deliver up to 100 mm Hg (1.93 psi) to 

the respiratory tract without serious leakage. 

The mask covered the nose and mouth and 

rested on the anterior portion of the chin 

rather than under the chin. Two tension settings were available, and the pilot manually 

operated the tension to the high setting when 

cabin depressurization occurred. The tension 

was returned to the low setting when mask 

leakage was not a problem. The pilots preferred this mask to standard USAF units since 

it did not rotate down and under the chin 

during acceleration.175

NASA test pilots Bill Dana and Einar K. 

Enevoldson performed flight tests using a 

two-seat TF-104G. The pilot in the front 

seat wore an A/P22S-6 full-pressure suit, and 

the pilot in the rear seat wore the jerkin. Four 

cabin decompressions were performed, two 

at 50,000 feet, and two at 60,000 feet. The 

pilot in the jerkin had control of the aircraft 

and did not know when the decompression 

would occur. In each case, the pilot in 

the jerkin flew the descent to 20,000 feet, 

demonstrating the overall performance and 

safety of the jerkin ensemble.176

Based on these results, testing was extended 

to the fully instrumented F-15A test 

aircraft. Bill Dana flew the F-15 in level 

flight at 55,000 feet and Mach 1.4 prior 

to cabin depressurization. As a result of 

depressurization, the cabin pressure went 

from 346 mm Hg (6.7 psi, or 20,150 feet) 

to 77 mm Hg (1.49 psi, or 53,480 feet) 

in approximately 11 seconds. Surprisingly, 

the F-15 has a lower cabin altitude (higher 

cabin pressure) than aircraft ambient altitude 

because of the aerodynamics of the F-15, 

which has a greater ram-air effect than the 

F-104. At high angles of attack, the-F-15 

exhibited even greater reductions in cabin 

altitude during depressurizations. Therefore, 

during an emergency, such as the loss of the 

canopy seal, the pilot in the F-15 could expect 

a higher cabin pressure (lower cabin altitude) 

than his indicated altitude. Safety aspects 

therefore favor the F-15 as a test aircraft due 

to lower than indicated altitude exposure.177

After the F-104 and F-15 tests, the pilots 

reported that their hand dexterity and field of 

vision were the same as when wearing a flying 

suit. The pilots also reported that the British 

ensemble provided unimpeded mobility in 

the cockpit and was very easy to don and 

doff. The only drawback reported was the 

heat buildup due to wearing both the jerkin 

and the anti-G trousers while in the aircraft 

taxing to the runway. Both Bill Dana and 

Einar Enevoldson considered this preferable 

to the disadvantages of wearing a full-pressure 

suit.178 It should be noted that both pilots 

had extensive experience wearing various fullpressure suits during flights tests.

Given the unqualified endorsement of Dana 

and Enevoldson, and the concurrence of 

Roger Barnicki and Jewel Melvin, Dryden 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 4: Partial-Pressure Suits

177

NASA test pilot William H. Dana shows the jerkin-based 

flying outfit used by pilots at the Dryden Flight Research 

Center. This ensemble consisted of a pressure-breathing vest, 

a P/Q pressure-breathing oronasal mask, and a cutaway 

dual-bladder G-suit provided by the David Clark Company 

and it provided adequate protection up to 60,000 feet. 

The Dryden test pilots found this ensemble provided better 

mobility and was cooler than any of the available partial- or 

full-pressure suits.

NASA

adopted the jerkin ensemble as an operational 

suit for flights up to 60,000 feet. By 1980, 

however, the RAF supplied jerkins began to 

reach the end of their service life so David 

Clark Company made replacement garments 

that were generally similar to the originals. 

These garments reached the end of their service lives in the late 1980s, and David Clark 

Company again fabricated replacements. 

No further garments have been made, so it 

appears Dryden no longer has an operational 

high-altitude suit.179

The experience gained with the jerkin ensemble at Dryden formed the inspiration for the 

Contingency Altitude Protection Suit that 

became the Space Shuttle Launch Entry Suit 

after the Challenger accident.
5
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

179

5: Navy Full-Pressure Suits

Since 1942, researchers at the Naval Air 

Crew Equipment Laboratory (NACEL) 

in Philadelphia, PA, had conducted basic 

research in biological, psychological, and 

human engineering aspects of aviation 

medicine related to personal and safety 

equipment. Special facilities at the NACEL 

included, among others, an altitude chamber, 

underwater test facilities, a complete liquidoxygen laboratory, and an escape-system 

recovery net capable of catching ejected freeflight seats and capsules. During World War 

II, the Navy monitored the progress of the 

Army MX-117 full-pressure suit program and 

evaluated several of the suits at the NACEL. 

At the time, there was little need for a fullpressure suit since Navy aircraft typically did 

not fly at high altitudes. However, after the 

war, the Navy became increasing progressive as 

the service struggled to maintain its relevance 

in an era of supersonic aircraft and atomic 

weapons. In addition, the Navy was looking 

toward outer space, perhaps even more so 

than the Army. In early 1947, naval officials 

proposed the Army continue developing the 

Henry partial-pressure suit, while the Navy 

took over the effort on full-pressure suits. The 

Army, still unhappy from its wartime MX-117 

experience, and having lost its lead researcher, 

John Kearby, to an airplane accident, was 

agreeable. At least for the short term.

During 1946, the Navy awarded contract 

NOa(s)-8192 to the Strato Equipment 

Company of Minneapolis. This was the 

company founded by John D. Akerman in 

early 1942, although by 1947 Akerman was 

listed only as a “consultant.” The company had 

previously developed the Boeing, Akerman, 

Bell, and Mayo (BABM) series of pressure 

suits for Bell and Boeing as part of the Army 

program during 1943. The Navy effort appears 

to have been separate from the earlier Army 

effort, although it is unclear if the Model 7 suit 

that Strato ultimately delivered to the Navy was 

the seventh developed under that contract or 

was the BABM-7 suit from the previous effort.1

Akerman designed the Strato Model 7 to 

provide altitude protection up to 60,000 feet 

and limited acceleration protection. The onepiece, tight-fitting garment covered the entire 

body except the face, which was covered by 

a detachable “goggle-mask.” The suit, minus 

the Government-supplied regulator, weighed 

The Strato Equipment Company developed this Model 7 fullpressure suit for the U.S. Navy during 1947. Unlike most of 

the suits created for the Army Air Forces during World War 

II, most of the postwar suits developed for the Navy were 

fairly tight fitting.

U.S. Navy photo 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

180

Top: The single diagonal zipper was a preview of what Russell 

Colley would eventually use on the Goodrich Mark IV suit. 

The Model 7 used a layer of nylon cloth on either side of the 

neoprene-rubber gas container, but all of the layers were integrated into a single zipper to make donning and doffing easier.

U.S. Navy photo 

Courtesy of the David Clark Company, Inc.

Middle and right: Many of the early Navy suits dispensed 

with a hard-shell helmet in favor of a pressurized cloth head 

covering. In the case of the Strato Model 7, the “goggle-mask” 

had an integral pressure-breathing mask and standard-issue 

Navy goggles. Note the large oxygen regulator on the chest.

U.S. Navy photos. Courtesy of the David Clark Company, Inc.

13.25 pounds. The single suit that Strato 

delivered was sized to fit “a very large man,” 

but Akerman believed that only four sizes 

would cover all pilots since the chest, stomach, helmet, and arm length were adjustable. 

Two layers of nylon cloth provided protection 

for the neoprene sandwiched between them 

against local abrasions. According to Strato, 

“the smooth slippery surface makes it resistant 

to scratches and tears from sharp protrusions 

in the cockpit.”2

Five-finger gloves (as opposed to mittens) had 

zippers along the top to permit donning and 

doffing. The Model 7 glove used a custom 

zipper that was “tedious to close,” but it could 

have used the standard Goodyear flap zipper or 

a new airtight zipper developed by the Durkee 

Atwood Company of Minneapolis.3 There 

was a neoprene diaphragm at the intersection 

of the glove and sleeve that allowed the suit 

to remain pressurized when the glove was 

removed. The gloves had separate ventilation 

and pressurization channels to provide comfort 

even when the suit was not pressurized.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

181

The narrow-neck, close-fitting helmet covered 

the entire head and ears and was fabricated of 

the same material as the suit. Ventilation and 

pressurization of the helmet was through three 

flat, noncollapsible conduits that discharged 

air just above the ears and into the goggles. 

“Donuts” made of soft sponge rubber and 

chamois cloth protected the ears. The gogglemask consisted of standard Navy goggles and 

a pressure-breathing mask integrated into a 

single unit.

Apparently, the initial Model 7 suit functioned primarily as a full-pressure suit. Akerman fabricated a second Model 7 that could 

function as a heating and cooling garment, 

a G-suit, a pressure-breathing ensemble, and 

a pressure suit, or any combination of the 

four as needed. The suit could also be used 

as an exposure garment after bailing out 

of an airplane.4

 The second suit included a 

pressure-breathing vest that covered the entire 

chest and abdomen. It was tested in the Mayo 

Clinic altitude chamber up to 53,000 feet 

with satisfactory physiological results, but 

Akerman did not describe how flexible the suit 

was under pressure. John B. Werlich, a former 

Army pilot, tested the acceleration protection 

of the suit on the Mayo centrifuge under the 

direction of Earl Wood. Werlich also tested 

the David Clark Model 21 G-suit at the same 

time as a comparison. The Strato suit provided 

slightly more protection than the Clark suit 

but was judged much more uncomfortable at 

1-G, not surprising given it was much heavier 

and bulkier since it could also function as a 

pressure suit.5

When Strato delivered the second suit to the 

Navy, it included a list of recommendations 

that primarily centered on the Navy further 

funding development of the suit. There were, 

however, a few other recommendations, such 

as incorporating an integral life preserver 

that would automatically inflate and keep 

the wearer at a 45-degree angle in the water.6

There is no record that the Navy funded further development of the Strato suit, having 

set its sights instead on developments at the 

David Clark Company.

In late 1947, the Navy awarded the David 

Clark Company contract NOa(s)-9931 for 

the development of an Omni-Environment 

Suit for use in emergencies. It appears that, at 

least originally, this was a get-me-down suit 

(and was not meant as a primary life support 

system), although one that could be used for 

extended periods if needed. During the development effort, David Clark Company used 

alphabetical designators (Experiment A, B, 

C, etc.) for in-house experimental suits and 

numeric designators (Model 1, 2, 3, etc.) for 

suits delivered against the contract.

David Clark Company constructed the 

Experiment A suit primarily to determine 

how much pressure the selected material 

would withstand and how much it stretched. 

The designers used the pattern developed for 

the Henry partial-pressure suit since it had 

essentially the desired size and shape. The 

suit was sealed at the neck, wrists, and lower 

calves, and since nobody would wear it, it 

did not use a helmet, gloves, or boots. The 

pressure garment was stitched together using 

plain 0.375-inch joining seams covered by a 

single layer of gummed tape. The amount of 

stretch under pressure was measured at the 

chest, armpit, bottom torso, and crotch. The 

chest measurement, for example, increased 

approximately 1 inch for each psi of pressure 

applied until it failed at the crotch at 3 psi. 

David Clark determined this fabric was 

unacceptable due to the amount of stretch and 

low failure pressure.7

A second suit, Experiment B, was constructed 

on November 22, 1948, using a bladderand-case construction technique similar to 

a G-suit. Neoprene-coated nylon twill bladders held the pressure, and the basket-weave 

nylon outer case controlled stretch. David 

Clark Company manufactured the bladder to 

enclose the entire body, except the neck and 

head, in a sitting position. An unusual plexiglass helmet was attached using a bayonet seal 

at the neck, and a compressed-air fitting was 

installed in the rear left waist area. Zippers on 

the shoulders, arms, and lower calves cinched 

the suit tight against the occupant.8
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

182

LCDR Ralph L. Christy, LT Paul C. Durup, 

and Dr. Kenneth E. Penrod evaluated the 

Experiment B suit at Worcester. Penrod was a 

physiologist at Boston University and a parttime consultant to David Clark Company. 

He would later leave Boston to become a 

dean at Duke University School of Medicine, 

largely ending his day-to-day involvement 

with pressure-suit development.9 The suit was 

The first of the David Clark pressure suit for the U.S. Navy 

was this Experiment A. Obviously, this suit was never 

intended for anybody to wear—it was sewn closed at 

the neck, hands, and feet. The designers used this suit to 

determine a candidate fabric’s reaction to pressure.

Courtesy of the David Clark Company, Inc.

Dr. Kenneth Penrod, a consultant to David Clark Company, 

in the Experiment B suit. The unusual helmet showed up 

in several David Clark suits, as well as those from other 

companies. The suit allowed a fair amount of mobility, as 

demonstrated by Pendrod holding his bended arm to touch the 

side of the helmet. Note the mittens instead of fingered gloves.

Courtesy of the David Clark Company, Inc.

The Experiment B suit in the cockpit of a Vought F4U the 

Navy had loaned David Clark Company during July 1949. 

One of the major failings of the Experiment B suit, and most 

early pressure suits, was a lack of ventilation that caused the 

wearer to perspire excessively.

Courtesy of the David Clark Company, Inc.
As could be expected, the Model 1 was generally similar 

to the Experiment B suit that had preceded it. Here, Joe 

Ruseckas demonstrates the Model 1 during early 1949. The 

small-diameter tubes on the legs and wrists were a temporary 

method of providing some ventilation to the extremities. In 

general, the military was impressed with this suit, finding it a 

marked improvement over the wartime suits.

Courtesy of the David Clark Company, Inc.

somewhat too large for Christy and Durup, 

resulting in unacceptable ballooning under 

pressures up to 2.5 psi. Fortunately, the suit 

was a better fit for Penrod who was able to 

stand, crouch, and move his arms with the 

suit pressurized at 2 psi. The overall conclusion was that the garment might offer a “practical method of constructing a full-pressure 

suit which is light in weight, has adequate 

strength to withstand the required pressures, 

and will not excessively hamper the wearer’s 

movements in either the deflated or inflated 

condition.”10 It was noted that the suit needed 

better ventilation to remove perspiration.

This test provided the confidence for David 

Clark Company to fabricate the Model 1 

that was, in general, similar to Experiment 

B. The suit approximated the position of a 

seated pilot and provided limited adjustment 

via nylon cord lacings to better fit a variety of 

men. Mittens, where the thumb was separate 

but the four fingers were together, covered 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

184

the hands. The pilot donned the suit through 

a 34-inch horizontal zipper along the upper 

back. David Clark noted that the zipper, 

which his company had designed and manufactured, did not always seal correctly and 

would need to be modified in the future. 

Ken Penrod demonstrated the Model 1 on 

January 26, 1949, at the NACEL. The suit 

was pressurized with pure oxygen to between 

2 and 3 psi, but the available source was 

not sized properly and made it impossible 

to maintain a constant pressure. Overall, 

the demonstration was a success, although 

a weakness in the crotch was again evident. 

Penrod took the suit back to Worcester, and 

David Clark Company reinforced the crotch 

and several other seams before returning it 

to Philadelphia on February 2, 1949. While 

the suit was in Worcester, Penrod evaluated 

its mobility in the cockpit of a Vought F4U 

Corsair the Navy had provided to David 

Clark Company. Penrod demonstrated it 

was possible to move the rudder and stick 

controls to their extreme positions and work 

the throttle and toggle switches, although 

everybody admitted the mittens were “quite 

clumsy.”11 In addition, the back zipper 

still leaked but David Clark Company was 

designing a new closure. This suit was also 

evaluated by researchers from the USAF Aero 

Medical Laboratory, although it is unclear if 

they did so in Philadelphia or at Wright Field. 

The Air Force evaluators found the suit to 

be a marked improvement over the wartime 

Goodrich suits but still found it lacking when 

compared to the partial-pressure suits under 

development by the Aero Medical Laboratory 

and David Clark Company.12

The Navy and David Clark Company both 

agreed that it would be prudent to test the 

absolute strength of the suit by pressurizing 

it until it burst. Not wanting to sacrifice the 

Model 1 suit, David Clark Company constructed Experiment C for this purpose. David 

Clark Company sealed the neck with a circular piece of 0.125-inch-thick plexiglass that 

proved to be the weak point in preliminary 

tests, cracking at 6 psi. The designers replaced 

it with a 0.25-inch-thick piece and it was 

then possible to pressurize the dummy suit 

to 10 psi without rupturing it. This was very 

close to the bursting point, however, since an 

additional increase of about 0.25 psi caused 

the inner suit to tear at the left hip. The outer 

suit did not suffer any damage.13

Researchers concluded that the bladder ruptured because it had reached its maximum 

stretch before the outer case. Nevertheless, the 

Navy agreed that 10 psi was well beyond the 

nominal needs and safety factor for any suit, 

and no further stress testing was conducted. 

The tests also revealed a great deal about the 

behavior of the suit in general. For instance, 

at 1 psi the belly measured 41 inches in circumference, gradually increasing to 42 inches 

at 4 psi and 43.75 inches at 10 psi, a 2.75-inch 

increase. The top of the thigh increased from 

24.875 inches circumference at 4 psi to 

25.375 inches at 1 psi and 25.875 inches at 

10 psi. In general, the test revealed that there 

was little increase in size between 1 psi and 

3 psi, which was the nominal working pressure of the suit.

David Clark Company also created a new 

helmet with a different neck seal that made 

it easier to don and doff. The entire helmet 

was made of plexiglass with a saddle-piece 

base contoured to fit the shoulder. Unfortunately, the helmet could not be used with the 

Model 1 suit since the shoulder piece made 

it necessary to lower the rear entry zipper on 

the suit to a point that it was too difficult to 

get the head through the neck opening. The 

company also experimented with detachable 

limbs so that the length of the arms and legs 

could be changed for to individual pilots. A 

quick detaching airtight coupling was made of 

two plexiglass cuffs, one telescoping inside the 

other, with a rubber sealing-dam between the 

two cuffs. A prototype seal was constructed 

and appeared to work under pressure.

The company fabricated Experiment D 

in January 1949, building upon what had 

been learned. For the Model 1 suit, the pilot 

donned the inner and outer layers as a single 

unit; for Experiment D, the layers were two 

garments. This meant that a different method 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

185

One of the problems with all previous suits was that each of 

the researchers and evaluators were different sizes, meaning 

only a few of them could wear each suit comfortably. The 

Experiment D suit used a series of lace adjustments to allow 

some tailoring to fit various individuals. Note the normal 

five-fingered gloves instead of the quasi-mittens used on the 

earlier David Clark suits. A close examination of the helmet 

shows the built-in earphones. Ken Penrod is wearing the suit, 

with John Flagg (left) and Dave Clark (right) looking on.

Courtesy of the David Clark Company, Inc.

of securing the helmet was needed, and David 

Clark Company settled on a separating zipper 

with one half sewn around the neck of the 

outer garment and the other half clamped to 

the base of the helmet seal. A vertical front 

zipper that ran from the neck to the crotch 

replaced the horizontal back entry zipper. The 

zippers functioned satisfactorily under pressure, but they were problematic since the tight 

fit of the outer garment made it difficult to 

close the upper half of the front zipper, and 

everybody had trouble getting the separating 

helmet zipper to start. The designers also tried 

a diagonal chest zipper (like the much-later 

Navy Mark IV) but it appeared to offer no 

advantages over the vertical zipper.

The Experiment D suit attempted to cure 

ballooning around the feet. The leg of the 

outer suit extended downward over the instep, 

and two straps crisscrossed under the arch of 

the foot and were drawn tight using D-ring 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

186

John Flagg wears the Model 2 suit seated next to the F4U 

cockpit (extreme right) in Worcester with Ken Penrod in 

the background. For this suit, David Clark Company 

eliminated the lace adjustments and tailored the suits for 

each individual. Note the zippers coming down from the 

shoulders into the arms, across the upper chest, and vertically 

down to the crotch. Initial attempts at finding an effective 

manner to don and doff a pressure suit were elusive.

Courtesy of the David Clark Company, Inc.

buckles. This effectively prevented the suit 

from forcing itself away from the wearer’s foot, 

and there was little difference in appearance in 

the inflated or normal condition except for a 

slight bulging under pressure. Normal heavyduty, high-cut shoes were worn over the bladder suit. With this arrangement, the use of the 

feet was no longer impeded by oversized footwear not in direct contact with the pilot. At 

the time, it was believed that this satisfactorily 

solved the known problems connected with 

pressurizing the feet.

A series of lace adjustments on the shoulders, arms, and legs allowed the suit to be 

customized within limits. Steps were also 

taken to improve the hands by replacing the 

mittens with five-fingered gloves made of 

nylon basket-weave fabric. The gloves were 

made separate from the rest of the suit and 

restrained from blowing away from the hand 

by a thong sewn to the cuff of the sleeve and 

looped over the thumb. The thong was drawn 

tight by means of small D-rings. Two pieces of 

0.125-inch-diameter wire, fastened across the 

palm of the hand and around the base of the 

thumb, kept the glove from ballooning. This 

arrangement made the hand more versatile, 

and much finer movement of the fingers was 

possible. Samples of handwriting taken under 

various pressures showed little change as the 

pressure increased. Despite this success, gloves 

continue to be an issue, even today.

The designers discovered that, because of 

the small volume of the plexiglass helmet, it 

was not necessary to wear earphones in the 

customary manner or to speak directly into a 

microphone. Therefore, the earphones were 

mounted on the sides of the helmet adjacent 

to the ears, and a small microphone was built 

into the base of the helmet in front, removing 

them from direct contact with the pilot.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

187

Until this time, all pressure suits had been 

inflated via a single fitting, usually located on 

the left side of the waist. Experiment D broke 

with this tradition and used five inflation 

points: the normal waist fitting, plus fittings 

near each glove and each foot. The intent was 

to promote better air circulation to keep the 

wearer more comfortable. When Ken Penrod 

tested the suit with a flow rate of about 

56 liters per minute, he confirmed it was 

generally more comfortable and there was 

less evidence of perspiration than with 

previous suits.

Experiment E was generally similar to D 

except that it returned to a horizontal back 

entry zipper, and the bladder suit was 

permanently attached to the helmet. The 

five-fingered gloves were also permanently 

attached to the bladder suit, eliminating 

the need for the loops over the thumbs to 

keep them in place. The suit was extensively 

tested in Worcester, frequently being worn 

pressurized for 2 hours at a time. After some 

practice, Ken Penrod could don the suit in 

under 30 minutes, although an assistant was 

required to close some of the zippers that 

were out of reach. Penrod used the stationary F4U cockpit to verify the mobility of the 

suit, and he could successfully climb into 

and out of the cockpit wearing the standard 

seat-type parachute and perform all normal 

piloting tasks. However, rigidity across the 

lower waist and groin made it difficult, and at 

times impossible, for Penrod to bend forward 

sufficiently to reach the lower parts of the 

instrument panel. Researchers noted the crash 

harness made it difficult to reach these areas 

even while wearing only a normal flight suit.

These experiments gave way to the Model 2, 

fabricated in April 1949. The David Clark 

Company made two suits: one to fit a man 

6-feet, 2-inches tall and weighing 175 pounds, 

and the other to fit a man 5-feet, 9-inches tall 

and weighing 173 pounds. In general, these 

were similar to the Experiment E suit except 

that all lacing adjustments were eliminated 

and each suit was tailored for its wearer. These 

suits were used for extensive ventilation tests 

that proved generally satisfactory. In fact, on 

July 19, Dr. Arthur S. Iberall of the National 

Bureau of Standards witnessed one of these 

tests and requested a third suit be manufactured to fit him for further tests in his laboratory. David Clark delivered the Iberall suit on 

September 15, 1949.14

Based on tests of the Model 2 in Worcester, 

the NACEL requested that David Clark 

Company freeze the design and manufacture 

a single suit for LCDR Harry V. Weldon. 

This Model 3 included a device to resist the 

tendency for the shoulders and helmet to lift 

when the suit was pressurized. One of the 

major objections the Navy had to the 

Model 2 suit was the cylindrical plexiglass 

helmet, primarily because it was too 

John Flagg shows the 

bladder of the Model 3 in 

March 1950. The designers 

uncoupled the outer restraint 

layer from the gas container 

in an attempt to increase 

mobility. The unusual 

clear-plexiglass helmet of 

the earlier suits gave way to 

a modified partial-pressure 

suit helmet with a face seal.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

188

Top right and left: The Model 3 was a tight-fitting suit and 

did not change substantially in appearance as it pressurized 

(photo at right). Note the capstan on the chest that pulled 

excess material down from the neck so that it did not get in 

the way of turning the head. It should be noted the capstan 

did not contribute to the pressurization function, as with a 

partial-pressure suit, but was simply used to eliminate excess 

fabric bunching up at the neck as the suit elongated. John 

Flagg is wearing the suit.

Courtesy of the David Clark Company, Inc.

large to fit in most fighter cockpits. For the 

Model 3, David Clark Company made a 

helmet using the same fabric as the suit and 

the inner gas-tight layer was permanently 

attached to the inner layer of the suit. The 

outer restraining layer was attached by zippers and telescoped over the neck of the 

lower suit, floating freely. Initial attempts to 

permanently attach the outer layer resulted in 

the head being immobilized since it was necessary to twist the tube formed by the neck. 

By decoupling the outer layer, a satisfactory 

amount of turning was possible when the suit 

was deflated.15

However, under pressure, it was only possible 

to rock the head back and forth and from side 

to side, and even this limited head mobility required a fair amount of extra material 

around the neck. To overcome helmet lift 

resulting from this excess material in the neck, 

David Clark Company incorporated a capstan 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

189

about 9 inches long and 8 inches in circumference when fully inflated. The capstan was 

mounted on a curtain fastened to the bottom 

of the helmet face frame and to a point on the 

chest. When the capstan pressurized, interdigitizing tapes took up several inches of fabric 

to provide the required counter-pressure. The 

plexiglass faceplate had sufficient volume to 

use a normal oxygen mask. David Clark 

delivered the Model 3 suit to the Navy on 

March 8, 1950.

Although not incorporated into the Model 3 

suit, David Clark Company investigated using 

an open-weave net fabric to counter ballooning and helmet lift. These fabrics contracted 

vertically, but not horizontally, as the suit 

inflated. It appeared the fabric might allow 

making the torso and limbs long enough so 

that a man could stand erect and move about 

freely when the suit was depressurized yet 

eliminate ballooning and the resultant discomfort and limited mobility when the suit 

pressurized. David Clark Company made 

an experimental suit from the fabric that 

CDR Frank S. Voris, LCDR Harry V. Weldon, 

and H.R. Geider evaluated at the NACEL 

on March 15, 1950, with generally positive 

results. The company also noted that the 

manner in which the cloth was cut was 

extremely important due to different stretch 

and contracting features in the warp, fill, and 

bias directions. The designers believed that, 

given enough experimentation, the inherent 

features of the material could be used to control the inflated shape of the suit.16

By October 1950, it was obvious to Navy 

Bureau of Aeronautics (BuAer), David 

Clark Company, and the NACEL that the 

open-weave fabric should be used for the 

entire outer garment of a full-pressure suit. 

To this end, experimental suits were made 

to test various aspects of the material. The 

Experiment F suit used a bladder and helmet 

identical to the Model 3 with an outer layer 

of open-weave net fabric. Several different 

fabrics were used on various parts of the suits 

to determine which was best. The lessons 

learned from this suit were incorporated into 

Experiment G. However, the position the 

suit assumed when pressurized was not satisfactory—the legs were too wide spread and 

the arms were not close enough to the torso. 

Further experiments using this suit convinced 

David Clark that the net fabrics would not 

provide a satisfactory answer for controlling 

torso length although the open-weave fabric 

limited ballooning and increased comfort for 

all other areas of the suit.17

For the torso, designers were unable to reconcile standing up comfortably while unpressurized and sitting in the conventional flying 

position at 3 psi without excessive ballooning. 

The extra length of the front and sides of the 

torso, required for standing erect, was too 

Joe Ruseckas in the Experiment H suit. This suit used the 

same gas container and helmet as the Model 3, but it used 

a knit-fabric restraint layer that was supposed to control 

ballooning and increase mobility. It did not work that way, 

but the experiments with knit fabrics continued with some 

successes and may have, indirectly at least, played a role in 

the eventual development of Link-Net. 

Courtesy of the David Clark Company, Inc.
190

John Flagg shows the 

“hole in the top” helmet used 

on the Experiment K suit. 

This innovation largely 

solved the issue of helmet 

rise upon pressurization. 

Unfortunately, this left the 

top of the head unprotected 

and researchers worried 

this might lead to 

unknown, and undesirable, 

physiological problems.

Courtesy of the David Clark 

Company, Inc.

great to be compensate for the contraction of 

the fabric that occurred when sitting. Several 

attempts were made to solve this dilemma. 

The first involved using a vest-like garment 

with a separate zipper at the crotch that was 

fastened after sitting down and this effectively 

kept the torso from elongating (ballooning). A 

more satisfactory answer incorporated a gusset 

that used a horizontal zipper across the lower 

front of the restraining layer. This zipper was 

open while standing erect and had to be closed 

before the suit could be inflated. Experiments 

continued to find a better solution.

A different fabric was used for Experiment 

H, which again used the same bladder and 

helmet design as the Model 3. The outer net 

fabric was finished in such a way as to make it 

stiff—an attempt to minimize the “slipping” 

characteristic (the knots of the fabric moving 

along the threads) of net fabrics and to provide greater strength at the seams. The small 

gains in these areas were offset by the stiffness, 

which hindered mobility.

Experiment J returned to the same open weave 

fabric used on the F and G suits with different 

sewing techniques. The earlier suits had shown 

the material was not strong enough to control 

the torso while pressurized due to the amount 

of slipping in the fabric and inadequate tensile 

strength. After considerable experimentation, 

designers found that cutting two sets of patterns on opposite biases improved the strength 
191

of the fabric considerably. Combined with 

innovative seam stitching, this appeared to 

offer a solution and initial tests indicated the 

concept might work.18 Although not directly 

related to the later development of Link-Net, 

it is possible these experiments with openweave net fabrics planted some seed of an idea 

into David Clark’s mind.

Having largely solved the restraining layer 

issues, Experiment K returned to the issue of 

the helmet lifting off the head when pressur-

ized. All previous methods used to hold the 

helmet down had worked to varying degrees 

when the suit was unpressurized, but all had 

eliminated mobility when the suit was pres-

surized due to tubular rigidity in the neck sec-

tion and the relatively weak neck muscles. For 

Experiment K, the fabric helmet had a “hole 

in the top” that eliminated lift and allowed 

the head to tilt forward, backward, and to 

either side. The helmet was built by molding a 

plexiglass hat band around the subject’s head, 

lining the inner circumference with 0.25-inchthick sponge rubber, and cementing a sheet of 

rubber over the sponge that extended about 

an inch below the bottom of the hatband. A 

fabric helmet with a plexiglass faceplate was 

fastened to the outside of the band.

Zippered plackets (slits) permitted the helmet 

to open to a sufficient size to allow the head to 

pass through while donning. When inflated, 

a seal was affected by pressure forcing the 

The Model 4A was perhaps 

the first truly workable 

David Clark suit. This is 

John Flagg wearing the suit 

in January 1951. Note that 

the gloves are an integral 

part of the suit, although 

the long zippers up the 

forearms eased the problem 

of donning the tight-fitting 

garment. Like many of the 

previous suits, the Model 4A 

used a soft helmet.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

192

rubber flap against the head. The rubber flap 

seal was prevented from being distorted by 

the snug-fitting, rigid hatband. Tests showed 

that the suit could be inflated to 2 psi with 

“remarkably good head mobility” and no 

helmet lift.19 The reason was that the head 

“plugged” the hole in the helmet, and the 

pressure within the suit, being greater than 

ambient, forced the head into the hole. 

Theoretically, researchers believed that given 

sufficient pressure the entire body could be 

squeezed through the hole—not a particularly 

pleasant thought. 

However, given the relatively low pressures 

used in the suit, the weight of the body, which 

in effect was being suspended by the top of 

the head, was enough to hold the helmet 

down. There was sufficient friction between 

the seal and the head to prevent the hatband 

from slipping off the head. It was a completely 

different answer to the problem. Despite the 

gains in mobility, neither David Clark nor the 

Navy continued this line of experimentation 

since the top of the head was unprotected 

(exposed to ambient atmosphere), and this 

might lead to unknown, and undesirable, 

physiological complications.

These experimental suits resulted in the 

Model 4 suit that was delivered to the Navy 

in September 1950. This suit used an outer 

restraining layer of open-weave nylon net fabric that allowed significant movement while 

unpressurized yet assumed the flying position 

when pressurized. The snug, lightweight fabric 

helmet allowed the pilot to wear a standard 

flying helmet over it for bump and crash protection. The helmet integrated a goggle-mask 

that sealed around the face, isolating this area 

from the rest of the suit. Unlike the Model 3, 

no external accessory straps were needed to 

combat helmet lift.

Initial tests at the NACEL were promising, 

and the Navy requested a second suit sized 

to fit Harry Weldon. While the suit was 

being fabricated, David Clark Company 

incorporated minor modifications to the 

respiratory system and added special fittings 

at the request of the laboratory, resulting 

in the Model 4A. In addition to various 

unpressurized evaluations, Weldon used 

the suit in a Link Trainer while inflated to 

3 psi. Overall, Weldon thought the suit was 

workable, but he offered several suggestions 

to improve the visibility, arm mobility, finger 

movement, and ventilation.20

By the beginning of 1951, the Navy was 

increasingly talking about using a full-pressure 

suit for an extended period, perhaps as the 

only life-support system in the aircraft. 

Officially, the garments were still considered 

“emergency suits,” but the definition of 

emergency now extended past simply getting 

the aircraft to a lower altitude; it now included 

completing the assigned mission. These were 

what the USAF called “mission completion” 

suits instead of “get-me-down” garments. 

As such, the suits required greatly improved 

comfort and mobility.21

There were avenues available to solve the 

mobility issues. In fact, the Germans and 

the Americans with some World War II era 

suits had already tried them: mechanical 

joints. The first location where David Clark 

used a mechanical joint was the shoulder. In 

all previous suits, the rotating action of the 

shoulder had been restricted, limiting arm 

mobility, particularly that required to reach up 

and pull the face curtain that activated many 

early Navy ejection seats. The answer was to 

install a thrust-type ball-bearing ring, with 

the arm of the suit connected to one race and 

the shoulder to the other. Since the company 

was unable to locate a suitable source for 

an airtight bearing, David Clark Company 

improvised by stretching the suit fabric over a 

non-airtight bearing. The Experiment L suit, 

which was otherwise similar to the Model 4, 

had ball-bearing shoulder and wrist joints on 

one side to allow a comparison with the fabric 

joints on the other side. The mechanical joints 

greatly improved the turning action of the 

hand and made it possible to rotate the arm 

fully. A further advantage was that each degree 

of rotation was neutral. Once the arm or hand 

was turned to a certain position, no additional effort was required to hold it in that 

position (unlike the normal suit, that always 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

193

The Experiment M suit, with the irreplaceable John Flagg 

inside, introduced metal bearings at both shoulders. The wrist 

bearings were substantially smaller than those introduced on 

the Experiment L suit. The bearings increased mobility, at 

least at the joints on which they were used, and only in a single 

axis, at a considerable increase in fabrication complexity. 

Courtesy of the David Clark Company, Inc.

wanted to return to its premade position). 

The Experiment L suit also used a new lighter 

weight material for the bladder. The designers 

hoped that the lighter material would improve 

mobility, but it was easily damaged and provided only minimal relief.22

Based on the apparent success of the ball 

bearing joints, Experiment M included 

bearings at both shoulders and wrists. The 

wrist bearings were substantially smaller than 

the ones used in the earlier suit and allowed a 

more natural use of the hands. A deliverable 

suit, Model 5, was fabricated to fit Harry 

Weldon, who tested it in the back seat of a 

Lockheed TO2 Shooting Star jet trainer.23

Weldon used the pressure suit at 1 psi for 

20 minutes in the first flight and at 2 psi for 

15 minutes in a second flight. The duration 

of the tests was not limited by the function of 

the suit but by the limited supply of oxygen 

aboard the trainer. Weldon reported that 

flying the airplane with the suit unpressurized 

presented no difficulties, and the movements 

required at 1 psi were possible without too 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

194

The Model 5 suit on January 31, 1951. One of the issues 

with Navy aircraft, in particular, is that naval ejection 

seats used pulling a face curtain down as the means of 

initiating an ejection. The handles the pilot used to grab 

the face curtain can be seen just behind the top of the helmet. 

Grabbing these handles required the pilot be able to move his 

arms up and back—a motion most early pressure suits did 

not allow while pressurized. This was less of an issue with Air 

Force ejection seats since they used handles between the legs 

or on the sides of the seats to initiate the ejection.

Courtesy of the David Clark Company, Inc.

much effort. However, at 2 psi, and the few 

minutes spent at 3 psi on the second flight, 

considerable effort was required to keep his 

right hand on the control stick. This was 

mostly because the type of test aircraft had 

not been known when the suit was made, and 

the neutral position for the arm did not align 

with the control stick. Although it was easy 

enough to correct the problem by revising the 

pattern for the suit, this presented a potential 

problem: If suits had to be made for each 

pilot for each type of aircraft he might fly, 

the number of suits could quickly get out 

of control.24

Weldon also complained that the mobility 

of his head was very limited, a known issue 

with all pressure suits. Weldon returned the 

Model 5 to David Clark Company with a 

request to improve head mobility. The designers decided to use the same ball-bearing concept on the neck as they had on the shoulders 

and wrist. This modification allowed the 

wearer to turn the head 52 degrees to each 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

195

The delivery of three Model 6 suits satisfied David Clark 

Company’s obligation under its original Navy contract. 

The waffle-weave fabric used for the restraint layer was 

the culmination of the research on knit fabrics dating back 

to the Experiment H suit. In this January 1951 photo, 

John Flagg is demonstrating the flexibility of the suit while 

it was unpressurized.

Courtesy of the David Clark Company, Inc.

side while unpressurized, 47 degrees at 1 psi, 

37 degrees at 2 psi, and 33 degrees at 3 psi. 

This was a substantial improvement but did 

not completely solve the problem. Since it was 

still difficult to nod the head up and down, 

David Clark Company continued to work on 

improved bearings, a better method of attaching the fabric, and reducing the amount of 

excess fabric necessary to accommodate the 

rotation of the bearing.

Although metal bearings satisfactorily solved 

the mobility issue for the shoulders and wrists, 

the elbows and knees did not lend themselves 

to that solution. Instead, designers turned to 

innovative fabric joints, some based on the 

lines of nonextension explained by Arthur 

S. Iberall. During the development effort, 

David Clark Company fabricated 25 different 

joints to test ideas. In the first experiments, 

the designers started out making the joint as 

simple as possible to provide a natural bending plane at the elbow. David Clark Company 

accomplished this by tying bands across the 

inside of the joint and integrating pieces of 

material to make creases. However, it immediately became obvious that breaking the wall 

force on the inner side, toward which the joint 

was bending, only solved part of the problem. 

It was also necessary to provide a means to 

lengthen the outer side. This can be readily 

observed by looking at one’s own elbow. With 

the arm straight, there is loose skin over the 

elbow bone. As the arm is bent, this is taken 

up until it is tight with the arm fully bent. As 

the joint is bent, the outside becomes longer 

and the inside shortens.

The designers at David Clark Company also 

experimented with bellows, or convoluted 

joints, much like the Project MX-117 “tomato 

worm” suits developed by Goodrich. These 

joints consisted of a tube tied with cords at 

intervals, forming a series of convolutions. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

196

While all the joints were bendable, there did 

not appear to be sufficient improvement to 

warrant their use. The obvious limitation 

to their greater ease of bending was that it 

was necessary to compress each of the convolutions on the inner side of the bend. A 

variation of the bellows joint used V-shaped 

convolutions that only encountered each 

other when fully compressed. This, however, 

pointed out a fallacy, or at least a limitation, 

with the rigid bellows joint—namely that 

there is a considerable resistance to bending 

because the circumference at the top of the 

joint is greater than at the bottom. When 

the joint is bent, these must equalize, requiring, in extreme cases, considerable effort. To 

overcome this, David Clark Company worked 

on a series of many-sided joints resembling a 

concertina, which demonstrated good flexibility but had a great deal of complexity and was 

difficult to manufacture.

While the convoluted joint proved disappointing, it gave the designers at David Clark 

Company another idea. By using a special 

nylon waffle-weave fabric, cutting it on a 

particular bias, and compressing and sewing 

it in a specific pattern, it was possible to 

create a cloth bellows joint that was lightweight, comfortable to wear, and reasonably 

simple to manufacture. Tests showed that the 

cloth bellows offered minimal resistance to 

bending at up to 5 psi, considerably better 

than previous efforts.25

The Experiment N suit used cloth elbow and 

knee bellows joints on one side only, along with 

the now standard shoulder and wrist rings. In 

a substantial change, the entire outer layer of 

the suit was sewn from the same nylon waffleweave fabric as the bellows joints. During tests 

in Worcester, these joints permitted extremely 

easy bending while pressurized at 3 psi.

Experiment P concentrated on improving 

the mobility of the head, and it returned to 

a dome helmet instead of the fabric helmet 

and faceplate. In this case, instead of a rigid 

plexiglass dome, David Clark Company constructed a dome made of rubberized fabric 

and flexible transparent plastic—essentially, 

it was a plastic bag placed over the head. A 

standard flying helmet could be worn inside 

the dome, there was no need to individually 

fit the domes to each pilot, it was easy to store, 

and it was not subject to breakage. Although 

a seemingly ideal solution, the head bag did 

not catch on.

David Clark Company delivered three 

Model 6 suits that were generally similar to 

Experiment N, all sized for Harry Weldon, 

to the NACEL. The inner gas-retaining 

bladder was made of neoprene-coated nylon 

fabric, and the outer layer used nylon waffleweave fabric. Fabric bellows joints were used 

at the elbows and knees, and ball bearing 

joints were used at the neck, shoulders, 

and wrists. The shoulder joints used new 

stainless-steel radial bearings that were much 

easier to turn than previous units.

The delivery of the 3 Model 6 suits fulfilled 

the requirements of the original contract to 

deliver 10 prototype pressure suits. David 

Clark believed that the Model 6 was a workable pressure suit and could serve as a prototype for production units. The Navy concurred 

that David Clark Company had fulfilled its 

obligations under its initial contract and, on 

August 1, 1951, awarded the company a new 

contract—NOa(s)-51-532c—for continued 

work.26 The contract requirements called 

for an omni-environmental suit that operated at 3.4 psi and had a leakage rate of less 

than 5 liters per minute. Almost immediately 

after the contract was issued, the need for a 

full-pressure suit became more urgent, primarily to support the Douglas D558 research 

airplane program and the Department of 

Defense afforded the development effort an 

“A” priority.27

The Douglas D558 program was the Navy’s 

3-phase answer to the USAF rocket-powered 

X-Planes. Like the Air Force efforts, the 

D558 program was a cooperative effort 

with the National Advisory Committee for 

Aeronautics (NACA). The phase one airplane, 

designated D558-1 Skystreak, was a jetpowered, straight-wing airplane intended to 

study the high-transonic flight regime, an 

area largely ignored by the Air Force effort 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

197

The first suit that David Clark Company delivered 

under their second Navy contract was the Model 7 for the 

Douglas D558 program. The suit used metal shoulder 

and wrist bearings, as well as convoluted bellows for the 

elbows and knees. The designers fabricated the restraint 

layer from a knitted waffle-weave fabric that offered a 

fair amount of flexibility while keeping ballooning and 

elongation to a minimum. 

Courtesy of the David Clark Company, Inc.

The Model 7 does not look out of place, even 60 years after it 

was first used. The knit fabric restraint layer was rather delicate, so an outer layer was worn to protect it from snagging 

on parts of an airplane. A standard crash helmet was worn 

over the fabric pressure suit helmet to protect the pilot’s head. 

Note the NACA wings on the helmet. 

Courtesy of the David Clark Company, Inc.

Although outwardly resembling the Model 6, the Model 7 

suit had the gas bladder and restraint layer sewn together 

into a single-piece garment. This photo shows the flexibility 

provided at the normal 3-psi inflation; note the bent arm 

and raised leg.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

198

but highly prized by the NACA. The three 

D558-1 airplanes eventually completed 

230 flights and set the last subsonic speed 

record. The phase two airplanes, designated 

D558-2 Skyrocket, were unique in the 

research airplane program since they included 

jet and rocket propulsion. The jet engine 

was useful for taking off from the ground, 

but was eventually removed and the D558-2s 

were carried aloft under the NACA P2B-1S 

(B-29) carrier aircraft, much like their Air 

Force counterparts. The three Skyrockets flew 

313 times and became the first aircraft to 

exceed Mach 2.

The first suit constructed under the new David 

Clark Company contract was a significant 

departure from previous efforts. Except for the 

Model 1, which had connected the bladder 

and restraint layer together into a single 

garment, all of the suits made on the earlier 

development contract had been two-piece 

designs consisting of separate bladders and 

outer restraining covers. This concept had 

presented several issues, most significantly 

making it difficult, and time consuming, to 

don the suit. The Model 7 was a single-piece 

suit that combined the bladder and restraining 

suits into a single garment by cementing 

0.020-inch-thick rubber sheet to the inside of 

the white nylon waffle-weave fabric used as the 

outer layer of the Model 6 suit.28 This was one 

of the first suits that Joe Ruseckas worked on, 

“banging metal” for the faceplate. Ruseckas 

would later become the head of research and 

development for David Clark Company.

This suit used the same neck, shoulder, 

and wrist bearings as the Model 6 suit, 

but it had molded, corrugated rubber 

sections at the knee and elbow joints. The 

garment completely enclosed the feet, and 

insulated boots were worn over the pressure 

suit. Originally, the rubber sheet was the 

innermost layer, but the friction of the 

rubber against skin made the suit difficult to 

don, so a thin layer of cloth was glued to the 

inside. The Eclipse-Pioneer Division of the 

Bendix Aviation Corporation manufactured 

the pressurizing regulator and the Firewel 

Corporation of Buffalo, NY, provided the 

breathing regulator. Tests in Worcester showed 

the suit was comfortable and allowed easy 

bending at the knees and elbows at 3 psi.29

The Model 7 holds a minor distinction: it was 

the first full-pressure suit that Albert Scott 

Crossfield wore. Crossfield was an engineer 

and NACA test pilot who would eventually 

accumulate more flight time in the rocket 

planes than any other individual, and he 

became a major influence in the development 

of the ultimate X-plane. Already a legend, in 

late 1951, Crossfield arrived, unannounced, 

at the NACEL seeking a suit that was better 

than the partial-pressure suit he had been 

using at Edwards. Harry Weldon showed him 

the Model 7 as “the most advanced thing 

The innovative fabric joints, some based on the lines of 

nonextension explained by Arthur S. Iberall, allowed the 

Model 7 to offer an acceptable amount of flexibility even 

when overpressurized to 4 psi. Despite the advances, 

the neck of the suit was still unacceptably stiff, and the 

metal shoulder bearings caused pain in the armpits. 

Nevertheless, the suit was deemed acceptable for the 

D558 flight tests.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

199

Seeking a more realistic test environment for pressure suits, 

engineers at Douglas Aircraft installed the cockpit from 

the prototype XF4D Skyray in a large altitude chamber 

at the El Segundo, CA, facility. The David Clark Model 7 

was among the first pressure suits evaluated in the test rig, 

which was representative of, but not identical to, the 

D558 research airplane. 

Courtesy of the David Clark Company, Inc.

we have.”30 Although it could never happen 

today, Crossfield convinced Weldon to let 

him try it in the altitude chamber, reaching 

90,000 feet. Crossfield was impressed, feeling 

the suit was far superior to the partial-pressure 

suit he was used to. Nevertheless, he felt it 

could be improved upon. As it turned out, 

this was the first time the Model 7 had been 

tested in extreme conditions, something 

Weldon had apparently neglected to mention 

to Crossfield. It was the beginning, as they say, 

of a beautiful friendship, with Crossfield and 

Weldon remaining in touch through the years.

Harry Weldon finally tested the Model 7 on 

November 12, 1951, at the NACEL. It took 

the Weldon 15 minutes to don the suit with 

the help of one assistant. The suit was pressurized to 4 psi for 1 hour, and Weldon reported 

that the shoulder bearings moved slightly 

outward under pressure, causing discomfort in the armpit. Knee and elbow bending 

were good, but neck mobility (turning) was 

poor. Shoulder rotation was adequate. Most 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

200

This photo provides an 

overall view of the Douglas 

altitude chamber. The circle 

on the floor represents the 

size of the altitude chamber; 

the cylindrical object at the 

top lowered to seal with the 

floor. The XF4D cockpit is 

sitting inside the chamber. 

Note that censors scratched 

out the image of the individual wearing the pressure 

suit seated in the cockpit because the suit was classified 

at the time. Scott Crossfield 

is on the extreme right with 

John Flagg and Joe Ruseckas 

behind him. 

Courtesy of the David Clark 

Company, Inc.
201

importantly, there was no ballooning, elonga-

tion, or lift, even at the higher pressure, and 

ventilation was adequate. A test on November 

15 determined the maximum pressure the suit 

would withstand; the pressure-sealing zipper 

failed at 7.75 psi, although it resulted in a 

slow leak, and the suit remained pressurized 

but required more air volume than before.31

By December 1951, the Navy and David 

Clark Company had tested the suit in flight 

and in altitude chambers up to 90,000 feet. 

However, it had not been through a rapid 

decompression of the type that most wor-

ried the designers of the D558-2. Researchers 

wanted to conduct the test in an actual cock-

pit to determine if the pilot could still operate 

the necessary controls during the decompres-

sion. The only facility that could conduct this 

type of test was the Douglas Aircraft plant in 

El Segundo, CA. Douglas engineers cut the 

cockpit section out of the prototype XF4D 

Skyray and installed it in a large altitude 

chamber. The cockpit could be pressurized 

while in the chamber, presenting a realistic 

surrogate to flying in a real airplane. The alti-

tude chamber, 11 feet in diameter and 7 feet 

high, consisted of a floor and a large cylindri-

cal section with a domed top that hydraulic 

cylinders could raise and lower to create an 

airtight enclosure. The chamber could be 

heated or cooled as needed and was capable of 

simulating altitudes up to 80,000 feet.32

The Model 7 suit controller 

was mounted in the back 

kit. The cylindrical ring 

around the outside of the 

back kit held emergency 

oxygen in case the pilot 

had to leave the aircraft 

at altitude. Developing a 

satisfactory suit controller 

was a major challenge 

during the 1950s.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

202

For the test, researchers used a Model 7 suit 

along with an improved Eclipse-Pioneer suit 

controller and a chest-mounted compensated 

breathing regulator designed by the Naval 

Aero Medical Equipment Laboratory (instead 

of the original Firewel unit). The first test put 

the unoccupied suit, pressurized to 3.4 psi, 

in the XF4D cockpit mostly to evaluate the 

test setup at altitudes up to 35,000 feet. The 

second test used an unoccupied suit during an 

explosive decompression. No damage to the 

suit was noted, so Harry Weldon participated 

in numerous rapid decompressions at altitudes between 24,000 and 67,000 feet. At 

the highest altitude, the decompression took 

2.67 seconds. In each case, the suit automatically inflated, maintaining an equivalent 

altitude of 35,000 feet, and Weldon suffered 

The Model 11 was another 

attempt to find a better solution for the helmet, this time 

using a flexible dome that 

was smaller than the Model 8 

rigid dome. Regardless, the 

dome needed to be large since 

a standard flying helmet 

was worn underneath it. 

John Flagg is wearing the suit.

Courtesy of the David Clark 

Company, Inc.

Above: Marine Corps Lt. Col. Marion Carl donning his 

Model 7 pressure suit inside a Boeing P2B-1S carrier aircraft 

on August 21, 1953. Carl would subsequently climb into the 

D558-2 and set an unofficial altitude record of 83,235 feet. 

Joe Ruseckas, behind Carl, was frequently onboard the 

P2B to assist the research pilots with donning their suits. 

U. S. Navy photo. National Archives College Park Collection 

via Stan Piet
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

203

Above: The Model 8 was mostly a minor evolution of the 

Model 7, but included a large dome helmet that greatly 

improved comfort and allowed a much better range of head 

motion. Unfortunately, the plexiglass dome was too large to fit 

into most fighter cockpits and was soon abandoned.

Courtesy of the David Clark Company, Inc.

The Model 11 back kit 

was also an evolutionary 

improvement over the 

one used on the Model 7. 

Emergency oxygen was still 

carried in the outer frame, 

with the suit controller and 

breathing regulator in the 

center area. A standard 

parachute was worn over the 

back kit.

Courtesy of the David Clark 

Company, Inc.

Some of the molds used to 

make the rubber parts of the 

gas bladder for the Models 

11 and 12 full-pressure 

suits. At the rear is a hand 

mold for the gloves, and to 

its right are the elbow and 

knee bellow molds.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

204

The Model 12 returned to a 

normal soft helmet, although 

this one included an integral 

set of goggles that were 

hinged at the top and could 

be opened when the suit 

was not pressurized. This is 

the suit with the protective 

outer cover installed. Note 

the pilot is wearing normal 

dress shoes.

Courtesy of the David Clark 

Company, Inc.

no ill effects and felt he was quite capable of 

piloting the airplane.33

After this, five rapid-decompression and four 

explosive-decompression tests were run at various altitudes up to 65,000 feet with Richard J. 

McGowan, Jr., of the NACEL in the cockpit. 

Each event took between 0.75 and 1.84 seconds to completely depressurize. At no point 

during these tests did the suit pressure drop 

below the specified 3.4 psi, and the relative gas 

expansions of the subject were well within safe 

limits. During the decompressions, McGowan 

reported feeling a small amount of air escape 

from his lungs, a momentary feeling of pressure as the suit stiffened, and, in a few cases, a 

brief feeling of dizziness.34

The Navy did not intend these tests to 

evaluate the comfort or mobility of the suit. 

However, both Weldon and McGowan 

reported that the suit was comfortable and 

sufficiently flexible when unpressurized. They 

also reported that the suit was sufficiently 

comfortable when pressurized except around 

the oral-nasal mask seal. Weldon wore the 

suit continuously for 3 hours and underwent 

three rapid decompressions without undue 

fatigue. The suit did restrict mobility when 

pressurized, especially around the neck, but 

it appeared to be possible to fly the airplane. 

Nevertheless, the Navy researchers felt that 

the suit was unsuitable for operational use, 

although it was adequate for use in experimental research airplanes such as the D558.35

Almost concurrently with the Model 7, David 

Clark Company constructed the Model 8, 

which used a bladder made of fabric rubberized on only one side along with the restraining layer made of nylon waffle-weave fabric. 

The two layers were made from the same 

pattern and joined together so they could be 

donned as a single garment. This suit included 

a new type of dome head enclosure consisting 

of a hard plastic front section with clear soft 

plastic portions in the rear quarters and upper 

forward portion. A standard flying helmet and 

oxygen mask were worn inside the dome, with 

a rubber neck seal to isolate the dome section 

from the rest of the suit. The new head enclosure offered almost unlimited visibility but 

was extremely large and did not fit inside the 

cockpits of most contemporary fighters.36

The Model 9 and Model 10 suits were essentially similar to the Model 7 using different 

fabrics (a waffle-weave Dacron for the Model 

9 and rubberized nylon tricot for Model 10). 

Both suits were sized to fit Weldon and were 

delivered to the NACEL in December 1951. 

The Model 11 was similar to the Model 8, 

with a flexible dome head enclosure, but it 

had a better overall fit and was easier to don. 

It featured one-piece construction, with a 

lightweight fabric rubberized on one side only 

(uncoated fabric toward the body) and nylon 

waffle-weave, seamed together. The waffleweave cloth provided the necessary strength 

and tended to prevent elongation; the rubberized fabric of the gas-retention bladder was 

stretchable. The dome head enclosure was 

similar to the Model 8 and featured a rigid 

plexiglass front portion. It also used a soft flexible transparent plastic on the forward portion 

of the top and the rear quarters for upward and 

peripheral vision. A rubber neck seal isolated 

the dome from the rest of the suit. Donning 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

205

Like many of the early David Clark suits, the Model 12 was 

a tight-fitting garment with little visible difference between 

its unpressurized (left) and pressurized (right) appearance. 

A variety of zippers made the Model 12 easier to don, and 

more zippers provided limited size adjustments, although the 

suit was specifically tailored to fit Scott Crossfield. The metal 

shoulder and wrist bearings are visible, as are the elbow- and 

knee bellows joints.

Courtesy of the David Clark Company, Inc.

occurred through a 42-inch pressure zipper 

extending vertically from the lower back to the 

head enclosure. Ball-bearing joints were used 

at the neck, shoulders, and wrists, with fabric 

knee and elbow bellows as in the Model 7.37

Crossfield’s quest became official shortly after 

his visit to Philadelphia. On August 13, 1951, 

Ira H. Abbott, the NACA assistant director 

for research, wrote to Maj. Gen. Frederick 

R. Dent, Jr., the commander of the Wright 

Air Development Center (WADC). Abbott 

requested the Air Force provide a full-pressure 

suit for Crossfield’s flights in the D558-2, as 

well as the Bell X-2 and Douglas X-3. However, at this point, the USAF was still pursuing 

partial-pressure suits and did not have a fullpressure suit it could supply to Crossfield. 

This did not deter Crossfield, and he traveled to Worcester to meet David Clark. Scott 

Crossfield described Clark as “a stocky man 

of about fifty-five, with bushy eyebrows and 

delicate hands which, like his mind, seemed to 

always be in high-speed motion.”38 Crossfield 

left with yet another new friend. When he got 

back to Edwards, Crossfield wrote a letter to 

NACA headquarters in Washington recommending that the NACA encourage the Navy 

effort with David Clark.

On October 23, 1951, John W. Crowley, the 

NACA Associate Director for Research, wrote 

to the chief of the Navy Bureau of Aeronautics 

requesting a full-pressure suit for Crossfield. 

Crowley pointed out that allowing Crossfield 

to use a suit would provide “a useful field test 

of the equipment.” Interestingly, long before 

lawyers influenced every facet of American 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

206

life, Crowley said, “The NACA is aware that 

the omni-environmental suit is still in its 

development stage and expects the Bureau of 

Aeronautics to accept no responsibility in the 

event of malfunction or failure of the unit.”39 A 

week later, J.E. Sullivan from BuAer responded 

that the Navy would provide Crossfield a 

suit on indefinite loan and requested that 

Crossfield make himself available as needed 

for fittings at Philadelphia or Worcester. Harry 

Weldon and David Clark redoubled their 

efforts, despite a serious lack of funding.

The concept of a pressure suit was finally 

maturing. In November 1951, the NACEL 

requested David Clark manufacture two suits, 

both similar to the Model 7, for use in the 

experimental research airplane program at 

Edwards. The Model 12 suit was tailored 

to fit Crossfield, who needed the suit for 

continued testing of the D558-2. The 

Model 12 used a rubberized Lastex40 inner 

suit and a nylon waffle-weave outer suit 

joined at the same seams so it was, in effect, 

a one-piece suit. A transverse pressuresealing zipper, located on a line just below 

the armpit, circumvented the chest except 

for approximately 5 inches in the center 

front. There was also a vertical back zipper 

running from the buttocks up to the 

horizontal zipper. Adjustment zippers 

were located on the back of the calves and 

wrists. The suit used neck, shoulder, and 

wrist bearings designed at the NACEL 

that were machined to finer tolerances, 

making for smoother operation. Even David 

Clark Company admitted these were an 

improvement over previous efforts. The suit 

was tested in Worcester to 5 psi with minor 

leakage that was soon corrected.41

The Model 12 was taken to Edwards on 

December 10, 1952, so that Crossfield could 

evaluate it in the cockpit of the D558-2. After 

ingressing and egressing from the airplane several times, Crossfield decided the suit did not 

interfere with any normal or emergency functions he might need to perform. David Clark 

had brought two different close-fitting helmets, and Crossfield decided that both designs 

had worthy features but that neither was satisfactory. Accordingly, David Clark Company 

took the best features of both and created a 

new helmet that consisted of a facemask with 

a seal around its periphery that isolated the 

wearer from the gas used to pressurize the suit. 

The mask had two parts—the goggles and 

the respiratory mask—separated by a molded 

rubber partition that helped reduce fogging 

of the goggles. A 2.5-inch diameter cover over 

the mouth could be removed when oxygen 

was not needed. An airtight fabric cover was 

cemented around the facemask and connected 

to the suit at the neck ring.42

The gloves also caused adverse comment from 

Crossfield. The D558 had numerous small 

buttons and toggles located on the control 

wheel, and these proved difficult to manipulate 

with the existing gloves. David Clark Company had been working on a set of partialpressure gloves, but given the 4-psi operating 

pressure of the new suits it appeared best to 

abandon those efforts and concentrate on a 

new set of full-pressure gloves. The company 

began looking at how it would incorporate the 

concepts used in the knee and elbow joints in 

the relatively small area of the fingers.43

Scott Crossfield wore the Model 12 suit when 

he took the second D558-2 (BuNo 37974, 

NACA 144) to 1,291 mph on November 20, 

1953, becoming the first man to exceed 

Mach 2, albeit in a slight dive from 62,000 

feet. William B. Cassidy from the Navy Aero 

Medical Equipment Laboratory (AMEL) and 

Joe Ruseckas from David Clark Company 

were in the P2B-1S to help Crossfield don 

the suit.44

The Model 13, the second of the suits based on 

the Model 7, was tailored to fit Marine Corps 

Lt. Col. Marion E. Carl. A World War II ace, 

Carl was the last man to set a world’s speed 

record under the speed of sound while flying 

the jet-powered D558-I Skystreak. During 

August and September 1953, Carl would 

make six attempts to set speed and altitude 

records using the Model 13 pressure suit in 

the second D558-2. The first launch, on 

August 13, was cancelled before the airplane 

was dropped from the P2B-1S because of a 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

207

The Model 16 used a waist gusset that could be closed to 

control elongation while the pilot was seated or it could be 

opened to allow the pilot to stand erect as shown here. A 

pressure-sealing zipper running circumferentially around the 

chest just under the armpits allowed donning and doffing. 

The neck, shoulder, and wrist bearings were built into the 

restraint layer and were not part of the pressure bladder.

Courtesy of the David Clark Company, Inc.

One of the more unusual 

tests conducted on pressure 

suits was this visor 

windblast evaluation. The 

pilot, strapped into an 

ejection seat, was suspended 

over an icing chamber that 

blasted high-velocity air at 

the visor. Note the frost on 

the goggles. Similar tests 

were run with warm air.

Courtesy of the David Clark 

Company, Inc.
208

The Model 18 was another 

attempt to provide a large 

dome that could cover a 

standard flying helmet and 

oxygen mask. The pressure 

suit itself incorporated 

many improvements and 

evaluators were generally 

impressed with the flexibility 

and comfort. Like the 

attempts before it, the size of 

the helmet proved a major 

impediment to the suit’s use 

in operational aircraft.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

209

bad disconnect in the oxygen system that 

topped off the rocket plane’s oxidizer tank. 

The third, on August 21, set an unofficial altitude record of 83,235 feet. Carl’s last flight, on 

September 2, established a new military 

speed record of 1,143 mph (Mach 1.728) at 

46,000 feet. On all of these flights, Cassidy, 

Crossfield, and Ruseckas assisted Carl in 

donning the suit in the PB2-1S. Carl noted 

that it was impossible for the pilot to don or 

doff the suit without assistance and said he 

carried a knife “for the express purpose of 

cutting his way out should the circumstance 

arise.”45 Fortunately, it never did.

Crossfield and Carl each followed largely 

the same procedures during their D558 

flights. Immediately after the P2B took off, 

the research airplane pilot shed his clothes 

and donned a set of long underwear. 

Cassidy and Ruseckas helped the pilot don 

the pressure suit and helmet. At about 

7,000 feet, the pilot climbed into the D558-2 

and Cassidy and Ruseckas connected the 

oxygen, radio, and electrical leads. By the 

time the bomber reached 10,000 feet, a crew 

chief closed the canopy, and the research 

airplane pilot began waiting. Five minutes 

prior to drop, the pilot began his prelaunch 

checklist. Once the D558 was dropped, 

the pilot ignited the no. 3 chamber of the 

Reaction Motors XLR11 rocket engine, 

followed by chambers 4, 1, and 2.46 Besides 

setting several records, the Skyrocket pilots 

gathered important data and understanding 

about stable, controlled flight of a sweptwing aircraft in the transonic and supersonic 

flight regimes. Like all of the early research 

airplanes, their primary value was establishing 

a better correlation of windtunnel test results 

with actual flight data. 

Carl provided a lot of feedback on the suit: 

After the suit was properly fitted, two and 

a half days were spent at AMEL in indoctrination to the wearing and functioning 

of the suit. As the suit fitted almost skin 

tight, the first problem was fighting off 

claustrophobia, which turned out to be 

quite an item when the pilot became 

too warm. After the first couple of times 

in the suit, this was never again of any 

consequence. In addition to the present schedule for indoctrination, which 

includes both Link Trainer time with suit 

inflated and deflated, a run to 80,000 feet 

in the chamber, and a couple of explosive 

decompressions, it is felt that a flight in a 

TO-2 with the pilot flying with the suit 

inflated for a short time would have been 

of definite value.47

He felt the biggest issue with the suit was temperature control; Carl was either too hot or 

too cold, although he was usually too hot. He 

thought better ventilation, particularly around 

the head, arms, and legs, would solve this 

problem. Even when the suit was deflated, the 

pilot could not see the instruments and controls on the rear half of the side consoles. The 

head could only be turned about 45 degrees 

and could only be tilted down slightly. Carl 

complained that mobility, particularly when 

the suit was inflated, was very limited. Movement of the arms and legs was particularly 

restricted, and it was difficult to climb into 

or out of the cockpit. Carl commented he 

“was continually annoyed by his inability to 

grasp and feel things properly.”48 The gloves 

were too slick and too cumbersome, and Carl 

wanted a larger faceplate and tinted glass to 

reduce glare. Finally, he thought the weight 

and size of the back kit—25 pounds and 

5 inches thick—was excessive. Despite the 

criticisms, Carl concluded that the suit was 

“satisfactory for continued flight use as an 

interim measure pending improvements, 

and that it is the best suit for high altitude 

research flights now available.”49

The Model 14 was essentially a Model 12 

sized to fit Charles C. Lutz of the USAF Aero 

Medical Laboratory at Wright Field as part of 

an exchange of ideas relating to pressure suits. 

The Model 15 was a similar suit intended for 

LCDR Roland A. Bosee at the NACEL, but 

the suit was cancelled before it was completed 

for unexplained reasons.50

By March 1952, David Clark Company had 

developed a completely airtight shoulder 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

210

bearing that eliminated some of the manufacturing issues with the original cloth-covered 

ball bearing units, but the company was 

unable to incorporate the change into the 

Crossfield and Carl suits because of timing. 

David Clark Company had also simplified 

the construction of the cloth knee and elbow 

bellows joints without sacrificing mobility and 

had begun experimenting with insulating the 

outer layer of the pressure suit with reflective 

foil. The Minnesota Mining and Manufacturing Company, later called 3M, was developing 

a special technique to coat the spun-nylon 

waffle fabric with a silver metallic layer.51

Unfortunately, the Navy contract ran out 

of funds in April 1952, effectively ending 

large-scale development work on full-pressure 

suits at the David Clark Company. The Navy 

found sufficient funds to continue a minor 

effort at David Clark Company, resulting in 

continued support for the couple of suits used 

at Edwards and for the fabrication of several 

derivative suits for further research.

For example, on July 7, the NACA HighSpeed Flight Station at Edwards requested 

several changes to Scott Crossfield’s Model 12 

suit. These included new arm sections, different zippers, redesigned disconnect and check 

valves for the breathing regulator, the relocation of the breathing regulator, a redesigned 

helmet lens, and the manufacture of a special 

parachute pack and harness. David Clark 

Company completed these changes in September 1952, and the Navy tested the suit in the 

NACEL altitude chamber in October 1952.52

The Model 16, sized to fit LCDR L. Harry 

Peck from the NACEL, incorporated some of 

the changes recommended by Marion Carl. 

David Clark Company delivered the suit to 

the Navy on January 12, 1953. The suit consisted of a rubberized fabric inner bladder, a 

nylon waffle-weave outer restraining garment, 

and a nylon outer coverall. A pressure-sealing 

slide fastener opened circumferentially around 

the chest, and a waist gusset allowed the 

suit to be configured for standing or sitting 

by opening or closing a nonpressure sealing 

zipper on the outside of the suit. Rotatable, 

nonpressure sealing rings were located at the 

neck, shoulders, and wrists. The close-fitting 

Right and page 211: The torso of the Goodrich Model H 

used reinforced rubber-impregnated fabric with pleated 

fabric over the rubber pressure convolutes and was an 

intermediate step in the evolution from earlier suits that 

used all rubber-impregnated fabric construction. Note 

the helmet pressure regulator over the mouth is unlatched 

and hanging by the pressure supply hose. The upper torso 

retention/anti-elongation straps are unthreaded from the 

upper attach buckles. The Air Force evaluated the Navy 

suit in the XB-58 cockpit mockup in Fort Worth on 

April 27, 1954. 

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

211

headpiece used a pressure-sealing slide fastener, a removable faceplate, and a manually 

accessible oronasal opening. The suit weighed 

16 pounds without the Firewel combined 

compensated regulator or other accessories.53

The Navy tested the Model 16 in Philadelphia 

and using the XF4D cockpit in the Douglas 

altitude chamber. The evaluators noted 

that exhaling took noticeable effort when 

the suit was unpressurized, the intensity 

of which depending upon the tightness of 

the straps, the tightness of the parachute 

harness, and how the suit fit. Using a Link 

Trainer in Philadelphia, researchers noted 

that downward and aft vision was poor, the 

gloves were still too smooth and slippery, and 

the wrist rings inadvertently touched various 

switches in the cockpit. At 1 psi inflation, 

it was extremely difficult to move the neck, 

shoulder, and wrist bearings and it became 

nearly impossible to move these bearings at 

3 psi. In the XF4D cockpit, the evaluators 

noted, “only straight and level flight could be 

accomplished,” and the pilot could not reach 

the ejection face curtain when the suit was 

pressurized.54 The Model 16 did not include a 

ventilation garment, and the evaluators noted 

excessive perspiration after extended wear. 

Despite the apparent failings of the Model 

16 to meet operational requirements, the suit 

provided satisfactory physiological protection 

under all conditions, including explosive 

decompressions up to 53,000 feet.
The Model H helmet used a retractable visor and a 

form-fitting headpiece with a crash-protection shell that 

was permanently attached to the torso garment. Unlike 

some later Goodrich helmets, the visor retracted on top of 

the pressure shell instead of into a protective pocket. Note 

the lace adjustments between the gloves and sleeves. One 

of the major objectives of the April 1954 evaluation was 

to determine if the crewmember could reach all of the 

controls in the XB-58 cockpit. 

Courtesy of Lockheed Martin Aeronautics
Initially, the Air Force considered a full-pressure suit 

mandatory for the Convair B-58 Hustler because of its 

altitude and speed capabilities. However, the generally 

unsatisfactory evaluation of the several pressure suits 

that existed, along with a decision to use self-contained 

escape capsules that could protect a crewmember in an 

emergency, eventually led to pressure suits not being used 

in the aircraft. 

National Archives College Park Collection
214

The Goodrich Model L was generally similar to the earlier 

Model H but had a detachable helmet. In this case, the 

pilot used a separate oxygen mask inside the helmet. Perhaps 

the major external change was that most of the reinforced 

rubber-impregnated fabric used on the Model H was replaced 

by lighter and more flexible fabrics. 

U.S. Navy

The Model 17 was a development suit dedicated to fabric shoulder joints instead of the 

metal bearings used in earlier suits. Researchers 

found that these joints were somewhat easier 

to fabricate but provided no better mobility.55

Model 18 was an entirely new suit sized to fit 

John E. Flagg, the director of Research and 

Development at the David Clark Company. 

The suit included structural modifications that 

made it easier to don, pressure-sealing shoulder bearings, a redesigned ventilation system, 

improved glove construction, and a flexible 

dome that enclosed a standard-issue flying helmet. The suit was demonstrated at the David 

Clark Company facility in Worcester on January 14, 1953, observed by CDR Kenneth 

Scott and LT Frank Blake from the NACEL.56

Joe Ruseckas delivered the Model 18 to the 

Navy on April 16, 1953, but the NACEL 

performed only a cursory evaluation of the 

suit since it did not fit any of their personnel. 

Comments included that the gloves afforded 

relatively good feel and mobility and the visor 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

215

defogging system was adequate. The mobility of the suit was good when it was unpressurized and only moderately impaired when 

pressurized to 3 psi. The new ventilation 

system appeared adequate at room temperatures and up to 75 oF. The suit survived being 

pressurized to 4 psi without failure, although 

the pressure-sealing shoulder bearings leaked 

excessively and rusted.57

The Navy evaluators thought that developers 

should concentrate on several areas to improve 

future models of the suit. Primarily, the wrist 

bearings should be replaced by forearm bearings to eliminate the potential for inadvertent 

switch actuation, and the shoulder bearings 

should be improved to eliminate leakage. In 

addition, the pressure-sealing zipper should 

be modified to make it watertight in addition 

to being airtight. Other suggestions included 

designing a helmet to eliminate the need to 

wear an oxygen mask and moving the breathing regulator so it was not be mounted on the 

chest. Lastly, any future suit should include a 

restraint layer that better controlled ballooning. Still, the Navy acknowledged that progress was being made.58

Because of this demonstration, the Navy 

ordered a Model 19 suit sized to fit LT Frank 

Blake. The suit was essentially the same as the 

Model 18 but with a revised facemask and a 

helmet sized to fit a McDonnell F2H Banshee, 

a typical Navy fighter of the era. John Flagg 

and Joe Ruseckas took the Model 19 to 

NATC Patuxent River, MD, on January 18, 

1954, for tests in a Douglas F3D Skyknight, 

selected because of its large cockpit.59

RUSSELL COLLEY, AGAIN

For unknown reasons, at the same time the 

David Clark Company was running out of 

funds on its contract, the Navy awarded a 

development contract to B.F. Goodrich in 

Akron, OH. Goodrich was well qualified 

to develop a pressure suit, having done so 

for Wiley Post in 1935 and for the Army 

during World War II. The primary Goodrich 

engineer for the effort, Russell Colley, was 

one of the few legends in the business. Later, 

when the National Aeronautics and Space 

Administration (NASA) selected a modified 

Navy-Goodrich suit for Project Mercury, 

Colley would leave Goodrich and join the 

space agency. Over the course of his career, 

Colley received 65 patents and NASA awarded 

him a Distinguished Public Service Medal 

in 1994. Retiring from NASA, he returned 

to northeastern Ohio, where he became a 

watercolor painter and jewelry designer. Russell 

Colley passed away on February 4, 1996, in 

Springfield, OH.60

The first suit to evolve from the Goodrich 

contract, the Model H of 1952, looked 

much like the pressure suits the David Clark 

Company was developing and, for that matter, 

the wartime suits various contractors developed 

for the Army. It is not clear why this suit was 

called the Model H, but interestingly, Colley 

had developed seven suits for the Army during 

World War II, and “H” is the eighth letter.

The Model H helmet, gloves, and boots were 

permanently attached to the suit torso. The 

torso construction of the Model H, consisting 

of reinforced rubber-impregnated fabric and 

pleated fabric over rubber pressure convolutes, 

was an intermediate step in the evolution 

from earlier Goodrich suits that had used all 

rubber-impregnated fabric construction. The 

later Model S (which was produced in limited 

numbers as the Mark I) eliminated the outer 

rubber coating, making a lighter and more 

flexible (when unpressurized) suit. 

The Model H helmet used a retractable 

visor, a form-fitting headpiece with a crashprotection shell, and a breathing regulator on 

the facemask.61 Colley and his assistant project 

engineer, Stephen C. Sabo, adopted the same 

technique used by David Clark for vulcanizing material to provide elasticity, strength, and 

stability. Goodrich developed airtight bearings 

that could be used at the shoulders and wrists, 

as well as semirigid accordion pleats for the 

knees and elbows. Although Goodrich did not 

intend the Model H to fulfill all the requirements for an operational suit, initial testing 

was promising. Researchers at the NACEL 

evaluated the suit at 60,000 to 80,000 feet 
178

The Goodrich Model S already exhibited several features 

that would find their way onto the ultimate Navy Mark IV 

full-pressure suit. The most obvious was the entry zipper that 

ran diagonally across the chest. Of interest is the figure-eight 

helmet-tiedown system that ran from the crotch, behind the 

back, under the armpits and to the helmet. Russell Colley also 

designed a helmet that was divided into two sections by a face 

seal, eliminating the need for a separate oxygen mask.

U.S. Navy

for 11 hours, and its performance indicated it 

might be well suited as a mission completion 

suit instead of just a get-me-down suit.62

In January 1954, the USAF Aero Medical 

Laboratory met with representatives of the 

Bureau of Aeronautics and the NACEL to dis-

cuss emerging USAF requirements for a fullpressure suit for the Boeing B-52 Stratofortress 

and Convair B-58 Hustler. The Navy agreed to 

accelerate its program with a goal of delivering 

an experimental suit to the USAF in June 1954 

at a cost of $244,000. The Aero Medical Labo-

ratory was skeptical of this schedule, doubting 

that sufficient development work could be 

completed by the date suggested by the Navy. 

Nevertheless, Air Force Headquarters trans-

ferred $130,000 to the Navy for five suits to 

be delivered “not later than 1 June 1954,” just 

over 4 months in the future.63

In early April 1954, the USAF evaluated a 

Model H suit in the XB-58 cockpit mockup. 

According to the Air Force, the suit lacked 

mobility, was uncomfortable, had restricted 

vision, inadequate ventilation, poor landsurvival qualities, and was difficult to don and 

doff. It is interesting to note how two different 

groups—the Air Force and the Navy—can 

evaluate the same product and come to 

very different conclusions. Some of this was 

undoubtedly parochial since the USAF, really 

wanted to develop its own full-pressure suit, 

but some of it is also just different priorities 

and perceptions. By September 1954, it was 

obvious that the Navy effort would not pro-

duce a suit that was acceptable to the USAF 

and the Air Research and Development Com-

mand ordered the Aero Medical Laboratory to 

develop an independent design to fulfill USAF 

requirements. This announcement was made 

in the course of a joint pressure suit develop-

ment symposium held in Philadelphia on 

February 1–3, 1955.64

In the meantime, a breakthrough came in 

1952 when a team at the Firewel Company, 

headed by Edward Meidenbauer, developed 

an automatic suit controller that precisely 

controlled pressurization and oxygen content. 

Previously, the pilot had needed to adjust the 

pressurization as he ascended or descended. 

Since the Navy expected to use the pressure 

suit in aircraft that rapidly climbed to high alti-

tude, researchers concluded there was no need 

to dilute the oxygen flow at lower altitudes. 

With the need for dilution eliminated, as was 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

217

the need for positive pressure, a simplified 

miniature regulator was possible. Goodrich 

and David Clark Company both adopted the 

controller for all future suits. The controller 

was, in essence, an aneroid-controlled backpressure valve that maintained the pressure 

suit at the equivalent of 35,000 feet (3.5 psi) 

regardless of the actual altitude of the airplane. 

Researchers believed that using 35,000 feet as 

a control altitude was an advantageous compromise of the mobility difficulties of a fully 

pressurized garment with the physiologic considerations of hypoxia and aeroembolism. At 

this suit altitude, the pilot could function normally, breathing 100 percent oxygen without 

pressure breathing.65

Concurrent with the development of Model 

H, the NACEL began explosive decompression studies of humans. Subjects using the 

Model H were decompressed from altitudes 

as high as 75,000 feet in as little as 110 milliseconds. Researchers were surprised to find 

no immediate or residual pathological effects. 

This was because the suit acted as a buffer during the decompression. Although the chamber 

altitude went from 18,000 feet to 75,000 feet 

in 110 milliseconds, it took 3 seconds for the 

suit to deflate from 18,000 feet to 35,000 feet, 

where the subject was maintained.

The Model L was a modification of the 

Model H that used a detachable headpiece 

to make it easier to don.66 The suit weighed 

25 pounds, and the pilot needed to use a 

separate oxygen mask under the plexiglass 

helmet. Despite any perceived limitations, 

in April 1953, LCDR Harry Peck from the 

NACEL demonstrated the suit in an altitude 

chamber at 70,000 feet.67 By now, the Navy 

was highlighting that the B.F. Goodrich fullpressure suit was, in fact, a “spacesuit” that 

could operate in a vacuum.

The Navy realized that other components of 

the pilot life-support system would have to 

be improved to support a workable pressure 

suit, and it assigned the development of these 

components to three contractors. The Aerotec 

Company was assigned the problem of developing a composite disconnect, Firewel continued working on regulating equipment, and 

the Ralph E. Darling Company investigated 

suitable connecting hoses.68 Despite the progress made by all involved, at the end of 1953, 

many Navy researchers believed, “the fullpressure suit looked like an insurmountable 

problem for application to high performance 

weapons systems.”69 Development continued 

in any case.

The Model M of 1954 was a significant 

advance that used the newly developed 

Firewel automatic suit controller and eliminated the oxygen mask. Almost all previous 

pressure suits had used an oral-nasal oxygen 

mask inside the helmet to reduce potential 

dead air space in the helmet and permit visor 

defogging. However, the use of the mask limited visibility and proved uncomfortable for 

the wearer. The one concern about eliminating 

the separate mask was that too much carbon 

dioxide (CO2

) would build up in the helmet 

as the pilot exhaled. Physiological studies conducted at the NACEL determined that CO2

buildup in the headpiece cavity was within 

tolerable limits. The Model M also incorporated detachable gloves to make donning and 

doffing easier.70 No records could be located 

to describe the Model N through Model Q, 

if such suits existed.

The Model R featured the ability to sit-standsit while pressurized and zippers that allowed 

the suit to be fitted to individuals. Wire palm 

restraints kept the gloves from sliding off the 

hands when they were pressurized, and the 

helmet allowed supplementary tinted lenses to 

be installed if needed. Tests revealed that the 

Model R was relatively comfortable and provided sufficient mobility, but several problems 

remained before the suit could be produced for 

fleet use. The bearings in the joints were sealed 

against air escaping from the inside but not 

against water leaking in—not an ideal trait if 

one parachutes into the ocean. The boots were 

unsatisfactory, and, as with many pressure-suit 

designs, the helmet continued to lift unacceptably under pressure. The Model R, and 

all previous Goodrich suits, used an internal 

helmet tiedown harness that proved unsatisfactory since once the harness was adjusted and 
218

The Goodrich Mark III 

suit was a major step 

forward in developing an 

operational full-pressure 

suit. Interestingly, the pilot 

is holding a Mark II helmet, 

identifiable by the visors 

rotating under a protective 

cover rather than on top 

of the helmet. Note that 

the boots used a single side 

zipper instead of laces.

U.S. Navy

the suit donned, the pilot could not adjust 

the helmet. In addition, to keep the helmet in 

place, the harness had to be tightened to such 

a degree that it proved uncomfortable to wear 

for any prolonged period.71

MARK I

Russell Colley and the Goodrich team took 

the Model R and began to modify it to make 

it watertight and improve the helmet tiedown 

system. At the same time, they decided to 

incorporate detachable boots to provide more 

sizing options and improve comfort. Colley 

also began to research ozone-resistant materials that would provide a longer life and require 

less maintenance for an operational suit.72

The resulting Model S differed from the 

earlier Model R in that it used the diagonal 

“Sam Browne” pressure zipper-entry configuration (as opposed to the U-shaped Model R 

entry configuration). The Model S was the 

first to employ zippers for glove attachment 

(Model R had a piston-ring-type latch), and 

the suit featured detachable pressure boots and 

zippered sizing bands in the arms and legs. 

Seven rotary-bearing joints aided mobility at 

the expense of excessive bulk and weight. 

The Model S used a helmet tiedown system 

consisting of steel cables that passed from the 

headpiece through the crotch in a figure-eight 

design. Altitude chamber tests showed the 
219

system prevented the helmet from rising under 

pressure, but the cable tension across the buttocks was uncomfortable to many wearers. As 

a side benefit, the new nylon restraint materials and streamlined fittings gave the suit a 

more esthetic appearance.73

A ventilation-insulation garment worn next 

to the body was followed by a cutaway G-suit. 

The two-layer pressure suit, with a rubberized 

airtight and watertight liner and a syntheticfabric restraining layer, was worn over the 

G-suit. Flotation gear was integrated with the 

parachute harness, and the pressure-control 

equipment and emergency oxygen supply were 

carried in a back kit74 or seat kit, depending 

on the aircraft type being flown.75

The interior of the helmet was divided into two 

sections by a face seal. The forward section was 

pressurized with breathing oxygen while the 

back section was open to the rest of the suit. 

Oxygen flowed through perforations in a tube 

installed circumferentially around the visor 

to reduce fogging of the visor. Oxygen was 

delivered to the forward section at 1.8 mm Hg 

above suit pressure to overcome possible faceseal leakage. One-way valves passed exhaled 

gases into the interior of the suit.76

Despite not being completely pleased with the 

new helmet tiedown system, in 1954 the Navy 

in 1954 ordered the Model S into limited production as the Mark I Omni-Environmental 

The Mark III-LW was 

a major modification to 

the basic Mark III design. 

The lightweight suit used 

a smaller helmet ring and, 

hence, a smaller helmet. 

Note the parachute torso 

harness, life preserver, and 

bailout backpack.

U.S. Navy
178

The Mark III-LW was a major step toward an operational 

full-pressure suit. Note the pressure-relief fitting on the 

lower left leg has been capped off for this test. A variety of 

interesting suits is hangs in the background, and a Mercury 

suit is on the table.

U.S. Navy

Suit. The suit stretched 30 inches across the 

shoulders and weighed 26 pounds, making 

it awkward to cram into the cockpit of a jet 

fighter. Goodrich produced the suit in only 

three sizes, essentially ensuring that it fit 

nobody particularly well. The Navy conducted 

operational evaluations in the Vought F8U-1 

(F-8A) Crusader, and not surprisingly, pilot 

feedback centered on the overall bulk and 

weight of the suit, the restrictions imposed by 

the shoulder bearings, and the discomfort of 

the helmet tiedown cables on the buttocks.77

By June 1954, the Navy had supplied several 

Mark I suits to various aircraft manufactures. For instance, Grumman chief test pilot 

Selden A. “Connie” Converse used one while 

testing the F11F-1 Tiger.78

MARK II

The Mark II was a somewhat lighter, slightly 

reconfigured version of the Mark I. This was 

probably the most flexible of the Goodrich 

suits, providing very reasonable mobility. 
179

LCDR Richard H. Tabor, MC, USN, in the long underwear 

he wore during a series of 1958 long-duration tests using a 

Mark III, Mod II suit. Long John underwear with Trilok 

spacer panels was worn under all Navy pressure suits, as 

well as the Mercury suits. The Trilock panels provided a 

noncompressible mesh that was used where the pressure suit 

would be in tight contact with the body to ensure airflow was 

maintained. It was also used at the location of the exhaustport fitting to ensure the port was not blocked.

U.S. Navy

The helmet, in particular, was innovative and 

served as the inspiration for several David 

Clark Company helmets that followed. The 

retractable clear visor used a pneumatic seal 

around its perimeter that inflated automatically as it was lowered. The breathing regulator was located on the left side of the helmet 

and included an “ON-OFF” oxygen control 

and a visor-seal deflation button. An adjustment knob for sizing the internal straps and 

pads that held the face seal against the face 

was located on the right side of the helmet. 

The clear and tinted visors retracted upward 

into an enclosed space intended to provide 

protection against scratching.79

The Navy, however, was still concerned about 

the overall bulk and 23-pound weight of the 

Mark II, and it found that the shoulder bearings and helmet tiedown cables continued 

to cause discomfort. Although several dozen 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

222

suits were fabricated for evaluation, ultimately, 

the Navy decided to trade some mobility for 

greater comfort and lighter weight.80

MARK III

The Mark III traded the mobility of the 

Mark I and Mark II for reduced bulk and 

weight. Colley accomplished this by deleting 

six of the rotary bearings, eliminating the 

bulky detachable pressure boots, and using 

lighter weight fabrics. 

The way the Navy pursued pressure suit 

development was somewhat different from the 

Air Force and was reminiscent of how G-suit 

development progressed. Although the Navy 

had a research and development contract with 

Goodrich, that did not necessarily mean that 

Goodrich would be the company that actually manufactured production suits. As the 

NACEL and Goodrich perfected a part of the 

suit, the Navy developed requirements that 

reflected the design and incorporated these 

requirements into a procurement specification. 

The Navy then released this specification to 

industry and awarded production-development 

contracts to qualified bidders.81

In the case of the Mark III full-pressure suit, 

the specification required the suit to provide 

a 35,000-foot equivalent atmosphere for 

the pilot and a minimum of 25 minutes 

of emergency oxygen. The suit had to 

withstand, without damage, ejection at 

Mach 1 at 35,000 feet and provide pilot 

ventilation, cold-water immersion protection, and flotation.82

When the Navy released the bid for the 

Mark III suit, two companies responded: 

Goodrich and the Arrowhead Products 

Division of Federal-Mogul-Bower of 

Los Alamitos, CA. Arrowhead, under the 

leadership of research and development 

manager H. Wendall Nuttall, dubbed its 

suit, “garment, upper stratosphere” (GUS).83

Each company presented a design that met 

the requirements established by the Navy. 

Both were lightweight models with compact 

suit-control systems and simple disconnects. 

The Goodrich suit weighed 10 pounds and 

the Arrowhead suit 9.5 pounds, compared 

to 23 pounds for the Mark II suit. The 

Goodrich suit measured 26 inches across the 

shoulders while the Arrowhead suit measured 

27 inches, compared to 30 inches for the 

Mark II. Other improvements included a 

reduction of 0.9 pound in the life preserver 

and 1.25 pounds in the helmet and the 

installation of a safety pressure-relief valve 

on the suit.84

Despite the relative success at addressing the 

deficiencies in the Mark II suit, the helmet 

neck area continued to present a problem in 

terms of both development and pilot acceptability. Possible solutions, none of which was 

incorporated on either Mark III suit, included 

a dome-type helmet design, cut-down neck 

rings, and mounting the breathing regulator 

internally.85 Nevertheless, Lester M. Snider, the 

BuAer supervisor of the Mark III project, said 

the suit was, “less expensive, less fatiguing to 

wear, more mobile, easier to maintain, and far 

easier to put on and take off than any other.”86

It was more an indictment of pressure suits in 

general than an endorsement of the Mark III.

The Navy selected the Goodrich Mark III suit 

for limited production, although it also procured small quantities of the Arrowhead suit 

for fleet evaluation. The Goodrich suit consisted of optional waffle-weave thermal underwear, a ventilation garment that distributed air 

through ducts at the wrists and ankles, a modified Z-3 G-suit, and a pressure garment that 

came in sage green, silver, and gold lamé. The 

helmet, gloves, and boots were detachable. 

The suit controller and oxygen supply could 

be worn as a seat kit or a back kit, depending 

on the aircraft being flown.87

The Mark III helmet had both clear and 

tinted visors mounted on top, rather than 

under a protective cover as on the Mark II, 

allowing the helmet to be somewhat lighter 

weight. An inflatable pressure seal around the 

helmet opening acted upon the clear visor. 

The breathing regulator was on the left side of 

the helmet and included an on-off valve and a 

button that deflated the visor seal. A knob on 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

223

the right side of the helmet controlled the tension of the internal straps and pads, allowing 

the pilot to adjust the helmet without removing it. A face seal separated the breathing space 

from the rest of the helmet and suit. As on 

the Mark II helmet, oxygen flowed over the 

visor through a series of perforations in a tube 

installed around the perimeter. A microphone 

and headphones were built into the helmet, 

which weighed just less than 5 pounds, about 

2 pounds less than the Mark II. The helmet 

provided the same level of crash protection as 

the standard Navy flight helmet.88

Goodrich also produced a lightweight 

Mark III suit that used a smaller and lighter 

neck ring. This allowed a smaller and lighter 

helmet, reducing the weight that the pilot’s 

neck needed to support.89

On July 25, 1957, Lt. James D. LaHaye, 

a test pilot with Air Development Squadron 

Three (VX-3) from Naval Air Station (NAS) 

Atlantic City, N.J., was testing an early 

F8U-1. The flight, intended to collect 

zoom-climb performance data, became a 

real-world emergency when the Pratt & 

Whitney J57 turbojet experienced a 

flameout at 52,000 feet. At that point, 

the Mark III suit LaHaye was wearing did 

exactly what it was designed to do: it 

inflated. Despite the relative discomfort, 

LaHaye immediately descended and 

began the air-start procedures as he passed 

through 35,000 feet, with the engine finally 

coming back to life at 30,000 feet.90

After the flight, LaHaye reported the suit did 

not overly restrict his movements while pressurized, that he had no difficulty flying the aircraft, and the suit did not restrict visibility. “In 

the uninflated condition, the visibility afforded 

by the suit was far better than I had anticipated. Since the back kit of the full-pressure 

suit moves the pilot forward, I expected to have 

difficulty in seeing the switches on the after 

parts of the consoles. But I found that I could 

see and reach all necessary switches.”91 LaHaye, 

however, did find that the bulk of the straps 

and other items at the shoulders had an adverse 

effect on mobility of the helmet because it 

restricted the movement of the neck ring.

LaHaye continued, “My overall impression 

of this suit as compared to the partial-pressure 

suit is that it has very little less mobility, visibility, and comfort in the uninflated condition. In the inflated condition, it is much 

more comfortable and affords much more 

mobility and visibility than an inflated partialpressure suit.”92 A recurring theme of pressure 

suits is that pilots frequently find fewer faults 

with the garments during actual emergencies than they do during routine evaluations. 

Credit the adrenaline. 

In 1958, a 36-year-old naval flight surgeon, 

LCDR Richard H. Tabor, wearing a 

Mark III suit, was exposed to simulated altitudes between 30,000 and 170,000 feet for 

3 days. This experiment showed that pilots 

could tolerate pure oxygen at 35,000 feet for 

72 hours, that the Mark III suit was tolerable 

at extremely high altitudes for extended 

periods, and that humans could function in 

such an environment with negligible physiological or psychological deterioration. 

Tabor spent 76 hours and 48 minutes in the 

suit, including more than 33 hours above 

90,000 feet.93 The Navy was making a case 

for a spacesuit. 

Similarly, on April 14, 1958, LTJG William J. 

Pfister wore a Mark III suit when he entered 

an altitude chamber at NAS North Island, 

CA, and spent 16 hours in a cockpit mockup 

at 80,000 feet. A week later, LTJG Arthur F. 

Vohden spent 24 hours in the same chamber 

and lost 5 pounds in the process. During these 

tests, the pilots conducted a series of exercises, 

including head and arm movement and operating flight controls. Physiologists monitored 

their heart rate, blood pressure, respiratory 

data, and temperature. On the East Coast, 

LCDR Jack Neiman, Jr., conducted similar 

tests at NAS Norfolk, spending 44 hours 

at chamber altitudes between 80,000 and 

110,000 feet.94

In addition to protecting a pilot at high altitude, the Mark III suit also had to protect 

him if he was forced to abandon his aircraft. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

224

The major components of 

the Goodrich Mark IV fullpressure suit. Missing from 

the photo are the outer fabric 

cover, suit regulator (which 

was a separate component), 

one earphone assembly, and 

one outer glove cover-layer 

assembly. At the lower left of 

the photo is a complete suit 

side neck ring along with all 

the components that make 

up the neck ring.

U.S. Navy

To demonstrate the insulation properties 

of the suit, in 1958 NACEL civilian technician Richard J. “Dick” McGowan spent 

45 minutes in a tank of freezing brine with 

an air temperature of −40 oF above him. 

He indicated he never felt cold. During 

an altitude chamber test, McGowan spent 

11 hours at 80,000 feet.95 Experiments like 

these undoubtedly influenced the NASA decision to use the B.F. Goodrich suit as the basis 

for the initial Project Mercury spacesuits.

In the summer of 1958, four pilots from 

Naval Air Test Center Patuxent River wearing 

Mark III suits made seven flights from the 

USS Forrestal (CVA-59). These pilots—

LCDR F.H. Austin, Jr., LCDR A.J. Nemoft, 

LCDR Richard Jester, and Marine Corps Maj. 

Roy C. Gray— were performing carrier qualifications for the F8U-1. A secondary purpose 

was the evaluation of pressure suit aboard an 

aircraft carrier. Ultimately, between mid-1957 

and mid-1958, Navy pilots made more than 

180 sorties wearing Mark III suits. Based on 

this limited experience base, in 1958, ADM 

Arleigh A. Burke, the chief of naval operations, made wearing pressure suits mandatory 

for flights above 50,000 feet.96

Although all Forestall-class supercarriers had 

air-conditioned readyrooms, it quickly became 

evident that additional ventilation was needed 

for the pressure suits. In response, the Navy 

developed conditioned air supply equipment (CASE) that could provide air in the 

readyroom for up to 20 pressure suits. During 

1958, the USS Ranger (CVA-61) became the 

first aircraft carrier to have a pressure suitfriendly readyroom installed. This room also 

contained larger chairs to accommodate pilots 

in the bulky pressure suits, and each chair had 

connections to the CASE that the pilot could 

plug into.97
179

Looking every bit like a spacesuit, this variant of the Mark IV 

was an early Mercury suit in front of an altitude chamber at 

the McDonnell Aircraft Company facility in St. Louis, MO.

NASA

The carriers were also equipped with airconditioned dressing rooms where the 

temperature was maintained between 75 and 

80 oF with a relative humidity of 45 to 

55 percent. Body temperature problems were 

greatly reduced by this cool, dry atmosphere 

while the pilot was donning his suit. The 

dressing rooms also provided space for 

pressure-suit drying and stowage. Since each 

pilot required assistance while donning the 

suit, the rooms were large enough for eight 

seated persons (the pilots) and eight standing 

assistants. The Navy subsequently modified 

all frontline attack carriers to accommodate 

pressure suits, and all future Forestall class 

carriers were built with the accommodations.98

The A.J. Sawyer Company, under contract to 

the Bureau of Weapons, developed portable 

air-conditioning equipment that could venti-

late a suit as needed at shore installations or on 

aircraft carriers not equipped with built-in sys-

tems. These 16-pound portable, battery-driven 

refrigeration units could be used by pilots 

walking from the readyroom to their aircraft 

and by pilots waiting in their aircraft if no 

shore air was available. David Clark Company 

provided similar units for the Air Force suits. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

226

Providing adequate 

ventilation for the wearer 

of a pressure suit has always 

proved to be challenging. 

Goodrich used a multiple 

exhaust-valve system that 

moved air across the entire 

body, thereby preventing 

excessive perspiration.

Courtesy of the David Clark 

Company, Inc.

TAC Trucks served a similar function and pro-

vided an air-conditioned vehicle to transport 

pilots from the readyroom to their aircraft at 

shore installations. Each 1.5 ton truck could 

accommodate eight pilots.99

In addition, Grumman manufactured eight 

portable air-conditioned readyrooms, all 

delivered by May 1961 for temporary use 

at locations lacking permanent pressure-suit 

facilities. Each consisted of two side-byside 40-foot aluminum trailers that were 

connected at one end. Four men could set up 

the facility in 10 hours. The dressing room 

trailer contained storage lockers, toilet and 

shower facilities, a drinking fountain, hot 

water heater, and special storage facilities for 

the pressure suits. The briefing and alert room 

trailer contained 16 tilt-and-swivel chairs 

fitted with small tables, chalk and display 

boards, and a CASE system for the pilots to 

connect to while waiting.100

In March 1959, the Navy issued Mark III 

suits to the VF-142 Flying Falcons aboard 

the USS Ranger (CVA-61). The fighter squadron, flying F8U-1 Crusaders, was the first to 

make a carrier deployment equipped with fullpressure suits.101

Although the company was the also-ran 

in terms of production, Arrowhead gained 

national attention for its Mark III suit in 

1958 when it was featured on the cover of 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

179

This Week, a national newspaper supplement. 

In January 1959, the suit appeared in a tenminute segment of the You Asked For It television show. A few months later, a facsimile of 

the suit made another appearance. At the time, 

space themes were popular in Hollywood, 

and the various producers wanted authenticlooking spacesuits. Arrowhead, David Clark 

Company, and Goodrich all declined offers to 

provide movie props, probably afraid to upset 

their military sponsors. Sometime in 1959, 

however, Arrowhead relented and created 

the Garment, Upper Hollywood (GUH), 

which was worn by actor Lee Marvin in the 

“Man in Orbit” episode of the Westinghouse 

Desilu Playhouse television show. The episode 

was based on a story by James E. Gunn that 

had appeared in the February 1955 issue of 

Galaxy Magazine. The suit was largely identical 

to a production Mark III but lacked the 

more expensive features that made it a “real” 

pressure suit.102

MARK IV

The Mark III suit was the culmination of the 

Navy’s search for a lightweight full-pressure 

suit. However, service trials uncovered a variety 

of issues, including numerous reliability and 

wearability problems. In response, the Navy 

decided to ease the weight requirements in 

hopes of getting a more robust garment. The 

NACEL developed the requirements for the 

Mark IV suit under the direction of CAPT 

W.L. Jones, CAPT Roland A. Bosee, Lee Snyder, and James V. Correale.103

Much as it had with the Mark III, the Navy 

released the requirements for the Mark IV for 

bid. The same two companies, Arrowhead and 

Goodrich, responded. Both companies were 

awarded development contracts and both suits 

proved satisfactory. Once again, Goodrich 

received the majority of the production order, 

although a limited number of Arrowhead 

suits were also procured. At Goodrich, Wayne 

Galway led the development effort.104

The Mark IV consisted of the torso, helmet, 

gloves, and boots. The two-layer torso was a 

closely fitted coverall encompassing all of the 

body except the head, hands, and feet. The 

shoulder, upper arm, and wrist sections did 

not use bearings but provided mobility by 

means of Helenca knit stretch fabric tailored 

into the inner layer of the suit around the 

NASA Marshall Space Flight Center Director Wernher 

Von Braun leaving a suiting-up van wearing an Arrowhead 

AE-83 version of the Navy Mark IV pressure suit, prepared 

for a tryout in the MSFC neutral buoyancy simulator. 

Interestingly, Von Braun is wearing Goodrich helmet and 

gloves with the Arrowhead suit. Weighted to a neutrally 

buoyant condition, Von Braun was able to perform 

tasks underwater, which simulated weightless conditions 

found in space.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

228

shoulder, arms, and crotch. The inner airtight layer used neoprene-coated fabric and 

coated Helenca fabric in stretch areas, with 

cold-cemented seams. The suit was entered 

through a pressure-sealing zipper located on 

the diagonal across the chest extending over 

the shoulder and terminating approximately 

3 inches below the shoulder cap. Goodrich 

had used this entry method on several previous suits and pilots had found it preferable to 

rear entry. The inner layer of the neck section 

was made of neoprene-coated Helenca fabric 

and the outer layer was nylon fabric to provide 

strength. The 9.5-inch-diameter neck ring 

provided the attachment point for the helmet 

and contained a breathing regulator and communication system.105

The arms and legs were tailored to reduce 

bulk and the outer ply of these sections used 

pleated construction to facilitate mobility 

and a nylon adjustment strap for sizing. 

These straps channeled along the sides of 

the arms and legs and were patterned to give 

a reasonable fit from the 5th to the 95th 

percentile of the male pilot population. The 

gloves extended from the lower one-third of 

the forearm to the fingertips, and the boots 

extended from the upper one-third of the 

lower leg to the bottom of the foot. Sock 

endings for the legs were made of nylon 

Helenca fabric with a thin ply of neoprene 

gum. The socks were permanently attached 

to the inner layer of the suit.106

The gloves used neoprene-coated fabric and 

coated Helenca fabric in stretch areas along 

with leather palms. A restraining wire bent to 

fit the hand prevented the palm of the glove 

from ballooning under pressure. The gloves 

were available in 15 sizes, consisting of 5 palm 

sizes with short, regular, or long fingers. The 

gloves attached using sealed disconnects 

secured by a slide-fastener zipper.

There were four port fittings located in the 

upper torso below the left and right armpits: 

the anti-G fitting at the left front, ventilationgarment fitting at the left rear, suit exhaust at 

the right front, and pressure-sensing line at 

the right rear. Some later Mark IV suits had a 

direct-reading altimeter on the left thigh.

The Mark IV helmet was generally similar to 

the Mark III unit. The helmet was constructed 

from phenolic resins and fiberglass cloth and 

was designed to offer maximum visibility, 

comfort, mobility, windblast protection, 

crash protection, and simplicity of operation. 

It had an internal suspension system and a 

built-in AIC-10 communication system. The 

retractable visor was made of Plex II Plexiglas 

and used a pneumatic seal when closed. A 

retractable tinted lens blocked 83 percent of 

the visible light to provide glare protection. A 

face seal separated the breathing space from 

the pressurization section using a wide, soft 

rubber seal mounted to a soft aluminum 

frame that could be bent to conform to the 

symmetry of the face. The helmet used a 

Firewel GR-90 demand-type oxygen regulator.

The helmet holddown system consisted of a 

cable-and-pulley arrangement that prevented 

rise under maximum suit pressure and permitted side-to-side movement up to 3.5 psi. 

The suspension system included a midsection 

and two side tiedowns that provided a “sitstand” feature. To stand from a sitting position 

required releasing the midsection tiedown 

buckle, thus releasing the webbing restraint 

and permitting elongation of the torso. The 

midsection webbing was tightened when the 

pilot was seated.107

Goodrich provided special underwear with 

each suit. The cotton underwear had three 

Trilok patches, one on the right side of 

the torso and one above each thigh, which 

prevented the ventilation system from being 

blocked by the underwear. The operating 

instructions included a warning that this 

was the only type of underwear that could 

be used. Accessories included an integrated 

floatation garment with parachute harness. 

The pilot wore a standard cutaway G-suit 

when needed.108

The Mark IV suit was fitted to each individual through a selection of properly sized 

components and the adjustability features of 

the torso. The torso was supplied in 12 stock 

sizes consisting of 6 chest sizes in either short 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

179

Apparently, the Navy suit could be used in Air Force 

aircraft. This is CDR Forrest S. Petersen in a Goodrich 

Mark IV next to JF-104A (56-749) carrying an Air 

Launched Sounding Rocket (ALSOR) on February 16, 

1961. Petersen was an X-15 pilot and was well familiar 

with the contemporary David Clark Company MC-2 

full-pressure suit. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

230

or long based on the relationship between the 

expanded chest circumference and the vertical 

trunk length. The torso could be somewhat 

tailored using length-adjustment straps and 

circumferential lacing.109 The suit weighed 

20 pounds.110 In all, the close-fitting, silvercoated Mark IV was every boy’s dream of 

what a pressure suit should look like, much 

more so than the more successful David Clark 

Company suits.

Under normal conditions, with the cockpit 

adequately pressurized, the Mark IV was 

unpressurized except for ventilation airflow 

supplied by the aircraft’s air-conditioning 

system. The air flowed through a series of 

Trilok ducting that was integral to the torso 

and exited at the wrists, ankles, crotch, and 

periphery of the neck ring. It then flowed into 

the body of the suit to remove excess moisture 

and exited the suit through the exhaust port, 

into the cockpit. In addition to ventilating the 

suit, this air also pressurized it when needed. 

When cockpit pressure fell below 3.5 psi 

(35,000 feet), the suit immediately pressurized 

using the ventilation air. If the ventilation air 

was also lost, the suit pressurized using breathing oxygen. In the event of bailout, the emergency oxygen supply pressurized the suit and 

provided breathing oxygen. Because the suit 

provided adequate physiological protection, 

there was never a need for pressure breathing.111

A pilot could survive under water for 5 minutes 

by breathing the oxygen trapped in the suit.112

The Mark IV was used operationally in the 

McDonnell F4H Phantom II (F-4), Douglas 

F4D Skyray (F-6), Vought F8U Crusader 

(F-8), and North American A3J Vigilante 

(A-5). On December 6, 1959, the Navy used 

a McDonnell F4H-1 (F-4A) Phantom II to 

set an altitude record of 98,560 feet. The 

pilot, CDR Lawrence E. Flint, was wearing 

a Goodrich Mark IV suit. Pilots complained 

that excessive pressure built up while the 

suits were ventilated but unpressurized. A 

new controller helped but did not eliminate 

the problem. Goodrich developed new flow 

valves that went a long way toward curing 

the problem, but it is unclear when they 

were introduced into operational suits. 

Nevertheless, the Navy used the Mark IV 

operationally far more extensively than 

the Air Force did with the David Clark 

Company suits. Despite its apparent success, 

the operational career of the suit was 

short-lived.113

As it had for the Mark III, Arrowhead 

developed and manufactured an alternate 

Mark IV suit. By March 1960, the Navy 

had qualified the Arrowhead AE-83 suit 

but had not ordered sufficient quantities 

to declare it operational. Despite many 

reports, the Arrowhead and Goodrich 

Mark IV suits were not identical. Each 

was the result of a separate development 

effort to meet the requirements imposed 

by the Navy.114

Although the suits generally resembled each 

other, there were some significant differences in how they performed. For instance, 

the Aviation Medical Acceleration Laboratory (AMAL) studied how well pilots could 

reach the ejection seat controls while wearing 

pressure suits in the Johnsville centrifuge. 

The AMAL researchers concluded that the 

Goodrich Mark IV suit was more flexible and 

more comfortable to wear (especially across 

the shoulders), had a more natural head position when the suit was inflated (since the head 

was erect instead of pitched forward), and 

was easier to size and adjust. The Arrowhead 

AE-83 offered easier head movement when 

the suit was unpressurized; the one-layer glove 

was easier to don; the single, large spiral zipper made it easier to close than the zippers on 

the Goodrich suit; and the “Iron Age” boots 

supplied by Arrowhead were more rugged 

and provided better support during parachute 

landings and hiking.115

The laboratory concluded that neither suit 

provided sufficient ventilation even on the 

highest setting. Each suit also suffered from 

the absence of any protection for the trailing 

edge of the visor while in the up position, 

frequently resulting in the failure of the pivot 

connection while pulling the ejection-seat face 

curtain down over it.

In the end, the researchers at AMAL decided, 

“there is no apparent difference in the 
179

NASA selected a modified version of the Goodrich Mark IV 

pressure suit as the Mercury spacesuit. Note the clear plastic 

protectors covering the boots.

NASA

obstruction offered by the Goodrich and 

Arrowhead full-pressure suits when they were 

not inflated.” This was not as comforting as it 

sounded since the researchers also concluded 

that both suits reduced “the probability 

that a pilot will be able to eject successfully 

in a Martin-Baker seat equipped with an 

integrated harness.” In addition, the study 

showed, “inflation of the full-pressure suit 

further reduces the probability of a successful 

ejection.”116 This study, although not greatly 

affecting pressure-suit development, since 

the Navy abandoned the operational use of 

pressure suits soon thereafter, was the impetus 

for the Navy moving from the face curtain 

actuation method to ejection controls located 

on the seat arms or between the pilot’s legs.

MARK IV SUITS FOR STRATO-LAB

During the late 1950s and early 1960s, the 

Navy sponsored the Project Strato-Lab highaltitude balloon program under the direction 

of CDR Malcolm D. Ross. Strato-Lab sought 

to obtain fundamental data in astronomy, 

atmospheric physics, and human physiology 

at high altitudes. One set of experiments dem-

onstrated that protons from solar flare activity 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

232

International Latex Corporation (ILC) submitted this 

SPD-117 full-pressure suit in the Mercury competition. As 

with the Air Force MC-2 competition, ILC was significantly 

behind the power curve, and the suit placed a distant third 

in the NASA evaluation. Nevertheless, it proved a learning 

experience for the company, and later versions of this suit 

design eventually went on to win the Apollo suit competition. 

U.S. Air Force photos.

Courtesy of the Terry Panapolis Collection

posed a serious risk to humans working in 

space, contributing to methods of predicting 

and monitoring solar flare activity. Strato-Lab

also contributed to early astronomical observations above the bulk of Earth’s atmosphere.117

The program made five flights from the 

flight deck of the USS Antietam (CV-36), 

based at NAS Pensacola, FL. The carrier 

maneuvered to create zero wind across the 

deck to simplify launching the missions. The 

10,000,000-cubic-foot balloon used pressurized and unpressurized gondolas and culminated in a record-setting flight on May 4, 

1961, by Ross and LCDR Victor A. Prather, 

Jr., to test the Mark IV suit. The 9-hour, 

54-minute flight set an altitude record of 

113,740 feet and covered a horizontal distance 

of 140 miles. Ross and Prather were exposed 

to temperatures as low as −137 oF as they 

passed 53,000 feet and experienced an ambient pressure of 5 mm Hg (0.09 psi).118

As they descended, the balloonists opened 

their visors as they passed below 15,000 feet. 

Strato-Lab V landed in the Gulf of Mexico. 

According to a suit technician on the scene, 

“The water landing was routine and soft, with 

three helicopters hovering over them. Ross 

stepped out of the gondola, sat on the seat lowered to him, and was hoisted into a helicopter. 

Prather stood on the seat, and when about 

25 feet above the water, he fell. He floated on 

his back, and then started thrashing wildly to 

get to the gondola. He became tangled in the 

parachute shroud lines. The diver dove from 

the helicopter and cut Prather loose from 

the shroud lines. Prather sank about 10 feet 

below the surface before the diver got him and 

brought him to the surface. The ship put out 

a boat and brought them aboard.”119 Unfortunately, LCDR Victor Prather had drowned.
233

Despite the tragic loss of Victor Prather, Ross 

thought the suits performed well: “The suits 

surpassed our highest expectations with flying 

colors.”120 President John F. Kennedy posthumously awarded Victor Prather the Navy 

Distinguished Flying Cross for “heroism and 

extraordinary achievement” and the balloonists were awarded the 1961 Harmon Trophy 

for Aeronauts. The flight is still the FAI altitude record for a manned balloon flight.

The USAF procured a limited number of modified Goodrich Mark IV suits as the A/P22S-3, 

to equip fighter squadrons based in colder 

parts of the country.121 It is unclear exactly 

how many suits were procured and if they were 

actually issued to operational squadrons.

MARK V

Several references have mentioned a Mark V 

suit developed in 1967, but no further 

description could be found.122

PROJECT MERCURY SPACESUITS

Although most history gives that the Mark IV 

was the predetermined basis for the NASA 

spacesuits used on Project Mercury, the story 

is actually a bit more complex. Initially, the 

Mercury capsule was going to provide a shirtsleeve environment with only a G-suit for the 

astronaut, much like that envisioned for many 

of the high-performance military aircraft of 

the era. However, by February 1959, 

Maxime A. “Max” Faget from the Space 

Task Group at the NASA Langley Research 

Center and USAF aeromedical specialist 

Lt. Col. Stanley C. White became convinced 

that an alternate plan would be required 

based on the difficulties being encountered 

with designing the environmental control 

systems for the capsule.123

Faget and White believed that the pressure 

suits being developed by the military could be 

modified to support Mercury. NASA held the 

first pressure suit conference at Wright Field 

on January 29, 1959, and more than 40 companies sent representatives. NASA requested 

that the USAF Aero Medical Laboratory and 

the Naval Air Crew Equipment Laboratory 

conduct an evaluation of available pressure 

suits to be completed by July. Throughout the 

spring, the established pressure-suit vendors—

David Clark Company and B.F. Goodrich—

supported the development of requirements 

and evaluation criteria, which were published 

by NASA on March 10, 1959.124

A team led by Charles C. Lutz and 

Dr. Edwin G. Vail at the USAF Aero 

Medical Laboratory at Wright Field spent 

approximately 5,700 man-hours between 

June 1 and July 4, 1959, evaluating suits 

and documenting them with over 9,000 feet 

of color movie film and 160 still photos. 

The David Clark Company, B.F. Goodrich, 

and the International Latex Corporation 

(ILC) provided suits for the evaluation.125

David Clark Company delivered its suit on 

June 1, 1959, and the USAF noted a few 

discrepancies during the initial evaluation, 

primarily that the leak rate was high, mostly 

around the neck ring. The suit, made with a 

liberal use of Link-Net, performed well in the 

altitude chamber tests, with subjects indicating that comfort and mobility were adequate. 

The suit had not been tailored specifically for 

any of the evaluators, and a custom-tailored 

garment would have been more comfortable and ballooned somewhat less. The suit 

provided excellent protection against extreme 

environments (cold), although the evaluators 

thought an extra pair of socks and better ventilation was needed.

The durability and reliability of the David 

Clark Company suit was supported by the lack 

of any serious failures during the evaluation. 

Lutz and Vail noted that, “most of the Clark 

suit features which caused loss of points in the 

scoring system are easily correctable without 

additional research and development.”126 One 

possible exception was the shape of the helmet. 

David Clark Company had provided a cylindrical visor instead of the specified spherical 

shape, based on comments from engineers at 

McDonnell Aircraft where the Mercury capsule was being developed. The evaluators also 

thought the method for attaching the gloves to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

234

Perhaps one of the more 

famous pressure suit photos 

was this July 1962 shot of 

the Mercury Seven. Front 

row, left to right, are Walter 

M. Schirra, Jr., Donald K. 

Slayton, John H. Glenn, Jr., 

and M. Scott Carpenter. 

Back row, left to right, are 

Alan B. Shepard, Jr., Virgil 

I. Grissom, and L. Gordon 

Cooper, Jr. All are wearing 

Goodrich “quick fix” suits 

based on the Navy Mark IV.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 5: Navy Full-Pressure Suits

235

be very good, although they wanted a bearing 

that was more easily operated.

Russell Colley delivered the B.F. Goodrich 

suit on June 17, 1959. Initial testing showed 

the suit had an exceptionally low leak rate. 

Unpressurized, the Mark IV was considered 

comfortable, and the plethora of straps and 

laces could be overcome by custom-fitting the 

suits to each astronaut. Comfort when the 

suit was pressurized was considered adequate. 

Environmental tests showed the suit had very 

poor ventilation, and Lutz and Vail did not 

think the existing design could be modified 

to correct the deficiency. The helmet shell 

and visor failed under pressure tests, and the 

evaluators believed the helmet needed to be 

redesigned. The helmet also required highpressure (70 psi) air to seal the visor, and 

this was not expected to be available on the 

Mercury capsule.

ILC delivered its SPD-117 (the 117th 

design—not all pressure suits—from the 

Specialty Products Division) suit on June 1, 

1959. This suit contained several component 

parts that the company acknowledged as 

inadequate but were the only ones available 

within the allocated schedule. These included 

adjustment laces and joint bellows that had 

not been designed for this application. Largely 

because of inadequate development, the suit 

was judged too uncomfortable: it leaked excessively, and was unreliable. The restraint cable 

in each shoulder failed during testing, ultimately terminating the test early since there 

was insufficient time to correct the anomaly.127 

Lutz and Vail concluded that the suit from 

David Clark Company “most nearly meets all 

the requirements established by Project Mercury”128 and demonstrated the best durability 

and reliability. The researchers believed, however, that all of the deficiencies noted in the 

Goodrich and ILC suits could be corrected 

given sufficient time.

A second conference was held at Langley on 

July 15, 1959, where the chairman, Richard 

S. Johnston from the Space Task Group 

indicated that NASA would continue working 

with David Clark Company and Goodrich 

to refine its suits. This, however, did not 

happen. Instead, for unexplained reasons, 

NASA announced on July 22, 1959, that 

the Goodrich Mark IV would serve as the 

foundation for the Mercury spacesuit. 

Russell Colley, Carl F. Effler, and Donald 

D. Ewing at Goodrich would lead the 

development effort.129

It was not a bad decision, just unexpected. 

The Navy always intended that the Goodrich 

suits would be suitable for use in a vacuum, 

and the Mark IV suit was designed specifically with that requirement. The Navy 

required that the suit be capable of operating 

at 7 psi, although the normal operating pressure was 3.5 psi, with an alternate setting of 

5 psi (27,000 feet). Researchers realized they 

would need to provide facilities and modifications to permit eating while in the suit. 

However, Navy researchers believed the “suit 

system can be matched to orbital and space 

missions with respect to thermal performance, 

total leakage, restraint requirements, overall 

work space design, and other bioengineering 

considerations.”130 Goodrich was designing a 

dome-type helmet to increase visibility and, 

hopefully, mobility.

By March 1960, NASA had ordered 

21 modified Mark IV suits for use on 

Project Mercury.131 NASA designated them 

XN-1 through XN-4 models, but engineers 

generally referred to them as “quick fix” 

suits. Spacesuits are well discussed in 

existing literature, so they will not be 

further covered here.
6
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

237

6: Air Force Full-Pressure Suits

Unlike the Navy, which began developing 

full-pressure suits almost immediately after 

World War II, the Army (and, subsequently, 

the Air Force after September 18, 1947) 

concentrated on further development of the 

partial-pressure suit. This was partly the result 

of the unhappy wartime full-pressure suit 

development effort and partly because the 

Henry Suit satisfied the immediate postwar 

need. The USAF appeared content to honor 

the 1947 agreement that assigned full-pressure 

suit development to the Navy, although it 

continued to monitor the progress being 

made in Akron, Philadelphia, and Worcester.

For example, the USAF Aero Medical 

Laboratory at Wright Field evaluated the Navy 

Model 1 full-pressure suit developed by the 

David Clark Company (DCC) in early 1949. 

The evaluators noted that the extreme fatigue 

experienced by the wearer while pressure 

breathing in USAF partial-pressure suits was 

absent in the full-pressure suit. The downside 

was that the full-pressure suit provided 

about 40 percent less overall mobility than 

the partial-pressure suit while inflated. 

Nevertheless, USAF evaluators believed the 

David Clark Company full-pressure suit was 

a marked improvement over the wartime 

MX-117 Goodrich suit.1

A 1955 survey by the Directorate of Research 

at the Wright Air Development Center 

showed the maximum altitude performance 

of U.S. military aircraft increased approximately 3 percent, compounded annually 

between 1918 and 1954. Although the 

curve at times dipped below the average, an 

abrupt increase always brought performance 

up to the curve at some later date. Surprisingly, the survey showed that steady progress 

was made despite economic depressions, 

wars, and the introduction of the jet engine. 

The directorate estimated that if progress 

remained constant, the operational ceiling 

for combat aircraft would increase to 

75,000 feet by 1960, 90,000 feet by 1965, 

and to a staggering 105,000 feet by 1970. 

Studies of advanced concepts that would lead 

to the development of the Republic XF-103 

and North American XB-70A Valkyrie seemed 

to confirm these predictions.2

The gradual, but relentless increase in altitude 

had become a problem during World War II, 

when aircraft reached altitudes above which 

man could not breathe without the benefit 

of pressurization. At roughly the same time, 

piston engines and propellers reached their 

effective altitude limits, although a few aircraft, particularly the Convair B-36, managed 

to defy the norm and operate at unthought-of 

altitudes. During the war, engineers developed 

workable jet and rocket engines that largely 

eliminated the altitude restrictions of piston 

engines. Re-engineering man, however, proved 

somewhat impractical. The first solution to 

breathing at high altitudes was to put the crew 

in a sealed cabin where oxygen, pressure, and 

temperature could be controlled to maintain 

a tolerable environment. The Boeing B-29 

Superfortress was the first combat aircraft 

equipped with pressurized cabins, but the 

Army soon realized the protection of a pressurized cabin could be suddenly nullified by 

mechanical failure or enemy action. Normally, 

B-29 crews were instructed to depressurize 

before going into combat. By the end of World 

War II, researchers and engineers had been 

wrestling with the problem for over a decade.3

The partial pressure Henry Suit provided an 

immediate, if not ideal, solution to sustaining 

humans at high altitude, but researchers kept 
The development of advanced weapons systems such 

as the North American XB-70A Valkyrie led many to 

believe the military would one day require thousands 

of pressure suits. As a bomber, the B-70 was supposed 

to be capable of Mach 3 speeds at altitudes greater than 

80,000 feet, performance the two prototypes eventually 

demonstrated on a limited basis. This is the second 

flight vehicle being rolled out in Palmdale, CA on 

May 29, 1965.

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

239

The Convair F-106 Delta Dart was the last in a long line 

of interceptors operated by the U.S. Air Force. The aircraft 

was supposed to be replaced by a Mach 3 interceptor, such as 

the North American F-108 Rapier, but this never happened. 

Eventually, modified tactical aircraft such as the McDonnell 

Douglas F-15 Eagle and Lockheed Martin F-16 Fighting 

Falcon found use as interceptors, but for the most part, the 

concept of a dedicated interceptor faded from the lexicon.

U.S. Air Force

looking for a better solution. The 

Featherweight B-36 bombers provided 

the impetus to put the MC-1 partial-pressure 

suit into production and the unanticipated 

demands of the U-2 resulted in the development of the improved MC-3 partial-pressure 

suit. At the same time, in early 1952 David 

Clark Company tailored one of its Navy 

full-pressure suits to fit Charles C. Lutz 

at the USAF Aero Medical Laboratory. 

Lutz conducted an extensive evaluation of 

the Model 14, finding that it was much 

better than the wartime suits but still not 

satisfactory for an operational garment.

The early 1950s was one of the times that 

aircraft performance took a major leap, 

much greater than the 3 percent average. The 

proposed operating altitudes of the Boeing 

B-52 Stratofortress, Convair B-58 Hustler, 

McDonnell F-101 Voodoo, and Convair 

F-102 Delta Dagger made the requirement 

for a new protective garment urgent. On 

May 15, 1953, the Air Research and 

Development Command directed the Aero 

Medical Laboratory to develop a high-altitude 

suit that would provide “protection against 

long-term exposure to altitudes in excess 

of 50,000 feet.”4

 The command stressed 

that, “since successful accomplishment of 

the mission and avoidance of enemy action 

make it necessary for the aircraft to remain 

at high altitude for considerably longer 

periods, a comfortable, wearable pressure 

suit is essential.”5

 Based on the anticipated 

schedule for the B-52, a prototype suit 

was required by June 1956 for engineering 

evaluation and full-scale service tests were 

to begin in June 1957. The Strategic Air 

Command, however, had a different schedule 

in mind and wanted the introduction of 

the new suit to coincide with the delivery 

of the first operational B-52s, advancing the 

in-service date to December 1955.

Likewise, the Air Defense Command (ADC) 

wanted the capability to intercept Soviet highaltitude bombers in the far north near the 

Arctic Circle. The selected countermeasure 

was to put an interceptor into a zoom climb 

at about a 60-degree angle of attack to get 

above 50,000 feet, lock onto a target, and fire 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

240

a nuclear-tipped missile. From the subsonic 

Northrop F-89 Scorpion and Lockheed 

F-94 Starfire, the ADC began transitioning 

to the supersonic F-101 and F-102, then to 

the Mach 2 Lockheed F-104 Starfighter and 

Convair F-106 Delta Dart. The command 

was also looking forward to the introduction 

of a Mach 3 interceptor, such as the Republic 

F-103 (cancelled August 21, 1957), North 

American F-108 Rapier (cancelled on 

September 23, 1959), or Lockheed YF-12A 

(only three built). In addition to increasingly 

high speeds, these aircraft were also flying 

higher, with the F-106 capable of operating 

at 57,000 feet, and the F-108 and YF-12 

expected to exceed 80,000 feet. According to 

Air Force regulation, to fly above 50,000 feet 

required the use of a pressure suit.6

Although the MC-3 and MC-4 partialpressure suits used by the ADC provided 

adequate get-me-down protection for crews 

of earlier aircraft, they were not “mission 

completion” suits and were unsuitable for 

the expected Mach 3 interceptors. The 

ideal pressure suit would protect against the 

adverse effects of a high-altitude emergency 

(loss of cabin pressure) and provide adequate 

comfort and mobility to complete the 

assigned mission. In addition, the suit needed 

to provide protection from exposure in an 

extremely cold (Alaska or Canada) land or 

water environment in the event the pilot had 

to eject from his aircraft.7

Researchers at the Aero Medical Laboratory 

concluded that a full-pressure suit would best 

meet these requirements. However, the prospect of developing a full-pressure suit placed 

the USAF in a somewhat uncomfortable position in regard to its 1947 agreement with the 

Navy. Seeking a solution, representatives from 

the Aero Medical Laboratory and Bureau of 

Aeronautics met in January 1954 to discuss the 

new requirements. The Navy agreed to accelerate its full-pressure suit program with a goal 

of delivering an experimental suit to Wright 

Field in June 1954 at a cost of $244,000. The 

Aero Medical Laboratory was skeptical of this 

schedule, doubting that sufficient development 

work could be completed in the intervening 

4 months. Nevertheless, Air Force Headquarters transferred funds for five suits, “to be 

delivered not later than June 1, 1954.”8

Since 1946, the Navy had conducted a small 

but active full-pressure suit development 

program. Although the original contract with 

the David Clark Company was running out 

of funds, a new contract with B.F. Goodrich 

was showing promise. However, the Navy’s 

needs were substantially different from those 

of the forthcoming B-52. For the most part, 

the Navy operated short-range fighters, and 

its needs for an altitude suit could probably 

be met by the T-1 partial-pressure suit as a 

get-me-down garment. On the other hand, 

the USAF was faced with a requirement for 

an altitude suit that allowed unprecedented 

long-term comfort and mobility while providing adequate physiological protection for 

long-range strategic bombing, reconnaissance, and refueling missions. The Air Force 

also worried about relying on B.F. Goodrich, 

which had been one of the contractors for 

the full-pressure suit the Army had cancelled 

in 1943. There was apprehension within the 

USAF that the new Navy suit might look 

very much like the unsatisfactory garment the 

Army had discarded 10 years earlier.9

Another factor in the USAF’s skepticism 

was the division of responsibility between 

the Bureau of Aeronautics (BuAer) and the 

Bureau of Medicine (BuMed). Unlike the 

Aero Medical Laboratory, a physiological 

research organization that could generally procure whatever services and products it needed 

to support its development programs, BuMed, 

the developer, was dependent upon BuAer for 

all procurement activities. Nevertheless, the 

Navy program appeared to be moving ahead 

without undue difficulty.

In April 1954, the Aero Medical Laboratory 

evaluated an early Navy-Goodrich Model H 

full-pressure suit in the XB-58 cockpit 

mockup at the Convair plant in Fort Worth, 

TX. The Air Force evaluators thought the 

suit was uncomfortable, lacked mobility, had 

restricted vision, inadequate ventilation, poor 

land-survival qualities, and was difficult to 

don and doff. Interestingly, these were almost 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

241

the opposite of the conclusions drawn by 

the Navy. By September 1954, the USAF 

concluded that the Navy effort would not 

produce an acceptable suit that could meet 

the in-service date of the B-52.

The Franklin Institute in Philadelphia hosted 

the Omni-Environment Full-pressure Suit 

Symposium, which was co-sponsored by the 

Air Force and Navy on February 1–3, 1955. 

During the meeting, several David Clark 

and Goodrich pressure suits were presented, 

often under pressure, for the audience. Also 

during the course of the symposium, the 

Aero Medical Laboratory announced it was 

proceeding with an independent full-pressure 

suit development effort to satisfy USAF 

requirements. The Navy offered no objections, 

at least not in public.10

LINES OF NONEXTENSION

Independently of the Navy and USAF efforts, 

beginning in 1947, the National Bureau of 

Standards funded research by Dr. Arthur S. 

Iberall that ultimately defined a principle 

called Lines of Nonextension. If you look at 

the human body as it moves, there are areas 

where the skin stretches with the movement 

of joints and other areas where it does not. 

The latter are the lines of nonextension. This 

told designers what parts of a pressure suit 

needed to be flexible and what areas could 

remain rigid. Iberall found that 

Since the human body tends to retain 

its form, taking no appreciable ‘set’ 

after ordinary body deformations, its 

behavior is expected to conform to the 

laws of physical elasticity. Deformations 

in an elastic body are described by the 

strain ellipsoid, in which a small sphere 

of material deforms to nearly ellipsoidal 

shape under elastic deformation of the 

entire body. On the surface of such an 

elastic body, the projected deformations 

transform a small circle into an ellipse. 

Since all points on the ellipse are derived 

from points on the undeformed circle, in 

general, there may be two diameters in 

the ellipse that are not stretched. (They 

may be noted by superimposing the original circle on the deformed ellipse.) An 

extension and connection of these radial 

directions may be referred to as a mapping of the surface of the elastic body by 

‘lines of nonextension.’ Such a theory is 

expected to be applicable to the surface 

of the human body. If so, high strength 

strands of material may be laid along 

these directions and joined at their interstices for free-rotation capability. These 

strands can then carry loads developed by 

the pressure forces transmitted against the 

strands, without interfering with mobile 

deformations of the body.11

Armed with an ink marker, Iberall spent a 

considerable amount of time mapping the 

lines of nonextension on several subjects in 

leotards. Ultimately, the National Bureau of 

Standards funded two prototype pressure suits 

based on this principle. The second prototype, 

completed in 1951, was a fascinating combination of metal frames, rubber bladders, and 

net-covered joints pressurized to 2 psi.12 The 

netted joints were one of the more interesting 

aspects of this suit since they were an early 

attempt to provide better mobility than the 

various mechanical and rubber joints used in 

the past. Iberall explained 

Having established the lines of nonextension and having transferred them to an 

anthropological sizing manikin, patterns 

were cut in accordance with these lines—

first with a coarse decorative fish-net for 

practice, and then with a Dacron net 

with about four diamonds to the inch. 

This net was procured from a local knitter, one of a considerable number of 

suppliers who can knit net. The major 

requirements are that high-strength 

yarn be used (the thread used is twoply, 1,100-denier yarn), that a sufficient 

amount of Dacron be packed into the 

strand (5,000 denier or more), and that a 

very tight knitting be used. It is desirable 

that the strand strength be 50 pounds 

per strand or higher.13

In 1954, Iberall moved to the RAND 

Development Corporation where he 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

242

continued working on pressure suits. Iberall 

claims that his netted joints were the basis 

for all suits that followed, but it is not 

clear this is the case. In his memoirs, and 

supporting documentation seems to back up 

the remembrances, David Clark attributes his 

company’s Link-Net to an idea he had while 

traveling back from visiting his daughter in 

Alaska. On the way home, Clark used a string 

to mock up a collar section of a pressure-suit 

restraining garment. When he got back to 

Worcester, seamstress Rose Arlauskas helped 

Clark refine the sliding mesh-restraint concept 

that eventually became Link-Net. There is 

little doubt that Clark and Iberall knew each 

other, and correspondence indicates that 

Clark may have assisted Iberall obtaining 

employment with RAND. However, David 

Clark was, among other things, a generous 

person when it came to giving credit where it 

was due; his memoirs are filled with references 

to other people’s good work. So, it is notable 

that Iberall is not credited with regard to 

Link-Net.14

Nevertheless, Iberall’s research came to some 

interesting conclusions that were undoubtedly 

of benefit to the industry. For instance, he 

conducted research into how human subjects 

perceived various fabrics and materials. 

Latex rubber, a common material used in 

the manufacture of early pressure suit gas 

containers proved to be a favorite subject. 

Iberall found, “a thickness of 0.002-inch is 

almost unnoticeable to the wearer, 0.005-inch 

is quite comfortable, 0.010-inch acceptable, 

0.015-inch tolerable, and 0.025-inch is 

uncomfortable.”15 It provided a useful basis 

for others to fabricate gas containers.

While at RAND, in 1958, Iberall fabricated 

another prototype full-pressure suit. The 

restraint layer used Iberall’s version of a slipnet material made of woven Dacron fiber. 

He laid the material on a sizing mannequin 

so that the direction of slip conformed to the 

lines of nonextension that he had previously 

drawn on it. Iberall pointed out that the material did not need to perfectly conform, but 

“only a reasonable approximation to the lines 

is necessary to permit ample mobility.”16 A 

second restraint layer consisted of a cloth-like 

covering over the chest and rigid coverings 

over the pelvis, thighs, legs, arms, and head, 

with slip-net lacing between the trousers and 

vest sections, trousers and thigh sections, and 

chest and upper arm sections. This layer was 

worn over the slip-net restraint layer.

Iberall created his 0.012-inch-thick latex gas 

container by dipping a full-size mannequin 

into a vat of liquid latex rubber under environmental conditions that ensured the desired 

thickness would cure after the mannequin 

was removed from the vat. Iberall fabricated 

the gas container in four sections: an upper 

and lower torso and the two arms. After the 

gas container cooled, a thin leotard was glued 

to the outside to provide support. Iberall 

designed the two halves of the torso to be 

sealed by folding at the waist, much like the 

contemporary David Clark MC-2 suit.

Iberall used a commercially available fibrous 

spacer material to construct a ventilation layer, 

also based on the lines of nonextension. This 

layer was worn outside a set of long underwear, with the gas container and two restraint 

layers over it. A fiberglass helmet was fastened 

to the slip-net restraint layer, and two steel 

bands held the helmet to the outer restraint 

layer to prevent rising. A pair of commercial 

high-laced work shoes purchased at an ArmyNavy surplus store and thin kid-leather dress 

gloves completed the ensemble. The suit was 

pressurized using a connection on the chest, 

and air exhausted through connections on the 

shins and forearms.

Iberall sized the tight-fitting suit for three 

RAND employees who were used as test subjects. When the suit was taken to the Aero 

Medical Laboratory at Wright Field, Charles 

Lutz decided to test the garment, as he had 

done with nearly all other pressure suits evaluated by the USAF. Although Lutz was somewhat taller than the RAND personnel, the suit 

fit reasonably well. Lutz reported: 

When I am completely dressed, the suit 

impairs my breathing because of its tightness. Some relief can be obtained by 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

243

bending over and raising the shoulders 

and arms. Other areas of discomfort 

were under the arms and over the shoulder blades. Even though suit donning 

required about 2 hours, I remained comfortable, temperature-wise, though no 

vent air was passing through the suit. Pressurizing to about 1/4-psi expands the garment, correcting the breathing difficulty 

but not the tightness under the arms. At 

1 psi, the tightness under the arms was 

gone, and the suit was very comfortable 

at all higher pressures, including the 

highest elected pressure, 4 psi.... Though 

the garment provides comparative ease 

of movement and the ability to hold the 

assumed position, when one relaxes, the 

suit returns to a neutral position. Also, 

the elbows cannot be held tightly against 

the sides of the suit torso.17

The Iberall suit was an interesting experiment 

but was in no way a prototype of an operational garment. For instance, the thin 

gas container was prone to punctures, and 

even Iberall recognized that “significantly 

better solutions will take serious research.”18

The suit offered decent mobility while pressurized to 3.0 psi but was not significantly 

better than the suits being developed at 

David Clark Company or Goodrich. Iberall 

concluded, “Having completed the theory of 

operation, and fully demonstrated its experimental feasibility, there remains the task of 

engineering research and development of most 

suitable materials, and a structural integration 

of layers into a possible operational suit.”19

Iberall continued his suit activities at RAND 

for at least 10 years. Several references, all 

written many years later, say his 1958 suit 

competed with the XMC2-DC and XMC2-

ILC for the X-15 program, but there is no 

contemporary documentation that seems 

to support this speculation. In any case, the 

RAND-Iberall suit was not, directly at least, 

chosen for any specific work. Nevertheless, 

the lines-of-nonextension theory proved 

useful for other suit designers.

MC-2—A NEW BEGINNING 

The requirements for the new USAF suit 

announced at the 1955 Omni-Environmental 

Full-pressure Suit Symposium included providing a minimum of 12 hours protection 

above 55,000 feet in temperatures ranging 

from −40 oF to the highest cockpit temperature envisioned for aircraft flying at a true 

airspeed of 1,200 knots. In addition, the suit 

needed to provide the same protection as the 

standard USAF G-suit. The “fully mobile suit” 

needed to weigh less than 30 pounds, operate 

at an internal pressure of 5 psi, and provide 

the wearer with sufficient oxygen partial pressure, adequate counter-pressure, and suitable 

ventilation.20 Looking forward, by 1965, the 

Aero Medical Laboratory expected to need 

pressure suits that provided protection for 

9 hours at 1,600 knots and 86,000 feet 

and, almost unbelievably, for 7 hours at 

2,200 knots and 100,000 feet by 1970.21

The Aero Medical Laboratory asked 

30 companies to bid on a competitive design 

study for this full-pressure suit. From this 

group, the laboratory intended to select six 

to eight firms to conduct preliminary studies 

that would become the basis for a composite 

suit design incorporating the best engineering 

features from each study. After the design was 

completed, interested manufacturers would 

bid on a production contract.22 This was subtly 

different from the Navy method. The USAF 

expected a single company to develop the 

suit, and then the service would compete suit 

production as a “build-to-print” effort where 

the winner(s) fabricated identical suits. This 

was how G-suits and partial-pressure suits were 

procured. The Navy, on the other hand, issued 

a functional specification and each fabricator 

developed its own design that met the 

requirements, resulting in multiple garment 

designs that were functionally identical.

The Air Force received bids from 10 companies

before the May 16, 1955, closing date, but 

only four of these covered complete suit systems; five were for component development, 

and one represented a human engineering 

evaluation. Funding and schedule concerns 

forced the laboratory to change its course, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

244

and instead of study contracts, the USAF 

awarded development contracts to the David 

Clark Company and International Latex 

Corporation (ILC). Both of the resulting fullpressure suits were designated XMC-2, and to 

differentiate between the two suits, the initials 

of the companies became part of the designation. Therefore, the David Clark Company 

suit became the XMC-2-DC (the Air Force 

only used the first two letters for David Clark, 

perhaps because of its familiarity with the 

man, was well as with the company), and the 

ILC suit became the XMC-2-ILC.23

Despite the needs of the B-52 and other 

advanced operational aircraft, ultimately three 

small, black, rocket-powered research airplanes 

would drive the development and configuration of the first USAF full-pressure suit. Air 

Force partial-pressure suits and Navy fullpressure suits had performed well in the 

so-called Round One X-planes—the Bell X-1 

and X-2, and the Douglas D558 series. In 

1954, the Air Force, Navy, and the NACA 

agreed that the Round Two X-plane would 

provide a significant increment in performance. The military would fund the program, 

with the Air Force taking the lead for the 

airframe and engine and the Navy providing 

physiological research and training using the 

human centrifuge at NADC Johnsville.24

Once the basic flight envelope had been 

opened, the NACA would use the airplanes 

to explore hypersonic (in excess of Mach 5) 

heating, aerodynamics, and stability and 

control at altitudes up to 250,000 feet. In 

November 1955, the Air Force selected North 

American Aviation to build the X-15 airframe 

and subsequently selected Reaction Motors, 

Inc. to develop the XLR99 rocket engine. 

Perhaps most significantly, already legendary 

test pilot Scott Crossfield left the NACA to 

join North American so he could be more 

involved in the development of the airplane. 

The X-15 would become, arguably, the most 

successful, and certainly the fastest and highest 

flying, of the X-planes.

At the beginning of the X-15 program, there 

had been scant success in creating a workable full-pressure suit. The Army’s wartime 

MX-117 experience was almost entirely 

unhappy, although the Navy was beginning 

to make some progress with the David Clark 

and Goodrich designs. This led to a certain 

amount of indecision regarding the type of 

garment needed for the X-15. At the insistence 

of Crossfield, North American proposed a fullpressure suit to protect the pilot during normal operations and emergency escape. It was a 

controversial decision.

Despite the early state of development of 

full-pressure suits, Crossfield was convinced 

one was necessary for the X-15, so on April 8, 

1956, North American issued a specification to the David Clark Company for the 

development, fabrication, and testing of a fullpressure suit. Crossfield had great confidence 

in David Clark, both the company and the 

man.25 As a test pilot, Crossfield used an early 

David Clark Company suit developed for 

the Navy when he became the first person to 

exceed Mach 2 in the D558-2. As an engineer, 

Crossfield needed to know everything about 

how the suit worked, and he spent a lot of 

time in Worcester.

Less than a month later, however, on advice 

from the Aero Medical Laboratory, the X-15 

Project Office advised North American to 

use a partial-pressure suit in the X-15. It 

was the beginning of a heated debate. North 

American—and particularly Scott Crossfield—

refused to yield, and during a meeting in 

Inglewood on June 20–22, 1956, the USAF 

began to concede. Crossfield demonstrated 

the David Clark Model 12 full-pressure 

suit, the same suit he wore on his Mach 2 

D558-2 flight, during the preliminary X-15 

cockpit mockup inspection. Although the 

suit was far from perfect, it convinced the 

Aero Medical Laboratory that, “... the stateof-the-art of full-pressure suits should permit 

the development of such a suit satisfactory for 

use in the X-15.”26 There were other reasons 

that Crossfield, and several NACA researchers, 

wanted a full-pressure suit. The USAF had 

decided that all future aircraft, including the 

X-15, would use an escape capsule of some 

description. Crossfield, familiar with the 
245

The International Latex Corporation XMC-2-ILC suit was 

not truly a prototype of an operational suit but more of a 

conceptual demonstrator. Perhaps its most unusual feature 

was the lack of gloves or mittens. The suit, however, did 

contain an innovative helmet holddown system that would 

soon be adopted by other manufacturers. This suit never stood 

a chance against the David Clark Company offering, but 

laid the groundwork for what became the Apollo spacesuits.

National Museum of the U.S. Air Force Collection

concept from the Bell X-2 and Douglas D558 

series, was not a believer. Escape capsules 

were heavy and would adversely affect the 

performance of the new hypersonic research 

airplane. They also appeared to hamper, rather 

than enhance, a pilot’s ability to escape from 

a stricken aircraft. Crossfield thought the best 

answer was a sophisticated ejection seat to get a 

pilot out of the airplane and a full-pressure suit 

to protect him. 

During a meeting on July 12, 1956, representatives from the USAF, Navy, and North 

American reviewed the status of full-pressure 

suit development and the Aero Medical 

Laboratory committed to procuring such a 

suit for the X-15. Although the X-15 

contract gave this responsibility to North 

American, Crossfield agreed that the Aero 

Medical Laboratory should provide the 

suit. Crossfield could not legally change the 

suit from a contractor-furnished item to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

246

Government-furnished equipment, but 

he agreed to recommend that North 

American accept such a change. There was 

little doubt the company would agree. 

Crossfield insisted, however, that the laboratory design the garment specifically for the 

X-15 and make every effort to provide an 

operational suit by late 1957, to support the 

first flight. The X-15 Project Office accepted 

responsibility to fund the suit-development 

program. Although the July 12 agreement 

effectively settled the issue, the paperwork 

to make it official moved somewhat slower; 

the USAF did not change the suit from contractor-furnished to Government-furnished 

until February 8, 1957.27

In the meantime, the Aero Medical Laboratory 

encouraged David Clark Company and ILC to 

orient their prototype suits toward the anticipated needs of the X-15, although the suits still 

needed to satisfy the advanced-weapons-system 

requirements originally imposed.28

The XMC-2-ILC proved to be an unwieldy 

garment that used convoluted “tomato worm” 

joints at the shoulders, elbows, and waist. Similar convolutes covered the legs from the thighs 

to the ankles, with no separate knee joint per 

se. The ILC convolutes were much finer than 

those used by Goodrich during the wartime 

MX-117 program, mostly to minimize the 

exertion needed to manipulate them. ILC 

used metal bearing rings under the shoulder 

convolutes to provide additional mobility. A 

set of laces ran horizontally around the chest to 

allow the torso height to be adjusted. Donning 

occurred through a horizontal zipper around 

the hips, and the pressurization air inlet was in 

the center of the chest.29

Interestingly, the XMC2 contract did not 

specifically state that the bidder had to supply 

gloves, so the ILC suit had large bags at the 

ends of the arms with no finger or thumb 

separations. The head was covered by a 

rubberized, close-fitting cap and a standard 

Air Force partial-pressure helmet and pressurebreathing mask. An innovative feature 

that would find future use was the helmet 

holddown system. A steel cable fastened to 

the bottom sides of the helmet and ran 

through a pulley under the chin to the crotch. 

The pilot could adjust the length of the cable 

to keep the helmet from rising and also to 

stand or sit as needed.30

Unfortunately, the joint bearings produced 

painful pressure points on the body, and the 

Aero Medical Laboratory thought they would 

present a hazard during bailout or ejection. 

The suit ballooned unacceptably under pressure and was extremely stiff and difficult to 

move in. ILC had started the competition 

at a disadvantage since it had no previous 

pressure-suit experience, whereas David Clark 

Company had been developing partial- and 

full-pressure suits for most of a decade. 

Although the Air Force did not select the ILC 

suit for further development, the experience 

laid the groundwork for what became the ILC 

Apollo spacesuits a decade later.31

In contrast, the David Clark Company built 

on the experience gained during its Navy 

full-pressure suit effort. The first task was to 

evaluate various materials, particularly an airtight fabric with a minimum of bulk that was 

capable of joint mobility under pressure. Several unsupported sheet-rubber materials were 

evaluated but all were ultimately discarded 

since they collapsed when punctured. Efforts 

then turned to neoprene-coated nylon materials for which a puncture resulted in a small 

leak but not a sudden expulsion of gas. The 

restraint fabric was easier to select: a nylon 

marquisette with a tensile strength of 64 psi 

on the fill and 130 psi on the warp.32

Joseph A. Ruseckas and John E. Flagg at 

David Clark Company constructed three 

torso mockups using neoprene-coated nylon 

and two layers of nylon marquisette on 

opposite biases. They reinforced the crotch 

section with an extra layer of marquisette 

and made the gas container approximately 

10 percent larger than the restraint garment. 

The first mockup survived 510 cycles 

from 0.5 psi to 5.0 psi without failure. 

The second torso was used for overpressure 

tests, surviving 10 psi without incident (a 

2-times factor of safety), ultimately failing at 
237

The lower torso of the MC-2 shows the Link-Net restraint 

over the lower pressure trousers. The subject has not yet 

donned the upper torso pressure bladder and upper torsorestraint layer. This gives a good image of the rubber flap at 

the top of the trouser bladder that was folded together with 

the upper torso bladder to form a waist seal. The upper 

Link-Net torso-restraint zipped to the lower torso-restraint 

at the waist. Note the anti-G suit hose on the left side.

National Archives College Park Collection

11.5 psi. Redesigning the crotch allowed this 

torso to survive 15 psi. The third torso was 

submitted to 65 inflation cycles from 0.5 psi 

to 8.0 psi with no fabric or seam failures. At 

8 psi, the torso increased about 7 percent in 

circumference, but it showed no significant 

increase in length.

David Clark Company fabricated a fourth 

mockup using nylon-cotton basket weave for 

the restraint garment but using nylon LinkNet for the shoulders and sleeves. This was 

a two-piece garment the pilot entered at the 

waist. The gas container featured rollup seals 

16 inches long, one attached to the top section and one to the bottom. The ends of the 

seals were rolled together to form a gastight 

seal. At least that was the theory. In reality, the 

lap seam used to attach the seals to the rest of 

the gas container leaked, causing David Clark 

Company to develop a dipping process that 

eliminated the seams and the leakage.
236

The David Clark Company XMC-2-DC was considerably 

more advanced than the ILC suit and was the first use of 

Link-Net on a full-pressure suit. It is impossible to ascertain 

details of the suit under the aluminized exterior cover. The 

Aero Medical laboratory tested the suit during 1957 in the 

Wright Field altitude chamber. The Air Force considered 

the David Clark suit vastly superior to the ILC garment, 

but there were still several significant shortcomings. 

National Archives College Park Collection

The restraint layer featured a major breakthrough with the use of a new “distorted-angle 

fabric” called Link-Net, which was used to 

control ballooning and enhance range of 

motion. This eliminated the need for the 

tomato-worm bellows at the limb joints used 

by ILC and most of the World War II suits. 

Link-Net is a series of parallel cords that loop 

each other at frequent intervals. The loops 

are interlocked but not connected so that 

the cords can slide over each other and feed 

from one section of the suit to another. This 

allowed the suit to deform easily.33 Ed Dubois, 

the softgoods expert at David Clark Company, 

emphasized the fabric was very comfortable when unpressurized because it collapsed 

instead of bunching up as the wearer moved.34

The main characteristic required of Link-Net 

was the lowest possible resistance to bending 

and twisting, but the elasticity had to be mini-

mal since the restraint layer could not allow 

the suit to increase appreciably in size under 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

249

Dr. Edwin G. Vail of the 

Aero Medical Laboratory 

evaluated the XMC-2-

DC on the Wright Field 

centrifuge during late 1957. 

These tests included runs 

at 7-G to demonstrate the 

built-in G-suit. This was 

well below the maximum 

capability of the machine 

(22-G) but was more than 

expected from the new X-15 

research airplane. 

National Archives College 

Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

250

pressure. The use of a relatively nonelastic cord 

in the Link-Net made it possible to satisfy 

these seemingly contradictory requirements. 

David Clark selected nylon for Link-Net 

because of its high tensile strength, low weight, 

and low bulk ratio. The cord and stitch sizes 

were determined from torsion tests performed 

on untapered cylindrical sleeves. Researchers 

rotated one end of the sleeve relative to the 

other end and recorded the retarding torque 

as a function of the angular displacement. The 

tests revealed the best combination of cord and 

stitch size to give the least retarding torque. 

For instance, for a given cord size, a larger 

stitch size was best until the stitches became 

so large that the gas container forced its way 

between them. David Clark Company decided 

to limit the stitch size to 0.3125-inch, and 

smaller diameter cord provided the net with 

greater flexibility. Eventually the designers 

settled on a 36-pound test cord that provided 

a safety factor greater than 10.35

The enormous advantages offered by the LinkNet fabric were initially hard to fully grasp. 

The fabric allowed David Clark Company to 

design a suit that provided reasonable mobility 

without resorting to complicated mechanical 

or metal joints, saving considerable weight and 

providing much better comfort. Coupled with 

advances in regulators and other mechanical 

pieces, David Clark Company produced 

a workable full-pressure suit that weighed 

about 35 pounds. Previously, during the early 

X-15 proposal effort, North American had 

estimated a suit would weigh 110 pounds.36

Developing the XMC-2-DC (DCC model 

S794) suit provided a tremendous learning 

experience for the company. The suit included 

lower-leg and ankle sections made of nylon 

marquisette, a side-opening zipper, and a strap 

that slipped under each foot to keep the torso 

section from elongating under pressure. The 

initial anti-G bladders were fabricated using 

neoprene-coated nylon, but they failed during 

testing. New bladders incorporated a nylonoxford restraint cover, and these passed the 

pressure tests. David Clark Company included 

an automatic bleed feature in the G-suit outlet; if the pilot ejected while the G-suit was 

inflated, the bleed automatically relieved the 

counter-pressure during descent. Once the 

G-suit bladders were completely empty, the 

bleed closed to seal out water.37

For the gloves, David Clark Company 

evaluated leather/nylon, leather/nylon/

Link-Net, and all leather. Eventually, the 

company determined the best combination 

“Jack” McKay showing the restraint layer of an MC-2 suit 

on April 15, 1959. Note the gloves are permanently attached 

to the restraint layer. The MC-2 was the first suit made by 

David Clark Company where the entire restraint layer was 

fabricated from the breakthrough Link-Net.

NASA
237

The new “distorted-angle fabric,” development by David 

Clark Company, Link-Net, was one of the breakthroughs 

that allowed the company to fabricate a workable fullpressure suit that offered reasonable mobility.

Courtesy of the David Clark Company, Inc.
It’s a posed publicity shot, and the MC-2 is not representative 

of production suits, but the photographer managed to 

catch the mystic surrounding full-pressure suits during the 

1950s. There is no record of the silver boot covers being used 

operationally. This is the Wright Field thermal chamber 

during 1957 or 1958.

National Archives College Park Collection

was leather covering the hand with a stainless 

steel palm restrainer stitched inside nylon 

tape that was supported by nylon tape 

around the back. The glove used Link-Net 

from the wrist to the top zipper and a black 

cabretta top seam. However, test subjects 

quickly found that gloves constructed in the 

straight hand position made it impossible to 

hold an object—such as a control stick—for 

more than 15–20 minutes while the glove 

was pressurized. When the company used a 

natural semiclosed position for the glove, the 

subjects could hold an object up to 2 hours 

without undue discomfort. Perhaps the most 

surprising material used in the prototype suit 

was for the boots: kangaroo leather, which 

ended up being soft and comfortable but 

sufficiently durable.38

During the Aero Medical Laboratory 

evaluation, the David Clark Company suit 

was clearly superior to the ILC prototype. 

Although there was obvious room for 

improvement, there was little doubt that 

David Clark Company was much closer to 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

253

Each of the early MC-2 suits was subtly different as researchers worked through various problems. It is not certain which 

of the preproduction MC-2 suits these are, but they differ in 

numerous details. For instance, the suit on the left has a twopulley helmet-holddown system and the forearms and gloves 

differ significantly.

Courtesy of the David Clark Company, Inc.

developing a satisfactory full-pressure suit 

than ILC, and the Air Force declared the 

company the winner. Subsequently, the Aero 

Medical Laboratory, using funds provided 

by the X-15 Project Office, awarded David 

Clark Company a contract to develop the 

definitive X-15 full-pressure suit, although the 

suit also needed to meet the existing weaponssystems requirements.

The construction of two “production” MC-2 

suits (S794-1 and S794-2) followed. The 

suits consisted of heavy wool underwear, 

an integrated G-suit, a gas container, upper 

and lower restraint layers, an exterior cover, 

a parachute harness, gloves, boots, and a 

helmet. The exterior cover was made from 

aluminized green nylon and made the MC-2 

look every bit the spacesuit that the popular 

press made it out to be. The two suits were 

similar except the first had the pressure vent 

fitting located at the back, near the shoulder 

blades, and the second located it on the left 

thigh. In addition, the gloves on the first 

suit were removable, using a rollup seal like 

the waist, while the gloves were permanently 

attached to the second suit.39

One of the major changes in these suits 

was extending the use of Link-Net material 

further from the joints to increase the amount 

of “draw” and provide additional mobility. 

Eventually the David Clark Company 

designers concluded that the entire restraint 

layer should use Link-Net. David Clark 

delivered these two suits to the Aero Medical 

Laboratory at Wright Field for evaluation and 

used the lessons learned to construct the first 

X-15 suit for Scott Crossfield.

The third suit (S794-3C) incorporated 

several changes requested by the Aero 

Medical Laboratory after a brief evaluation 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

254

Table 4—Pressure Time Log for the S794-3C Suit

Date Time Location Notes

Sep 18, 1957 3 hours David Clark Company

Sep 19, 1957 2 hours, 50 minutes David Clark Company

Sep 22, 1957 2 hours, 20 minutes David Clark Company

Sep 23, 1957 3 hours, 10 minutes David Clark Company

Sep 28, 1957 5 hours Firewel Company Altitude Chamber

Sep 29, 1957 4 hours Firewel Company Altitude Chamber

Sep 30, 1957 2 hours, 15 minutes David Clark Company

Oct 7, 1957 3 hours, 30 minutes North American Aviation

Oct 8, 1957 5 hours, 35 minutes North American Aviation

Oct 9, 1957 2 hours North American Aviation Altitude Chamber

Oct 10, 1957 3 hours, 25 minutes North American Aviation

Oct 11, 1957 2 hours, 15 minutes North American Aviation

Oct 14, 1957 1 hour, 20 minutes Wright Field Centrifuge

Oct 15, 1957 1 hour, 40 minutes Wright Field Centrifuge

Oct 16, 1957 1 hour, 15 minutes Wright Field Hot Box

Oct 16, 1957 1 hour, 45 minutes Wright Field Hot Box

Oct 17, 1957 2 hours, 10 minutes Wright Field Centrifuge

Oct 17, 1957 1 hour, 30 minutes Wright Field Altitude Chamber

Oct 22, 1957 3 hours David Clark Company

Oct 24, 1957 1 hour, 40 minutes David Clark Company

Oct 27, 1957 2 hours, 15 minutes David Clark Company

Nov 13, 1957 2 hours Wright Field

Nov 15, 1957 1 hour, 45 minutes Wright Field

Nov 21, 1957 45 minutes David Clark Company

Nov 26, 1957 6 hours, 15 minutes David Clark Company

Total Time 66 hours, 40 minutes

Source: “Development of a Full-pressure Suit System,” David Clark Company, ASD Technical Report 61-116, May 1961.
237

Another posed photo showing Scott Crossfield at NADC 

Johnsville in front of the human centrifuge. The neck seal is 

evident in this photo, as is the parachute harness integrated 

into the outer cover garment.

National Archives College Park Collection

of the first two “production” S794 garments. 

The complete suit, with helmet, weighed just 

shy of 37 pounds. Of this, the back pan, regulator, and emergency oxygen supply weighed 

13.5 pounds, the helmet 5 pounds, the boots 

3 pounds, and the underwear and socks 

3 pounds. The pressure suit itself, including 

the gas container, G-suit, restraint layer, exterior cover, and gloves weighed 12.5 pounds.

David Clark shipped the third suit to 

Inglewood for evaluation in the X-15 cockpit 

mockup for 6 days beginning October 7, 

1957. While at North American, the suit 

underwent pressure checks, X-15 cockpit 

compatibility evaluations, ventilation checks, 

and altitude chamber runs. Unfortunately, 

the North American altitude chamber effort 

proved pointless since the chamber only went 

to 40,000 feet and the suit controller had 

been set to pressurize above 40,000 feet.40

Crossfield then took the S794-3C to the 

Aero Medical Laboratory for evaluation. 

On October 14, he demonstrated the suit 

in the Wright Field centrifuge during two 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

One of the qualification tests required before pilots could 257

use the MC-2 in the X-15 was rocket-sled evaluations up 

the maximum dynamic pressure predicted during an 

X-15 ejection. Surprisingly, this test is not as extreme as one 

would first imagine, simply because the X-15’s maximum 

speed was at high-altitude (over 80,000 feet) where air 

pressure is negligible. In this May 1958 test, an anthropomorphic dummy is strapped into a boilerplate version of the 

X-15 ejection seat on the rocket sled at Edwards AFB, CA. 

U.S. Air Force

of the T-33. Tests in the F-104B proved more 

comfortable, primarily because high-pressure 

air was available for suit ventilation but also 

because the cockpit was somewhat larger. The 

pilots suggested various improvements after 

these flights, many concerning the helmet and 

gloves, but overall the comments were favorable. The suit accumulated 8.25 hours of flight 

time during the tests.43

David Clark Company designers took these 

comments and rebuilt the S794-4 suit. The 

revised suit used a two-piece Link-Net neck 

to minimize helmet rise and increase mobility. 

Tests showed that the changes seemed to help, 

but the helmet still rose, possibly because the 

torso was stretching. The new neck increased 

head mobility, and the helmet could be moved 

forward, until the neck ring touched the 

chest, and slightly aft and sideways. The same 

neck construction was used on the S794-5 

suit. The shoulder was redesigned, mostly by 

abbreviating the shoulder ring to an underarm 

contour, eliminating the outboard tape at the 

shoulder, and extending the contour to the 

neck tape at the top of the shoulder. David 

Clark Company also reworked the knees 

using a two-way stretch material and installed 

a compensated G-bladder dump valve. The 

revised suit was delivered to Wight Field on 

July 17, 1958.

On April 10, 1958, the Aero Medical 

Laboratory advised the X-15 Project Office 

that David Clark Company planned to 

deliver the first flight-qualified suit (S794-6) 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

258

for Scott Crossfield on June 1, 1958. The 

laboratory cautioned, however, that the 

X-15 program would only receive four suits 

under the current contract. The laboratory 

planned to order other MC-2 suits for service 

testing in operational aircraft, but these 

were not compatible with the X-15 cockpit 

because the X-15 ejection seat used a back 

kit instead of a seat kit. As the name implies, 

this is the location of the emergency oxygen 

and other equipment needed to support a 

pressure suit. If additional suits were required, 

the X-15 Project Office would need to 

provide the Aero Medical Laboratory with 

additional funds.44

Given a lack of funds for further suits, the 

X-15 Project Office investigated the feasibility 

of using a seat kit instead of the back kit used 

on the first four suits. This would allow the 

use of suits designed for service testing and 

would permit X-15 pilots to use the suits in 

operational aircraft. The benefits of using a 

common suit would have been substantial, but 

by May 1958, it was too late, since the X-15 

design was too far along to change. Although 

the X-15 Project Office continued to evaluate 

the idea, the X-15 suit remained different than 

similar suits intended for operational aircraft. 

The X-15 Project Office subsequently found 

funds for two additional suits.45

Since the USAF intended the use the MC-2 

in aircraft other than the X-15, David Clark 

Company fabricated a suit (S794-7) that 

used a seat kit instead of the back kit used 

for the X-15. In theory, this made the suit 

compatible with just about every modern jet 

bomber and fighter in the inventory, but 

there is little evidence the suit was used in 

many of those aircraft.46

On May 3, 1958, the configuration of the 

S794-6 suit to be delivered to Crossfield was 

frozen during a meeting in Worcester between 

representatives of David Clark Company, 

North American, and the USAF. The decision 

was somewhat premature since the suit 

configuration was still in question during a 

meeting 3 months later at Wright Field. This 

indecision had already resulted in a 2-month 

delay in delivery, and the need for further 

tests was apparent. Fortunately, in a perverse 

way, the entire X-15 program was running 

behind schedule, so the delay in the suit was 

not critical—yet.47

Nevertheless, the X-15 Project Office 

advised the newly assigned chief of the Aero 

Medical Laboratory, Col. John P. Stapp, that 

the suit delays might postpone the entire 

X-15 effort. To maintain the schedule, the 

X-15 program needed to receive Crossfield’s 

suit by January 1, 1959, a second suit by 

February 15, and the remaining four suits by 

May 15. Simultaneously, the X-15 Project 

Office confronted Stapp with a growing 

controversy concerning the use of a face seal 

instead of the neck seal preferred by the Aero 

Medical Laboratory.48

In a full-pressure suit, a mechanical separation 

is needed between the air space in the suit and 

the space surrounding the mouth and nose. 

To control the temperature within the suit, it 

is necessary to continually ventilate the free 

space between the suit and the wearer’s skin to 

carry off heat and water vapor, both of which 

rapidly accumulate to uncomfortable levels in 

an unventilated suit in the usual cockpit environment. Oxygen for breathing is carried aloft 

at considerable expense in terms of weight 

and space requirements. Before the advent of 

liquid oxygen systems, it was impractical to 

ventilate the suit with oxygen; therefore, the 

suit was usually ventilated with ambient air or 

nitrogen, and a seal separated the suit space 

from the breathing space.49

As with many things in life, the use of a face 

seal has some advantages and some disadvantages. Its chief advantage is the smallness of 

the breathing space and the resultant limited 

rebreathing. To obtain a truly satisfactory seal, 

the wearer’s face is pushed into a rubber seal 

by an adjustable harness behind the head. 

Such a method makes each helmet a truly 

personal piece of equipment, as some time 

is required to fit the seal properly to the face 

so that it is reasonably comfortable. With his 

face firmly held in the face seal, the wearer 

must move the entire helmet in order to turn 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

259

Jack McKay models an MC-2 suit. Note the orientation of 

the emergency oxygen cylinders in the back kit. Other photos 

show the cylinders running horizontally instead of vertically.

NASA

his head to either side. This is accomplished 

by rotating the helmet on its neck ring. Not 

only must the head be rotated in a fixed and 

somewhat unnatural plane, but movements 

are slow and difficult. An advantage, however, 

is that since most of the head is removed from 

the breathing space, it can be ventilated with 

the rest of the suit, generally increasing comfort. This arrangement became known as a 

conformal helmet.

The alternative to the face seal is a neck seal. 

With a neck seal, the head can be turned easily and naturally within the helmet. Properly 

constructed, a neck seal should be more comfortable than the face seal as the face must be 

continually pushed into relatively unyielding 

materials to produce an effective seal. Perhaps 

offsetting these advantages are the necessarily 

increased breathing space and poorer ventilation. The breathing space is increased both 

because the entire head is now in the oxygen 

space and also because the dome-type helmet 

that must be used with the neck seal is somewhat larger in the lateral (ear-to-ear) dimension than the face seal helmet to allow nose 

clearance when the head is turned. For most 

movements, the helmet remains stationary 

while the head turns inside it, although the 

wearer can manually turn the helmet with his 

hands if desired. The only ventilation of the 

head with the neck seal is coincident with the 

oxygen movement generated by breathing. 

This arrangement became known as a nonconformal (or dome) helmet.50

North American believed the pilot should be 

able to open the faceplate on his helmet, using 

the face seal as an oxygen mask. The Aero 

Medical Laboratory disagreed. Since engineers 

had long since agreed to pressurize the X-15 

cockpit with nitrogen to avoid risks associated 

with fire, a neck seal meant the pilot could 

never open his faceplate under any conditions. 

Eventually, the program adopted a neck seal 

for the MC-2 suit, although development of 

the face seal continued for the A/P22S-2 that 

came later.51

Subsequently, the X-15 Project Office found 

additional funds for the MC-2, and David 

Clark tailored eight suits for the individual 

X-15 pilots. These included Neil A. 

Armstrong (NASA), Scott Crossfield, Capt. 

Iven C. Kincheloe, Jr. (USAF, killed prior to 

his first X-15 flight), John B. “Jack” McKay 
236

Before he landed on the moon, Neil Armstrong was an X-15 

test pilot. During his 7 X-15 flights, Armstrong reached 

3,989 mph and 207,500 feet. The MC-2 suits were custom 

tailored for each X-15 pilot, necessitating several visits to the 

David Clark Company facility in Worcester, MA. Note the 

neck seal on the MC-2.

NASA

(NASA), LCDR Forrest S. Petersen (U.S. 

Navy), Lt. Col. Robert A. Rushworth (USAF), 

Joseph A. Walker (NASA), and Maj. Robert 

M. White (USAF). Each suit consisted of a 

ventilation garment, chloroprene-coated nylon 

twill upper and lower-torso gas containers, 

Link-Net upper and nylon lower-restraint 

garments, and a one-piece aluminized exterior 

cover. The neoprene-coated ripstop-fabric 

ventilation garment also included a porous 

wool-insulation layer. The upper and lower 

gas containers formed a seal at the waist by 

having their edges folded together three times. 

The lower gas containers incorporated a 

G-suit similar to standard USAF G-suits that 

provided protection up to about 7-G. The 

suit included a biomedical instrumentation 

pass-through that accommodated in-flight 

medical monitoring of the pilot. The helmet 

holddown system consisted of a steel cable 

that attached to the bottom of the helmet and 

ran through epaulets on the restraint layer.52

The exterior cover was not required for 

altitude protection, but the reflective 
237

NASA test pilot Joseph A. Walker made 25 X-15 flights. 

Although the MC-2 allowed X-15 flights to begin, David 

Clark Company was already working on the improved 

A/P22S-2, and ultimately only 36 of the 199 X-15 flights 

used the MC-2.

NASA

aluminized-nylon sunback-fabric cover contained the seat restraint, shoulder harness, 

and parachute attachments, and it provided a 

small measure of additional insulation against 

extreme temperature. It also protected the 

pressure suit during routine use and served as 

a sacrificial garment during high-speed ejection. This was among the first of the silver 

“spacesuits” that found an enthusiastic reception on television and at the movies.53

The X-15 provided gaseous nitrogen to pres-

surize the portion of the suit below the neck 

seal. The airplane also supplied the modified 

MA-3 helmet with 100 percent oxygen for 

breathing, and the same source inflated the 

G-bladders for acceleration protection. The 

total oxygen supply was 192 cubic inches, sup-

plied by two 1,800-psi bottles located beneath 

the X-15 ejection seat during free flight. The 

NB-52 carrier aircraft supplied the oxygen 

during ground operations, taxi, and captive 

flight. A rotary valve, located on the ejection 

seat, selected which oxygen source (NB-52 or 

X-15 seat) to use. The suit-helmet regulator 

automatically delivered the correct oxygen 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

262

pressure for the ambient altitude until absolute pressure fell below 3.5 psi (equivalent to 

35,000 feet); the suit pressure then stabilized 

at 3.5 psi absolute. Expired air vented into 

the nitrogen-filled suit through two one-way 

valves in the neck seal and then into the aircraft cockpit through a suit pressure-control 

valve. During ejection, the nitrogen gas supply to the suit below the helmet was stopped 

(since the nitrogen source was on the X-15), 

and the suit and helmet were automatically 

pressurized by the emergency oxygen supply 

located in the back kit.54

David Clark Company delivered the first 

flight-rated MC-2 full-pressure suit on 

December 17, 1958, just over 6 months later 

than originally planned. In a report dated 

January 30, 1959, the X-15 Project Office 

attributed much of the credit for the successful development of the full-pressure suit to 

Scott Crossfield.55

The number of details required to develop 

a satisfactory operational pressure suit were 

staggering. For instance, initially the MC-2 

suit used visors heated at 3 watts per square 

inch, but the conductive film overly restricted 

vision. The visors were heated for much the 

same reason as a car windshield: to prevent 

fogging from obscuring vision. The USAF 

gradually reduced the requirement to 1 watt 

in an attempt to find a compromise between 

heating the visor and allowing unimpeded 

vision. Tests in the cold chamber at the 

Aerospace Medical Center during late 

January 1961 established that 1-watt visors 

were sufficient for their expected use.56

Despite working reasonably well, pilots did 

not particularly like the MC-2 suit. It was 

difficult to don and doff, was cumbersome to 

wear, restricted movement, and had limited 

peripheral vision. It was also mechanically 

complex and required considerable maintenance. Nevertheless, there was only one serious deficiency noted in the suit: the oxygen 

line between the helmet and the helmetpressure regulator (mounted in the back kit) 

caused a delay in oxygen flow such that the 

pilot could reverse the helmet-suit differential 

pressure by taking a quick, deep breath. Since 

the helmet pressure was supposed to be greater 

than the suit pressure to prevent nitrogen 

from leaking into the breathing space, this 

pressure reversal was less than ideal, but no 

easy solution was available.57

The Air Force originally intended the MC-2 

as a true production full-pressure suit that 

would be used in all USAF aircraft that 

needed altitude protection, but that never 

happened. David Clark Company only 

fabricated a few suits beyond those procured 

by the X-15 program, mostly because 

something better was already in the works. 

Ultimately, only 36 of the 199 X-15 flights 

used the MC-2 suit.

A/P22S-2—PRODUCTION USAF 

FULL-PRESSURE SUITS

Although the MC-2 was usable for the initial 

X-15 flights, the USAF awarded David Clark 

Company a new contract to develop an 

improved pressure suit using what had been 

learned during the MC-2 effort. Charles C. 

Lutz was the Aeronautical Systems Division 

project officer, Maj. Richard G. Willis was 

the task engineer, and Joseph A. Ruseckas and 

Forrest R. Poole at David Clark Company 

were the principal designers.58 Ultimately, the 

A/P22S-2 became the first standardized fullpressure suit in the Air Force inventory, and it 

was the beginning of a line of suits developed 

by the David Clark Company for the CIA 

and USAF.

The suit would also be the first to use a new 

designation system. “A/P22S” was the prefix for a category called “Personnel Support 

Apparel” that would be used for standardized 

USAF full-pressure suits during the 1960s and 

1970s. There is no record of what A/P22S-1 

was assigned to (perhaps reserved for the 

MC-2), but the -2, -3, -4, and -6 designations 

would be used by full-pressure suits. Later A/

P22S designations would be used by “Extreme 

Cold Weather Survival Clothing Outfits.” 

Joe Ruseckas developed a mockup of the 

new suit based on the multi-layer MC-2 that 

included anti-exposure features, G-protection, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

263

and a ventilation system. The individual layers 

consisted of heavy long underwear, a ventilation garment, a gas container with integrated 

G-bladders, a restraint layer, and an insulated 

exterior cover with an integrated parachute 

harness. Ruseckas never intended this suit as 

a real prototype, but it provided David Clark 

Company a working model to evaluate and 

refine various features. In addition, David 

Clark Company further refined the Link-Net 

fabric for strength and flexibility.59

Similar to the MC-2, the chloroprene-coated, 

nylon-twill gas container was made in upper 

and lower torso sections with a roll-up seal 

at the waist. Cotton-flocked rubber gloves 

and boots were attached to the gas container. 

The entire restraint layer was made of nylon 

Link-Net, compared to only the upper half of 

the MC-2 restraint layer. Ruseckas and Poole 

redesigned the leg section of the restraint layer 

so that it would assume an optimum sitting 

position when pressurized without overly 

compromising the unpressurized sitting and 

standing positions, thereby allowing greater 

mobility and comfort. The helmet antilift 

arrangement consisted of the same shoulder 

epaulets and cables used on the MC-2. The 

aluminized-nylon sunback exterior cover had 

an integrated parachute harness, also similar 

to the MC-2. The full-pressure helmet was 

essentially identical to the MC-2 and attached 

to the suit using a rotating pressure-sealing 

neck ring.

Ruseckas started making major changes to the 

second suit. The heavy underwear was discarded in favor of light underwear with a fishnet fabric on the outside (away from the body) 

to allow a little space between the underwear 

and ventilation garment. The ventilation 

garment itself was modified by replacing the 

original inner layer of neoprene-coated ripstop 

fabric with oxford nylon and substituting 

Trilok synthetic fiber for the white embossed 

torso-fabric spacer layer. Ruseckas considered 

vent holes unnecessary since the oxford nylon 

was sufficiently porous to support the desired 

airflow. Neoprene-coated ripstop was used for 

the outer layer. This garment provided better 

airflow over the wearer and was significantly 

less bulky.

A new gas container used neoprene-coated 

nylon instead of chloroprene-coated nylon 

twill. The new fabric was woven with a 

smaller denier yarn and higher pick-count 

weave, and it offered less resistance (friction) 

when in contact with the restraint fabric, 

improving mobility because of its flexibility 

and slipperiness. Except for the shoulders 

and parts of the chest, which used Link-Net, 

Ruseckas made the restraint garment from 

marquisette. This was less Link-Net than on 

the MC-2, primarily because the fabric was 

difficult to fabricate and the expected largescale production of the A/P22S-2 demanded a 

simpler solution. The two-piece gas container 

joined at the waist gave way to a one-piece 

design with a U-entry zipper that started at 

the front of one shoulder, went under the 

arms and around the back, then ended on the 

front of the other shoulder. This arrangement 

became standard on all USAF full-pressure 

suits for the next decade.60

The exterior cover for the second suit consisted of two layers instead of one. The outer 

layer was high-tensile-strength black nylon, 

and the inner layer was a sage-green nylon 

sunback. This suit did not use an aluminized 

coating. David Clark Company made a new 

helmet based on a Bill Jack fiberglass shell. 

Ruseckas subjected the second suit, and the 

materials it was constructed from, to an extensive battery of tests to determine the strength 

and flexibility of each component.61

These evaluations led to improvements in 

the third prototype that reduced its bulk by 

30 percent. Ruseckas and Poole constructed 

the third suit primarily to investigate better 

ways to don and doff the garment. The designers replaced the six individual layers used in 

the earlier suits with only four layers that 

covered the torso to the neck, the arms to the 

wrists, and the legs, including the feet. The 

four layers included a nylon-oxford ventilation 

layer, gas container, restraint layer, and exterior 

cover. In this case, the cover was international 

orange nylon oxford. The separate ventilation 

garment and long underwear were eliminated.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

264

Sidebar: 

The 

Evolving

Pressure

Suit Depot

The original Physiological Support Division 

(PSD) was formed in 1957 at Edwards AFB, 

CA, by Col. John Paul Stapp, M.D., Ph.D. 

(1910–1999). As conceived by Stapp, the 

PSD would be a physiological research facil-

ity to complement the X-15 research airplane 

and subsequent high-speed and high-altitude 

programs. It was a grand plan that everybody 

supported, at least in public. However, by 

the time the Government finally authorized 

the PSD, Stapp had retired and gone on to 

other things and the facility was never used as 

originally intended. For instance, the facility 

included a large altitude chamber that Stapp 

wanted to use for evaluating pressure suits. 

Ultimately, however, it was mostly used to 

conduct routine physiological training. When 

support for the X-15 was being organized, the 

PSD was the logical organization to maintain, 

test, and repair the MC-2 pressure suits, in 

cooperation with the nearby NASA-FRC lifesupport shop managed by Roger Barnicki.62

As the Air Force began acquiring MC-2, 

A/P22S-2, and A/P22S-3 suits during the 

early 1960s, Air Force Headquarters had not 

given overall authority to any single organiza-

tion to control maintenance or logistical sup-

port or to track the flight safety of the suits 

to any single organization. The Air Defense 

Command (ADC) was the intended user of 

the majority of the suits, and in 1962, it estab-

lished a Physiological Training Unit at Tyndall 

AFB, FL. This organization was extremely lim-

ited in experience and facilities, and although 

it attempted to provide the best possible sup-

port, the condition of the suits deteriorated 

rapidly, necessitating the continual expansion 

of acceptable tolerances and a high rate of suit 

condemnation. However, by the end of 1967, 

the ADC had largely ceased using full-pressure 

suits and—excepting the special projects 

suits for classified programs—the primary 

users were the 58th Weather Reconnaissance 

Squadron at Kirtland AFB, NM, and the Air 

Force Flight Test Center (AFFTC) at Edwards 

AFB.63 Nevertheless, the Tyndall facility 

provided pilot training and pressure-suit 

maintenance, testing, and logistical support 

until 1976.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

265

By 1970, the AFFTC was lobbying to become 

the only USAF pressure-suit organization. 

Part of the argument was that it would then 

be possible to evaluate pressure suits at the 

same time as new aircraft were being tested at 

Edwards. The AFFTC also pointed out that 

no additional facilities would be required since 

a complete physiological support unit, labora-

tory, and altitude chamber already existed on 

the base.64 This finally occurred in 1976, when 

the Tyndall depot closed and all standard Air 

Force pressure-suit assets were consolidated 

at the Edwards PSD. This organization sup-

ported all high altitude flying at Edwards and 

the NASA-FRC, including the Aerospace 

Research Pilots School Test Pilot School and 

the XB-70A, YF-12, SR-71, and lifting bodies 

programs. The PSD also offered support for 

the British jerkin used by NASA-FRC for its 

high altitude F-15 and F-104 flights.65

In March 1972, the U.S. Department of 

Defense (DoD) designated the USAF, specifi-

cally the Life Support Special Project Office 

(LSPRO), as the lead DoD organization for 

all pressure-suit development, acquisition, and 

logistics support. The Navy, specifically the 

Naval Air Development Center in Warminster, 

PA, interfaced through the LSPRO to ensure 

its requirements were met. 

Of course, none of this affected the two primary users of pressure suits in the Air Force: 

the U-2 and SR-71 programs. The U-2 suits 

were always maintained wherever the airplanes 

were based: Groom Lake; Laughlin AFB, 

TX; North Base at Edwards; and then DavisMonthan AFB, AZ. The USAF established a 

PSD at Beale AFB in 1965 to support all 

SR-71 pressure suits and physiological training. In June 1976, U-2 operations moved 

from Davis-Monthan to Beale, and the two 

PSDs were consolidated at Beale. During 

the mid-1990s, the USAF closed the Edwards 

PSD and all U.S. pressure-suit activities, 

excepting Space Shuttle operations, were 

consolidated at the Beale PSD to support 

the USAF U-2 program, as well as the 

NASA WB-57F and ER-2 programs.66
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

266

One of the major improvements introduced on the A/P22S-2 

was a U-shaped entry zipper that started at the front of one 

shoulder, went under the arm, around the back, and then 

ended on the front of the other shoulder. There was also a 

smaller relief zipper over the crotch.

Courtesy of the David Clark Company, Inc.

The pilot entered the suit through a U-entry 

pressure-sealing slide fastener, and there was a 

7-inch relief zipper installed over the crotch. 

Leather boots were integrated into the garment using separating slide fasteners. The 

helmet holddown straps were 0.75 inch nylon 

webbing anchored to the restraint layer at the 

groin lines on each side of the relief zipper and 

at the center back just above the main entryslide fastener.

The designers attempted to produce one-piece 

detachable gloves that would be sufficiently 

flexible and pliable at 3.5 psi to allow the pilot 

to perform all the functions expected of him. 

Four different designs were produced, but 

none was truly satisfactory. The company also 

produced a new helmet with a fiberglass shell 

and plexiglass visor and sunshade. Unusually, 

the visor was automatically lowered at the 

pressure equivalent of 9,100 feet altitude. It 

was later modified to allow the pilot to lower 

the visor below that altitude if needed. When 

the visor sealed shut, it actuated the regulator that pressurized the helmet and provided 

breathing oxygen. The breathing regulator and 

all plumbing were installed inside the helmet 

shell, with a spray bar around the periphery 

of the visor that defogged the visor. A face 

seal separated the front of the helmet from 

the back, and the back compartment was 

pressurized with the suit, separately from the 

breathing space in the front of the helmet. 

Adjustable chamois-covered foam ear pads 

allowed individual fitting to each pilot. The 

basic helmet design, and many of the details, 

was copied directly from the Navy-Goodrich 

Mark II helmet.67

The third prototype weighed 19.25 pounds, 

including the suit, helmet, gloves, and 

boots. Joe Ruseckas delivered the suit to the 

Aeronautical Systems Division at WrightPatterson AFB on April 23, 1959, to undergo 

formal testing. The Air Force took the suit to 

Edwards on July 27, 1959, for flight-testing, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

267

using the same JTF-102A that had been used 

to evaluate the MC-2. While the suit was at 

Edwards, several of the X-15 pilots evaluated 

it and made suggestions for minor improvements, although all thought it much improved 

over the MC-2. The USAF approved the suit 

on October 19, 1959.68

Despite the USAF approval, Joe Ruseckas 

believed the suit could be further improved. 

He developed a fourth prototype that more 

closely conformed to the eight-size tariff then 

in vogue. Ruseckas redesigned the torso to 

reduce bulging in the back when the suit was 

pressurized, and he added laces at the shoulder 

area to permit some tailoring to individual 

pilots. Laces were also added at the forearm, 

calf, and around the waist. He extended the 

U-entry zipper farther up the shoulders to 

make the suit easier to don and lessen the 

stress across the chest.

In addition, David Clark Company changed 

the exterior cover from nylon oxford to 

Duplan Weatherbar polyurethane-coated 

nylon because it was water resistant and could 

serve as a wind-breaker. The helmet received 

numerous interior changes to provide more 

room and improve comfort. Ruseckas added 

an anti-suffocation feature to the helmet 

that would automatically open the visor if 

there were no oxygen flow for 90 seconds. 

During those 90 seconds, the pilot would 

have increasing difficulty breathing, triggering 

a warning to descend to a lower altitude. 

Finally, David Clark Company succeeded in 

permanently positioning a flocked rubber 

glove inside a leather outer glove, providing 

a flexible glove for the suit. Testing in 

Worcester showed the new suit had a leak rate 

of 0.5 liters per minute (lpm) at 5 psi, and the 

helmet leaked at 0.7 lpm, giving a total of 

1.2 lpm for the entire ensemble. The suit and 

helmet could withstand an internal pressure 

of 6 psi for 15 minutes without failing, well 

above the 3.5 psi operating pressure.69

David Clark Company delivered the fourth 

prototype to the Aeronautical Systems Division 

on October 25, 1960, for evaluation. After 

tests in the altitude chamber, centrifuge, and 

environmental chamber, the Air Force took the 

suit to Edwards for flights in the JTF-102A. 

Although the Air Force would not formally 

approve the suit for use until July 3, 1961, it 

told David Clark Company to manufacture a 

small quantity of service-test suits, including 

custom-fitted versions for X-15 pilots Maj. 

Robert A. “Bob” Rushworth, Joseph A. “Joe” 

Walker, and Maj. Robert M. “Bob” White.

NASA test pilot Joe Walker made the initial 

attempt at using the A/P22S-2 in the X-15 

on March 21, 1961; unfortunately, telemetry 

problems caused the launch attempt (2-A-27) 

to be aborted. Nine days later, Walker made 

the first flight (2-14-28) in the A/P22S-2 and 

reported the new suit represented a significant 

improvement in comfort and vision over the 

MC-2. By the end of 1961, the A/P-22S-2 

had a total of 730 hours in support of X-15 

operations; these included nine X-15 flights, 

171 flight-hours in the JTF-102A, and 

554 hours of ground time. It is interesting 

to note that although the X-15 pilots were 

still somewhat critical of the lack of mobility 

afforded by the full-pressure suits (particularly later pilots who had not experienced the 

MC-2), this was only true on the ground. 

When the suits occasionally inflated for brief 

periods during flight, an abundance of adrenaline allowed the pilot to easily overcome the 

resistance of the suit. At most, it rated a slight 

mention in the postflight report.70

By mid-1961, 61 individuals had tested the 

A/P22S-2 at simulated altitudes ranging from 

7,000 to 100,000 feet. The suit had successfully passed explosive-decompression tests in 

altitude chambers at 35,000 and 65,000 feet. 

In a particularly demanding test, a mannequin 

wearing the suit was ejected from the back 

seat of a Convair F-106B Delta Dart flying at 

22,500 feet and 730 knots (Mach 1.58), providing a maximum dynamic pressure (Q) of 

1,580 pounds per square foot. The Air Force 

conducted three rocket-sled tests at Edwards 

using the suit—two using an X-15 ejection 

seat and one using an F-106 seat—ranging 

from 0.68 to 1.08 Mach (650 to 1,615-Q). 

The USAF formally approved the suit on 

July 3, 1961.71
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

268

The A/P22S-2 was clearly superior to the 

earlier MC-2, particularly from the pilot’s 

perspective. Some of the improvements 

included:72

Increased visual area: The double curvature 

faceplate in the A/P22S-2, together with the 

use of a face seal in place of the MC-2 neck 

seal, allowed the face to move forward in the 

helmet so that the pilot had a lateral vision 

field of approximately 200 degrees. This was 

an increase of approximately 40 degrees over 

the single contoured lens in the MC-2 helmet, 

with an additional increase of 20 percent in 

the vertical field of view.

Ease of donning: The MC-2 was donned in 

two sections: the lower rubberized garment 

and its restraining coverall, and the upper 

rubberized garment and its restraining coverall. This was a rather tedious process and 

depended on folding the rubber top and 

bottom sections of the suit together to retain 

pressure. The A/P22S-2 was a one-piece garment with a U-entry pressure-sealing closure 

that was zippered closed in one operation. It 

took approximately 30 minutes to properly 

don an MC-2; it took only 5 to 10 minutes to 

don the newer suit.

Removable gloves: In the MC-2, the gloves 

were permanently attached to the upper 

rubberized garment. The A/P22S-2 had 

removable gloves that contributed to general 

comfort and ease of donning. Removing the 

gloves also prevented excessive moisture from 

building up during suit checkout and preflight 

inspections, and it made it easier for the pilot 

to doff the pressure suit by himself if that 

should become necessary. Another advantage 

was that a punctured glove could be changed 

without having to replace the entire suit.

Of special interest to the X-15 program, the 

A/P22S-2 featured new biomedical electrical 

connectors installed through a pressure seal in 

the suit, avoiding the snap-pad arrangement 

used in the MC-2 suit. The snap pads had 

proven to be unsatisfactory for continued use; 

after several operations, the snaps either separated or failed to make good contact because of 

metal fatigue. This resulted in the loss of biomedical data during the flight. In the new suit, 

biomedical data was acquired through what 

was essentially a continuous electrical lead 

from the pilot’s body to the seat interface.73

The standardized A/P22S-2 ensemble consisted of the CSK-6/P22S-2 coverall, HGK13/P22S-2 helmet, and HAK-3/P22S-2 

gloves.74 David Clark Company called these 

S926 (with an altimeter on the thigh) and 

S926A (without the altimeter).75 The suit was 

fabricated in the now-standard eight sizes, 

although the arms, legs, and torso contained 

covered laces that could be adjusted to tailor 

the suit as needed. The X-15 suits (S906 

and, later, S940) were still custom fitted to 

The A/P22S-2 air inlet and suit controller was on the 

right side of the suit and the air exhaust was on the left. 

Note the diagonal zippers for the U-shaped entry. Joe 

Ruseckas is wearing the suit while sitting in an ejection 

seat used for fittings. 

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

269

The David Clark Company facility at 360 Franklin Street in 

Worcester, MA. Most pressure suit fabrication takes place in the 

portion of the building fronting Franklin Street (foreground), 

with the remainder of the facility supporting the company’s 

noise-attenuating headset and intercom business.

Courtesy of the David Clark Company, Inc.

each pilot. The helmet came in a single size, 

although 3 sizes of crown pad were available, 

and the gloves came in 12 sizes. The suit was 

manufactured to specification MIL-F-27628.76

The A/P22S-2 helmet used an electrically 

heated stretched-acrylic visor procured from 

the Sierracin Corporation. The early visors 

had the electrically conductive coating applied 

to the inside of the acrylic, and the coating was not particularly durable, requiring 

extraordinary care during handling. David 

Clark Company eventually solved this with 

the introduction of a laminated heated visor, 

where the electrical heat element was sandwiched between two layers of acrylic. This 

required a new development effort since 

nobody had laminated a heated double-curvature lens, although Protection Incorporated in 

Los Angeles had done some preliminary work 

on the idea at company expense. David Clark 

Company supplied laminated visors with later 

models of the A/P22S-2 suit.77

Another requirement came via an unusual 

source: Project Excelsior. Researchers evaluating the effects of the high-altitude free fall 

during Joe Kittinger’s record balloon jump on 

August 16, 1960, realized that the X-15 pilot 

would need to be able to see after ejecting 

from the airplane. This involved adding a battery to the seat to provide electrical current for 

visor heating during ejection.78

Despite its tremendous improvements over 

the MC-2, the A/P22S-2 was not perfect 

and Joe Ruseckas modified the suit based on 

initial X-15 flight experience. The principal 

changes included improved manufacturing, 

inspection, and assembly techniques for the 

helmet ring to lower the force required to 

connect the helmet to the suit, as well as the 

installation of a restraint zipper that removed 

the structural load from the pressure-sealing 

closure to lower the leak rate of the suit. Other 

changes included the installation of a double 

face seal, to improve comfort and minimize 

leakage between the breathing space and suit, 

and modifications to the tailoring of the LinkNet restraint garment around the shoulders to 

improve comfort and mobility. David Clark 

Company also solved a weak point involving 

the stitching in the leather glove by including 

a nylon liner that relieved the strain on the 

stitched leather seams.79

Around this time, Sears, Roebuck and Co., 

a major David Clark Company customer 

for its “Sears Best” brassieres, cancelled its 

contract with David Clark Company due 

to a dispute over access to cost-accounting 

data. This presented David Clark Company 

management with a challenge to keep its 

workforce employed. Fortunately, within 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

270

The front door to the David Clark Company shows the 

understated presence the company has maintained for 

decades. Much of the original wartime development of 

G-suits and early pressure suits was accomplished on 

handshakes or using company funds. The company 

continues the tradition of providing the best possible 

value to its customers, and is the last remaining Western 

pressure suit manufacturer.

Dennis R. Jenkins

a short period, the company won a NASA 

contract to develop the Gemini spacesuit and 

won a contract with the Air Force to develop 

the Dyna-Soar spacesuit. This all happened 

as the company was completing its move 

from rented space on Webster Street and Park 

Avenue into its own building on Franklin 

Street, all in Worcester.80

When the Air Force initiated the development 

of the A/P22S-2 in 1958, it had grand ambitions that almost all of its fighter and bomber 

pilots would be wearing full-pressure suits 

as they soared through the stratosphere. The 

initial production contract with the David 

Clark Company included provisions for the 

eventual delivery of “thousands” of suits, and 

the company procured the material necessary 

to fabricate this large quantity. Ultimately, of 

course, reality set in and the Air Force realized that although it was procuring aircraft 

capable of flying at 50,000 or 60,000 feet, 

very few flights actually went that high. In 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

271

the end, only about 500 A/P22S-2 suits were 

produced, leaving the company with a huge 

supply of surplus material.81

Shortly after the suit was approved for operations, other organizations began looking at the 

suit to fill their needs. The original Lockheed 

U-2 models used a partial-pressure suit for 

their entire careers, mostly because the cockpit 

was too small to reasonably accommodate a 

full-pressure suit. That did not mean the idea 

was not investigated. One of the operating 

bases for the U-2 was Patrick AFB and the 

heat and humidity of central Florida caused 

certain problems. Most missions required a 

minimum of 50 minutes of oxygen prebreathing, including at least 20 minutes in an ambient atmosphere after the pilot entered the 

cockpit and was strapped in, and the airplane 

was pulled out of the hangar and readied for 

engine start. These conditions caused excessive 

heat fatigue for the pilot in a partial-pressure 

suit, and some pilots perspired intensely 

enough to obstruct their vision.82

Major Harry Andonian, chief of the Special 

Projects Operations Branch of the Air Force 

Flight Test Center at Edwards and a former 

U-2 test pilot, ordered an evaluation of using 

the new A/P22S-2 in a U-2. Captain Budd F. 

Knapp conducted the evaluation at Edwards 

using a suit borrowed from the X-15 program. 

Knapp noted that the X-15 suit included 

G-protection that would not be required on 

U-2 missions, and this added a small amount 

of bulk to the suit.

On November 14, 1961, Maj. Ralph N. 

Richardson, chief of the Physiological Support 

Division at Edwards, provided a ground 

demonstration in the U-2 for Knapp at the 

detachment on North Base. Even inflated at 

5 psi, Richardson, who was 6-feet, 2-inches 

tall and weighed 195 pounds, could reach all 

of the essential switches and controls in the 

U-2 cockpit. Two days later Knapp had an 

altitude chamber run to 125,000 feet, and on 

November 28, Knapp had a familiarization 

flight in the JTF-102A that he indicated, 

“... added little to the evaluation... but 

was required by regulation.”83 He found 

the suit easier to get into than the MC-3 

partial-pressure suit normally worn, with 

the entire donning process taking less than 

5 minutes. The suit had two pressurization 

levels available: 5 psi, which maintained 

the equivalent of 27,000 feet, and 3.5 psi, 

equivalent to 35,000 feet. Both offered more 

protection than the 45,000-foot equivalent 

skin pressure afforded by the MC-3 partialpressure suit.

The modifications to the U-2 to accommodate 

the A/P22S-2 were few and simple to implement, mostly bringing high-pressure oxygen 

to the correct location to connect to the suit 

and an electrical connection for the visor heat. 

On November 30, 1961, Knapp flew a 3-hour 

and 15-minute flight in a U-2 while wearing 

the A/P22S-2 inflated to 5 psi. Unlike flights 

using the MC-3, prebreathing prior to the 

flight was not required with the full-pressure 

suit. The flight reached a maximum altitude 

of 50,000 feet and replicated a typical weather 

mission that required operating switches at the 

cockpit extremities. Knapp “failed” the cabin 

pressurization at 49,000 feet and reported 

“mobility is not as good as the partial-pressure 

suit at this altitude.”84 The pilot reported, 

however, that based on his altitude chamber 

flight, the A/P22S-2 offered superior mobility 

Captain Robert M. White, an X-15 pilot, showing off a 

non-X-15 version of the A/P22S-2. Note the backpack 

parachute and the seat kit that were intended for use in 

operational aircraft such as the Convair F-102 Delta 

Dagger and F-106 Delta Dart interceptors.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

272

above 55,000 feet. Knapp reported that visibility was much better in the A/P22S-2 than 

the MC-3. 

Knapp flew a second flight on February 15, 

1962, at the “peak performance altitude” 

of the U-2 with the suit inflated to 3.5 psi. 

After this flight, Knapp reported that on both 

flights, he could, with some effort, reach the 

defrost fan switch located on the extreme rear 

of the left console.

Knapp noted that oxygen consumption was 

about double using the A/P22S-2, and he 

indicated that the second flight, which had 

been planned for 8 hours, was terminated 

after 5.5 hours when the oxygen supply was 

depleted. In general, Knapp characterized the 

A/P22S-2 as more comfortable than the partial-pressure suit, but he criticized the helmet 

and gloves. The helmet issue appeared to be a 

fit problem, but Knapp noted the gloves did 

not seem to provide any ventilation for the 

hands, resulting in excessive perspiration. In 

addition, it was difficult to manipulate some 

switches when the gloves were inflated.

In the end, Knapp reported that the A/P22S-2 

was “not acceptable at this time for all around 

mission accomplishment in the U-2.”85 This 

was based largely on the oxygen-consumption 

rate that would not allow operational missions to be flown. Nevertheless, Knapp 

thought the full-pressure suit offered promise 

and suggested a continuing evaluation. It is 

unclear if this ever took place, but the original 

U-2 models used partial-pressure suits until 

they were finally retired in 1989.

Back to the suit’s intended users, in late 1961 

the Air Defense Command (ADC) conducted 

a comparative test of full-pressure suits and 

concluded that the A/P22S-2 met its needs 

better than the A/P22S-3 (Navy-Goodrich 

Mark IV). The relative merit of the Navy suit 

was a subject that would not go away and 

several other evaluations would take place 

over the next few years.86

At the end of 1961, David Clark Company 

introduced the S931 model, intended specifically for the F-106 interceptor. This suit 

included a side zipper at the waist; helmet 

holddown straps that were anchored on the 

back of the suit, and a new adjustment on the 

front of the suit; reconfigured neck and wrist 

rings; ventilation for the feet; relocated controller and vent fittings; and gloves that used 

Link-Net on the back.87

The minor improvements of the S931 notwithstanding, as early as March 13, 1962, the 

ADC recommended the Air Force undertake 

an effort to develop an improved A/P22S-2. 

Primary among the improvements desired by 

the ADC was to alleviate the glare and reflection from the inner surface of the helmet 

sunshade and visor, include a warning device 

to indicate a loss of pressure in the visor seal, 

and improve the ease of connecting the wrist 

and neck rings. In addition, the ADC wanted 

a lighter, more durable suit that was easier 

to don and doff, with a more reliable pressuresealing zipper. The gloves were singled 

out for improvement in dexterity, comfort, 

and durability.88

As he prepared to retire in 1962, David Clark, 

the man, gave a percentage of the David Clark 

Company to the College of the Holy Cross 

in Worcester. Holy Cross is the oldest Roman 

Catholic college in New England and one of 

the oldest in the United States. Finally, to raise 

capital for the company before he left, Clark 

sold his remaining share to Munsingwear, to 

which he had already sold a major interest. 

The sale to Munsingwear had little effect on 

the operations of the company, other than 

providing a needed boost in capital. By 1965, 

Munsingwear had acquired the Holy Cross 

portion of the company also.89

In 1975, Clark’s successor as president, John 

E. Flagg, along with company Treasurer 

Darald Libby and a few senior managers, 

bought David Clark Company back from 

Munsingwear. Ownership has remained 

within the company ever since, with a 

combination of senior management and 

employee stock ownership plans. As of 2009, 

David Clark Company was a 100-percentemployee-owned business. The employees 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

273

Excepting the X-15 program, this was the standard operational configuration of the A/P22S-2 suit with a parachute 

and a seat kit that held the suit support systems and emergency oxygen. The X-15 used a back kit instead of a seat kit. 

Note the spurs on the back of the boots that were used to lock 

the pilot’s feet in the ejection seat to keep his legs from flailing 

as he left the airplane.

Courtesy of the David Clark Company, Inc.

believe the significance of this ownership 

heritage is that each successive generation of 

owners has come from within the company 

and chosen to perpetuate the continuous 

advancement of pressure-suit-related 

technologies that David Clark initiated 

during the 1940s. Executive Vice President 

Jack Bassick opined that, “each generation of 

owners-managers has remained interested and 

in touch with the company throughout their 

entire lifetimes. We are presently transitioning 

from the third to the fourth generation 

of senior management, with my (third) 

generation being the last one to have known 

Dave personally.”90 It has obviously worked 

well since David Clark Company has been the 

primary (and, often, only) supplier of pressure 

suits in the United States.

In February 1963, the ADC conducted an 

operational evaluation using A/P22S-2 suits 

in a two-seat Convair F-106B Delta Dart 

interceptor. Ten flights were conducted from 

10 different USAF bases that totaled about 

23 hours of flight time, all flown by Maj. 

Edward W. Kenny and Capt. Robert I. 

Platenberg. Both pilots had limited experience 

in the MC-3 and MC-4 partial-pressure suits 

prior to the evaluation. In general, the pilots 

found the A/P22S-2 comfortable, but both 

complained about the lack of ventilation in 

the gloves and reported that their hands perspired excessively. Unusually, the pilots took 

matters into their own hands, literally, and 

each purchased a pair of nylon insert gloves 

that they wore under the pressure gloves. They 

reported that this substantially eliminated the 

perspiration problem. The pilots indicated 

that the faceplate defogging system worked 

very well, even at Duluth AFB and Loring 

AFB, where the temperature was well below 

zero. They made one landing at the Colorado 

Air National Guard Base at Buckley Field, 

CO, expressly to determine what difficulties 

would be encountered landing at a base with 

no facilities or experience with pressure suits. 

According to the pilots, “no major problems 

were evidenced.”91

In general, the pilots found no substantial 

faults with the A/P22S-2 during their whirlwind tour. Excepting the perspiration issue 

with the gloves, the list of complaints was 

small. For instance, the helmet had to be fitted 

carefully to avoid discomfort, the knife pocket 

on the left leg restricted stick movement and 

should be moved, care had to be taken when 

reaching for some controls since the wrist rings 

might accidently actuate the wrong control, 

and the visor did not adequately eliminate 

glare on the radar scope. During the 10 flights, 

the crew spent between 3 hours, 30 minutes 

and 12 hours, 15 minutes in the suits every 

day without major complaint. Overall, the 

evaluation concluded that “aircrews can wear 

the A/P22S-2 with the minimum amount of 

discomfort, accomplish the assigned mission, 

and still be afforded the protection that the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

274

full-pressure suit will provide.”92 Nevertheless, 

the ADC wanted several modifications.

In response, on March 1, 1963, the USAF 

awarded the David Clark Company a contract 

to develop the improved A/P22S-2A version 

of the full-pressure suit. Joe Ruseckas began 

working on the new suit on April 4, 1963, 

and delivered an improved helmet visor to the 

USAF on January 13,1964, with the rest of the 

suit following 10 days later. The A/P22S-2A 

differed from earlier versions by having a larger 

helmet that included commercial radio equipment compatible with the AIC-10A standard 

and rearranged pressurization and oxygen controls. Improved gloves used different materials 

and eliminated the slide fasteners in favor of 

two adjustment straps. The outer layer now 

had a black leather palm and fingers and an 

aluminized-nylon back and wrist. The coverall 

incorporated a B.F. Goodrich pressure-sealing 

slide fastener in the crotch area that served as a 

relief opening. The knife pocket was relocated 

based on numerous pilot comments about it 

restricting control stick movement, the helmet 

ring and latch were sturdier, and the wristattach rings were redesigned to be simpler and 

more reliable. The resulting suit was slightly 

heavier than the standard A/P22S-2—20.

12 pounds compared to 19.95 pounds. This 

was a little deceptive since the coverall was 

almost 2 pounds lighter than the earlier version, but the helmet was 2 pounds heavier. 

Testing and evaluation of the A/P22S-2A 

determined that the new suit “shows some 

improvement” but that “further improvements 

are required to make the outfit more operationally acceptable.”93 There is no record that 

this version of the suit entered production or 

was issued to operational squadrons.

As late as July 1963, the Tactical Air 

Command (TAC) was still evaluating the 

relative merits of the A/P22S-2 and the A/

P22S-3 (Navy-Goodrich Mark IV). In 

addition to the two American full-pressure 

suits, the tests also compared the RAF jerkin 

pressure vest that only covered the torso and 

crotch. The jerkin was donned through a 

sliding fastener running from the center of the 

neck down to the front of the left leg. It was 

possible to don the jerkin in a few seconds, 

versus the 5 minutes it took to get into either 

of the full-pressure suits. The jerkin used a 

blue-gray Terylene outer fabric and a bluegray nylon inner layer. Between the two fabric 

layers was a textured rubberized silk bladder 

that completely inflated the jerkin except for 

a small portion of the buttock and the small 

of the back. The jerkin had to be used with a 

pressure-breathing oxygen mask and was worn 

over a standard G-suit.94

Joe Ruseckas and Robert R. “Bob” Banks 

from David Clark Company witnessed some 

of the tests and were surprised about the 

inclusion of the Navy suit since they believed 

the USAF had already eliminated that suit 

from contention a year earlier. The purpose 

of this particular test was to determine which 

suit would be best suited for use in the new 

McDonnell F/RF-4C Phantom II, in particular, how much infrastructure was required 

to support full-pressure suit operations. The 

Navy was already using the Mark IV suit 

in the F-4B version of the aircraft. The test 

order pointed out that while the Navy generally operated from established shore bases or 

well-equipped aircraft carriers, and the ADC 

operated from bases in the continental United 

States, the TAC routinely operated from austere bases in other countries.95

Col. Frank K. “Pete” Everest and Capt. Stanley 

G. Sprague flew the tests from the 4453rd 

Combat Crew Training Squadron at MacDill 

AFB, FL on July 16–17, 1963. Since the 

USAF F-4C was not yet available, the tests 

used one of the 47 Navy F-4Bs operated by the 

4453rd. Like most early F-4Bs, these aircraft 

were equipped to use the Mark IV pressure suit 

but were easily adapted to use the A/P22S-2. 

The test determined that the A/P22S-2 better 

suited the USAF requirements than the Navy 

or RAF garments, but it also resulted in a 

rather long list of relatively minor changes that 

could improve the A/P22S-2.96

The search for an improved suit continued, and in August 1964, the David Clark 

Company began developing the A/P22S-2A 

(Mod 1) suit. The first article was delivered 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

275

David Clark Company 

fabricated special versions 

of the A/P22S-2 for the 

NASA and Air Force lifting 

body programs. This 

is NASA test pilot William 

H. Dana standing in front 

of the HL-10 lifting body 

on one of the dry lakes at 

Edwards AFB, CA. Note the 

portable air-conditioning 

unit attached to the suit 

to keep Dana cool in the 

High Desert. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

276

Bill Dana being interviewed following the last flight of the 

X-24B lifting body on September 23, 1975. The David 

Clark Company had agreed to supply NASA with white 

A/P-22S-2 pressure suits and black boots for the lifting body 

pilots. At his fitting, Dana found his suit had white boots, 

which he opined were not sufficiently masculine for a test 

pilot. “I might as well wear pink boots,” he said, a comment 

that was not lost on the David Clark technicians. When 

Dana’s suit was delivered, it came with standard black boots. 

However, the David Clark technicians, remembering the 

earlier comment, also provided a second pair—pink with 

adhesive flower decals. To his credit, Dana wore the boots 

on his next HL-10 flight and again during his final X-24B 

flight. Great test pilots have a sense of humor, even at their 

own expense.

NASA

to the USAF in May 1965. The suit used a 

monolithic, conductive-coated visor that was 

similar to the one used during the X-15 program, and the visor and sunshade knobs were 

reworked to provide better tactile feedback 

when moved. The top back of the helmet 

contained an exhaust valve developed for the 

Navy Mark IV suit, and a new suit controller, 

developed by Firewel for the Mark IV, was 

mounted on the right-front center of the coverall. Improved gloves had white leather palms 

and fingers, and the index finger outseam was 

moved to the back of the finger to provide a 

better sense of feel. The inside of the gloves 

were lined from the wrist to the base of the 

thumb and fingers with a chloroprene-coated 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

277

Air Force pilots assigned to the lifting body programs also 

wore the custom white A/P22S-2 suits with black boots. 

From left are Maj. Jerauld R. Gentry, Maj. Peter C. Hoag, 

John A. Manke, and William H. Dana. Note the Air 

Force pilots have an Air Force Flight Test Center 

(AFFTC) patch on their suits, while the NASA pilots 

have a NASA “meatball.”

NASA

ripstop nylon liner to distribute ventilation 

air. The wrist ring was modified with a rotating bearing to provide more mobility. The 

material in the outer layer was changed to 

provide better mobility, and the pockets were 

moved to the front of the legs so they did not 

interfere with the control stick or other items 

in the cockpit.97

Air Force evaluation of the A/P22S-2A 

(Mod 1) did not show any marked 

improvement over the earlier suits. In particular, the results showed no particular difference 

in the efficiency of the ventilation system. 

Surprisingly, in some tests, the (Mod 1) suit 

appeared to inhibit mobility more than the 

standard suit. The new gloves, and a similar 

change to the socks, were not particularly successful and were “not considered practical at 

this time.”98 The rotating wrist bearing would 

find use on the special A/P22S-2 suits (S935) 

fabricated for the NASA lifting-body program 

but would otherwise have to wait until the 

much later S1034 to be included on a standardized USAF full-pressure suit. Like the 

A/P22S-2A before it, the (Mod 1) suit did 

not enter production.

Production of the A/P22S-2 continued, 

albeit at rates far below the original estimates. 

Although the USAF designation did not 

change, the David Clark Company model 

numbers changed frequently and included: 

S906 (X-15), S926, S931, S934, S935 (NASA 

lifting bodies), S940 (X-15), S963, S971, 

S998 (X-15), S1016, and S1027 (X-15). The 

S935 featured a different method to exhaust 

pressurization air to make it compatible with 

the lifting bodies, and it used the rotating wrist 

ring originally developed for the (Mod 1) suit. 

The custom-fitted X-15 suits used a thicker 

visor and a different visor-heat system, as well 

as a back kit instead of a seat kit so they could 

be used with the X-15 ejection seat. The final 

S1027 suits fabricated at the end of the X-15 

program were custom fitted for NASA test 
278

The vast majority (163 of 199) of flights of the hypersonic 

North American X-15 research airplane used A/P22S-2s 

instead of the original MC-2 suits. The pilots found the 

newer suit to be much more comfortable. Interestingly, even 

pilots that complained about restricted mobility when the 

suit was on the ground seldom mentioned it when they were 

faced with using it in flight. Adrenalin is a wonderful thing. 

Note the “mission marks” on the back of the life-support 

van. Unlike the standardized A/P22S-2, the X-15 suits were 

custom tailored for each pilot. 

NASA

pilots William H. Dana and John A. Manke, 

and for Air Force pilots Maj. Michael J. Adams 

and Maj. William J. “Pete” Knight.99

On November 22, 1968, an F-104C crashed 

near Mojave while on a training mission, 

killing Maj. Kermit L. Haderlie, a student 

from the USAF Aerospace Research Pilots 

School (ARPS) at Edwards. For students at 

the ARPS, the zoom climb was a rehearsal 

for possible future spaceflight. The pilots 

always wore A/P22S-2 suits since the Mach 2 

climb continued until the General Electric 

J79 engine flamed out, which deprived the 

cockpit of pressurization. The Air Force 

accident board determined that a “design 

deficiency” in the suit wrist ring allowed an 

“inadvertent disconnection” of Haderlie’s 

glove while he was at altitude.100
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

279

Air Force suit-donning procedures originally 

required the glove-locking ring to be taped 

over to increase the force required to move the 

sliding lock and thus reduce the possibility of 

an inadvertent unlocking. Oddly, in the spring 

of 1968, taping was removed from the donning procedure. On his fatal flight, Haderlie 

reported his pressure suit inflated as expected 

while passing through 50,000 feet. However, 

as he reached 63,000 feet, Haderlie reported 

“I lost my glove,” and the Starfighter began 

tumbling.101 The accident report indicates the 

F-104 reached 69,400 feet before it began an 

inverted dive toward the desert. At the time 

of the accident, the USAF had more than 

400 A/P22S-2 suits in inventory. 

Because of the impending 60-month servicelife expiration of the A/P22S-2 assemblies, 

in early 1967 the Air Force had initiated a 

program to develop an improved suit. Joe 

Ruseckas and the rest of the David Clark 

Company went back to the drawing board. 

By this time, David Clark Company was well 

into the development of the spacesuits for 

Gemini and Dyna-Soar and had gained considerable experience with the “special projects” 

(Lockheed A-12 and SR-71 Blackbird) suits. 

Ruseckas felt it “desirous to investigate these 

for possible incorporation.”102 The designers 

at David Clark Company conducted numerous experiments and came up with a variety 

of improvements for a suit that the USAF 

subsequently designated A/P-22S-4.

A/P22S-3—A NAVY SUIT FOR THE 

AIR FORCE

The Air Force decision not to field the 

MC-2 in great numbers and to develop the 

A/P22S-2 suit delayed the introduction of 

a full-pressure suit to operational units. The 

ADC, in particular, was not happy about this 

turn of events, so in May 1960, the USAF 

procured a small number of the Goodrich 

Mark IV full-pressure suits developed for 

the Navy. The suits were procured by the 

Navy under contract N383(MIS)165773 

and designated A/P22S-3 in USAF service. 

It appears that Goodrich manufactured all 

A/P22S-3 suits and that no Arrowhead suits 

were used by the Air Force. The first eight Air 

Force suit technicians from the 4756th Physiological Training Flight at Tyndall AFB, FL, 

arrived at the Goodrich plan in Akron in early 

May 1960 for indoctrination.103

The A/P22S-3 suit was generally similar to the 

Mark IV except for different communication 

and oxygen hose connectors, a different suit 

regulator, and a short hose pigtail attached to 

the suit to reach the USAF aircraft connectors. In addition, the standard Mark IV helmet 

was painted white with a USAF wing decal 

(instead of being gold with a Navy decal), and 

the restraint layer was international orange 

instead of olive drab. Since the suits were being 

procured primarily for the ADC, the A/P22S-3 

did not include the normal G-suit connections 

(the Mark IV used a standard G-suit under the 

full-pressure suit).104

Despite the late-1961 evaluation that concluded that the A/P22S-2 was the preferred 

suit, the ADC conducted another evaluation 

in mid-1962. This “Comparative Test of 

Aircrew Pressure Suits” evaluated the David 

Clark A/P22S-2 and the Goodrich A/P22S-3 

full-pressure suits alongside the CSU-4/P and 

CSU-5P partial-pressure suits.105

The ADC selected the 325th Fighter 

Interceptor Squadron at Truax AFB near 

Madison, WI, to conduct the evaluation. 

Six pilots from the squadron each wore all 

four suits during day and night high-altitude 

missions using Convair F-102 Delta Dagger 

interceptors. Ultimately, the squadron flew 

60 daytime sorties and 27 night sorties for a 

total of 124 hours and 55 minutes of flight 

time. Of these flights, 24 were flown with the 

suits unpressurized and 63 with the cockpit 

pressurization “dumped” so the suits would 

pressurize for at least part of the mission. In 

all, 24 sorties were flown with the A/P22S-2, 

19 with the A/P22S-3, 20 with the CSU-4/P, 

and 24 with the CSU-5/P. The pilots evaluated 

the suits in a readyroom environment that 

simulated 5-minute alerts lasting up to 

6.5 hours. The suits were also evaluated 

during cockpit alerts that lasted up to 2 hours, 

although the pilots did not wear gloves or 

helmets while in the cockpit. During these 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

280

Not much remains of the Air Force’s A/P22S-3 suit program, 

which was a slightly modified Goodrich-Navy Mark IV. Like 

many contemporary pressure suit gloves, the A/P22S-2 glove 

used leather on the palm to provide better feeling for the 

pilot. However, the glove fared poorly during Air Force coldweather evaluations.

Courtesy of the David Clark Company, Inc.

tests, the pilots rated each suit as satisfactory 

(S) or unsatisfactory (U) in 10 categories. The 

results are shown in the accompanying table; 

note that not every pilot rated every suit.

The evaluators noted that although suit 

donning was not an evaluation category, 

every pilot commented on the merits of the 

A/P22S-2, which could be donned unassisted 

in about 5 minutes. The pilots were also 

unanimous in praising the relative comfort of 

the A/P22S-2 and confirmed they could reach 

all of the controls and circuit breakers in the 

F-102, although it was not possible to see the 

left and right aft circuitbreaker panels.106

Given the excellent reputation of the 

Goodrich Mark IV suit in Navy service, it is 

interesting to note its rather dismal showing 

in the USAF evaluation. Part of this might be 

attributed to the suits not fitting properly at 

first, mostly because of a lack of experience 

from the suit technicians assigned to assist 

the pilots. The ratings tended to improve 

toward the end of the test after everybody 

had become more familiar with the suits, but 

the overall comfort and mobility ratings of 

the A/P22S-3 never matched that of the 

A/P22S-2. The pilots also did not appreciate 

the tight fit of the Navy suit and reported 

that it was difficult to don.

Because the pilots were used to wearing partial-pressure suits, the CSU-4/P fared well in 

the evaluation, with all of the pilots feeling it 

provided excellent comfort and mobility, even 

when pressurized at 55,000 feet. Nevertheless, 

the pilots felt that the suit was difficult to don, 

and they disliked that the suit would partially 

inflate when the wearer took a deep breath.

The CSU-5/P fared less well, primarily 

because the pilots felt it was too bulky (the 

result of the anti-exposure features integrated 

into the suit, rather than added over it as with 

the CSU-4/P). The evaluators noted that a 

near accident caused by the CSU-5/P, when 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

281

Table 5—Pilot Evaluations of Pressure Suits

A/P22S-2 A/P22S-3 CSU-4/P CSU-5/P

Category S U S U S U S U

Aerial Comfort 42 — 4 28 33 1 38 2

Ventilation 42 — 28 2 34 — 37 3

Mobility 42 — 3 29 34 — 40 —

Aircraft Control 42 — 23 9 34 — 40 —

Weapons System Control 42 — 19 9 31 3 39 1

Vision 42 — 32 — 33 1 40 —

Communication 42 — 33 — 34 — 40 —

Flight Safety 42 — 32 — 34 — 39 1

Ground Comfort 12 — — 12 12 — 3 9

Ground Mobility 12 — — 12 12 — 11 1

Total 360 — 171 101 291 5 327 17

Overall Rating 100 63 95

Source: Capt. Norman R. Smedes, 4750th Test Squadron, Tyndall AFB, FL, “Comparative Test of Aircrew Pressure Suits,” 

Project ADC/734AD/60-11, April 1, 1961.

a pilot on final approach lowered his landing 

gear and inadvertently caught the suit-toglove bladder hose on the throttle, shutting 

down the engine. Despite the precarious 

situation—1,000 feet above ground level, 

landing gear down, and only 220 knots—the 

pilot executed a successful air start and landed 

normally. The evaluators recommended the 

two partial-pressure suits be modified to cover 

the wrist hoses to prevent similar accidents in 

the future.107

Each suit was also tested at the All-Weather 

Climatic Laboratory at Eglin AFB, FL. This 

large facility is able to reproduce just about 

any imaginable weather condition, from 

well below zero to over 100 oF. The pilots 

entered the chamber equipped with only 

those items they would likely have after 

an ejection. For all tests, a flight surgeon 

observed the pilots to ensure they did not 

endanger themselves. The results of these 

tests were enlightening.108

The chamber was initially chilled to −5 oF 

and lowered 5 degrees per hour until it 

reached −25 oF. The wind, generated by a 

large fan, blew between 5 and 30 mph, and 

there was 4 feet of snow on the floor. The 

pilot wearing the A/P22S-2 suit had to leave 

after 2 hours and 30 minutes, complaining of 

a backache. The flight surgeon determined his 

backache was the result of a too-short suit, so 

the pilot donned a larger suit and returned to 

the chamber. He participated with the others 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

282

in building a snow shelter, and the pilot exited 

the chamber after 5 hours and 20 minutes, 

indicating he could have remained for an 

indefinite time. The pilot wearing the A/

P22S-3 suit also worked on the shelter, but 

he left the room after 2 hours and 15 minutes 

complaining of extremely cold hands and feet. 

His legs and knees were also cold, and his 

neck ring was frozen, preventing his helmet 

from rotating. He donned a second set of long 

underwear and returned to the chamber for 

an addition 2 hours and 40 minutes but still 

complained of being cold. For an hour, he 

wore a “combi suit” (a walk-around sleeping 

bag) and booties, which seemed to provide 

adequate warmth. The total time in the 

chamber was 4 hours and 55 minutes. 

The pilot wearing the CSU-4/P also wore a 

CWU-4/P anti-exposure suit and wool mittens 

from his survival kit. He left the chamber after 

3 hours and 20 minutes to relieve himself. 

Thirty minutes after returning to the chamber, 

he complained of extremely cold hands and 

feet. After donning a second set of long underwear and socks, he remained in the chamber 

for another 1 hour and 15 minutes. At the 

end of the test, after 5 hours and 5 minutes in 

the cold chamber, he was cold but otherwise 

mobile and healthy. 

The CSU-5/P was intended for water survivability. The pilot worked on the shelter and 

left the chamber after 4 hours and 10 minutes 

to relieve himself. He was in good condition 

except for coldness around the neck ring, 

caused by an improper helmet adjustment 

that allowed condensation from the faceplate 

to drain into the neck seal. After the helmet 

was adjusted, the pilot returned to the chamber for a total of 5 hours and 45 minutes. 

Cold-water tests were conducted in Lake 

Superior at Duluth, MN, where the air 

temperature varied from 10 to 21 oF, the 

water temperature was 33 oF, and wind blew 

from 10 to 18 knots. The subjects jumped 

into the lake from a 10-foot height wearing 

inflated LPU-2/P underarm life preservers. 

Each pilot was supposed to remain in the 

water for 15 minutes and then board a oneman life raft. Once again, a flight surgeon 

observed the pilots and took periodic oral 

temperature readings. 

The pilot wearing the A/P22S-2 suit remained 

in the water for 15 minutes, boarded the raft 

for 1 hour and 15 minutes, and then returned 

to the water for 15 minutes before terminating the test. He displayed no outward symptoms of exposure during or after the test but 

did complain of being cold. After leaving the 

water, he could walk with ease and his overall 

condition and demeanor appeared normal. 

The A/P22S-3 suit provided substantially similar results, not surprising given the premium 

the Navy placed on cold-water survival during 

its development. 

After only 1 minute in the water, the pilot 

wearing the CSU-4/P and CWU-4/P 

became extremely cold, and after 15 minutes, he had considerable difficulty boarding the raft because his legs were numb. He 

looked extremely cold and was shivering after 

15 minutes in the raft but indicated he was 

okay. Ten minutes later, he began to shiver 

violently and the flight surgeon terminated 

the test. The pilot’s legs were so numb he 

had to be helped from the raft, and his oral 

temperature had dropped to 94 oF. 

The CSU-5/P fared no better. After only a 

minute in the water, the pilot became very 

cold and climbed into the raft without significant difficulty. However, 10 minutes later, he 

became extremely cold and the flight surgeon 

terminated the test. The pilot’s oral temperature 

was 95 oF, but he was in relatively good condition compared to the subject in the CSU-4/P. 

The tests clearly showed the advantage of the 

full-pressure suits to protect the wearer against 

a harsh environment. Neither of the partialpressure suits was truly useable for more than 

an hour, even when equipped with an antiexposure cover. The two full-pressure suits, on 

the other hand, were demonstrably satisfactory 

for 5 to 6 hours, and possibly much longer. 

In the end, the evaluation recommended that 

if a pressure suit was to be made standard 

equipment, that the A/P22S-2 should be 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

283

selected. The report also contained a list of 

recommended modifications for the suit. The 

glare and reflection on the visor needed to be 

reduced, and the visor should be operable with 

one hand. In addition, the face-seal adjustment 

should be made independent of the earphone 

adjustment. On the suit itself, a small altimeter 

should be installed on the left thigh (it was, on 

some versions) and the suit controller should 

be made smaller. The flight surgeon also commented that each suit should come with two 

pairs of waffle-weave long underwear, as well 

as two pairs of cotton long underwear. The 

evaluators believed the F-102 should be modified with additional oxygen storage, a better 

ventilation unit, and a larger radarscope hood 

to accommodate the full-pressure suit helmet, 

and they also believed that each squadron 

should receive sufficient portable ventilation 

units and suit-tester units.109

The Air Force ultimately standardized on the 

David Clark A/P22S-2 full-pressure suit, and 

the Goodrich suit had a remarkably short 

USAF career. It could not be determined from 

available documentation exactly how many 

Goodrich suits were purchased or if they were 

ever issued to operational squadrons.

A/P22S-4 AND A/P22S-6—EVOLVING 

THE CONCEPT 

During January 1967, the USAF awarded 

David Clark Company a contract to modify 

the final A/P22S-2A (Mod 1) development 

suit into a prototype A/P22S-4 suit.110 The 

company developed the A/P22S-4 under the 

sponsorship of the 6570th Aerospace Medical 

Research Laboratory and Systems Engineering 

Group at Wight-Patterson AFB. 

The A/P22S-4 was the result of the ADC’s 

desires to improve the A/P22S-2. The first 

results were the A/P22S-2A and A/P22S-2A 

(Mod 1) suits, but, ultimately, they did not 

provide sufficient improvement to justify 

production. After the (Mod 1) effort, Joe 

Ruseckas and David Clark Company went 

back to basic research to determine the best 

method of improving the earlier suits. The 

advances developed during this research were 

incorporated into the Gemini and Dyna-Soar 

spacesuit efforts.111

Although pilots almost universally praised the 

A/P22S-2 for being easy to don and doff in 

comparison to other pressure suits, everybody 

realized it needed to be made easier if it was 

going to routinely meet the ADC’s 5-minute 

alert requirement. For the new suit, Ruseckas 

eliminated the U-entry of the A/P22S-2 and 

used a 37-inch pressure-sealing slide fastener 

that started at the front crotch and extended 

up the back parallel with the spine to a point 

12 inches below the neck ring. This dictated 

major revisions to the gas container and 

restraint coverall. The resulting rear-entry 

closure was similar in many respects to the 

opening developed for the David Clark 

Company Gemini spacesuits.

Moving the main entry to the back allowed 

the gas container to be shaped to better fit the 

chest, waist, and hips. The closer-fitting garment allowed easier movements by the wearer 

when pressurized. Molded flanges were incorporated for the wrist rings, making it easier to 

replace the hardware when needed. The upper 

torso on the A/P22S-2, except for the shoulders and parts of the chest, had been made 

from marquisette, which somewhat limited 

the mobility of the wearer. For the A/P22S-4, 

the upper torso was constructed entirely from 

Link-Net, which also allowed the layer to be 

adjusted to fit the wearer easier than the marquisette garment. Previously, the major deterrent from using a vertical rear-entry closure 

was sizing limitations around the waist and 

hips. The use of Link-Net largely solved these 

problems, and the restraint layer included 

adjustment laces on the forearms, waist, and 

each side of both legs. A takeup panel around 

the waist and hips extended up and around 

the main entry at the back and allowed adjustments without disrupting the slide fastener. 

This capability was a major advance over the 

A/P22S-2, for which torso adjustments were 

limited. By now, David Clark Company had 

figured out how to machine-make Link-Net, 

whereas previously, it had been entirely hand 

woven. It also had become obvious that the 

expected procurement of “thousands” of 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

284

pressure suits was hopelessly optimistic, so 

expanding the use of Link-Net was not a 

major cost driver.

The exterior cover was also changed 

significantly, mostly to conform to the 

rear entry and to improve mobility. Pocket 

locations, a seemingly trivial thing that was 

the source of many comments from pilots, 

were changed. The calf pockets were moved 

to the front of the leg to allow easier access 

by a seated pilot and the knife pocket was 

moved to the outside of the left thigh so as 

not to interfere with control-stick movements. 

There was also a cigarette pocket with pencil 

slots on the left sleeve. Most of these changes 

had been incorporated on the A/P22S-2A or 

(Mod 1) suits.112

An improved neck ring was similar to the 

one developed for the Gemini suit. On 

the A/P22S-2, it was necessary to position 

the helmet, seat it in the ring around the 

entire circumference, hold it in place, and 

then secure its locking ring. The improved 

neck ring replaced the locking balls with 

stainless steel latch dogs that held the helmet 

securing in place while the pilot rotated the 

locking ring.113

The gloves, always an object of criticism from 

the pilots, used softer leather but were otherwise unchanged. The full-pressure gloves had 

a dipped neoprene bladder covered by Nomex 

fabric, leather, and Link-Net. Straps on the 

back of the gloves provided for personal adjustments and palm restraints. The gloves attached 

to the suit at a nonrotating wrist disconnect.114

After production of the A/P22S-4 and 

A/P22S-6 suits began, David Clark Company 

developed a double latch for the lock on the 

glove disconnect that required a more intentional and deliberate action to unlock prior 

to glove removal. The new latches required 

that two fingers be used to depress them 

prior to sliding the lock into the open position and then rotating the disconnect ring to 

the unlocked position. This was in response 

to numerous incidents concerning the glove 

disconnect. This same wrist ring would be 

used on the A/P22S-4, A/P22S-6/6A, S901J, 

S1010, S1030, and S1031. It was not until the 

S1034 and S1035 that David Clark Company 

adopted a new ring using a rotating bearing. 

Interestingly, the rotating bearing idea, first 

seen on the A/P22S-2A (Mod 1), had been 

around for a while, and David Clark Company 

used it on special A/P22S-2 suits for the NASA 

lifting body program and the Gemini spacesuits and S901H special projects suit.115

The helmet consisted of a molded fiberglass 

shell, a cushion assembly that came in five 

sizes, a movable visor and independently movable sunshade, a neoprene-coated-fabric face 

barrier, an anti-suffocation valve, and a communications system. Oxygen was supplied 

through a rear helmet entry, via plumbing to 

the oral-nasal cavity. Exhaled gases were vented 

through a valve in the face barrier where they 

were routed with ventilating air back to the 

suit and eventually exhausted through the suit 

controller. Two different electrically heated 

acrylic visors were available: a laminated 

visor that used a wire grid, and a gold-coated 

conductive version. The aneroid-operated 

pressure-demand regulator delivered breathing 

oxygen to the breathing area of the helmet and 

automatically delivered makeup pressure to 

the suit in the event of pressure loss.

The helmet holddown assembly consisted 

of an endless-loop stainless steel cable that 

passed through metal guides on each side of 

the helmet disconnect ring. The cable also fed 

through nylon pulleys on the front and back 

of the suit. The front pulley was attached to 

an adjustable holddown latch used for helmet 

height adjustment.116

By mid 1966, when a service test quantity of 

A/P22S-4 suits became available, the ADC 

had largely abandoned using full-pressure 

suits, regardless of its drive to create the new 

suit. Despite an apparent lack of interest, on 

March 8, 1967, the ADC published Required 

Operational Capability (ROC) ADC-9-67 for 

a “Physiological Protection Garment.” After 

a rather brief evaluation, the ADC concluded 

that the A/P22S-4 suit did not satisfy the 

ROC requirements. 
237

It is possible the Royal Australian Air Force used 

A/P22S-4 suits in its F-111C fighter-bombers. The 

United States did not use pressure suits in its F-111, 

although some test flights did. Here is General Dynamics 

test pilot Val Prahl in an A/P22S-2 getting ready for a 

flight in an early F-111A. Note the U-shaped entry zipper 

and the leather knife pocket on the front of the left thigh.

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

286

The A/P22S-4 (S1023) was available in the 

standard eight sizes, based on nude height 

and weight. Seven sizes of restraint boots 

and four sizes of flocked boots were available. The standardized A/P22S-4 ensemble 

consisted of the HGK-19/P22S-4 helmet, 

orange CSK-8/P22S-4 coveralls, and HAK10/P22S-4 gloves.117 Apparently, David Clark 

Company produced only 17 A/P22S-4 suits 

for the USAF, significantly fewer than the 

number of A/P22S-6/6A suits that were fabricated. In addition, David Clark Company 

made a few sage-green A/P22S-4 suits for the 

Royal Australian Air Force, although exactly 

what airplane they were used in is unclear.118

Despite its considerable investment, much like 

the Navy, the Air Force quickly lost interest 

in the concept of an operational full-pressure 

suit. By 1965, the Strategic Air Command had 

decided that low-level bombing was the way 

of the future and began modifying the B-52 

for nap-of-earth (very low altitude) penetrations, essentially eliminating the need for pressure suits in strategic bombers. The ADC was 

seldom flying zoom intercepts, and its pilots 

did not like any of the pressure suits they 

had evaluated. As Jewel Melvin later noted, 

“Fighter pilots were accustomed to being relatively unencumbered to fly the airplane. They 

yearned for the scarf and goggles days and the 

suit took them in the opposite direction.”119

The TAC was too occupied with the buildup in Southeast Asia to be concerned with 

high-altitude flight. Ironically, besides the Air 

Force Flight Test Center and NASA, the major 

user of the A/P22S-2 was the Military Airlift 

Command (MAC), specifically, the 58th 

Weather Reconnaissance Squadron (WRS) 

that flew the General Dynamics WB-57F 

high-altitude reconnaissance aircraft. This, of 

course, ignores the other user of full-pressure 

suits: the CIA.

With the future of a standardized fullpressure suit now in doubt, on October 

25–26, 1967, the Aeronautical Systems 

Command held a conference with the 

MAC.120 The B-57F program began when 

the Air Force sought an aircraft with better 

performance than the RB-57D, which had 

been procured as an interim reconnaissance 

aircraft pending the development of the U-2. 

Because General Dynamics was responsible 

for contract maintenance on the RB-57Ds, 

the USAF asked the company to develop 

what became the RB-57F. The prototype 

made its first flight on June 23, 1963, using 

a new wing that spanned more than 122 

feet—some 14 feet more than the RB-57D 

and nearly double that of the original B-57B. 

General Dynamics replaced the Wright 

J65 turbojets with Pratt & Whitney TF33 

turbofans that provided twice the thrust. 

The empennage was also altered to provide 

sufficient stability and control at altitudes up 

to 80,000 feet. Eventually, General Dynamics 

modified 14 B-57 airframes into F-models.121

At some point, the USAF changed the 

RB-57F designation to WB-57F to reflect the 

weather-centric mission of the airplane.

The 58th WRS at Kirtland AFB, NM, received 

its first airplane in 1964 and deployed around 

the world to sample the upper atmosphere for 

evidence of nuclear weapons tests. Structural 

problems in 1972 forced the retirement of nine 

of the WB-57Fs, and the other five received 

new wings. Despite the major modifications 

to the wings, the 58th WRS retired its last 

WB-57F on July 1, 1974. NASA operated a 

single airplane (63-13501, NASA 925) from 

1968 until 1982 when it was retired to the 

Pima Air and Space Museum in Tucson, AZ. 

In 1972, NASA received one of the airplanes 

(63-13503, NASA 926) the 58th WRS was 

retiring and based it at Ellington Field near 

Houston. During 1974, NASA brought a 

second airplane (63-13298, NASA 928) out 

of retirement. These aircraft are still operational in 2010 and routinely conduct scientific 

research at altitudes in excess of 60,000 feet.122

During the summer of 1967, Military Airlift 

Command (MAC) pilots had conducted six 

WB-57F flights wearing S901J special projects 

suits for a total of almost 38 hours of flight 

time. In general, the pilots greatly preferred 

the J-suit to the normal A/P22S-2. In addition 

to these flights, pilots also spent about 30 flight 

hours using J-suit gloves with the standard 

A/P22S-2 suits. For instance, Maj. Theodore 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

287

Like the A/P22S-4 before it, the A/P22S-6 switched from 

the U-shaped entry zipper used on the A/P22S-2 to a rear 

entry. Previously, Joe Ruseckas and the designers at David 

Clark Company had found a vertical rear zipper created 

sizing problems around the waist and hips. Switching from 

the marquisette fabric used in the A/P22S-2 to Link-Net for 

the entire upper torso solved this problem. Here, the suit is 

pressurized to 3.5 psi, its normal operating pressure.

Courtesy of the David Clark Company, Inc.

A. Jenson, a command pilot with 5,784 total 

hours, including 552 in pressure suits, thought 

the J-suit was better fitting, although he found 

it was somewhat harder to don and doff. He 

believed the J-suit was more comfortable both 

pressurized and unpressurized, and that the 

soft foam helmet liner eliminated much of the 

head discomfort with the A/P22S-2. Helmet 

and glove ventilation were “markedly superior” 

in the J-suit, as was wrist mobility.123

At the time of the October 1967 pressure-suit 

conference, David Clark Company was under 

contract for the development and fabrication 

of the A/P22S-4 suit. Joe Ruseckas explained 

that the major differences between the 

A/P22S-4 then under development and 

the 901J special projects suit evaluated by 

MAC were the exterior cover, the oxygen 

system, the pressure-sealing zipper, and the 

range of sizes. One of the outcomes of the 

conference was a revision of the David 

Clark Company contract to reconfigure 

the A/P22S-4 suit per MAC requirements, 

instead of ADC requirements. 

The resulting suit was designated A/P22S-6 

(S1024). The suit was substantially similar 

to the A/P22S-4 (S1023) except for minor 

changes that made it more similar to the 

special projects suit (S901J). These changes 

included using a softer helmet liner, relocating 

the external communication leads to the 

right side of the helmet, incorporating a 

fire-resistant outer layer, adding a redundant 

pressure-sealing zipper, and deleting 

the built-in life preserver. The S-4 was 

manufactured in the standard 8-size heightweight tariff, while the S-6 was made to the 

old David Clark 12-size scheme, largely to 

satisfy the MAC.

During April 1968, the USAF awarded a contract to the David Clark Company to fabricate 

72 A/P22S-6 suits. The contract was later 

amended to provide 72 additional suits.124

During 1970, the WB-57F crews completed 

an operational suitability questionnaire for the 

A/P22S-6, and the results showed the crews 

preferred the A/P22S-6 to other pressure suits 

(mostly the A/P22S-2) they had used. Since 
236

The U.S. Air Force does not use pressure suits in its 

McDonnell Douglas (Boeing) F-15 Eagle fighters. However, 

the Israeli Defense Forces used the A/P22S-6 full-pressure 

suit in some of its aircraft for undetermined reasons.

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

289 One concern with the pressure suit is the relative clearance 

of the pilot’s shoulders with the sides of the airplane during 

ejection. These photos show the relative roominess of the rear 

cockpit (left) of NASA’s WB-57F aircraft compared to the 

front. Each of these pilots is wearing an A/P22S-6 pressure 

suit. Note that the back-seater has his clear visor down while 

his tinted visor is still up. 

NASA

most had never used a special projects suit, it 

is unknown if they would have preferred the 

S901 suit.125

The standardized A/P22S-6 ensemble 

consisted of the HGK-19/P22S-4 helmet, 

CSK-9/P22S-6 coveralls, and HAK-10/

P22S-4 gloves. Note that only the coveralls 

were different from the A/P22S-4. The last 

production quantity of A/P22S-6 outfits 

included shipping containers that were 30 by 

12 by 15 inches, approximately 4 inches 

longer than the containers used by all previous 

suits. This additional length was requested by 

the MAC crewmembers to facilitate carrying 

leather flight boots in the container.126 David 

Clark Company also provided 16 A/P22S-6 

suits to the Israeli Defense Forces for use in its 

Peace Jack F-4E(S) and F-15A/Bs.

Despite having talked about pressure suits for 

a decade, by 1970 the USAF was still struggling with integrating their use into the cockpit of the few aircraft that still needed them. 

In particular, the General Dynamics WB-57F, 

Lockheed F-104 Starfighter, and Convair 

F-106 Delta Dart had cockpits that seemed 

too small to permit the efficient use of fullpressure suits, despite the fact that the aircraft 

had accommodated the suits for years. During 

1970, the USAF conducted an evaluation to 

determine the effects of wearing the 

A/P22S-2 and A/P22S-6 in these aircraft. This 

included evaluating each suit in the cockpit, 

both unpressurized and pressurized, as well as 

conducting anthropometric measurements to 

study the mobility and reach of crewmembers 

in the suits.127

The concern can be illustrated by noting that 

the width between canopy sills in the front 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

290

cockpit of the F-104 was only 26.5 inches, 

while the width in the F-106 was 27.7 inches 

and the B-57 was 29.9 inches. An extralarge A/P22S-6, when inflated, measured 

27.4 inches across the shoulders, while a 

medium suit measured 24.85 inches. This 

made a successful ejection from an F-104 

unlikely and cast doubt on the F-106 and 

B-57. For instance, an extra-large A/P22S-2 

would clear the canopy sills in the front 

position of a B-57 when an ejection seat was 

raised under a 1-G situation on the ground. 

But when the suit was inflated to 3 psi, the 

elbows frequently got stuck under the canopy 

sill, which during a real ejection at 15-G, 

would have resulted in tearing the suit or 

serious injury to the pilot. The back seats of 

all the aircraft were somewhat wider than 

the front seat and presented less of an issue, 

particularly in the B-57.128

The evaluation concluded that a pilot sitting 

in the front seat of the F-104 and F-106 could

see and reach all of the instruments and controls with little difficulty. The pilot’s knees and

legs were in a good position for ejection, but 

the helmet was too far from the headrest and 

the arms and shoulders would likely contact 

the canopy sills. The evaluators stressed that 

prior to their first flight wearing a pressure suit

in a specific aircraft type, each crewmember 

and an observer should carefully determine if 

the crewmember could reach all the controls 

and assume a safe ejection position. This 

should be done with the suit unpressurized 

and pressurized. The report concluded that 

the pilot “should use the outfit operationally in the aircraft only if he and a qualified 

observer or observers are confident that the 

above tasks and ejection from the aircraft can 

be performed in a satisfactory manner.”129

During July 1970, the San Antonio Air 

Materiel Area at Kelly AFB, TX called a 

conference to review improvements to be 

incorporated into a small production batch 

of full-pressure suits being procured in 

1971. For the most part, the changes to the 

A/P22S-6A were incremental improvements 

over the A/P22S-6. The most significant was 

the addition of a urine-collection system to 

allow crewmembers to relieve themselves in 

flight without opening the suit. The urinecollection system, for men only, consisted 

of an inner hose connected to an external 

catheter, a release valve, and an external hose 

 attached to a storage bag mounted on the 

aircraft. The other major change was a station-

 ary hold-down cable guide located near the 

top of the pressure-sealing slide fastener that 

replaced the back helmet hold-down pulley. 

To improve reliability and maintainability, 

and to increase comfort, the neoprene-flocked 

 boot and nylon-restraint boot were replaced 

with a neoprene coated oxford nylon boot 

in four sizes. In addition, the face seal was 

modified for additional comfort, the torque 

for the helmet disconnect was reduced, and 

the leg adjustment cords were modified to 

prevent breakage. Minor changes included 

a redesigned oxygen valve, the addition of a 

pencil pocket that attached with Velcro, elbow 

patches, different thigh pockets, a new helmet liner cushion, and a revised microphone 

bracket. The most obvious change was that 

the outer cover was changed from two-ply 

sage-green, herringbone-weave Nomex to oneply international-orange, high-temperature, 

nylon-twill cloth, and all zippers were changed 

from dark oxide to bright brass.130

The standardized A/P22S-6A (S1024A and, 

later, S1024B) High Altitude Flying Outfit 

ensemble included the HGK-19/P22S-4 

helmet, CSK-9A/P22S-6 coveralls, and 

HAK-10/P22S-4 gloves. Note that only the 

coverall was different from the A/P2S-4 or 

A/P22S-6. The A/P22S-6A consisted of 

(from the wearer out) long underwear, comfort 

liner with integrated vent ducts and antiblock 

devices, gas container, restraint layer, and the 

exterior cover. The comfort liner was made of 

smooth nylon fabric that facilitated donning 

and doffing, and it reduced friction with the 

gas container. A series of snap fasteners and 

fastener tape integrated the comfort liner with 

the gas container. The vent duct assembly was 

a network of channels that brought cooling air 

to the head, torso, hands, and feet. Stainless 

steel springs in the channels kept them from 

collapsing as the suit moved. The vent inlet was 

located on the front-left side of the suit torso.131
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

291

The A/P22S-6A introduced a variety of changes to earlier 

suits that improved comfort and serviceability. One major 

change was a stationary holddown-cable guide located 

near the top of the pressure-sealing slide fastener that 

replaced the back helmet holddown pulley in the helmet 

holddown system. A pulley was still used in front to 

provide the necessary adjustments.

Courtesy of the David Clark Company, Inc.

The neoprene-coated nylon gas container 

extended over most of the torso, arms, and 

legs but not the hands or feet. Combination 

bladder-restraint boots were attached to the 

gas container at the calves. A rear-entry 

pressure-sealing closure extended from the 

crotch to the upper mid-back. Sizing panels, 

or cords, on the restraint assembly at the 

waist, chest, upper and lower arms, legs, and 

back allowed personal adjustments. The pressure controller was an aneroid-operated device 

that controlled suit pressure and acted as the 

outlet valve to discharge vent air. The controller was calibrated to maintain suit pressure at 

175 ± 7 mm Hg (3.5 psi, 35,000 feet).

The helmet disconnect ring incorporated a 

sealed bearing that permitted helmet and head 

rotation. Vent air passed through a neck-ring 

ventilation plenum and entered the helmet 

interior through two slots in the disconnect 

ring. The helmet holddown consisted of a 

stainless steel cable that passed through a 

nylon pulley on the front of the suit and a 

metal cable guide on each side of neck ring. 

The cable was secured at the rear of the suit 

via a retainer assembly that locked the ends 

of the cable.

Ultimately, David Clark Company produced 

80 A/P22S-6A suits. The A/P22S-6 and 

A/P22S-6A were used in the General 

Dynamics WB-57F, Convair F-102 Delta 

Dagger, Lockheed NF-104A Starfighter, 

Convair F-106 Delta Dart, North American 

XB-70A Valkyrie, and McDonnell Douglas 

F-4 Phantom II.132

In addition, at least one USAF F-15A 

received the necessary modifications to use 

the A/P22S-6 full-pressure suit. Beginning 

on January 16, 1975, three Air Force pilots 

and a modified F-15A (72-119) made an 

assault on the world-class time-to-climb 

records for aircraft powered by jet engines. 
236

Streak Eagle pilots (from left) Maj. Willard R. “Mac” 

MacFarlane, Maj. Roger J. Smith, and Maj. David 

W. Peterson pose in front of their modified McDonnell 

Douglas F-15 Eagle. Smith and Peterson wore David 

Clark A/P22S-6 full-pressure suit on their high-altitude 

record-setting flights.

National Museum of the United States Air Force Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

293

The three pilots—Maj. Roger J. Smith, 

Maj. Willard R. “Mac” MacFarlane, and 

Maj. David W. Peterson—were all members 

of the F-15 Joint Test Force at Edwards. 

Pete Garrison, a McDonnell Douglas test pilot, 

was instrumental in the development of the 

flight profiles used for the record flights. 

On April 1, 1974, the Air Force awarded 

McDonnell Douglas a $2.1 million dollar 

contract to modify an early F-15A to 

support the record attempt. All non-mission 

critical systems were deleted, including the 

flap and speed brake actuators, cannon and 

ammunition-handling equipment, radar 

and fire-control systems, noncritical cockpit 

displays and radios, one of the generators, the 

utility hydraulic system, and, of course, the 

50 pounds of paint (hence the Streak Eagle

name). Significant additions included a revised 

oxygen system, support equipment for the 

A/P22S-6, extra batteries, a pitot boom with 

alpha and beta vanes, an over-the-shoulder 

video camera, a battery-powered radio, 

sensitive accelerometers, a standby attitude 

gyro, a large very-high frequency (VHF) 

antenna under the canopy behind the pilot, 

and a special “hold-down” device in place of 

the tail hook. 

All of this effort resulted in saving approximately 1,800 pounds. When weighed 

in preparation for a 30,000 meter run 

(on test flight no. 37), 72-0119 weighed 

36,799 pounds. For the record attempts, 

the aircraft was physically held down to the 

runway while the pilot applied full power. 

The record runs were accomplished at Grand 

Forks AFB, ND, where the cold atmospheric 

conditions were ideal. Six different record 

flights were flown, and margins of between 

15 and 33 percent were achieved over the 

previous records. Peterson and Smith used 

A/P22S-6 suits for all flights 15,000 meters 

and higher.

A highly modified MiG-25 (E-266) later 

recaptured several of the higher altitude 

records and set one to 35,000 meters 

(nearly 22 miles). All of the records have 

since been broken by the P-42 prototype for 

the Sukhoi Su-27. There was consideration 

given to further modifying Streak Eagle, 

including using more powerful production 

engines, and making another attempt, but 

this never materialized. Streak Eagle was 

turned over to the Air Force Museum where 

it is currently in storage.133

By 1978, the A/P22S-6 suits were reaching the end of their service lives. The USAF 

intended to replace the suit with the new 

High Altitude Protective Outfit, but funds 

were not available to complete development. 

In addition, the need for full-pressure suits 

in the regular Air Force had seemingly disappeared. A limited number of the suits had 

their service lives extended to support the 

NASA WB-57F effort and other small needs 

from NASA and USAF programs.134

BOYLE'S LAW SUIT

During the late 1960s, a team at the Air Force 

School of Aerospace Medicine at Brooks AFB 

developed a different type of pressure suit as 

part of Project 7164 “Aerospace Protective 

Technology.” The team included Lt. Col. 

Frederick R. Ritzinger, Maj. Jefferson C. Davis, 

and MSgt. Henry B. Whitmore with major 

contributions by Maj. Joseph Boyle III.135

Streak Eagle takes off at Grand Forks AFB on one of its 

record-setting flights. Roger Smith took the airplane to 

98,425 feet in 207.80 seconds, although the record has since 

been broken by a modified MiG-25.

National Archives College Park Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

294

Table 6—Streak Eagle Time to Climb Records

Altitude 

(meters)

Altitude 

(feet) Date Pilot Old record (seconds)

Goal 

(seconds)

Actual 

(seconds)

3,000 9,843 Jan 16, 1975 Smith 34.50 27.00 27.57

6,000 19,685 Jan 16, 1975 Macfarlane 48.80 38.60 39.33

9,000 29,527 Jan 16, 1975 Macfarlane 61.70 47.90 48.86

12,000 39,370 Jan 16, 1975 Macfarlane 77.10 58.00 59.38

15,000 49,212 Jan 16, 1975 Peterson 114.50 73.70 77.02

20,000 65,616 Jan 19, 1975 Smith 169.80 126.10 122.94

25,000 82,020 Jan 26, 1975 Peterson 192.60 163.70 161.02

30,000 98,425 Feb 01, 1975 Smith 243.90 206.90 207.80

The researchers believed that, “None of the 

operational pressure suits in the USAF inventory is compatible with present or future 

USAF mission requirements. Present pressure 

suits are bulky and complicated. All current 

partial or full-pressure suits are uncomfortable 

during long-term unpressurized wear. These 

inadequacies have led to the rejection of pressure suits by high altitude fighter pilots and 

to the astronauts removing their pressure suits 

during extended orbital flights. They have also 

led to promotion of a so-called shirt-sleeve 

environment, even for military missions in 

which cabin depressurization may be encountered at any time by enemy action.”136 These 

criticisms may have been extreme since there 

were other, perfectly valid reasons for some of 

the actions cited, but there was no question 

that pressure suits were complicated and generally uncomfortable devices.

The A/P22S-6 suits have had long lives with the NASA 

WB-57F program at Ellington Field, TX. Unlike their sexier 

silver cousins at the Flight Research Center, the WB-57F suits 

are standard international orange with orange gloves and 

black boots. There was some consideration to using S1035 

suits from the Space Shuttle after that program ended in 

2011, but this would have required a major reconfiguration 

of either the suits or the airplanes and was rejected as 

uneconomical. Note the portable air-conditioner connected 

to the suit. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

295

The Boyle’s Law Suit consisted of a loosely 

fitted restraint coverall made from a permeable fabric with multiple collapsible closed 

cells filled with a predetermined amount of 

gas. A neck seal provided closure between the 

suit and helmet. The essential theory was that 

as the ambient pressure outside the suit fell, 

the gas in the closed cells expanded, applying 

mechanical counter-pressure to the skin. The 

cells were independent and a leak in one did 

not seriously degrade the operation of the suit. 

On the ground, the cells occupied about a 

quarter of the space between the body and the 

restraint coverall, leaving a half-inch void that 

provided comfort for the wearer. Even at a 

pressure altitude of 27,000 feet, the expanding 

cells did not completely fill this void, leaving 

the suit somewhat loose. At higher altitudes, 

the restraint coverall forced the cell’s expansion against the skin. The individual cells were 

tailored to specific parts of the body to ensure 

that the suit did not “bulk up” too much as 

the cells expanded.

Chamber tests up to 70,000 feet were generally successful, although despite the tailoring 

of individual cells, the suit did not provide 

uniform pressure on all parts of the body. The 

chamber tests, some of which lasted an hour, 

showed this was of little consequence and was 

a reasonable price to pay for reduced bulk.137

Although an interesting concept, there was 

little reason to switch from the existing pressure suits and the concept languished. 

PHAFO—THE STILLBORN 

HIGH-ALTITUDE FLYING OUTFIT

In 1974, the USAF initiated the High 

Altitude Flying Outfit (HAFO) program 

to develop a pressure suit suitable for use in 

the new McDonnell Douglas F-15 Eagle. 

The F-15 had its origin in the mid-1960s, 

when the aircraft industry was invited to 

study requirements for an advanced tactical 

fighter to replace the McDonnell Douglas F-4 

Phantom II as the primary fighter in service 

with the USAF. The aircraft needed to be 

capable of establishing air superiority against 

all projected threats in the post-1975 period. 

Without compromising the primary air-to-air 

combat role, the aircraft was to be capable of 

performing a secondary air-to-ground mission 

and needed a top speed in excess of Mach 2.5 

at altitudes above 60,000 feet. The Tactical 

Air Command, the intended user of the F-15, 

believed that a new full-pressure suit was 

needed for the air superiority mission.

The USAF circulated a draft Required 

Operational Capability (ROC) document 

among the user commands for comment. 

Eventually, the combined efforts of the 

Aeronautical Systems Division, the School 

of Aviation Medicine, and the Air Logistics 

Command apparently convinced the TAC 

that its desired capabilities were too far in 

advance of the state of the art. The ROC 

was never formalized, and the installation 

of full-pressure-suit systems was eliminated 

from production USAF F-15s.138

On the other hand, at least some of the 

F-15A/Bs delivered to Israel had the capability 

to use pressure suits, and David Clark 

Company supplied 18 A/P22S-6 suits to the 

Israeli Defense Forces (IDF). In addition, the 

USAF had loaned the IDF some earlier A/

P22S-2 suits for use in its McDonnell Douglas 

F-4 Phantom IIs, most likely the modified 

Peace Jack variants operated as reconnaissance 

aircraft. The IDF returned the suits to David 

Clark Company for depot-level maintenance a 

couple of times but did not replace them when 

they reached the end of their service lives.139

The HAFO program did not progress further 

until June 1976, when the pressure suit depot 

notified the Aeronautical Systems Division 

that the A/P22S-6 full-pressure suits were 

going through their last permissible overhaul. 

This would carry the inventory through 

1983, at which time there would be no 

more pressure suits available unless new A/

P22S-6 suits were purchased or a new suit 

was developed. In response, the Aeronautical 

Systems Division decided to purchase new 

state-of-the-art suits based on the experience 

gained from the A/P22S series, the special 

projects suits used by the U-2 and SR-71, and 

the various NASA manned space programs. 

In reaching this decision, the Aeronautical 

Systems Division noted that although previous 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

296

suits had provided the required physiological 

protection, “the users have not been the most 

satisfied group of people in the USAF.”140

The USAF wanted an altitude suit that also 

protected against water immersion, chemical and biological agents, penetration and 

impacts, windblast, open flames, and explosive 

decompression. In addition, the ensemble 

needed to provide protection against reflections and glare; allow the pilot to eat, drink, 

and pass urine; and be compatible with the 

standard USAF G-suit. The requirements 

indicated the suit should not balloon (grow 

in size) more than the A/P22S-2 and have 

communication performance better than the 

A/P22S-6. The suit needed to withstand an 

overpressure of 7.0 psi and fit the 5th to 95th 

percentile of pilots. Perhaps the most interesting requirement was to “be esthetically appealing to crewmembers.”141

The USAF awarded contracts to ILC Dover 

(F33657-77-C-0667) and David Clark 

Company (F33657-77-C-0668) for design 

studies and the fabrication of Prototype 

High-Altitude Flying Outfit (PHAFO) suits. 

ILC Dover proposed to develop a full-pressure 

suit while David Clark Company proposed 

a partial-pressure suit.

The suit delivered by ILC included was a 

5.0-psi full-pressure garment complete with 

convoluted joints and a continuous cable 

restraint system at the shoulders based on 

the Apollo suit design. The garment used a 

single-layer butyl-coated Kevlar-Nomex gas 

container, and the pilot donned it through an 

extruded, two-part, “tobacco pouch” pressuresealing slide fastener at the waist. The top and 

bottom of the suit were separable to allow 

mix-and-match sizing. A lower-torso buckle 

assembly, upper-torso buckle assembly, and a 

torso-adjust strap created a block-and-tackle 

system extending from the shoulder to the 

lower abdominal area. This allowed the torso 

to be foreshortened, modifying the contour 

and relieving some of the load on the slide 

fastener. The neck ring included a bearing to 

allow head rotation, and a neck seal separated 

the helmet from the suit. A suit-mounted 

demand regulator provided breathing oxygen 

directly to the helmet. Exhaled breathing air 

was exhausted into the suit through an expansion valve in the neck seal. The detachable 

gloves used a neoprene-dipped nylon pressureretention layer that was similar to the NASA 

Apollo gloves. A heavier neoprene-dipped 

nylon-restraint layer covered all portions 

except the fingers. A gimbal ring attached at 

the wrist provided mobility. Standard flight 

boots covered the feet.142

The ILC suit included a Kevlar-graphitefiberglass, hard-shell, semi-conformal helmet 

that had a movable visor and integral communications equipment. The helmet used a 

ring-bearing disconnect to attach to the suit. 

The helmet included an anti-suffocation valve 

that opened with each breath to supply ambient air if the oxygen supply was cut off. The 

material was chemical- and biological-agent 

resistant. Flat patterning of the joints at the 

neck, elbows, hips, knees, and ankles contoured the suit to the cockpit and provided 

decent mobility. A standard G-suit was worn 

under the pressure suit, and a cooling vest 

was available. An anti-exposure garment was 

worn under the pressure suit, as was a urinecollection system.143

David Clark Company delivered its PHAFO 

on September 13, 1978. The suit consisted 

of a coverall, communications carrier and 

oxygen mask, nonconformal helmet, and 

a retainer assembly with parachute harness 

and floatation gear. The suit was a modular 

ensemble that could be used with optional 

sunshades or polarized lead zirconium titanate 

(PLZT) flashblindness-protection devices, 

chemical/biological filters, a G-suit, or a 

urine-collection system.144 Standard flight 

boots provided adequate foot protection for 

limited periods, and MG-1 gloves (as used 

on the MC-3A and MC-4) were modified 

to work with the new suit.145

The David Clark Company design philosophy 

was to create a self-donned ensemble that 

required substantially fewer special support 

considerations than previous pressure suits. 

The coverall assembly consisted of upper and 
297

The David Clark Company PHAFO was evaluated by 

Jack Bassick, during water tests in a local swimming 

pool during 1979. The suit consisted of a coverall, nonconformal helmet, and a retainer assembly with parachute 

harness and floatation gear. The exterior of the suit was 

made of high-temperature FyproTM material and the 

gold color was a compromise between its fire retarding 

capabilities and the need to reflect some solar radiation 

to keep the suit cool.

Courtesy of the David Clark Company, Inc.

lower modules that could be interchanged 

between certain sizes to increase the fitting 

flexibility within the standard eight-size tariff. 

Designers selected a double-walled bladder 

configuration that eliminated the need for 

a pressure-sealing closure and simplified the 

design. A review of historical data showed 

that the pressure zipper was one of the most 

maintenance- (and failure-) intensive items 

on most pressure suits. The effectiveness of 

the double-walled bladder had been shown 

on the CSU-4/P.146

The designers considered the ease of donning 

the suit while wearing the standard G-suit. 

David Clark Company investigated several 

configurations but rejected most as overly 

complicated or too difficult. In the end, it 

selected a concept similar to the A/P22S-2. 

With the upper and lower modules connected 

to each other, the need for pilots to start a separating fastener or make gas connections was 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

298

The anatomy of a modern 

partial-pressure suit. The 

David Clark Company 

Prototype High Altitude 

Flying Outfit (PHAFO) 

consisted of several modular 

components that made 

the suit easy to fabricate 

and service.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 6: Air Force Full-Pressure Suits

299

eliminated. The modules could be separated 

by undoing some laces and a few screws, but 

this was normally performed by technicians, 

not pilots. The bladders used urethane-coated 

nylon, and a butyl layer provided chemical 

and biological protection. Link-Net was used 

extensively in the shoulders, arms, and legs 

to increase mobility. An integrated parachute 

harness and dual flotation cells were worn 

over the outer layer of the suit. A nonconformal, dome-type helmet with a two-ply visor 

and hinge-mounted sunshade was provided. 

The pressure controls were generally similar 

to those used on late-model A/P22S-6A fullpressure suits.147

The exterior of the suit was made of hightemperature FyproTM material.148 Fypro is 

produced through a process in which DuPont 

Nomex is saturated with an aqueous solution and put in an autoclave to increase 

its oxygen index under heat and pressure. 

The fire-retardant characteristics of Fypro 

are directly related to its level of processing 

and the resultant color of the material. The 

darker the color, the more fire retarding it is. 

Green Nomex becomes dark brown Fypro 

while white Nomex becomes dark gold. The 

color of a pressure suit is an interesting, and 

emotional, quandary. The search-and-rescue 

people want orange in snow or white in jungle 

areas. Physiologists want a color that keeps 

the aviator cool. Pilots want something that 

looks good. The gold color selected for the 

PHAFO was a compromise between its fireretarding capabilities and the need to reflect 

solar radiation to keep the suit cool.149

Both of the prototype HAFO suits weighed 

more than the 37.4-pound A/P22S-6; the 

ILC Dover suit weighed 39.6 pounds, 

and the David Clark Company suit 

weighed 39.4 pounds (45.3 pounds if all 

the optional chemical filters and PLZT 

goggles were included).150

Each contractor tested its suit against the 

USAF requirements prior to delivery. The 

ILC Dover suit did not meet the required 

donning time, primarily because of the entry 

pressure fastener and the time required to 

operate it. In addition, the anti-suffocation 

valve was too small, and the suit did not float 

well. The David Clark Company suit showed 

distortion in the visor; donning required 

the use of a mirror (or extensive practice) 

although it could be completed within the 

allocated time; and the suit ballooned more 

than the specification allowed. The Aeronautical Systems Division conducted extensive 

tests on both suits after they were delivered 

to Wright-Patterson AFB. On April 10–11, 

1979, a USAF assessment team met to discuss 

the test results with the group concluding 

neither prototype offered sufficient improvement over the A/P22S-6 suit to warrant 

further development.151

Given the relatively limited need for pressure 

suits within the regular Air Force (i.e., not the 

“special projects” U-2 and SR-71), the USAF 

concluded that the existing A/P22S series of 

pressure suits could be overhauled and refurbished to meet the requirements.
7
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

301

7: Special Project Suits

The Air Force designations for pressure 

suits never made much sense to anybody 

outside the industry and possibly, not much 

to those even directly involved. The Central 

Intelligence Agency (CIA) never worried 

much about designations and simply used 

the David Clark Company model numbers 

when referring to pressure suits. Eventually 

the Air Force came to the same conclusion. 

Unfortunately, the David Clark model 

numbers are only marginally better. The 

ubiquitous “Sxxx” designations are used by 

the full range of David Clark Company 

personal-protection equipment, so pressuresuit model numbers are scattered among other 

numbers for “Air Police Boots” and “Valve, 

Heart.” In addition, the company has frequently assigned multiple model numbers to 

the same basic configuration or, conversely, 

used the same model number for several 

different configurations. It is one of the 

consequences of a small company fabricating a handmade, custom-fitted product 

for a trusting customer. Despite the sometimes apparent randomness as viewed from 

the outside, it all seems to work just fine 

and has served the Air Force, CIA, and 

NASA well for over 50 years.

S901 AND S970—SUITS FOR OXCART

The early 1950s were a period of rapid technological advance for United States military 

aviation. In February 1953, Chance-Vought 

delivered the last piston-powered fighter 

(a Vought F4U Corsair). Three months later, 

North American delivered the YF-100 Super 

Sabre, the first fighter capable of supersonic 

speeds in level flight. There were five publicly 

known air arms: the Air Force, the Army, 

the Coast Guard, the Marine Corps, and the 

Navy. There was soon to be a sixth, unknown 

to all but a few.

In March 1953, the CIA issued a specification for a new reconnaissance aircraft capable 

of an altitude of 70,000 feet and a range of 

1,750 miles. The agency believed that the high 

operational ceiling would enable the aircraft 

to penetrate Soviet airspace at subsonic speeds 

with relative immunity from interception. 

The requirement eventually resulted in the 

development of the Lockheed U-2, possibly 

the most famous secret aircraft ever built. The 

U-2 became operational in June 1956 and 

remained an invaluable intelligence-gathering 

asset for almost 4 years, until May 1, 1960, 

when Francis Gary Powers was shot down 

A line of Lockheed A-12s at 

the test facility on Groom 

Lake, NV. The second 

airplane in line is the only 

two-seat A-12. At this point 

in their careers, the aircraft 

were in their natural 

titanium finish except for 

the composite chines and the 

rudders on some aircraft. 

Courtesy of Lockheed 

Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

302

near Sverdlovsk, Soviet Union. However, 

even as the CIA tested and began using the 

U-2 over the Soviet Union, it was obvious 

that a faster and higher flying aircraft would 

be needed to stay ahead of the burgeoning 

surface-to-air missile threat. 

In 1956, the CIA appointed Richard M. 

Bissell, Jr. (1910–1994), who had been 

program manager for the U-2, to oversee the 

development of an advanced reconnaissance 

aircraft. Bissell realized the development 

and production of such an aircraft would be 

exceedingly expensive, and there was a great 

deal of skepticism about whether the project 

could succeed at all. To secure the necessary 

funds, Bissell needed the support of the most 

believable experts he could find. Accordingly, 

Bissell put together a panel chaired by Edwin 

M. Land (1909–1991), a respected American 

scientist and cofounder of the Polaroid 

Corporation. Between 1957 and 1959, this 

panel met six times, usually in Land’s office 

in Cambridge, MA. 

The requirements for the new reconnaissance 

airplane were quietly floated to a small number of aircraft manufacturers. At the Lockheed

Skunk Works, Kelly Johnson began designing an aircraft that would cruise at Mach 3.0 

and altitudes above 90,000 feet. On July 23, 

1958, he presented this concept to Land’s 

advisory panel, which expressed interest in the 

approach. Two months later, after reviewing 

a proposal from Convair and yet another 

Lockheed design, the Land panel concluded 

it would be feasible to build an aircraft whose 

speed and altitude would make radar tracking difficult and interception impossible. 

The panel’s findings had precisely the impact 

Bissell wanted. Based on Land’s recommendation, President Dwight D. Eisenhower 

approved $100 million to develop and manufacture 12 aircraft. 

On August 20, 1959 (1 month before the 

first flight of the North American X-15 

research airplane) Lockheed and Convair 

submitted proposals to a joint Air Force and 

CIA selection committee. The two aircraft 

were similar in performance and the Lockheed 

design was selected based mainly on cost. 

Ironically, at the end of August 1959, the 

fastest air-breathing aircraft ever built was 

given the code name Oxcart. 

According to the specifications, Oxcart was 

to fly at Mach 3.2 (2,375 mph: 2,064 knots, 

or 3,484 feet per second, making it somewhat 

faster than a 0.30 rifle bullet), have a range of 

4,120 nautical miles, and reach altitudes of 

 84,500 to 97,500 feet. The new aircraft would 

be five times faster than the U-2 and would fly 

almost 3 miles higher. By mid-January 1960, 

various changes had evolved the Lockheed 

design number to A-12, the 12th iteration of 

what Kelly Johnson had named Archangel. 

Afterward, Johnson noted in the Archangel

project log: “We have no performance margins 

left; so this project, instead of being 10 times 

as hard as anything we have done, is 12 times 

as hard. This matches the design number and 

is obviously right.”1

 Johnson had a wry sense 

of humor. 

The original Lockheed proposal included 

using a version of the U-2 partial-pressure 

suit. However, heat radiated from the 400 oF 

windshields would drive cockpit temperatures 

above 100 oF during Mach 3 cruise. Even 

Johnson admitted this, “would require that 

the pilot be provided with some sort of a cooling and ventilation garment.”2

 Fortunately, 

now Brig. Gen. Donald D. Flickinger was 

providing an independent assessment of pilot 

protection for Richard Bissell. After his service 

on the U-2 program, Flickinger was the CIA’s 

“go-to guy” when it came to physiology for 

much of the early Blackbird era. Jack Bates 

and Bruce Bassett were the USAF program 

physiologists, defining the requirements and 

qualifications, as well as monitoring the flightcrews. Because of the prolonged time at high 

altitude and the extreme heat in the cockpit, 

Flickinger believed the pilots of the A-12 

needed a full-pressure suit similar to the one 

being developed for the X-15 program. 

As Lockheed developed the A-12, it became 

necessary to involve other contractors to 

supply specialized parts. Lockheed selected 

Firewel to build the oxygen system and 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

303

Left: The parts that made up an S901 helmet are laid-out for 

display. Note how the microphone is attached to the face seal. 

Below: David Clark Company used a mockup of the 

A-12 parachute pack to test with the S901 full-pressure 

suit interface. 

Courtesy of the David Clark Company, Inc.

supply the protective garment for the pilots. 

Firewel subcontracted to the David Clark 

Company for a pressure suit, although at the 

time it was not clear exactly what form it 

would take. In early 1960, Lockheed held a 

predevelopment conference attended by Joe 

Ruseckas from David Clark Company and a 

representative from Firewel. Having seen how 

uncomfortable the partial-pressure suit was in 

the U-2, and based on advice from Flickinger, 

the CIA wanted a full-pressure suit for the 

A-12. Kelly Johnson would have none of that, 

believing the suit was too heavy and his airplane did not need one. After a heated discussion, Ruseckas got up to leave, but the CIA 

representative calmed everybody down and 

made it clear that a full-pressure suit had just 

become a firm requirement. Somewhat later, 

the CIA contracted directly with David Clark 

Company for the pressure suits (although 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

304

The S901 series of suit evolved separately, but simultaneously, 

from the A/P22S series of suits David Clark Company was 

making for the “normal” Air Force. Nevertheless, there was 

a bleed over of ideas between the projects since the same few 

designers were working both. The S901 series was generally 

a more form-fitting suit and the aluminized HT-1 exterior 

covers made them look more futuristic than the sage-green or 

orange covers used by the other suits. Note the white boots. 

This is the prototype S901 suit with an A-12 ejection seat in 

April 1961.

Courtesy of the David Clark Company, Inc.

Firewel still was the prime contractor for the 

oxygen system, suit pressure controllers, and 

breathing regulators). On Oxcart, everybody 

had a codename, and David Clark Company’s 

was “Northeast Manufacturing.”3

The pressure suit needed to provide altitude 

protection and thermal insulation during 

cruise, and it needed to protect the pilot 

against heat and windblast during ejection. 

However, the last requirement was not really 

as bad as one would expect. Although Oxcart

cruised at a high Mach number, because of the 

extreme altitude, this corresponded to only 

175 knots equivalent airspeed. In fact, the 

maximum equivalent airspeed, at any altitude, 

was only 400 knots. Windblast and deceleration effects at these velocities were relatively 

low, and aerodynamic heating of the pilot 

during ejection was not a serious problem. At 

100,000 feet altitude and Mach 3.2, deceleration of an ejection seat from cruise speed to 

terminal velocity would take 52 seconds. The 

initial 10 seconds of this deceleration was the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

305

Joe Ruseckas in the third S901 (S901-3) suit in July 1962. 

This shows the U-entry feature that Ruseckas believed 

would make the suit easier to don and doff. The zipper 

starts on one shoulder, runs down and across the back, 

then up onto the other shoulder. This type of closure would 

be adapted to the A/P22S-2, but most David Clark fullpressure suits would later use a simpler rear-entry zipper. 

The aluminized HT-1 exterior cover has been removed 

for these photos.

Courtesy of the David Clark Company, Inc.

critical period for aerodynamic heating. After 

that, the ejected pilot had slowed to approximately Mach 2.3, with a corresponding reduction in temperature.4

The CIA also asked Flickinger to draw up 

the criteria for pilot selection, with advice 

from Kelly Johnson and CIA Headquarters. 

Pilots had to be qualified in the latest high 

performance fighters and be emotionally 

stable and well-motivated. They were to be 

between 25 and 40 years of age, and the size 

of the A-12 cockpit dictated they be under 

6 feet tall and less than 175 pounds. Air Force 

personnel files were screened for possible 

candidates who were called for interviews 

without disclosing for what project they were 

being considered. The requisite psychological 

assessments and physical examinations 

eliminated many candidates, but eventually a 

list of 16 potential pilots was assembled. This 

group underwent further security and medical 

scrutiny by the CIA. Those who remained 

were approached to take employment with the 

CIA on a highly classified project involving 

a very advanced aircraft. In November 1961, 

commitments were obtained from five pilots, 

and arrangements were made with the Air 

Force to effect appropriate transfers and 

assignments to cover their training and to lay 

the basis for their transition from military to 

civilian status. Compensation and insurance 

arrangements were similar to those for the 

U-2 pilots.

The CIA ordered the first Oxcart suit on 

March 7, 1960, tailored for Capt. Harry 

Collins, the guinea pig who tested the S901 

before “production” suits were ordered. Since 

the participant names were closely held, 

David Clark Company referred to Collins as 

Subject 1, roughly the same routine it had 

used during the original U-2 program. In 

addition to altitude chamber and thermal 

tests, Collins made several parachute jumps 

to verify the suit worked outside the airplane. 

Joe Ruseckas generally flew in the C-130 with 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

306

Collins to make certain the suit was ready for 

the jump. The suit, sans occupant, was also 

tested on the North Base rocket sled track at 

Edwards AFB.5

The original S901 “Flying Outfit, Fullpressure, High Altitude, Multi-Layer” suit 

for Oxcart included an outer layer made from 

aluminized HT-1 (an aromatic polyamide 

fiber created by DuPont for use at high temperatures and later named Nomex), a doublelatch Protection, Inc. neck ring, and a single 

pressure-sealing slide fastener.6 All Blackbird 

suits used a U-entry until the S970 and S901J, 

which used rear entry. A biomedical instrumentation pad was located on the back. 

Eventually, Collins and the physiologists were 

satisfied and the USAF ordered a second suit 

on June 28, 1962. This one was made for 

Louis W. “Lou” Schalk, Jr. (Subject 2), the 

Lockheed test pilot who became the first to fly 

the A-12. This S901A was similar to the S901 

except it used a single-latch neck ring instead 

of the original double-latch neck ring. The 

suit used a lot of insulation under the aluminized HT-1 cover, but Schalk felt the suit was 

too bulky, so later suits (including Schalk’s 

second) deleted most of the insulation.7

The S901B featured a biomedical fitting 

instead of a pad and was custom made for 

Subject 3, but nobody remembers who that 

was or why the suit was made. Like the 

original S901, this suit used a double-latch 

neck ring.8 The suit apparently never flew.

The S901C used a single-latch neck ring and 

included a double slide fastener: one regular 

and one pressure-sealing. This suit was custom 

made for Ed Markum, another USAF parachutist who helped qualify the suits.9

The S901D switched from Protection, Inc. 

neck rings to Air-Lock neck rings and featured 

revised communications equipment and forearm disconnects. The first two suits were custom made for William C. “Bill” Park, Jr., and 

Lou Schalk (who, for unremembered reasons, 

became Subject 6 for this suit).10

The S901E was a heavily revised suit that 

evolved from the earlier models and was 

the first to be called a “Pilots Protective 

Assembly.” The restraint layer switched from 

marquisette to Link-Net with a sage-green 

oxford-nylon-restraint cover. Sizing panels 

were added to the ends of the sleeves and 

legs for personal-fitting adjustments. The 

exterior cover continued to use aluminized 

HT-1 fabric (Nomex) and now included an 

integral flotation bladder. New altimeter and 

bioinstrumentation ports were used. A watch 

pocket was added to the left glove, thigh and 

calf pockets were added to the legs, and a 

knife pocket was added to the inside of the 

left thigh. Joe Ruseckas added a hidden inner 

pocket to the inside of the right leg to hide 

contingency money and papers in the event 

the pilot was forced to abandon the airplane. 

The visor used a gold coating as the conductor for the electrical defogging system, and 

pilots frequently complained of being able 

to “count the pores” on their faces because 

David Clark fabricated the S901C for Ed Markum, another 

parachutist that helped qualify the suit. Harry Collins, the 

original parachutist, is standing next to Markum holding 

binoculars, on December 19, 1963. Note the parachute is 

still attached to Markum.

Courtesy of the David Clark Company, Inc.
307

The Lockheed YF-12A was undoubtedly the most 

advanced interceptor ever built by the United States 

and was capable of Mach 3 at altitudes exceeding 

80,000 feet. The aircraft was equipped with a longrange radar and three Hughes AIM-47 Falcon missiles 

with nuclear warheads. Weapons systems tests proved 

remarkably successful, and after the YF-12 program was 

cancelled, the radar and missiles formed the basis of the 

system used on the Grumman F-14 Tomcat.

National Museum of the United States 

Air Force Collection
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

309

Before the YF-12 interceptor program was cancelled, the 

Air Force used one of the aircraft to set several Fédération 

Aéronautique Internationale (FAI) Class C-1 Group 3 

(turbojet-powered landplanes) records on May 1, 1965. In 

one of these, Maj. Walter F. Daniel (pilot) and Capt. James 

P. Cooney flew 1,688 mph over a 1,000-kilometer closed 

course. All of the pilots wore S901F suits during the flights. 

At right, Daniel is congratulated by Clarence R. “Kelly” 

Johnson, the chief designer at the Lockheed Skunk Works.

National Archives College Park Collection

layer, and a restraint cover. The aluminized 

HT-1 exterior cover completely covered the 

suit to provide protection against windblast 

and heat. The exterior coverall was donned 

separately using a center-front slide fastener 

and included an integral floatation system. 

The helmet used a face seal that isolated the 

breathing space from the suit. The plexiglass 

visor included an electrically conductive gold 

coating for defogging, and a dual pneumatic 

seal inflated automatically when it was lowered. The gloves used a neoprene bladder with 

a Link-Net restraint layer and featured leather 

palm and finger surfaces. The back of the fingers was an aluminized oxford-nylon material, 

and the knuckles were Helenca (a fabric with 

a one-way stretch). The remainder of the glove 

was aluminized HT-1 fabric. The gloves were 

attached to the suit sleeves by a mechanical 

metal ring that did not use bearings.15

David Clark Company fabricated the suit in 

12 sizes: small, medium, large, and extra large, 

with short, regular, and long versions of each. 

The YF-12A cockpits were somewhat larger 

than the A-12, and the S910F suits fit pilots 

ranging from 125 to 224 pounds and from 

63 inches to 76 inches tall. Laces were provided to adjust the length of the legs and 

sleeves. Gloves were available in 12 sizes, the 

boots were available in 7 sizes, and the helmet 

was supplied with the 3 sizes of crown pads. 

The aircraft normally provided ventilation 

air for the suit, which was only pressurized in 

an emergency. If the cabin altitude exceeded 

35,000 feet, the primary suit-pressure control 

system maintained a pressure of 178 ±7 mm 

Hg (between 34,500 and 36,000 feet) or, if 

that should fail, 167 ± 7 mm Hg (35,000 to 

37,000 feet) with the secondary system. A 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

310

Lockheed test pilot William 

C. “Bill” Park, Jr. in the 

S970-5-3 suit without an 

exterior cover. The rearentry zipper extended from 

the shoulder blades to the 

front of the crotch. Note the 

extensive use of Link-Net 

for the restraint layer, 

similar to the X-15 suits.

Courtesy of the David Clark 

Company, Inc.

press-to-test button for each system pressurized the suit to 2.25 psi. A back kit contained 

the emergency oxygen supply, and an antisuffocation feature was built into the left-hand 

helmet bearing that deflated the visor seal 

about 50 seconds after oxygen depletion. A 

DN-500-U portable vent kit and a DN-500-I 

portable oxygen kit could be connected to the 

suit for ground use.16

The suit operating manual contained a caution: “Under no circumstances will the suit 

be worn in flight with the main entry slide 

fastener unlocked or the relief slide fastener 

open. Glove disconnects must be locked and 

sealed. The helmet must be locked to the suit 

disconnect ring with the visor in the closed 

and locked position.”17

The S901G was generally similar to the S901F 

but was custom fitted instead of coming in 

12 standard sizes. Because they were custom 

fitted, the adjustment laces on the arms and 

legs were omitted. This suit also appears to 

have been oriented toward the YF-12A program, probably for a pilot that did not fit well 

into the 12 standard sizes. 

The S901H was the primary production suit 

for Oxcart, but it was a major departure 

from previous S901 suits. The majority of the 

hardware (neck and wrist rings, pressurization 

controls, etc.) was similar to the S901F, but 

the basic softgoods (gas container and restraint 

layer) came from the S971, which was an 

A/P22S-2 suit. Nevertheless, Joe Ruseckas and 

the designers at David Clark Company made 

some major changes for this application.18

Instead of the U-entry used on the A/P22S-2 

and all previous Oxcart suits, the S901H 

used a pressure-sealing zipper installed vertically in a straight line from a point on the 

upper back approximately between the shoulder blades, down and under the buttocks, 

and terminating in the front approximately 

waist high. The vertical zipper allowed a 

better-fitting garment, and an expanded 

use of Link-Net over the entire torso greatly 

improved mobility.19 The Link-Net leg design 

had adjustable cords on the inner and outer 

seams in place of laces on the calf. Vent ducts 

extended to each extremity, and the vent system was attached to the inner liner instead of 

the gas container. The rear helmet holddown 

pulley was fixed instead of being adjustable. 

This suit came in the standard 12 sizes.20

The first S901Hs, produced in 1965, used an 

outer layer made of aluminized HT-1 with 

no separate exterior cover. However, Oxcart

pilots had long complained the aluminized 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

311

The A-12s were eventually painted overall black, like their 

later SR-71 cousins. The A-12 proved to be a remarkable 

aircraft and was the fastest of the Lockheed Blackbirds. 

Political considerations, and the fact that the Air Force 

SR-71 carried a more diverse reconnaissance suite, led to 

the early retirement of the A-12. 

Courtesy of Lockheed Martin Aeronautics

suit created undesirable reflections around the 

cockpit. In response, David Clark Company 

developed a white Dacron outer layer for later 

S901Hs, but the Dacron was not fireproof so 

it was backed with HT-1 fabric, adding some 

bulk to the suit.21

A late modification for the S901H added a 

urine-collection system. This consisted of a 

pair of underwear drawers with pile fastener 

tape fitted to a circular opening in front, a 

latex-rubber external catheter that mated 

with the fastener tape on the drawers, and a 

hose-and-valve arrangement that connected 

the duct to an external repository. This same 

arrangement would be used on the S901J, 

A/P22S-6A, and most later suit designs.22

David Clark Company lists the S970 as a 

modification of the S901G, but it seems to 

have more in common with the S901H. It 

used a rear-entry zipper instead of a U-entry 

and the outer layer was aluminized HT-1 with 

an integrated floatation garment. No separate 

exterior coverall was required.23

The first A-12, known as Article 121 (USAF 

serial number 60-6924), was assembled and 

checked out in Burbank during January and 

February 1962. Since it could not be flown 

to Groom Lake, the aircraft was partially 

disassembled and put on a special trailer. 

Lockheed made appropriate arrangements with 

the police and local officials to safely transport 

the aircraft without disclosing exactly what 

was in the odd-shaped container. The entire 

fuselage, minus wings, departed Burbank on 

February 26, 1962, and arrived at the test 

location 2 days later.24

On April 26, 1962, Lockheed test pilot Lou 

Schalk took the A-12 for an unofficial first 

flight, flying less than 2 miles at an altitude 

of about 20 feet. This unexpected event 

occurred during a high-speed taxi run when 

the aircraft began a series of oscillations as 

the nose wheel lifted off the ground. Schalk 

immediately added power and lifted the 

aircraft into the air, regaining control. Once 

he managed to stop the oscillations, Schalk set 

the A-12 safely back onto the lakebed. Kelly 

Johnson noted that this “...was obviously a 

day for the A-12, in that 2 × 6 = 12.”25 The 

“official” first flight took place on April 30, 

1962, witnessed by a number of CIA and 

USAF representatives. With Schalk again at 

the controls, Article 121 took off at 170 knots 

and climbed to 30,000 feet, achieving a top 

speed of 340 knots during the 59-minute 

flight. On May 2, 1962, during its second test 

flight, the aircraft broke the sound barrier, 

reaching Mach 1.1 for a few minutes.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

312

Initially, the A-12 had a design top speed of 

Mach 3.2 (2,064 knots), a maximum altitude 

of 87,000 feet, and a range of 3,600 nautical miles. This was later raised to Mach 3.29 

and 90,000 feet. Nevertheless, the airplanes 

were initially restricted to Mach 2.35, at first 

because of the limited thrust of the interim 

Pratt & Whitney J75 engines (the definitive 

Pratt & Whitney J58s were not yet ready), 

then because of inlet issues and unacceptable 

engine airstart capabilities.

The first Oxcart accident, in Article 123 

(60-6926), took place on May 24, 1963, 

near Wendover, UT. CIA project pilot 

Ken Collins remembered: 

I was flying a subsonic J58 engine test 

flight at 25,000 feet altitude with Jack 

Weeks as the F-101 chase pilot. In my 

turn back to base, we ran into heavy 

clouds and rain. Trying to get above the 

weather, I climbed up to 30,000 feet, 

but was still in the heavy clouds. I waved 

Weeks off, because of the dense clouds 

and turbulence since The F-101 was 

prone to pitch-ups in slow flight. All 

cockpit instrument readings appeared to 

be normal, but the flight controls were 

slow responding. Rechecking all the 

instruments, I saw the altimeter beginning to rapidly ‘wind’ down, as did the 

airspeed indicator. Having no visual references in the clouds, I was uncertain of 

my true altitude and airspeed; the flight 

instruments were unreliable. Within seconds, the airspeed decreased to 102 KIAS. 

Then the A-12 stalled and pitched up and 

over into an unrecoverable flat inverted 

spin. Having no positive idea of my 

real altitude, I choose to eject from the 

inverted aircraft.26

Because this had been a “low and slow” evaluation flight, Collins was not wearing his S901 

pressure suit, but instead he wore a normal 

flight suit and helmet. Fortunately, Collins 

survived the ejection little the worse for the 

experience. The subsequent investigation 

determined that a flaw in the pitot system was 

the root cause of the accident. Jack Bassick 

and Bob Banks at David Clark Company 

remember that many low-and-slow flights 

were made without pressure suits, as were 

most flights in the two-seat Titanium Goose

trainer (60-6927). Collins remembers that 

“after the trainer check out, the object was to 

become familiar and comfortable in the pressure suit, therefore; the pressure suits were 

always used.” But he hastens to add, “nothing 

is ‘always.’ ”27

Based on a series of modifications, the 

allowable speed of the A-12 was raised to 

Mach 2.8 in July 1964 and to Mach 3.0 in 

March 1965. It was not until August 1965 

when electronic inlet controls began to 

be installed that operational aircraft were 

cleared to Mach 3.2. Aircraft also needed 

structural modifications to fuselage station 

715 (the wing join) before being allowed to 

exceed Mach 3.0. Between the first flight in 

April 1962 and March 24, 1965, the fleet 

accumulated only 15 hours above Mach 3, 

all by Lockheed flight-test aircraft. The first 

operational aircraft flown by a project pilot to 

exceed Mach 3.0 was Article 128 (60-6931) 

on March 25, 1965, but it would be several 

months before this became routine.28

During the fall of 1965, the Oxcart fleet 

began to carefully venture up to Mach 3.0, 

with an average of 1.28 hours at Mach 3.0 

per aircraft to validate operational systems. In 

January 1966, flight activity was substantially 

curtailed during the investigation of the 

December 28, 1965 accident of Article 126 

(60-6929). This aircraft crashed shortly after 

takeoff because Lockheed wired the yaw and 

pitch gyros in the stability-augmentation 

system incorrectly, and the aircraft became 

uncontrollable. The project pilot, Mele 

Vojvodich, was wearing his S901 suit and 

ejected successfully.29

By the spring of 1966, the operational aircraft 

and project pilots again began to fly, spending an average of 45 minutes per sortie at 

Mach 3.0. In a September 1966 document, 

the CIA reported that the fleet of 10 airplanes 

(7 operational A-12s, the two-seat Titanium 

Goose trainer, and 2 flight-test aircraft) had 
313

The M-21/D-21 combination demonstrated the 

significant difficulties of separating two vehicles at 

high Mach numbers and were intended to provide an 

unpiloted reconnaissance capability over China and 

the Soviet Union. The M-21 was a two-man version 

of the CIA A-12 reconnaissance aircraft and carried 

the D-21 drone to its Mach 3 launch conditions.

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

314

accumulated 2,078 flights for a total time 

of 3,186 hours and 39 minutes. Of these, 

485 flights had been at or above Mach 3 for 

a total of 244 hours and 39 minutes; 264 of 

these flights were by operational aircraft, the 

remainder by flight-test aircraft. Pilots had 

used the S901 pressure suits on 1,480 of the 

2,078 flights. During this period, no sorties 

were cancelled or aborted because of issues 

with the S901 suits, although two missions 

were cancelled due to cockpit-pressurizationsystem problems.30

By 1968, one Mach 3.3 flight had lasted 

3.5 hours, and the longest Oxcart flight 

was 7.6 hours (with aerial refueling). There 

had been 2,670 total flights, of which 1,751 

used S901 pressure suits. Between August 26, 

1965, and December 31, 1967, a period that 

included operational Black Shield flights 

over Vietnam, the pressure suit worked on 

692 sorties of 693 attempted wearing the suit. 

Pilots wearing S901 suits had experienced 

three ejections. Bill Park and Mele Vojvodich 

survived, but Walt Ray was killed when a seat 

malfunction precluded man-seat separation 

after ejection.31

When originally conceived, the primary mission for Oxcart was to overfly the Soviet 

Union. After Francis Gary Powers and his 

U-2 were shot down on May 1, 1960, the 

rules changed. One of the many concessions 

made by President Eisenhower for the release 

of Powers was the immediate cessation of all 

manned overflights. The word “manned” was 

carefully stipulated because of the possibilities 

envisioned for future Corona reconnaissance 

satellites. However, since the satellites were 

still several years away from operations, the 

CIA decided that a drone also fell outside the 

“manned” category.

The drone had to be simple, relatively lightweight, and able to fly Mach 3 at 90,000 feet, 

and it had to have a low radar cross section 

and be compatible with systems and techniques already developed for Oxcart. Because 

of the complexities of turbojet power and its 

associated intakes, the J58 was quickly discarded in favor of a Marquardt RJ43 ramjet 

borrowed from the IM-99 BOMARC surfaceto-air missile. Since ramjet engines do not 

function at low speeds, a modified A-12 was 

selected as a platform that would carry the 

drone to Mach 3 and then release it. The CIA 

called the drone Tagboard, and it was originally known within Skunk Works as the Q-12. 

As work progressed, however, it was given the 

D-21 designation (D for daughter), while its 

two-seat Blackbird carrier aircraft was called 

the M-21 (M for mother). 

The two M-21s (Article 134, 60-6940 and 

Article 135, 60-6941) were purpose built, 

not modified, A-12s, although there were 

remarkably few differences. A dorsal-mounted 

pylon carried the D-21, but aerodynamic 

considerations resulted in the pylon being 

shorter than Kelly Johnson desired. This 

dictated that the M-21 “push over” during 

launch, instead of flying straight and level as 

originally intended, a concession later regretted. In addition, the aft fuselage of the M-21 

was strengthened around the pylon attach 

points. Unlike the original A-12s, the M-21 

carried a back-seater known as the Launch 

Control Officer (LCO) who used a periscope 

to monitor the drone. Only 6 inches of clearance existed between the wingtips of the D-21 

and the top of the M-21’s vertical stabilizers.

The first captive-carry flight, with Lockheed 

test pilot Bill Park in the front cockpit and 

no LCO, took place on December 22, 1964, 

coincidently the same day that the first 

SR-71 made its maiden flight. The basic 

flight-test program lasted just over a year. 

The first successful launch occurred on 

March 5, 1966, with the D-21 (503) 

having only 25 percent of its design fuel 

load. The second D-21 (506) launch carried 

a 50 percent fuel load on April 27, and the 

first launch with a fully fueled D-21 (505) 

occurred on June 16. The full fuel load 

allowed the D-21 to fly nearly 1,600 miles 

while making eight programmed turns and 

maneuvers. The flight-test effort then stood 

down to digest what had been learned.

The mated combination was not as straightforward as it might appear. The weight of the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

315

Top, right: An M-21 approaching a tanker to refuel before 

launching the D-21. There were only 6 inches of clearance 

between the D-21 wingtips and the top of the M-21’s 

vertical stabilizers.

Bottom, right: The M-21/D-21 program ended tragically 

on July 30, 1966, when the D-21 impacted the M-21 after 

launch. Bill Park and Ray Torrick successfully ejected, but 

Torrick drowned when his pressure suit took on water after he 

landed in the ocean. The project was immediately cancelled, 

although Lockheed modified the surviving drones to be 

launched from B-52 motherships. Four operational D-21B 

missions over China took place under the codename of SEnior

Bowl between November 9, 1969, and March 20, 1971, to 

photograph the Lop Nor nuclear test site.

Courtesy of Lockheed Martin Aeronautics

D-21 significantly slowed the acceleration of 

the Blackbird. To be at the correct speed and 

altitude over the designated Pt. Mugu launch 

area, the M-21 had to begin its speed run 

over Albuquerque, NM. Once the Marquardt 

ramjet in the D-21 was running at full power, 

the pilot flew the M-21 in a 0.9-G downward 

arc to assist in separation. Fuel reserves were 

minimal when the M-21 reached the launch 

point, and an in-flight refueling was made 

immediately after the drone was launched (or 

immediately after the decision was made not 

to launch it).

Bill Park did not believe that a sustained 

0.9-G downward arc could be maintained 

under the pressure of an operational mission. 

To determine how critical it was to maintain 

exactly 0.9-G, a scheduled July 30, 1966, 

full-fuel launch (using Article 135 and 504) 

attempted separation in level flight. For the 

first 2–3 seconds of the drone launch, everything went normally. Unfortunately, the 

drone was not able to penetrate the Mach 3 

shock wave coming off the mothership. The 

D-21 just cleared the M-21’s rudders when 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

316

it encountered the shock wave, bounced off, 

rolled 45 degrees to the left, and impacted the 

Blackbird where the forward fuselage attached 

to the wing root. The M-21 tumbled out of 

control and into the Pacific. Bill Park and 

Ray Torrick successfully ejected, but Torrick 

drowned when his pressure suit took on 

water. Some reports attribute this to Torrick 

prematurely opening his visor, but informed 

sources have stated that the buoyancy of the 

David Clark suits makes this unlikely. Others have speculated that shrapnel from the 

wreckage tore his suit as he ejected. Regardless, Kelly Johnson and the CIA promptly 

cancelled Tagboard. 

This accident provided the impetus for David 

Clark Company to add an automatic flotationinflation device to later special projects suits. 

David Clark Company also redesigned the 

suit’s integrated flotation garment to provide 

higher floatation and a more vertical orientation in the water. In addition, the company 

designed a new, easier-to-board life raft, which 

was approved by the program in June 1967. 

Training was given to the project pilots using 

the new raft in Lake Mead during June 1967.32

Almost a decade elapsed between when the 

concept for the Oxcart aircraft was first 

examined and the first A-12 being operationally deployed. Then, after only 29 operational 

missions, the most advanced air-breathing aircraft ever built was retired. The abandonment 

of the Oxcart did not result from any particular shortcomings of the aircraft but lay in 

fiscal pressures and competition between the 

reconnaissance programs of the CIA and the 

Air Force. Oxcart was replaced by the heavier 

and somewhat slower SR-71.

All A-12 aircraft at Groom Lake and the forward operating base at Kadena AB, Okinawa, 

Japan, were ordered flown to the Lockheed 

facility in Palmdale. Unfortunately, on June 4, 

1968, Article 129 (60-6932) was lost during a 

functional checkflight out of Kadena to test a 

replacement engine. The aircraft disappeared 

520 miles east of Manila; search and rescue 

crews never found a trace of the plane or its 

pilot, Jack W. Weeks. Several days later, the 

last two aircraft from Kadena joined the other 

six aircraft in Palmdale for storage. Article 131 

(60-6937) made the last A-12 flight from the 

Nevada test site to Palmdale on June 21, 1968.

The dozen single-seat A-12s had accumulated 

slightly over 3,727 hours of flight time during 

2,189 flights. The lone two-seat trainer added 

another 1,076 hours in 614 flights. Of the 

13 aircraft, 5 single-seat A-12s were written 

off in accidents, but no A-12s were lost to 

enemy action.

In 1972, the CIA floated a proposal to revive 

Oxcart for surveillance flights over North 

Vietnam. When the Oxcart program was 

cancelled, the surviving A-12s had been placed 

in flyable storage in Palmdale, along with a 

complete “regeneration” package that included 

the operating procedures, mission directives, 

checklists, and names of qualified personnel. 

The package included sufficient spare parts 

and aerospace ground equipment to reconstitute five operational aircraft and support them 

for 90 days. During this time, the CIA would 

award the appropriate contracts to provide 

longer-term support.33

The CIA intended to conduct flight training 

at Beale AFB so the effort could share the 

airspace already allocated to SR-71 operations. The agency expected to have one pilot 

and one aircraft operationally capable within 

45 days of the order to proceed. Operational 

missions would be flown from Kadena and 

require 200–250 personnel. The only 

major modification was to switch to SR-71 

ejection seats and S901J pressure suits 

since the Oxcart seat was “unsatisfactory” 

and the Oxcart pressure suits were no 

longer available.34

The revived Oxcart never happened and the 

aircraft remained in storage until they were 

dispersed to museums in 1991.

S-100—HYBRID SUIT FOR THE 

ORIGINAL U-2

In early 1970, officials at Lockheed asked 

Joe Ruseckas if he could improve the 
317

The David Clark Company S-100 developed for the U-2C 

aircraft that were still in service during the 1970s. Although 

it had been demonstrated that the A/P22S-2 family of suits 

would work in the early U-2s, the Air Force was reluctant to 

invest in the necessary modifications. This led Joe Ruseckas 

to adopt an A/P22S-6 full-pressure helmet to a capstan 

partial-pressure suit, replacing the USAF MA-2 style helmet 

that was no longer supportable. 

Courtesy of the David Clark Company, Inc.

partial-pressure suit used by the first-generation U-2s. Although flight tests had concluded 

that a full-pressure suit would physically fit 

in the cockpit, the USAF was hesitant to 

make the required changes to the airplane. 

Ruseckas agreed that a better partial-pressure 

suit could be created. Contrary to popular 

reports, the resultant S-100 suit was not so 

much a modification of the MC-3A partialpressure suit as an entirely new suit based on 

the MC-3A design and hardware. Ruseckas 

decided that much of the discomfort experienced by the pilots on long flights was more 

the result of the MC-2 helmet, rather than 

the suit itself. Therefore, he decided to mate a 

full-pressure helmet from the A/P22S-6 with a 

new partial-pressure suit. Because of the neck 

ring required for the full-pressure helmet, the 

David Clark Company softgoods expert, Ed 

Dubois, developed patterns for a rear-entry 

suit instead of the shoulder entry of most 

partial-pressure suits. The novel integration of 

the A/P22S-6 helmet with a partial-pressure 
318

The radical concept behind the S-100 partial-pressure suit 

was the use of a full-pressure helmet. The novel integration 

of the A/P22S-6 helmet with a partial-pressure suit provided 

considerable improvement in early-model U-2 pilot comfort 

and mobility along with a commensurate reduction in stress 

and fatigue. Like many full-pressure helmets, the S-100 

helmet used a face seal to contain the oral-nasal breathing 

compartment, while the suit used a neck seal to contain the 

breathing bladder inner wall. The use of a conventional 

full-pressure suit neck-ring and bearing greatly improved 

pressurized mobility. 

Courtesy of the David Clark Company, Inc.

suit provided considerable improvement in 

pilot comfort and mobility along with a commensurate reduction in stress and fatigue.35

Ruseckas took the prototype S-100 to 

Tyndall AFB where USAF physiological 

training officer Paul Roberts ran the altitude 

chamber. Ruseckas did a chamber check to 

60,000 feet, followed by Roberts. The new 

helmet demonstrably improved comfort, and 

after further qualification tests, David Clark 

Company started fabricating S-100 suits for 

the USAF and NASA (the CIA having long 

departed from the scene).36 Note the S-100 

model-number uses a dash (unlike most David 

Clark Company model numbers) and is far 

outside the normal model number sequence.

The helmet was essentially identical to the 

one used on the A/P22S-6 and consisted of a 
319

Except for the neck seal and full-pressure helmet, the S-100 

looked much like a partial-pressure suit. Large capstans ran 

up the legs and arms, and there were lace-adjustment panels 

on the chest and shoulders. Note the NASA U-2C (ER-1) 

behind NASA pilot Jim Barnes in the background. The 

S-100 was used by the Air Force and NASA until they each 

retired their early-model U-2s

NASA

fiberglass shell fitted with a movable visor and 

independent sunshade, an oxygen system, an 

anti-suffocation valve, a takeup adjustment 

mechanism, cushion assembly, and communications. The molded fiberglass shell contained 

channels that distributed vent air around the 

head. A spray bar around the inner edge of the 

visor opening delivered breathing oxygen and 

kept the visor from fogging. A face seal separated the helmet breathing space from the rest 

of the helmet. The spring-loaded exhalation 

valve passed exhaled air from the breathing 

space to the pressure-suit breathing-bladder 

assembly. An anti-suffocation valve was 

mounted on the left side of the helmet and 

opened to the atmosphere if the oxygen supply was depleted. A drinking and feeding port 

was located at the lower-right front of the helmet. The helmet used two different electrically 

heated visors, one with a gold coating and one 

with a laminated grid for defogging.37

The suit consisted of a coverall with a restraint 

assembly, a capstan assembly, and a breathing 
320

Much like the MC-3 and MC-4 before it, the S-100 featured 

an exterior cover that could be worn to protect it against 

snagging on items in the cockpit. The exterior cover also had 

extra pockets and large Velcro pads on the thighs to mount 

checklists and other materials.

NASA

bladder that was worn directly over a set of 

long underwear. The capstan and breathingbladder assemblies provided sufficient protection up to 80,000 feet. Interdigitizing tapes 

around the capstans extended down the back 

and along the sides of the arms and legs to 

provide counter-pressure. Slide fasteners 

located in the center of the back, wrists, and 

ankles facilitated donning, and laces along the 

arms, legs, chest, and back allowed individual 

size adjustments. Adjustable breaklines at the 

waist and groin allowed the pressure bladders to crease at those locations to facilitate 

standing and sitting. The breathing bladder 

wrapped completely around the torso and 

incorporated a neck seal on the inner wall 

and a neck ring on the outer wall. A perforated inner liner at the front and back of the 

bladder permitted vent air to flow around the 

wearer. The capstans and pressure bladders 

were fabricated from coated nylon cloth. 

The breathing bladder used the standard fullpressure suit dual-system controller, however 

the controller was rescheduled to maintain 

155 mm Hg (38,000 feet) instead of the 
321

NASA used the U-2C as an Earth resources aircraft at the 

Ames Research Center in California. Here the airplane is 

posed with a variety of payloads it could carry during its 

research missions. 

NASA

175 ± 7 mm Hg (35,000 feet) protection of 

the contemporary Blackbird full-pressure suits. 

The S-100 helmet included a single-system 

breathing regulator from the A/P22S-6. 

The suit and gloves were available in the 

standard 12 sizes, and there were 4 sizes 

of helmet cushions.

The partial-pressure gloves were made from 

Nomex with soft black suede leather palms, 

and an elastic cuff. Lacings on the back of the 

hand allowed personal adjustments. A slide 

fastener, extending from the top of the cuff to 

the palm, allowed donning. A bladder assembly extended from the wrist to the top of the 

fingernails on the backside of the hand. 

The separate Nomex exterior cover included 

slide fasteners in the front, and at the wrists, 

and at the lower legs and were available in 

several colors, including sage green and international orange. Snap tabs at the waist and 

wrists allowed limited adjustments. The cover 

had a pocket on each lower leg, a leather-lined 

knife pocket on the inside of the right leg, and 

a pocket with pencil accommodations on the 

upper right sleeve.38
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

322

Operational U-2C flights began using the 

S-100 in early 1972, and Air Force and NASA 

pilots used the suits until the first-generation 

aircraft were finally retired in 1989. David 

Clark Company fabricated 142 S-100 suits.39

S901J—INITIAL SUIT FOR 

SENIOR CROWN

In December 1962, 8 months after the first 

flight of the Oxcart, the USAF ordered six 

reconnaissance versions of the Blackbird as 

a rider to the CIA A-12 contract. Internally 

Lockheed referred to the new aircraft as the 

R-12, a reconfigured A-12 that was slightly 

longer and heavier to accommodate different 

reconnaissance systems and a second crewmember. The extra weight, and some additional drag from a reconfigured nose, resulted 

in a slightly slower maximum speed and a 

lower operating ceiling. By mid-March 1964, 

the manufacture of the six R-12s was well 

under way.

In August 1963, the USAF initiated its 

own procurement (not through the CIA) 

of 25 additional aircraft under the Senior 

Crown contract, for a total of 31 Air Force 

aircraft. The existence of this variant of the 

Blackbird family became public on July 24, 

1964, during a speech by President Lyndon 

B. Johnson: “I would like to announce the 

successful development of a major new 

strategic manned aircraft system, which will 

be employed by the Strategic Air Command. 

This system employs the new SR-71 aircraft, 

and provides a long-range advanced strategic 

reconnaissance plane for military use, 

capable of worldwide reconnaissance for 

military operations. The Joint Chiefs of Staff, 

when reviewing the RS-70, emphasized the 

importance of the strategic reconnaissance 

mission. The SR-71 aircraft reconnaissance 

system is the most advanced in the world. The 

aircraft will fly at more than three times the 

speed of sound. It will operate at altitudes in 

excess of 80,000 feet.”40

Contrary to the popular belief, the President 

did not misread his speech when referring 

The Lockheed SR-71 “Blackbird” became the Air Force’s 

primary user of full-pressure suits. Designed by Kelly Johnson 

at the Skunk Works, the two-seat SR-71 was capable of 

cruising at Mach 3 and 80,000 feet. Surprisingly, this was 

somewhat slower and lower than its CIA A-12 cousin.

Courtesy of Lockheed Martin Aeronautics
323

The SR-71 used a much more advanced ejection seat than 

the earlier A-12 operated by the CIA, necessitating a new 

pressure suit. In response, David Clark Company developed 

the S901J, which quickly became popular among pilots 

and eventually contributed ideas and concepts into the 

mainstream (nonblack-world) pressure suit business.

Tony R. Landis

to the aircraft as the SR-71. It was standard 

practice in those days to have an official White 

House stenographer taking a shorthand verbatim transcript of what the President said, to 

be used later for the official press release. In 

all three places where President Johnson said 

“RS-71,” the stenographer heard incorrectly 

and inserted “SR-71.”41 The stenographer’s 

copy became the official press release that was 

passed out to the 315 people in attendance at 

the State Department that day.

At the end of October 1964, the first Senior 

Crown aircraft was ready to begin the 

overland journey followed by all Blackbirds. 

However, unlike the A-12 and YF-12s before 

it, the journey would lead to new Lockheed 

facilities located at Air Force Plant 42 in 

Palmdale, CA, only 50 miles from Burbank. 

All the earlier aircraft had gone to Groom 

Lake for their first flights, but the SR-71 

would fly from Plant 42, which is officially 

known as the Air Force Production Flight Test 

Facility. On December 22, 1964, Lockheed 

test pilot Bob Gilliland took the first SR-71 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

324

Like most operational Air Force aircraft, the SR-71 had a 

seat kit that contained emergency supplies in case the pilot 

needed to eject. Included in the seat kit were a life raft, 

dehydrated food, a radio, dye marker, a knife, medical 

supplies, and suntan lotion.

NASA

(61-7950) on its maiden flight. (As a safety 

precaution, the back seat was empty.) 

Coincidently, on the same day, 150 miles 

to the northeast, the M-21 mothership was 

making its first flight from Groom Lake.

In early 1965, the growing SR-71 fleet was 

moved to nearby Edwards. The first six 

SR-71s were allocated to flight-test and, along 

with the three YF-12s already stationed there, 

a total of nine Blackbirds were operated by the 

newly activated YF-12/SR-71 Test Force. The 

first of two SR-71B trainers (61-7956) made 

its maiden flight on November 18, 1965, and, 

after a brief time at Edwards, became the first 

SR-71 to be delivered to the 9th Strategic 

Reconnaissance Wing at Beale AFB, CA, on 

January 7, 1966.

On February 8, 1965, Joe Ruseckas at David 

Clark Company sent the Senior Crown program office a technical proposal for a new suit 

to support the SR-71. The Air Force finalized 

the purchase specification on November 29, 

1966. Interestingly, the specification was only 

47 pages long and never once mentioned the 

program name or aircraft type.42

Because of differences in the ejection seats 

(the A-12 used a nonstabilized seat while the 

SR-71 used a much more sophisticated stabilized seat) and oxygen systems, the A-12 and 

SR-71 could not use the same pressure suits. 

David Clark Company developed an entirely 

new S901J Pilots Protective Assembly (PPA) 

for the SR-71. The Senior Crown program 

office continued to use the “GN” prefix 

originally assigned by Oxcart to “Northeast 

Manufacturing” (the David Clark Company) 

for its part numbers, and therefore, the S-901J 

suits were part number GN-S901J.43

The S901J was based on the late-model 

S901H used on the A-12 but incorporated 

new requirements and lessons learned from the 

older program. Perhaps the most noticeable 

difference was that the aircraft oxygen hoses 

no longer attached directly to the controller on 

the abdomen. Instead, two hoses ran from the 

aircraft to the right rear corner of the seat kit, 

which included an emergency oxygen supply. 

Dual-seat kit hoses with quick-disconnects 

in turn connected to helmet hoses integrated 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

325

A David Clark Company 

S901J suit with the original 

sliver exterior cover. S901J 

suits were later retrofitted 

with white, then brown 

exterior covers in an attempt 

to reduce cockpit instrument 

washout from sunlight 

reflecting off the suit. 

Courtesy of the David Clark 

Company, Inc.

into the center rear of the helmet. The neck 

ring was based on the design developed for the 

Gemini spacesuit and included a pass-through 

for helmet ventilation. The sealed bearing was 

integrated on the suit side rather than the helmet side of the neck-ring disconnect.44

The sage-green, oxford-nylon cloth innercomfort liner was attached using Velcro and 

could be easily detached for cleaning. The 

ventilation duct assembly consisted of a network of channels fabricated of neoprene bladder cloth. The channels contained a series of 

stainless steel springs enclosed in a nylon mesh 

to provide paths for cooling air and three antiblock assemblies covered the relief valves and 

suit pressure controller opening. The coated 

ripstop nylon fabric gas container included a 

pressure-sealing slide fastener that extended 

from the center back, through the crotch, 

and terminated in front just below the waist. 

Restraint bladder boots, designed to incorporate both bladder and restraint features, 

were cemented to the gas container above the 

ankles. These were made of coated nylonoxford cloth, with cuffs made from Dacron 

and Nomex.45

The Link-Net restraint assembly had takeup 

laces located at each wrist for individual 
326

The S901J suit included a fully integrated parachute 

harness, an automatic water-activated flotation system, 

urine collection system, and an optional inflatable thermal 

protective garment. 

Courtesy of the David Clark Company, Inc.

length adjustment. Takeup panels, located 

at the top of the pressure-sealing slide fastener 

and around the waist, allowed vertical trunk 

adjustment. Takeup cords at the inseams 

and outseams allowed leg-length adjustments. 

The restraint assembly was stitched to the 

gas container at the pressure-sealing slide 

fastener, and molded reinforcement rings 

attached to the Link-Net were cemented to 

the gas container at the hardware openings. 

A nylon cloth-restraint cover between the 

exterior cover and the restraint assembly pre-

vented the parachute harness from damaging 

the Link-Net. The suit used the same urine 

collection system introduced via modification 

on the S901H.

The white Nomex exterior cover provided 

thermal and physical protection for the 

restraint assembly and gas container. Openings allowed the parachute harness straps and 

other hardware to pass-through the exterior 

cover. The cover included box-type pockets 

on each thigh and calf, a knife pocket on the 

inside of the left thigh, and pencil pockets on 

the lower right leg and upper left sleeve. In 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

327

NASA test pilot Don 

Mallick poses with the 

second Lockheed YF-12A 

(60-6935) in his S901J 

full-pressure suit. Note the 

silver gloves used with the 

otherwise all-white suit and 

boots. The white exterior 

cover was developed in 

response to pilot complaints 

about reflections from the 

aluminized exterior covers 

used by many earlier S901-

series suits. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

328

This S970 helmet has a PPG glass visor with an integrated 

heating element. Initially, the designers at David Clark 

Company used an acrylic visor on the S901J helmet as a way 

to reduce weight. However, various operational considerations 

drove the Air Force to require glass visors for the front-seater, 

although the reconnaissance-systems operator in the back seat 

could (and usually did) wear an acrylic visor. 

Courtesy of the David Clark Company, Inc.

addition, a manifold pocket was located over 

the controller opening, a hose-excess pocket 

on the upper-center back, and a holddownstrap pocket on the upper left chest. Slide 

fasteners attached the exterior cover at the 

collar, gloves, restraint bladder boots, and 

torso harness liner.46

A parachute harness was integrated with 

the exterior cover, as was a floatation system 

located outside the harness, except for an area 

at the top of the shoulder. The floats were 

laced to the exterior cover around the neck 

area and passed under the arms and into pockets on the front of the exterior cover. A carbon 

dioxide cylinder and lanyard were attached to 

the inner left side and an oral inflation tube to 

the outer left side.47

The palm area and inner sides of the glove 

fingers were made from black-dyed chrometanned sheepskin leather. Initially, the 

remainder of the outer glove was made from 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

329

Table 7—Comparison of USAF Full-Pressure Suits Available in 1967

A/P22S-2 A/P22S-4/6 S901J

Contruction Bladder, Link-Net, 

and exterior cover

Bladder, Link-Net, 

and exterior cover

Bladder, Link-Net, 

and exterior cover plus 

separate outer garment

Entry Zipper U-Entry Rear Entry Rear Entry with 

reinforcing zipper

Ventilation Torso, arms and legs Extended to head Extended to hands 

and head

Sizing Eight Eight Twelve

Helmet No drinking port Drinking port with 

mechanical seal

Drinking port with 

mechanical seal

Circumferential 

spray bar

Interrupted spray bar Circumferential spray 

bar

Fixed microphone Adjustable 

microphone

Adjustable 

microphone

Warning-type antisuffocation deviceWarning-type antisuffocation deviceNo warning

Floatation Gear External Built-in External

Inner Suit Fixed Removable Removable

Source: Kent W. Gillespie and John R. Hochwalt, “The Design Requirements, 

Description, and Functional Operation of the A/P22S-4 and A/P22S-6 High-altitude, 

Flying Suits,” ASD-TR-70-58, April 1971. 

aluminized Nomex, but this changed over the 

years to the same white Nomex used on the 

exterior cover. A hinged palm restraint ran 

through a nylon sleeve in the palm area to 

prevent ballooning. Flocked neoprene inner 

booties were restrained by sage-green nylonoxford-cloth booties. White leather outer 

boots were worn over the pressure booties; the 

white color was selected to help reflect radiated heat. A slide fastener was used to expedite 

boot donning and doffing, while laces across 

the instep allowed personal sizing.48

Other changes included using nickel instead 

of cadmium-plated hardware, as in previous S901 suits, due to cadmium’s deleterious 

effect on the titanium used to manufacture the 

SR-71. Somewhat confusingly, the A-12 and 

YF-12A used identical titanium construction. 

The suit conformed to the standard 12-size 

tariff, with socks now available in 6 sizes. The 

coverall and gloves weighed 14 pounds, the 

exterior cover and harness 10 pounds, and the 

helmet 7 pounds, for a total of 31 pounds.49

A new dual suit controller was designed for 

the S901J that was smaller and lighter than 

the one used on the S901H. The new controller still used two separate aneroids, either of 

which could operate the suit independently of 

the other. The primary aneroid was set to an 

absolute pressure of 175 ± 7 mm Hg and the 

secondary aneroid was set at 165 ± 7 mm Hg. 

This new controller used an elegant design 

that did not require an external pilot (oxygen) 

pressure source as with prior controllers, but 

rather used suit (bleed) pressure for the necessary pressure control. This design has been very 

successful and remains in use for Air Force and 

NASA pressure suits as of 2011. Two relief 

valves, located on the outside of each hip of the 

coverall, were set at 4.5 ± 0.5 psi.50
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

330

On September 13, 1974, the Air Force used an SR-71 

(61-7972) to set a speed record from London to Los 

Angeles (2 weeks earlier, the same aircraft had set a record 

from New York to London). The flightcrew was Capt. 

Harold “Buck” Adams (pilot) and Maj. William C. “Bill” 

Machorek, both wearing S901J full-pressure suits. The 

total time for the record flight was 3 hours, 47 minutes 

and 36 seconds. Adams and Machorek had covered nearly 

5,463 miles at an average speed of 1,435.587 mph.

U.S. Air Force
331

It appears the S901J suit came in colors other than white. 

Here is NASA test pilot Thomas C. McMurtry and flighttest engineer Vic Horton after McMurtry’s first flight in the 

YF-12A, on December 14, 1977.

NASA

The S901J helmet was less complicated than 

the A/P22S-2 helmet. For instance, the previous pneumatic seal around the visor was 

replaced with a Gemini-style static seal that 

was activated mechanically via a visor-closing 

bailer bar. Designers moved the face seal farther forward to provide maximum headroom 

in the helmet and decrease the volume of the 

breathing space. The face seal consisted of a 

neoprene-coated fabric, a neoprene face seal, 

and a malleable aluminum frame. The microphone was mounted on the helmet shell with 

an external adjusting knob located front left, 

under the visor opening.51

The S901J helmet shell was based upon the 

original S901 shell with minor changes to 

accommodate new pressure controls and 

a compression sealed visor assembly. This 

replaced the pneumatic seal used on the 

earlier S901 helmets. A subsequent need for 

increased internal headroom for some crewmembers resulted in the development of a 

“bumped out” S901J helmet, where the back 

section of the helmet shell was enlarged.52

David Clark Company molded the helmet 

from a mixture of milled fiberglass, epoxy 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

332

The difference between the original U-2s (such as the 

NASA U-2C in the foreground) and the later big-wing 

U-2Rs (NASA ER-2s) is readily apparent. The U-2R was 

a much larger aircraft with a roomier cockpit that finally 

allowed the pilots to wear full-pressure suits. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

333

The U-2R eventually grew large “super pods” on each 

wing to house additional sensors and equipment. Fortyfive years after its first flight, the U-2 is still a valuable 

national asset. Over the years, the aircraft has received a 

turbofan engine and a glass cockpit, becoming the U-2S. 

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

334

resin, hardener, and fiberglass cloth that was 

heat cured at 150 oF for 60 minutes. After the 

shell cooled, holes were drilled for wiring and 

hardware, and a metal disconnect ring was 

attached to the bottom of the shell. A molded 

silicone-rubber gasket was bonded around 

the visor periphery to form an airtight seal 

when the visor was down and locked. A black 

neoprene spray bar was bonded around the 

interior of the face opening. A series of holes 

in the spray bar discharged oxygen to keep the 

visor defogged. A drinking port with a springaction door was located offcenter to the right. 

The helmet liner, available in four sizes instead 

of three, was a molded neoprene foam material 

called nopcofoam with a deerskin covering.53

An oxygen-pressure-piloted anti-suffocation 

valve located on the left side of the helmet just 

above the neck ring opened automatically if 

the suit lost its oxygen-pressure source. However, many pilots did not like the J-suit antisuffocation valve since it provided no warning 

of complete loss of oxygen pressure.54

Originally, the helmet used a gold-coated 

acrylic visor. After an in-flight accident that 

implicated visor reflections, PPG developed 

an anti-reflective-coated laminated glass 

visor with heating filament wires between 

the layers of glass for defogging. Subsequently, the SR-71 flight manual required 

the front-seater to wear a glass visor, but the 

back-seater generally wore an acrylic visor; 

they were interchangeable.55

The helmet holddown system consisted of 

an endless stainless steel cable that passed 

through a nylon pulley in front, metal cable 

guides on either side of the helmet disconnect 

ring, and through a nylon pulley in the back. 

A strap adjustment assembly in the front pulley allowed the pilot to control the amount of 

helmet rise.56

Each suit came with a helmet bag and a 

30-by-12-by-14-inch suitcase equipped with a 

Yale padlock. Over the course of several years 

beginning in 1966, David Clark Company 

fabricated 148 S910J suits for Senior Crown.

Although the first common suit that could 

officially be used in both the SR-71 and U-2R 

did not come until the S1031C in 1989, it 

appears that pilots at Lockheed Skunk Works 

wore modified S901Js on U-2R test flights 

beginning sometime before 1968. The primary 

modification was a minor change to the lower 

end of the helmet oxygen hoses and a tee block 

that mated the aircraft, seat kit, and helmet 

oxygen hoses. A similar modification was performed on a limited number of S1030 helmets 

to allow their evaluation in the U-2R.57

S1010—A SUIT FOR THE 

DRAGON LADY

Over the years, Kelly Johnson had been tinkering with advanced U-2 versions, beginning 

in September 1963 with a modified U-2C 

sometimes referred to as the U-2L (“L” probably stood for “long” or “lengthened” instead 

of being an official designation). Two further 

years of refinement resulted in the Lockheed 

Model CL-351, and in August 1966, the Air 

Force awarded Skunk Works a contract to 

begin development of the U-2R, with the “R” 

meaning “redesigned” or “revised”; however, 

this time the designation became official. 

As finally built, the U-2R was a completely 

new airplane, sharing nothing but its general configuration with the first-generation 

airplanes. The U-2R was almost 40 percent 

larger than the original U-2, with a 23-foot 

increase in wingspan. To the pilots, perhaps 

the most welcomed change was a larger cockpit. The U-2R pilots enjoyed the luxury of a 

full-pressure suit and a zero-zero ejection seat. 

Kelly Johnson and his design team placed 

significant emphasis on increasing range and 

endurance since the first-generation U-2 suffered from an inherent fuel-capacity limitation 

and its endurance rarely exceeded 9 hours. 

Although in-flight refueling was added to a 

few early U-2s, the aircraft’s range was marginal for many missions. The U-2R carried 

considerably more fuel and missions in excess 

of 14 hours became possible, but it was rarely 

flown due to the physiological limitations of 

the pilot, even with the new full-pressure suits.

On May 25, 1967, personnel from the CIA, 

David Clark Company, Firewel, Lockheed, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

335

David Clark Company introduced a urine-collection system 

as a modification to the S901H and used the same system on 

many later suits. The urine-collection system, for men only, 

consisted of an inner hose connected to an external catheter, a 

release valve, and an external hose attached to a storage bag 

mounted on the aircraft.

Courtesy of the David Clark Company, Inc.

and USAF met in Burbank to discuss the final 

configuration of the U-2R cockpit, pressuriza-

tion system, escape system, seat kit, parachute, 

and pressure suit. A design review of the new 

David Clark Company S1010 PPA was held 

in Worcester in June 1967, and a review of the 

aerospace ground equipment and test fixtures 

was held at Firewel in Buffalo later that month. 

The company began fabricating a prototype 

suit in July. The first S1010 suit was not 

ready for flight-test until September, so in the 

interim, several Oxcart S901 suits were modi-

fied to work in the U-2R for Lockheed test 

pilots. Lockheed test pilot Bill Park, who had 

previously flown the A-12, made the first U-2R 

flight using Article 051 (N803X, 68-10329) 

on August 28, 1967, from the CIA facility at 

North Base on the edge of Edwards AFB.58

In general, the S1010 was similar to the S901J 

but with oxygen and electrical connections 

tailored for the cockpit of the U-2R. The suit 

included a fully integrated parachute harness, an automatic water-activated flotation 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

336
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

337 Above and photos on page 336: Donning the S1010 

was not as difficult as one might expect, but it was a 

complicated procedure and generally went much better 

with an experienced suit technician assisting. The process 

begins with the wearer putting his feet in the pressure 

booties, raising the suit to the thighs, then putting the 

head and shoulders into the suit. The final steps were 

donning boots, attaching the helmet, and putting on 

the gloves.

Courtesy of the David Clark Company, Inc.

system, and an optional inflatable thermal 

protective garment. Given the long-duration 

missions of the U-2R, Joe Ruseckas and Ed 

Dubois at David Clark Company developed a 

urine-collection system for the S1010, and the 

company subsequently retrofitted this system 

to numerous other pressure suit models.59

An entirely new, third-generation helmet was 

designed for the S1010, and the David Clark 

Company designers made every attempt to 

reduce head-borne weight to minimize pilot 

stress and fatigue during long missions. They 

accomplished this by removing the breathing 

regulator and oxygen supply system from 

the helmet and relocating it in the coverall. 

In addition, the coverall helmet-disconnect 

bearing assembly was integrated with the 

helmet via a soft neck section at the base of 

the helmet shell so that the weight of the 

neck ring would not be head borne. They also 

enlarged and reshaped the S1010 helmet shell 

to increase headroom, relative to the S901J.60

The coverall and gloves weighed 14 pounds, 

the exterior cover and harness 10 pounds, and 

the helmet 7 pounds, for a total of 31 pounds. 

The entire suit, minus helmet, could be folded 

into a 2.7-cubic-foot package. The coverall 

and gloves were custom tailored for each 

U-2R pilot, while the helmet came in one size 

with five interior cushion sizes. David Clark 

Company also fabricated custom S1010 suits 

for Republic of China Air Force (RoCAF) 

pilots that flew the U-2R for the CIA from 

1969 until 1974. Project pilots began showing 

up in Worcester during late 1967 to be measured and fitted for the new suits.61
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

338

minimize helmet-induced stress and fatigue. 

Designers explored a nonconformal dome 

helmet that completely eliminated headborne weight and provided freedom of head 

movement within the helmet without the 

rotational torque (neck stress) associated with 

conformal helmets. Designated S1010D 

(D for dome; there were no A-C helmets), this 

nonconformal helmet used a large moveable 

visor (a considerable challenge given the need 

for highly reliable sealing under pressure) that 

provided excellent visibility. The pilot wore a 

skullcap communications carrier with a microphone and earphones. The prototype S1010D 

helmet was fully qualified, and completed 

The Air Force also procured two variants 

of the S1010. The S1010A had the breathingoxygen regulator, communications gear, parachute harness, and flotation device mounted 

integrally. The S1010B moved the regulator 

and communications gear back to the helmet 

while the parachute and floatation gear formed 

part of a separate harness worn over the suit. 

In all, David Clark Company produced 

151 S1010 suits of the various models.62

During 1978, David Clark Company began 

designing a new helmet to replace the S1010 

units when they reached the end of their services lives in 1981. The primary goal was to 

David Clark Company 

fabricated custom suits for 

Republic of China Air Force 

(RoCAF) pilots that flew 

the U-2R from 1969 until 

1974. The Chinese pilots 

were generally smaller than 

their American counterparts.

Courtesy of Clarence J. P. Fu 

Collection

The S1010B featured a harness-and-flotation system 

integrated into a vest that was worn over the pressure suit. 

Other differences from the S1010 were the location of the 

neck mobility joint to the suit side of the helmet-to-suit 

neck-ring disconnect and the routing of the oxygen and 

communication umbilicals directly into the helmet.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

339

The S1010 helmet moved the face seal further forward to 

reduce the volume of the breathing space and allow more of 

the head to be ventilated with suit gas. The major change 

was using a bailer bar to mechanically compress a static visor 

seal instead of the complicated pneumatic seal used on earlier 

S901 helmets. A similar technique had been used on the 

Gemini spacesuits.

Courtesy of the David Clark Company, Inc.

The S1010 helmet was designed to minimize head-borne 

weight by placing a softgoods section at the bottom of the 

helmet shell to offload the nexk ring weight. The designers 

also placed the breathing regulator and oxygen system in the 

coveralls. Oxygen was released into the helmet via a plenum 

in the neck ring. Further streamlining was accomplished 

by routing the communications cord internally as shown 

here. The S1010 helmet hold-down was generally similar 

to the S901 and A/P22S series suits. An endless stainless 

steel cable that passed through a nylon pulley in front, metal 

cable guides on either side of the helmet disconnect ring, 

and through a nylon pulley in the back. A strap adjustment 

assembly in the front pulley allowed the pilot to control the 

amount of helmet rise.

Courtesy of the David Clark Company, Inc.

operational test and evaluation (OT&E) in a 

U-2R, albeit with mixed results. The prototype helmet-support system consisted of foam 

pads of varying thickness integrated under 

the coverall neck ring to support the helmet 

on the shoulders at the desired height location. Pilots complained this was unsatisfactory 

because it interfered with the parachute riser 

and shoulder harness and provided inadequate 

fore-aft stability. Consequently, the USAF 

decided to use a variant of the S1030 helmet 

(subsequently dubbed the S1031) on the new 

U-2R PPAs when they replaced the S1010 

beginning in 1981.63

S1030—IMPROVED SENIOR 

CROWN SUITS 

In 1977, David Clark Company developed 

the S1030 PPA as a replacement for the S901J 

used in the SR-71. This rear-entry suit introduced several innovative features, including 

compression-sealed hardware (eliminating 

adhesives), a thermal-protection garment 

integral with the gas container, and a modular 

(field-removable) gas container made from 

heat-sealable, urethane-coated nylon taffeta 

fabric. The designers created a separate retainer 

assembly to contain an integrated parachute 

harness and a fully redundant, automatic 

flotation system that had improved coldtemperature performance and water-activated 

inflation devices. The S1030 also included 

the drinking port and urine-collection system 
340

The S1030 supported female pilots like NASA’s Marta 

Bohn-Meyer, in front of an SR-71B (61-7956/NASA 831) 

on February 27, 1992. Bohn-Meyer was the chief engineer 

at the Dryden Flight Research Center until she was killed 

while practicing for the 2005 U.S. National Aerobatic 

Championships when the Giles 300 aerobatic aircraft she 

was piloting crashed in Yukon, OK. The cause of the crash 

was deemed the catastrophic failure of the front hinge of the 

canopy, which apparently incapacitated her.

NASA

that had been added to the S901H via retrofit. 

The S1030 coverall came in the 12 standard 

sizes, with 8 sizes of bladder boots, 12 sizes of 

gloves, and a single helmet size with 3 cushion 

sizes.64 Each suit cost approximately $30,000 

and lasted 10–12 years. The suits were typi-

cally inspected every 90 days, or 150 hours, 

and overhauled every 5 years.65

David Clark Company developed a new 

helmet that featured greater headroom, a 

positively vented cushion assembly, a dropin breathing regulator, and improved head 

impact protection. The designers also reduced 

the weight of the oxygen system weight and 

eliminated legacy on-off valves by using a 

novel regulator sensing line shut-off valve 

keyed to the visor position via a rotating visor 

pivot pin. Other novel features included a 

modular drinking port, modular anti-suffocation valve, a more reliable takeup assembly, a 

more maintainable visor sealing and locking 
341

NASA research pilot Ed Schneider prepares for his first SR-71 

flight on October 18, 1994, wearing his S1030 suit. 

NASA

mechanism, integrated lower-torque (thrust) 

bearing, and an improved (amplified) noisecanceling microphone and flat cable electrical 

harness integrated to the interior surface of 

the helmet shell. The prototype S1030 helmet 

was fully qualified and completed its OT&E 

during flight tests in an SR-71. Despite generally positive evaluations, the USAF decided to 

revert to the bumped-out S901J helmet shell 

for the production S1030 helmet, albeit with 

the improved on-off valve, a larger drinking 

port, and a modular anti-suffocation valve.66

The complete S1030 ensemble consisted of 

six layers including long underwear, comfort 

liner, ventilation layer, double-walled gas 

container, restraint layer, and a Fypro-fabric 

exterior cover that was the gold-orange color 

referred to as “old gold.” However, at least one 

suit was fabricated in a medium-blue color.

The S1030 began replacing the S901J in late 

1978 and remained active until 1996 when it 

was replaced by the S1034, although by that 

time the SR-71 had been retired from USAF 

service and the only three flyable airplanes 

were operated by NASA. David Clark 

Company produced 115 S1030 suits.67
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

342

Although the new S1030 helmet was generally well received by the pilots, the Air Force 

decided to replace it with the bumped-out version for the S901J helmet for production 

suits. Some of the more significant items include (1) oxygen-system valve, (2) helmet-pad 

adjustment knob, (10) microphone, (17) visor, (18) helmet bag, (23) oxygen spray bar, 

(29) cushion assembly, (30) face seal, and (34) hose assembly.

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

343

Officially, all S1030 suits were “old gold” Fypro, but there was at least one medium-blue suit. This is Lt. Col. Joseph T. “J.T.” 

Vida (left, in the blue suit) and Bredette C. “B.C.” Thomas, Jr. at Norton AFB, CA, on November 16, 1986. 

Tony R. Landis

The adjustments on the 

restraint layer of the S1030 

were generally similar to 

other modern full-pressure 

suits using laces to tighten 

or loosen a fabric panel 

underneath.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

344

On its last flight, on March 6, 1990, Lt. Col. Raymond E. “Ed” Yielding and Lt. Col. Joseph T. “J.T.” Vida set three world speed records in SR-71A (61-7972). One of these involved flying 

1,998 miles from Los Angeles to Washington, DC, in 1 hour, 4 minutes, and 20 seconds, averaging 2,144.83 mph. At the flight’s conclusion, they landed at Washington-Dulles International 

Airport and turned the airplane over to the Smithsonian’s National Air and Space Museum.

Courtesy of Lockheed Martin Aeronautics
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

345

The S1031 replaced 

the S1010 for all U-2R 

operators during the early 

1980s. For all intents, 

the suit was a variant of 

the S1030 developed for 

the SR-71 with the major 

changes being the necessary 

interfaces to mate with 

the airplane.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

346

The S1031 floatation device kept the pilot mostly vertical 

in the water, ensuring that water did not enter the antisuffocation valve on the helmet. David Clark Company 

spent considerable effort to make the suits as safe as possible 

following an over-water ejection; the memory of Ray Torrick 

drowning after ejecting from a Lockheed M-21 in 1966 is 

still fresh. 

Courtesy of the David Clark Company, Inc.

Below and photos on page 347: It was possible to self-don the 

S1031, but having assistance made the process much easier. 

Like all rear-entry suits, the process began by inserting one’s 

feet through the legs into the booties, pulling the suit up to the 

thighs, inserting the arms followed by the head and shoulders, 

then standing up and arranging the suit correctly on the torso. 

The rear zipper can be closed using a long lanyard, but suit 

technicians are usually present to ensure everything is aligned 

properly. Boots come next. After the suit is properly donned, 

the parachute harness is added. The helmet and gloves are 

next, flowed by pressure integrity testing in the physiological 

support area. The suited pilot then heads to the aircraft. 

Courtesy of the David Clark Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

347
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

348

Various views of the S1031 

helmet. The face seal is as 

far forward as possible to 

minimize the breathing 

space in front of the pilot. 

The oxygen hoses attach to 

the back of the helmet where 

they do not interfere with the 

pilot’s vision or movement. 

Note the bailer bar that 

provides mechanical pressure 

against the visor to ensure a 

tight seal.

Courtesy of the David Clark 

Company, Inc.

S1031—IMPROVED DRAGON 

LADY SUITS 

In 1981, David Clark Company developed 

the S1031 PPA as a replacement for the 

S1010 used in the U-2R. The resulting suit 

was nearly identical to the S1030 developed 

for the SR-71 except for different oxygen and 

electrical interfaces dictated by the aircraft. 

These interfaces precluded using a single type 

of suit in the two aircraft. In addition, special 

care was taken to limit the bulk on the front 

of the chest to minimize interference with the 

steering-wheel-type control column used in 

the U-2R. Like the S1030, the suit came in 

the standard 12 sizes and weighed approximately 35 pounds.68 The S1031 helmet was 

identical to the S901J-based production 

S1030 helmet except that it did not have oxygen system on-off valves (not required in the 

U-2R) and did not have an externally adjustable microphone bracket (never present on the 

S1010 helmet). The S1031 used the same “old 

gold” Fypro color as the S1030.69

The S1031 replaced the S1010 in service 

beginning in late 1982 and remained active 

until 1996 when it was replaced by the S1034. 

The suit was used by the USAF in the U-2R, 

U-2S, and TR-1, and it was used by NASA in 

the ER-2. A midproduction running change 

in the S1031 suit deleted the pocket on the 

left thigh. After a few suits were produced, a 

Velcro pad was added on the left thigh—same 

as had always been on the right thigh. David 

Clark Company fabricated 231 S1031 suits.70
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

349

In 1984, David Clark Company began investigating improved helmets in anticipation of 

the need to replace the S1030/S1031 helmet 

in the late 1980s. This study examined three 

different concepts: a lightweight version of 

the S1030/S1031 helmet, an improved version of the S1010D nonconformal helmet, 

and a “soft” clamshell Sokol-type helmet. The 

company fabricated engineering models of 

each concept, with the lightweight S1030/

S1031 helmet, designated S1030L/S1031L, 

ultimately being selected. It is noteworthy that 

the nonconformal helmet improvements made 

as a part of this effort, principally in helmet 

support and stability, eventually benefited 

NASA when it became part of the S1032 

Launch Entry Suit and, later, with the S1035 

Advanced Crew Escape Suit.71

S1031C—COMMON SUIT

David Clark Company developed the S1031C 

PPA in 1989 as a common replacement for 

the S1030 and S1031 PPAs for use in the 

SR-71 and U-2R. Developing a common suit 

for use in aircraft with different interfaces 

was accomplished by designing a parachuteharness/retainer assembly and urine-collection 

system that was reconfigurable in the field for 

use in either aircraft; this was accomplished 

by selecting either the S1030 or S1031 helmet 

for use with S1031C coveralls. Additionally, 

the S1031 retainer assembly was standardized for use with the S1031C PPA because of 

its lower frontal bulk (compared to S1030). 

Thus, the S1031C PPA was a hybrid S1030/

S1031 system based largely upon mid-1970s 

(S1030) pressure-suit technology.72

All previous urine-collection systems had 

passed fluid to storage containers mounted 

on the aircraft, a concept that complicated 

aircraft maintenance and posed some risks 

if a spill occurred. David Clark Company 

designed several configurations of internal 

urine-collection systems that were flighttested using S1031 suits. However, none 

were considered satisfactory, mostly due to 

leakage. Although David Clark Company 

designers still thought it possible to develop 

an acceptable internal-collection system, its 

increased complexity, and the limited internal 

(coverall) storage volume appeared to offset 

the advantages to be gained. For the time 

being, at least, aircraft-mounted urine storage 

would continue.73

The S1031C began replacing S1030 and 

S1031 suits in 1991, and David Clark 

Company fabricated 60 S1031C suits.74

The Air Force uses “crew 

vans” similar to the NASA 

astronaut van. This pilot 

is wearing an S1034 in 

preparation for a U-2R 

mission in July 2004. 

The pilot gets to ride in 

the lounge chair, while 

the accompanying suit 

technicians ride on the 

bench to the left.

U.S. Air Force
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

350

Table 8—S1034 Requirements Classification

Category Requirement

I 1. Comfort (unpressurized)

2. Visibility

3. Mobility (upressurized)

4. Tactility–Dexterity

5. Oxygen Breathing System

6. Communications

7. Aircraft Compatibility

8. Thermal (hot-cold) Protection

9. Glare Protection

10. Pockets

11. Ease of Donning and Doffing

12. Aesthetics

II 1. Drinking and feeding

2. Urine Collection

3. Valsalva

4. Altitude Protection

5. Mobility (pressurized)

6. Comfort (pressurized)

7. Leakage (pressurized)

8. Structural Integrity

9. Maintainability

10. High and Low Temperature Storage

11. Durability

12. 5th to 95th Percentile Sizing

8. Anti-Suffocation Protection

9. Open Flame Protection

10. Laser/Flashblindness Protection

11. Explosive Decompression Protection

12. Chemical Biological Defense 

Protection

III 1. Ejection G Forces

2. Parachute Compatibility

3. Survival Kit Compatibility

4. Wind Loading Protection

5. Flotation Provision

6. Water Immersion Protection

7. Impact and Penetration 

Protection

Source: “S1034 Pilots Protective Assembly, Development & Qualification Final Report,” 

David Clark report DCR-3124-00, February 28, 1992.

S1034—IMPROVED COMMON SUIT

In late 1987, David Clark Company began 

developing a new suit to replace the S1030 

and S1031. This was a year before the company began developing the S1031C common 

suit. The goal was to develop a common suit 

that reduced crewmember stress and fatigue, 

with a secondary goal of reducing ground support and maintenance requirements. Unlike all 

previous suits, which had been obvious evolutions of the original A/P22S-2 and S901, what 

became the S1034 was largely a clean-sheet 

design, although it ended up looking and acting very much like an evolutionary suit.75

Designers began by categorizing the known 

requirements based on years of crewmember 

and maintainer experience with pressure suits. 

Requirements were placed into one of three 

general categories: Category I directly affected 

performance on every mission; Category II 

occurred frequently but not on every mission; 

and Category III occurred infrequently and 

usually only under emergency conditions. 

The relative order of individual requirements 

within each category was more subjective, with 

the designers basing the ranking primarily on 

previous experience. David Clark Company 

designers recognized that all of the requirements were valid, and the ranking was simply 

a method to prioritize their implementation.

None of these requirements was new, and all 

had been addressed, to varying degrees, by 

previous generations of pressure suits. For 

the most part, comments from crewmembers 

regarding the S1030 and S1031 series suits 

had been overwhelmingly positive. In the 

30 years since the MC-2 full-pressure suit 

was introduced for the X-15, David Clark 

Company had largely eliminated the problems 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

351

concerning comfort and mobility that had 

plagued suit development since Wiley Post. 

Nevertheless, wearing a full-pressure suit 

still induced pilot stress and fatigue, and 

maintaining the suits was somewhat laborintensive. The designers felt that a new 

generation of materials might offer significant 

improvements and took the opportunity to 

reevaluate their entire approach to pressure 

suits. According to Jack Bassick, the director 

of research and development at David Clark 

Company at the time:

A clean slate approach was used in the 

requirements-design trade study process, 

wherein each PPA requirement was 

carefully reconsidered and revalidated 

prior to being accommodated. 

Additionally, the relative importance 

of each requirement to the mission 

was weighed to ensure that low 

priority requirements did not exert a 

disproportionate amount of adverse 

influence on high priority requirements. 

Numerous mock-ups were fabricated for 

test and evaluation of various concepts 

throughout the requirements-design 

trade study process. Concepts considered 

ranged from full to partial-pressure 

coveralls, from single to multiple layer 

coveralls and from soft, non-conformal, 

fixed visor helmets to rigid, conformal, 

movable visor helmets.76

The conceptual design that emerged from the 

evaluation, however, was not terribly different from what had come before. By this time, 

the S1031C common suit was well along in 

development and, perhaps not surprisingly, 

the designers concluded that the S1031C concept offered the best approach. Nevertheless, 

the designers identified several developments 

that might reduce stress and fatigue, including 

a lightweight helmet, breathable-gas-container 

materials, low-torque bearings, and a better 

glove-disconnect design.77

During 1989, designers at David Clark 

Company fabricated an engineering 

model that used Gore-Tex fabric for the 

gas container.78 This breathable material 

allowed a lightweight garment that was more 

The S1034 is not much 

different visually than the 

suits it replaced, but modern 

materials allowed David 

Clark Company to make 

it much more comfortable 

and sustainable.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

352

During the 1950s, 

unfortunate human subjects 

wore pressure suits during 

cold-water evaluations. 

By the 1990s, researchers 

had turned to instrumented 

brass anthropomorphic 

dummies for such tedious 

and potentially dangerous 

tasks. This is the dummy 

used for the S1034 coldwater evaluations.

Courtesy of the David Clark 

Company, Inc.

comfortable, less bulky, easier to don and 

doff, and far simpler than the S1030/S1031 

gas container. In this context, “breathable” 

refers to the ability of the fabric to allow 

perspiration to pass in the form of water vapor 

while retaining air pressure. The breathable gas 

container allowed David Clark Company to 

minimize the amount of vent ducting within 

the suit. After a great deal of experimentation, 

designers chose a three-ply material: a nylon 

taffeta fabric for the outer ply; a Gore-Tex 

membrane for the waterproof, pressureretaining, breathable inner ply; and a nylon 

tricot fabric for the inner ply. Laboratory 

testing of the material showed its durability 

and launderability was comparable to the 

urethane-coated nylon taffeta fabric used 

for the S1030/S1031 gas container and that 

reliability, maintainability, and repair should 

be similar. Subjective evaluations indicated 

that it was more pliable with a better “hand” 

and should provide better comfort.79

The use of Gore-Tex allowed the designers to 

greatly simplify production, especially of the 

legs. Typically, full-pressure suits incorporated 

at least four layers including an inner comfort liner, gas container, restraint layer, and 

exterior cover that primarily provides flame 

and abrasion protection. In the design of the 

S1034 legs, the restraint layer and exterior 

cover were incorporated into a single layer 

of high-temperature woven fabric. Additionally, the S1034 vent ducts were incorporated 

directly to the gas container via integral channels that distributed vent air throughout the 

coverall, including the hands and legs.80

The designers selected a YKK (Yoshida Kogyō 

Kabushikigaisha, or Yoshida Manufacturing 

Corporation) pressure-sealing closure after the 

source for the legacy B.F. Goodrich closure 

vanished. Engineers closely monitored the 

performance of the new closure, first introduced on late S1031 suits, during extensive 

flight-test and operational evaluation with 

the S1031 and found it to be satisfactory. 

The YKK closure functioned both as a pressure sealing and restraint (structural) closure, 

thereby eliminating the need for two, independently operated slide fasteners.81

Surprisingly, the designers also eliminated 

Link-Net from the restraint layer on the legs, 

choosing instead to combine the restraint and 

exterior cover functions into a single layer 

of Nomex fabric that was shaped to provide 

adequate knee mobility and comfort. The 

S1031 torso and arm restraint and exterior 

cover designs remained largely unchanged, still 

making extensive use of Link-Net for comfort 

and mobility.82

During the 1980s, David Clark Company 

had developed the S1031L lightweight 

helmet, and it had already been through 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

353

The S1034 helmet is an 

evolutionary design based 

on the S1031L lightweight 

helmet designed several years 

earlier for the S1031 suit. 

Modern materials allowed 

an improved two-ply visor 

to be added to the design, 

along with smaller oxygen 

hoses and microphone.

Courtesy of the David Clark 

Company, Inc.

extensive flight-test and operational evaluation. The unit was functionally identical 

to the S1031 helmet but was fabricated of 

lighter materials. This helmet was used for 

the engineering model S1034, although 

David Clark Company developed a new 

two-ply heated visor that used an inner ply 

of polycarbonate to resist internal shattering 

and an outer ply of acrylic to provide scratch 

resistance. Additionally, they modified the 

helmet with smaller-diameter oxygen hoses 

and a lighter, smaller-profile microphone. 

Designers selected a modified version of 

the standard PPA helmet holddown system 

that used a sized cable and a simplified 

rear-anchor bracket. 

During the development of the S1034, the 

David Clark Company designers conducted a 

detailed review of alternate full-pressure glove 

designs and determined that it would be possible to improve comfort and mobility. This 

was based, at least partly, on a glove developed under a NASA-sponsored 8.3 psi glove 

program that consisted of an all-Link-Net 

restraint and a separate outer cover. However, 

that design was considerably more complex 

and expensive to manufacture. Given the limited benefits and significant costs, David Clark 

Company decided to stay with a modified 

version of the S1031 glove. 

The prototype S1034 gloves offered improved 

comfort, mobility, and dexterity by using a 

combination of flat and tucked patterning. 

Designers replaced the leather and nylon 

palm of the S1031 glove with a single layer of 

Nomex embossed with silicone for improved 

gripping and wear protection. They also 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

354

Lt. Col. Charles P. “Chuck” 

Wilson in the blue prototype 

S1034 in Taif, Saudi 

Arabia. One of the U-2S 

aircraft assigned to the 

4402nd Reconnaissance 

Squadron (Provisional) 

is behind the pilots. The 

other pilots are wearing 

S1031C suits.

Courtesy of Charles P. Wilson

introduced a new glove disconnect for the 

S1034 that featured the improved locking 

mechanism and low-torque bearings from the 

NASA 8.3 psi glove program. At the same 

time, better machining capability and the 

new locking mechanism allowed designers 

to increase the inside diameter so that it 

was easier to pass the hand through while 

maintaining the same outside diameter. 

This was especially important given the 

limited cockpit volume of the U-2R.83

An improved flotation system consisted of dual 

low-bulk flotation cells fitted with automatic 

water-activated inflators. This system provided 

about half-again as much water-displacement 

volume as the S1031, with less stowed bulk, 

reducing the potential for U-2R control 

column interference. The greater displacement 

volume also resulted in a much higher floating 

position, thus keeping the helmet further out 

of the water. 

Several pilots evaluated the engineering model 

S1034 and found it lighter, less bulky, more 

comfortable, easier to don and doff, and more 

mobile than the S1030/S1031. In addition, 

it appeared to be easier to maintain. Based on 

the positive results of this limited evaluation, 

in late 1989, the USAF authorized a full-scale 

development and qualification program.84

Having substantially improved the interior 

layers of the S1034, the David Clark Company designers conducted a search for new 

exterior cover materials based on flammability, 

strength, color, colorfastness, and durability. Flammability was a major concern since 

the exterior cover was the primary protection 

against open flame. The evaluation led designers to select two off-the-shelf Nomex fabrics. 

While other materials, such as Fypro or PBI 

(polybenzimidazole) offer superior flame protection, Nomex provided acceptable overall 

performance coupled with widespread availability and lower costs.85

Color is, almost by definition, a subjective 

choice. Since 1977, the S1030/S1031 had 

used “old gold” Fypro based on its combination of solar heat reflection, visible light 

reflection, and aesthetics. However, search 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

355

A mixture of colors. When they fabricated the royal-blue suit, 

they did not have any blue Velcro so the suit used standard 

sage-green patches. Also note the “old gold” gloves.

Courtesy of Charles P. Wilson

and rescue (SAR) personnel identified tan as 

the best color from a SAR perspective given 

worldwide operations. David Clark Company 

also identified blue as a possible alternate, 

based primarily upon its aesthetics and desirability by USAF pilots.86

Nomex is available from DuPont in a range of 

weaves, weights, and colors. Natural Nomex is 

white, and DuPont creates several other colors 

through a producer dyeing process that results 

in a colorfast fabric. However, in 1990, the 

only colors available from DuPont were natural, green, and blue. Solution dyeing, where 

natural Nomex is dyed, almost always by third 

parties, provides a wider variety of colors but 

generally lacks colorfastness, especially when 

exposed to the high-intensity ultraviolet light 

present above 50,000 feet. 

Below: The S1034 may be the last full-pressure suit fabricated in the United States. The only aircraft that currently 

require the use of pressure suits on a routine basis are the U-2 

(and its ER-2 cousin) and the WB-57Fs. The Government 

expects to phase both of these aircraft types out of service over 

the next decade. The retirement of Space Shuttle during 2011 

eliminated the only other routine user of pressure suits.

NASA
356

Lt. Col. Delewis “Dee” Porter wearing the third prototype 

S1034 suit at the U-2 test base in Palmdale, CA, during 

June 1991. Technicians noted the tan Nomex exterior cover 

soiled easily, and Porter found minor issues with the revised 

parachute harness, but overall everybody thought the garment 

was a significant improvement over previous pressure suits. 

Courtesy of the David Clark Company, Inc.

Nevertheless, David Clark Company ultimately selected a solution-dyed gold Nomex 

that was available in different weaves and 

weights. They chose a 5.5-ounces-per-squareyard poplin weave for the upper coverall exterior cover and a 5.9-ounces-per-square-yard 

gabardine weave for the leg restraint-exterior 

cover. As an alternate, the designers selected 

an off-the-shelf, solution-dyed, royal-blue 

Nomex in a 6-ounces-per-square-yard gabardine weave. This fabric was a bit heavier than 

necessary for the upper coverall exterior cover 

and resulted in a slightly heavier garment. 

The S1031 pocket configuration was selected 

for the S1034, although eliminating the expo-

sure garment allowed the designers to remove 

the oral-inflation hose pocket from the left 

thigh. As it did with the S1031, David Clark 

Company placed a large piece of Velcro on the 

right thigh for optional use, and beginning 

with the third S1034 suit, did the same on the 

left thigh.
357

Life support technician Jim Sokolik (left) assists Dee 

Porter in his S1034 suit into a NASA ER-2 (809) during 

January 2000. The ER-2 and the NASA DC-8 were based 

north of the Arctic Circle in Kiruna, Sweden, to study ozone 

depletion as part of Project SOLVE. Scientists had observed 

unusually low levels of ozone over the Arctic during previous 

winters, raising concerns that ozone depletion there could 

become more widespread, as with the Antarctic ozone hole. 

The NASA-sponsored international mission took place 

between November 1999 and March 2000.

NASA

David Clark Company designers used a 

slightly modified version of the S1031 urinecollection system in the S1034. The modifications included the addition of self-sealing, 

quick-disconnect connectors at the internal 

hose interface that reduced urine spillage dur-

ing the disconnect-doffing process and elimi-

nated the need for a separate safety clip.87

The S1034 urine-collection system supports 

both male and female wearers. It consists of an 

internal hose that connects with an external 

catheter or collector and an external release 

valve that connects to a urine receptacle 

mounted on the aircraft. The release valve is 

located in a pocket on the inside of the left 

leg. The male urine-collection system consists of underwear drawers and briefs that are 

modified with a circular opening at the front 

for integration with the urine duct. A female 

urine-collection system consists of a collector 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

358

assembly worn in conjunction with a support 

brief and female underwear drawers. These 

are modified with a slot-shaped opening 

at the front to integrate with the urine-collection system.88

The female collector (which is used only once) 

was originally purchased from a Governmentapproved source at a cost of several hundred 

dollars per unit. During 2000, after several 

months of research, Ed Dubois, on his own 

initiative, purchased several off-the-shelf 

incontinence products from a local drug store 

at a cost of several dollars per unit. Minor 

modifications allowed the product to interface 

with the urine-collection system in the S1034 

suit. Dubois’ wife tested the prototypes at 

home and, ultimately, a workable solution 

was found at an extremely reasonable cost.89

Designers considered several approaches for 

the S1034 helmet holddown assembly, including an automatic pressure-compensating 

design that eliminated the need to manually 

readjust the holddown upon pressurization. In the end, the designers believed that 

the benefits were not worth the additional 

complexity and cost. Instead, David Clark 

Company modified the S1031 design to make 

it somewhat simpler and lighter by replacing 

the adjustable length holddown cable with 

sized cables, eliminating any excess cable 

protrusions and the keeper sleeve at the rear. 

This allowed the use of a simple, low profile 

rear-cable anchor. The cables come in four 

sizes corresponding to the four basic pressuresuit sizes (small, medium, large, and extra 

large). The proper size cable is installed during 

the initial coverall fitting, with no subsequent 

adjustments required. The holddown assembly 

is capable of controlling helmet rise at operating pressures up to 5.0 psi.90

David Clark Company selected the standard 

dual-system pressure controller, first used on 

the S901J, based upon its redundant design, 

crewmember familiarity, satisfactory performance, pressure-schedule flexibility, and availability. David Clark Company designed the 

S1034 to be operated at 5.0 psi if the need 

arises, although 3.5 psi is the standard operating pressure. Prior study and preliminary 

testing showed the existing dual suit controller 

can be rescheduled to provide 5.0 psi, and the 

suit itself can withstand the pressure. However, a significant amount of mobility would 

be lost because of the higher pressure.91

The helmet includes a modular drinking port 

at a slightly different location that provides, 

“an optimum angle for probe insertion into 

the mouth.”92 The port also has a new seal 

that is easier to replace. A low-profile M-169 

microphone replaces the M-101 used on the 

S1030/S1031 helmets. Although the standard 

S1034 (and later S1034E) helmet provides 

a normal sunshade, laser and flashblindnessprotection visors are also available.

David Clark Company fabricated three S1034 

prototype suits for qualification testing. A size 

large-regular destructive-test unit (suit 001) 

and one medium-long flight-test suit (003) 

were fabricated with tan Nomex exterior covers. The second flight-test suit (002), in largelong, used a “Carolyn blue” Nomex exterior 

cover. The two flight-test suits were made for 

Lt. Col. Delewis “Dee” Porter and Lt. Col. 

Kenneth Sasine from the U-2R flight-test 

detachment at the Lockheed Skunk Works 

facility at Plant 42 in Palmdale, CA.93

The first suit (003) and helmet (103) arrived 

at Palmdale on June 20, 1991. This was 

Porter’s suit and he made the first flight of 

an S1034 in a U-2 and eventually logged 

145 flight hours wearing the garment. 

Technicians in Palmdale quickly found that 

the tan Nomex exterior cover soiled easily, 

but they did not attempt to clean it during 

the evaluation. Porter experienced some 

problems with the new parachute harness 

and floatation retainer assembly, and 

he complained of discomfort from the 

parachute harness across the buttocks. This 

was addressed by David Clark Company 

with a redesigned retainer assembly, but the 

parachute harness discomfort remained.94

Ken Sasine’s suit (002) and helmet (102) 

arrived in Palmdale on June 27, 1991. Sasine 

ultimately used the suit for 158 flight hours 

during the evaluation, and the blue exterior 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

359

The S1034E is the latest 

full-pressure suit helmet 

from David Clark 

Company. The “E” suffix 

was added to reflect the 

entire helmet was designed 

using an electronic 3-D 

modeling system. There were 

no S1034B–D versions, and 

the suit itself continues to be 

an S1034 (no suffix). 

Courtesy of the David Clark 

Company, Inc.

cover did not soil as easily as the tan on the 

other suit. Sasine complained of grainy and 

distorted optics causing eyestrain and headaches. Technicians replaced the helmet visor 

with a standard acrylic visor, and the hybrid 

acrylic-polycarbonate visor was returned to 

David Clark Company for evaluation.

Both pilots were impressed with the S1034 

suits, remarking they were more comfortable 

and provided better mobility than previous 

suits. They also liked the improved ventilation 

and the low-torque neck ring and glove disconnects. Technicians performed two periodic 

inspections on the suits during the evaluation 

with no discrepancies found and no maintenance required. The preparation time prior 

to a flight was cut by a third, mostly because 

the pressure sealing/restraint fastener did not 

need to be lubricated every time the suit was 

donned. In fact, the closure required lubrication only once during the evaluation.95

Nevertheless, Porter and Sasine recommended 

several minor changes. These included moving the breathing regulator manifold passthrough closer to the helmet shell to provide 

more internal headroom, moving the leglength adjustments to the exterior of the garment to allow easier sizing adjustments, and 
360

Fabricating a helmet is a complicated endeavor, as shown by 

the number of different fiberglass patterns required for the 

S1034E. Each helmet is largely handmade, due partially to 

the low production volume and the critically of the helmet 

to the pilot’s well being.

Courtesy of the David Clark Company, Inc.

reinstalling the S1031-style “butt pads” to the 

parachute harness to eliminate the discomfort 

experienced by Porter.96 Based on these results, 

David Clark Company began finalizing the 

design of the production S1034 suit. Designers also switched the exterior cover to a gold 

Nomex material, although some tan suits have 

also been fabricated.

All previous full-pressure suit sizing had been 

based upon USAF anthropometric data published in 1959. While developing the S1034, 

David Clark Company studied all available 

anthropometric data, including the latest 

available for female USAF flying personnel, 

to determine if the standard 12 sizes were 

still satisfactory. In the end, David Clark 

Company and the USAF agreed that these 

still accommodated the greatest percentage of 

USAF flying personnel, including females.97

The S1034 is available in 12 sizes, the retainer 

in 4 sizes, the gloves in 12 sizes, and the 

restraint boots in 5 sizes. The suit can also 

be custom fitted if needed for a particular 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

361

pilot or application. Both the S1034 and 

S1034E helmets come in a single size with 

five cushion sizes. The coverall and gloves 

weigh 12.5 pounds, the retainer weighs 

7.5 pounds, and the S1034 helmet weighs 

6.5 pounds. The suit (minus helmet) folds 

into a 2.7-cubic-foot suitcase. 

The S1034 began replacing the S1031 in 

the U-2R in 1996 and in the NASA ER-2 

in 1997. Sometime later, the suit began 

replacing A/P22S-6 suits used by the NASA 

WB-57F program at Ellington Field, although 

NASA continues to use A/P22S-6 helmets 

with its S1034 suits. The A/P22S-6 helmet has 

a single-system oxygen regulator (matching 

the WB-57F), while the S1034 helmet has 

a dual-system regulator (matching the U-2). 

By June 2010, David Clark Company had 

fabricated 314 S1034 suits for the Air Force 

and NASA.98 Like its predecessors, the S1034 

requires an overhaul every 6.5 years. The suits 

are returned to the David Clark Company for 

refurbishment, a process that generally takes 

30 to 60 days.

Not long after the S1034 entered service, 

designers at David Clark Company began 

investigating new helmet designs that might 

offer yet lighter weight and improved performance. This became more formal in 

June 1999, and during 2002, the company 

developed an engineering model of the nextgeneration helmet. David Clark Company 

provided this helmet to the U-2S (an updated 

U-2R) operations community for its initial 

assessment, which was favorable except for 

a concern about the helmet’s overall height 

with the visor lever in the straight-up position 

(visor opening and closing swing radius).99

The initial S1034 helmets would begin reaching the end of their service lives in June 2006, 

so in early 2003, the USAF approved a development program to finalize the configuration of the new helmet. A preliminary design 

review was held on June 17, 2003, and engineering development of the newly designated 

S1034E helmet commenced immediately 

thereafter. The “E” suffix was added to reflect 

the entire helmet was designed using an electronic 3-D modeling system and there were 

no S1034B-D versions, and the suit itself continues to be an S1034 (no suffix).

The S1034E helmet is slightly larger than the 

original S1034 “oversize” helmet to accommodate the largest heads and an optional 

impact liner, and it weighs approximately 

1 pound more than the standard helmet. 

The S1034E includes a thinner face seal for 

improved comfort, an optional integrated 

impact liner, and a comfort cushion cover that 

uses a “phase change” material to moderate 

extreme temperature swings. The S1034E also 

features a redesigned anti-suffocation valve 

mounted on top of the helmet to lessen the 

possibility of water entry and to improve the 

pilot’s ability to breath under zero-oxygenpressure conditions.100

In January 2005, prototype S1034E helmets 

were ready for operational evaluation in the 

U-2 to verify cockpit compatibility. Lockheed 

and USAF test pilots operating from Site 2 

at Plant 42 in Palmdale conducted six evaluation flights—three in a single-seat U-2S and 

three in a two-seat TU-2S trainer—between 

August 22 and October 18, 2005. Of the 

trainer evaluations, two were conducted in the 

forward cockpit and one in the aft cockpit.101

The pilots had various minor comments, 

including concern over some slight distortion 

in the visor that was traced to raw-material 

sources. Overall, the pilots confirmed that the 

S1034E was a suitable replacement for the 

S1034 helmet. David Clark Company began 

building production S1034E helmets in 2006 

to replace the earlier helmets as they reached 

the end of their service lives.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

362

Sidebar: 

The 

Shrinking 

Industrial 

Base

At the height of the Cold War, the 

United States industrial base was the 

envy of the world. There were a dozen 

aircraft manufacturers, a half-dozen 

engine manufacturers, and a large base 

of specialized companies that developed 

avionics, landing gear, and weapons. 

Nevertheless, the number of high-altitude 

protective-clothing manufacturers has 

always been small.

Although a fair number of companies manufactured G-suits during World War II and the 

immediate postwar years, there were only two 

with extensive development experience: Berger 

Brothers and David Clark Company. These 

same two companies largely took the lead on 

partial-pressure suits.

The development of full-pressure suits began 

during World War II with a half-dozen 

companies but ended abruptly when the 

Army cancelled the effort. Surprisingly, 

when the effort picked up again after the 

war, there were almost as many companies 

involved, and eventually Arrowhead, Berger 

Brothers, David Clark Company, Goodrich, 

ILC Dover, Space Age Control, and U.S. 

Rubber all developed full-pressure suits for 

the Air Force, Navy, or NASA. After winning 

the Apollo suit competition, ILC Dover 

decided to specialize in true spacesuits, and 

except for an occasional prototype, left the 

aviation pressure suit business.

But as the luster wore off the full-pressure suit 

concept, and the anticipated “thousands” of 

suits fell to a few hundred, interest faded. For 

most of the Cold War, David Clark Company 

fabricated all of the full-pressure suits for the 

CIA and USAF, while Goodrich manufactured suits for the Navy. A series of events that 

included the Navy deciding to abandon their 

operational suits (and NASA hiring their chief 

engineer) eventually drove Goodrich out of 

the business. This left David Clark Company 

as the sole supplier of full-pressure suits in the 

United States. This became so obvious to everybody that the Air Force stopped assigning 

military designations to the suits, simply using 

the David Clark model numbers instead.

Eliminating competition is never good, 

particularly when Government contracting 

and taxpayer money is concerned. However, 

if it has to happen—and the pressure suit 

market became so small it could not support 

multiple manufacturers—then having 

David Clark Company as the sole supplier 

was the best possible answer. David Clark 

Company is a small, employee-owned 

business and has proven many times over 

the years that it is willing to do what is best 

for its programs, regardless of contractual 

or funding limitations. Jack Bassick, a longtime employee and retired executive vice 

president, once wrote, “DCC continues to 

take seriously its self-imposed responsibility, 

initially promulgated by Mr. David Clark in 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 7: Special Project Suits

363

the 1940s, to preserve and develop further this 

national capability as best we can.”102

It has become increasingly difficult to maintain even a single company as an industrial 

base for full-pressure suits (a similar problem 

confronts the spacesuit business, but that is 

beyond the scope of this book). Throughout 

the last two decades of the 20th century, multiple programs required full-pressure suits: the 

SR-71 (Senior Crown), U-2 (Senior Year), 

and Space Shuttle. In 1999, the Air Force and 

NASA finally retired the SR-71, leaving only 

two programs. In 2011, NASA retired the 

Space Shuttle. Although most people consider 

it unlikely, the Air Force has announced the 

U-2 will be retired in 2012, replaced by a fleet 

of unmanned aerial vehicles. 

As of 2010, the U.S aviation pressure suit 

sustaining-engineering function is funded 

almost entirely through the Senior Year 

(U-2) program office, which is part of the 

576th Aircraft Sustainment Squadron, 

330th Aircraft Sustainment Wing, at Robins 

AFB, GA. Management at the David Clark 

Company has been pointing out for a number 

of years that their support staff is only “one 

deep,” meaning that only a single skilled 

person is available for certain critical tasks. 

Funding shortfalls within DoD have trickled 

down to the industrial base that supports the 

U-2, including David Clark Company. The 

lack of funding has several detrimental effects, 

most critically the inability to purchase longlead materials and replace vanishing vendors 

have resulted in a reduced inventory of 

operationally ready U-2 suits.

Sustaining engineering capability also 

diminishes with reduced funding. For the 

past 50 years, having a continuing sustaining 

engineering activity at David Clark Company 

(and Berger Brothers when they were still 

in the business) has allowed the Nation 

to respond rapidly to unforeseen needs 

in high-altitude protective equipment. A 

classic example is the timely creation of the 

S1032 Launch Entry Suit for the Space 

Shuttle Program in response to the 1986 

Challenger accident. Without an existing 

industrial base, this suit could not have been 

brought on line in a timely manner, with 

adverse impacts to what was one of America’s 

most visible technical achievements. This 

sustaining-engineering funding also allowed 

the development of the S1034 Pilots Protective 

Assembly, S1034E helmet, and coincidentally, 

the Space Shuttle S1035 Advanced Crew 

Escape Suit that is a variant of the S1034.

Reduced funding also makes it difficult to 

retain critical skills. For pressure suits, this is 

especially true of the softgoods disciplines, 

such as pattern design and grading, cutting, 

stitching, cementing, sealing, and Link-Net 

fabrication—skills that are no longer promoted 

in schools and need to be learned on the job. 

This is not to say that all industrial bases 

are worth saving. Technology marches on, 

and some industries are simply no longer 

required. There were once thriving businesses 

dedicated to making typewriters, IBM punch 

card machines, and floppy disk drives; but 

those businesses are no more, and, honestly, 

nobody misses them. The same will soon be 

true for incandescent light bulbs and cathode 

ray tubes, as newer, better technologies replace 

those items. Sometimes, it is simply time to 

move on.

Perhaps this is true of pressure suits. However, 

as with many highly specialized capabilities, 

once the pressure suit (and spacesuit) 

industrial base disappears, it will be very 

difficult to reconstitute. All of this bodes ill 

if the United States again finds itself in the 

position of needing high-altitude protective 

clothing for some, as yet unimagined purpose. 

The Nation needs to make a conscious 

decision regarding this capability, not just 

ignore it until it goes away.
8
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

365

8: Space Shuttle Pressure Suits

President Richard M. Nixon formally 

announced the Space Shuttle Program on 

January 5, 1972. Space shuttle was different from all spacecraft that had come before. 

Instead of the disposable capsules used by 

Mercury, Gemini, and Apollo, the new 

vehicle had wings and was reusable. NASA 

and the Air Force had ambitious plans that 

included a flight rate of one per week from 

launch sites in Florida and California. For the 

first time, non-professional astronauts would 

fly into space to perform experiments, service 

satellites, and deploy and retrieve payloads.1

NASA liked to talk about “airline-like” operations without the fanfare and preparation that 

accompanied the earlier programs. Designers 

envisioned a shirtsleeve environment for the 

occupants, eliminating the need for pressure suits, although spacesuits would still be 

required for extravehicular activities (EVA), 

such as servicing satellites and building the 

eventual space station. All potential emergencies during ascent were covered by “intact 

abort” scenarios in which the orbiter flew to a 

recovery site and landed, eliminating the need 

for any personal-protection devices, such as 

ejection seats or pressure suits. For emergencies 

on orbit, NASA investigated concepts such as 

“rescue balls” in which crewmembers cocooned 

themselves in inflatable enclosures, and the 

crew from another space shuttle pushed them 

Most early shuttle concepts 

showed a fully reusable, 

two-stage vehicle. At the 

time, NASA and its contractors were enthralled with the 

idea that somehow, the space 

shuttle would operate much 

as a commercial airliner, 

and there were no immediate plans to use pressure 

suits, except for extravehicular activities (EVA).

NASA
366

Prior to the first space shuttle mission, NASA investigated the 

concept of a “rescue ball” that an astronaut could take refuge 

in. Astronauts could carry the balls from the stricken vehicle 

to a nearby rescue vehicle. The concept was investigated again 

after the Challenger accident in 1986.

NASA

the short distance between the stricken vehicle 

and the rescue ship. It appears that the pros-

pect of an emergency during entry, despite 

the red-hot temperatures as the vehicle slowed 

from 17,500 mph to landing speed, was sim-

ply dismissed as improbable.

ISSA AND EIS—STILLBORN SPACE 

SHUTTLE SUITS 

By late 1970, NASA was 2 years into the formal space shuttle study cycle and was beginning to better define details, such as the need 

for pressure suits. Although the orbiter would 

have a shirtsleeve environment, pressure suits 

would still be needed if the cabin depressurized due to a leak or systems failure. To 

define exactly why an astronaut would need 

a suit, engineers at the Manned Spacecraft 

Center (MSC, later renamed the Lyndon B. 

Johnson Space Center, or JSC) conducted an 

internal study of possible pressure suit requirements. To further investigate the type of suit 

needed to counter these emergencies, the 

MSC funded Space Age Control, Inc. and the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

367

International Latex Corporation—the primary 

spacesuit contractor on Apollo—to develop 

prototypes of representative pressure suits.

On October 1, 1970, MSC awarded an 

18-month contract to Space Age Control in 

Palmdale, CA, for the fabrication of two Intravehicular Space Suit Assembly (ISSA) prototypes. Space Age Control had been established 

in 1968 to design, develop, and manufacture 

pilot-protection devices for space-based and 

high-performance aircraft test programs. In 

1970, NASA awarded the company a contract 

to produce precision, small-format position 

transducers for aircraft flight-control testing. 

The success of this effort led to the development of a complete line of position transducers 

that were used by more than 900 customers in 

20 industries around the world.2

The NASA contract called for developing 

a flexible, comfortable pressure suit capable 

of operating at 5 psi (versus 3.5 psi for most 

aviation pressure suits) that weighed less 

than 12 pounds. The Space Shuttle Program 

wanted a pressure suit that would satisfy the 

requirements of launch, vehicle transfer, entry, 

pressurized and unpressurized cabin operation, and possible emergency operations. The 

effort was divided into three phases. Phase A 

included configuration analysis and detailed 

design, Phase B fabricated a prototype based 

on the Phase A design, and Phase C fabricated 

a second prototype based on the results of 

testing the first suit. Space Age delivered the 

Phase C suit to MSC on March 9, 1972.3

One of the primary concerns of any pressure 

suit designer is shoulder mobility, and by 

1970, the only mostly satisfactory arrangement was the one developed by David Clark 

Company using Link-Net. Since this was proprietary technology, Space Age Control wanted 

to find another solution. In the past, designers 

of soft- and hard-suit shoulder joints had tried 

pleated convolutes, molded convolutes, rotating bearings, ball and socket fittings, rolling 

convolutes, mechanical hinges, and stovepipe 

sections in an attempt to provide mobility. 

None of these had attained the nude range of 

shoulder motion in all planes, although LinkNet had come closest. Space Age investigated 

two designs: a preshaped sewn convolute and a 

single-axis random convolute.

The preshaped joint consisted of two cone 

frustums sewn together at the shoulder joint 

using convolutes that were 7.0 inches inside 

diameter and 8.80 inches outside diameter. 

Space Age discovered that a difficulty with 

this type of joint was designing a restraint 

system that had low friction when sliding 

through the turnarounds. Numerous systems 

were tested, and Dacron cord and stainless 

steel turnarounds proved the most promising. 

Space Age fitted its Phase B suit with a sewn 

convolute shoulder joint. The problems that 

surfaced during testing were frictional wear of 

the restraint slip cords and noise as the cords 

slid through the turnarounds. In addition, the 

bulk of the joint made it impossible to meet 

the 23-inch shoulder measurement specified 

in the contract.

As an alternative, Space Age investigated a 

single-axis, random convolute joint. This 

joint had a restricted range of motion in the 

transverse plane (adduction-abduction) but 

excellent torque characteristics in the lateral 

medial plane. It also solved the frictional wear 

and noise problems and fit within the required 

shoulder width. This joint was formed by 

restraint cords located on each side of a cylinder of nylon restraint material that was 

gathered by pleating along the restraint line. 

A restraint cord was stitched over the pleats to 

hold them in place. Space Age installed this 

shoulder on the Phase B suit, and other than 

the expected lack of motion in the transverse 

plane, it was more comfortable, had a better 

arms-down profile, had lower torque, and was 

cycled 5,000 times without failure. Space Age 

selected this design for the Phase C suit. 

To eliminate an adjustable frontal tiedown system for sitting or standing configurations, the 

Space Age designers incorporated a waist gusset. The first design consisted of nylon passthroughs and nylon cord similar to the takeup 

used on NASA pressure boots. This design 

exhibited adequate strength, but the positive 

locking of the cord ends was bulky, and it was 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

368

difficult to open the gusset due to the close 

tolerance necessary between the nylon passthroughs when closed.

The second design used a Talon eight-chain 

brass zipper on nylon tape. Structurally, either 

of the designs was adequate, but the second 

design required less room to install on the suit 

and Space Age used the eight-chain zipper 

for the Phase C suit. The takeup along the 

torso centerline was 5.5 inches, which allowed 

full standing with no encumbrance with the 

zipper opened and foreshortened the frontal 

section sufficiently when closed to maintain 

the correct helmet position at 5 psi.

The preliminary Space Age head covering 

used a full-hemisphere visor bonded to 

the basic pressure garment. The Phase B 

helmet, with a diameter of 12 inches, was 

considerably larger than necessary and 

presented a storage problem. The Phase C 

helmet was reduced to 10.25 inches wide 

and 12 inches deep.

Space Age investigated two glove-disconnect 

designs. The first approach was a metal 

disconnect, designed so the outer housing 

functioned as a spring clamp. Although having safety features that appeared complex, the 

designs operation was simple, requiring only 

opposing forces from the thumb and forefinger to open when the suit was unpressurized. 

Before donning the suit, the wearer moved 

the latch to the closed position, depressed the 

latch lock pin, and moved the latch outward 

to the armed position. Engagement of the 

suit-glove connector automatically brought 

the connector to the lock-lock position. Space 

Age used this system in the Phase B and 

Phase C suits.

Space Age also investigated a soft-roll sealglove disconnect to further reduce weight and 

increase comfort. This disconnect consisted 

of a neoprene tube on both the glove and 

suit. The suit seal was folded upward over the 

forearm and the glove seal was pulled over 

the suit seal. The seal ends were then rolled 

or folded downward to create the seal, similar 

to the original waist seal on the David Clark 

MC-2 suit. This design proved comfortable 

and reliable at the required suit pressures, but 

it increased donning time, required greater 

dexterity for donning, and increased leakage.

Space Age fabricated the gas bladders for both 

suits from neoprene-coated nylon ripstop 

fabric covered by a nylon restraint layer. The 

Phase B suit, including gloves, communications carrier, and bioinstrumentation connector, weighed 13 pounds and 3 ounces. The 

basic Phase C suit was over a pound lighter, 

but the gloves were somewhat heavier, resulting 

in a total weight of 12 pounds and 1.5 ounces, 

very slightly over the requirement. Space Age 

noted it could reduce the weight of the Phase 

C if the pockets were eliminated but decided 

During the definition phase for the Space Shuttle, engineers 

expected the crew to operate in a shirtsleeve environment 

throughout the mission. Eventually the program acknowledged that pressure suits would still be needed if the cabin 

depressurized due to a leak or systems failure. In 1970, NASA 

awarded contracts for the development of a lightweight, Intravehicular Space Suit Assembly (ISSA) that could be stored in 

lockers in the crew compartment. One of these contracts went 

to Space Age Controls in Palmdale, CA. This Phase C suit 

used a smaller helmet than the earlier Phase B suit.

Courtesy Space Age Control, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

369

the pockets were functional and elected to 

keep them.4

During predelivery testing, Space Age pressurized the Phase C suit to 5 psi for 15 minutes, 

with a leak rate of 240 cc per minute, within 

the specification. The suit was then pressurized to 8 psi for 15 minutes and returned 

to 5 psi with the leak rate still 240 cc per 

minute. Several subjects demonstrated the 

suit could be self donned with relative ease. 

A subject dressed in long underwear could 

take the suit out of its storage container, don 

it, and attach the gloves in 6 minutes. If the 

gloves were already mated to the wrist rings, 

the time was reduced to 3 minutes and 5 seconds. In all cases, the suit could be doffed in 

less than a minute. Mobility was satisfactory, 

although the shoulder did not meet the rangeof-motion requirements. Space Age believed 

it had a revised shoulder—consisting of two 

single-axis joints offset 90 degrees to each 

other and joined by a low-profile rigid-bearing 

coupler—that would satisfy the requirement. 

Ultimately, Space Age concluded:

Significant advances were accomplished 

in manufacturing a lightweight, comfortable, highly articulate full-pressure suit 

that is capable of withstanding a pressure 

differential of 5 psi. Of major importance 

is the simple elbow and knee joints that 

exhibit very low torque and excellent neutral range of motion. No cable restraints 

or metal turnarounds were required on 

the suit to maintain stability or structural 

integrity. There is a need for substantial 

improvement in glove disconnects for this 

type of suit to meet the requirements of 

rapid donning. If it is decided that a flexible, stowable visor is required for future 

suits, additional design effort is required 

to provide a better material than the vinyl 

used for these suits. The shoulder joints 

resulting from this program do not meet 

the operational requirements of a flight 

vehicle due to the limited transversemotion capability. It is our opinion that a 

shoulder joint, using the basic single-axis 

design, can be developed using a slip ring 

turnaround separating 2 single-axis joints, 

or a slip ring at the armhole opening and 

2 single-axis joints (offset 90 degrees) 

separated by a fixed load-carrying ring 

and perhaps an upper arm bearing. In 

order to prevent over-design of a shoulder 

joint, detail cockpit motion envelope 

requirements should be stipulated prior 

to design effort.5

A 1970 ILC advertisement boasted, “The 

ability to move is the secret that keeps ILC 

ahead of its competition and the ISSA Suit 

(Intravehicular Space Suit Assembly) is real 

proof of that fact. Hardware speaks louder 

than words.”6 The hardware being referred to 

was a company-funded 1969–70 prototype 

of a lightweight “Briefcase Suit” that offered 

compact stowage. ILC considered the suit’s 

technology mature since many of its ideas, and 

even some of its components, were directly 

traceable to the Apollo A7L spacesuits.

MSC awarded the second contract for a prototype ISSA to International Latex Corporation in Dover, DE (ILC Dover), on October 

8, 1970. By this time, Dixie Rinehart, John 

Ratermanis, Al Kenneway, George Matthews, 

and George Durney in the Soft Goods Engineering Group at ILC had already completed 

the design using corporate funding. The 

As required, the ILC Dover ISSA concept fit into a small 

suitcase; the storage space could be halved if the suit was 

vacuum packed. Oddly, engineers at ILC had already 

investigated the idea of a suitcase spacesuit as part of a 

company-funded study during 1969–70.

Courtesy of the International Latex Corporation
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

370

In an emergency, an astronaut could quickly self don the ILC 

ISSA suit. Although called an IVA suit, it could be used for 

limited EVA activities if needed (mostly meaning an ability 

to move from a damaged orbiter to a rescue vehicle).

Courtesy of the International Latex Corporation

Considering the suit could be stored in a 0.5-cubic-foot 

suitcase, it looked very bulky in use. Like its Space Age 

Control counterpart, this suit was pressurized to 5 psi 

instead of the normal 3.5 psi but was still fairly flexible.

Courtesy of the International Latex Corporation

designers largely based their ISSA largely on 

the Briefcase Suit developed earlier that year. 

The Phase B prototype weighed 10.2 pounds, 

including the suit, two arm bearings, gloves, 

boots, and soft helmet with integral visor. 

The garment measured 22.75 inches across 

the shoulders and 16.75 inches across the 

knees. The suit could be stored in a volume 

of 0.5 cubic foot, which could be reduced to 

0.22 cubic foot if the garment was vacuum 

packed. The pressurized mobility was equal 

to or greater than the Apollo suit, and the 

unpressurized mobility was somewhat greater. 

ILC fabricated a second suit that featured a 

flat-pattern mobility system aimed at further 

reducing storage volume and cost and improving mobility. The Phase C suit was delivered to 

MSC in May 1971.7

NASA researchers and astronauts at MSC 

evaluated the Space Age and ILC suits for 

several months, but no record of the results 

could be located. In any case, neither suit 

would be produced or flown.

As the ISSA suits were being evaluated, external 

events caused NASA to reconsider its position 

concerning pressure suits in the space shuttle 

during ascent and entry. On June 30, 1971, 

the Soyuz 11 spacecraft prepared to enter 

the atmosphere after a 2-week visit with the 

Salyut 1 space station. Unknown to the crew 

or ground controllers, a ventilation valve 

between the orbital module and the descent 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

371

module failed during retrofire. Somewhere 

above 100 miles altitude, as the descent 

module entered the atmosphere, the failed 

valve opened, allowing the vehicle to depressurize. As built, the three-man Soyuz was 

not large enough to accommodate a crew 

wearing pressure suits, and the crew of 

Soyuz 11—Vladislav Nikolayevich Volkov, 

Georgiy Timofeyevich Dobrovolskiy, and 

Viktor Ivanovich Patsayev—died from asphyxiation within seconds. After the accident, the 

Soviets redesigned the Soyuz spacecraft to 

accommodate only two crewmembers, this 

time wearing spacesuits. It would not be until 

the introduction of the Soyuz T variant in 

1980 that the capsule accommodated three 

crewmembers in spacesuits.8

The concern went beyond the need for 

pressure suits, but it also included what 

type of pressure suit would be most useful. 

Aviation pressure suits, and the ISSA prototype 

from ILC Dover, typically operate at about 

3.5 psi, using pure oxygen as a breathing gas 

(the Space Age ISSA prototype operated at 

5.0 psi). NASA physiologists worried this 

might not be sufficient pressure to save a crew 

in a Soyuz-type accident since there would 

be no time to prebreathe pure oxygen to 

prevent decompression sickness. Researchers 

were beginning to think that a high-pressure 

suit, perhaps using as much as 8 psi, would 

be necessary to protect the crew. At the same 

time, physiologists began wondering if there 

was a better way to conduct EVA—the limited 

experience on Gemini and Apollo had not 

answered many questions, and NASA expected 

many thousands of EVA hours would be 

needed to construct the eventual Space Station.

To validate its proposed requirements, 

NASA embarked on a yearlong effort to 

study intra-vehicular activity (IVA) and EVA 

tasks, guidelines, and constraints, as well as 

to develop requirements for pressure suits, 

mobility aids, and emergency intervehicular 

transfer support.9

 To support the effort, on 

March 14, 1972, NASA awarded a contract 

to the Hamilton Standard Division of 

United Aircraft Corporation and 2 weeks 

later awarded a contract to the Vought 

Systems Division of LTV Aerospace and its 

subcontractors Convair, ILC Dover, and 

Rockwell International.10 Hamilton Standard 

concentrated on the environmental and lifesupport system aspects of the issue, while the 

Vought team defined the suits themselves. 

The Hamilton Standard and Vought studies 

concentrated on the EVA aspects of the 

program since that was the larger unknown. 

Nevertheless, the effort examined what sort of 

protection the crew and passengers would need 

in the event of a cabin pressurization failure 

or a systems failure that forced the vehicle to 

remain on orbit awaiting rescue.11

Vought subcontracted much of the actual 

suit study to ILC Dover, which delivered 

its report to Vought in December 1972. 

The requirements for an IVA suit, as seen 

by ILC, included allowing the commander 

and pilot to control the orbiter during 

entry and landing, allowing the crew to 

assist EVA crewmen into the orbiter in the 

event of an airlock failure, and performing 

limited contingency EVAs in the event of an 

emergency (i.e., transfer to a rescue vehicle). 

Oddly, given they had already designed the 

ISSA prototype under a different contract, 

the engineers at ILC initially believed these 

requirements could be met by using the 

existing Apollo A7LB suits. It soon became 

obvious this was not the case.12

After a great deal of study regarding the 

possible scenarios that would force a crew 

to don suits, ILC validated NASA’s concerns 

and selected an 8 psi operating pressure 

since this eliminated the need to prebreathe 

pure oxygen. The suit would have a proof 

pressure of 16 psi and a burst pressure of 

20 psi, providing an adequate margin of safety. 

Having decided upon this high-pressure suit, 

ILC evaluated the A7LB suit and determined 

the mobility of the shoulder, hip, and waist 

joints became impractical above 6 psi. The 

ILC engineers believed they understood the 

problems and could fabricate joints that 

would provide acceptable mobility at the 

higher pressures. However, the gloves seemed 

to present an unsolvable problem. Fortunately, 

researchers at the NASA Ames Research 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

372

Center were already working with several 

contractors to develop gloves that would 

operate at 8 psi, so ILC did not dwell on 

the issue. In addition, ILC determined 

that the leakage rates of the A7L series 

suits made them unacceptable for use as 

emergency garments.13

ILC pointed out that an 8-psi suit would 

have a larger stowage volume than lower 

pressure suits, although making a twopiece suit that separated at the waist, with 

a detachable helmet and gloves, could 

lower these requirements somewhat. The 

report investigated ventilation, cooling, 

and pressurization requirements, as well as 

donning-and-doffing considerations. The 

engineers also presented a detailed evaluation 

on the required impact, thermal, and radiation 

protection.14 Vought expanded the ILC report 

considerably before delivering to NASA in 

April 1973. The final recommendation was 

for a new IVA suit that used incremental 

sizing (like aviation pressure suits, and unlike 

the custom-fitted A7LB suits), a hard waist 

connector for donning and doffing, and a 

soft helmet. A thermal overcoat could provide 

short-term impact and thermal and radiation 

protection for contingency EVAs. A simplified 

version of the suit that provided less mobility 

by deleting the bearings at the shoulders, 

neck, elbows, and wrists could suffice for 

passengers that needed life support but had 

no duties other than staying alive.15

Hamilton Standard came to generally the 

same conclusions as Vought-ILC regarding 

IVA requirements. However, Hamilton 

Standard did not attempt to design a 

pressure suit, concentrating instead on its 

area of specialty: the environmental and 

life-support systems. Nevertheless, its report 

recommended a lightweight suit that could 

be donned quickly in the event of the loss 

of cabin pressure. Unrealistically, the study 

determined that a trained crewmember 

should be able to don and activate a pressure 

suit within 1 minute. Each suit should 

The ILC Dover Emergency Intravehicular Suit (EIS) operated at 8 psi to support reasonably rapid decompression from 

a 14.7-psi cabin pressure without risk of decompression 

sickness. The entire suit, except for the waist disconnect ring, 

was fabricated of flexible materials, including the helmet 

and face shield.

Courtesy of the International Latex Corporation
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

373

ILC Dover evaluated the EIS prototype using a side-stick 

controller being proposed by the North American Aviation 

Space Shuttle team. Like the ISSA concept, the EIS would 

only be used in an emergency, but pilots would still be 

required to fly and land the vehicle.

Courtesy of the International Latex Corporation

include a portable breathing system capable 

of supporting the crewmember for 1 hour, 

and onboard systems should be capable 

of supporting all 10 crewmembers for 

10 hours for mission aborts and 96 hours 

while awaiting on-orbit rescue.16

While those studies were ongoing (and 

perhaps one reason ILC did not bid on the 

studies as a prime), in 1972 NASA awarded 

ILC a contract to fabricate an emergency 

IVA prototype that looked a lot like the suit 

concept it provided to Vought for its report. 

The Emergency Intravehicular Suit (EIS) 

operated at 8 psi to support reasonably rapid 

decompression from a 14.7-psi cabin pressure 

without risk of decompression sickness. The 

21-pound EIS was entirely soft, except for 

a circular waist entry disconnect, helmet 

disconnect, and arm bearings. Tailoring was 

by laced and zipper takeups on the restraint 

garments. The fabric helmet used an integral 

acrylic bubble.17

All of the suit manufacturers pointed out the 

need for better gloves. In response, the NASA 

Ames Research Center awarded contracts to, 

at least, David Clark Company, ILC Dover, 

Space Age Control, and the Aerotherm 

Division of Acurex Corporation in Mountain 

View, CA. Some of these contracts directed 

research toward gloves that could satisfactorily 

operate at 5 psi, while others investigated 8-psi 

gloves. Most of this research was oriented 

toward EVA gloves, but some was applicable 

to an IVA suit as well.

For instance, William Elkins headed a 

7-month effort at Aerotherm that included 

developing a new layup technique for a 

miniconvolute joint system and evaluating 

its effectiveness at 8 psi pressure. Eventually, 

he proved the joints could safely withstand 

100,000 cycles. The final Aerotherm 

glove used a 3-ply layup of marquisette 

cloth and neoprene that resulted in a 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

374

NASA astronaut Robert L. “Crip” Crippen in the cockpit 

of Columbia (OV-102) on October 10, 1980, prior to the 

launch of STS-1. Note the modified Lockheed SR-71 ejection 

seat and Crip’s David Clark Company S1030A full-pressure 

Ejection Escape Suit. Columbia was the only space-rated 

Orbiter to use ejection seats, and they were only active for the 

four orbital flight test (OFT) missions (although they were 

physically installed until after STS-9).

NASA

0.017-inch thick glove. The miniconvolute 

joints were inlaid only on the back side of the 

fingers, leaving a smooth front surface that 

presented more feel and was less vulnerable 

to snagging. The palm area was reinforced 

with a stainless steel and Nomex cloth. 

Subsequent phases of the effort, completed at 

the end of 1974, concentrated exclusively on 

EVA requirements.18

As the Space Shuttle morphed through its 

development phase, NASA continued to 

emphasize the relative safety of airline-type 

operations. In addition, cost and schedule 

were becoming major concerns, and NASA 

returned to its original concept of a shirtsleeve 

environment for the Space Shuttle. 

S1030A—EJECTION ESCAPE SYSTEM 

(EES) SUITS 

Long prior to the first flight of Columbia 

(OV-102), NASA engineers decided that 

the Space Shuttle would not have an 

escape system. Simulations showed that the 

Space Shuttle system was safe, and in the 

unlikely event that something did go wrong, 

the best option was an “intact abort” where 

the orbiter separated from the stack and flew 

to a conventional runway landing at some 

predetermined location. This philosophy was 

similar to that used for airliners, which do not 

provide parachutes or ejection seats for passengers or crew. However, NASA was well aware 

that the test flights posed an unreasonable 

danger to the two-person crew and took steps 

to mitigate the risks.

The crews for the eight Approach and 

Landing Test flights that used Enterprise (OV101) at Edwards AFB during 1977 did not use 

pressure suits since the maximum altitude of 

the flights was just over 30,000 feet. However, 

they did sit on modified SR-71 ejection seats. 

These seats were the highest performance 

ejection seats in the operational inventory 

at that time (the hypersonic X-15 research 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

375

The David Clark Company S1030A was a derivative of the 

S1030 suits used on the Air Force SR-71 program. Most of 

the hardware was identical to the S1030 and, in fact, was 

borrowed from the Air Force. However, the softgoods were an 

all-new design to meet Space Shuttle Program requirements.

NASA

airplane had used higher performance seats, 

but the program had been out of business for 

a decade, and the seats were unavailable and 

overly complex in any case).19

After Enterprise proved the orbiter could 

glide to a controllable landing, the next step 

was to test an orbiter in space. There would 

be no unmanned test flights, and John 

W. Young and Robert L. “Crip” Crippen 

became the first crew to fly a new vehicle 

on its maiden space flight. Between April 

1981 and July 1982, Columbia (OV-102) 

conducted four Orbital Flight Tests (OFT). 

Like Enterprise, Columbia was equipped 

with modified SR-71 ejection seats for its two 

pilots. Each crewmember wore David Clark 

Company S1030A full-pressure suits. These 

were variants of the Air Force S1030 Pilots 

Protective Assembly used by SR-71 crews and 

provided proven protection up to Mach 2.7 

and 80,000 feet.20

Separately, on November 15, 1976, NASA 

awarded David Clark Company (DCC) a 

$98,171 contract to develop an Anti-G Suit 

(AGS) for the OFT flights. James D. Schlosser 

at JSC was the contract monitor, and Jack 

Bassick was the David Clark Company project 

engineer. Although the ascent acceleration 

was relatively benign, the entry environment 

was less well understood, so acceleration 

protection might be needed. NASA expected 

to use the AGS to apply counter-pressure to 

the abdomen, thigh, and calves. The crewmembers wore the 3-pound AGS under the 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

376

Ejection Escape Suit (EES) and donned it 

through slide fasteners on each leg and the 

side of the abdomen. Heat-sealed urethane 

bladders were covered with an oxford-nylon 

restraint that had lace adjustments at the 

waist, thighs, and lower legs. An Anti-G 

Control Valve (AGCV) was integrated on 

the left thigh of the full-pressure suit, and a 

relief valve vented the bladders if the pressure 

exceeded 3.0 psig. The AGCV was manually 

adjustable to provide between 0 and 2.5 psi. 

The AGCV was designed to automatically 

vent the AGS when the full-pressure suit pressurized and shut off in the event of a continuous flow (e.g., a leak in the AGS). Carleton 

Controls provided the AGCV.21

NASA issued David Clark Company a 

second contract on August 7, 1978, to 

develop the S1030A full-pressure suits. 

Joe Ruseckas at David Clark Company 

originally estimated the development effort 

and fabrication of a dozen suits would cost 

$325,845, not including the Governmentfurnished hardware that would come from 

the SR-71 program. Eventually, largely 

because of constantly changing requirements 

as the Space Shuttle Program matured, the 

13 suits cost $578,304, exclusive of the 

hardware supplied by the USAF. NASA 

called the S1030A an EES.22

Contrary to most reports, the dozen S1030As 

were not “modifications” of Air Force S1030 

suits but were new suits fabricated expressly for 

the Space Shuttle Program. They were derivatives of the S1030 design, using most of the 

same hardware and manufacturing techniques. 

However, although the softgoods were based 

on S1030 experience, they were necessarily 

different to support the addition of the AGS 

and biomedical instrumentation port and to 

increase the proof-pressure requirements. 

The S1030A consisted of a pressure suit, 

helmet, gloves, exterior cover, AGS, and 

biomedical instrumentation system. The 

breathing space was separated from the rest 

Table 9—S1030A Ejection Escape Suits

Serial 

Number Size Color Astronaut Mission

001 Large-Long Gold Fypro Certification Suit —

002 Medium-Regular Dark Gold PBI John W. Young STS-1

003 Medium-Regular Dark Gold PBI Robert L. “Crip” Crippen STS-1

004 Medium-Long Dark Gold PBI Joe H. Engle STS-2

005 Medium-Regular Dark Gold PBI Richard H. Truly STS-3

006 Large-Long Dark Gold PBI Jack R. Lousma STS-3

007 Medium-Regular Gold Fypro Fred W. Haise, Jr. —

008 Large-Regular Gold Fypro Vance D. Brand —

009 Medium-Long Dark Gold PBI Charles Gordon “Gordo” 

Fullerton

STS-3

010 Short-Long Dark Gold PBI Thomas K. “Ken” 

Mattingly

STS-4

011 Large-Regular Gold Fypro Paul J. Weitz —

012 Medium-Long Dark Gold PBI Henry W. “Hank” 

Hartsfield, Jr.

STS-4

013 Large-Long Gold Fypro Robert F. Overmyer —

Source: NASA S1030A Ejection Escape Suit (EES), 

a serial number list supplied by David Clark Company.
377

The STS-003 crew, Jack R. Lousma (left) and C. Gordon 

Fullerton, show off their S1030A suits on January 20, 1982. 

These were both dark gold PBI suits.

NASA

of the suit by a face seal. A dual-demand 

breathing regulator mounted in the helmet 

automatically delivered breathing oxygen 

when the wearer lowered the helmet visor. 

The ventilation connector was located on the 

lower left of the torso and the AGCV was 

located on the left thigh.23

Another difference was that NASA wanted 

the helmet microphones to always be “hot” so 

that the pilots did not have to key a transmit 

switch when they talked and all events could 

be recorded on the ground. As anybody who 

has listened to conversations with people using 

breathing devices on a “hot mic” can attest, 

it is very distracting when the wearer inhales. 

David Clark Company solved this by installing 

microphone cutout switches in the S1030A 

helmet. These switches were tied to the oxy-

gen regulator such that every time the pilot 

inhaled, the switches muted the microphone.24

The proof pressure requirements for 

Space Shuttle differed somewhat from the 

SR-71. On the Blackbird (and U-2R), the 

cockpit was nominally pressurized to the 

equivalent of 35,000 feet during routine 

operations, meaning there was about 3.5 psi 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

378

pressure on the suit. If the cockpit explosively 

depressurized, the suit-pressure controller 

closed and the suit immediately inflated to 

3.5 psi, so there was little pressure transient. 

In the orbiter, the cabin was maintained at 

14.7 psi. If the cabin explosively depressurized 

and the suits inflated to 3.5 psi, there was an 

11.7-psi transient, and NASA wanted to verify 

the suit could tolerate the stress. No problems 

were noted during the tests.

On October 27, 1978, James V. Correale, 

the chief of the Crew Systems Division at 

JSC, wrote to Lt. Col. Calvin E. Greer in 

the SR-71 Program Office at Norton AFB, 

CA, requesting 13 sets of S1030 hardware 

be supplied to David Clark Company to 

facilitate the manufacture of the EES suits. 

This hardware included pressure controls, 

neck rings, wrist rings, ventilation fittings, 

helmets, and miscellaneous fittings. This 

transfer of SR-71 hardware had been 

previously coordinated with Tom Bowen 

from the Physiological Support Division 

at Beale AFB. Greer concurred with the 

request on November 17, and the Air Force 

released the hardware shortly thereafter.25

David Clark Company fabricated the suits 

during March 1979 in five sizes to fit the 

12 astronauts assigned to the OFT flights. 

Interestingly, five of the suits used gold Fypro 

covers and eights used functionally identical 

dark-gold Polybenzimidazole (PBI) covers.26

As seen before the first flight, NASA expected 

the OFT to consist of six missions, but 

political expedience later dictated they 

would end after the fourth mission, despite 

not fulfilling all of their original objectives. 

Since the operational flights would have 

more than two crewmembers, the ejection 

seats in Columbia were deactivated after 

STS-4, although they would not be physically 

removed until a modification period that 

took place following STS-9. Five of the 

S1030A suits were sent to Beale AFB, where 

the PSD recovered the hardware for use on 

standard S1030 PPAs. NASA removed the 

USAF hardware from the remainder of the 

suits and they were subsequently scrapped, 

as were the ejection seats.27

LEH—LAUNCH ENTRY HELMET

NASA believed that all of the crew should have 

“equal access” to escape; therefore, if the astronauts on the middeck could not have ejection 

seats, then nobody would. It was a contentious 

argument in the astronaut office but one that 

ultimately concluded there would be no escape 

provisions for the operational flights.28

Beginning with STS-5, the first “operational” 

mission, Space Shuttle crews wore tailored 

“NASA blue” flight suits, an AGS, and a 

derivative of an off-the-shelf helmet during 

launch and entry. The AGS was a cutaway 

suit made by the David Clark Company based 

on the standardized USAF G-suit and was 

generally similar to the AGS used under the 

S1030A suits during the OFT.29

The Launch Entry Helmet (LEH) was donned 

via an unusual “clamshell” hinging mechanism that divided the helmet into joinable 

fore-and-aft, semi-hemispherical sections. 

The flight suit and helmet were supplemented 

by an inflatable life vest, harness assembly, 

jump boots, and gloves. The entire ensemble 

weighed about 21.2 pounds. The LEH helmet 

was distantly related to the AOH-1 (Aviator 

Oxygen Helmet) developed by Protection, Inc. 

for the Navy. The integrated oxygen breathing and bump-protection helmet provided 

a breathing space using a face seal instead of 

using a conventional oronasal mask. The aft 

portion of the helmet was open to ambient air. 

The resulting helmet, perhaps unsurprisingly, 

looked much like a full-pressure suit helmet, 

but it was not.30

The AOH-1 led to the Air Force HGU-15/P 

helmet developed during the early 1960s 

for pilots of the Convair F-106 Delta Dart 

interceptor as an alternative to wearing fullpressure suits. The Air Force wanted the 

helmet to provide head protection during 

high-speed ejections and have an integrated 

pressure-breathing mask, along with visors 

that protected against severe sunlight at high 

altitudes and flashes from the nuclear-tipped 

Falcon missiles. The Air Force purchased 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

379

A Shuttle crew wearing the 

standard flight suits and 

LEH helmets in a simulator 

at the Johnson Space Center. 

Each orbiter had eight 

connections that supplied 

100-psi oxygen for the LEH 

regulators and Anti-G Suits. 

At this point, there was no 

intent to wear pressure suits 

in the orbiter.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

380

Reportedly, the chief of the astronaut office, John W. Young, 

thought the initial all-white LEHs were too plain and 

requested Gentex to develop a more suitable paint scheme. 

All of the production helmets used pearlescent white paint 

with red and blue stripes and both the NASA “worm” and 

“meatball” logos. The ratchet knob on the right side of the 

helmet allowed the wearer to adjust the face seal.

Courtesy of Gentex Corp.

16 HGU-15/P helmets from Protection, Inc. 

for operational evaluation using Lockheed 

F-104 Starfighters and Republic F-105 

Thunderchiefs at George AFB, CA. The 

pilots quickly complained that the faceplate 

visor severely limited peripheral vision and 

that, at 8 pounds, the helmet was too heavy. 

The Air Force discontinued the project in 

early 1964.31

The design was revived in 1968 when the 

Navy purchased more than 700 similar 

HGU-20/P helmets and issued them to 

fighter squadrons for operational testing. By 

this time, Gentex Corporation had purchased 

Protection, Inc. The Navy pilots had many 

of the same complaints as their Air Force 

counterparts and the Navy quickly withdrew 

the helmet from use.32 Despite its failure as 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

381

As late as 2010, some LEH helmets were still being used 

during training exercises with S1032/S1035 suits, where they 

adequately simulated the weight and mass of a full-pressure 

helmet. These were undoubtedly some of the last items that 

still used the NASA logotype (worm) that was retired from 

official use in 1992. 

NASA

a military helmet, the clamshell design has 

been used in many nonaviation applications, 

most notably for chemical protection suits.

During the late 1970s, NASA physiologists 

decided a clamshell helmet was a reasonable 

compromise between a shirtsleeve environment and a pressure suit. Given the short 

time before Space Shuttle flights were 

scheduled to begin and the limited funding 

available, James D. Schlosser at JSC sought 

an existing design upon which to base the 

helmet. Enter the HGU-20. Gentex took 

the basic HGU-20 concept and modified it 

to meet NASA specifications. This included 

using nickel instead of cadmium-plated hardware, adding a second microphone, and adding a microphone-breathing cutout. Gentex 

developed a new oxygen regulator to meet 

the NASA flow characteristics, a constantly 

changing target since NASA kept revising the 

specification. To improve comfort, new takeup reels, using a ratchet knob on the right side 

of the helmet, kept the face seal tight against 

the wearer. The neoprene face seal was adjustable for various face sizes and shapes, although 

some astronauts still needed to be custom 

fitted. Similarly, a variety of cushion pads 

were provided for inside the helmet, but 

several astronauts needed custom pads to 

achieve the desired comfort and protection. 

Three sizes of back shells were available: 

small, regular, and extra large.33

Given that the astronauts did not wear any 

counter-pressure clothing, the LEH could not 

function as a pressure-breathing mask (at least 

not under any meaningful pressure) and since 

there were no contingency plans to bail out of 

the orbiter (and indeed, no parachutes), the 

helmet did not provide windblast protection. 

In reality, the only protection the helmet 

provided was against ambient noise during 

ascent, incidental bumping of the head against 

the inside of the crew module, and possible 

smoke in the cockpit.

Gentex began fabricating LEH helmets in 

early 1981 and delivered about 20 helmets 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

382

per year through 1985. An order for an 

additional 20 was in place prior to the 

Challenger accident, and Gentex delivered 

10 helmets from this order before terminating 

production. The initial batch of helmets 

were standard USAF white, but John W. 

Young, the chief of the astronaut office 

(and commander of STS-1), did not believe 

the appearance of the helmet properly 

represented NASA. Subsequent helmets were 

painted pearlescent white with red and blue 

stripes and strategically placed NASA logos. 

Reportedly, Gentex manufactured a pink 

LEH for an unidentified female astronaut, 

although it was never worn for an actual 

mission (if at all).34

Each orbiter was equipped with eight oxygen outlets (four on the flight deck and four 

on the middeck) that supplied 100-psi for 

the LEH regulators and AGS. After NASA 

replaced the LEH helmets with the S1032 

LES and, later, the S1035 ACES ensembles, 

the controllers remained labeled “LEH”. In 

addition to working with the later pressure 

suits, the control panels could be used with 

the emergency “Quick-Don Mask” assemblies 

that were carried aboard the orbiter for emergency use during on-orbit operations and for 

EVA prebreathing.35 As late as 2011, some 

LEH helmets were still being used during 

training exercises, where they adequately simulated the weight and mass of a full-pressure 

suit helmet.

S1032—LAUNCH ENTRY SUITS (LES)

A cold morning dawned in central Florida on 

January 28, 1986, as a crew of seven boarded 

the Challenger (OV-099) for the first flight 

from the newly completed Launch Complex 

39B at the Kennedy Space Center. The program was picking up momentum; this was the 

25th Space Shuttle launch and the eleventh in 

the past 12 months. A significant amount of 

ice had accumulated on the launch pad overnight, creating considerable concern for the 

ground operations team, which delayed launch 

several hours to allow the ice to melt. At 11:15, 

the team gave a “go” for launch despite the 

ambient air temperature being only 36 oF measured at ground level approximately 1,000 feet 

from the vehicle. This was 15 degrees colder 

than any previous Space Shuttle launch.

The final flight of Challenger began at 

11:38:00.010, Eastern Standard Time. 

Seventy-three seconds later, the Flight 

Dynamic Officer in the Mission Control 

Room in Houston announced, “... RSO [the 

USAF range safety officer] reports the vehicle 

has exploded.”36 Francis R. Scobee, Michael J. 

Smith, Judith A. Resnik, Ellison S. Onizuka, 

Ronald E. McNair, Gregory B. Jarvis, and 

Sharon Christa McAuliffe were killed.

President Ronald Reagan established a 

Presidential Commission chaired by former 

Secretary of State William P. Rogers to 

investigate the accident. The 14-person 

commission included such notables as Neil A. 

Armstrong; 1965 Nobel Laureate in physics 

Richard P. Feynman; and the first U.S. woman 

astronaut, Sally K. Ride. The commission 

released its report on June 6, 1986.

The consensus of the Commission and 

participating investigative agencies is 

that the loss of the Space Shuttle Challenger was caused by a failure in the joint 

between the two lower segments of the 

right Solid Rocket Motor. The specific 

failure was the destruction of the seals 

that are intended to prevent hot gases 

from leaking through the joint during 

the propellant burn of the rocket motor. 

The evidence assembled by the Commission indicates that no other element of 

the Space Shuttle system contributed to 

this failure. 

During the period of the flight when the 

Solid Rocket Boosters are thrusting, there 

are no survivable abort options. There 

was nothing that either the crew or the 

ground controllers could have done to 

avert the catastrophe.37

The commission issued recommendations to 

fix the Solid Rocket Boosters and to change 

the engineering and management culture surrounding the human space flight enterprise. 

The commission also issued several ancillary 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

383

recommendations, including ones to improve 

launch-abort and crew-escape options. “The 

Shuttle program management considered firststage abort options and crew escape options 

several times during the history of the program, but because of limited utility, technical 

infeasibility, or program cost and schedule, no 

systems were implemented. The Commission 

recommends that NASA: Make all efforts to 

provide a crew-escape system for use during 

controlled gliding flight.”38

In a report attached to a July 14, 1986, letter 

from NASA Administrator James Fletcher 

to President Reagan, NASA provided the 

status of implementing the recommendations 

of the Rogers Commission of interest to this 

history work.

On April 7, 1986, NASA initiated a 

Shuttle Crew Egress and Escape review. 

The scope of this analysis includes egress 

and escape capabilities from launch 

through landing and will provide analyses, concepts, feasibility assessments, cost, 

and schedules for pad abort, bailout, ejection systems, water landings, and powered flight separation... Crew escape and 

launch abort studies will be complete on 

October 1, 1986, with an implementation decision in December 1986.39

The egress and escape review conducted an 

extensive, if quick, study of available options. 

Various proposals for ejection seats, separable 

capsules, and escape pods were evaluated 

and rejected based on performance, schedule, or budget. In the end, two options were 

evaluated in detail: a tractor rocket-extraction 

system and a telescopic escape pole. In both 

cases, the astronauts would use personal parachutes to bail out of the orbiter. Engineers 

considered both methods useful only below 

230 mph and 20,000 feet during controlled 

gliding flight. The tractor rocket system used 

small rockets attached to individual parachutes 

that could be fired from the crew-access hatch 

to propel crewmembers clear of the orbiter. 

The telescopic escape pole used a springloaded pole that extended 9.8 feet downward 

from the crew-access hatch to guide crewmembers away from the orbiter 

and under the left wing.40

The harness assembly 

worn over the S1032 also 

contained sleeves on each 

side of the back for the 

emergency oxygen cylinders 

and across the front for the 

floatation device. Note the 

“green apple” that activated 

the emergency oxygen.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

384

The parachute itself 

attached the harness 

assembly at four locations. 

Note the D-ring on the 

left shoulder strap (right in 

photo). The black object on 

each strap is a SEAWARS 

device that automatically 

released the parachute upon 

immersion in saltwater. 

NASA

William A. Chandler, crew system escape manager at JSC, noted that although both systems 

provided adequate escape clearance for the 

crew, the slide-pole system was safer and more 

cost effective over the life of the orbiters. This 

system was not meant as a means of escape 

in a Challenger-type scenario, as it assumed 

that the orbiter was in a recoverable mode 

and could be safely maneuvered to a stable, 

subsonic glide with minimum sink rate.41

The escape system was installed in the 

remaining orbiters during the standdown 

between 1986 and 1988. These modifications 

allowed crewmembers to equalize the 

pressure in the crew module with the outside 

atmosphere, pyrotechnically jettison the 

side hatch, and bail out from the middeck 

after manually deploying the escape pole. 

One by one, each crewmember would attach 

a lanyard hook assembly that surrounded 

the deployed escape pole to their parachute 

harness and egress through the side hatch 

opening. Attached to the escape pole, the 

crewmember would slide down the pole 

and off the end on a trajectory that took 

them away from the fuselage and below the 

left wing. Changes were also made to the 

orbiter flight control software to provide an 

automatic-mode that established a stable 

gliding flight for crew bailout.42

This escape system was tested on a USAF 

Lockheed C-141B Starlifter during the spring 

of 1988. The modifications to Discovery 

(OV-103) were completed on April 15, 1988, 

and the system was operational in time for 

the launch of STS-26R, the first flight after 

Challenger. The escape pole, as well as an 

inflatable escape slide for use during ground 

evacuations, was subsequently installed on 

Columbia (OV-102) and Atlantis (OV-104) 

before their return to flight and were 

production features on Endeavour (OV-105).43

As part of the new escape system, NASA 

physiologists determined the crewmembers 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

385

A mixture of S1032 suit 

colors in the simulator at 

the Johnson Space Center 

during 1988. The initial 

prototype and first 10 suits 

used dark-blue exterior 

covers and the last 38 suits 

used orange covers. NASA 

also bought two spare orange 

covers. Astronauts used the 

dark-blue suits only for 

training and they never flew.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

386

needed a pressure suit to provide personal 

protection during emergencies. Initially, 

NASA called the ensemble the Crew Protective 

System (CPS), then the Crew Altitude 

Protective System (CAPS), before settling on 

the Launch Entry Suit (LES) nomenclature. 

On February 11, 1987, the Lockheed 

Engineering and Management Services 

Company, the prime contractor for flight 

crew equipment (FCE) issued a $300,000 

subcontract to the David Clark Company for 

the development of a single prototype.44

A team of NASA, David Clark, and Lockheed 

researchers evaluated various pressure suits 

before deciding to adopt something similar 

to the High-Altitude Protective Outfit used 

at the NASA Dryden Flight Research Center. 

The ensemble offered a reasonable combination of comfort and protection and could be 

available in a short time. Contrary to most 

reports, the suit was not a variant of the 

CSU-4/P partial-pressure suit, although the 

bladder system used in the LES was generally 

similar. Most of the other major components 

had been developed, qualified, and flown 

previously as part of various aircrew protective systems. Thus, the development effort 

was largely one of integrating the components 

with each other and with the orbiter.45

The designers selected a nonconformal (dome) 

helmet since it virtually eliminated head-borne 

weight, was comfortable, and provided a wide 

field of view. The helmet provided a complete 

head and neck enclosure with no direct body 

contact above the shoulders. A large, moveable 

pressure visor provided good forward and 

peripheral vision. Side and rearward visibility 

was accomplished by manually rotating 

the helmet using a bearing on the neck 

ring. The helmet traced its origins to the 

S1010D nonconformal helmet developed 

in 1978 under USAF sponsorship. A single 

prototype of the S1010D accumulated more 

than 1,400 hours in the U-2R before being 

rejected in favor of a conformal helmet 

based on the S1030 design. David Clark 

Company addressed the original complaints 

of inadequate fore-aft stability by installing 

adjustable wire supports under the helmet 

disconnect ring.46

The neck ring had a latch that secured the 

helmet to the suit. Sliding the latch halves 

together moved six latch-dogs to secure 

the helmet on the neck ring. Sliding them 

apart retracted the dogs, allowing the helmet 

to be removed from the neck ring. Two 

independently operating polycarbonate and 

acrylic visors provided a clear pressure visor 

and a dark sunshield. The crewmember closed 

and locked the pressure visor by pulling the 

visor and the bailer bar down into the locked 

position. To open the pressure visor, a latch on 

the bailer bar lock had to be pushed down and 

two buttons on either side of the lock pressed. 

This allowed the bailer bar to unlock, after 

which the visor could be opened. The helmet 

had to be attached to the neck ring and the 

pressure visor closed and locked to pressurize 

the suit.47

Dual earphones and a flexible boom-mounted 

microphone were installed on a lightweight 

fabric “Snoopy Cap” communications carrier 

worn under the helmet. (A second microphone was added to the second production 

batch of suits.) Like the S1030A and LEH 

helmets before it, a pressure switch between 

the oxygen-delivery system and communication circuitry muted the microphone during 

inhalation. The comm carrier included head 

buffeting-protection padding and a large mesh 

area at the top to minimize heat buildup. The 

communications cable passed through the 

lower left side of the helmet and connected to a 

headset interface unit, which in turn connected 

to the orbiter communications system.48

The first LES prototype used a relatively simple torso counter-pressure garment designed 

to interface with the helmet via the disconnect bearing assembly and with a lower-body 

counter-pressure garment similar to a cutaway 

G-suit, except it contained two separate bladders: one for altitude protection and one 

for acceleration protection. The ensemble 

included counter-pressure sleeves and standard 

partial-pressure gloves to provide physiological protection comparable to the CSU-4/P 

partial-pressure suit. David Clark Company 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

387

The following illustrations 

show the various layers of 

the S1032 Launch Entry 

Suit (LES). The layer closest 

to the wearer was a set of 

long underwear and socks. 

For men, this included 

an athletic supporter and 

urine-collection device.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

388

The counter-pressure garment contained the bladders 

that provided altitude protection if needed. This layer 

also included unpressurized 

Gore-Tex fabric sections that 

protected the wearer against 

cold-water immersion and 

allowed ventilation air to 

circulate within the suit. 

The dark-blue areas illustrate the cutaway G-suit.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

389

The restraint layer was a 

relatively unyielding garment that allowed the 

counter-pressure garment 

to press inward toward 

the wearer when inflated. 

As with all pressure suits, 

the trick was to make the 

restraint layer unyielding 

to internal pressure but still 

provide sufficient mobility 

for the wearer to accomplish 

their tasks. Note the use of 

Link-Net around the shoulders to increase flexibility. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

390

The outer cover is what 

most people think of when 

they consider pressure suits, 

although the suit is perfectly 

capable of operating without 

it. Early LES suits used 

dark-blue Nomex covers 

while all operational suits 

used orange Nomex for 

enhanced visibility during 

search and rescue operations. 

Note the emergency oxygen 

cylinders suspended from 

the shoulders.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

391

Next came the parachute 

harness, floatation devices, 

and various other supplies. 

Note that the communications carrier assembly is 

separate from the helmet.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

392

The final items included the 

helmet and gloves. Note the 

location of the “green apple” 

that was used to initiate the 

flow of emergency oxygen, 

the knife pocket on the 

inside of the left thigh, and 

the ripcord D-ring handle. 

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

393

delivered the first prototype to the Johnson 

Space Center on June 2, 1987.49

The original specification for the CAPS did 

not include cold-water immersion protection. 

However, David Clark Company engineers 

soon learned that NASA intended to provide water-immersion protection through a 

separate over-garment. This would greatly 

complicate the donning and doffing process 

on orbit, so David Clark Company unilaterally decided to incorporate immersion protection into the basic ensemble. As originally 

conceived, the S1032 was a simple modular 

design that covered only the portions of 

the body required for emergency hypobaric 

protection, thereby minimizing heat loading. The addition of immersion protection 

required completely covering the body with 

water-impermeable materials, resulting in 

considerable metabolic heat loading. To minimize heating and its associated perspiration, 

David Clark Company integrated breathable 

Gore-Tex fabric with the pressure bladders 

to form a watertight coverall with an integral 

ventilation system. The vent system consisted 

of an inlet on the left front of the coverall 

torso, airtight vent ducts routed through the 

torso pressure bladder to several outlets in the 

inner bladder wall, and check valves to allow 

vent air to channel through the pressure bladder for exhaust via the pressure controller. 

Although complicating the garment itself, the 

integration of immersion protection within 

the S1032 nonetheless resulted in a simplified 

system from a crewmember standpoint.

For the legs, the G-suit and altitude-protection 

bladders used the same restraint layer. This 

A modified S1030 fullpressure suit controller was 

located on the right side of 

the chest (left in the photo) 

and the ventilator valve 

was located on the left side. 

Because the S1032 was 

only a partial-pressure suit, 

the control aneroid was 

rescheduled to maintain 

only 2.8 psi instead of the 

3.5 psi used by the S1030 

(and S1030A).

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

394

Despite being a partial-pressure suit, the S1032 looked very 

much the part of a full-pressure suit. In front, the parachute 

harness is clearly visible, as is the emergency flotation-device 

housing around the chest. At the back, the parachute is 

flanked by an emergency oxygen cylinder on each side.

NASA

design theoretically provided greater acceleration protection than the standard military 

cutaway G-suit since it provided contiguous 

coverage through the knee, hip, and groin 

areas and had slightly greater bladder area coverage, similar to the recent full-coverage G-suit 

employed in fighter aircraft. The G-suit was 

only used during entry. 

David Clark Company selected the standard 

S1030 full-pressure suit dual system controller 

for the S1032. However, given the partial-pressure suit application, the control aneroid was 

rescheduled to maintain a minimum absolute 

pressure of 2.8 psi, instead of the 3.5 psi used 

by the S1030. The harness assembly contained 

a torso harness, an enhanced life preserver unit, 

a freshwater-pouch assembly, an emergency 

rescue package that contained flares and a 

knife, and a two-bottle emergency oxygen supply that provided 10 minutes of life support.

The first production S1032 suit was delivered 

to NASA on February 8, 1988. Researchers at 

the USAF School of Aerospace Medicine conducted altitude chamber tests and concluded 

that the S1032 provided acceptable protection 

at 100,000 feet. Cold-water tests at the Naval 

Air Development Center showed the suit 

provided more than 3 hours of protection for 

subjects immersed in 40 oF water.50

Lockheed issued three separate purchase 

orders to the David Clark Company for 

S1032 suits. The first, on September 4, 1987, 

was for six suits to support system certification 

training and STS-26R crew training. David 

Clark Company fabricated these suits using 

dark-blue Nomex exterior covers, same as 

the prototype. Each suit cost $84,180. David 

Clark commenced deliveries on February 8 

and completed them on February 25, 1988.51

The second purchase order was issued on 

November 11, 1987, for 10 suits at a cost of 

$84,180 each. The order was modified on 

April 14, 1988 to add a second microphone 

to each suit and to change the configuration 

of the leg pockets to more closely match the 

S1030A. Six of these suits were fabricated 

using orange Nomex covers for enhance 

visibility during search and rescue operations. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

395

Dual earphones and a flexible boom-mounted microphone 

were installed on a lightweight fabric “Snoopy Cap” 

communications carrier worn under the helmet. The 

communications cable passed through the lower left side of the 

helmet and connected to a headset interface unit, which in 

turn connected to the orbiter communications system. Here, 

the white cable is tucked into a pocket on the exterior cover.

NASA

The other four used dark-blue exterior 

covers. David Clark Company delivered the 

first suit on March 4, 1988, and the last on 

September 9, 1988.52

The last production order was issued on 

August 18, 1988, for 32 suits at a cost of 

$88,769 each. All of these included dual 

microphones and orange Nomex outer covers. 

These suits were provided in six additional 

sizes (small regular, small long, large short, 

and extra-large short, regular and long). 

Lockheed also ordered two extra orange 

exterior covers for $3,372 each. The first suit 

was delivered on October 28, 1988, and the 

last on April 24, 1990.53

Although David Clark Company developed 

patterns for the standard 12 sizes, only 

10 different sizes were ultimately delivered.54

The flotation system initially used with the 

LES was an Air Force model used by T-38 

aircrews. However, during cold-water immersion tests, subjects assumed a horizontal position in the water that allowed the aspiration 

of water through the anti-suffocation valve 

located on the back of the LES helmet; this 

both exacerbated thermal stress and increased 

the risk of drowning. Subsequently, NASA 

adopted a modified Navy flotation system that 

worked reasonably well but used a makeshift 

interface with the LES. Water inflow through 

the anti-suffocation valve continued to be a 

problem, despite the approximate 45-degree 

angle relative to the water surface assumed by 

floating subjects. Eventually, DDC designers 

suggested using the flotation system used by 

SR-71 crews that placed subjects in a relatively 

upright position (i.e., approximately perpendicular to the water surface).55

During 1990, David Clark Company added 

a biomedical instrumentation port (BIP) to 

the LES suits. Informally called a “hole-inthe-suit,” this port on the right thigh could 

accommodate biomedical instrumentation 

as needed. A blank plug covered the port 

when not in use. In 1992, David Clark Company modified the LES neck seal by adding 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

396

In 1988, before the return-to-flight of STS-26R, NASA 

astronaut and flight surgeon Jim Bagian conducted a mobility study that compared the original shirtsleeve/LEH environment with the then-new S1032. Here Bagian demonstrates 

that the LES allowed reaching behind him while wearing the 

emergency oxygen cylinders and parachute pack.

NASA

pull-tabs and Velcro to improve ventilation to 

the head and neck during prelaunch and postlanding when the crew was sitting in the seat 

for extended periods.56

Before the return-to-flight of STS-26R in 

1988, NASA astronaut and flight surgeon 

James P. Bagian conducted a study of the 

mobility of the original LEH shirtsleeve 

ensemble and the then-new LES garment. 

Primarily, Bagian and researcher Lauren W. 

Schafer from Lockheed Engineering & Sciences Company,57 were interested in how the 

different ensembles affected the ability of the 

crew to reach various controls in the orbiter. 

Seven veteran astronauts and four airmen volunteers were tested on the human centrifuge 

at the USAF School of Aerospace Medicine 

at Brooks AFB to find the answer. The subjects were strapped into a seat that mimicked the launch orientation of the orbiter 

and instructed to conduct a series of “reach 

sweeps” that were measured by researchers 

using high-speed video. Each sweep began 

with the hand on the knee, reached 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

397

Bagian in the vertical middeck simulator at JSC. Note the 

“green apple” that initiates the flow of emergency oxygen. The 

outermost orange tubes across the chest was the floatation 

device (life vest). Note how cramped the seating arrangement 

is, with the middeck lockers only a couple of feet away. 

NASA

directly forward, sweeping back toward the 

aft wall of the gondola, to a position over 

the head, and finally back to the knee. Tests 

were conducted at 1-G (gondola sitting still) 

and at +3-Gz, about the maximum reached 

during a Space Shuttle ascent.58

All of the subjects practiced the sweeps multiple times to familiarize themselves with the 

action and encumbrances of both types of 

suits. Bagian commented, “The changes in 

forward reach were qualitatively what had 

been expected based on anecdotal reports.”59

On the average, the subjects experienced a 

1.45-inch reduction in forward reach at +3-Gz 

versus 1-G for both suits. This was not as 

great a reduction as the researchers expected. 

The study also found that the forward reach 

in the LES was 2.40 inches less than in the 

LEH at each acceleration level. Bagian concluded that, “the reduction in forward reach 

capability of 13 percent was inherently due 

to the change in required crew equipment.”60

Interestingly, right overhead reach was found 

to be 2.00 inches (8 percent) greater than the 

left for both suits at each acceleration level. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

398

Robert R. “Bob” Banks 

from the David Clark 

Company (DCC) models 

the prototype S1035 fullpressure suit on April 20, 

1990. Based largely on 

the success of the Air Force 

S1034 development effort, 

this prototype was used for 

the initial comparisons with 

the existing S1032 suits. 

Note the DCC patch on the 

right chest. 

Courtesy of the David Clark 

Company, Inc.

Since the garments were symmetrical, Bagian 

attributed the difference to the parachute harness worn over each ensemble. Although not 

part of the study, each subject reported that 

the field of view provided by the LES helmet 

was substantially greater than the LEH.

Bagian, who has long been one of the most 

vocal proponents of the need to provide better protective equipment for Space Shuttle 

crewmembers, concluded, “Although the LES 

permitted less forward and overhead reach 

capability than its predecessor, the LEH, the 

observed reductions are offset by the expanded 

crew escape and survival potential provided by 

this new suit.”61

In 1990, David Clark Company completed 

the development and qualification of the 

Air Force S1034 Pilots Protective Assembly 

full-pressure suit. At the time, NASA was 

looking to procure additional LES ensembles 

and this presented an opportunity to reconsider the benefits of partial versus full-pressure 

suits. David Clark Company fabricated a 

prototype S1035 full-pressure ensemble for 

NASA in 1990, based largely on the S1034 

design. The new suit was considerably lighter, 

less bulky, cooler, and more comfortable than 

the S1032, used the same helmet and pressure 

controls as the S1032, and provided better 

physiological protection and more mobility. The prototype evolved into the S1035 

Advanced Crew Escape Suit (ACES).62
399

David Clark Company configured the exterior cover of the 

S1035 identically to the S1032, and the two are largely 

indistinguishable without careful examination. This might 

explain why NASA public affairs continued to refer to 

LES suits until the end of the program, ignoring the ACES 

designation entirely. The easiest way to tell the suits apart 

at a glance is to see how the gloves are connected; if they 

use a wrist ring, it is an S1035. This is the STS-129 crew 

during the terminal countdown demonstration test (TCDT) 

emergency egress training.

NASA

The LES supported 42 Space Shuttle 

missions, beginning with STS-26R in 

September 1988 and ending with STS-98 

on February 7, 2001. The dark-blue LES 

ensembles never flew in space, being relegated 

to training purposes. NASA continued to use 

the suits for some training until the end of 

the program in 2011, long after the LES was 

retired from flight duties.

S1035—ADVANCED CREW ESCAPE 

SUIT (ACES)

The prototype S1035 fabricated by David 

Clark Company in 1990 heavily leveraged the 

technologies developed for the USAF S1034 

Pilots Protective Assembly. Since the existing 

S1032 partial-pressure suits were nearing the 

end of the service lives, the S1035 provided 

NASA a low-risk path to upgrade to a fullpressure suit. Lockheed engineers compared 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

400

This illustration shows 

the location of the dual 

suit controller, ventilation 

connection, and the 

bioinstrumentation 

pass-through. All of this 

hardware was identical to 

(and mostly salvaged from) 

the earlier S1032 suits.

NASA

the prototype S1035 to the S1032 LES in 

regards to reach and treadmill performance 

and found no significant differences. Favorable crew evaluations of the prototype S1035 

led to full-scale development in 1992.63

David Clark Company began production 

of the S1035 Advanced Crew Escape Suit 

(ACES) in February 1993 and delivered the 

first article to NASA in May 1994. In a switch 

from the usual scenario, the S1035 entered 

production and operational service before the 

S1034 from which it was derived.64

As a cost savings, David Clark Company 

removed significant hardware from the S1032 

suits and reused it on the S1035 suits. This 

included the dual-system suit controllers, neck 

rings, neck seal, relief valves, helmets, helmet 

holddown hardware, and the oxygen manifold 

behind the neck ring. The suit controllers, 

oxygen-breathing regulators, exhalation valves, 

and relief valves were rescheduled to operate at 

3.5 psi for ACES instead of the 2.8 psi used in 

the LES.65 To minimize training requirements, 

the exterior coverall was configured identical 

to the last S1032s and used the same biomedical instrumentation pass-through. Because of 

this, the pocket configuration on the S1035 

differs from the S1034.66

Several of the material/configuration changes 

that David Clark Company adopted to satisfy 
401

other design objectives resulted in a 

marked improvement in the comfort of the 

ACES compared to the LES. Particularly, 

this included the use of a breathable gascontainer material and the elimination of 

a separate restraint layer in the legs. The 

S1034 glove also provided better comfort and 

mobility. This glove used a bladder assembly 

fabricated from breathable materials in the 

wrist, palm, and backhand areas to reduce 

thermal load. It also used an outer restraint 

with a combination of flat and tucked 

patterning to reduce the torque needed to 

flexion-extension of the hand joints in both 

pressurized and unpressurized modes. In 

addition, new wrist disconnects incorporated 

low-torque bearings to minimize the forces 

associated with repeated rotations of the 

wrist. Standard, commercial-off-the-shelf 

Rocky 911 boots were worn over ACES 

pressure-bladder booties.67

The design and construction of the S1034 

and S1035 were essentially identical, although 

there were differences in the integration 

of accessories due to differing modes of 

crew escape and mission objectives. Visible 

differences between the two suits included 

the suit controller and vent connector being 

closer together on the S10135 because NASA 

used a Mustang parachute harness instead of a 

standard USAF unit. Less noticeable was that 

the S1035 did not use an inner comfort liner, 

a vent system, or a urine-collection system. 

A comparison of the S1032 

partial-pressure suit glove 

and the S1035 full-pressure 

suit glove. Like most partialpressure gloves, the S1032 

glove was not directly 

attached to the suit except 

through the ventilation 

tube, while the full-pressure 

glove used a lock-ring that 

tightly secured it to the suit.

Courtesy of the David Clark 

Company, Inc.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

402

Table 10—S1034 Requirements Classification

Component USAF S1034 PPA NASA S1035 ACES

Helmet Conformal helmet with face seal, 

integrated anti-suffocation valve, 

breathing regulator, exhalation 

valves, food and liquid intake 

pass-through, integrated and selfcontained communication

Dome (nonconformal) helmet, larger 

neck ring, integrated anti-suffocation 

valve, and communication connection. 

(Communication provided as a separate 

communication carrier assembly.)

Coverall Outside Nomex cover, Link-Net 

restraint, Gore-Tex bladder/ 

exposure layer and inner 

comfort liner.

Identical to S1034 except no inner 

comfort liner and coverall provisions for 

oxygen pass-through and G-suit oxygen 

manifold. NASA system used an integrated neck seal because of dome helmet use.

Hardware Neckring and glove disconnects 

with low-torque bearings, vent inlet fitting and duct system, helmet 

holddown system.

Identical hardware components with the 

addition of a G-suit pressure controller/

oxygen manifold, biomedical pass-through 

and dome helmet-support springs.

Pressure 

Controls

Dual suit-controller assembly, 

oxygen-breathing regulator located 

in helmet, suit relief valve, exhalation valves located in helmet.

Identical except oxygen-breathing regulator (single system) was located in the suit 

and exhalation valves were located in the 

suit neck seal.

Gloves Full-pressure suit glove with wrist 

disconnects.

Identical

Source: Phil Landis and Phil Hooper, “Assessment of the S1035 Advanced Crew Escape Suit 

for Use in the Space Launch Initiative program,” Lockheed Martin Space Operations report 

LMSEAT-34099, January 16, 2003.

In addition, the S1035 had provisions to use 

an Anti-G Suit (AGS) under the pressure suit 

during entry.68

The AGS was fabricated from Nomex 

and nylon with counter-pressure bladders 

configured generally similar to the standard 

USAF “5 bladder” cutaway G-suit. Lacing on 

the waist and legs allowed some customization 

for fit. The AGS was pressurized with suit 

oxygen and the connection to the orbiter 

was through a self-sealing connector that 

permitted the crewmember to wear the S1035 

by itself (standard launch configuration), 

Various pieces of crew-worn equipment include an S1035 

ACES, along with its harness assembly and AGS (left), a 

diaper, the communications carrier and helmet, boots, and 

cold-weather over-gloves.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

Above: From the back, the S1035 shows its long vertical rear- 403

entry zipper and the harness assembly with side pockets that 

held emergency oxygen cylinders. Note the booties sticking out 

of the legs of the S1035; these were permanently connected to 

the gas container inside the suit.

Right: The crew of STS-95 show off their ACES full-pressure 

suits. This was a highly publicized mission due to former 

Mercury astronaut and U.S. Senator John H. Glenn, Jr.’s 

return to space for his second space flight, at age 77. 

Re-creating a famous Mercury Seven pose are (left to right, 

front): Steven K. Robinson, Curtis L. Brown, John H. Glenn, 

and Scott E. Parazynski; (left to right, back): Pedro Duque 

(ESA), Chiaki Mukai (NASDA), and Steven W. Lindsey. 

NASA

the S1035 with the AGS (standard entry 

configuration), or the AGS by itself without 

the pressure suit.69

In the SR-71 and U-2, the pilot wore all of 

his equipment when he entered the aircraft 

and sat on an ejection seat. Astronauts, on 

the other hand, wore only their pressure suits 

when they entered the orbiter and sat on 

lightweight crew seats. The USAF parachute 

system was contained within the seat along 

with a survival kit, whereas the Space 

Shuttle system used a stand-alone parachute 

positioned in the orbiter seat backs and 
404
405

Not really intended as a demonstration of the flexibility 

of the S1035 suit, the STS-132 Space Flight Awareness 

photos at Minute Maid Park in Houston on February 11, 

2010, nevertheless provided some insight. The crew horsed 

around in training versions of the suit, pretending to play 

baseball and cricket, and generally having fun.

NASA
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

406

Table 11—Space Shuttle Crewmember Protection by Mission

Mission Date CDR PLT MS1 MS2 MS3 MS4 MS5

STS-1 

through 

STS-4

— S1030A S1030A — — — — —

STS-5 

through 

STS-33

— LEH LEH LEH LEH (LEH) (LEH) (LEH)

STS-26R 

through

STS-65

— LES LES LES LES (LES) (LES) (LES)

STS-64 Sep 9, 1994 LES LES ACES LES ACES LES —

STS-68 Sep 30, 1994 ACES ACES LES LES LES LES —

STS-66 Nov 3, 1994 LES LES LES LES LES LES —

STS-63 Feb 3, 1995 ACES ACES ACES ACES LES LES —

STS-67 Mar 2, 1995 LES LES LES LES LES LES LES

STS-71 Jun 27, 1995 ACES ACES ACES ACES LES LES LES

STS-70 Jul 13, 1995 ACES LES LES ACES LES — —

STS-69 Sep 7, 1995 LES ACES LES ACES LES — —

STS-73 Oct 20, 1995 LES ACES LES ACES ACES LES LES

STS-74 Nov 12, 1995 ACES ACES LES LES ACES — —

STS-72 Jan 11, 1996 LES LES ACES LES LES ACES —

STS-75 Feb 22, 1996 LES ACES LES ACES LES ACES LES

STS-76 Mar 22, 1996 ACES ACES LES LES LES LES LES

STS-77 May 19, 1996 LES LES LES LES LES LES LES

STS-78 Jun 20, 1996 LES ACES LES ACES LES LES LES

STS-79 Sep 16, 1996 ACES ACES LES LES LES LES LES

STS-80 Nov 19, 1996 LES LES LES LES LES — —

STS-81 Jan 12, 1997 LES LES LES LES LES LES LES
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

407

Table 12—Space Shuttle Crewmember Protection by Mission (continued)

Mission Date CDR PLT MS1 MS2 MS3 MS4 MS5

STS-82 Feb 11, 1997 LES ACES ACES ACES ACES LES ACES

STS-83 Apr 4, 1997 ACES ACES ACES ACES ACES LES LES

STS-84 May 15, 1997 ACES ACES ACES ACES ACES ACES ACES

STS-94 Jul 1, 1997 ACES ACES ACES ACES ACES LES LES

STS-85 Aug 7, 1997 ACES ACES ACES ACES ACES LES —

STS-86 Sep 25, 1997 ACES ACES ACES ACES ACES ACES ACES

STS-87 Nov 19, 1997 ACES ACES ACES ACES ACES LES —

STS-89 Jan 22, 1998 ACES ACES ACES ACES LES ACES ACES

STS-90 Apr 17, 1998 ACES ACES ACES ACES ACES LES LES

STS-91 Jun 2, 1998 ACES ACES ACES ACES ACES ACES ACES

STS-95 Oct 25, 1998 ACES ACES ACES ACES ACES ACES ACES

STS-88 Dec 4, 1998 ACES ACES ACES LES ACES ACES —

STS-96 May 27, 1999 ACES ACES ACES ACES ACES ACES ACES

STS-93 Jul 23, 1999 ACES ACES ACES ACES ACES — —

STS-103 Dec 19, 1999 ACES ACES ACES ACES ACES ACES ACES

STS-99 Feb 11, 2000 ACES ACES ACES ACES ACES ACES —

STS-101 May 19, 2000 ACES ACES ACES ACES ACES ACES ACES

STS-106 Sep 8, 2000 ACES ACES ACES ACES ACES ACES ACES

STS-92 Oct 11, 2000 ACES ACES ACES ACES ACES ACES ACES

STS-97 Nov 30, 2000 ACES ACES ACES ACES ACES — —

STS-98 Feb 7, 2001 ACES ACES ACES ACES ACES — —

STS-102 

through 

STS-135

— ACES ACES ACES ACES (ACES) (ACES) (ACES)

Source: Bruce W. Sauser (NASA/JSC), Carlton F. “TC” Thomas (USA/JSC), and Ronald C. Woods (NASA/KSC).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

408

Seven S1035 suits await their crew prior to the last flight of 

Columbia, STS-107.

Courtesy of the David Clark Company, Inc.

connected to the harness assembly after orbiter 

ingress. Both parachute systems were based 

upon a pilot, drogue, and reefed main-canopy 

system. When these systems were initiated, 

a pilot chute deployed a drogue chute that 

provided speed and orientation stabilization 

until reaching 14,000-feet altitude, at which 

time the main-canopy deployed (in the case of 

the U-2R and SR-71, this occurred at pilotseat separation). The SR-71 main canopy 

parachute was 35-feet in diameter, compared 

to 28 feet in the U-2R and 26 feet in the 

Space Shuttle.70

Breathing oxygen came from the orbiter supply, the emergency oxygen system (EOS) at 

each seat, or from carry-around bottles that 

allowed crewmembers to move about the 

crew module. The ACES breathing regulator 

delivered 100 percent oxygen to the helmet 

at slightly above suit pressure. This resulted 

in oxygen-enriched air being exhaled into the 

crew module. Over time, this increased the 

oxygen concentration in the crew module, 

creating the potential for fire. Therefore, the 

amount of time that crewmembers had their 

visors down and were breathing 100 percent 

oxygen was operationally limited except, of 

course, during emergencies.71

The EOS was located within the parachute 

pack and consisted of two 3,000-psi oxygen 

bottles (381 liters total) with regulators that 

reduced the pressure to 70 psi. A common 

manifold delivered 70-psi oxygen from both 

bottles to a hose that connected to the ACES 

oxygen manifold. Pulling the “green apple” 

knob on the right side of the harness activated 

the system.

Crewmembers wore various garments under 

the ACES and G-suit for comfort. These 

included a liquid-cooling garment, thermal 

underwear, wool socks, and a diaper (unlike 

the S1034, the S1035 did not include a 

urine-collection system). The liquid cooling garment consisted of thermal underwear, 

shirt, and trousers with tubes sewn into the 

fabric. A thermoelectric liquid-cooling unit or 
409

Lockheed test pilot William A. “Bill” Weaver in front of an 

SR-71 wearing a David Clark Company S901 suit adapted 

for use with the SR-71A. On 25 January 1966, Weaver 

survived after his SR-71A (61-7952) broke up at Mach 3 

and 75,000 feet. (See story on the following page.)

Courtesy of Lockheed Martin Aeronautics

individual-cooling unit pumped chilled water 

through a network of tubing in the liquidcooling garment to cool the crewmember. 

The water supply and return lines were fed 

through a plug located on the right thigh of 

the ACES.72

Like the LEH and LES before it, the ACES 

was supported by the orbiter oxygen system 

with four connections on the flight deck and 

four on the middeck. The middeck connections each had a tee that supported two connections, for eight available connections in all 

on the middeck. Each of these 12 connections 

could support an ACES or a Quick-Don 

Mask (QDM) assembly that was used for 

on-orbit contingency operations.73

As it had for the S1034 PPA, David Clark 

Company examined all available anthropometric data to determine if the existing 12-size 

tariff was still valid for the S1035. The conclusion was the same as it had been for the 

S1034, namely that the 12 sizes provided an 

adequate fit from the 5th to the 95th percentile of expected wearers, including females. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

410

However, the increased range of sizes for personnel in the Space Shuttle and International 

Space Station (ISS) programs led to the addition of an extra-small category and a small 

regular modified subcategory. David Clark 

Company ultimately fabricated 62 S1035 suits 

for the Space Shuttle Program.74

There were proposals to give the S1035 suits 

to the NASA WB-57F operation at nearby 

Ellington Field after the Space Shuttle retired 

in 2011. The engineers at David Clark 

Company pointed out that it would be costly 

to modify the S1035s to work with the 

WB-57Fs since the suits were considerably 

different than the S1034 PPAs used by 

the WB-57F crews. Although much of the 

hardware could be salvaged from the S1035s 

and used to build new S1034s, actually 

converting the S1035s would have been 

prohibitively expensive.75

COMPARING COLUMBIA TO AN 

SR-71 BREAKUP

As part of the investigation into the 

Columbia accident during STS-107 in 2003, 

the Spacecraft Crew Survival Integrated 

Investigation Team compared the breakup 

of Columbia to a similar breakup of an 

SR-71A (61-7952) on January 25, 1966. 

The Blackbird suffered a structural failure 

during a high-speed turn and broke apart 

at approximately Mach 3 and 75,000 feet. 

This translates to approximately 400 knots 

equivalent air speed (KEAS). Lockheed pilot 

William A. “Bill” Weaver was thrown clear 

of the wreckage and blacked out during the 

accident but recovered and landed safely. 

James T. “Jim” Zwayer in the back seat 

apparently broke his neck as his helmet hit the 

Mach 3 slipstream and did not survive. While 

three other crewmembers lost their lives in the 

A-12 and M-21 programs, Zwayer was the 

only fatality in an SR-71.76

Although seemingly dissimilar, the two 

accidents shared some common traits. For 

instance, in both accidents, crewmembers 

were involuntarily separated from the 

vehicle when the seat restraints failed. The 

S901J pressure suits worn by the SR-71 

crew were a distant relative of the S1035 

pressure suits worn by the Columbia crew 

but provided essentially similar protection. 

Most importantly, from an investigation 

perspective, the dynamic pressure when 

the Columbia crew module broke up was 

approximately 405 pounds per square 

foot (psf), and the dynamic pressure at 

SR-71 breakup was roughly 398 psf, a 

difference of less than 2 percent.

However, there are also notable differences 

between the two accidents. Bill Weaver’s 

S901 suit pressurized automatically, as 

designed, when the cockpit depressurized due 

to the aircraft breakup. The pilot attributed 

his survival to the pressurized suit, which 

protected him from the low-pressure and 

low-oxygen environment, as well as the 

aerodynamic forces experienced when he 

separated from the aircraft (and ejection seat). 

The Columbia suits did not pressurize because 

the astronauts had not lowered their visors 

to activate the suit oxygen system and three 

crewmembers had not donned gloves, required 

actions for the suit to pressurize. In addition, 

although the Columbia crewmembers were 

exposed to a similar dynamic-pressure 

environment as the SR-71 crewmembers, the 

thermal environment was much more severe 

during the STS-107 breakup and is believed 

to have been nonsurvivable.

In the Space Shuttle orbiter, the crew module 

is a separate, pressurized compartment housed 

within the forward fuselage. There are two 

levels in the crew module: the flight deck on 

top and the middeck below (there is also an 

uninhabited equipment compartment below 

the middeck). Aerodynamic analysis indicates 

that the Columbia forward fuselage failed at 

approximately 400 KEAS, exposing the crew 

module that then failed due to the combined 

effects of the high accelerations, aerodynamic 

forces, and thermal loads. The crew module 

depressurized 6 seconds after the forward 

fuselage broke apart, although the flight 

deck retained structural integrity longer than 

the middeck. The reduced drag of the crew 

module, once it separated from the forward 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Chapter 8: Space Shuttle Pressure Suits

411

fuselage, allowed it to accelerate to 560 KEAS 

during its fall before it disintegrated.77

David Clark Company designed the ACES 

to maintain structural integrity and pressure 

response when exposed to a 560-KEAS 

windblast. Because NASA certified the S1035 

based on its similarity to the S1034, it was not 

subjected to windblast tests for certification.78

However, as part of its certification process, 

in 1990, the USAF conducted two tests of 

the S1034 in a 600-KEAS windblast. For the 

USAF test, the suit contained a mannequin 

and was properly restrained in an ejection seat 

with the visor down and locked. During the 

first test (suit unpressurized), the sunshield 

separated from the helmet and a life preserver 

inflation tube separated from the life preserver 

unit. During the second test (suit at 2.99 psi), 

both calf pockets were forced open. No other 

relevant anomalies were observed in either 

test, and the Air Force certified the suit based 

on the results.79

In the USAF windblast test configuration, the 

helmet visors were lowered, whereas debris 

evidence indicates the Columbia helmet visors 

were up. With the helmet visor up, the helmet 

cavity presents a high-drag configuration that 

could contribute to a mechanical failure of the 

suit/helmet interface.80

The investigation team decided it did not have 

enough data about either accident or about 

the suit-certification process to come to any 

particular conclusions. There is little doubt, 

however, that not wearing a pressure suit 

properly has an adverse effect on the amount 

of protection it can provide. Nevertheless, 

even if the Columbia astronauts had been 

wearing the suit correctly, and the suits had 

protected the astronauts sufficiently to save 

them from the initial breakup, it is unclear 

how they would have survived the rest of the 

accident. Ultimately, the investigators issued 

several recommendations to improve future 

pressure suits.
412

ENDNOTES
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

413

Endnotes: Preface | Chapter 1

Endnotes

PREFACE 

1

 J.P. Henry, D.R. Drury, P.O. Greeley, and V.R. Bennett, “A Study 

of the Physiological Requirements of an Emergency Pressure 

Suit Permitting Survival at 60,000 feet,” part of Project MX-829, 

Aeromedical Laboratories, USC, May 5, 1946, as attached to 

USAAF/AMC Engineering Division Memorandum Report 

TSEAA-660-100, May 5, 1946.

CHAPTER 1 

1

 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV,” p.viii.

2

 Derived from the definition located at: http://dictionary.reference.

com/browse/vacuum.

3

 “Arabic and Islamic Natural Philosophy and Natural Science,” 

Stanford Encyclopedia of Philosophy, located at http://plato.

stanford.edu/entries/arabic-islamic-natural/

4

 Whatever Aristotle said, he did so in ancient Greek, but the 

usual translation is that “Nature abhors a vacuum.”

5

 John D. Barrow, The Book of Nothing: Vacuums, Voids, and the 

Latest Ideas About the Origins of the Universe (New York: Pantheon 

Books, 2000).

6

 There is considerable debate on whether Némore was truly the 

author, but it does not matter for the point of this discussion.

7

 Tony Rothman, Everything’s Relative: And Other Fables from 

Science and Technology (New York: John Wiley & Sons, 2003).

8

 W. E. Knowles Middleton, The History of the Barometer 

(Baltimore: Johns Hopkins Press, 1964).

9

 Aether originally was the personification of space and heaven in 

Greek mythology. Later, it would lend its name to Ethernet.

10 Isaac Asimov, Asimov’s Biographical Encyclopedia of Science and 

Technology (New York: Doubleday, 1964), entry 82.

11 Evangelista Torricelli, “De motu gravium naturaliter descendentium, et proiectorum libri duo,” in Opera Geometrica (Florence: 

Typis Amatoris Masse & Laurentii de Landis, 1644); biography 

of Evangelista Torricelli, located at http://www-history.mcs. 

st-andrews.ac.uk/Biographies/Torricelli.html

12 Which translates to New Experiments with the Vacuum.

13 I.H.B Spiers and A.G.H. Spiers, The Physical Treatises of Pascal

(New York: Columbia University Press, 1937).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

414

Endnotes: Chapter 1

14 Called the Magdeburg hemispheres because, at the time, Guericke 

was the Mayor of Magdeburg, the capital city of the Bundesland 

of Saxony-Anhalt, Germany. The original hemispheres are preserved in the Deutsches Museum in Munich.

15 Edwin H. Hall and Joseph Y. Bergen, A Textbook of Physics, 3rd Ed. 

(New York: Henry Holt & Co., 1903).

16 Robert Boyle, New experiments physico-mechanical, touching 

the spring of the air, and its effects, (made, for the most part, in a 

new pneumatical engine) (Oxford, Printed by H. Hall for 

Theodore Robinson, 1660).

17 Andrew Guthrie, Vacuum Technology (New York: John Wiley 

& Sons, 1963).

18 Aeromedical Training for Flight Personnel, Army FM 3-04.301 

(formerly FM 1-301) (Washington DC: U.S. Army, 2000).

19 Ibid.

20 Ibid.

21 Richard D. Vann (ed.), “The Physiological Basis of Decompression,” Thirty-Eights Undersea and Hyperbaric Medical Society 

Workshop, June 1989.

22 Phil Landis and Phil Hooper, “Assessment of the S1035 Advanced 

Crew Escape Suit for Use in the Space Launch Initiative Program,” 

Lockheed Martin Space Operations Report LMSEAT-34099, 

January 16, 2003.

23 Donn A. Byrnes and Kenneth D. Hurley, Blackbird Rising: 

Birth of an Aviation Legend (Los Lunas, NM: Sage Mesa 

Publications, 1999).

24 Ibid.

25 R.W. Bancroft, J.E. Dunn (eds), “Experimental Animal Decompression to a Near Vacuum Environment,” Report SAMTR-65-48 (Brooks AFB, TX: USAF School of Aerospace 

Medicine, June 1965).

26 U.S. Naval Flight Surgeon’s Manual, Naval Aerospace Medical 

Institute, Third Edition, 1991; data provided by Dr. Jan Stepanek 

at the Mayo Clinic.

27 J. Emsting, “Operational and Physiological Requirements for 

Aircraft Oxygen Systems,” AGARD Report No. 697, November 

1983; J. Emsting, “Minimal Protection for Aircrew Exposed to 

Altitudes above 50,000 feet,” Joint Airworthiness Committee 

Paper No. 1014, January 1983. 

28 For instance, the Federal Air Regulation governing pilots in the 

United States encourages the use of supplemental oxygen between 

10,000 and 12,500 feet and requires it above 12,500 feet with 

various exceptions for short-term exposure. The military and most 

other countries have similar regulations.

29 William J. Sears, “High-Altitude Pressure Protective Equipment: 

A Historical Perspective,” in “Raising the Operational Ceiling: A 

Workshop on the Life Support and Physiological Issues of Flight 

at 60,000 feet and Above,” ALlCF-SR-1995-0021, Andrew A. 

Pilmanis, and William J. Sears (eds), December 1995.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

415

Endnotes: Chapter 1 | Chapter 2

30 “High-Altitude Pressure Protective Equipment: A Historical 

Perspective.” 

31 J.T. Webb, and Andrew A. Pilmanis, “Altitude Decompression 

Sickness: Operational Significance,” in Raising the Operational 

Ceiling: A Workshop on the Life Support and Physiological Issues of 

Flight at 60,000 feet and Above, ALlCF-SR-1995-0021, Andrew 

A. Pilmanis, and William J. Sears (eds), December 1995.

32 Kenneth R. King, and Harrison R. Griswold, “Air Force High 

Altitude Advanced Flight Suit Study,” USAFSAM-TR-83-49, 

December 1983.

33 Donn A. Byrnes and Kenneth D. Hurley, Blackbird Rising: 

Birth of an Aviation Legend (Los Lunas, NM: Sage Mesa 

Publications, 1999).

CHAPTER 2

1

 A. Scott Crossfield, Always Another Dawn: The Story of a Rocket 

Test Pilot (Cleveland, OH: World Publishing Co., 1960). Crossfield gives an interesting look at his involvement (which was extensive) in early pressure suit development in the chapter titled, “Girdles, Brassieres, Shattered Sinuses.” It is interesting to note that Joe 

Ruseckas at David Clark Company, who was intimately involved 

in most pressure suit development, credits Crossfield with providing the initial impetus and guidance for all that came later.

2

 Christopher T. Carey, “Supporting Life at 80,000 feet: Evolution 

of the American High Altitude Pressure Suit,” located at 

http://www.lanset.com/aeolusaero/Articles/SSuits.htm. 

3

 Fred M. Sample, Patent 1,272,537 for a “Suit for Aviators,” 

July 16, 1918. Sample applied for the patent on March 20, 1917. 

4

 Lloyd Mallan, Suiting Up For Space: The Evolution of the Space Suit

(New York: The John Day Company, 1971).

5

 “Two Men in a Ball,” Time Magazine, June 8, 1931. 

6

 Name and title confirmed by Gail Fithian, Government 

Documents Department, Boston Public Library, via email, April 

20, 2009. This was confirmed by Mr. John J. Devine, Jr., Reference 

Librarian, Boston Public Library in an email on April 21, 2009, 

“In both the 1933 and 1935 Officials and Employees of the City 

of Boston and County of Suffolk (we were lacking 1934) there is 

a Timothy Leary, M.D., listed as an employee of Suffolk County 

as Medical Examiner for the Southern Division. He was first 

employed by the County in 1908 and assumed his position on the 

18th of March 1931.”

7

 Suiting Up For Space: The Evolution of the Space Suit.

8

 A.E. Boycott, G. C. C. Damant, and J. S. Haldane, “Prevention 

of compressed air illness,” The Journal of Hygiene, Vol. 8, 1908. 

Haldane led an interesting life, and among other things, developed 

the first gas mask in response to German attacks during World War 

I. He also determined the regulation of breathing, discovered the 

Haldane effect in hemoglobin, and founded The Journal of Hygiene.

9

 Suiting Up For Space: The Evolution of the Space Suit.

10 Davis had a long history with Siebe & Gorman, having worked 

for the company since he was 11 years old.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

416

Endnotes: Chapter 2

11 Siebe Gorman & Company Ltd was a British company that advertised itself as “Submarine Engineers.” The partnership of Siebe 

and Gorman was established in 1868 when Augustus Siebe retired 

from the manufacturing business. By that time, he had produced 

hundreds of diving suits and helmets. Henry Siebe, second son 

of Augustus, and his son-in-law William Augustus Gorman established the company as Siebe & Gorman in 1870. Henry Siebe 

died in 1887 and William Gorman died in 1904. In 1905, the 

Vickers Family reformed the company as Siebe Gorman & 

Company, Limited.

12 A history of diving suits located at http://www.divingheritage.com/

siebe.htm.

13 Charles L. Wilson, Physiological Protection of the CSU-4/P High 

Altitude Pressure Suit, (Wright-Patterson AFB: Aerospace Medical 

Research Laboratory, 1962); “Mark Ridge Suit,” located at http://

www.astronautix.com/craft/maresuit.htm. 

14 Suiting Up For Space: The Evolution of the Space Suit.

15 Ibid.

16 The lineage of the United States Air Force is: August 1, 1907– 

July 18, 1914, Aeronautical Division, U.S. Signal Corps; July 18, 

1914–May 20, 1918, Aviation Section, U.S. Signal Corps; 

May 20, 1918–May 24, 1918, Division of Military Aeronautics; 

May 24, 1918–July 2, 1926, U.S. Army Air Service; July 2, 1926– 

June 20, 1941, U.S. Army Air Corps; June 20, 1941–September 

18, 1947, U.S. Army Air Forces (The Air Corps became a subordinate element of the USAAF, and no longer an administrative 

organization, on June 20, 1941. It continued to exist as a combat 

arm of the Army (similar to Infantry) until disestablished by 

Congress with the creation of the U.S. Air Force in 1947.); 

September 18, 1947–Present, United States Air Force.

17 Suiting Up For Space: The Evolution of the Space Suit.

18 Physiological Protection of the CSU-4/P High Altitude Pressure Suit; 

“Mark Ridge Suit,” located at http://www.astronautix.com/craft/ 

maresuit.htm.

19 The Curtiss JN-4 Jenny was a series of biplanes built by the 

Curtiss Aeroplane Company of Hammondsport, New York. The 

common nickname was derived from its Army designation of 

“JN.” The Jenny was produced as a training airplane for the U.S. 

Army and surplus airplanes became the “backbone of American 

post-war aviation” according to Gilles Auliard in “Maiden of the 

Skies,” Air Classics, Vol. 45, No. 4, April 2009.

20 Stanley R. Mohler and Bobby H. Johnson, Wiley Post, His 

Winnie Mae, and the World’s First Pressure Suit (Washington, DC: 

Smithsonian Institution Press, 1971); Suiting Up For Space: The 

Evolution of the Space Suit.

21 Suiting Up For Space: The Evolution of the Space Suit.

22 Walter J. Boyne, Beyond the Horizons: The Lockheed Story 

(New York: St. Martin’s Press, 1998).

23 Ibid.

24 Evan Hadingham, “Wiley Post Flies High,” Invention & Technology Magazine, Spring 2005, Vol. 20, No. 4; Suiting Up For Space: 

The Evolution of the Space Suit.

25 The designated “Round the World” portion of the trip covered 

19,500 miles.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

417

Endnotes: Chapter 2

26 “Wiley Post,” located at http://en.wikipedia.org/wiki/Wiley_Post; 

“Post and Settle Win Flying Prizes; Gain Harmon International 

Trophies for 1933 for World and Stratosphere Flights,” New York 

Times, April 22, 1934.

27 The company took its name from a combination of his first and 

last name. Robertson died in 1945, and in 1967, his heirs sold 

the company to Cadbury’s that, in 1969, merged with Schweppes 

Australia to become Cadbury Schweppes. 

28 This was generally referred to as the “MacRobertson” race, a contraction of the name of the Australian benefactor. An excellent 

history of this unique race is provided by Arthur Swinson in The 

Great Air Race, originally published in 1934, but republished by 

Littlehampton Book Services, Ltd. In August 1968.

29 Stanley R. Mohler and Bobby H. Johnson, Wiley Post, His Winnie 

Mae, and the World’s First Pressure Suit (Washington, DC: Smithsonian Institution Press, 1971), Post quote from p. 71.

30 Tom D. Crouch, The Eagle Aloft (Washington, DC: Smithsonian 

Institution Press, 1983); Nick Moehlmann. “John Wise, A 

Pioneer,” John Wise Balloon Society of Central Pennsylvania, 

located at http://www.johnwise.net/jw.html

31 Suiting Up For Space: The Evolution of the Space Suit, Post quote 

is on p. 26.

32 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.

33 Charles L. Wilson, “Wiley Post: First Test of High Altitude 

Pressure Suits in the United States,” Archives of Environmental 

Health, Vol. 10, May 1965.

34 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit; 

Suiting Up For Space: The Evolution of the Space Suit.

35 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit. 

Apparently, the $75 was Hucks’ original estimate of the cost; in 

a rare case of an underun in the aviation business, the actual cost 

has been reported as $60.

36 Suiting Up For Space: The Evolution of the Space Suit.

37 W.F. Craven and J.L. Cate (eds), “The Army Air Forces in World 

War II,” Chapter VII, located at http://www.ibiblio.org/hyperwar/

AAF/VII/AAF-VII-13.html; The upright, cylindrical cork-lined 

chamber was later used as a food-storage bin for animals. During 

World War II, it was moved to the Air Force School of Aviation 

Medicine in San Antonio, Texas, and reactivated. It is presently in 

the Aeromedical Museum at Brooks AFB.

38 “Post Tests Flying Suit,” The Cleveland News, 14 July 1934; Charles 

L. Wilson, “Wiley Post: First Test of High Altitude Pressure Suits 

in the United States,” Archives of Environmental Health, Vol. 10, 

May 1965.

39 A biography of Colley located at http://www.ohiohistorycentral.org/

entry.php?rec=2633

40 William M. Leary, We Freeze to Please: A History of NASA’s Icing 

Research Tunnel and the Quest for Flight Safety, NASA SP-2002-

4226 (Washington, DC: NASA, 2002).

41 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

418

Endnotes: Chapter 2

42 “Wiley Post: First Test of High Altitude Pressure Suits in the 

United States.” 

43 The race was won by a DeHaviland DH.88 Comet at an average 

speed of 171 mph, and Douglas DC-2 and Boeing 247 transports 

took second and third place, respectively. All 3 winners were 

twin-engine aircraft.

44 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.

45 Ibid.

46 Francis G. Nesbit, “Test of Oxygen Pressure Flying Suit for High 

Altitude Flying,” Wright Field Report 1-54-458, September 1934.

47 Ibid.

48 Lauren D. Lyman, “World’s Fair Flight,” New York Times, 

September 6, 1934.

49 Suiting Up For Space: The Evolution of the Space Suit; Wiley Post, 

His Winnie Mae, and the World’s First Pressure Suit.

50 Parker was one of the true characters in early aviation. He built his 

own airplane when he was young, flying before December 17, 1916, 

which gave him the privilege of being a member of the Early Birds. 

He invented the variable-pitch propeller, joined Pershing in Mexico, 

and managed the Phillips Petroleum Company corporate aviation 

organization. See http://www.earlyaviators.com/eparker.htm

51 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.

52 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit; 

Physiological Protection of the CSU-4/P High Altitude Pressure Suit.

53 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.

54 In 1957, Transcontinental and Western Airlines became Trans 

World Airlines.

55 Wiley Post, His Winnie Mae, and the World’s First Pressure Suit.

56 Evan Hadingham, “Wiley Post Flies High,” Invention & Technology Magazine, Spring 2005, Vol. 20, No. 4.

57 Ibid.

58 Physiological Protection of the CSU-4/P High Altitude Pressure Suit.

59 The word “record” is used freely by most publications and is 

frequently, technically, incorrect. A world record exists only if 

it meets certain criteria and is submitted to, and ratified by, the 

Fédération Aéronautique Internationale (FAI). Mr. Marcel Meyer, 

Executive Officer for Records at the FAI, was kind enough to send 

the altitude-record database for the 1930s to confirm the data presented in this chapter.

60 T.W. Walker, “The Development of the Pressure Suit for HighAltitude Flying, The Project Engineer, Vol. 15, No. 5, May 1956; 

Stuart Nixon, “Moments & Milestones: Ten Most Wanted,” 

Air & Space Magazine, September 2002, located at http://www.

airspacemag.com/flight-today/Ten_Most_Wanted.html; “Pezzi Suit,” 

located at http://www.astronautix.com/craft/pezisuit.htm

61 Kalikiano Kalei, “A History of US Military Aviation Oxygen 

Systems to 1945,” located at http://www.authorsden.com/visit/ 

viewarticle.asp?id=36665

62 Suiting Up For Space: The Evolution of the Space Suit.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

419

Endnotes: Chapter 2

63 “The Outlook: A Running Commentary on Air Topics,” Flight, 

7 January 1937; the FAI record database at http://records.fai.org/

pilot.asp?from=general_aviation&id=4416; The FAI records show 

Hilsz climbed to 14,310 meters an Détré to 14,843 meters. Both 

were in the Class C Landplane category.

64 “Garsaux Suit,” located at http://www.astronautix.com/craft/ 

garxsuit.htm

65 “Translation of a Report on Development of a Pressure Suit,” 

USAAF Engineering Division Report TSRAL-3-660-48-M, 

August 11, 1945; The History of Dräger (Lübeck, Germany: 

Dräger, 2008).

66 “Translation of a Report on Development of a Pressure Suit.” 

67 Ibid. 

68 “Translation of a Report on Development of a Pressure Suit;” 

Suiting Up For Space: The Evolution of the Space Suit. 

69 “Translation of a Report on Development of a Pressure Suit.” 

70 In this use, “plexiglass” (not capitalized and ending is “ss”) is a 

generic term for a variety of acrylic thermoplastic materials. 

The standard Plexiglas (capitalized with only a single “s”) nomenclature will be used for the specific material covered by the 

Rohm and Haas Company trademark.

71 “Translation of a Report on Development of a Pressure Suit.” 

72 Ibid.

73 Ibid.

74 “Escafandra Estratonautica, “located at http://www.astronautix.com/

craft/escutica.htm.

75 Ibid.

76 Helen W. Schulz, “Case History of Pressure Suits,” Air Materiel 

Command, May 1951; Suiting Up For Space: The Evolution of the 

Space Suit.

77 Most modern texts list Swain as “F.R.D.,” but a Time Magazine

article, “Ferdie’s Flight,” in the October 12, 1936, issue says it 

should be “F.D.R.” so that is what is used here.

78 The FAI lists this as 15,223 meters.

79 “Case History of Pressure Suits;” Physiological Protection of the 

CSU-4/P High Altitude Pressure Suit; C.H. Barnes, Bristol Aircraft 

Since 1910 (London: Putnam, 1964).

80 Owen Thetford, Aircraft of the Royal Air Force 1918-57, 1st edition 

(London: Putnam, 1957); the FAI lists this as 16,440 meters.

81 H.G. Armstrong (ed.), Aerospace Medicine (Baltimore: The 

Williams and Wilkins Co., 1961).

82 “A History of Mitchel Field” from the The Cradle of Aviation 

Museum, located at http://www.cradleofaviation.orglhistory/ 

airfields/mitchel.html; Green Peyton Wertenbaker, Fifty Years 

of Aerospace Medicine, AFSC Historical Publications, Series 

No. 67-180 (Brooks AFB, Texas: USAF, 1968). 

83 Charles A. Dempsey, Air Force Aerospace Medical Research Laboratory: 50 Years of Research on Man in Flight (Wright-Patterson AFB, 

OH: U.S. Air Force, 1985).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

420

Endnotes: Chapter 2

84 “Oral History Interview: Major General Harry G. Armstrong 

(Ret),” 1981.

85 “Biography of Major General Otis O. Benson, Jr.,” located at 

http://www.Af.millbioslbio_ 4669.shtml.

86 “Case History of Pressure Suits.” 

87 Ibid.

88 Contract W535-ac-17000, purchase order 41-4291, November 29, 

1940; Christopher T. Carey, “Supporting Life at 80,000 feet: 

Evolution of the American High Altitude Pressure Suit.”

89 “Case History of Pressure Suits.” This suit was originally designated 

Model 1-E by the Army but soon became the Type 3.

90 Ibid. These suits were initially designated Type A (altitude) and 

Type G (gravity).

91 Contract W535-ac-18048, purchase order 41-4891 of 

19 December 1940 and 41-6967 of February 18, 1941.

92 “Case History of Pressure Suits.” 

93 Ibid.

94 Ibid.

95 Letter, Lt. Col. F.O. Carroll, Chief, Experimental Engineering 

Section, to Naval Aircraft Central District, June 16, 1941.

96 Contract W535-ac-21580, purchase order 42-3155, 

September 25, 1941.

97 Interoffice Memorandum, Maj. J.W. Sessums, Jr., to Chief, Experimental Engineering Section, October 16, 1941, subject: Visit to 

Boeing in Seattle, Washington; “Case History of Pressure Suits.” 

98 Biography of John D. (Janis) Akerman, located at http://latvianaviation.com/BC_Akerman.html

99 John D. Akerman, “Report on Development Work on Low 

Differential Pressure Suit for High Altitude Flying, BABM Model 

(Boeing, Akerman, Bell, Mayo),” Strato Equipment Company 

Report, March 22, 1943.

100 USAAF Memorandum Report No. EXP-M-54-660-11F, 

“Conference at Boeing Aircraft Company on Oxygen Equipment, 

14-19 January 1942,” February 3, 1942.

101 “Case History of Pressure Suits.” 

102 USAAF Memorandum Report No. EXP-M-54-660-11M, 

“Pressurized Altitude Suits and Accessory Equipment,” July 10, 

1942; Contract W535-ac-31183, purchase order 43-1024E, 

16 July 1942 (Goodyear had started development and production 

of the suits based on a letter contract issued in February 1942, 

hence the ability to deliver by August 1.)

103 LaBRRRatory,” Boeing Magazine, February 1942.

104 John D. Akerman, “Report on Development Work on Low 

Differential Pressure Suit for High Altitude Flying, BABM Model 

(Boeing, Akerman, Bell, Mayo),” Strato Equipment Company 

Report, March 22, 1943.

105 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

421

Endnotes: Chapter 2

106 Contract W535-ac-24833 purchase order 42-10239 dated 

January 20, 1942, for B.F. Goodrich and Contract 

W535-ac-24845 purchase order 42-10285 dated January 20, 

1942, for U.S. Rubber. 

107 “Case History of Pressure Suits.” 

108 Letter, Bell Aircraft Corporation to Assistant Chief, Materiel 

Division, October 9, 1941; Contract W535-ac-24203, purchase 

order 42-6580, February 7, 1942; Letter, Bell Aircraft to 

Contracting Officer, February 21, 1942, Subject: Contract 

W535-ac-24203.

109 USAAF Memorandum Report No. EXP-M-54-660-11H, 

“Conference at National Carbon Company on Pressure Suit, Vinylite, Double Layer, February 13, 1942,” February 21, 1942.

110 USAAF Memorandum Report No. EXP-M-54-660-11K, “Conferences on Altitude and Anti-Blackout Suits,” April 15, 1942.

111 “Case History of Pressure Suits.” 

112 John D. Akerman, “Report on Development Work on Low 

Differential Pressure Suit for High Altitude Flying, BABM Model 

(Boeing, Akerman, Bell, Mayo),” Strato Equipment Company 

Report, March 22, 1943.

113 Ibid; USAAF Memorandum Report No. EXP-M-54-660-11O, 

“High Altitude Flying Suits and Accessory Equipment,” August 8, 

1942; Letter, Bell Aircraft Corporation to Assistant Chief, 

Materiel Division, October 9, 1941; Contract W535-ac-24203, 

purchase order 42-6580, February 7, 1942; Letter, Bell Air 

craft to Contracting Officer, February 21, 1942, Subject: 

Contract W535-ac-24203

114 J “Report on Development Work on Low Differential Pressure 

Suit for High Altitude Flying, BABM Model (Boeing, Akerman, 

Bell, Mayo).” 

115 Ibid.

116 In early 1941, the Experimental Engineering Section of the U.S. 

Army Air Corps Materiel Division (soon reorganized as a part of 

the new USAAF Air Materiel Command) began to assign “MX” 

(for “Materiel, Experimental”) designators to many of its research 

and development (R&D) projects. Issued by the security office, 

these designators provided a non-descript means of identifying 

new R&D programs in engineering orders, correspondence, and 

procurement contracts. Not all MX numbers resulted in hardware: 

MX designations were generally assigned very early in a project’s 

evolution, and thus many MX numbers were subsequently cancelled or closed out without producing anything more than a 

research Report.

117 Project Report, “R&D Projects of the Experimental Engineering 

Section, Materiel Command, Pressure Suits and Anti-Blackout 

Suits,” July 1, 1942.

118 Charles C. Lutz and John W. Heim, “Standardization of Altitude 

Suits, Types T-1 and S-1,” USAF Technical Memorandum Report 

WCRD-52-121, SEO-660-141, November 20, 1952.

119 “Case History of Pressure Suits,” p. 12, quoting Harold Lamport 

in “Studies on the Problem of Acceleration in Aviation Medicine,” 

July 31, 1942.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

422

Endnotes: Chapter 2

120 USAAF Memorandum Report No. EXP-M-54-660-11O, “High 

Altitude Flying Suits and Accessory Equipment,” August 8, 1942; 

Ward T. Van Orman, “Zipper,” U.S. Patent 2,371,776, March 20, 

1945; Ward T. Van Orman, “Structure,” U.S. Patent 2,391,282, 

December 18, 1945.

121 “Case History of Pressure Suits.” 

122 Ibid.

123 “Aeronautics and Astronautics Chronology, 1940-1944,” located 

at http://www.hq.nasa.gov/office/pao/History/Timeline/1940-44.html.

124 USAAF Memorandum Report No. EXP-M-54-660-11Q, “Flights 

in B-17E Aircraft by Crew Using Pressurized High Altitude Pilot 

Suit and Equipment,” October 30, 1942.

125 “Case History of Pressure Suits.” 

126 “Report on Development Work on Low Differential Pressure 

Suit for High Altitude Flying, BABM Model (Boeing, Akerman, 

Bell, Mayo).” 

127 Ibid.

128 Shelby L. Stanton, Combat Uniforms of World War II

(Mechanicsburg, PA: Stackpole Books, 1995).

129 USAAF Memorandum Report No. EXP-M-54-660-11T, “Test 

Flights of High Altitude Pilot Suits and Accessory Equipment,” 

January 2, 1943.

130 “Case History of Pressure Suits.” 

131 USAAF Memorandum Report No. EXP-M-54-660-11X, 

“Pressure Suit—Type BABM,” April 21, 1943; “A Tribute to John 

D. Akerman,” located at http://www.aem.umn.edu/info/history/ 

akerman.shtml

132 USAAF Memorandum Report No. EXP-M-54-660-11V, “Flight 

Test High Altitude Pilot Suits and Accessories,” February 25, 1943.

133 C.G. Sweeting, Combat Flying Equipment: U.S. Army Aviator’s 

Personal Equipment, 1917–1945 (Washington, DC: Smithsonian 

Institution Press, 1989).

134 “Case History of Pressure Suits.” 

135 “Case History of Pressure Suits;”; Ward T. Van Orman, “Structure,” 

U.S. Patent 2,401,990, June 11, 1946.

136 W. E. Scott and L.W. Meakin, “Report on Test of Pressure Suit, 

High Altitude, U.S. Rubber Company,” Aeronautical Materials 

Section Report AMS(M)-685, March 12, 1943.

137 Ibid.

138 LCDR Donald W. Gressly (MC) and L.W. Meakin, “Report 

on High Altitude Pressure Suit—Goodrich Rubber Company—

Model 5E,” Aeronautical Materials Laboratory Report AML(M)-

763, August 13, 1943.

139 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

423

Endnotes: Chapter 2

140 LCDR Donald W. Gressly (MC) and L.W. Meakin, “Report on 

High Altitude Pressure Suit—John D. Akerman,” Aeronautical 

Materials Laboratory Report NAF-2597, Part II, October 10, 

1943; “Report on Development Work on Low Differential 

Pressure Suit for High Altitude Flying, BABM Model (Boeing, 

Akerman, Bell, Mayo).” 

141 “Report on High Altitude Pressure Suit—John D. Akerman;” 

“Report on Development Work on Low Differential Pressure 

Suit for High Altitude Flying, BABM Model (Boeing, Akerman, 

Bell, Mayo).” 

142 “Report on High Altitude Pressure Suit—John D. Akerman;” 

“Report on Development Work on Low Differential Pressure 

Suit for High Altitude Flying, BABM Model (Boeing, Akerman, 

Bell, Mayo).” 

143 “Report on High Altitude Pressure Suit—John D. Akerman.” 

144 LCDR Donald W. Gressly (MC) and L.W. Meakin, “Report 

on Pressure Suit—High Altitude—Goodyear Tire & Rubber 

Co.,” Aeronautical Materials Laboratory Report NAF-2597, 

September 31, 1943.

145 Ibid.

146 LCDR Donald W. Gressly (MC) and L.W. Meakin, “Report 

on High Altitude Pressure Suit—General Electric Co.,” 

Aeronautical Materials Laboratory Report NAM-2597, Part III, 

January 22, 1944.

147 Ibid.

148 Ibid.

149 Confidential letter to BuAer from R.J.H. Conn, supervisor of the 

Aeronautical Materials Laboratory, 27 January 1944.

150 Ibid.

151 Letter, Maj. Gen. C.E. Branshaw, Commanding, Headquarters Air 

Materiel Command, to Decorations and Awards Branch, USAAF, 

Washington, 10 January 1944.

152 “Case History of Pressure Suits.” 

153 Ibid. 

154 Ibid.

155 Air Force Technical Report No 5769, “The Development of High 

Altitude Oxygen Helmets,” March 1949.

156 Ibid.

157 Time Magazine online archives, located at http://www.time.com/

time/magazine/article/0,9171,776012,00.html

158 “Flyers’ Flexible Strato-Suit Sustains Life at 15-Mile Heights,” 

Popular Mechanics Magazine, November 1945, online archive 

located at http://books.google.com/books.

159 Always Another Dawn: The Story of a Rocket Test Pilot, quote on 

p. 237.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

424

Endnotes: Chapter 3

CHAPTER 3

1

 George W. Crile, Blood-pressure in Surgery (Philadelphia: J.B. 

Lippincott Co., 1903).

2

 George W. Crile, George Crile: An Autobiography, Grace Crile, ed. 

(Philadelphia: J.B. Lippincott Co., 1947); Wilfrid H. Brooke, 

“The Anti-G Suit: A link between clinical surgery and aviation 

medicine,” a paper presented at the Aerospace Medical Association, 

Alaska, May 3, 2004.

3

 Thurston was the first man to become a Doctor of Science in 

Aeronautical Engineering at Imperial College. In typically 

British sense, he was, formally, Dr. A. P. Thurston, M.B.E., 

D.Sc, M.I.Mech.E., F.R.Ae.S.

4

 Norman Berlinger, “The War Against Gravity,” Invention & 

Technology Magazine, Spring 2005, Vol. 20, No. 4.

5

 The pluralized name derives from each car representing a separate 

“flying machine.”

6

 The Earls Court of 1904 bore no resemblance to the Earls Court 

Exhibition Centre that was built in the same location during 1935, 

or the much later facility built in the 1980s. Nevertheless, the late 

19th Century site was home to Buffalo Bill’s Wild West Show and 

a 300-foot high observation (Ferris) wheel in addition to Maxim’s 

Flying Machines.

7

 A biography of Sir Hiram Maxim, located at http://www.

s104638357.websitehome.co.uk/html/birthday_maxim_01.htm.

8

 Henry Head, “The sense of stability and balance in the air,” in 

H. Milford (ed.), The Medical Problems of Flying (London: Oxford 

University Press, 1920).

9

 Henry R. Palmer Jr., The Story of the Schneider Trophy Race 

(Seattle: Superior Publishing Co., 1962).

10 Siegfried Ruff & Hubertus Strughold, Compendium of Aviation 

Medicine (Ottawa: Alien Property, 1942). Discussions of acceleration will use the Aerospace Medical Association convention. References to the standard gravitational acceleration of Earth will use 

the lowercase “g.” References to acceleration acting on objects and 

crewmembers in multiples of Earth’s gravitational acceleration will 

use the uppercase “G.”

11 John P. Stapp, “Biodynamics: the Key to Flight,” Aviation, Space, 

and Environmental Medicine, 1986, Vol. 57.

12 George Smith, “The Franks Flying Suit in Canadian Aviation 

Medicine History, 1939-1945,” Canadian Military History, 

Vol. 8, No. 2, Spring 1999; Aeromedical Training for Flight 

Personnel, Army FM 3-04.301 (formerly FM 1-301) 

(Washington, DC: U.S. Army, 2000).

13 Compendium of Aviation Medicine.

14 J.E. Whinnery and B.S. Shender, “The opticogravic nerve: eyelevel anatomic relationships within the central nervous system,” 

Aviation, Space, and Environmental Medicine, 1993, Vol. 63. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

425

Endnotes: Chapter 3

15 Cone cells are photoreceptors in the retina that function best in 

relatively bright light. The cone cells gradually become sparser 

toward the periphery of the retina. Cones are less sensitive to 

light than the rod cells in the retina (which support vision at low 

light levels), but allow color perception. They are also able to perceive finer detail and more rapid changes in images because their 

response times are faster than those of rods.

16 W.B. Albery, “Acceleration in other axes affects +gz

 tolerance: 

dynamic centrifuge simulation of agile flight,” Aviation, Space, 

and Environmental Medicine, 2004, Vol. 75. 

17 N.D. Green, “Acute soft tissue neck injury from unexpected 

acceleration,” Aviation, Space, and Environmental Medicine, 

2003, Vol. 74. 

18 J. Rieser and H. Pick, “The perception and representation of 

human locomotion,” in W. Prinz and B. Hommel (eds.), Common 

Mechanisms in Perception and Action (New York: Oxford, 2000).

19 Erasmus Darwin, Zoonomia; or, The Laws of Organic Life (London: 

J. Johnson, 1792); Republished by Echo Library, June 2007.

20 William J. White, A History of the Centrifuge in Aerospace Medicine

(Long Beach, CA: Douglas Aircraft, 1964).

21 Ibid.

22 H.G. Armstrong and J.W. Heim, “The Effects of Acceleration on 

the Living Organism,” December 1, 1937.

23 Armstrong biography, located at http://www.state.sd.us/military/

VetAffairs/sdwwiimemorial/SubPages/stories/story11.htm; 

Armstrong biography at http://www.state.sd.us/military/VetAffairs/

sdwwiimemorial/SubPages/stories/story11.htm.

24 Ibid. In 1939 the organization was renamed the Aeromedical 

Research Unit, becoming the Aero Medical Research Laboratory 

in 1942 and the Aero Medical Laboratory later that same year. 

It became the Aerospace Medical Laboratory in 1959, and the 

Aerospace Medical Division (of ARDC) later that same year. In 

1979 it was redesignated the Air Force Aerospace Medical 

Research Laboratory, and in 1985, the Harry G. Armstrong 

Aerospace Medical Laboratory.

25 Ibid.

26 Biography of Maj. Gen. Harry George Armstrong, located at 

http://www.af.mil/information/bios/bio.asp?bioID=4547

27 Armstrong obituary, The Physiologist, Vol. 27, No. 1, 1984.

28 R.W. Bancroft, J.E. Dunn (eds), “Experimental Animal 

Decompression to a Near Vacuum Environment,” Report 

SAM-TR-65-48 (Brooks AFB, TX: USAF School of Aerospace 

Medicine, June 1965).

29 Wilfrid H. Brook, “The Development of the Australian Anti-G 

Suit,” Aviation, Space, and Environmental Medicine, February 

1990. My thanks to Mr. Brook for sharing his research and insight 

into the G-suit development Down Under.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

426

Endnotes: Chapter 3

30 Banting received the Nobel Prize for Medicine in 1923 along with 

Professor John J.R. MacLeod, also of the University of Toronto, 

for the discovery of insulin. Charles H. Best assisted Banting, who 

ultimately shared his prize money with the young man. Best succeeded Macleod as professor of physiology at university in 1929.

31 “History of Defence R&D Canada” located at http://www.drdc-rddc.

gc.ca/about-apropos/milestones-grandeetapes-eng.asp

32 Franks biography, located at http://www.utoronto.ca/bantresf/HallofFame/Franks.html.

33 “History of Defence R&D Canada.” 

34 William J. White, A History of the Centrifuge in Aerospace Medicine

(Long Beach, CA: Douglas Aircraft, 1964); “Aviation Medicine 

Begins in Canada,” factsheet by the Canadian Space Agency.

35 “Aviation Medicine Begins in Canada,” factsheet by the Canadian 

Space Agency.

36 Norman Berlinger, “The War Against Gravity,” Invention & 

Technology Magazine, Spring 2005, Vol. 20, No. 4.

37 Ibid.

38 Maj. Gen. David N. W. Grant, “An Explanation of Pilot Blackout and the Evolution of Preventive Equipment: Clothes Make 

the Superman,” in The Story of the G-Suit (New Haven, CT: The 

Berger Brothers Company, 1946).

39 David M. Clark, “The E.J. Baldes I Knew,” an essay in the informal autobiography of David Clark (Worcester, MA: David Clark 

Company, 1992).

40 R. E. Gadolin, Aviation Medicine Research: A Historical Review, 

NAMRL Special Report 92-3 (NAS Pensacola, FL: Naval 

Aerospace Medical Research Laboratory, 1992).

41 A History of the Centrifuge in Aerospace Medicine.

42 Ibid.

43 “Johnsville Centrifuge Gondola Returns Home to a New Museum,” 

spaceref.com, May 15, 2011.

44 The Aeronautics Branch of the Department of Commerce regulated the aviation industry at the time. Dr. Bauer also founded the 

Aerospace Medical Association in 1929.

45 A History of the Centrifuge in Aerospace Medicine.

46 C.G. Sweeting, Combat Flying Equipment: U.S. Army Aviator’s 

Personal Equipment, 1917–1945 (Washington, DC: Smithsonian 

Institution Press, 1989). 

47 “The E.J. Baldes I Knew;” Stanley N. Roscoe, “From the Roots 

to the Branches of Cockpit Design,” located at http://www.aero.

ca/News2_94.html; Joseph S. Ames, Aircraft Accidents Method of 

Analysis (Langley, VA: NACA, 1928).

48 E.H. Wood, E.H. Lambert, E.J. Baldes, and C.F. Code, “Effects 

of Acceleration in Relation to Aviation,” Federal Proceedings, 1946, 

Vol. 5.

49 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

427

Endnotes: Chapter 3

50 Ibid. The plot of the movie was custom-made for this chapter on 

g-suits: “A military surgeon teams with a ranking navy flyer to 

develop a high-altitude suit which will protect pilots from blacking out when they go into a steep dive” according to the Internet 

Movie Database located at http://www.imdb.com/title/tt0033537/

51 J.F. Fulton, Aviation Medicine in its Preventive Aspects: An Historical Survey (London: Oxford University Press, 1948).

52 George Crile: An Autobiography.

53 The committee was later absorbed into what became the current 

National Academies of Science. A list of committees and their 

chairmen is maintained by the National Academies at http://www7.

nationalacademies.org/archives/roster_advcomssurgeons.html

54 George Crile: An Autobiography.

55 This reference provided by Dr. Jan Stepanek at the Mayo Clinic 

as significant. Unfortunately, I do not read German, and am 

including the reference for those who can. Dr. Siegfried Ruff and 

Dr. Hubertus Strughold, Grundriss der Luftfahrtmedizin, 1939.

56 J.F. Fulton, Aviation Medicine in its Preventive Aspects: An Historical Survey (London: Oxford University Press, 1948). 

57 “The War Against Gravity.” 

58 Aviation Medicine in its Preventive Aspects: An Historical Survey. 

Stewart was killed on June 22, 1941, during a high-altitude 

physiological research flight aboard a Boeing Flying Fortress 

Mk I (B-17C).

59 Obituary for Spencer Merriam Berger, located at http://www.

nytimes.com/2002/01/29/classified/paid-notice-deaths-berger-spencermerriam.html.

60 Frank S. Cotton, “An aerodynamic suit for the protection of 

pilots against black-out,” The Australian Journal of Science, 1945, 

Vol. VII.

61 “The Development of the Australian Anti-G Suit.” 

62 Ibid.

63 Ibid.

64 The acronym was always written with the “full stops” (periods).

65 Australian Academy of Science Biographical Memoirs of Archibald 

Keverall McIntyre, 1913–2002, located at http://www.science.org.

au/academy/memoirs/mcintyre.htm; “The Development of the Australian Anti-G Suit;” “An Explanation of Pilot Blackout and the 

Evolution of Preventive Equipment: Clothes Make the Superman.” 

66 Combat Flying Equipment: U.S. Army Aviator’s Personal Equipment, 

1917–1945.

67 Banting received the Nobel Prize for Medicine in 1923 along with 

Professor John J.R. MacLeod, also of the University of Toronto, 

for the discovery of insulin. Charles H. Best assisted Banting, who 

ultimately shared his prize money with the young man. Best succeeded Macleod as professor of physiology at university in 1929.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

428

Endnotes: Chapter 3

68 Peter Allen, “The Remotest of Mistresses—The Story of Canada’s 

Unsung Tactical Weapon: The Franks Flying Suit,” Canadian 

Aviation Historical Society Journal, Winter 1983.

69 “DRDC Toronto,” located at http://en.wikipedia.org/wiki/DRDC_

Toronto.

70 “The Remotest of Mistresses.”

71 “DRDC Toronto.” 

72 Franks biography located at http://www.utoronto.ca/bantresf/ 

HallofFame/Franks.html.

73 “Aviation Medicine Begins in Canada,” factsheet by the Canadian 

Space Agency.

74 “The R.C.A.F. Human Centrifuge and Acceleration Laboratory,” The Journal of the Canadian Medical Services, Vol. 4, No. 1, 

November 1946.

75 “Progress Report on Work to Protect Personnel Against The 

Pressure Effects of Acceleration,” Hall Papers.

76 “Aviation Medicine Begins in Canada,” factsheet by the Canadian 

Space Agency.

77 “Proceedings of an Informal Meeting of the Group Interested 

in Aviation Medical Research,” Hall Papers.

78 “Progress Report on Work to Protect Personnel Against the 

Pressure Effects of Acceleration.” 

79 George Smith, “The Franks Flying Suit in Canadian Aviation 

Medicine History, 1939-1945,” Canadian Military History, Vol. 8, 

No. 2, Spring 1999.

80 “Progress Report on Work to Protect Personnel Against the 

Pressure Effects of Acceleration.” 

81 Siegfried Ruff and Hubertus Strughold, Compendium of Aviation 

Medicine (Ottawa: Alien Property, 1942).

82 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman.” 

83 “Influence of Tangential Forces on the Human Organism,” Bulletin 

of War Medicine, July 1942; “The Franks Flying Suit in Canadian 

Aviation Medicine History, 1939-1945.” 

84 “Aviation Medicine Begins in Canada.” Located near Ontario, 

Camp Borden is the historic birthplace of the Royal Canadian Air 

Force. The current CFB Borden is the largest training facility in 

the Canadian Forces.

85 “The Development of the Australian Anti-G Suit.” 

86 “About Defence R&D Canada,” located at http://www.drdc-rddc.

gc.ca/about-apropos/milestones-grandeetapes-eng.asp; “The Remotest 

of Mistresses.”

87 “Report on Practical Flying Tests Carried Out With ‘Special Flying 

Suit,’” RAE Report C-2830, June 5, 1941.

88 “The R.C.A.F. Human Centrifuge and Acceleration Laboratory,” 

The Journal of the Canadian Medical Services, Vol. 4, No. 1, 

November 1946.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

429

Endnotes: Chapter 3

89 “Report on Hydrostatic Suit,” RAE Report C-2833, June 29, 1941.

90 “Tactical Trials with Hydrostatic Flying Suit,” RAE Report C-2837, 

August 21, 1941.

91 “Interim Report on Franks Suit Trials at No.43 Squadron,” RAE 

Report C-2842, June 8, 1942. 

92 “The War Against Gravity.” 

93 “The Development of the Australian Anti-G Suit.” 

94 “The Remotest of Mistresses.”

95 Edgar C. Black, History of the Associate Committee on Aviation 

Medical Research: 1939-1945 (Ottawa: NRC, 1946).

96 Mike Spick, The Ace Factor (New York: Avon, 1989).

97 Comments from Dr. Jan Stepanek at the Mayo Clinic on a draft 

copy of this manuscript, February 27, 2010.

98 T.M. Gibson and M.H. Harrison, Into Thin Air: A History of 

Aviation Medicine in the RAF (London: Robert Hale, 1984).

99 George L. Maison, Clarence A. Maaske, G.A. Hallenbeck and 

E.E. Martin, “Acceleration and the G Suit,” Air Surgeon’s Bulletin 

(January 1945).

100 Franks biography, located at http://www.utoronto.ca/bantresf/ 

HallofFame/Franks.html.

101 “The R.C.A.F. Human Centrifuge and Acceleration Laboratory,” 

The Journal of the Canadian Medical Services, Vol. 4, No. 1, 

November 1946.

102 Helen W. Schulz, “Case History of Pressure Suits,” Air Materiel 

Command, May 1951; Vannevar Bush biography in Current 

Biography 1947.

103 Letter, Dr. Vannevar Bush, Chairman NACA, to Maj. Gen. H.H. 

Arnold, Chief, Army Air Corps, October 31, 1940.

104 Email, Dr. Jan Stepanek to Dennis R. Jenkins, March 1, 2010; 

Norman Berlinger, “The War Against Gravity,” Invention & 

Technology Magazine, Spring 2005, Vol. 20, No. 4.

105 National Aeronautic Association, “Collier Trophy Winners,” 

located at http://naa.aero/html/awards/index.cfm?cmsid=158.

106 Obituary, “Charles Code, 87, Leader in Allergy Research,” 

New York Times, December 12, 1997.

107 “The E.J. Baldes I Knew.” 

108 The military designated this as the A-8 mask. The A-8 was a 

constant-flow mask that replaced the A-7 oral-nasal mask. It contained a rebreathing reservoir to provide oxygen enrichment. 

The A-8 mask was used in most 1930s Army aircraft, but was 

rather quickly replaced by A-9, A-10, and A-14 diluter demand 

type oxygen masks.

109 Email, Dr. Jan Stepanek, March 1, 2010; Stephanie Nolen, 

Promised the Moon (Jackson, TN: Basic Books, 2004).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

430

Endnotes: Chapter 3

110 “Pathfinders: Arthur H. Bulbulian,” Mayo Magazine, Winter 1994.

111 “The Tradition and Heritage of the Mayo Clinic,” located at http://

www.mayoclinic.org/tradition-heritage/

112 “The War Against Gravity.” 

113 Ibid.

114 Ibid.

115 Ibid.

116 Email from Ivy Leaf, who maintains a website dedicated to corsets 

at http://www.corsetiere.net.

117 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman.” 

118 J.F. Fulton, Aviation Medicine in its Preventive Aspects: An Historical Survey (London: Oxford University Press, 1948). 

119 Obituary for Spencer Merriam Berger, located at http://www.

nytimes.com/2002/01/29/classified/paid-notice-deaths-berger-spencermerriam.html.

120 The Story of the G-Suit (New Haven, CT: The Berger Brothers 

Company, 1946).

121 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman.” 

122 “The E.J. Baldes I Knew.” 

123 “An Explanation of Pilot Blackout and the Evolution of Preventive Equipment: Clothes Make the Superman.” The designations 

of g-suits had some logic behind it, with the Army and Air Force 

suits using a “G” and the Navy suits using “Z.” However, not all 

suits procured in the early days (such as the initial Berger Brother 

suits ordered for use in the Pacific) carried military designations, 

and frequently identical suits carried different Air Force and Navy 

designations. In addition, the Navy frequently used Army suits 

and vice-versa. Nevertheless, this was considerably better than the 

designation system later adopted for pressure suits and helmets 

that made little, if any, sense.

124 “Anti-Blackout Suit Development,” David Clark Company Report 

under contract NOa(s)-8258, June 28, 1946; “An Explanation 

of Pilot Blackout and the Evolution of Preventive Equipment: 

Clothes Make the Superman.” 

125 “Spencer Gradient Pressure Anti-Blackout Equipment: Gradient 

Pressure Valve—Operation, Installation, and Adjustment,” the 

Berger Brothers Company, May 1943.

126 “Operation of Spencer Gradient Pressure Anti-Blackout Suit,” 

The Berger Brothers Company, May 1943.

127 Ibid.

128 “The E.J. Baldes I Knew.” 

129 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman.” At some point during 

the 1950s, the “Air” in NACEL was changed to “Aerospace.”
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

431

Endnotes: Chapter 3

130 C.A. Maaske, G.A. Hallenbeck, and EE. Martin, “Evaluation of 

Anti-G Suits,” National Research Council, Division of Medical 

Sciences, Report No. 348, June 10, 1944.

131 The Story of the G-Suit; “Anti-Blackout Suit Development.” 

132 G.L. Maison, “Evaluation of Anti-G Suits, Report No. 5,” Aero 

Medical Laboratory Memorandum Report No. ENG-49-696-

51E-1, 11 August 1944. This status was changed to “substitute 

standard” on 14 August 1944 when the improved G-3 g-suit 

was standardized. The Army declared the G-1 suit obsolete on 

May 21, 1945, and the G-2 became obsolete on April 10, 1946.

133 “The E.J. Baldes I Knew.” 

134 A. Scott Crossfield, Always Another Dawn: The Story of a Rocket 

Test Pilot (Cleveland, OH: World Publishing Co., 1960), quote 

on p. 239.

135 “The E.J. Baldes I Knew.” 

136 Ibid.

137 Ibid.

138 Biography of Maj. Gen. Otis Otto Benson, Jr., located at 

http://www.af.mil/information/bios/bio.asp?bioID=4669.

139 “The E.J. Baldes I Knew.” 

140 “Clark News,” located at http://www.clarku.edu/alumni/clarknews/

summer05/memoriam.cfm.

141 Min Chueh Chang, “Recollections of 40 years at the Worcester 

Foundation for Experimental Biology,” Physiologist, October 1985, 

Vol. 5. 

142 “The E.J. Baldes I Knew;” Combat Flying Equipment: U.S. Army 

Aviator’s Personal Equipment, 1917–1945.

143 “The E.J. Baldes I Knew.” 

144 “The War Against Gravity.” 

145 Since 1996, the Munsingwear label and logo have been owned by 

PerryEllis International, an international clothing manufacturer.

146 “The E.J. Baldes I Knew.” an essay in the informal autobiography 

of David Clark, (Worcester, MA: David Clark Company, 1992). 

147 “Worcester’s Industrial Heritage: Heald Machine Company,” 

located at http://www.worcesterhistory.org/enterprise-3b-heald.html; 

“The E.J. Baldes I Knew.” 

148 Ibid.

149 “The E.J. Baldes I Knew.” 

150 Ibid.

151 “The E.J. Baldes I Knew;” Earl H. Wood, “Evolution of Anti-g 

Suits, Their Limitations, and Alternative Methods for Avoidance 

of G-Induced Loss of Consciousness,” Final Report, DARPA contract N66001-87-C-0079, May 1990; “The War Against Gravity.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

432

Endnotes: Chapter 3

152 “The E.J. Baldes I Knew.” 

153 “The War Against Gravity;” “An Explanation of Pilot Blackout 

and the Evolution of Preventive Equipment: Clothes Make 

the Superman.” 

154 Ibid.

155 “The E.J. Baldes I Knew.” 

156 E.H. Wood, E.H. Lambert, C.F. Code, and E.J. Baldes, “Factors 

Involved in the Protection Afforded by Pneumatic Anti-Blackout 

Suits, “ National Research Council, Division of Medical Sciences, 

Report No. 351, August 24, 1944.

157 Earl H. Wood and E.H. Lambert, “Factors Influencing the 

Efficacy of Anti-g Equipment at Present in Use,” Report No. 

442 of the National Research Council, Division of Medical 

Sciences, May 24, 1945.

158 “The E.J. Baldes I Knew.” 

159 Ibid.

160 “Worcester’s Industrial Heritage: Heald Machine Company,” 

located at http://www.worcesterhistory.org/enterprise-3b-heald.

html; “The E.J. Baldes I Knew;” http://www.imi-cornelius.com/ 

es/index.html

161 The G-Whiz name is reported in, Obituary, “Charles Code, 87, 

Leader in Allergy Research, New York Times, December 12, 1997.

162 “The E.J. Baldes I Knew.” 

163 “The E.J. Baldes I Knew;” David M. Clark, “The Harry Schroeder 

I Knew,” an essay in the informal autobiography of David Clark 

(Worcester, MA: David Clark Company, 1992).

164 “The E.J. Baldes I Knew.” 

165 Earl H. Wood and E.H. Lambert, “Factors Influencing the Efficacy of Anti-g Equipment at Present in Use,” Report No. 442 of 

the National Research Council, Division of Medical Sciences, 

May 24, 1945; “The Harry Schroeder I Knew.” 

166 L.P. Harrington, Harold Lamport, and E.C. Hoff, “Pneumatic 

anti-acceleration suits: A new design applying the principle of 

the pneumatic lever,” Committee on Medical Research Report, 

April 5, 1943; J.P. Henry, D.R. Drury, P.O. Greeley, and V.R. 

Bennett, “A study of the physiological requirements of an emergency pressure suit permitting survival at 60,000 feet,” part of 

Project MX-829, Aeromedical Laboratories, USC, May 5, 1946, 

as attached to USAAF/AMC Engineering Division Memorandum 

Report TSEAA-660-100, May 5, 1946; “The E.J. Baldes I Knew.” 

167 “Pneumatic anti-acceleration suits: A new design applying the principle of the pneumatic lever;” “The E.J. Baldes I Knew.” 

168 George A. Hallenbeck, “Design and Use of Anti-G Suits and 

Their Activating Valves in World War II,” AAF Technical Report 

No. 5433, March 6, 1946; “The E.J. Baldes I Knew.” 

169 “The E.J. Baldes I Knew.” 

170 “The War Against Gravity.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

433

Endnotes: Chapter 3

171 “An Explanation of Pilot Blackout and the Evolution of 

Preventive Equipment: Clothes Make the Superman;” “The 

E.J. Baldes I Knew.” 

172 Dr. Edward H. Lambert, M.D., “The Clark Nylon Bladder 

Suit,” a paper presented at the meeting of the Subcommittee 

on Acceleration, June 7, 1944.

173 P.F. Scholander, “Final Report on Anti-G Flying Suits: Comparative Tests of Clark and Berger Models,” AAF Proving Ground 

Command Report No. 3-44-77, September 1, 1944.

174 In early 1941, the Experimental Engineering Section of the US 

Army Air Corps Materiel Division began assigning MX designators (for Materiel, Experimental) to many of its development projects. These numbers provided a non-descript means of identifying 

new R&D programs in engineering orders, correspondence, and 

procurement contracts. The practice continued until 1952 when 

the Weapon System designation came into vogue. For further 

details, see Andreas Parsch, “Designations of U.S. Air Force Projects,” located at http://www.designation-systems.net/usmilav/projects.

html#_MX.

175 “Conference on Anti-G Equipment,” Aero Medical Laboratory 

Memorandum Report No. TSEAL3-696-51-I, March 3, 1944.

176 “Conference on Anti-G Equipment;” George A. Hallenbeck, 

“Design and Use of Anti-G Suits and Their Activating Valves in 

World War II,” AAF Technical Report No. 5433, March 6, 1946.

177 “The War Against Gravity.” 

178 “Use, Maintenance and Storage of Fighter Pilot’s Pneumatic 

Suit (Anti-G) Types G-3 and G-3A,” USAAF T.O.-13-1-23, 

July 1, 1949.

179 “The Harry Schroeder I Knew;” conversation with Jack Bassick 

at David Clark Company, March 16, 2009.

180 “The E.J. Baldes I Knew.” 

181 Ibid.

182 “An Explanation of Pilot Blackout and the Evolution of Preventive 

Equipment: Clothes Make the Superman;” conversations with 

Joe Ruseckas at David Clark Company, February 2010.

183 Earl H. Wood and E.H. Lambert, “Factors Influencing the Efficacy of anti-g equipment at Present in Use,” Report No. 442 of 

the National research Council, Division of Medical Sciences, 

May 24, 1945.

184 “Evolution of Anti-g Suits, Their Limitations, and Alternative 

Methods for Avoidance of G-Induced Loss of Consciousness.” 

185 “The E.J. Baldes I Knew.” 

186 “The E.J. Baldes I Knew.” MDAP, or the Mutual Defense Assistance Program, was the result of the Mutual Defense Assistance 

Act passed by Congress and signed into law by President Harry 

S. Truman on 8 October 1949. It provided military assistance to 

allies in danger of attack by the Soviet Union. Between 1950 and 

1967, $33.4 billion in arms and services and $3.3 billion worth of 

surplus weaponry were provided under the program.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

434

Endnotes: Chapter 3

187 Roy W. Thompson, et. al., “Engineering Test and Evaluation 

During High-G,” USAF School of Aerospace Medicine Report 

SAM-TR-78-12, June 1978.

188 Ibid.

189 Ibid.

190 Air Crew Survival Equipmentman 2, NAVEDTRA 80830 

(Washington, DC: U.S. Navy, 1996).

191 Jules Z. Lewyckyi, “USN/USAF Anti-G Suit Consolidation 

Program,” NavAir Report NADC-83076-60, August 22, 1983.

192 “USN/USAF Anti-G Suit Consolidation Program;” “Suit, Anti-G, 

CSU-13B/P,” located at http://www.lifesupportintl.com/products/

Suit_Anti_G_CSU_13B_P-641-357.html.

193 Capt. George B. Kemper and Maj. Alain B. Lacharite, “Limited 

Evaluation of the Tactical Flight Combat Suit in the F-16,” 

AFFTC-TR-89-38, December 1989.

194 Ibid.

195 “Evolution of Anti-g Suits, Their Limitations, and Alternative 

Methods for Avoidance of G-Induced Loss of Consciousness.” 

196 Kalikiano Kalei, “Tactical Life Support System: Precursor to 

Combat Edge.”

197 Ibid.

198 George D. Hedges, “Combat Edge Design Considerations,” 

Gentex Corporation White Paper, January 15, 2004.

199 Jeff Rhodes, “The Well-Dressed Raptor Pilot,” Code One 

Magazine, Vol. 19, No. 4, 2004.

200 “Combat Edge Design Considerations.” 

201 Maj. Mark Mavity, USAF (MC), SFS Resident, USAF School 

of Aerospace Medicine.

202 “Combat Edge Design Considerations;” Comments by George 

D. Hedges from Gentex while reviewing a draft version of 

this manuscript.

203 “Combat Edge Design Considerations.” 

204 Comments by George D. Hedges from Gentex while reviewing 

a draft version of this manuscript.

205 “Navy Training System Plan for Aviation Life Support Systems,” 

NavAir document N88-NTSP-A-50-9206A/D, June 2000.

206 Ibid.

207 Comment by George D. Hedges from Gentex while reviewing 

a draft version of this manuscript.

208 Details of the Atlantis Warrior effort provided by Dr. Jan Stepanek 

at the Mayo Clinic in an email on June 24, 2010.

209 Paolo Gianvanni, “Pilot Life Support Systems,” located at 

http://www.redorbit.com/news/science/330803/pilot_life_support_ 

systems/index.html.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

435

Endnotes: Chapter 3

210 Comments from Dr. Jan Stepanek at Mayo Clinic; H. Welsch, 

W. Albery, and W. Bles, “Physiological Consequences: 

Cardiopulmonary, Vestibular, And Sensory Aspects,” presented at 

SAFE. Reno, Nevada, October 9-11, 2000.

211 Details of the Libelle development effort provided by Dr. Jan 

Stepanek at the Mayo Clinic in an email on 24 June 2010.

212 P. Demitry, P., “U.S. Air Force Evaluation of the Libelle Water 

Augmented Anti-G Suit,” presented at SAFE. Reno, Nevada, 

October 9-11, 2000.

213 Details of the Libelle development effort provided by Dr. Jan 

Stepanek at the Mayo Clinic in an email on June 24, 2010.

214 “Tactical Life Support System: Precursor to Combat Edge.”

215 “Combat Edge Design Considerations.” 

216 Jeff Rhodes, “The Well-Dressed Raptor Pilot,” Code One 

Magazine, Vol. 19, No. 4, 2004.

217 Contract FA8902-08-C-1008, June 30, 2008, located at https://

www.fbo.gov/?s=opportunity&mode=form&tab=core&id= 

3c481dcb24e585526c3d409ee1b27efc&_cview=0.

218 “Advanced Technology Anti-G Suit (ATAGS) Drawing List,” 

HSG/TAAM document, Brooks City-Base, TX, March 20, 2006.

219 Ulf Balldin, Robert O’Conner, Wayne Isdahl, and Paul Werchan, 

“Modification and Test of the CSU-13B/P G-Suit for Use in 

the F/A-22,” Air Force Research laboratory Report AFRL-HEBR-TR-2005-0046, June 2005.

220 Ibid.

221 Dr. John W. Burns and Lt. Col. Ronald C. Hill, “Comparative 

Centrifuge Evaluation of the Air Force Advanced Technology 

Anti-G Suit (ATAGS) and the Nay Enhanced Anti-G Lower 

Ensemble (EAGLE),” Crew Technology Division paper 

AL/CF-PC-1993-0052, December 30, 1993.

222 Ibid.

223 Lloyd D. Tripp, Jr., “Evaluation of the Retrograde Inflation AntiG Suit (RIAGS),” Air Force Materiel Command Report AL-TR1992-0176, December 1992.

224 Ibid.

225 “Flyers Coverall with Integrated Progressive Pressure Anti-G Suit, 

Optional Use Arterial Occlusion Cuffs, and Capstan Sleeves,” 

David Clark Company document 40045G-01, March 14, 1989.

226 “Evaluation of the Retrograde Inflation Anti-G Suit (RIAGS).”
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

436

Endnotes: Chapter 4

CHAPTER 4

1

 Harold J. Jacobs, Kenneth E. Penrod, and David M. Clark, 

“Considerations for Improvements in Altitude Suits,” AF Technical 

Report 6026, July 1950.

2

 Ibid.

3

 Christopher T. Carey, “A Brief History of US Military Aviation 

Oxygen Breathing Systems,” located at http://webs.lanset.com/aerolusaero/Articles/A_Brief_History_of_US_Military_Aviation_Oxygen_Breathing_Systems.pdf.

4

 Helen W. Schultz, “Informal Interview with Dr. James P. Henry, 

Medical Research Consultant and Chief, Acceleration Unit, Aero 

Medical Library,” September 8, 1950.

5

 Obituary, “A.P. Gagge, 85, A Biophysicist and Researcher,” The 

New York Times, February 19, 1993; For further information on 

the John B. Pierce Laboratory, see: http://www.jbpierce.org/.

6

 Helen W. Schultz, “Informal Interview with Colonel A.P. Gagge, 

USAF (MC), Chief, Medical Research Division, Office of the 

Surgeon General, Headquarters, USAF,” February 1, 1951.

7

 Charles L. Wilson, Physiological Protection of the CSU-4/P High 

Altitude Pressure Suit, (Wright-Patterson AFB: Aerospace 

Medical Research Laboratory, 1962); “Informal Interview with 

Colonel A.P. Gagge.”

8

 “Informal Interview with Colonel A.P. Gagge.”

9

 David M. Clark, “The E.J. Baldes I Knew,” an essay in the 

informal autobiography of David Clark (Worcester, MA: David 

Clark Company, 1992); David M. Clark, “The Development of 

the Partial-pressure Suit (PPS) and Something of Its Value,” an 

essay in the informal autobiography of David Clark (Worcester, 

MA: David Clark Company, 1992); “Informal Interview with Dr. 

James P. Henry.”

10 “Informal Interview with Colonel A.P. Gagge;” W.M. Boothby, 

“Summary of the development of positive pressure closed-circuit 

jacket to be used in attempting to attain attitudes as high as 

50,000 feet,” National Research Council, Medical Research 

Division Report No. 3, April 20, 1943.

11 J.P. Henry, D.R. Drury, P.O. Greeley, and V.R. Bennett, “A study 

of the physiological requirements of an emergency pressure suit 

permitting survival at 60,000 feet,” part of Project MX-829, 

Aeromedical Laboratories, USC, May 5, 1946, as attached to 

USAAF/AMC Engineering Division Memorandum Report 

TSEAA-660-100, May 5, 1946.

12 “Informal Interview with Colonel A.P. Gagge.”

13 Helen W. Schulz, “Case History of Pressure Suits,” Air Materiel 

Command, May 1951.

14 “Informal Interview with Colonel A.P. Gagge.”

15 “Case History of Pressure Suits.” 

16 “Informal Interview with Dr. James P. Henry.”
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

437

Endnotes: Chapter 4

17 Ibid.

18 The PR.XI was a reconnaissance version of the Spitfire Mk IX. 

The 14th Photographic Reconnaissance Squadron of the Eighth 

Air Force operated PR.XIs from November 1943 to April 1945, 

flying long-range reconnaissance missions over Europe. One of 

these aircraft is on display at the National Museum of the United 

States Air Force.

19 “A Brief History of US Military Aviation Oxygen Breathing 

Systems.” 

20 The USC contract was OEMomr-288. There were a variety of 

“aero medical” units and laboratories between the military services, 

USC, Mayo Clinic, and others. The documentation of the era 

is very inconsistent if “aero medical” was one word or two, if it 

was hyphenated, and even if it was capitalized for each of the 

entities. I have tried to be consistent here with the USAAF 

Aero Medical Laboratory, the Mayo Aero Medical Unit, and 

the USC Aeromedical Laboratory.

21 Charles C. Lutz and John W. Heim, “Standardization of Altitude 

Suits, Types T-1 and S-1,” USAF Technical Memorandum 

Report WCRD-52-121, SEO-660-141, 20 November 1952; 

“Office of Scientific Research and Development,” located at 

http://history.sandiego.edu/gen/WW2Timeline/OSRD.html; “Executive Order 8807 Establishing the Office of Scientific Research and 

Development,” located at http://www.presidency.ucsb.edu/ws/index.

php?pid=16137

22 Biography of James P. Henry at the International Space Hall of 

Fame, located at http://www.nmspacemuseum.org/halloffame/detail.

php?id=95

23 David M. Clark, “The E.J. Baldes I Knew,” an essay in the informal autobiography of David Clark (Worcester, MA: David Clark 

Company, 1992).

24 David M. Clark, “The Development of the Partial-pressure Suit 

(PPS) and Something of Its Value,” an essay in the informal autobiography of David Clark (Worcester, MA: David Clark Company, 

1992).

25 Helen W. Schultz, “Informal Interview with Dr. James P. Henry, 

Medical Research Consultant and Chief, Acceleration Unit, Aero 

Medical Library,” September 8, 1950.

26 “The E.J. Baldes I Knew.” 

27 “Standardization of Altitude Suits, Types T-1 and S-1.” 

28 “Case History of Pressure Suits.” 

29 “Informal Interview with Dr. James P. Henry; “Case History of 

Pressure Suits.” 

30 J.P. Henry, P. O. Greeley, J. Meehan, and D.R. Drury, A Case 

of Sudden Swelling of the Hands Occurring at 58,000 Feet Simulated Altitude, Committee on Aviation Medicine Report No. 393 

(Washington, DC: National Research Council, December 1, 

1944).

31 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet.” 

32 The portion of the body in the pelvis occupied by urogenital passages and the rectum, bounded in front by the pubic arch, in the 

back by the coccyx, and laterally by part of the hipbone.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

438

Endnotes: Chapter 4

33 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet.” 

34 A Case of Sudden Swelling of the Hands Occurring at 58,000 Feet 

Simulated Altitude.

35 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet;” A Case 

of Sudden Swelling of the Hands Occurring at 58,000 Feet 

Simulated Altitude.

36 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet.” 

37 “Informal Interview with Dr. James P. Henry;” “A Study of the 

Physiological Requirements of an Emergency Pressure Suit 

Permitting Survival at 60,000 Feet.” 

38 Corrections to the Henry Suit description supplied by Jack Bassick 

at the David Clark Company in a letter to Dennis R. Jenkins, 

June 3, 2002.

39 “Standardization of Altitude Suits, Types T-1 and S-1.” 

40 James Henry and Joshua D. Chatham, “Altitude Tests of the 

Partial-Pressure Suit,” part of Project MX-829, USAAF/AMC 

Engineering Division Memorandum Report TSEAA-660-100-A, 

June 20, 1946. 

41 Ibid. 

42 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet.” 

43 “Altitude Tests of the Partial-Pressure Suit.” 

44 Ibid. 

45 “A Study of the Physiological Requirements of an Emergency 

Pressure Suit Permitting Survival at 60,000 Feet.” 

46 Ibid.

47 “Altitude Tests of the Partial-Pressure Suit.” Pinecastle AAF later 

became McCoy AFB and is the current site of the Orlando 

International Airport.

48 “Case History of Pressure Suits.” 

49 “Case History of Pressure Suits;” Contract W33-038-ac-15165, 

purchase order 46-3140-E, February 28, 1946.

50 “The Development of the Partial-pressure Suit (PPS) and 

Something of Its Value;” “Initial Glide Flights,” located at 

http://www.cebudanderson.com/initialglideflights.htm.

51 Harold J. Jacobs, Kenneth E. Penrod, and David M. Clark, 

“Considerations for Improvements in Altitude Suits,” 

AF Technical Report 6026, July 1950.

52 “Standardization of Altitude Suits, Types T-1 and S-1.” 

53 “The Development of the Partial-pressure Suit (PPS) and 

Something of Its Value.” 

54 “Considerations for Improvements in Altitude Suits;” “Case 

History of Pressure Suits.” 

55 “The Development of the Partial-pressure Suit (PPS) and 

Something of Its Value;” conversation with Jack Bassick 

and Joe Ruseckas, March 19, 2009.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

439

Endnotes: Chapter 4

56 “Case History of Pressure Suits.” This was actually Change No. 2 

to contract W33-038-ac-15165. 

57 “Case History of Pressure Suits.” 

58 Correspondence between Dennis R. Jenkins and James Young, 

AFFTC Historian, Edwards AFB, California, January 2010, and 

conversation between Jim Young and Chuck Yeager, January 2010.

59 James P. Henry, Patent 2,886,027, “Partial-pressure Suit,” 

May 12, 1959.

60 “Case History of Pressure Suits.” This was actually Change No. 3 

to contract W33-038-ac-15165. 

61 Charles A. Dempsey, Air Force Aerospace Medical Research 

Laboratory: 50 Years of Research on Man in Flight (Wright-Patterson 

AFB, OH: U.S. Air Force, 1985).

62 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009.

63 Biography provided by Jack Bassick at David Clark Company 

and also from several dinners with Joe Ruseckas; Email from 

Jack Bassick reporting Joe had passed away earlier that day, 

March 19, 2010.

64 “Case History of Pressure Suits.” 

65 Ibid.

66 Jay Miller, The X-Planes: X-1 to X-45 (Hinckley, UK: Midland 

Counties Publishing, 2001).

67 A. Scott Crossfield, Always Another Dawn: The Story of a Rocket 

Test Pilot (Cleveland, OH: World Publishing Co., 1960); The 

X-Planes: X-1 to X-45.

68 “Standardization of Altitude Suits, Types T-1 and S-1;” “Case 

History of Pressure Suits.” 

69 “Standardization of Altitude Suits, Types T-1 and S-1.” 

70 The 5.3-pound weight was impressive given the G-4A g-suit 

weighed 3.3 pounds and the S-2 pressure suit weighed 3.4 pounds.

71 “Case History of Pressure Suits.” 

72 Letter, David M. Clark, David Clark Company, to Aero Medical Laboratory, January 12, 1950, subject: standard sizes; Letter, 

Col. Walter A. Carlson, Chief, Aero Medical Laboratory, to David 

Clark Company, February 1, 1950; “History of the Wright Air 

Development Center, 1 July–31 December 1955, Volume IV.”

73 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

74 Letter, North American Aviation, Inc. to Chief, Aero Medical 

Laboratory, December 16, 1949, subject: Pressure Suit Availability.

75 Letter, Col. Walter A. Carlson, Chief, Aero Medical Laboratory, 

to North American Aviation, January 5, 1950.

76 Letter, David M. Clark to Aero Medical Laboratory, December 22, 

1949, subject: Partial-pressure Suit Bid.

77 “Case History of Pressure Suits.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

440

Endnotes: Chapter 4

78 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

79 Ibid.

80 Bruce W. Pinc, “MC-3, MC-4 Altitude Suit Assemblies 

Description, Fitting, and Maintenance,” WADC Technical Report 

56-654, December 1956.

81 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

82 News Release, “Emergency Pressure Suit Developed by Air Force,” 

October 4, 1952.

83 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

84 “Standardization of Altitude Suits, Types T-1 and S-1.” 

85 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

86 Ibid.

87 Ibid.

88 T.O. 1B-36J-1, “Flight Handbook: USAF Series B-36J-III 

Aircraft; Featherweight—Configuration III,” revised April 6, 1956, 

pp. 810-812 “Mission C.”

89 Maximum continuous power was 2,650-bhp for the R-4360s and 

96-percent for the J47s. For more information on the B-36, please 

see Dennis R. Jenkins, Magnesium Overcast (North Branch, MN: 

Specialty Press, 2001) or Don Pyeatt and Dennis R. Jenkins, Cold 

War Peacemaker (North Branch, MN: Specialty Press, 2010).

90 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

91 Ibid.

92 Ibid.

93 Capt. Terence F. McGuire, “Physiological and Operational 

Comparison of the MC-1 and MC-3 (MC-4) Partial-pressure 

Suits,” Biomedical Laboratory, WADC Technical Report 

57-536(I), October 1960.

94 Ibid., quote on p. 7.

95 Ibid.

96 Capt. Charles L. Wilson and Capt. Myron B. Zinn, Aerospace 

Medical Laboratory, “Medical problems in Testing High Altitude 

Pressure Suits,” Aerospace Medicine, January 1960.

97 Ibid.

98 Ibid.

99 “Physiological and Operational Comparison of the MC-1 and 

MC-3 (MC-4) Partial-pressure Suits,” quote on p. 22.

100 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

101 Frederick A. Alling, “History of the Air Materiel Command, 

1 July–31 December 1956, Volume IV: The F-102A Airplane, 

1950-1956.”

102 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

441

Endnotes: Chapter 4

103 Ibid.

104 “The Development of the Partial-pressure Suit (PPS) and 

Something of Its Value.” 

105 Ibid.

106 Dennis R. Jenkins, Lockheed U-2 Dragon Lady, WarbirdTech 

Vol. 16 (North Branch, MN: Specialty Press, 1998).

107 Ibid.

108 Sebastian Junger, “The Escape Artist,” The New York Times, 

January 4, 1998.

109 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversation with Jack Bassick and Joe Ruseckas 

at David Clark Company, February 2010.

110 “Firewel,” located at http://roadrunnersinternationale.com/ 

firewel.html; email with Jack Bassick at David Clark Company, 

February 17, 2010.

111 Ibid.

112 Email from Ken Przybyla to Dennis R. Jenkins, March 1, 2010; 

Carlton history, located at http://www.carltech.com/about_us/ 

history.htm

113 Capt. Terence F. McGuire, “Physiological and Operational 

Comparison of the MC-1 and MC-3 (MC-4) Partial-pressure 

Suits,” Biomedical Laboratory, WADC Technical Report 

57-536(I), October 1960.

114 Ibid; “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

115 Biography of Martin A. Knutson, located at http://www.nasa.gov/

centers/dryden/news/Biographies/Directors/knutson.html

116 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

117 “MC-3, MC-4 Altitude Suit Assemblies Description, Fitting, 

and Maintenance.”

118 David M. Clark, “The Development of the Partial-pressure Suit 

(PPS) and Something of Its Value,” an essay in the informal autobiography of David Clark (Worcester, MA: David Clark Company, 

1992); conversation with Jack Bassick at David Clark 

Company, March 16, 2009. Although not called Link-Net in the 

patent application, the material was part of the intellectual property covered by patent 3,081,459 of March 19, 1963 (filed 

by David M. Clark on January 14, 1958).

119 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

120 Ibid.; Charles C. Lutz, Development of an Emergency Pressure Suit 

(Coveralls, High-Altitude, Type CSU-4/P), WADC Technical Note 

59-148, July 1959.

121 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

122 Charles C. Lutz, “Development of an Emergency Pressure Suit 

(Coveralls, High-Altitude, Type CSU-4/P),” WADC Technical 

Note 59-148, July 1959.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

442

Endnotes: Chapter 4

123 David Clark model number list supplied by Jack Bassick; 

Production numbers provided by Bob Banks and Ed Dubois at 

David Clark Company, May 2010.

124 “MC-3, MC-4 Altitude Suit Assemblies Description, Fitting, 

and Maintenance.”

125 David Clark model number list supplied by Jack Bassick.

126 “MC-3, MC-4 Altitude Suit Assemblies Description, Fitting, 

and Maintenance.”

127 Ibid.

128 Fred D. Moller, “High-Altitude, Partial-Pressure Suits Designed 

with Double Capstans, Ventilation Layers, and Partial-pressure 

and Full-pressure Socks,” WADC Technical Report 59-246, 

June 1959; “Development of an Emergency Pressure Suit 

(Coveralls, High-Altitude, Type CSU-4/P).”

129 “MC-3, MC-4 Altitude Suit Assemblies Description, Fitting, 

and Maintenance.”

130 David Clark model number list supplied by Jack Bassick; conversations with Jack Bassick, Bob Banks, and Ed Dubois at David 

Clark Company, February 2010.

131 Christopher T. Carey, “Supporting Life at 80,000 Feet: Evolution 

of the American High Altitude Pressure Suit.”

132 Gregory P. Kennedy, “Project Manhigh,” located at http://www.

ispyspace.com/Project%20Manhigh.

133 Ibid; Project Manhigh Fact Sheet, located at http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=560.

134 Project Manhigh Fact Sheet; “The Development of the Partialpressure Suit (PPS) and Something of Its Value.” 

135 Joseph A. Ruseckas at David Clark Company, “Notes Taken 

From Letter From David G. Simons, Major, USAF (MC), Dated 

13 November 1957.”

136 Ibid. 

137 Biography of Dr. John P. Stapp. Air Force Flight Test Center Public Affairs Office, Edwards AFB.

138 Project Excelsior Fact Sheet, located at http://www.nationalmuseum.

af.mil/factsheets/factsheet.asp?id=562.

139 Ibid.

140 Biography of Joseph Kittinger,” located at http://en.wikipedia.org/

wiki/Joseph_Kittinger; email with Malcolm Todd, who asked Kittinger about the sonic fall while prepping for the Red Bull Stratos 

jump, January 27, 2010.

141 “Joe Kittinger,” part of the publicity package put together by Red 

Bull Stratos and distributed on January 22, 2010.

142 Project Excelsior Fact Sheet.

143 Biography of Joseph Kittinger;” email with Malcolm Todd, who 

asked Kittinger about the sonic fall while prepping for the Red 

Bull Stratos jump, January 27, 2010.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

443

Endnotes: Chapter 4

144 Biography of Joseph Kittinger.” 

145 “High-Altitude, Partial-Pressure Suits Designed with Double 

Capstans, Ventilation Layers, and Partial-pressure and FullPressure Socks.”

146 Ibid.

147 Ibid.; “Development of an Emergency Pressure Suit (Coveralls, 

High-Altitude, Type CSU-4/P).”

148 David Clark model number list supplied by Jack Bassick.

149 Letter, David Clark Company to Aer-AE-51, Airborne Equipment 

Division, subject: Contract NOas-55-882-f, Suit, High-Altitude, 

Type C-1A, fitting of, April 4, 1956.

150 David Clark model number list supplied by Jack Bassick.

151 Letter, David Clark Company to Aer-AE-51, Airborne Equipment 

Division, subject: Contract NOas-55-882-f, Suit, High-Altitude, 

Type C-1A, fitting of, April 4, 1956.

152 David Clark model number list supplied by Jack Bassick.

153 “C-4 Suit,” located at http://www.astronautix.com/craft/c4.htm; 

David Clark model number list supplied by Jack Bassick.

154 “Development of an Emergency Pressure Suit (Coveralls, HighAltitude, Type CSU-4/P).”

155 Ibid.

156 Charles L. Wilson, “Physiological Protection of the CSU-4/P 

High-Altitude Pressure Suit,” Biomedical laboratory, WADC 

Technical Report AMRL-TDR-61-112, September 1962.

157 Ibid.

158 “Development of an Emergency Pressure Suit (Coveralls, 

High-Altitude, Type CSU-4/P).”

159 Ibid.

160 Joseph A. Ruseckas, “Development of an Emergency Pressure Suit 

Coverall, High Altitude, Ventilation-Exposure, Type CSU-5/P,” 

WADD Technical Report 60-809, November 1960.

161 The New Zipper Company was founded in January 1954 following two years of research and development during which time the 

zipper basic design was perfected, and machinery constructed to 

manufacture the zipper. The company manufactured the world's 

first completely sealing slide fastener. The first use was sealed 

storage for UK military equipment followed by military dry diving suits. It was about this time that the slider first displayed the 

“BDM” mark derived form the names of those closely involved 

in the design. Mr. Bercovitz was an industrialist who employed 

Dr. Doelter to lead a team to develop the mass production of a 

zipper designed by Mr. Mulka. The New Zipper Company is now 

part of the Japanese YKK Group.

162 “Development of an Emergency Pressure Suit Coverall, HighAltitude, Ventilation-Exposure, Type CSU-5/P,”.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

444

Endnotes: Chapter 4

163 Jimmy B. Graves, “Monthly Progress Report for the Altitude 

Protective Garment Program, Period 1 November 1972 to 30 

November 1972,” contract NAS4-1961, document No. 100161-1, 

8 December 1972.

164 Jimmy B. Graves, “Monthly Progress Report for the Altitude 

Protective Garment Program, Period 1 December 1972 to 

30 December 1972,” contract NAS4-1961, document 

No. 100161-2, 8 January 1973.

165 Jimmy B. Graves, “Monthly Progress Report for the Altitude 

Protective Garment Program, Period 1 January 1973 to 31 January 

1973,” contract NAS4-1961, document No. 100161-3, February 9, 

1973; Jimmy B. Graves, “Monthly Progress Report for the Altitude 

Protective Garment Program, Period 1 March 1973 to 31 March 

1973,” contract NAS4-1961, document No. 100161-5, 

April 10, 1973.

166 Jimmy B. Graves, “Final Monthly Progress Report for the 

Altitude Protective Garment Program, Period 1 June 1973 to 

12 June 1973,” contract NAS4-1961, document No. 100161-8, 

June 28, 1973.

167 Jimmy B. Graves, “Monthly Progress Report for the Altitude 

Protective Garment Program, Period 1 March 1973 to 31 March 

1973,” contract NAS4-1961, document No. 100161-5, 

April 10, 1973.

168 Jimmy B. Graves, “Final Monthly Progress Report for the 

Altitude Protective Garment Program, Period 1 June 1973 to 

12 June 1973,” contract NAS4-1961, document No. 100161-8, 

June 28, 1973.

169 Jewel M. Melvin, Physiological Support Division, Edwards AFB, 

“Pressure Suits—How and Why,” SAFE Journal, Vol. 8, 

No. 1, 1978.

170 Wing Commander H.L. Roxburgh, Flight Lieutenant J. Ernsting, 

and Flight Lieutenant I.J. Badger, “The Pressure Jerkin,” Flight 

Personnel Research Committee Report 948, January 1956.

171 Ibid.

172 George R. Ashworth, et. al., “Flight Test Evaluation of an RAF 

High Altitude Partial-Pressure Protective Assembly,” NASA 

Technical Memorandum 72864, June 1979.

173 Ibid.

174 Wing Commander D.P. Gradwell, RAF Center of Aviation 

Medicine, “Royal Air Force High Altitude Physiological Training,” 

a paper presented at the RTO HTM Workshop on Aeromedical 

Aspects of Aircrew Training, San Diego, October 14-18, 1998; 

“Flight Test Evaluation of an RAF High Altitude Partial-Pressure 

Protective Assembly.” 

175 “Flight Test Evaluation of an RAF High Altitude Partial-Pressure 

Protective Assembly.” 

176 Ibid.

177 Ibid.

178 Ibid.

179 Conversations with Jack Bassick and Ed Dubois at David Clark 

Company, February 2010.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

445

Endnotes: Chapter 5

CHAPTER 5

1

 Vernon G. Townsend, Vice President and John D. Akerman, 

Consultant, “Report on U.S. Navy Pressure Suit, Model 7, on 

Contract NOa(s) 8192,” November 15, 1947.

2

 Ibid.

3

 Ibid.

4

 Ibid.

5

 Dr. Earl H. Wood, letter to LCDR Ralph L. Chritsy, June 24, 1947.

6

 “Report on U.S. Navy Pressure Suit, Model 7.”

7

 “Omni-Environment Suit Development Progress Report,” 

submitted under contract NOa(s)-9931, September 30, 1948. 

8

 Ibid. 

9

 Harold J. Jacobs, Kenneth E. Penrod, and David M. Clark, 

“Considerations for Improvements in Altitude Suits,” AF Technical 

Report 6026, July 1950; conversations with Jack Bassick and Joe 

Ruseckas at David Clark Company, February 2010.

10 “Omni-Environment Suit Development Progress Report,” submitted under contract NOa(s)-9931, September 30, 1948. 

11 Ibid. 

12 Helen W. Schulz, “Case History of Pressure Suits,” Air Materiel 

Command, May 1951.

13 “Omni-Environment Suit Development Progress Report No. 2,” 

submitted under contract NOa(s)-9931, July 25, 1949. 

14 Ibid. 

15 “Omni-Environment Suit Development Progress Report No. 3,” 

submitted under contract NOa(s)-9931, March 1950. 

16 Ibid. 

17 “Omni-Environment Suit Development Progress Report No. 4,” 

submitted under contract NOa(s)-9931, October 1950. 

18 Ibid. 

19 Ibid. 

20 Ibid. 

21 “Omni-Environment Suit Development Progress Report No. 5,” 

submitted under contract NOa(s)-9931, January 1951. 

22 Ibid. 

23 The Navy seemingly could not figure out how to designate this 

airplane and it was later called the TV2 and still later, the T-33B. 

In any case, it was a navalized variant of the USAF Lockheed 

T-33 “T-Bird” trainer.

24 “Omni-Environment Suit Development Progress Report No. 5.” 

25 Ibid. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

446

Endnotes: Chapter 5

35 Ibid.

36 “Monthly Progress Report: October 1951,” submitted under 

contract NOa(s)-51-532c, November 1951; “Monthly 

Progress Report: November 1951,” submitted under contract 

NOa(s)-51-532c, December 1951. 

37 “Monthly Progress Report: December 1951,” submitted under 

contract NOa(s)-51-532c, January 1952; “Monthly Progress 

Report: January 1952,” submitted under contract NOa(s)-51-

532c, February 1952 

38 Always Another Dawn, quote on p. 239.

39 Letter from Ira H. Abbott, NACA, to Maj. Gen Frederick R. 

Dent, Jr., August 13, 1951; letter, John W. Crowley to the Chief 

of BuAer, October 23, 1951; Letter, J.E. Sullivan, Director of the 

Airborne Equipment Division, to the NACA, 2 November 1951.

40 Lastex was invented by Dunlop Rubber Company in the 1930s 

by transforming latex into a reliable elastic thread. It is most often 

used with other fibers to create fabrics such as Spandex and foundation garments. Lastex will deteriorate after repeated washing and 

drying, losing its elasticity.

41 “Monthly Progress Report: January 1952,” submitted under contract NOa(s)-51-532c, February 1952. 

42 “Monthly Progress Report: December 1951,” submitted under 

contract NOa(s)-51-532c, January 1952; “Monthly Progress 

Report: January 1952.” 

43 “Monthly Progress Report: December 1951.” 

26 “Omni-Environment Suit Development Progress Report No. 6,” 

submitted under contract NOa(s)-9931, July 1951; “Monthly 

Progress Report: October 1951,” submitted under contract 

NOa(s)-51-532c, November 1951. 

27 LTJG Arnold L. Brown, Herbert R. Greider, and James V. 

Correale, Jr., “Omni-environmental Full-pressure Suit, Research, 

Development, and Test of; Report on AMEL Tests at Douglas 

Aircraft Corporation, El Segundo, California,” Aero Medical 

Equipment Laboratory Report XG-T-176, March 10, 1952.

28 “Monthly Progress Report: October 1951,” submitted under 

contract NOa(s)-51-532c, November 1951. 

29 Ibid; “Omni-environmental Full-pressure Suit, Research, 

Development, and Test of; Report on AMEL Tests.”

30 A. Scott Crossfield, Always Another Dawn: The Story of a Rocket 

Test Pilot (Cleveland, OH: World Publishing Co., 1960), quote on 

p. 239; conversation between the author and Crossfield, May 29, 

2002.

31 “Monthly Progress Report: November 1951,” submitted under 

contract NOa(s)-51-532c, December 1951. 

32 “Omni-Environmental Full-Pressure Suit, Research, Development, 

and Test of; Report on AMEL Tests.”

33 “Monthly Progress Report: December 1951,” submitted under 

contract NOa(s)-51-532c, January 1952. 

34 “Omni-Environmental Full-Pressure Suit, Research, Development, 

and Test of; Report on AMEL Tests.”
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Endnotes: Chapter 5

53 Letter, Director of the Naval Air Experimental Station to the 

Chief, Bureau of Aeronautics, March 10, 1954.

54 Letter, Director, Naval Air Experimental Station to Chief, Bureau 

of Aeronautics, March 10, 1954.

55 “Progress Report: April 1952 through January 1953,” submitted 

under contract NOa(s)-51-532c, April 1953. 

56 Ibid. 

57 Letter, Commander, Naval Air Test Center, to Chief, Bureau of 

Aeronautics. March 12, 1954.

58 Ibid.

59 “Progress Report: April 1952 through January 1953.” 

60 Biography of Russell Colley, located at http://www. 

ohiohistorycentral.org/entry.php?rec=2633

61 CAPT Charles F. Gell, Edward L. Hays, and James V. Correale, 

“Developmental History of the Aviator’s Full-Pressure Suit in 

the U.S. Navy,” Journal of Aviation Medicine, Vol. 30, No. 4, 

April 1959.

62 Lillian D. Kozloski, U.S. Space Gear: Outfitting the Astronaut

(Washington DC: Smithsonian Institution Press, 1994). 

63 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

64 Ibid.

44 “Monthly Progress Report: November 1951,” submitted under 

contract NOa(s)-51-532c, December 1951; Jay Miller, X-Planes: 

X-1 to X-45, (Hinkley, UK: Midland Counties Publishing, 2001); 

conversations with Jack Bassick and Joe Ruseckas, David Clark 

Company, March 18, 2009, and February 6, 2010.

45 Letter, F. A. Santner, for the Director of the Naval Air Experimental Station, to the Chief of Bureau of Aeronautics, December 8, 

1953; letter, Lt. Col. Marion E. Carl, to Chief, Bureau of 

Aeronautics, October 28, 1953.

46 Letter, Lt. Col. Marion E. Carl, to Chief, Bureau of Aeronautics, 

October 28, 1953. On Carl’s third flight, this sequence was 

changed to 4, 3, 1, and 2 because the No. 3 chamber would 

initially not light.

47 Ibid. 

48 Ibid. Carl’s comments were relayed, verbatim, to David 

Clark Company in a letter from the Chief of BuAer on 

December 2, 1953.

49 Ibid. 

50 “Monthly Progress Report: January 1952,” submitted under 

contract NOa(s)-51-532c, February 1952. 

51 “Monthly Progress Report: February and March 1952,” submitted 

under contract NOa(s)-51-532c, April 1952. 

52 “Progress Report: April 1952 through January 1953,” submitted 

under contract NOa(s)-51-532c, April 1953. 

447
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

448

Endnotes: Chapter 5

65 “Developmental History of the Aviator’s Full-Pressure Suit in the 

U.S. Navy.” 

66 Ibid.

67 “Navy’s Space Suit,” Naval Aviation News, NavAer No. 00-75R-3, 

April 1953.

68 “Developmental History of the Aviator’s Full-Pressure Suit in the 

U.S. Navy.” 

69 James V. Correale, et. al., “The Lightweight Full-Pressure Suit 

System of the U.S. Navy,” Air Crew Equipment Branch, Naval 

Air Material Center Philadelphia, 1959.

70 “Developmental History of the Aviator’s Full-Pressure Suit in the 

U.S. Navy.” 

71 Ibid.

72 Ibid.

73 Ibid.

74 In a seat kit, the pilot sits on the controller unit, parachute, and 

survival kit whereas in a back kit they are located (naturally 

enough) on his back. This necessitates different seat configurations, 

which can have a major impact on the design of the ejection seat 

and supporting equipment.

75 “Developmental History of the Aviator’s Full-Pressure Suit in the 

U.S. Navy.” 

76 “Developmental History of the Aviator’s Full-Pressure Suit in 

the U.S. Navy.” 

77 “Navy’s Space Suit” Naval Aviation News, NavAer No. 00-75R-3, 

April 1953; “Developmental History of the Aviator’s Full-Pressure 

Suit in the U.S. Navy.” 

78 “Well Garbed for the Stratosphere,” Naval Aviation News, 

NavAer No. 00-75R-3, June 1955.

79 James V. Correale, “Study to Assess the Effectiveness and 

Utilization of Full-Pressure Suits,” Air Crew Equipment 

Laboratory Report NAM-QE-5177, Part 2, April 7, 1960; 

conversations with Jack Bassick and Joe Ruseckas at David 

Clark Company, February 2010.

80 U.S. Space Gear: Outfitting the Astronaut. 

81 “Study to Assess the Effectiveness and Utilization of Full-Pressure 

Suits.” 

82 Ibid.

83 Jeffery L. Rodengen, The Legend of Federal-Mogul (Fort Lauderdale, 

FL: Write Stuff Enterprises, 1997).

84 “Developmental History of the Aviator’s Full-Pressure Suit in 

the U.S. Navy.” 

85 Ibid.

86 “From Post to Present,” Naval Aviation News, NavAer 

No. 00-75R-3, August 1958.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

449

Endnotes: Chapter 5

87 Ibid.

88 “Study to Assess the Effectiveness and Utilization of Full-Pressure 

Suits;” “From Post to Present.” 

89 Conversations with pressure suit historian Dennis Gilliam, 

May 26, 2011.

90 “From Post to Present.” 

91 Ibid.

92 Ibid.

93 CDR Arthur L. Hall and CDR Richard J. Martin, “Prolonged 

Exposure in the Navy Full-pressure Suit at “Space Equivalent” 

Altitudes,” BuAer Report TED-NOR-AE-5100, April 1, 1959; 

Arthur L. Hall and Richard J. Martin, “Prolonged Exposure in the 

Navy Full-Pressure Suit at Space Equivalent Altitudes,” Aerospace 

Medicine, February 1960.

94 “From Post to Present.” 

95 LTJG R. C. Haavind, “Navy has Space Suit Ready,” Naval Aviation News, NavAer No. 00-75R-3, February 1958.

96 William Paul Shanahan and William S. Barker, “Pressure Suit 

Pre-Flight System,” Contract Nonr-3107(00), Matrix Corporation 

Report 62-3, September 1962; “From Post to Present.” 

97 William Paul Shanahan and William S. Barker, “Pressure Suit 

Pre-Flight System,” Contract Nonr-3107(00), Matrix Corporation 

Report 62-3, September 1962; “From Post to Present.” 

98 Marie Pfeiffer, “Navy Pilots Play It Cool,” Naval Aviation News, 

NavAer No. 00-75R-3, March 1960.

99 Ibid.

100 “Mobile Ready Rooms Delivered,” Naval Aviation News, NavAer 

No. 00-75R-3, May 1961.

101 “Ranger Men Try Their New Suits,” Naval Aviation News, NavAer 

No. 00-75R-3, May 1959.

102 The Legend of Federal-Mogul; The Internet Movie Database 

(IMDb), “Westinghouse Desilu Playhouse,” located at 

http://uk.imdb.com/title/tt0745776.

103 U.S. Space Gear: Outfitting the Astronaut. 

104 R. E. Gadolin, Aviation Medicine Research: A Historical Review, 

NAMRL Special Report 92-3 (NAS Pensacola, FL: Naval 

Aerospace Medical Research Laboratory, 1992).

105 “Fitting, Donning, Operation and Maintenance Instructions: 

Light Weight Full-pressure Suit, Mark IV,” Goodrich manual 

GPS-59-1, 1959; “The Lightweight Full-Pressure Suit System 

of the U.S. Navy.” 

106 “The Lightweight Full-Pressure Suit System of the U.S. Navy.” 

107 Ibid.

108 “Fitting, Donning, Operation and Maintenance Instructions: 

Light Weight Full-Pressure Suit, Mark IV.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

450

Endnotes: Chapter 5

109 “The Lightweight Full-Pressure Suit System of the U.S. Navy.” 

110 “Navy Pilots Play It Cool.” 

111 “The Lightweight Full-Pressure Suit System of the U.S. Navy.” 

112 “Navy Pilots Play It Cool.” 

113 “The Lightweight Full-Pressure Suit System of the U.S. Navy;” 

“Navy Pilots Play It Cool.” 

114 “Navy Pilots Play It Cool.” 

115 J.H. Hill, M.G. Webb, and J.L. Brown, “Pilot’s Ability to 

Actuate Ejection Controls: Final Report Concerning,” Bureau 

of Aeronautics Report TED-ADC-AE-5205, February 5, 1959.

116 Ibid.

117 Malcolm Ross and Walter Edwards, “Balloon Ride to the Edge 

of Space,” National Geographic Magazine, November 1961.

118 P. R. Frecka, Goodrich Suit Technician, “Trip Report of Project 

Strato-Lab High #5 From 25 April 1961 to 6 May 1961;” 

“Balloon Ride to the Edge of Space.” 

119 Ibid. Emphasis in original.

120 Ibid; John F. Kennedy, “Remarks on Presenting the Harmon 

Trophies Thursday, October 18, 1962,” the American 

Presidency Project.

121 U.S. Space Gear: Outfitting the Astronaut. 

122 See, for instance, LT Gary L. Kellett, MC, USN, et. al. “FullPressure Suits and Personal Hygiene,” in A Report of the 

Physiological, Psychological, and Bacteriological Aspects of 20 Days in 

Full-Pressure Suits, prepared by the Naval Air Engineering Center, 

NASA CR-708 (Washington DC: NASA, February 1967.

123 Loyd S. Swenson, Jr., James M. Grimwood, and Charles C. 

Alexander, This New Ocean: A History of Project Mercury, 

SP-4201 (Washington DC: NASA, 1966).

124 Ibid.

125 Edwin G. Vail and Charles C. Lutz, “Project Mercury Pressure 

Suit Evaluation,” Report 59-WCLD-898, July 1959.

126 Ibid.

127 Ibid; William Ayrey, ILC Space Suits & Related Products, ILC 

document number 0000-712731, Rev. A, November 28, 2007.

128 “Project Mercury Pressure Suit Evaluation.” 

129 This New Ocean: A History of Project Mercury.

130 “The Lightweight Full-Pressure Suit System of the U.S. Navy.” 

131 “Navy Pilots Play It Cool.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

451

Endnotes: Chapter 6

CHAPTER 6

1

 Helen W. Schulz, “Case History of Pressure Suits,” Air Materiel 

Command, May 1951.

2

 “Altitude Trends for Operational USAF Aircraft,” Technical Note 

WCR-54-1, December 20, 1955.

3

 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

4

 Ibid.

5

 Ibid.

6

 Capt. Norman R. Smedes, 4750th Test Squadron, Tyndall AFB, 

Florida, “Comparative Test of Aircrew Pressure Suits,” Project 

ADC/73AD/60-11, April 1, 1961. Parts of this Report were summarized in an article, “The Final Choice,” ADC Interceptor, Air 

Defense Command, Vol. 5, No. 3, February 1963; email from 

Jewel M. Melvin, Air Force Materiel Command, 576 ACSS, 

Robins AFB, February 17, 2010.

7

 “Comparative Test of Aircrew Pressure Suits.” 

8

 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

9

 Ibid.

10 Papers presented, “Omni-Environment Full-Pressure Suit 

Symposium,” The Franklin Institute, 1-3 February 1955; “History 

of the Wright Air Development Center, 1 July–31 December 

1955, Volume IV.”

11 Arthur S. Iberall, RAND Development Corporation, “The Use of 

Lines of Nonextension to Improve Mobility in Full-Pressure Suits,” 

USAF Behavioral Sciences Laboratory Report AMRL-TR-64-118, 

November 1964.

12 For more on Iberall’s work, see, for instance: A.S. Iberall, 

“Fundamental Considerations in the Design of Mobile Pressure 

Suits,” National Bureau of Standards Report to the Safety 

Equipment Branch, Airborne Equipment Division, Bureau of 

Aeronautics, April 12, 1951, and A.S. Iberall, “Development 

of a Full-Pressure Altitude Suit,” WADC Technical Report 

WADC-58-236, June 1958.

13 A “The Use of Lines of Nonextension to Improve Mobility in 

Full-Pressure Suits.” 

14 Conversations with Jack Bassick and Joe Ruseckas at David Clark 

Company, February 2010.

15 “The Use of Lines of Nonextension to Improve Mobility in FullPressure Suits.” 

16 Ibid.

17 Ibid.

18 Ibid.

19 Ibid.

20 Edwin G. Vail and Richard G. Willis, “Pilot Protection for 

the X-15 Airplane,” a paper in the 1958 Research Airplane 

Committee Report.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

452

Endnotes: Chapter 6

21 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

22 Ibid.

23 Ibid.

24 For the complete story of the X-15, see Dennis R. Jenkins, X-15: 

Extending the Frontiers of Flight, SP-2007-562 (Washington, 

DC: NASA, 2007) and Dennis R. Jenkins and Tony R. Landis, 

Hypersonic: The Story of the North American X-15 (North Branch, 

MN: Specialty Press, 2003).

25 North American Aviation detail specification NA5-4047, April 

8, 1956; memorandum, Lt. Col. K. F. Troup, Chief, Air Crew 

Effectiveness Branch, Aero Medical Laboratory, to Chief, New 

Development WSPO, Fighter Aircraft Division, ARDC, no 

subject, May 4, 1956; telephone conversation, Scott Crossfield 

with Dennis R. Jenkins, June 5, 2000.

26 X-15 WSPO Weekly Activity Report, June 28, 1956. 

27 AMC Form 52 (Record of Verbal Coordination), July 12, 

1956, subject: Personal Equipment for X-15 Weapons System; 

telephone conversation, Scott Crossfield with Dennis R. Jenkins, 

June 5, 2002; letter, S. C. Hellman, Manager, Contracts and 

Proposals, North American Aviation, to Commander, AMC, 

subject: Contract AF33(600)-31693 (X-15) NA-240 Contractual 

Document—Request for Full-Pressure Pilot’s Suit—Change from 

CFE to GFAE, ECP NA-X-15-8, February 8, 1957. 

28 “History of the Wright Air Development Center, 1 July– 

31 December 1955, Volume IV.”

29 Edwin G. Vail and Richard G. Willis, “Pilot Protection for 

the X-15 Airplane,” a paper in the 1958 Research Airplane 

Committee Report. 

30 Ibid. 

31 “Pilot Protection for the X-15 Airplane;” email, William Ayrey, 

ILC Dover to Dennis R. Jenkins, February 4, 2010.

32 “Development of a Full-pressure Suit System,” David Clark 

Company, ASD Technical Report 61-116, May 1961. The 

contract number was AF33(616)-3903.

33 Ibid.

34 Comments from Ed Dubois at David Clark Company on a draft 

version of this manuscript, June 2010.

35 “Development of a Full-Pressure Suit System.” 

36 A. Scott Crossfield, Always Another Dawn: The Story of a Rocket 

Test Pilot (Cleveland, OH: World Publishing Co., 1960), quote on 

p. 239.

37 “Pilot Protection for the X-15 Airplane.” 

38 “Development of a Full-Pressure Suit System.” At rest, the human 

hand tends to be in a semi-closed position as the muscles relax. 

The kangaroo leather boots eventually gave way to standard Hyde 

Athletic Shoe Company Model Z100 flying boots that were modified to interface with the pressure suit. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

453

Endnotes: Chapter 6

39 “Development of a Full-Pressure Suit System;” conversation 

with Joe Ruseckas at David Clark Company, March 2009 and 

February 2010.

40 “Development of a Full-Pressure Suit System.” 

41 “Development of a Full-pressure Suit System.” Between September 18 and November 26, the S794-3C suit spent 66 hours and 

40 minutes pressurized without failure at David Clark Company, 

Firewel Company, North American, and Wright Field.

42 “Development of a Full-Pressure Suit System.” 

43 Ibid.

44 X-15 WSPO Weekly Activity Report, October 30, 1957; “FullPressure Suit Assembly,” Physiology Branch, Aero Medical 

Laboratory, WADC, 1 January 1958; memorandum, G. Kitzes, 

Assistant Chief, Physiology Branch, Aero Medical Laboratory, 

WADC, to Chief, Fighter Aircraft Division, ARDC, subject: 

Status of MC-2 Full-Pressure Altitude Suits for the X-15 Research 

Aircraft, April 10, 1958. 

45 Interview of Capt. Jerry E. Schaub X-15 WSPO, Director of 

Systems Management, ARDC, May 28, 1959, by Robert S. 

Houston, History Branch, WADC. Written transcript in the 

files at the AFMC History Office. X-15 WSPO Weekly Activity 

Report, May 2, 1958.

46 David Clark Company model number listing provided by 

Jack Bassick.

47 X-15 WSPO Weekly Activity Report, 9 May 1958; Lt. Col. Burt 

Rowen, “Biomedical Monitoring of the X-15 Program,” AFFTC 

Report TN-61-4, May 1961. Attendees included representatives of 

the Aero Medical Laboratory, X-15 Project Office, WADC Crew 

Station Office, North American, the David Clark Company, Bill 

Jack Scientific Company, and Firewel Company.

48 Memorandum, Lt. Jerry E. Schaub, X-15 WSPO, to Chief, Aero 

Medical Laboratory, WADC, August 19, 1958, subject: X-15 Fullpressure Suit Program. In the files at the AFMC History Office; 

X-15 WSPO Weekly Activity Report, September 5, 1958, and 

November 7, 1958; Lt. Col. Burt Rowen, “Human-Factors 

Support of the X-15 Program,” Air University Quarterly Review,

Air War College, Vol. X, No. 4, Winter 1958-59.

49 R.G. Bartlett, Jr., “A Study of CO2

 Build-Up With a Neck Seal 

Substituted for the Face Seal in the Full-pressure Suit Helmet,” 

Aerospace Medicine, January 1963.

50 Ibid.

51 Report, “Survey of the X-15 Research Aircraft, September 30– 

October 7, 1958,” ARDC Inspector General, not dated. 

52 “Biomedical Monitoring of the X-15 Program;” “Pilot Protection 

for the X-15 Airplane.” 

53 Vail and Willis, “Pilot Protection for the X-15 Airplane.” 

54 Ibid. How the MC-2 was pressurized in the X-15 was slightly 

different than MC-2 suits used in other aircraft.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

454

Endnotes: Chapter 6

55 X-15 WSPO Weekly Activity Report, November 21 and 

December 5, 1958, and January 9, January 30, and April 3, 

1959; memorandum, Col. F. A. Holm to Chief, Programs and 

Evaluations Office, ARDC Inspector General, February 13, 1958. 

In the files at the AFMC History Office; “Biomedical Monitoring 

of the X-15 Program.” 

56 Minutes of Meeting, X-15 Human Factors Subcommittee, 

December 30, 1960.

57 “Biomedical Aspects of the X-15 Program, 1959-1964.” 

58 Joseph A. Ruseckas, “Development of Flying Outfit, FullPressure, High Altitude, Type A/P22S-2,” Technical Documentary 

Report No. ASD-TR-61-469, March 1962. This was contract 

AF33(600)-36525.

59 Ibid. 

60 Ibid; conversation with Joe Ruseckas at David Clark Company, 

February 2010. 

61 “Development of Flying Outfit, Full-pressure, High Altitude, 

Type A/P22S-2.” 

62 Email from Jewel M. Melvin, Air Force Materiel Command, 

576 ACSS, Robins AFB, February 17, 2010.

63 Letter, Maj. Robert C. Roth, Chief Life Support Systems Branch, 

to Distribution, Subject: Full-pressure Suit Systems Management, 

not dated but approximately June 1970; conversation with Jack 

Bassick at David Clark Company, March 16, 2009.

64 Letter, Maj. Robert C. Roth, Chief Life Support Systems Branch, 

to Distribution, Subject: Full-Pressure Suit Systems Management, 

not dated but approximately June 1970.

65 Email from Jewel M. Melvin, Air Force Materiel Command, 

576 ACSS, Robins AFB, February 17, 2010.

66 Emails from Jewel M. Melvin, Air Force Materiel Command, 

576 ACSS, Robins AFB, February 17, 2010, and February 23, 

2010.

67 Ibid; conversation with Joe Ruseckas at David Clark Company, 

February 2010. David Clark Company still has the original Mark 

II helmet they used as a model.

68 “Development of Flying Outfit, Full-Pressure, High Altitude, 

Type A/P22S-2.” 

69 Ibid. Weatherbar was a commercially available material manufactured by Duplan of Canada, Ltd. David Clark Company used 

Hunter Yellow and Indian Orange.

70 X-15 Status Reports, Paul F. Bikle/FRC to H. Brown/NASA 

Headquarters, July 15, 1960; July 29, 1960; and April 3, 1961. 

In the files at the DFRC History Office; Lt. Col. Burt Rowen, 

Maj. Ralph N. Richardson, and Garrison P. Layton, Jr., 

“Bioastronautics Support of the X-15 Program,” a paper in the 

Research Airplane Committee Report on the Conference on the 

Progress of the X-15 Project, A Compilation of the Papers presented 

at the Flight Research Center, 20-21 November 1961. A slightly 

expanded version of this paper was subsequently republished as 

AFFTC Technical Report FTC-TDR-61-61, “Bioastronautics 

Support of the X-15 Program,” December 1961.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

455

Endnotes: Chapter 6

71 Kent W. Gillespie, “Outfit, Flying, Full-Pressure, High 

Altitude, Type A/P22S-2,” AFSC Functional Evaluation 

Report No. ASNRSE-61-1, June 2, 1961.

72 “Bioastronautics Support of the X-15 Program.” 

73 Ibid. 

74 “Development of Flying Outfit, Full-Pressure, High Altitude, 

Type A/P22S-2.” 

75 David Clark Company model number listing provided by 

Jack Bassick.

76 “Outfit, Flying, Full-pressure, High Altitude, Type A/P22S-2;” 

“Development of Flying Outfit, Full-Pressure, High Altitude, 

Type A/P22S-2.” 

77 Minutes of Meeting, X-15 Human Factors Subcommittee, 

December 30, 1960.

78 Minutes of Meeting, X-15 Human Factors Subcommittee, 

March 28, 1961. 

79 “Bioastronautics Support of the X-15 Program;” Comments from 

Ed Dubois and Jack Bassick at David Clark Company on a draft 

version of this manuscript, June 2010.

80 Conversation with Jack Bassick, Joe Ruseckas, Bob Banks, and 

Ed Dubois at David Clark Company, February 2010; Production 

numbers provided by Bob Banks and Ed Dubois at David Clark 

Company, May 2010.

81 Ibid.

82 Capt. Budd F. Knapp, “A/P22S-2 Full-Pressure Suit Evaluation in 

the U-2,” Air Force Flight Test Center, 1962.

83 Ibid.

84 Ibid.

85 Ibid.

86 Kent W. Gillespie, “Comparative Evaluation of USAF Standard 

A/P22S-2 and Improved A/P22S-2A High Altitude, Full-Pressure 

Flying Outfits,” Technical Report SEG-TR-65-9, April 1965.

87 David Clark Company model number listing provided by 

Jack Bassick.

88 “Comparative Evaluation of USAF Standard A/P22S-2 and 

Improved A/P22S-2A High Altitude, Full-Pressure Flying Outfits.” 

89 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009, and email from Jack Bassick on 

February 23, 2010.

90 Ibid.

91 Maj. Edward W. Kenny and Capt. Robert I. Platenberg, 

“Operational Report on the High Altitude, Full-Pressure 

Flying Outfit A/P22S-2,” February 25, 1963.

92 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

456

Endnotes: Chapter 6

93 “Comparative Evaluation of USAF Standard A/P22S-2 and 

Improved A/P22S-2A High Altitude, Full-Pressure Flying Outfits.” 

94 Supplemental Test Order, High Altitude and Supersonic Personal 

Protective Equipment, TAC Test No. 63-31A, not dated.

95 Ibid; Letter, Joe Ruseckas to John Flagg, Subject: TAC Test 

No. 63-31A Trip Report, MacDill AFB, FL, July 16–17, 1963.

96 Ibid; Letter, Joe Ruseckas to John Flagg, Subject: TAC Test 

No. 63-31A Trip Report, MacDill AFB, FL, July 16–17, 1963.

97 Kent W. Gillespie, “Comparative Evaluation of USAF Standard 

A/P22S-2 and Improved A/P22S-2A High Altitude, Full-Pressure 

Flying Outfits: Supplement 1, A/P22S-2A (Mod 1),” Technical 

Report SEG-TR-65-9, Supplement 1, April 1966.

98 Ibid. Ed Dubois and Jack Bassick at David Clark Company 

point out that although the use of rotating bearings is as 

described for aviation pressure suits, the Gemini flight suits 

used rotating bearings.

99 Comments by Bob Banks, Ed Dubois, and Jack Bassick at David 

Clark Company, June 2010.

100 John Lowery, “Zoom Climb,” Air Force Magazine, February 2005.

101 Ibid.

102 Richard T. Sears, David Clark Company, “Improvement Program 

for the A/P22S-2 Full-Pressure Flying Outfit,” Technical Report 

SEG-TR-66-65, March 1967.

103 “BFG Gets Air Force High Altitude Suit Contract,” B.F. Goodrich 

Merchandiser, Volume XV, Number 5, May 1960.

104 E-mail from Dennis Gilliam, pressure suit historian, to Dennis R. 

Jenkins, February 23, 2010.

105 Capt. Norman R. Smedes, 4750th Test Squadron, Tyndall AFB, 

Florida, “Comparative Test of Aircrew Pressure Suits,” Project 

ADC/73AD/60-11, April 1, 1961.

106 Ibid.

107 Ibid. It should be noted that the CSU-4/P had the same type of 

wrist hose.

108 Ibid.

109 Ibid.

110 Kent W. Gillespie and John R. Hochwalt, “The Design 

Requirements, Description, and Functional Operation of 

the A/P22S-4 and A/P22S-6 High Altitude, Flying Suits,” 

ASD-TR-70-58, April 1971. The contract was F33657-67C-1505.

111 Richard T. Sears, David Clark Company, “Improvement Program 

for the A/P22S-2 Full-Pressure Flying Outfit,” Technical Report 

SEG-TR-66-65, March 1967.

112 Ibid.; “The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, 

Flying Suits.” 

113 “Improvement Program for the A/P22S-2 Full-Pressure 

Flying Outfit.” 

114 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

457

Endnotes: Chapter 6

115 “The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, Flying 

Suits;” “Improvement Program for the A/P22S-2 Full-Pressure 

Flying Outfit;” Conversation with Bob Banks and Ed Dubois at 

David Clark Company, February 2010.

116 Kent W. Gillespie and John R. Hochwalt, “The Design 

Requirements, Description, and Functional Operation of 

the A/P22S-4 and A/P22S-6 High Altitude, Flying Suits,” 

ASD-TR-70-58, April 1971.

117 Ibid.

118 Conversation with Bob Banks and Ed Dubois at David Clark 

Company, February 2010; Production numbers provided by Bob 

Banks and Ed Dubois at David Clark Company, May 2010. It is 

likely the suits were used in the McDonnell Douglas F-4E Phantom IIs operated by the RAAF while awaiting delivery of their 

General Dynamics F-111Cs (most Reports indicate the F-111Cs, 

like most F-111s except the D-models, were not equipped for 

full-pressure suits).

119 E-mail from Jewel M. Melvin, Air Force Materiel Command, 

576 ACSS, Robins AFB, February 17, 2010; “The Design 

Requirements, Description, and Functional Operation of the 

A/P22S-4 and A/P22S-6 High Altitude, Flying Suits.” 

120 “The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, Flying 

Suits.” 

121 “A Brief History of the B-57 Canberra,” located at http://jsc-aircraftops.jsc.nasa.gov/wb57/history.html.

122 Ibid.

123 “The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, Flying 

Suits.” 

124 Ibid. David Clark Company records indicate 145 suits were manufactured, but this probably includes a prototype in addition to the 

144 production suits delivered to the USAF.

125 Ibid. The contract was F33657-68C-0833.

126 Ibid.

127 Reymond H. Middleton, Milton Alexander, and Kent W. 

Gillespie, “Cockpit Compatibility Studies Conducted with 

Aircrewmembers Wearing High Altitude Flying Outfits in B-57D, 

B-57F, F-104A, F-104B, F-106A, and F-106B Aircraft,” Report 

ASD-TR-70-25, December 1970.

128 Ibid.

129 Ibid.

130 “The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, Flying 

Suits.” 

131 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S1024B High Altitude Flying Outfit,” technical order 

14P3-6-131.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

458

Endnotes: Chapter 6

132 Production numbers provided by Bob Banks and Ed Dubois at 

David Clark Company, May 2010.

133 Current status of Streak Eagle from Brett A. Stolle, NMUSAF 

Research Department in an email February 17, 2010.

134 Jewel M. Melvin, Physiological Support Division, Edwards 

AFB, “Pressure Suits—How and Why,” SAFE Journal, Vol. 8, 

No. 1, 1978.

135 Otto Schueller, “Principle of the Boyle’s Law Emergency Pressure 

Suit and Their Application,” MARL-TR-67-234, December 1968.

136 Ibid.

137 Ibid.

138 “Prototype High Altitude Flying Outfit—Phase I,” Life Support 

Engineering Report ASD-TR-79-5030, October 1979.

139 Ibid; conversation with Jack Bassick, Bob Banks, and Ed Dubois 

at David Clark Company, February 2010; Production numbers 

provided by Bob Banks and Ed Dubois at David Clark Company, 

May 2010.

140 “Prototype High Altitude Flying Outfit—Phase I.” 

141 Ibid.

142 Ibid.

143 William Ayrey, ILC Space Suits & Related Products, ILC document 

number 0000-712731, Rev. A, November 28, 2007; “Prototype 

High Altitude Flying Outfit—Phase I.” 

144 “Prototype High Altitude Flying Outfit,” David Clark Company 

Technical Report DCC-263-TNR, December 12, 1978.

145 “Prototype High Altitude Flying Outfit—Phase I.” 

146 “Prototype High Altitude Flying Outfit.” 

147 “Prototype High Altitude Flying Outfit;” “Prototype High Altitude 

Flying Outfit—Phase I.” 

148 The Fypro process was developed by Travis Mills in the late 1960s.

149 “Prototype High Altitude Flying Outfit;” Conversation with Jack 

Bassick and Ed Dubois at David Clark Company, February 2010.

150 “Prototype High Altitude Flying Outfit—Phase I.” 

151 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

459

Endnotes: Chapter 7

CHAPTER 7

1

 Dennis R. Jenkins and Tony R. Landis, Lockheed Blackbirds, Vol. 

10 in the WarbirdTech Series (North Branch, MN: Specialty Press, 

2004). The U-2 had been called Angel by Johnson, so Archangel 

was a natural follow-on.

2

 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversations with Jack Bassick, Joe Ruseckas, 

and Ed Dubois at David Clark Company, February 2010.

3

 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversations with Jack Bassick, Joe Ruseckas, 

and Ed Dubois at David Clark Company, February 2010.

4

 Clarence L. Johnson, “A-12 Specification, Section V, Air Conditioning,” 1960. Released by the CIA in August 2007.

5

 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversations with Joe Ruseckas at David Clark 

Company, February 2010.

6

 Conversation with Jack Bassick at David Clark Company, 

16 March 2009; conversations with Joe Ruseckas at David Clark 

Company, February 2010; David Clark Company model number 

listing provided by Jack Bassick.

7

 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversations with Joe Ruseckas at David Clark 

Company, February 2010.

8

 David Clark Company model number listing provided by Jack 

Bassick; conversation with Jack Bassick, Joe Ruseckas, and Ed 

Dubois at David Clark Company, February 2010.

9

 David Clark Company model number listing provided by 

Jack Bassick.

10 David Clark Company model number listing provided by 

Jack Bassick.

11 David Clark Company model number listing provided by Jack 

Bassick; conversations with Jack Bassick, Bob Banks, and Joe 

Ruseckas at David Clark Company, February 2010.

12 “Breaking Through Technological Barriers,” located at https://www.

cia.gov/library/center-for-the-study-of-intelligence/csi-publications/

books-and-monographs/a-12/breaking-through-technologicalbarriers.html.

13 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009; conversations with Joe Ruseckas at David Clark 

Company, February 2010.

14 David Clark Company model number listing provided by 

Jack Bassick.

15 “Fitting, Donning, Operating and Maintenance Instructions 

for the S910F Pilots Protective Assembly,” June 30, 1964.

16 Ibid.

17 David Clark Company model number listing provided by 

Jack Bassick.

18 Ibid.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

460

Endnotes: Chapter 7

27 E-mail, Ken Collins to Dennis R. Jenkins, February 23, 2010; 

conversations with Jack Bassick and Bob Banks at David Clark 

Company, February 2010.

28 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” 

CIA Directorate of Science & Technology, Office of Special 

Activities, Report BYE-2737-44, September 23, 1966.

29 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” 

CIA Directorate of Science & Technology, Office of Special 

Activities, Report BYE-2737-44, September 23, 1966; Vojvodich 

pressure suit data provided by Bob Banks at David Clark 

Company.

30 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” 

CIA Directorate of Science & Technology, Office of Special 

Activities, Report BYE-2737-44, September 23, 1966.

31 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” 

CIA Directorate of Science & Technology, Office of Special Activities, Report BYE-8725-68, January 15, 1968; comments by Jack 

Bassick to a draft copy of this manuscript. Bill Park had the distinction of ejecting from 2 Blackbirds, A-12 Article 133 (60-6939) on 

July 9, 1964, and M-21 Article 135 (60-6941) on July 30, 1966. In 

addition to these ejections wearing suits, Ken Collins had ejected 

from Article 123 without a suit, and Bill Park and Ray Torrick had 

ejected from the M-21, with Torrick drowning after landing.

32 Brig. Gen. Paul N. Bacalis, “Program Progress Report,” April 1, 

1967–June 30, 1967, document BYE-2511-67, July 31, 1967.

33 Memorandum for Deputy for Materiel, Office of Special Activities, 

CIA, subject: Operational Considerations—Revival of OXCART, 

June 14, 1972.

19 Kent W. Gillespie and John R. Hochwalt, “The Design 

Requirements, Description, and Functional Operation of 

the A/P22S-4 and A/P22S-6 High Altitude, Flying Suits,” 

ASD-TR-70-58, April 1971.

20 David Clark Company model number listing provided by 

Jack Bassick.

21 Conversations with Jack W. Bassick at David Clark Company; 

Comments to a draft version of this manuscript by Jack Bassick.

22 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S1024B High Altitude Flying Outfit,” technical order 

14P3-6-131.

23 David Clark Company model number listing provided by 

Jack Bassick.

24 The test location was, of course, Groom Lake in southwest 

Nevada, some 83 miles north-northwest of Las Vegas. The base 

lies within the Nevada Test and Training Range and was originally 

marked on most aeronautical charts as Restricted Area 51. Other 

names used for the facility include Dreamland, Paradise Ranch, 

The Ranch, Home Base, Watertown Strip, and most recently 

Homey Airport. 

25 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” 

CIA Directorate of Science & Technology, Office of Special 

Activities, Report BYE-2737-44, September 23, 1966.

26 Email, Ken Collins to Dennis R. Jenkins, February 23, 2010. More 

information may be found in Rich Graham, SR-71 Blackbird, 

Stories, Tales, and Legends (Minneapolis, MN: Zenith Press, 2002).
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

461

Endnotes: Chapter 7

34 Ibid.

35 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009 and Joe Ruseckas at David Clark Company, 

February 2010.

36 Ibid. 

37 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S-100 High Altitude Flying Outfit,” technical manual 

TM14P3-GNS100-2.

38 Ibid.

39 Production numbers provided by Bob Banks and Ed Dubois at 

David Clark Company, May 2010.

40 Astronautics and Aeronautics, 1964: Chronology of Science, 

Technology, and Policy (Washington, DC: NASA SP-4005, 1965), 

pp. 292.

41 The RS-71 designation was a logical follow-on to the RS-70 (RS 

for reconnaissance-strike) designation given to the last proposed 

production version of the North American XB-70A Valkyrie.

42 Joe Ruseckas, “Technical Proposal for the S901J Pilots Protective 

Assembly,” February 8, 1965; “Purchase Specification: Pilots 

Protective Assembly GN-S901J,” November 29, 1966.

43 Conversations with Jack Bassick and Bob Banks at the David 

Clark Company, February 2010.

44 Joe Ruseckas, “Technical Proposal for the S901J Pilots Protective 

Assembly,” February 8, 1965; David Clark Company model number listing provided by Jack Bassick.

45 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S901J Pilots Protective Assembly,” technical manual 

TM14P3-GN:S901J:6-2.

46 Ibid. The “hose-excess” pocket is where suit technicians secure any 

extra length of oxygen hose to keep it from becoming entangled in 

the cockpit environment. 

47 Ibid.

48 “Purchase Specification: Pilots Protective Assembly GN-S901J,” 

November 29, 1966; comments from Jack Bassick on a draft 

version of this manuscript.

49 David Clark Company model number listing provided by 

Jack Bassick; Kent W. Gillespie and John R. Hochwalt, “The 

Design Requirements, Description, and Functional Operation 

of the A/P22S-4 and A/P22S-6 High Altitude, Flying Suits,” 

ASD-TR-70-58, April 1971.

50 “Operations and Maintenance Instructions with Illustrated 

Parts Breakdown: S901J Pilots Protective Assembly;” “Purchase 

Specification: Pilots Protective Assembly GN-S901J,” 

November 29, 1966; comments from Jack Bassick on a draft 

version of this manuscript.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

462

Endnotes: Chapter 7

51 “Technical Proposal for the S901J Pilots Protective Assembly;” 

“The Design Requirements, Description, and Functional 

Operation of the A/P22S-4 and A/P22S-6 High Altitude, 

Flying Suits.” 

52 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report,” David Clark Company Report 

DCR-3453, October 2006.

53 Nopcofoam was developed by Nopco Chemical Company and 

is used extensively in the manufacture of furniture, bedding, and 

automotive seating. Nopco had begun as the National Oil Products Company and was later purchased by the Diamond Alkali 

Company, which merged with Shamrock Oil to become 

Diamond Shamrock Corp. In 1987, Diamond Shamrock split 

into 2 companies, with the former Nopco division going to 

Maxus Energy Corp.

54 “Purchase Specification: Pilots Protective Assembly GN-S901J.” 

55 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S901J Pilots Protective Assembly.” Pittsburgh Plate 

Glass Company (PPG) has long been a leader in the development 

of glass and paints.

56 “Purchase Specification: Pilots Protective Assembly GN-S901J.” 

57 OEP-23, Attachment 2, U-2R Addendum. Not dated; email, 

Malcom V. “Mike” Todd to Dennis R. Jenkins, February 18, 2010.

58 Brig. Gen. Paul N. Bacalis, “Program Progress Report,” April 1, 

1967–June 30, 1967, document BYE-2511-67, July 31, 1967.

59 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report,” David Clark Company Report DCR-3124-00, 

February 28, 1992.

60 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report,” David Clark Company Report 

DCR-3453, October 2006.

61 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S1010A Pilots Protective Assembly,” technical manual 

TM14P3-GNS1010A-2; Conversations with Jack Bassick, Bob 

Banks, and Ed Dubois at David Clark Company, February 2010.

62 Conversations with Jack Bassick, Bob Banks, and Ed Dubois 

at David Clark Company, February 2010; Production numbers 

provided by Bob Banks and Ed Dubois at David Clark Company, 

May 2010.

63 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report.” 

64 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report,” David Clark Company Report DCR-3124-00, 

February 28, 1992; “Operations and Maintenance Instructions with 

Illustrated Parts breakdown, Pilots Protective Assembly, GNS1030,” 

technical manual TM14P3-GN:S1030-2, May 1, 1979.

65 Donn A. Byrnes and Kenneth D. Hurley, Blackbird Rising: 

Birth of an Aviation Legend (Los Lunas, NM: Sage Mesa 

Publications, 1999).

66 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

463

Endnotes: Chapter 7

67 Production numbers provided by Bob Banks and Ed Dubois at 

David Clark Company, May 2010.

68 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

69 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report.” 

70 Conversation with Jack Bassick, Bob Banks, and Ed Dubois at 

David Clark Company, February 2010; Production numbers 

provided by Bob Banks and Ed Dubois at David Clark Company, 

May 2010.

71 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report.” 

72 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

73 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

74 Production numbers provided by Bob Banks and Ed Dubois at 

David Clark Company, May 2010.

75 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

76 Ibid.

77 Ibid.

78 Gore-Tex is a waterproof/breathable fabric, and a registered trademark of W.L. Gore & Associates. It was co-invented by Wilbert 

L. Gore (1912–1986), Rowena Taylor, and Gore’s son, Robert W. 

Gore. Robert Gore was granted U.S. Patent 3,953,566 on April 

27, 1976, for a porous form of polytetrafluoroethylene (PTFE) 

with a micro-structure characterized by nodes interconnected 

by fibrils. Robert Gore, Rowena Taylor, and Samuel Allen were 

granted U.S. Patent 4,194,041 on March 18, 1980, for a “waterproof laminate.” For its invention, Robert W. Gore was inducted 

into the National Inventors Hall of Fame in 2006.

79 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

80 Daniel M. Barry and John W. Bassick, “NASA Space Shuttle 

Advanced Crew Escape Suit Development,” SAE Technical 

Paper 951545, 25th International Conference on Environmental 

Systems, July 10–13, 1995.

81 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” The term “vanishing” is standard industry terminology for vendors, often small mom-and-pop shops, that suddenly 

go out of business or stop making highly specialized parts.

82 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

83 Ibid comments by Jack Bassick on a draft of this manuscript.

84 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” The contract was F09604-90-C-0006.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

464

Endnotes: Chapter 7

85 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” PBI is used extensive in firefighters ensembles. 

According to the manufacturer, “PBI (polybenzimidazole) stable 

fiber is an organic fiber that provides thermal stability for a wide 

range of high temperature applications. PBI fiber will not burn 

in air, it does not melt or drip, and it will retain its strength and 

flexibility after exposure to flame.” For further details, see http://

www.pbigold.com/en/applications/apparel_fireservice.

86 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

87 Ibid.

88 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S1034 Pilots Protective Assembly.” 

89 The product used by David Clark Company is Serenity by TENA, 

a division of Svenska Cellulosa Aktiebolaget (SCA); conversation 

with Jack Bassick, Bob Banks, and Ed Dubois at David Clark 

Company, February 2010.

90 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

91 Ibid.

92 “Operations and Maintenance Instructions with Illustrated Parts 

Breakdown: S1034 Pilots Protective Assembly” technical manual 

TM14P3-GNS1034-2.

93 Malcom V. Todd, Lockheed Advanced Development Projects 

Life Support Division, “Summary of S1034 Pilots Protective 

Assembly Evaluation at Palmdale,” Lockheed LS-FTP-91-1, 

January 28, 1992. Sasine currently holds, along with James T. 

Allen, the world speed record over a recognized course for FAI 

Class C-1e landplanes, flying a prototype Adam Aircraft A700 

on July 7, 2006.

94 “Summary of S1034 Pilots Protective Assembly Evaluation 

at Palmdale.” 

95 Ibid.

96 “S1034 Pilots Protective Assembly, Development & Qualification 

Final Report.” 

97 Ibid.

98 Conversations with Jack Bassick, Bob Banks, and Dan McCarter 

at David Clark Company, February 2010; Production numbers 

provided by Bob Banks and Ed Dubois at David Clark Company, 

May 2010.

99 “S1034E PPA Helmet Engineering Development and 

Qualification: Final Report.” 

100 Ibid.

101 J. Falck, “Next Generation Helmet Completion Letter,” Lockheed 

Martin Aeronautics Company Report U2-FTPL-000049-00-CL, 

December 18, 2005.

102 E-mail, Jack Bassick to Dennis R. Jenkins, March 3, 2010.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

465

Endnotes: Chapter 8

CHAPTER 8

1

 For the complete history of the program, see, for instance, 

Dennis R. Jenkins, Space Shuttle—The History of the National 

Space Transportation System: The First 100 Missions (North Branch, 

MN: Specialty Press, 2001).

2

 “About SpaceAge Control,” located at http://www.spaceagecontrol.

com/Main/About. The contract was NAS9-11280.

3

 Jimmy B. Graves, Life Support Systems Manager, Space Age 

Control, “Intravehicular Space Suit Final Report,” contract 

NAS9-11280, SAC document No. 100218, March 1972.

4

 Ibid.

5

 Jimmy B. Graves, Life Support Systems Manager, Space Age 

Control, “Intravehicular Space Suit Assembly Program Phase C 

Design Verification Report, contract NAS9-11280, SAC document No. 100215-2, February 29, 1972.

6

 William Ayrey, “ILC Space Suits & Related Products,” ILC 

document number 0000-712731, Rev. A, November 28, 2007.

7

 Ibid; Dixie Rinehart, “Real Mobility,” ILC Reporter, December 

1970.

8

 Grujica S.Ivanovich, Salyut—The First Space Station: Triumph 

and Tragedy (London: Praxis, 2008).

9

 “Space Shuttle EVA/IVA Support Equipment Requirements Study,” 

contract NAS9-12506, Hamilton Standard Report SP-01T73, 

April 30, 1973.

10 R.J. Copeland, P.W. Wood, Jr., and R.L. Cox, “Study of Space 

Shuttle EVA/IVA Support Requirements,” contract NAS9-12507, 

Vought Report T-192-RP05, April 30, 1973.

11 James D’Andrade and John McMullen, “Requirements Study 

for Space Shuttle Pressure Suits,” contract NAS9-12507, ILC 

Industries, Inc. Report ER-051-01, December 19, 1972.

12 Ibid.

13 Ibid.

14 Ibid

15 R.J. Copeland, P.W. Wood, Jr., and R.L. Cox, “Study of Space 

Shuttle EVA/IVA Support Requirements," contract NAS9-12507, 

Vought Report T-192-RP05, April 30, 1973.

16 “Space Shuttle EVA/IVA Support Equipment Requirements Study,” 

contract NAS9-12506, Hamilton Standard Report SP-01T73, 

April 30, 1973.

17 “ILC Space Suits & Related Products.”

18 William Elkins, “High Pressure Space Suit Glove Program,” 

Acurex Corporation, contract NAS2-7008, NASA contractor 

Report CR-114535, January 1973; William Elkins, “Phase II, 

III. & IV 8-PSI Pressure Glove, Acurex Corporation, contract 

NAS2-7610, NASA contract Report CR-114755, January 1975.

19 For further information on the ALT flights, see Space Shuttle: 

The History of the Space Transportation System.
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

466

Endnotes: Chapter 8

20 Daniel M. Barry and John W. Bassick, “NASA Space Shuttle 

Advanced Crew Escape Suit Development,” SAE Technical 

Paper 951545, 25th International Conference on Environmental 

Systems, July 10–13, 1995.

21 Contract NAS9-15105 and Statement of Work (SOW), 

November 15, 1976; comments by Jack Bassick on a draft 

version of this manuscript.

22 Contract NAS9-15649 and Statement of Work (SOW), 

August 7, 1978.

23 Ibid.

24 Conversation with Jack Bassick and Bob Banks at David Clark 

Company, February 2010.

25 Letter, James V. Correale, Chief, Crew Systems Division, to 

Lt. Col. Calvin Greer, Det 6, 2762 Logistics Squadron, Norton 

AFB, October 27, 1978. 

26 “NASA S1030A Ejection Escape Suit (EES),” a serial number list 

supplied by Bob Banks and Ed Dubois at David Clark Company.

27 E-mail, Thomas W. Bowen, 9th PSPTS/CD at Beale AFB, 

February 17, 2010.

28 E-mail, James P. Bagian, February 28, 2010.

29 E-mails from James P. Bagian and Jack Bassick at the David Clark 

Company, June 25, 2010.

30 James P. Bagian and L.W. Schafer, “Comparison of Current 

Shuttle and Pre-Challenger Flight Suit Reach Capability During 

Launch Accelerations,” Aviation, Space, and Environmental 

Medicine, July 1992.

31 Kalikiano Kalei, “Flight Helmets: Romance of the Gear,” 

located at http://www.authorsden.com/visit/viewarticle.

asp?AuthorID=77566&id=37015; http://www.best-of-flightgear.dk/

hgu15hel.htm.

32 Kalikiano Kalei, “Flight Helmets: Romance of the Gear,” 

located at http://www.authorsden.com/visit/viewarticle.

asp?AuthorID=77566&id=37015.

33 Conversation with Lucien Van Oosten, Gentex Corporation, 

March 9, 2010.

34 Ibid.

35 “Crew Systems Reference Manual: Volume 1—Crew Escape,” 

JSC-25909, Vol. 1, Rev A, April 15, 2005.

36 “Report of the Presidential Commission on the Space Shuttle 

Challenger Accident,” June 6, 1986.

37 Ibid.

38 Ibid.

39 Letter, James C. Fletch, NASA Administrator, to The President, 

July 14, 1986, with a copy of “Actions to Implement the 

Recommendations of the Presidential Commission on the Space 

Shuttle Challenger Accident.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

467

Endnotes: Chapter 8

40 “STS Crew Egress and Escape Study,” NASA document 

JSC-22275, 1986.

41 Ibid.

42 “National Space Transportation System Reference” June 1988.

43 Ibid.

44 “S1032 Launch Entry Suit: Development and Production Report,” 

David Clark Company Report DCR-3127-00, June 30, 1992. 

The LEMSC prime contract was NAS9-15800.

45 Ibid.

46 Ibid.

47 “Columbia Crew Survival Investigation Report,” NASA 

SP-2008-565, 2008.

48 Daniel M. Barry and John W. Bassick, “NASA Space Shuttle 

Advanced Crew Escape Suit Development,” SAE Technical 

Paper 951545, 25th International Conference on Environmental 

Systems, July 10–13, 1995.

49 “S1032 Launch Entry Suit: Development and Production Report,” 

David Clark Company Report DCR-3127-00, June 30, 1992.

50 “S1032 Launch Entry Suit: Development and Production Report.” 

51 Ibid. The final sizes were one large-long and one small-short flightcertified suits, and one medium-short, one medium-regular, one 

medium-long, and one large-regular training suits for STS-26R.

52 “S1032 Launch Entry Suit: Development and Production Report.” 

53 Ibid.

54 Lauren E. Schafer, Sudhakar L. Rajulu, and Glenn K. Klute, “A 

Comparison of Two Shuttle Launch and Entry Suits: Reach Envelope, Isokinetic Strength, and Treadmill Tests,” SAE paper 921154, 

presented at the 22nd International Conference on Environmental 

Systems, Seattle, Washington, July 13–16, 1992.

55 J. W. Kaufman, et. al., “Cold Water Evaluation of NASA Launch 

Entry Suit (LES),” Naval Air Development Center report 

NADC-88017-60, July 1, 1988.

56 “S1032 Launch Entry Suit: Development and Production Report.” 

57 By now, the Lockheed Engineering and Management Services 

Company (LEMSC) had changed its name to Lockheed 

Engineering & Sciences Company (LESC).

58 James P. Bagian and Lauren W. Schafer, “Comparison of Current 

Shuttle and Pre-Challenger Flight Suit Reach Capability During 

Launch Accelerations,” Aviation, Space, and Environmental 

Medicine, July 1992.

59 Ibid.

60 Ibid.

61 Ibid.

62 “S1032 Launch Entry Suit: Development and Production Report.” 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

468

Endnotes: Chapter 8

63 “NASA Space Shuttle Advanced Crew Escape Suit Development;” 

“A Comparison of Two Shuttle Launch and Entry Suits: Reach 

Envelope, Isokinetic Strength, and Treadmill Tests.” 

64 Conversation with Jack Bassick at David Clark Company, 

March 16, 2009.

65 Conversation with Bob Banks and Dan Barry at David Clark 

Company, February 2010.

66 “Improved Launch Entry Suit S1035 SOW, Development/

Qualification Support,” Lockheed statement of work 

LESC-SOW-28606, August 1, 1990; “NASA Space Shuttle 

Advanced Crew Escape Suit Development.” 

67 “NASA Space Shuttle Advanced Crew Escape Suit Development.” 

68 Conversation with Jack Bassick, Bob Banks, and Dan Barry at 

David Clark Company, February 2010.

69 “NASA Space Shuttle Advanced Crew Escape Suit Development;” 

“Columbia Crew Survival Investigation Report.” 

70 Phil Landis and Phil Hooper, “Assessment of the S1035 Advanced 

Crew Escape Suit for Use in the Space Launch Initiative program,” 

Lockheed Martin Space Operations Report LMSEAT-34099, 

January 16, 2003.

71 “Columbia Crew Survival Investigation Report.” 

72 Ibid.

73 “Orbiter Vehicle End Item Specification for the Space Shuttle 

System, Part 1, Performance and Design Requirements,” 

Boeing MJ070-0001-1F, Rev. F, 27 July 2009.

74 “Assessment of the S1035 Advanced Crew Escape Suit for Use 

in the Space Launch Initiative program;” Production numbers 

provided by Bob Banks and Ed Dubois at David Clark Company, 

May 2010.

75 Conversation with Jack Bassick, Bob Banks, and Ed Dubois at 

David Clark Company, February 2010.

76 “Columbia Crew Survival Investigation Report.” 

77 Ibid.

78 “Similarity” is a verification process where an item is shown to 

work based on its similarity to another item that has passed a rigorous testing regime. In most cases, only characteristics of the item 

that are significantly different are examined in any detail.

79 “Columbia Crew Survival Investigation Report.” 

80 Ibid.
.
470

index
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

471

Index: A

Index

Numbers in bold indicate pages with illustrations or tables

A

A3J (A-5) Vigilante, 230

A6M Zero, 85, 94

A-7 oxygen mask, 429n108

A-8 oxygen mask (Boothby-Lovelace-Bulbulian oxygen 

masks), 91, 429n108

A-12 (Emerson) demand regulators, 123, 124

A-12 reconnaissance aircraft (Oxcart) accidents in, 312, 

315–16, 410

Article 121, 311

 Article 123, 312, 460n31

 Article 126, 312

 Article 128, 312

 Article 129, 316

 Article 133, 460n31

 black painted surfaces, 311

 code names, 302, 304, 324

 Convair design, 302

 cost of development and manufacturing of aircraft, 302

 cost of suits for, 308

 David Clark Company suits for, 279

 design and development of, 302

 ejection seats, 304, 314, 316, 324

 ejections from, 304–5, 304, 312, 314, 460n31

 engines, 312

 first flight, 311 regeneration package and return to operations, 316
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

472

Index: A

Abel, Rudolf (Vilyam Genrikhovich Fisher), 156

acceleration

 blood pressure and, 43, 73

 centrifuge for study of effects, 74–80, 75, 77, 78, 79

 fighter aircraft, air combat maneuvers, and, 113–14

 G-loads (Gz) and, 43, 72–74, 72, 80–83, 81, 424n10

 lateral (Gy), 72, 73

 measures of, 72–73

 physiological effects and risks, 72–74, 72, 80–83, 81, 

 425n15

 research on effects, 80–83

 transverse (Gx), 72, 73

 vision and, 43, 73, 80, 81, 425n15

Acurex Corporation, Aerotherm Division, 373–74

Adam, Maurice James, 41, 419n80

Adam Aircraft A700 prototype, 464n93

Adams, Harold “Buck,” 330

Adams, Michael J., 278

ADC. See Air Defense Command (ADC)

Advanced Crew Escape Suits. See S1035 Advanced Crew 

Escape Suit (ACES)

Advanced Technology Anti-G Suit (ATAGS), 112–13, 

116–18, 119

aeromedical and physiological research, 41–43, 81, 89–92

Aero Medical Equipment Laboratory (AMEL), 206, 209

Aero Medical Laboratory, Wright Field

 Acceleration Unit, 77

 Benson and research at, 43

 counter-pressure clothing, research on, 124

 CSU-2/P suits, 165–67

 CSU-4/P suits, 169, 171

 face seals versus neck seals, 258–59

 full-pressure suit development, 216, 237, 239–41

 funding for suits, 258

 G-suit development, 95, 97

 latex rubber suit testing, 242–43

 Lovelace research at, 91

 MB-1 suit development and testing, 141, 144, 145, 146

 MC-2 suit testing, 252, 253–56, 453n41

 MC-3 suit development, 147–48

 Mercury program suits, research on, 233

 Model H suit testing, 240–41

 name of, 425n24, 437n20

 Omni-Environment Suit testing, 184, 237, 239

 pressure-breathing masks, development of, 123–24

 pressure-breathing research, 122, 123, 124

 pressure-suit research, 45, 49, 50–51, 52, 53–54, 56, 68

 sizing of flying suits, 134, 136

 T-1 suit testing, 136

 test subjects, 145

 USAF suits, development of, 216

 USC laboratory, relationship with, 125

 X-15 program suits, 244–46

XMC-2-DC suit testing, 248, 249, 252–53

Aeromedical Museum, Brooks Air Force Base, 417n37

Aeromedical Research Unit, Wright Field, 43, 97, 425n24

Aero Medical Unit, Mayo Clinic, 90–91, 437n20

Aeronautical Systems Command, 286

Aeronautical Systems Division, Wright-Patterson Air 

Force Base, 262, 266, 267, 295–96, 299

Aerospace Medical Division, 425n24

Aerospace Medical Laboratory, 425n24

Aerospace Medical Research Laboratory and Systems 

Engineering Group, 6570th, 283

Aerospace Protective Technology project (Project 7164), 

293–95

Aerospace Research Pilots School (Test Pilot School), 265, 

278

Aerotec Company, 217

Aerotech Industry Corporation, 110

Aerotherm Division, Acurex Corporation, 373

aether, 16, 413n6

AF-12 interceptor. See YF-12A/AF-12 interceptor aircraft

AFFTC. See Air Force Flight Test Center (AFFTC)

AIC-10 communications system, 139, 228, 274

AIM-47 (GAR-9/GAR-X) Falcon missiles, 307, 308, 378

air, weight of, 16, 17

air-conditioning equipment

 conditioned air supply equipment (CASE), 224, 226

 crew vans, 349

 portable, 225–26, 225, 275, 294

 RAAF air-conditioned vans, 84

 readyrooms, air-conditioned, 224, 226

 suiting-up van, 227

 TAC Trucks, 226

aircraft

 advances in and pressure suit requirements, 121, 237, 

238, 239, 243

 artificial horizon instruments, 80–81

 cockpits, pressurized, 121, 259, 377–78

 manufacturers of, 362

 piston-powered aircraft, 142, 237, 301

 pressurized cabin, first, 237

 prohibition of jumping from, 26

 Round One X-planes, 244

 Round Two X-planes, 244

 standardization of suit designs for, 105–6, 109–10, 

 135, 258

See also engines

aircraft carriers

 conditioned air supply equipment (CASE) for 

 readyroom, 224
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

473

Index: A

 dressing rooms, 225 full-pressure suits, comparison of, depot for suit maintenance, testing, and logistical 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

474

Index: A

ALSOR (Air Launched Sounding Rocket), 229

altitude

aeromedical and physiological research, 41–43

 aircraft performance increases and, 237, 238, 239

 air pressure and weight and, 17

 Armstrong Line, xi, 22, 75

 atmospheric data by, 19

 atmospheric pressure and, 20

 engine performance and, 142, 237

 oxygen, altitude, and physiological impairment, 20, 

 21, 22–23, 41–43, 122

 oxygen requirements for consciousness, 21

 partial pressure of gases and, 21

 pressure breathing for altitude (PBA), 113

 speed of flight and, 29

 suit performance requirements, vi

 temperature and, 18, 19, 20, 23, 25

 time of useful consciousness and, 19, 22

altitude chambers

 BABM suit testing, 56, 59

 Brooks AFB, 112

 Douglas Aircraft, 199, 200, 201–2, 204, 211

 Harvard University, 75

 Mayo Clinic chamber, 51–52, 55, 181

 McDonnell Aircraft Company, 225

 Medical Research Laboratory/School of Aviation 

 Medicine, 42

 NACEL chamber, 179

 Navy chamber, 61, 63, 66

 Post pressure suit testing, 28, 31, 33–34

 Ridge pressure suit testing, 27

 USC chamber, 128

 Wright Field chamber, 28, 31, 57, 61, 68, 124, 155, 

 17n37

Altitude Protective Garment (APG), 173–74

altitude suits, ix

AMAL (Aviation Medical Acceleration Laboratory) 

230–31

AMEL (Aero Medical Equipment Laboratory), 206, 209

Ames Research Center, 154, 321, 371–72, 373

AN/ASG-18 fire control system, 308

Andonian, Harry, 271

anesthesia apparatus, development of, 91

Angel, 150, 459n1. See also U-2 spy plane “Dragon Lady”

animal research, 128

Antietam, 232

Anti-G Control Valve (AGCV), 376

anti-G straining maneuvers, x, 73–74, 94, 113–14, 115

anti-G suits. See G-suits/anti-G suits

anti-suffocation feature, xii, 267, 299, 310, 319, 334, 

361, 395

Antonelli, Tony, 404

AOH-1 (Aviator Oxygen Helmet), 378

A/P22P-16 COMBAT EDGE ensemble, 114

A/P22S-1 full-pressure suit, 262

A/P22S-2 full-pressure suit

ADC testing and use, 272, 273–74, 279–83, 281

 Air Force suits, comparison of, 329

 A/P22S-2A (Mod 1) version, 274, 276–77, 283, 284

 A/P22S-2A version, 274, 277, 283, 284

 approval of by USAF, 267

 back kits, 273, 277

 biomedical data collection, 268

 boots, 263, 266, 273, 276, 277

 colors of exterior covers, 276, 277, 454n69

 comfort of, 272, 273, 278, 280

 communications, 274

 custom fitting of, 277–78

 designation system for suits, 262

 development and specifications, 140, 173, 262–63, 

 266–67, 268

 distribution and use of, 140, 262, 270–71, 277–78, 

 282–83

 donning and doffing, 268, 271, 272, 278–79, 280, 

 283

 ensemble components, 268, 268

 exterior covers, 263, 267, 276, 277, 277, 454n69

 F-102 testing and use, 271, 279–81, 281, 283

 F-104/104B testing and use, 289–90

 F-106/F-106B testing and use, 267, 271, 272, 

 273–74, 289–90

 fabrics and materials, 263, 267, 454n69

 face seals, 259, 266, 268, 269, 283

 gloves, 263, 266, 267, 268, 269, 272, 273, 274, 

 276–77, 278–79, 280

 Haderlie accident, 278–79

 helmets, 263, 266, 267, 268, 269, 272, 274

 improvements to design, 268

 interceptor aircraft use, 271, 272, 273–74

 Israeli Defense Forces use, 295

 lifting body program use, 275, 276, 277, 277

 Link-Net fabric use, 263, 269

 MAC/WB-57F pilots’ evaluation of, 286–87

 model numbers of suits, 277

 neck ring, 263

 number of suits produced, 270–71, 279

 oxygen masks, systems, and supply, 266, 271, 272

 parachutes, 271, 273

 restraint layer, 263, 266, 269

 rocket-sled evaluations, 267

 rotating wrist bearings, 277, 456n68

 S906 suits, 268–69, 277
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

Index: A

475

 S926/S926A suits, 268, 277 gloves, 280

 Goodrich as manufacturer, 279

 modified Mark IV pressure suits, 233, 272, 279, 280, 

280

 neck ring, 282

 TAC use, 274

 underwear, 282

A/P22S-4 full-pressure suit

 Air Force suits, comparison of, 329

 color of, 286

 designation system for suits, 262

 development and specifications, 279, 283, 287

 distribution and use of, 284, 286

 ensemble components, 286

 exterior covers, 284

 gloves, 284, 286

 helmets, 284, 286

 Link-Net fabric, 283, 284

 neck ring, 284

 number of suits produced, 286

 oxygen masks, systems, and supply, 284

 pocket locations, 284

 restraint layer, 283–84

 S901J suit compared to, 287

 sizing of, 287

 wrist rings, 278–79, 283, 284

 zippers and fasteners, 283

A/P22S-6/6A full-pressure suit

 Air Force suits, comparison of, 329

 A/P22S-6A version, 290–91, 291

 boots, 289, 290, 294

 colors of, 290, 294

 comfort liner, 290

 designation system for suits, 262

 development and specifications, 173, 287, 290–91

 distribution and use of, 291–93, 292

 ensemble components, 289, 290

 exterior covers, 290

 F-15/F-15A/F-15B testing and use, 176, 291–93, 292

 F-102 use, 291

 F-104/104B testing and use, 289–90, 291

 F-106/F-106B testing and use, 289–90, 291

 face seals, 290

 gloves, 289, 290, 294

 helmets, 289, 290, 291, 317–19, 318, 319, 361

 Israeli Defense Forces use, 288, 289, 295

 MAC requirements, 287

 number of suits produced, 286, 287, 291, 457n124

 oxygen masks and systems, 290, 361

 replacement of, 361

 replacement of for USAF use, 295, 299

 S901J suit, similarities to, 287

 service-life expiration, 295

 shipping containers, 289

 sizing of, 287

 suit controllers, 291

 testing of, 176

 underwear, 290

 urine-collection system, 290, 311

 visors, 289

 WB-57F program testing and use, 287, 289–90, 289, 

 291, 293, 294

 wrist rings, 284

 XB-70/XB-70A use, 291

A/P22S designation system, 262

APG (Altitude Protective Garment), 173–74

Apollo program

A7L/A7LB suit, 369, 371, 372
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

476

Index: A | B

 capsule for, 365

 centrifuge for pilot training, 78, 80

 gloves, 296

 ILC suits, 232, 246, 296, 362, 367, 369, 371, 372

Approach and Landing Test flights, 374–75

Aquatone project, 150. See also U-2 spy plane 

“Dragon Lady”

Archangel, 302, 459n1. See also A-12 reconnaissance 

aircraft (Oxcart)

Area 51 (Restricted Area 51), vii, 150, 460n24

argon, 18

Aristotle, 15, 16, 413n4

Arlauskas, Rose, 103, 242

Armstrong, Harry George

 animal research by, 128

 British high-altitude flights, survey of, 45

 education and career of, 42, 74–75

 physiological effects and risks, research on, 42–43, 

 74–75

 protective equipment, development and testing of, 45, 

 57, 75, 77, 81

 recognition for contributions of, 90

Armstrong, Neil A., 259, 260, 382

Armstrong Line, xi, 22, 75

Army Air Service, U.S.

Clark-Dreyer Oxygen System, 41–42

 operational period for, 416n16

 Ridge pressure suit, 27–28

Army/Army Air Corps, U.S.

 air missions, 301

 BABM suits, 46–47, 48, 49–50, 49, 51–52, 51, 53, 

 55, 56, 58, 59

 Bell pressure suit, 46

 Berger Brothers G-suit use, 94, 95, 431n132

 cost of pressure suits, 44, 45, 47, 49, 52, 57

 David Clark cutaway suit use, 105, 106

 designation system for suits, 44, 430n123

 G-2 G-suit, 104

 Goodrich suits, 43–44, 45–46, 47, 51, 52–53, 54, 

 56–57, 60, 68

 Goodyear suits, 43, 44, 47, 52–55, 60, 68, 420n102

 G-suit development, 43–44

 MX projects. 

See MX research and development projects

 National Carbon Company suits, 44, 50–51

 operational period for, 416n16

 Post pressure suit, 31–32, 43

 pressure suit development, 237, 362

 pressure suit development, coordination of research 

 for, 52–53

 pressure suit development, failure of, 68, 69

 pressure suit requirements, 44

 U.S. Rubber suits, 43–45, 49, 52–53, 54, 420n90

Army Signal Corps Medical Research Laboratory, 31, 

41–42. See also School of Aviation Medicine (Army)

Arnold, Henry H. “Hap,” 45

ARO Corporation/ARO Equipment Company, 124, 154

around-the-world flights, 29, 416n25

Arrowhead Products Division, Federal-Mogul-Bower

Arrowhead AE-83 suit (Mark IV suits), 227, 230–31, 

 279

 Garment, Upper Hollywood (GUH), 227

 garment, upper stratosphere (GUS) Mark III suit, 222, 

 226–27

 pressure suit development by, 362

Arterial Occlusion Suit (AOS), 100, 101–2, 101, 103

artificial horizon instruments, 80–81

ATAGS (Advanced Technology Anti-G Suit), 112–13, 

116–18, 119

Atlantis (OV-104), 384

Atlantis Warrior program, 114

atmosphere

 altitude and atmospheric data, 19

 atmospheric pressure, 16–17, 19, 20–22

 definition of, 18

 percentages of atmospheric gases, 18

 purpose of, 18

 Strato-Lab project to study, 231–33

 structure of, 18–20

Austin, F.H., Jr., 224

Australia

G-suit development, x, 89

 MacRobertson Race, 29, 33, 417n28, 418n43

 University of Sydney centrifuge, 75, 75, 84

See also Royal Australian Air Force (RAAF)

Australian National Health and Medical Research 

Council, 75

Autoflug GmbH, 115

Autoflug Libelle GmbH, 115

Aviation Medical Acceleration Laboratory (AMAL), 

230–31

aviator bends (decompression sickness), xi, 21, 22, 23, 26, 

132, 141

Aviator Oxygen Helmet (AOH-1), 378

Avro (A.V. Roe of Canada, Ltd.), 141

B

B-8 goggles, 127, 130

B-12 constant-flow oxygen mask, 62

B-17/B-17E/B-17F Flying Fortress

 BABM suit design for, 46
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

477

Index: B

 BABM suit testing, 47 shirtsleeve environments, 156 Model 11 suit, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

478

Index: B

Balloon Hangar centrifuge, 43, 74, 75, 77 Bell Aircraft G-suits, 83, 84, 86, 88, 92–95, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

479

Index: B

 helmets, 51, XH-1/XH-1C pressure suit, jerkin and jerkin-based ensembles, 175
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

480

Index: B

high-altitude flight and natural breathing process, x, 

21–22

lung collapse, 123

oxygen pressure requirements for natural breathing, 20

partial-pressure suits and breathing process, xi, 21

prebreathing requirements, 43, 271, 371, 382

pressure breathing for altitude (PBA), 113

pressure breathing for G (PBG), 113

pressure breathing/positive pressure breathing (PPB), 

21–22, 23, 30, 122–24

pressure breathing research at USC, 126

breathing masks. See oxygen masks, supply, and systems; 

pressure-breathing masks

Brett, George H., 45

Bridgeman, William B., 139–40, 167

Briefcase Suit, 369, 369, 370

Bristol 138a aircraft, 41

British Aircraft Corporation TSR.2 aircraft, 174

Brock, William S. “Billy,” 33

Brooks Air Force Base (AFB)/Brooks Field

Aeromedical Museum, 417n37

altitude chamber, 112

Armstrong Laboratory, testing at, 117–18, 119

human centrifuge, 112–13, 396–98

Libelle G-Multiplus G-suit testing, 115

School of Aerospace Medicine. See School of Aerospace 

Medicine (Air Force) 

School of Aviation Medicine, 42, 74

TLSS testing, 112–13

training at, 42

Brown, Curtis L., 403

BT-13A Valiant/SNV-1 trainer, 63

Buckley Field, Colorado Air National Guard Base, 273

Bulbulian, Arthur H., 47, 90, 91

General Electric suits, 67

Goodrich suits, 47, 51, 218

Henry Suit (S-1 partial-pressure suit), 128

Mark IV pressure suit, 230, 231

MC-4/4A partial-pressure suit, 159

protection provided by, xi

Rocky 911 boots, 401, 402

S901 full-pressure suit, 304

S901J Pilots Protective Assembly, 329

S1035 Advanced Crew Escape Suit, 401, 402

spurs, 273

U.S. Rubber suits, 47

XMC-2-DC suits, 252, 452n38

Bosee, Roland A., 209, 227

Bowen, Steve, 404

Bowen, Tom, 378

Boyle, Joseph, III, 293

Boyle, Robert, 17–18

Boyle’s Law, 17–18, 295

Boyle’s Law Suit, 293–95

Brand, Vance D., 376

Branshaw, Charles E., 68

Brauer Knitting Company A48C stretch nylon fabric, 167

B/RB-66 Destroyer, 149, 156

breathing

altitude, consciousness, and oxygen requirements, 21

anti-G straining maneuvers, 73–74, 113–14, 115

automatic suit controllers and, 216–17

COMBAT EDGE and breathing process, 113

compensated metabolism apparatus, 122

exhalation, x, 22, 121, 123

face seals versus neck seals, 258–59

full-pressure suits and breathing process, xi, 21

Blood-Pressure in Surgery (Crile), 71

Boeing

BABM suits, 46–47, 55, 58, 59, 179 

See also BABM suits 

pressure suit development and testing, 46, 68

Strato-Lab environmental chamber, 47, 59

T-1 and S-2 suit use, 141

Tactical Life Support System program, 112

Boeing (McDonnell Douglas) F-15/F-15B Eagle 

See F-15/F-15A/F-15B Eagle

Boeing B-17/B-17E/B-17F Flying Fortress 

See B-17/B-17E/B-17F Flying Fortress

Boeing B-29 bombers. See B-29 Superfortress

Boeing B-52 Stratofortress. See B-52 Stratofortress

Boeing F-13 Superfortress, 124

Boeing P2B-1S (B-29) carrier aircraft, 198, 202, 206, 209

Bohn-Meyer, Marta, 340

bomber aircraft

blackout sequence for dive bombing maneuvers, 81, 82

descent rates of, 135

nuclear mission profile, 160

sealed pressure cabins for, 42–43

shirtsleeve environments, 156, 210

Soviets, strategic bombing threat from, 146–47

strategic bombing missions, 142

See also specific aircraft

Boothby, Walter M., 46, 47, 50–51, 90, 91, 123

Boothby-Lovelace-Bulbulian (BLB) oxygen masks, 91, 

122, 429n108

boots

A/P22S-2 full-pressure suit, 263, 266, 273, 276, 277

A/P22S-6 full-pressure suit, 289, 290, 294

BABM suits, 48

colors of, 276, 277
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

481

Index: B | C

Bunker Hill

C

C-1/1A/s1AM partial-pressure suits, 167–68

 double-capstan system, 165–67 reconnaissance programs, competition between, 316
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

482

Index: C

Clark, David M.

 College of Holy Cross, company ownership share of, 

 272

 education and career of, 96

 ethics of, 362–63

 G-suit standardization, 105–6

 G-valve for bladder inflation, 97

 Henry, assistance to, 126

 Henry Suit (S-1 partial-pressure suit), testing of, 128

 Henry Suit, design of, 133

 Iberall, relationship with, 242

 Julia Greene, work with, 99, 103, 104, 126, 133

 knitting business of, 96–97

 Link-Net fabric, development of, 155, 191, 242, 

 441n118

 Mayo Clinic centrifuge, 76

 MC-3 suit, meeting about, 148–49, 153

 Omni-Environment Suit, 185

 opinions about, 96, 205, 244

 PAOS testing, 100

 partial-pressure suits and full-pressure suit, 

 descriptiveness of terms, x, 121

 patents awarded to, 96, 97, 441n118

 pressure suit development, role in, ix

 retirement of, 272

 Ruseckas as flight instructor, 133

See also David Clark Company

Clark, William G., 77, 126

Clark-Dreyer Oxygen System, 41–42

Cleveland Clinic, 71

closures. See zippers and fasteners

Coast Guard, U.S., 301

Cobham plc, 154

Code, Charles F., 76, 90–92, 99, 101, 103

College of Holy Cross, 272

Colley, Russell S.

 death of, 215

 de-icing boot development, 32–33

 education and career choice of, 32

 features of suits designed by, 45–46, 51

 helmet designs, 216

 joint designs and mobility, 44, 51, 56–57, 57

 Mark I (Model S) suit, 215, 218–20

 Mark III suit, 222

 Mark IV suit, 57, 180

 Mercury program suits, 215, 235

 NASA role of, 215

 patents awarded to, 57, 215

 Post pressure suit development, 32, 33–34, 35, 44, 

 215

 pressure suit development, role in, ix, 44, 215

 retirement of, 215

 Type 3 “Strato-Suit,” 44

 XH-5 pressure suit (tomato-worm suit), 45–46, 

 56–57, 57

Collier Trophy, 90

Collins, Harry, 305–6, 306

Collins, Ken, 312, 460n31

Colorado Air National Guard Base, Buckley Field, 273

Columbia (OV-102)

 accident and investigation, 410–11

 cockpit of, 374

 crew-escape options, modifications for, 384

 ejection seats, 374, 375, 378

 Orbital Flight Tests (OFT), 375–76, 378

 S1035 suits, 408, 410–11

Combat Crew Training Squadron, 4453rd, 274

COMBAT EDGE, 112–14, 115, 116

Combined Advanced Technology Enhanced Design 

G-Ensemble, 112–13. See also COMBAT EDGE

communications

 AIC-10 setup, 139, 228, 274

 A/P22S-2 full-pressure suit, 274

 BABM suits, 52

 CSU-4/P partial-pressure suit, 170

 Goodrich suits, 51, 69

 K-1 helmet, 138, 139

 Launch Entry Helmet, 381

 M-101 microphone, 358

 M-169 microphone, 358

 MA-2 helmets, 139

 Mark IV pressure suit, 228

 MB-5 helmets, 139

 MBU-24/P masks, 117

 microphone cutout switches, 377, 381

 Omni-Environment Suit, 186

 S901 full-pressure suit, 303, 306

 S901J Pilots Protective Assembly, 331

 S1010 Pilots Protective Assembly, 338, 338, 339

 S1030A Ejection Escape System suits, 377

 S1031 Pilots Protective Assembly, 348

 S1032 Launch Entry Suit, 386, 391, 392, 394, 395, 

395

 S1034 Pilots Protective Assembly, 353, 353, 358

 Snoopy Cap communications carrier, 386, 391, 395

compensated metabolism apparatus, 122

Compton, Karl T., 27

conditioned air supply equipment (CASE), 224, 226

consciousness

 altitude and oxygen requirements for, 21

 altitude and time of useful consciousness, 19, 22

 anti-G straining maneuvers, x, 73–74, 94, 113–14, 115
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

483

Index: C

 arterial pressure to maintain, 92

 blackout sequence for dive bombing maneuvers, 81, 82

 blood pressure and, 71, 92

 centrifugal force and, 71

 G-loads and loss of, 71–72, 80–83, 81, 92

 gravity-induced loss of consciousness (G-LOC), 

 71–72, 116

Contingency Altitude Protection Suit, 177

Convair

 reconnaissance aircraft proposal, 302

 T-1 and S-2 suit use by, 141

Convair B-36 aircraft. See B-36 bombers

Convair B-58 Hustler bombers. See B-58 Hustler bombers

Convair F-102 Delta Dagger. See F-102 Delta Dagger

Convair F-106 Delta Dart. See F-106/F-106B Delta Dart

Convair JTF-102A trainer, 267, 271

Convair RB-36 reconnaissance aircraft, 149, 149

Converse, Selden A. “Connie,” 220

convoluted and bellows joints, 45, 51, 51, 56–57, 57, 

195–96, 197, 203, 205, 210, 246

cooling systems

 liquid-cooling garments, 173–74, 408–9

 TLSS liquid-cooling system, 114

 Typhoon fighters, 114

Cooney, James P., 309

Cooper, L. Gordon, Jr., 234

Cornelius, Richard, 102, 107

Cornelius control valve, 102, 102, 107

Corona reconnaissance satellites, 314

Correale, James V., 227, 378

Cotton, Frank S., 22, 83–84, 99

Cotton, Frederick J., 91

Cotton Aerodynamic Anti-G Suit, 83–85, 99

counter-pressure clothing

 G-suits compared to, 126

 opposition to, 124

 research on and development of, 124

See also vests

Coupe d’Aviation Maritime Jacques Schneider 

(Schneider Trophy), 72

CPS (Crew Protective System), 386

Crew Altitude Protective System (CAPS), 386, 393

crew protection equipment. See pilot and crew protection 

equipment

Crew Protective System (CPS), 386

Crile, George W., 71, 81–82

Crippen, Robert L. “Crip,” 374, 375, 376

Croce-Spinelli, Joseph-Eustache, 41

Crossfield, Albert Scott

 collaborative suit-design efforts, v

 D558 program flights, 206, 209, 244

 D558 program suits, 198–99, 205–6, 205, 210, 244

 on David Clark, 96, 205, 244

 in Douglas Aircraft altitude chamber, 200

 MC-2 suit testing, 253–56, 255

 pressure suit development, role in, 262, 415n1

 Weldon, relationship with, 199

 X-2 program suit, 205

 X-3 program suit, 205

 X-15 program suits, 244–46, 258, 259, 262

 X-plane development, role in, 198

Crowley, John W., 205–6

CRU-73 regulator, 112

CRU-103/P regulator, 114

CSK-6/P22S-2 coveralls, 268

CSK-8/P22S-4 coveralls, 286

CSK-9A/P22-6 coveralls, 290

CSK-9/P22-6 coveralls, 289

CSU-1/P suit, 159

CSU-2/P partial-pressure suit, 158, 159, 162, 165–67, 

169, 171

CSU-3/P cutaway G-suit, 170

CSU-4/P partial-pressure suit

 ADC testing and use, 279–82, 281

 bladders, 169–70, 170, 172, 386

 color of, 171

 development and specifications, 162, 167, 169–73, 

170, 172

 distribution and use of, 171–72

 fabrics and materials, 170, 171

 helmets, 171

 neck ring, 170

 S822/S822-1/S822-1A suits, 170–72

 S1032 suit and, 386

 sizing of, 171

 underwear, 282

 wrist hose, 456n107

 zippers, 171

CSU-5/P partial-pressure suit, 172–73, 279–82, 281

CSU-12/P G-suits, 109

CSU-13A/P G-suits, 109

CSU-13B/P G-suits, 110, 112, 114, 115, 116–17, 118

CSU-13/P G-suits, 109, 110

CSU-15A/P G-suits, 109

CSU-15B/P G-suit, 114, 116

CSU-15/P G-suits, 109–10

CSU-17/P counter-pressure vest, 114

CSU-20/P cutaway G-suit, 114, 117

CSU-21/P counter-pressure vest, 114, 117

CSU-22/P G-suits, 116

CSU-23/P G-suits, 116–17. See also Advanced 

Technology Anti-G Suit (ATAGS)
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

484

Index: C | D

Curtiss C-46 Commando, 135, 153

Curtiss JN-4 Jenny biplane, 28, 80, 416n19

Curtiss P-40E Kitty-hawks, 84, 84

cutaway suits

 Berger Brothers G-3 cutaway suits, 105–6

 Clark G-3/G-3A cutaway suits, 105–8, 106

 CSU-3/P cutaway G-suit, 170

 CSU-20/P cutaway G-suit, 114, 117

CWU-4/P immersion suit, 171

CWU-27/P flyers coveralls, 118, 119

D

D-21/M-21 drone/aircraft combination, 313, 314–16, 

315, 324, 346

D558 program

 D558-1 Skystreak, 196, 198

 D558-1 Skystreak record flight, 206

 D558-2 Skyrocket, 198

 D558-2 Skyrocket record flights, 139–40, 202, 206, 

 209, 244

 escape (ejection) capsule, 245

 full-pressure suits for, v, ix, 196–210, 197, 198, 199, 

201, 202, 203, 204, 205, 244

 P2B-1S (B-29) carrier aircraft, launch from, 198, 202, 

 206, 209

 Reaction Motors XLR11 rocket engines, 209, 447n46 

 value of research, 209

Dalton’s Law of partial pressure, 21

Dana, William H. “Bill,” 174, 175, 176, 177, 275, 276, 

277, 278

Daniel, Walter F., 309

Darwin, Charles, 74

Darwin, Erasmus, 74

David Clark Company

A-12 program code name, 304, 324

air-conditioning equipment, portable, 225

Anti-G Suit (AGS) for Space Shuttle, 375–76, 378, 382

A/P22S-2 full-pressure suit. See A/P22S-2 full-pressure 

 suit

A/P22S-4 full-pressure suit. See A/P22S-4 full-pressure 

 suit

Arterial Occlusion Suit (AOS), 100, 101–2, 101, 103 

bladders, 99–100, 101, 103, 105, 105, 106, 108 

business operations and ethics, 270, 272–73, 362–63 

C-1/1A/1AM partial-pressure suits, 167–68

C-4/4A partial-pressure suit, 169

College of Holy Cross, ownership share of, 272 

contracts for G-suits, 106–7, 108–9

CSU-4/P partial-pressure suit, 169–73, 170, 172

CWU-4/P immersion suit, 171

D558 program suits, v, ix, 196–210, 197, 198, 199, 

201, 202, 203, 204, 205, 244

designation system for suits, 181, 301, 318, 362 

Dyna-Soar spacesuit contract, 270, 279

engineering activities, 363

EVA and IVA gloves, 373

facility, photos of, 269, 270

founding of, 25, 96

full-pressure suits, development of, 210, 240

G-2 suit, 95, 96, 104, 431n132

G-3/G-3A cutaway suits, 105–8, 106

G-3 G-suit, 104

Gemini spacesuit contract, 270, 279

gloves, manufacture of, 158

G-suits, 84, 86, 88, 99–105, 101, 105

helmets, 64

Henry Suit, manufacture of, 132–33, 134, 135–36, 

 144

jerkin-based ensemble, 177

leg bandage, progressively-inflating, 99

life rafts, 316

location of, 269, 270

Mark II helmet as model, 266, 454n67

Mayo Clinic, testing by, 103, 105

MB-1 partial-pressure suit, 146

MC-1 suit, development of, 141, 144

MC-2 suit testing, 254, 453n41

MC-3/3A suits, development of, 147, 148–49, 153–54

MC-3/3A suits, manufacture of, 156, 157–58

MC-4/4A suits, 159

Mercury program suits, 233, 235

milking blood up from legs, G-suit design for, 99, 100

Model 1 G-suit, 100

Model 2 G-suit, 100

Model 5 G-suit, 100

Model 6 G-suit, 100

Model 8 Arterial Occlusion Suit (AOS), 100, 101

Model 21 G-suit, 181

Munsingwear, sale to, 272

Omni-Environment Suit. See Omni-Environment Suit

ownership of and employee-ownership heritage, vii, 

 96, 272–73, 362–63

pressure suit development and manufacturing, ix, 109, 

 273, 362–63

Progressive Arterial Occlusion Suits (PAOS), 99–100, 

117, 118, 119

Prototype High Altitude Flying Outfit (PHAFO) suits, 

 296–99, 297, 298

quality of suits produced by, 270

RAF get-me-down suit, 175

Retrograde Inflation Anti-G Suit (RIAGS), 117, 

 118–19, 118, 119
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

485

Index: D

 S-100 suit. See S-100 partial-pressure suit

 S612 partial-pressure suit gloves, 160

 S787 prototype suit, 159

 S802 prototype suit, 159

 S901 suit. See S901 suit entries

 S970 full-pressure suit, 306, 310, 311, 328

 S1010 suit. See S1010 Pilots Protective Assembly (PPA)

 S1030 suit. See S1030 Pilots Protective Assembly (PPA)

 S1031 suit. See S1031 Pilots Protective Assembly (PPA)

 S1031C suit, 334, 349, 350, 351, 354

 S1032 suit. See S1032 Launch Entry Suit (LES)

 S1034 suit. See S1034 Pilots Protective Assembly (PPA)

 S1035 suit. See S1035 Advanced Crew Escape Suit 

 (ACES)

 Sears, Roebuck, and Co., manufacturing for, 107, 269

 security inspection of, 148

 sizing of flying suits, 104, 136, 156, 158, 167, 168, 

 268–69, 360

 Straightaway garment, 96–97, 98–99

 suit controllers, 217

 T-1 suits, manufacture of, 136, 137–38, 439n70

 undergarment manufacturing, 107

 valve immune to variance in source pressure, 99, 101–2

 valve modification for turbojet engines, 107

 X-15 program suits, 244–62

 XMC-2-DC suits, 243, 244, 246–53, 248, 249

 Z-1 suit, 103–4

 Z-2 suit, 104–5, 105

 Z-3 (G-4/G-4A) suits, 107–8, 109, 439n70

See also Clark, David M.

Davis, Jefferson C., 293

Davis, Robert H., 26–27, 28, 415n10

Davis-Monthan Air Force Base, 265

Dawbarn, Waring L. “Pete,” 56

DC-8 aircraft, 357

decompression

 cabin decompression, v

 flameouts and protection from slow decompression, 

 121

 physiological effects of rapid decompression, 22–23

decompression, explosive

 A/P22S-2 suit testing, 267

 CSU-4/P suit testing, 171

 NACEL research, 217

 Omni-Environment Suit testing, 202, 204

 pressurized cockpits and, 377–78

 protection against, 121

 research on, 43

 sources of, 121

 TLSS testing and survival of, 112

decompression sickness (aviator bends), xi, 21, 22, 23, 26, 

132, 141

Dent, Frederick R., Jr., 205

Descartes, René, 16

Détré, Georges, 37, 419n63

Diamond Alkali Company, 462n53

Diamond Shamrock Corp., 462n53

Diehl, John A., 30

diluter demand oxygen system, 43, 61, 62, 429n108

Diringshofen, Heinz von, 87

Discovery (OV-103), 384

Dive Bomber, 81, 427n50

diving suits and helmets, ix, 25, 26–27, 416n11

DN-500-I portable oxygen kit, 310

DN-500-U portable vent kit, 310

Dobrovolskiy, Georgiy Ivanovich, 371

Doelter, Dr., 443n161

Dominion Textiles, Ltd., 86

donning and doffing suits

 A/P22S-2 full-pressure suit, 268, 271, 272, 278–79, 

 280, 283

 assistance with, 33, 57, 199, 202, 209, 225

 CSU-4/P partial-pressure suit, 170, 171

 CSU-5/P partial-pressure suit, 173

 dressing rooms/vans, 225, 226, 227

 glove design and, 180, 217

 helmet designs and, 33, 46, 173, 184, 191

 loose-fitting garments, 165

 PHAFO suit, 296–97, 299

 S1010 Pilots Protective Assembly, 336–37

 S1031 Pilots Protective Assembly, 346–47

 time needed for, 57, 171, 187, 199, 268, 271

 zippers and, 50, 54, 87, 94, 130, 133, 155, 180, 186, 

191, 205, 207

Doolittle, Jimmy, 30, 80

Douglas A-24/SDB-3A Dauntless, 103

Douglas Aircraft

 altitude chamber and suit testing, 199, 200, 201–2, 

 204, 211

 T-1 and S-2 suit use by, 141

Douglas B/RB-66 Destroyer, 149, 156

Douglas D558 program. See D558 program

Douglas F3D Skynight, 215

Douglas F4D (F-6) Skyray, 230

Douglas X-3 aircraft, 205

Douglas XF4D Skyray, 199, 200, 201–2, 204, 211

Dräger pressure suits, 37–39, 38, 39

Dräger-Werke, AG, 37–39

Dreamland, 460n24. See also Groom Lake

Drinker, Cecil K., 75, 81

Drinker, Philip, 75

drinking and feeding system, vi, 319, 334, 340, 341, 358
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

486

Index: D | E

drones Durney, George, 369

E

EAGLE (Enhanced Anti-G Lower Ensemble), 116–18

 Air Force Flight Test Center. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

487

Index: E

 from F-104/104B Starfighter, 290

 from F-106/F-106B Delta Dart, 290

 G-suit weight and concerns about, 94

 initiation of ejections and ejection seats, 157, 167–68, 

168, 192, 194, 211, 230–31

 M-21 aircraft, ejections from, 315–16, 460n31

 Mark III suits and, 223–24

 mobility of suits and ejection initiation, 167–68, 168

 oxygen and power supply to suit during, xii

 physiological effects and risks, 22

 Space Shuttle crew-escape options, 365–66, 366, 374, 

 383–84, 383, 384

 Space Shuttle ejection seats, 365, 374–75, 374, 378

 spurs for locking to ejection seat, 273

 SR-71 ejection seats, 323, 324, 374, 375, 403

 suit performance requirements, vi

 tractor rocket-extraction system, 383–84

 U-2 ejection seats, 151, 334, 403

 visors, power for heating after ejection, 269

 from WB-57F aircraft, 290

 X-15 ejection seats, 245, 258, 261, 277, 374–75

See also back kits; get-me-down (emergency) suits; 

 seat kits

elastic bodies, 241

Elkins, William, 373

Ellington Field, 286, 294, 361, 410

Emergency Intravehicular Suit (EIS), 371–74, 372, 373

emergency suits. See get-me-down (emergency) suits

Emerson (A-12) demand regulators, 123, 124

Endeavour (OV-105), 384

Enevoldson, Einer K., 176

engines

 A-12 reconnaissance aircraft (Oxcart), 312

 altitude and operation of, 142, 237

 AR2-3 rocket engines, 140

 flameout during F-104C flight, 278–79

 flameouts and protection from slow decompression, 

 121

 flameouts in U-2 aircraft, 151

 J31 (I-16) turbojets, 107

 J33 (I-40) turbojets, 107

 J47 engines, 440n89

 J57 engine flameout incident, 223

 J58 engines, 312, 314

 J65 turbojet engines, 286

 J75 engines, 312

 J79 engines, 278

 jet aircraft compared to piston-powered aircraft, 142

 manufacturers of, 362

 piston-powered aircraft, 142, 237, 301

 R-4360 engines, 141, 142, 440n89

 RJ43 ramjet, 314, 315

 rocket engines and aircraft performance, 121

 TF33 turbofan engines, 286

 turbojets and aircraft performance, 121

 XLR11 rocket engines, 209, 447n46

 XLR99 rocket engines, 244

England. See Great Britain

Engle, Joe H., 376

Enhanced Anti-G Lower Ensemble (EAGLE), 116–18

Enterprise (OV-101), 374–75

Equipment Laboratory, Wright Field, 42–43, 44

Erickson, Mervin E., 47

Ernsting, John “J.E.,” 174, 175

ER program. See Earth resource program (NASA)

escape (ejection) capsule, 156, 213, 244–45, 383

Ethernet, 413n6

Everest, Frank K. “Pete,” Jr., 133, 134, 135, 138, 274

Ewing, Donald D., 235

Excelsior, Project, 162–65, 163, 164, 269

exosphere, 20

explosive decompression. See decompression, explosive

exposure protection. See temperature and exposure 

protection

exterior covers

 A/P22S-2 full-pressure suit, 263, 267, 276, 277, 277, 

 454n69

 A/P22S-4 full-pressure suit, 284

 A/P22S-6 full-pressure suit, 290

 flammability of fabrics, 354, 464n85

 HT-1 exterior covers, 304, 306, 309

 MC-2 full-pressure suit, 260–61, 260, 261, 263

 PBI (polybenzimidazole), 354, 376, 377, 378, 464n85

 S-100 partial-pressure suit, 320, 321

 S901 full-pressure suit, 304, 306, 309

 S901H special projects suit, 310–11

 S901J Pilots Protective Assembly, 325, 326–28, 327

 S970 full-pressure suit, 311

 S1030A Ejection Escape System (EES) suits, 376, 377, 

 378

 S1030 Pilots Protective Assembly, 341

 S1031 Pilots Protective Assembly, 348

 S1032 Launch Entry Suit (LES), 385, 390, 394–95, 

 399

 S1034 Pilots Protective Assembly, 354–56, 356, 358

 S1035 Advanced Crew Escape Suit (ACES), 399

extravehicular activities (EVA)

 EIS use, 371, 372

 ISSA suit use, 370

 pressure suit requirements, 371

 spacesuits for, 365

 study of, 371
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

488

Index: E | F

Extreme Cold Weather Survival Clothing Outfits 

F

F2H Banshee, 215

 range, capabilities, and pressure suit requirements, 111, A/P22S-6 suit testing and use, 289–90, 291
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

489

Index: F

 BABM suits, 62, 68

 ballooning of suits and, 189–91, 189, 197

 Byrd Cloth, 55–56

 Cotton Aerodynamic Anti-G Suit, 84, 85

 CSU-2/P partial-pressure suit, 167

 CSU-4/P partial-pressure suit, 170, 171

 CSU-5/P partial-pressure suit, 173

 Dacron slipnet fabric, 242

 Duplan Weatherbar polyurethane-coated nylon, 267, 

 454n69

 flammability of fabrics, 354, 464n85

 Franks Flying Suit, 86

 French pressure suits, 36

 General Electric suits, 65, 68

 German Dräger pressure suits, 37

 German get-me-down suits, 39

 Goodrich suits, 44, 45, 51, 56, 69, 210–11, 215, 219

 Goodyear suits, 47, 55–56

 Gore-Tex fabric, 351–52, 393, 463n78

 Helenca knit fabric, 170, 227–28, 309

 Henry Suit (S-1 partial-pressure suit), 133

 HT-1 fabric, 310–11

 Italian pressure suits, 36

 jerkin and jerkin-based ensembles, 274

 latex rubber, 242–43

 liquid-cooling garment, 174

 Mark IV pressure suit, 227–28

 marquisette, 246–47, 250, 263, 283, 287, 306, 373–74

 MC-2 full-pressure suit, 246, 247–48, 247, 248, 250, 

251, 252, 253, 260–61

 Mercury program suits, 221

 Model 7 full-pressure suit, 180

 NACEL evaluation of, 189

 National Carbon Company suits, 50

nopcofoam, 334, 462n53

nylon fabric, 167

Omni-Environment Suit, 181, 189–91, 189, 192, 

 195, 195, 196, 197, 204, 206, 210, 446n40

open-weave net fabric, 189–91, 189, 192

polybenzimidazole (PBI), 354, 376, 377, 378, 464n85

Post pressure suit, 30, 33

Prototype High Altitude Flying Outfit suits, 296, 297, 

 299

reflective fabric for spacesuits, 259, 260–61, 261

research on human perceptions about, 242

Ridge pressure suit, 26–27

S-100 partial-pressure suit, 320

S901 full-pressure suit, 159, 306, 309

S901H special projects suit, 310–11

S901J Pilots Protective Assembly, 325–26, 328–29, 334

S1030A Ejection Escape System (EES) suits, 376, 377, 

 378

S1030 Pilots Protective Assembly, 341, 343, 352

S1031 Pilots Protective Assembly (PPA), 352

S1031 Pilots Protective Assembly, 348, 352

S1032 Launch Entry Suit (LES), 389, 390, 393, 

 394–95

S1034 Pilots Protective Assembly, 351–56, 356, 358

Spanish pressure suits, 39

suit-induced stress and fatigue and, 351

Teflon-coated yarns and fabric, 167

Terylene fabric, 274

Trilok fabric, 173, 221, 228, 263

U.S. Rubber suits, 44, 49

waffle-weave fabric, 196, 197, 204, 210

XMC-2-DC suits, 246–48, 248, 250

See also Fypro material; Link-Net fabric; Nomex fabric

face seals

 A/P22S-2 full-pressure suit, 259, 266, 268, 269, 283

 A/P22S-6/6A full-pressure suit, 290

 neck seals versus, 258–59

 S-100 partial-pressure suit, 318, 319

 S901J Pilots Protective Assembly, 331

Faget, Maxime A. “Max,” 233

FAI. See Fédération Aéronautique Internationale (FAI)

fainting in the air, 72, 73. See also consciousness

Fairchild reconnaissance aircraft, 149–50

Fairey Battle aircraft, 87

Falcon (AIM-47/GAR-9/GAR-X) missiles, 307, 308, 378

Farabi, Al-, 15

fasteners. See zippers and fasteners

Federal Air Regulation, 414n28

Federal-Mogul-Bower. See Arrowhead Products Division, 

Federal-Mogul-Bower

Fédération Aéronautique Internationale (FAI)

 Gold Medal award to Post, 29

 record-setting flights, 29, 34, 36, 41, 165, 233, 309, 

 418n59, 419n63, 419n78, 419n80, 464n93

feeding and drinking system, vi, 319, 334, 340, 341, 358

Ferwerda, Thomas J., 98

Feynman, Richard P., 382

fighter aircraft (pursuit airplanes)

 acceleration and air combat maneuvers, 113–14

 G-suits and fighter combat missions, 88

 high-altitude flights by, 45

 loss of consciousness by pilots, 72

 pilot attitude toward pressure suits, 286, 294

 supersonic aircraft, 301

See also specific aircraft

Fighter Interceptor Squadron, 325th, 279–81

fighter squadrons
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

490

Index: F

 VF-8 Ghost Cats, 94 special project suits, 316 fabrics and materials, v
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

491

Index: G

G

G-1 G-suit, 93–95, 

 pressure suit development by, 36, General Dynamics (Lockheed Martin) F-16/F-16B 

Fighting Falcon. See F-16/F-16B Fighting Falcon

General Dynamics F-111C/F-111D fighter-bombers, 

285, 457n118

General Dynamics WB-57F reconnaissance aircraft. 

See WB-57F aircraft

General Electric (GE)

 capstan-controlled leg pressure G-suits, x, 104, 115, 

 126

 fabrics and materials for suits, 65, 68

 Henry Suit, interest in producing, 132

 J31 (I-16) turbojets, 107

 J33 (I-40) turbojets, 107

 J79 engines, 278

 L-12 G-suit, 104

 M61 Vulcan 20mm cannon, 141

 Navy, pressure suit testing by, 65–66, 68

 pressure suit development by, 65, 67

 turbojet engines, 278, 440n89

General Motors, Allison Division, 140–41

Gentex Corporation

 HGU-20/P helmet, 380–81

 Launch Entry Helmet (LEH), 378–82, 379, 380, 381

 Protection, Inc., purchase of, 380

 Tactical Life Support System program, 112

Gentry, Jerauld R., 277

George Air Force Base, 380

Germany

 Air Force Institute of Aviation Medicine, 115

 CSU-4/P suit use by, 171–72

 Dräger pressure suits, 37–39, 38, 39

 get-me-down suits, 37, 39, 39

 G-suit development, x, 87, 88, 89

 Libelle G-Multiplus G-suit, 114–16
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

492

Index: G

 A/P22S-4 full-pressure suit, 284, 286

 A/P22S-6 full-pressure suit, 289, 290, 294

 Apollo program suits, 296

 BABM suits, 48

 disconnect incident and problems, 278–79, 284

 early designs, 27

 Emergency Intravehicular Suit (EIS), 371–72, 373–74

 EVA and IVA gloves, 373–74

 General Electric suits, 67

 German pressure suits, 38

 Goodrich suits, 47, 217

 HAK-3/P22S-2 gloves, 268, 269

 HAK-10/P22S-4 gloves, 286, 289, 290

 Henry Suit (S-1 partial-pressure suit), 128, 129, 132

 HT-1 fabric, 159

 Intravehicular Space Suit Assembly (ISSA), 368, 369

 Link-Net fabric use, 272

 Mark IV pressure suit, 227, 228

 MC-1 Featherweight suit, 144–45

 MC-2 full-pressure suit, 245, 246, 250, 250, 252

 MC-3/3A partial-pressure suit, 158, 160, 165

 MC-4/4A partial-pressure suit, 158, 160

 MG-1 gloves, 296

 Model 7 full-pressure suit, 180, 180

 Omni-Environment Suit, 182, 183–84, 185, 186, 

 187, 191, 203, 206, 209

 protection provided by, xi

 Prototype High Altitude Flying Outfit suits, 296

 S-100 partial-pressure suit, 321

 S612 partial-pressure suit gloves, 160

 S901 full-pressure suit, 309

 S901J Pilots Protective Assembly, 287, 327, 328–29

 S1010 Pilots Protective Assembly, 337, 337

 S1032 Launch Entry Suit, 386, 401

 S1034 Pilots Protective Assembly, 353–54, 401

 S1035 Advanced Crew Escape Suit, 401

 U.S. Rubber suits, 45, 47

 XMC-2-DC suits, 250, 252, 452n38

 XMC-2-ILC suits, 245, 246

goggles. See visors and goggles

Good, Michael, 404

Goodell, John Charles, 154

Goodlin, Chalmers H. “Slick,” 133

Goodrich. See B.F. Goodrich Company

Goodyear Tire & Rubber

 advances in suit design and development, 68

 Army, pressure suit development for, 43, 44, 47, 

 52–55, 60, 68, 420n102

 cost of pressure suits, 47

 fabrics and materials for suits, 47, 55–56

 helmets, 53, 54, 54

 MX-117 project suits, 52

 Navy, pressure suit testing by, 54–55, 63–65

 pressure suit development, coordination of research 

 for, 52–53

 Type 9/9A pressure suit, 44, 47, 53–54, 53, 420n102

 XH-3/XH-3A/XH-3B pressure suit, 44, 54–56, 54, 

 60, 66, 68

 XH-9 pressure suit, 44

 zipper, development of airtight, 54

Gore, Robert W., 463n78

Gore, Wilbert L., 463n78

Gore-Tex fabric, 351–52, 393, 463n78

Gorman, William Augustus, 416n11

Graf Zeppelin (Germany), 29

Grand Forks Air Force Base, 293, 293, 294

Graves, Jimmy B., 173

gravity, relationship to centrifugal force, 74

gravity-induced loss of consciousness (G-LOC), 71–72, 

116

Gray, Roy C., 224

Great Britain

 Air Commission, request for pressure suit information 

 by, 45

 Air Ministry, interest in pressure suits by, 27, 40

 fighter aircraft, high-altitude flights by, 45

 Grenfell Cloth, 55

 MacRobertson Race, 29, 33, 417n28, 418n43

 pressure suit development by, 26–27, 27, 36, 40–41, 

41, 415–16nn10–11 

See also Royal Air Force (RAF)

green apple emergency-oxygen activator, 383, 392, 397, 

408

Greene, Julia, 99, 103, 104, 126, 128, 132, 133

Greer, Calvin E., 378

Greig, D’Arcy, 87

Grenfell Cloth, 55

Gressly, Donald W., 55, 60, 61–62, 63, 64, 65

Griffith, John H., 131

Grissom, Virgil I., 234

Groom Lake

 A-12 aircraft testing, 301, 311, 316, 323, 460n24

 location of, 150, 460n24

 M-21 test flight, 324

 names for, 460n24

 operation OVERFLIGHT, 153–54

 U-2 aircraft testing and maintenance, 150, 155, 156, 

 265

 YF-12A/AF-12 testing, 308

Gross, Mervin E., 89
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

493

Index: G

Grumman CSU-20/P cutaway G-suit, 114, 117 Model 6 G-suit, 100
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

494

Index: G | H

GUS (garment, upper stratosphere) Mark III suit, 222, 

226–27

G-valves, 97, 111–12, 113, 176

G-Whiz aircraft, 103

H

Haderlie, Kermit L., 278–79

HAFO (High Altitude Flying Outfit) program, 293–99

Haise, Fred W., Jr., 376

HAK-3/P22S-2 gloves, 268, 269

HAK-10/P22S-4 gloves, 286, 289, 290

Haldane, John Burdon Sanderson “Jack,” 26

Haldane, John Scott, 25, 26–27, 28, 30, 415n8

Haldane-Davis stratosphere flying suit, 26–27, 27, 28, 

30, 40–41, 41

Hall, F. Gregory, 77

Hall, Florence C. “F.C.,” 28, 29

Hallenback, George A., 105

Ham, Ken, 404

Hamilton Standard Division, United Aircraft 

Corporation, 371, 372–73

hands, swelling of, 128

Harmon Trophy, 29, 233

Harry G. Armstrong Aerospace Medical Laboratory, 

117–18, 119, 425n24

Hartsfield, Henry W. “Hank,” 376

Harvard University

 aeromedical and physiological research, 42, 43, 81

 altitude chambers, 75

 sock development by, 128

Hawker Hurricane, 84, 87

Hazelhurst Field, 31, 41–42

Head, Henry, 72, 73

Heald Machine Company, 99, 101

Heim, J. William “Bill,” 43, 74, 75, 81

Helenca knit fabric, 170, 227–28, 309

helium, 18

helmets

 anti-suffocation feature, xii, 267, 299, 310, 319, 334, 

 361, 395

 AOH-1 (Aviator Oxygen Helmet), 378

 A/P22S-2 full-pressure suit, 263, 266, 267, 268, 269, 

 272, 274

 A/P22S-4 full-pressure suit, 284, 286

 A/P22S-6/6A full-pressure suit, 289, 290, 291, 

 317–19, 318, 319, 361

 BABM suits, 46, 47, 49–50, 49, 52, 58, 62, 64, 65

 Bill Jack helmets, 157, 263

 British pressure suits, 40

 clamshell construction, 349, 378–82, 379, 380, 381

 Colley-designed, 216

 CSU-4/P partial-pressure suit, 171

 David Clark Company, 64

 drinking and feeding system, vi, 319, 334, 340, 341, 

 358

 early designs, 25

 faceplates and visual field, 268

 full-pressure helmets, development of, vi

 General Electric suits, 67, 68

 German get-me-down suits, 39, 39, 419n70

 German pressure suits, 37, 38

 Goodrich suits, 51, 210–11, 212, 214, 217–19, 

 222–23, 235

 Goodyear suits, 53, 54, 54

 handmade helmets, 360

 Henry Suit (S-1 partial-pressure suit), 129, 130, 130, 

 132, 133, 134

 HGK-12/P22S-2 helmets, 268, 269

HGK-19/P22S-4 helmets, 286, 289, 290

HGU-8/P helmet, 170, 171

HGU-15/P helmet, 378, 380

HGU-20/P helmet, 380–81

HGU-55/P helmet, 113, 114

HGU-68/P helmet, 114, 117

holddown system, 245, 246, 253, 260, 263, 266, 284, 

 291, 291, 358

Intravehicular Space Suit Assembly (ISSA), 368, 368

K-1 helmet, 134, 137, 138–39, 138, 139, 141, 144, 

 145, 161

Launch Entry Helmet (LEH), 378–82, 379, 380, 381, 

 397, 398

liner, nopcofoam, 334, 462n53

Link-Net fabric for U-2 pilot helmets, v, 155

MA-1 helmets, 139

MA-2 helmets, 139, 154, 155, 157, 158, 159, 171, 

 317

MA-3 helmets, 157, 171, 261–62

Mark II suit, 218, 266, 454n67

Mark IV pressure suit, 216, 227, 228

MB-5 helmets, 139, 144, 145, 157

MC-1 Featherweight suit, 139, 145

MC-2 full-pressure suit, 246, 257, 260, 261–62, 263

MC-3/3A partial-pressure suit, 139, 155, 157

Mercury program suits, 233, 235

Model 7 full-pressure suit, 180, 181

neck seals, 258–59, 260, 395–96

Omni-Environment Suit, 181, 182, 184, 187–89, 

187, 190, 191–92, 191, 196, 197, 202, 203, 204, 

 206, 208, 214, 215

pink, 382

plexiglass helmets, 39, 39, 44–45, 51, 51, 54, 54, 184, 

203, 204, 419n70
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

495

Index: H | I

 Post design, 30, 31, 32, 33, 35

 protection provided by, xi

 Prototype High Altitude Flying Outfit (PHAFO) suits, 

 296

 rubber bladder for under, 138

 S-2 partial-pressure suit, 138–39

 S-100 partial-pressure suit, 317–19, 318, 319, 321

 S901 full-pressure suit, 303, 309, 310

 S901J Pilots Protective Assembly, 287, 328, 331, 334, 

 341

 S970 full-pressure suit, 328

 S1010D helmet, 386

 S1010 Pilots Protective Assembly, 337, 337, 338–39, 

339

 S1030L/S1031L helmets, 349, 352–53

 S1030 Pilots Protective Assembly, 334, 339, 339, 

 340–41, 342, 349

 S1031 Pilots Protective Assembly, 339, 348, 348, 349

 S1032 Launch Entry Suit, 349, 382, 386, 395, 398

 S1034E helmet, 359, 360, 361, 363

 S1034 Pilots Protective Assembly, 353, 353, 358, 361

 S1035 Advanced Crew Escape Suit, 349

 Spanish pressure suits, 39

 surplus, ads for and sale of, 161, 161

 T-1 partial-pressure suits, 137, 138–39, 138

 Type 3 “Strato-Suit,” 44

 U.S. Rubber suits, 44–45

 XH-5 pressure suit, 60

 XMC-2-ILC suits, 245

See also face seals; neck rings; visors and goggles

Henry, James Paget “Jim”

 capstan-controlled pressure, interest in, 104, 126

 Clark’s assistance to, 126

 education and career of, 125

 Julia Greene, work with, 104, 126

 patents awarded to, 134, 439n59

 pressure breathing research, 126

 USC human centrifuge, building of and research with, 

 77, 126

 X-1 rocket plane, get-me-down suit for, 126

 Z-1 suit, testing of, 103

Henry Suit (S-1 partial-pressure suit), 125–30, 129, 130, 

132–34, 134, 135–36, 144, 179, 237, 437n32

Herrera Linares, Don Emilio, 39–40

HGK-12/P22S-2 helmets, 268, 269

HGK-19/P22S-4 helmets, 286, 289, 290

HGU-8/P helmet, 170, 171

HGU-15/P helmet, 378, 380

HGU-20/P helmet, 380–81

HGU-55/P helmet, 113, 114

HGU-68/P helmet, 114, 117

H.I. Garment Company, 136

high-altitude flight

advances in suit development, vi

 balloon flights. See balloon flights

 breathing process and, x, 21–22

 British fighter aircraft, 45

 clothing for, ix–xii

 full-pressure suits for, v

 partial-pressure suits for, v

physiological risks associated with, xi, 20, 21, 22–23

 pilot stress from, 43

 Post flights, 29, 34–35, 36

 record-setting flights. See record-setting flights

 TAC flights, 286

High Altitude Flying Outfit (HAFO) program, 293–99

High Altitude Protective Outfit, 386

Hilsz, Marie-Louise “Maryse,” 37, 419n63

HL-10 lifting body, 275, 276

Hoag, Peter C., 277

Hoagland, Hudson, 97–98

Holloman Air Force Base (AFB)

 Libelle G-Multiplus G-suit testing, 115

 Stargazer, Project, 165, 166

Holmes, Bradford, 124

Home Base, 460n24. See also Groom Lake

Homey Airport, 460n24. See also Groom Lake

Hood Rubber Company, 128

Hooke, Robert, 17

Hook Maneuver, 113

Hoover, Robert A., 133

Horton, Vic, 331

HT-1 fabric, 304, 306, 309, 310–11

Hucks, William R., 30, 417n35

Hughes AIM-47 (GAR-9/GAR-X) Falcon missiles, 307, 

308, 378

Hughes AN/ASG-18 fire control system, 308

Hughes XF-11 aircraft, 149

human factors, pressure suits and, v

human space flight, engineering and management culture 

surrounding, 382–83

Hurricane aircraft, 84, 87

Hyde Athletic Shoe Company Model Z100 flying boots, 

452n38

hydrogen, 18

hypoxia, xi, 22–23, 41, 43

hypoxic environment, acclimatization to, 21

I

I-16 (J31) turbojets, 107

I-40 (J33) turbojets, 107

Iberall, Arthur S., 187, 195, 198, 241–43
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

496

Index: I | J 

Idealist project, 150. See also U-2 spy plane “Dragon 

Lady”

ILC Dover. See International Latex Corporation 

(ILC/ILC Dover)

IM-99 BOMARC surface-to-air missile, 314

impact-strike protection, xii

industry and industrial base

 aircraft and engine manufacturers, 362

 pressure suit manufacturers, 362–63

 shrinking industrial base, 362–63

 skills for suit production, 363

 sole source contracting, 108–9

 vendors, vanishing, 363, 463n81

Ingersoll Rand, 154

Institute of Aviation Medicine, Royal Air Force, 174, 175

Institute of Aviation Medicine/No. 1 Clinical 

Investigation Unit, 86

insulin, 76, 86, 426n30, 427n67

interceptor aircraft

 A/P22S-2 suit use, 271, 272, 273–74

 range, capabilities, and pressure suit requirements, 146, 

 147, 147, 239–40, 239, 307

 S901F suit use, 308

See also specific aircraft

International Latex Corporation (ILC/ILC Dover)

 Apollo program suits, 232, 246, 296, 362, 367, 369, 

 371, 372

 Briefcase Suit, 369, 369, 370

 Emergency Intravehicular Suit, 371–72, 372, 373, 373

 EVA and IVA gloves, 373

 full-pressure suits, development of, 362, 367

 Intravehicular Space Suit Assembly, 369–70, 369, 370, 

 371

IVA suit development, 371

 MA-2 helmets, 139, 154, 155, 157, 158, 159, 168, 171

 Mercury program suits, 232, 233, 235

 Prototype High Altitude Flying Outfit, 296, 299

 SPD-117 full-pressure suit, 232, 235

 XMC-2-ILC suits, 232, 243, 244, 245, 246, 248, 

 252–53

International Space Station (ISS) program, 410

intravehicular activity (IVA)

 Emergency Intravehicular Suit, 371–74, 372, 373

 Intravehicular Space Suit Assembly, 366–70, 368, 369, 

 370

 study of, 371

Intravehicular Space Suit Assembly (ISSA)

 Briefcase Suit, 369, 369, 370

 gloves, 368, 369

 helmets, 368, 368

 ILC suit, 369–70, 369, 370, 371

 joint designs, 367, 369

 Space Age Control suit, 366–69, 368

 weight of, 368, 370

isothermal layer, 19

Israeli Defense Forces, 175, 288, 289

ISS (International Space Station) program, 410

Italy, 36, 89

J

J-5 Whirlwind engine, 28

J31 (I-16) turbojets, 107

J33 (I-40) turbojets, 107

J47 engines, 440n89

J58 engines, 312, 314

J65 turbojet engines, 286

J75 engines, 312

J79 engines, 278

Jacobs, Harold J. “Jake,” 133

James, A.A., 86

Japan, 89

Japanese Self-Defense Air Force, 172

Jarvis, Gregory B., 382

JAS-39 Gripen, 115–16

Jedeka, Lloyd W., 127

Jenson, Theodore A., 286–87

jerkin and jerkin-based ensembles, 174–77, 177, 265, 274

Jester, Richard, 224

jet aircraft compared to piston-powered aircraft, 142

jetstream, 29

JF-104A aircraft, 229

J.H. Emerson Company, 123

JN-4 Jenny biplane, 28, 80, 416n19

John B. Pierce Laboratory, 122

Johnson, Clarence L. “Kelly”

 A-12 aircraft program, 302, 303, 305, 311

 AF-12/YF12 interceptor program, 308, 309

 Angel, 150, 459n1. 

See also U-2 spy plane “Dragon Lady”

 Archangel, 302, 459n1. 

See also A-12 reconnaissance aircraft (Oxcart)

 Blackbird reconnaissance aircraft, development of, 127, 

 322

 F-104 fighter, development of, 127

 M-21/D-21 aircraft/drone combination, 314

 P-80 Shooting Star, development of, 127, 127

sense of humor of, 302

 U-2 spy plane, development of, 127, 150, 334

Winnie Mae modifications, 34
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

497

Index: J | K | L

Johnson, Louis A., 28

Johnson, Lyndon B., 322–23

Johnson, Richard S., 235

Johnson Space Center (JSC)/Manned Spacecraft Center 

(MSC)

 anti-G suit for Space Shuttle OFT flights, 375

 ISSA suit, 366–67, 369, 370

 pressure suit requirements study, 366–67

 S1030 and S1030A suits, hardware sharing between, 

 378

 Space Shuttle crew-escape options, development of, 384

 Space Shuttle simulator, 379, 385, 397

joint designs

 ball-bearing joints, 37, 39, 56, 192–94, 193, 196, 197, 

 205, 206, 207, 209–10

 bellows and convoluted joints, 45, 51, 51, 56–57, 57, 

 195–96, 197, 203, 205, 210, 246

 German suits, 37

 Goodrich suits, 215

 ISSA, 367, 369

 Link-Net fabric and, 248, 250

 MC-2 full-pressure suit, 246

 metal joints, 44

 net-covered joints, 241–42

 Omni-Environment Suit, 192–96, 193, 194, 195, 

197, 198, 198, 199, 203, 205, 209–10, 214

 single-axis joints, 174

 thrust bearing joints, 174, 192–94, 193

 tomato-worm suit, 56–57, 57, 195

Joint Services Pressure Breathing Conference, 124

Jones, W.L., 227

JSC (Johnson Space Center). See Johnson Space Center 

(JSC)/Manned Spacecraft Center (MSC)

JTF-102A trainer, 267, 271

K

K-1 helmet, 134, 137, 138–39, 138, 139, 141, 144, 

145, 161

K-2B flight overalls, 171

Kadena Air Force Base, 316

Kearby, John G.

 counter-pressure vests, development of, 123

 death of, 68, 179

 full-pressure suits, development of, 122

 pressure breathing research, 122

 pressure suit development, 69, 123

 pressure suit testing, 52, 53, 54, 55, 68

 as project officer for pressure suit contracts, 44, 68, 

 122

Kedlock, Project, 308

Kelly Air Force Base, 290

Kelly One-Piece (K.O.P.), 85–86

Kelly’s Angel, 150. See also U-2 spy plane “Dragon Lady”

Kennedy, John F., 233

Kennedy Space Center, Launch Complex 39B, 382

Kenneway, Al, 369

Kenny, Edward W., 273

Kincheloe, Iven C., Jr., 259

King, Alice, 130, 133

Kirtland Air Force Base, 264, 286

Kittinger, Joseph W., Jr., 161, 162–65, 163, 164, 166, 

269

Knapp, Budd F., 271–72

Knight, William J. “Pete,” 278

Knipfer, Charles, 26

Knutson, Martin A. “Marty,” 154–55

Kops Brothers, 136

Krupp, Carroll P., 57

krypton, 18

L

L-12 G-suit, 104

lace-adjustment features

 Berger Brothers suits, 92, 93, 94

 capstan-controlled leg pressure G-suits, x, 104, 126

 Clark cutaway suits, 105

 CSU-2/P partial-pressure suit, 167

 CSU-4/P partial-pressure suit, 170

 CSU-12/P G-suits, 109

 CSU-13B/P G-suits, 105

 CSU-13/P G-suits, 109

 CSU-15/P G-suits, 109

 CSU-20/P cutaway G-suit, 114

 CSU-21/P counter-pressure vest, 114

 effectiveness of, 126

 F-16/PBG G-suits, 110

 Franks Flying Suit, 87

 G-3A suits, 106

 Henry Suit (S-1 partial-pressure suit), 127, 130, 133

 MC-3/3A partial-pressure suit, 155

 MC-4/4A partial-pressure suit, 159

 Omni-Environment Suit, 185, 186, 187

 Retrograde Inflation Anti-G Suit, 118

 S-100 partial-pressure suit, 319

 S901 full-pressure suit, 309

 S901J Pilots Protective Assembly, 325–26

 S1030 Pilots Protective Assembly, 343

 U.S. Rubber suits, 44

LaHaye, James D., 223

Laine, Mae, 28

Lambert, Edward H., 100, 114

Lamport, Harold, 53, 104, 115, 126

Lancaster Iron Works, 42

Land, Edwin M., 302
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

498

Index: L

Langley Research Center, 233, 235 Life Support Systems AG, 115 X-15 suit, v
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

499

Index: L | M

Lockheed P-38 (F-5) Lightning, 95, 124, 149

M

M-21/D-21 aircraft/drone combination, 

M-101 microphone, 358 Space Shuttle crew-escape options, development of, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

500

Index: M

 visors, 228, 230

 weight of, 230

 zippers, 180, 216, 228

Markum, Ed, 306, 306

Mark V pressure suit, 233

Marquardt RJ43 ramjet, 314, 315

marquisette, 246–47, 250, 263, 283, 287, 306, 373–74

Marshall, Gerald Struan, 40

Marshall Space Flight Center, 227, 227

Martin B-57/RB-57 Canberra, 149, 155, 156, 171, 286. 

See also WB-57F aircraft

Marvin, Lee, 227

masks. See oxygen masks, supply, and systems; pressurebreathing masks

Matthews, George, 369

Mattingly, Thomas K. “Ken,” 376

Maxim, Hiram Stevens, 71

Maxus Energy Corp, 462n53

Mayo, Charles Horace, 91

Mayo, William James, 91

Mayo, William Worrall, 91

Mayo Clinic

 Aero Medical Unit, 90–91, 437n20

 altitude chamber testing, 51–52, 55, 181

 anti-G straining maneuvers, 73–74, 113

 BABM suits, 46–47, 48, 51–52, 55, 59, 179. 

See also BABM suits

 Berger Brothers suits, testing of, 92–93, 94, 103, 105

 counter-pressure vests, development of, 123

 David Clark suits, testing of, 103, 105

 founding of, 91

 Franks Flying Suit, testing of, 88

 G-2 suit development, 95

 General Electric G-suit, testing of, 126

 G-suit research at Wright Field, 43 Crossfield role in development of, importance of, 262

 custom fitted suits for pilots, 259–60, 260

 delivery schedule for suits, 258, 453n54

 depot for maintenance, testing, and logistical support, 

 264

 development and specifications, 232, 242, 247, 253

 distribution and use of, 279

 exterior cover, 260–61, 260, 261, 263

 fabrics and materials, 246, 247–48, 247, 248, 250, 

251, 252, 253, 260–61

 face seals versus neck seals, 258–59, 260

 funding for, 258, 259

 gloves, 250

 gloves and mittens, 245, 246, 250, 250, 252

 helmets, 246, 257, 260, 261–62, 263

 joint designs, 246

 Link-Net fabric use, 159, 247–48, 247, 250–52, 250, 

 253, 257, 260, 263

 nitrogen for pressurization, 261–62, 453n54

 number of X-15 flights with, 261, 262

 oxygen masks, systems, and supply, 256, 258–59, 259, 

 261–62, 453n54

 pilot attitudes toward, 262

 restraint layer, 247, 248, 250, 253

 rocket-sled evaluations, 257

 S794-1 suit, 253

 S794-2 suit, 253

 S794-3C suit, 253–56, 254, 453n41

 S794-4 suit, 256, 257

 S794-5 suit, 256–57

 S794-6 suit, 257–58

 S794-7 suit, 258

 seat kits, 258

 suit controllers, 256

 human centrifuge, 76–77, 77, 88, 91–92, 95, 99, 100, 

 126, 181

 Model 7 full-pressure suit testing, 181

 oximeter, development of, 122

 oxygen mask development, 91

 Progressive Arterial Occlusion Suits, testing of, 100, 

 119

 Straightaway garment, testing of, 98–99

 T-1 suits, testing of, 139

 tire for centrifuge, 99

Mayo Medical Museum, 91

Mayo Properties Association, 91

MB-1 partial-pressure suit, 146–47

MB-2 partial-pressure suit, 147

MB-5 helmets, 139, 144, 145, 157

MBU-20/P oxygen masks, 114, 117

MBU-24/P oxygen masks, 114, 117

MC-1 Featherweight suit

 bladders, 144, 145–46, 154, 155

 contracts for, cancellation of, 156–57

 development and specifications, 141, 144–46, 144, 

 147–48, 239

 distribution and use of, 156

 gloves, 144–45

helmets, 139, 145

 MC-3/3A development, basis for, 154

 modifications to, 154

 replacement of, 155

 surplus suits, ads for and sale of, 161

MC-2 full-pressure suit

 back kits, 256, 258, 259, 262

 bids for suits designs, 243–44

 biomedical data collection, 260
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

501

Index: M

 suits based on, 262

 testing of, 252, 253–57, 255, 257, 267, 453n41

 underwear, 253

 ventilation, 256

 ventilation garments, 260

 visors, 262

 weight of, 250, 256

 X-15 program use, 229, 243–62, 278

 XMC-2-DC boots, 252, 452n38

 XMC-2-DC suit fabrics and materials, 246–48, 248, 

 250–52

 XMC-2-DC suit gloves, 250, 252, 452n38

 XMC-2-DC suits, 243, 244, 246–53

 XMC-2-DC suit testing, 248, 249, 252–53

 XMC-2-ILC suits, 232, 243, 244, 245, 246, 248, 

 252–53

MC-3/3A partial-pressure suit

 ADC use, 156, 240

 A/P22S-2 suit compared to, 271–72

 bladders, 155, 155

 capstans, 155, 155

 comfort of, 153, 162, 168–69

 configurations of, 157–58

 contracts for, 156

 custom fitting of, 149, 153–54

 development and specifications, 144, 145, 147–48, 

 153–55, 155, 157–59, 157, 160, 167, 239

 ejection initiation, modifications for, 168

 Excelsior project and MC-3A suit, 162–65, 163, 164

 gloves, 158, 160, 165

 helmets, 139, 155, 157

 lace-adjustment features, 155

 MANHIGH project and MC-3A suits, 161–62, 165

 as mission-completion suits, 156

 S-100 design and, 317

 S616 suits, 157

 S621/S621L/S621R/S621LM/S621AR suits, 157

 S687 suits, 157

 S799 suits, 157, 158

 S836 suits, 158

 sizing of, 149, 156

 Stargazer project and MC-3A suit, 165, 166

 success of design, 161

 surplus suits, ads for and sale of, 161

 testing of, 155

 underwear, 162

 zippers, 155, 159

MC-4/4A partial-pressure suit

 ADC use, 156

 development and specifications, 157–59, 158, 159

 distribution and use of, 160

 gloves, 160

 Link-Net fabric, 159

 mobility, 168–69

 S805 suits, 157

 S814 suits, 158

 sizing of, 158, 167

McAuliffe, Sharon Christa, 382

McClure, Clifton M., 161, 162

McDill Air Force Base, 274

McDonnell Aircraft Company

 altitude chamber, 225

 Mercury program capsule, 233

McDonnell Douglas (Boeing) F-15/F-15B Eagle. 

See F-15/F-15A/F-15B Eagle

McDonnell Douglas Atlantis Warrior program, 114

McDonnell Douglas CF-18 Hornet, 112

McDonnell F2H Banshee, 215

McDonnell F-4/F-4A/F-4B/RF-4C (F4H/F4H-1) 

Phantom II, 230, 274, 289, 291, 295, 457n118

McDonnell F-101 Voodoo, 147, 156, 239, 240, 312

McEachern, James D. “J.D.,” 136

McGowan, Richard J. “Dick,” Jr., 204, 224

McGuire, Terence F., 154

McKay, John B. “Jack,” 139, 250, 259, 259

McLean, Harry, 86

McMurtry, Thomas C., 331

McNair, Ronald E., 382

Meakin, L.W., 60–62, 65

mechanical effects, 23

Medical Research Board, 41

Medical Research Laboratory, Army Signal Corps, 31, 

41–42. See also School of Aviation Medicine (Army)

Meek, George A., 76, 87

Meidenbauer, Clifford, 154

Meidenbauer, Philip Edward “Ed,” Jr., 154, 216

Melvin, Jewel M., 174, 176, 286

mercury, 16–17, 20, 21

mercury displacement pump, 18

mercury piston pump, 18

Mercury program

 animal research program, 125

 astronaut screening for, 153

 capsule for, 233, 365

 centrifuge for pilot training, 78, 79, 80

 Colley-designed suit for, 215

 fabrics and materials for suits, 221

 Goodrich suits, 233, 234, 235

 helmets, 233, 235

 ILC suit, 232, 233

 Mercury Seven, 234

 quick fix suits, 234, 235
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

502

Index: M

 shirtsleeve environments, 235

 spacesuit for, Mark III suit as basis, 224

 spacesuit for, Mark IV modification for, 231, 234, 235

Mertz, H.E., 35

mesopause, 20

mesosphere, 20

Messerschmitt Me 163 aircraft, 146

methane, 18

MG-1 gloves, 296

microphone cutout switches, 377, 381

MiG-25 aircraft, 293

Military Airlift Command (MAC), 286–87, 289

Military Assistance Program, 161

Milliken, Glenn, 122

Milliken, William F., Jr., 52

Mineola Chamber, 31, 41, 42

Mine Safety Appliances Company, 123–24

Minneapolis-Honeywell Regulator Company, 52

Minnesota Mining and Manufacturing Company (3M) 

fabric, 210

Minute Maid Park, 404–5

mission-completion suits, 156, 169, 192, 240

Miss Silver Town, 33

Mitchel, John Purroy, 42

Mitchel Field

 Medical Research Laboratory/School of Aviation 

 Medicine, 42

 naming of, 42

 training at, 42

Mitsubishi A6M Zero, 85, 94

mittens. See gloves and mittens

mobility

 BABM suits, 52, 55, 56, 58, 62

 challenge of suit design for, xi, 69

 ejection initiation and mobility of suits, 167–68, 168

 fabric to increase, 189–91, 189

 face seals versus neck seals, 258–59

 full-pressure suits, xi, 30, 31, 36, 37, 237, 267

 General Electric suits, 65–66, 67

 German suits, 37, 39

 Goodrich suits, 46, 47, 51, 54, 56, 56, 61–62

 Goodyear suits, 54, 54, 55, 60, 64–65

 joint designs and. See joint designs

 lines of nonextension, 195, 198

 Mark III suit, 223

 Omni-Environment Suit, 182, 184, 187, 187, 

 189–91, 189, 192–96, 193, 194, 195, 197, 199, 

 204, 209, 214–15

 partial-pressure suits, xi, 167–68, 168, 237

 requirements for, 44, 66

 S1032 Launch Entry Suit (LES), 396–98, 396

 U.S. Rubber suits, 50

Model 1 G-suit, 100

Model 1 Omni-Environment Suit, 183–84, 183, 237

Model 2 G-suit, 100

Model 2 Omni-Environment Suit, 186, 187–88

Model 3 Omni-Environment Suit, 187–89, 187, 188, 

190, 192

Model 4 Omni-Environment Suit, 192

Model 4A Omni-Environment Suit, 191, 192

Model 5 G-suit, 100

Model 5 Omni-Environment Suit, 193–95, 194

Model 6 G-suit, 100

Model 6 Omni-Environment Suit, 195, 196

Model 7 full-pressure suit, 179–81, 179, 180

Model 7 Omni-Environment Suit, 197, 198–99, 198, 

199, 201–2, 201, 202, 204, 206, 256

Model 8 Arterial Occlusion Suit (AOS), 100, 101

Model 8 Omni-Environment Suit, 203, 204

Model 9 Omni-Environment Suit, 204

Model 10 Omni-Environment Suit, 204

Model 11 Omni-Environment Suit, 202, 204–5

Model 12 Omni-Environment Suit, 204, 205, 206, 209, 

210, 244

Model 13 Omni-Environment Suit, 206, 209

Model 14 Omni-Environment Suit, 209, 239

Model 15 Omni-Environment Suit, 209

Model 16 Omni-Environment Suit, 207, 210–11

Model 17 Omni-Environment Suit, 214

Model 18 Omni-Environment Suit, 208, 214–15

Model 19 Omni-Environment Suit, 215

Model 21 G-suit, 181

Model H suit, 210–11, 212, 215–16, 240–41

Model L suit, 214, 217

Model M suit, 217

Model N suit, 217

Model Q suit, 217

Model R suit, 217–18

Model S (Mark I) suit, 215, 216, 218–20

Moller, Frederick D. “Fred”

 CSU-2/P partial-pressure suit, 166–67, 171

 G-suit development, 83, 92, 99, 107

 G-suit standardization, 105–6

 sizing tariff, development of, 158

Molomut, Norman, 124

Morgan, Thomas R. “Tom,” 174, 176

movie and magazine features about pressure suits, 68–69, 

227

Mukai, Chiaki, 403

Mulka, Mr., 443n161

Munsingwear, 99, 106, 272, 431n145

Murray, Arthur, 15
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

503

Index: M | N

Mustang Survival (Mustang Sportswear, Ltd.), 110

Mutual Defense Assistance Program (MDAP), 109, 

433n186

MX research and development projects

 confidential classification and security related to, 133

 general information about, 421n116, 433n174

 Project MX-117, 52, 68, 105, 179, 195, 237, 244, 

 421n116

 Project MX-829, 133–34, 135, 136

 Project MX-2147, 149

N

nap-of-earth/low-altitude missions, 286

National Advisory Committee on Aeronautics (NACA)

 D558 program, ix, 196, 198, 205–6

 G-suit development, 89

 U-2 aircraft, research with, 151

 X-1 rocket plane program, ix

 X-15 program, ix

National Aeronautic Association, 34

National Aeronautics and Space Administration (NASA)

 Earth resource program. 

See Earth resource program (NASA)

 full-pressure suit use, 362

 hard suits, development of, 38

 human space flight, engineering and management 

 culture surrounding, 382–83

 IVA and EVA study, 371

 lifting body programs. See lifting body programs

 patches on pilot’s suits, 277

 pressure suit development, role in, ix

 Project SOLVE, 357

 S-100 partial-pressure suit use, 318, 319, 322

 Special Advisory Committee on Life Sciences, 91

 SR-71 aircraft, transfer of, 155

 U-2 aircraft, pilots for, 153

 U-2C aircraft, use of, 321

 WB-57F program. See WB-57F aircraft

National Air and Space Museum, 35, 344

National Air Race Derby, 29

National Air Races, Cleveland, 28

National Bureau of Standards, 34, 187, 241

National Carbon Company

 fabrics and materials for suits, 50

 Type 7 pressure suit, 44, 50–51

 XH-7 pressure suit, 44

National Defense Research Committee, 125

National Oil Products Company, 462n53

National Research Council

 G-suit development, 88, 92

 human centrifuges, funding for, 76, 77, 87

 pressure breathing research, 123

NATO nations, sale of suits to, 161

Naval Air Crew Equipment Laboratory (NACEL)

 Berger Brothers suits, testing of, 94–95

 explosive decompression studies, 217

 fabric evaluation by, 189

 full-pressure suit testing, 179

 General Electric suits, testing of, 67

 Goodrich suits, testing of, 215–16, 224

 Goodyear suits, testing of, 54–55, 60

 helmets and carbon dioxide buildup, evaluation of, 217

 Mercury program suits, research on, 233

 name change of, 430n129

 Omni-Environment Suit testing, 184, 187, 192, 199, 

 201, 210, 214–15

 research and research facilities at, 179

Naval Air Development Center (NADC)

 depot for suit maintenance, testing, and logistical 

 support, 265

 MC-2 suit testing, 255, 256

 S1032 suit testing, 394

 standardization of G-suit designs, 109–10

 Wheel centrifuge, 78, 79–80, 79

 X-plane program research and testing, 244

Naval Air Station (NAS) Anacostia, 98

Naval Air Station (NAS) Atlantic City, 223

Naval Air Station (NAS) Norfolk, 223

Naval Air Station (NAS) North Island, 223

Naval Air Station (NAS) Pensacola

Antietam, 232

 human centrifuge at, 77

 Naval School of Aviation Medicine, 77

Naval Air Test Center Patuxent River, 224

Naval School of Aviation Medicine, 77

Navy, U.S.

 air missions, 301

 A/P22P-16 COMBAT EDGE ensemble, 114

 BABM suits, 62–63

 bases of, 274

 Berger Brothers G-suit use by, 93, 94–95

 Bureau of Aeronautics (BuAer), 97, 189, 205–6, 216, 

 222, 240

 D558-2 Skyrocket program, ix

 David Clark G-suit use by, 107

 designation system for suits, 430n123

 Enhanced Anti-G Lower Ensemble (EAGLE), 116–18

 full-pressure suit use, 286, 362

 General Electric pressure suits, 65–66, 68

 Goodrich suits, 61–62, 64, 68
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

504

Index: N

 Goodyear suits, 54–55, 63–65 neck seals S-100 partial-pressure suit, 321
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

505

Index: O

O

Office of Scientific Research and Development (OSRD), 

 Model 18 suit, footwear, 185–86
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

506

Index: O | P

 full-pressure suit oxygen and power supply, xii Firewel regulators and controllers, 154, 158–59, 168, standard masks, 122

P

P2B-1S (B-29) carrier aircraft, 198, 202, 206, 209

P-16 aircraft, 42

P-38 (F-5) Lightning, 95, 124, 149

P-39/P-39D Airacobra, 46, 51, 52

P-40E Kitty-hawks, 84, 84

P-47 Thunderbolt, 56, 95

P-51 Mustang, 95, 106, 107, 149

P-59A Airacomet, 107

P-80 Shooting Star, 107, 127, 127

Palmer, Don, 127

PAOS (Progressive Arterial Occlusion Suits), 99–100, 

117, 118, 119

parachutes and harnesses

 A/P22S-2 full-pressure suit, 271, 273

 Beaupre Multi-Stage Parachute system, 162–65, 163, 

164

 main canopy parachutes, 408

 Red Bull Stratos jump, 165

 S901J suit parachute harness, 326, 326, 328

 S901 suit and A-12 parachute pack, 303

 S1010 suit parachute harness, 338, 338

 S1032 Launch Entry Suit, 383, 383, 384, 384, 391, 

392, 394

 S1035 Advanced Crew Escape Suit (ACES), 401, 403, 

 408

 Space Shuttle crew-escape options, 383, 383, 384, 384
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

507

Index: P

Paradise Ranch, 460n24. See also Groom Lake

Parazynski, Scott E., 403

Park, William C. “Bill,” Jr., 306, 310, 314, 315–16, 335, 

460n31

Parker, Will D. “Billy,” 34, 418n50

partial-pressure suits

 Altitude Protective Garment, 173–74

 breathing process and, xi, 21

 collaborative design efforts, v

 comfort of, 135, 144, 148–49, 153, 162, 168–69

 concept behind and purpose of, x–xi, 121

 continuous-wear suits, 144, 156

 counter-pressure from, x–xi

 CSU-4/P suit. See CSU-4/P partial-pressure suit

 CSU-5/P partial-pressure suit, 172–73

 custom fitting of, 136, 144

 emergency use of, 135

 get-me-down (emergency) suits, xi, 121, 135, 137, 169

 heat fatigue and, 271

 limitations of, xi

 MB-1 partial-pressure suit, 146–47

 MB-2 partial-pressure suit, 147

 mobility and, xi, 167–68, 168, 237

 naming of, x, 127

 protection provided by, xi, xii, 22, 121

 S787 prototype suit, 159

 sizing of, 134, 136, 144, 156, 158, 167, 168

 specifications, 126

 standardization of designs, 135

 success and durability of design, 173

 suit controllers, 154, 158–59, 168, 174

 surplus suits, ads for and sale of, 160, 161, 161

 U-2 program, v, xi

 weight of, 439n70

 X-1 rocket plane program, ix

partial-pressure suits, capstan-operated

 C-1/1A/1AM partial-pressure suits, 167–68

 C-4/4A (S759/S785) partial-pressure suit, 157, 168, 

169

 concept behind and purpose of, xi

 cost of, 132, 133, 134, 138

 CSU-2/P partial-pressure suit, 158, 159, 162, 165–67, 

 169, 171

 double-capstan system, 165–67

 end of development of, 160, 167

 G-suits compared to, 126

 Henry Suit (S-1 partial-pressure suit), 125–30, 129, 

130, 132–34, 134, 135–36, 144, 179, 237, 437n32

 human factors and, v

 MC-1 suit. See MC-1 Featherweight suit

 MC-3 suit. See MC-3/3A partial-pressure suit

 MC-4/4A. See MC-4/4A partial-pressure suit

 S-2 suit. See S-2 partial-pressure suit

 success and durability of early designs, v, 130

 suit designers and aircrews, working relationship 

 between, v

 T-1 suit. See T-1 partial-pressure suits

Pascal (Pa), 17, 20

Pascal, Blaise, 17

Patrick Air Force Base, 271

Patsayev, Viktor Ivanovich, 371

Paul Bert Aeromedical Center, 36

pause, 18

Payne, Dick, 131

PBI (polybenzimidazole) exterior covers, 354, 376, 377, 

378, 464n85

PC-7 turboprop trainer aircraft, 115

Peace Jack F-4E(S) aircraft, 289, 295

Peak, Ira F., 80

Peck, Harry, 210, 217

Penrod, Kenneth E., 182–83, 182, 184, 185, 186, 187

Perier, Florin, 17

Personnel Support Apparel designation system, 262

Peters, Lowell, 30

Petersen, Forrest S., 229, 260

Peterson, David W., 292, 293

Pezzi, Mario, 36

Pfister, William J., 223

Phillips, Frank, 34

Phillips Petroleum Company, 34, 35, 418n50

Photographic Reconnaissance Squadron, 14th, 124

Photographic Reconnaissance Squadron, 28th, 124

photosynthesis, 20

physical elasticity, laws of, 241

physiological effects and risks

 A-12 aircraft, 302

 acceleration, 72–74, 72, 80–83, 81, 425n15

 aeromedical and physiological research, 41–43, 81, 

 89–92

 Blackbird era, monitoring during, 302

 ejections/bailouts, 22

 high-altitude flight, risks associated with, xi, 20, 21, 

 22–23

 oxygen, altitude, and physiological impairment, 20, 

 21, 22–23, 41–43, 122

 oxygen deprivation, 20

 pressure breathing, 21–22

 syncope, 145–46

Physiological Research Unit, Wright Field, 42, 74–75, 

425n24

Physiological Support Divisions (PSDs), 264, 265, 271, 

378
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

508

Index: P

Physiological Training Unit, Tyndall Air Force Base, 264

Piccard, Auguste, 26

Pierce, Harold, 42

Pilatus PC-7 turboprop trainer aircraft, 115

pilot and crew protection equipment

 designers of, vi

 development of, 74–75

 Equipment Laboratory research and development, 

 42–43

See also boots; gloves and mittens; helmets; oxygen 

 masks, supply, and systems; pressure suits

pilots

 A-12 program pilot selection, 305

 attitude toward pressure suits, 262, 286, 294

 crew vans, 349

 fitness and efficiency of, 41, 146

 g-forces, research on effects of, 43

 G-suits, acceptance of by, 94–95, 103–5

 G-suits, effectiveness of, 106, 107

 high-altitude flight stress on, 43

 patches on suits of, 277

 physiological effects and risks. 

See physiological effects and risks

 selection standards, 41

 sense of humor of, 276

See also stress and fatigue

Pilots Protective Assembly. See S1010 Pilots Protective 

Assembly (PPA); S1030 Pilots Protective Assembly 

(PPA); S1031 Pilots Protective Assembly (PPA); 

S1031C common suit Pilots Protective Assembly 

(PPA); S1034 Pilots Protective Assembly (PPA)

Pima Air and Space Museum, 286

Pincus, Gregory, 98

Pinecastle Air Force Base, 132, 438n47

Pioneer Bendix Company, 124

piston-powered aircraft, 142, 237, 301

Pittsburgh Plate Glass Company (PPG) visors, 328, 334, 

462n55

Platenburg, Robert I., 273

Plato, 15

Plexiglas, 419n70

plexiglass helmets, 39, 39, 44–45, 51, 51, 54, 54, 184, 

203, 204, 419n70

Plummer, Henry Stanley, 91

pneumatic lever. See capstans

pneumotherapy, 122

polybenzimidazole (PBI) exterior covers, 354, 376, 377, 

378, 464n85

Poole, Forrest R., 262, 263

Poppen, John R. “Jack,” 80–81, 83, 97

Poppen Belt, 81, 82

Porter, Adrien, 76

Porter, Delewis “Dee,” 356, 357, 358–60

Post, Wiley

 altitude-record attempts, 29–30, 34–35, 36

 around-the-world flights, 29

 aviation career, 28

 commercial pilot license, 28

 cost of pressure suit, 30, 417n35

 death of, 35

 high-altitude flight, prediction about, 121

 loss of eye, 28

 MacRobertson Race, 29, 32

 pressure suit development, v, ix, 29–35, 31, 32, 35, 

36, 43, 215, 417n35

Winnie Mae, 29–30, 31, 32, 33, 34–35, 34, 35

Potez 506 aircraft, 36

Potez Airplane Company, 36

Power, Thomas S., 156

Powers, Francis Gary, 156, 301–2, 314

PPG (Pittsburgh Plate Glass Company) visors, 328, 334, 

462n55

P/Q pressure-breathing mask, 175, 176, 177

Prahl, Val, 285

Prather, Victor A., 232–33

Pratt & Whitney

 J57 engine flameout incident, 223

 J58 engines, 312, 314

 J75 engines, 312

 R-1340 Wasp engine, 28

 R-4360 engines, 141, 142, 440n89

 T-1 and S-2 suit use by, 141

 TF33 turbofan engines, 286

Prescott, Charles W., 75

Presidential Commission (Rogers Commission) to study 

Challenger accident, 382–83

pressure

 altitude and, 17

 atmospheric pressure, 16–17

 concept of, 16

 measures of, 17, 20–21

 vacuum and, 16–18

 vacuum pump experiment, 17, 414n14

pressure-breathing clothing. See counter-pressure clothing

pressure breathing for altitude (PBA), 113

pressure breathing for G (PBG), 113

pressure-breathing masks

 A-13 pressure-breathing mask, 123–24, 127, 130, 132

 Air Force requirements, 378

 concept behind and development of, 122–24

 G-suits, use with, 110

 Launch Entry Helmet, limitations of, 381
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

509

Index: P | Q | R

 Model 7 suit pressure-breathing mask, 180, 181

 P/Q pressure-breathing mask, 175, 176, 177

 XA-13 pressure-breathing mask, 123–24

pressure breathing/positive pressure breathing (PPB), 

21–22, 23, 30, 122–24

pressure-breathing vests. See vests

pressure suits

 advances in design and development, vi, ix

 aircraft advancements and protection requirements 

 from, 121, 237, 238, 239, 243

 awe associated with, 15

 collaborative design efforts, v–vi

 depot for maintenance, testing, and logistical support, 

 264–65

 designation system for suits, 44, 181, 262, 301, 318, 

 362, 430n123

 diving suits compared to, ix, 25

 early designs, 25–28, 27

 emergency incidents and evaluation of, 223

 funding for, 363

 future of, vi

 G-suits, confusion between, ix–x

 human factors and, v

 inspection and maintenance of, 264–65, 340

 international efforts, 35–41, 38, 39, 40, 41

 manufacturers of, 362–63

 mobility and, 30, 31, 37

 pilot attitude toward, 262, 286, 294

 purpose of, ix, 25

 similarity verification process, 468n78

 spacesuits compared to, xi–xii

 standardization of designs, 105–6, 109–10, 135, 258, 

 262

 successful designs, 121

See also full-pressure suits; partial-pressure suits

Price, Bruce B., 132

Priestly, John G., 26

Progressive Arterial Occlusion Suits (PAOS), 99–100, 

117, 118, 119

Project 7164 (Aerospace Protective Technology project), 

293–95

Protection Incorporated

 AOH-1 (Aviator Oxygen Helmet), 378

 Gentex, purchase of, 380

 heated visor lens, development of, 269

 HGU-15/P helmet, 378, 380

 neck rings, 306

Prototype High Altitude Flying Outfit (PHAFO) suits

 color of, 298, 299

 David Clark Company suits, 296–99, 297, 298

 donning and doffing, 296–97, 299

 fabrics and materials, 296, 297, 299

 gloves, 296

 helmets, 296

 ILC suits, 296, 299

 modular ensemble, 296–99, 298

 weight of, 299

PSDs (Physiological Support Divisions), 264, 265, 271, 

378

Pulsatile pressure suit, 98, 98

Pure Oil Company, 34, 34

pursuit airplanes. See fighter aircraft (pursuit airplanes)

Puy-de-Dôme experiment, 17

Q

Q-12 drone, 314. See also M-21/D-21 aircraft/drone 

combination

Quick-Don Mask (QDM), 409

R

R-12 aircraft, 322. See also SR-71 Blackbird aircraft

R-1340 Wasp engine, 28

radiation exposure and protection, xii, 43

Ralph E. Darling Company, 217

Ralston, William P., 127

Randall, Francis E., 123

RAND Development Corporation, 241–43

Ranger, 224, 226

Ratermanis, John, 369

Ray, Walt, 314

RB-36 reconnaissance aircraft, 149, 149

RB-57 Canberra, 149, 155, 156, 286. 

See also WB-57F aircraft

RB-66 Destroyer, 149, 156

Reaction Motors

 XLR11 rocket engines, 209, 447n46

 XLR99 rocket engines, 244

readyrooms, air-conditioned, 224, 226

Reagan, Ronald, 382, 383

reconnaissance aircraft and missions

 China, missions over, 313, 315

 competition between reconnaissance programs, 316

 development of aircraft, 149

 drone use, 314, 315

 manned flights, cessation of, 314

 Soviet Union, missions over, xi, 149, 153, 154, 301–2, 

 313, 314 See also specific aircraft
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

510

Index: R

Reconnaissance Squadron (Provisional), 4402nd, 354

record-setting flights

 Adam Aircraft A700 prototype, 464n93

 Adam flight, 41, 419n80

 balloon flights, 233

 competition for, 29–30, 121

 criteria for, 418n59

 D558 program, 139–40, 202, 206, 209

 F-15A Streak Eagle flight, 291–93, 292, 293, 294

 French flights, 36–37, 419n63

 Italian flights, 36

 Kittinger and Excelsior project, 162–65, 163, 164

 MiG-25 aircraft, 293

 Post flights, 29–30, 34–35, 36

 SR-71 Blackbird aircraft, 330, 344

 Sukhoi Su-27 aircraft, 293

 Swain flight, 41, 419n78

 time-to-climb record flight, 291–93, 292, 293, 294

 X-1 aircraft, 135

 YF-12A interceptor aircraft, 309

Red Bull Stratos jump, 165

Reed, Al C., 47, 52, 55, 124

Reisman, Garrett, 404

Republic F-105 Thunderchiefs, 380

Republic of China Air Force, 153, 156, 337, 338

Republic P-47 Thunderbolt, 56, 95

Republic XF-12 Rainbow, 149

Republic XF-103/F-103 aircraft, 237, 240

Resch, Joseph A., 53

rescue balls, 365–66, 366

Resnick, Judith A., 382

restraint layer

 A/P22S-2 full-pressure suit, 263, 266, 269

 A/P22S-4 full-pressure suit, 283–84

 full-pressure suits, v

 MC-2 full-pressure suit, 247, 248, 250, 253

 S901 Flying Outfit, Full-pressure, High Altitude, 

 Multi-Layer, 306, 308

 S1032 Launch Entry Suit, 389

Restricted Area 51 (Area 51), vii, 150, 460n24

Retrograde Inflation Anti-G Suit (RIAGS), 117, 118–19, 

118, 119

Rhode, Richard V., 80

RIAGS (Retrograde Inflation Anti-G Suit), 117, 118–19, 

118, 119

Richardson, Ralph N., 271

Ride, Sally K., 382

Ridge, Mark Edward, 25–28, 30, 40

Ridley, Jackie L. “Jack,” 135

Rinehart, Dixie, 369

Ring, Samuel, 27

Ritzinger, Frederick R., 293

RJ43 ramjet, 314, 315

Robertson, Ken V., 83–84

Robertson, MacPherson, 29, 417n27

Robins Air Force Base, 363

Robinson, Steven K., 403

Rocketdyne AR2-3 rocket engines, 140

rocket engines. See engines

rocket sleds

 A/P22S-2 suit testing, 267

 MC-2 suit testing, 257

 S901 suit testing, 306

Sonic Wind I rocket sled, 162

Rocky 911 boots, 401

Rogers, Will, 35

Rogers, William P., 382

Rogers Commission (Presidential Commission) to study 

Challenger accident, 382–83

Roosevelt, Franklin Delano, 28, 125

Ross, Malcolm D., 231–33

rotative couch, 74

Royal Air Force (RAF)

 Berger Brothers G-suits, 88

 David Clark Company G-suits, 88

 Fighter Command and Battle of Britain, 83

 Franks Flying Suit, 84, 87–88

 Fulton leggings, testing of, 82–83, 87, 92

 get-me-down (emergency) suits, 175–76

 high-altitude flight, 45

 Institute of Aviation Medicine, 174, 175

 jerkin and jerkin-based ensembles, 174–77, 177, 265, 

 274

 pilot protective clothing, conference on, 103

 pressure-breathing apparatus, development of, 124

 T-1 and S-2 suit use by, 140

Royal Australian Air Force (RAAF)

 air-conditioned van for pilots, 84

 A/P22S-4 suit use, 285, 286, 457n118

 Cotton Aerodynamic Anti-G Suit, 83–85

 CSU-4/P suit use by, 172

 Curtiss P-40E Kitty-hawks, trials with, 84, 84

 Kelly One-Piece (K.O.P.), 85–86

 University of Sydney centrifuge, 75, 84

See also Australia

Royal Canadian Air Force (RCAF)

 Berger Brothers G-suits, 88

 Camp Borden, 87, 428n84

 David Clark Company G-suits, 88, 109

 Franks Flying Suit, 84, 86–88, 109
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

511

Index: R | S

 human centrifuge, 51, 76 S-100 suit development, 316–18

S

S-1 partial-pressure suit (Henry Suit), 125–30, 

 development and specifications, 316–22, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

512

Index: S

S794-5 full-pressure suit, 256–57 pocket locations, 306, 308 development and specifications, 324–31, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

513

Index: S

S931 full-pressure suit, 272, 277 visors, 338, flotation system, 339
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

514

Index: S

S1031C common suit Pilots Protective Assembly (PPA), restraint layer, as S1030 replacement, 341
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

515

Index: S

 S1032 compared to, 399–401, 399, 401

 S1034, similarity to, 411, 468n78

 S1034 as basis for design, 398, 399

 S1034 compared to, 400, 401, 402

 sizing of, 409–10

 suit controllers, 400

 underwear, 408

 urine-collection system, 401, 408

 WB-57F program use, 294

 windblast evaluation, 411

 wrist rings, 399

 zippers and fasteners, 403

Saab JAS-39 Gripen aircraft, 115–16

Sabo, Stephen C., 215

SAC. See Strategic Air Command (SAC)

Salathé, Charles-Auguste, 74

Salmon, Herman R. “Fish,” 140, 141

Salyut space station, 370

Sample, Fred M., 25, 30, 415n3

San Antonio Air Materiel Area, Kelly Air Force Base, 290

Sasine, Kenneth, 358–60, 464n93

satellites, reconnaissance, 314

Schafer, Lauren W., 396

Schalk, Louis W. “Lou,” Jr., 306, 311

Schirra, Walter M., Jr., 234

Schlosser, James D., 375, 381

Schneider, Ed, 341

Schneider Trophy 

(Coupe d’Aviation Maritime Jacques Schneider), 72

School of Aerospace Medicine (Air Force)

 Benson as commandant, 97

 Boyle’s Law Suit, 293–95

 G-suit research, 111

 jerkin and jerkin-based ensemble testing, 174, 175–76

 S1032 suit testing, 394, 396–98

 Tactical Life Support System program, 111, 112

School of Aviation Medicine (Air Force), 153, 295, 

417n37

School of Aviation Medicine (Army)

 Armstrong as commandant, 75

 Brooks AFB/Brooks Field, 42, 74

 Mitchel Field, 42

 Randolph Filed, 75

Schroeder, Harry, 94–95, 103–4

Scobee, Francis R., 382

Scott, Kenneth, 214

Scott, W.E., 60–61

Scott Air-Pak, 154

Scott Aviation, 154

SDB-3A Dauntless, 103

Seamless Rubber Company, 93

search and rescue operations, colors for, 171, 299, 

354–55, 394

Sears, Roebuck, and Co., 107, 269

seat kits

 advantages over back kits, 258

 A/P22S-2 full-pressure suit, 277

 A/P22S-2 suits, 271, 273

 C-4/4A suits, 168

 configurations and purpose, 219, 448n74

 Mark III suit, 222

 MC-2 suits, 258

 MC-3/3A and MC-4/4A suits, 158–59, 159

 SR-71 Blackbird aircraft, 324

 X-15 seat kits versus back kits for suits, 256, 258, 273, 

 277

Sellers, Piers, 404

Senior Bowl operations, 315

Senior Crown program, 322–24, 334, 363

Senior Year program, 363

Sessums, John W., 46

Sevareid, Eric, 153

Shamrock Oil, 462n53

Shaw, Louis Agassiz, 75

Shepard, Alan B., Jr., 234

shirtsleeve environments

 B-52 Stratofortress, 156

 B-58 Hustler bombers, 156, 210

 bomber aircraft, 156, 210

 Mercury program, 235

 Space Shuttle, 379

 Space Shuttle Program, 365, 366, 374

shoes. See footwear

Shook, Donald H., 57

Siebe, Augustus, 26, 416n11

Siebe, Henry, 416n11

Siebe Gorman & Company, 26–27, 40–41, 41, 

415–16nn10–11

Sierracin Corporation, 269

Silver Snoopy Award, vii

similarity verification process, 468n78

Simmons, David G., 161, 162, 165

siphon, limits of, 16

Sir Hiram Maxim’s Captive Flying Machines, 71, 

424n5–6

Sivel, Henri-Theodore, 41

Slayton, Donald K. “Deke,” 79, 234

Smith, Michael J., 382

Smith, Roger J., 292, 293

Smith, Wesley L., 32–33

Smithsonian Institution, 35, 344

Snider, Lester M., 222
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

516

Index: S

Snoopy Cap communications carrier, 386, full-pressure suits, development of, 362, 366–67 S1035 suit. 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

517

Index: S

 STS-79, 406

 STS-80, 406

 STS-81, 406

 STS-82, 407

 STS-83, 407

 STS-84, 407

 STS-85, 407

 STS-86, 407

 STS-87, 407

 STS-88, 407

 STS-89, 407

 STS-90, 407

 STS-91, 407

 STS-92, 407

 STS-93, 407

 STS-94, 407

 STS-95, 403, 407

 STS-96, 407

 STS-97, 407

 STS-98, 399, 407

 STS-99, 407

 STS-101, 407

 STS-102 through STS-135, 407

 STS-103, 407

 STS-106, 407

 STS-107, 408, 410–11

 STS-129, 399

 STS-132, 404–5

Space Station, 371, 410

spacesuits

 development and manufacturing of, 363

 for EVA, 365

 full-pressure suits as, 217, 233–35, 234

 Mark III suit testing and, 223, 224

 Mark IV suit modification, 231, 233, 234, 235

 as pressure suit, 25

 pressure suits compared to, xi–xii

 reflective fabric for, 259, 260–61, 261

 T-1 and S-2 suits not spacesuits, 136

 T-1 suits publicized as, 140

See also Apollo program; Gemini program spacesuits; 

 Mercury program

Spain, 36, 39–40

spatial disorientation, 43

SPD-117 full-pressure suit, 232, 235

special project suits

 David Clark Company suits, 279

 flotation system, 316

 full-pressure suit use, 264

 S901H suit. See S901H special projects suit

 S901J suit. See S901J Pilots Protective Assembly (PPA) 

speed jeans, 110. See also CSU-13B/P G-suits

Spencer, Inc., 92

Spencer Abdominal Support Belt, 92

Spencer Ltd., 92

Spencer Supports Ltd., 92

Sperry Gyroscope, 76, 80

Spitfire aircraft

 Franks Flying Suit, testing of, 87

 Mk IX aircraft, 437n18

 Mk V aircraft, 85, 85

 PR.XI aircraft, 124, 125, 437n18

Spooner, David C., 104, 115, 126

Sprague, Stanley, 274

Sprengel, Hermann, 18

Sprengel pump, 18

SR-71 Blackbird aircraft

A-12 revival plan and Beale AFB airspace, 316 

aircraft design and development, 127

basis for design, 322

black painted surfaces, 311

breakup of SR-71A and suit performance, vi, 409, 

 410, 411

cockpits, pressurized, 377–78

David Clark Company suits for, 279

depot for suit maintenance, testing, and logistical 

 support, 265

designation as SR, 322–23, 461n41

Edwards AFB as base for, 324

ejection seats, 323, 324, 374, 375, 403

first flight, 314, 323–24

fleet size, 324

flotation system for crew, 395

operational flights, delivery for, 324

as Oxcart replacement, 316

parachute, main canopy, 408

Physiological Support Division, support from, 265

pressure suit requirements, vi, 363, 403

range and capabilities, 322, 322, 330, 344

reconnaissance missions, 322

reconnaissance sensors and equipment, 311

record-setting flights, 330, 344

retirement of, 363

S901J Pilots Protective Assembly, 324–31, 325, 326, 

327, 328, 329, 330, 331, 334, 339, 409, 410, 411

S1030 and S1030A suits, hardware sharing between, 

 378

S1030 Pilots Protective Assembly, 334, 339–41, 340

S1031C common suit Pilots Protective Assembly, 334, 

 349, 350, 351, 354

seat kits, 324

Senior Crown program, 322–24, 334, 363
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

518

Index: S | T

 SR-71B trainers, 324

 test flights, 323–24

 titanium construction, 329

 transfer of aircraft to NASA, 155

Stanley, Robert M., 51–52

Stapp, John Paul, 77, 162, 258, 264

Stargazer, Project, 165, 166

Stevens, J., 30

Stewart, William K., 82–83, 87, 427n58

Straightaway garment, 96–97, 98–99

Strategic Air Command (SAC)

 bombing strategy, 286

 CSU-4/P suits, 171

 MB-5 helmet use, 139

 pressure suit requirements, 142, 144, 156, 239

 pressure suit use, 159–60

 SR-71 aircraft use, 322

 T-1 suit use, 141

Strategic Reconnaissance Wing, 9th, 324

Strato Equipment Company

 BABM suits, 46, 62, 179

 founding of, 179

 Model 7 full-pressure suit, 179–81, 179, 180

Strato-Lab environmental chamber, Boeing, 47, 59

Strato-Lab project, 231–33

stratopause, 20

stratosphere, 18–20, 29

Strato-Suit. See Type 3 “Strato-Suit”; Type 5/5E “StratoSuit”; Type 6/6A/6B “Strato-Suit”

Streak Eagle, 175

Streak Eagle, 292, 293, 293, 294

stress and fatigue

COMBAT EDGE and, 114

 full-pressure suits and, 237

 heat fatigue and partial-pressure suits, 271

 high-altitude flight and, 43

 partial-pressure suits with full-pressure helmets, 317–18

 suit-induced, v, vi, 56, 350–51

Strughold, Hubertus, 82

suit controllers

A/P22S-2 full-pressure suit, 268, 272, 276, 283

 A/P22S-6 full-pressure suit, 291

 Firewel automatic controllers, 216–17

 Firewel controllers, 154, 276

 Mark IV pressure suit, 276

 MC-2 full-pressure suit, 256

 Omni-Environment Suit, 198, 201, 202, 203

 partial-pressure suits, 154, 158–59, 168, 174

 S-100 partial-pressure suit, 320–21

 S901J Pilots Protective Assembly, 329

 S1030A Ejection Escape System suits, 378

 S1030 Pilots Protective Assembly, 393, 394

 S1032 Launch Entry Suit, 391, 393, 394, 400

 S1034 Pilots Protective Assembly, 358

 S1035 Advanced Crew Escape Suit, 400

Sukhoi Su-27 aircraft, 293

Sullivan, J.E., 206

Superior, Lake, 282

Supermarine S.6B aircraft, 72, 73

Supermarine Spitfire aircraft. See Spitfire aircraft

supersonic aircraft

 fighter aircraft, 301

 pressure suit development for, 135

surplus suits and helmets, ads for and sale, 160, 161, 161

Sustained Tolerance for Increased G G-trouser, 114

Swain, F.D.R. “Ferdie,” 41, 41, 419n77–78

Sweden

 Libelle G-Multiplus G-suit testing, 115–16

 pressure-breathing (counter-pressure) vest and trouser 

 use, 174

 Project SOLVE, 357

 Tactical Flight Combat Suit (TFCS), 110

Switzerland, 115

syncope, 145–46

Systems Research Laboratories, 118

T

T-1 partial-pressure suits

 contracts for, cancellation of, 156–57

 cost of, 138

 development and specifications, 133, 136–41, 137, 

138, 139, 146, 240

 distribution and use of, 140–41

 long underwear use with, 138, 144

 mobility of suits and ejection initiation, 167–68, 168

 S393 suit, 136

 sizing of, 136, 144

 sleeve length, 144

 surplus suits, ads for and sale of, 161

 T-1A suit, 156–57

 weight of, 136, 439n70

T-33B/TO2/TV2 Shooting Star trainer 

(T-33 T-Bird trainer), 193, 209, 256–57, 445n23

T-38 aircraft, 395

Tabor, Richard H., 221, 223

Tactical Air Command (TAC)

 air-conditioned vehicles for pilots, 226

 aircraft design and development, 146

 A/P22S-2 suit testing and use, 274
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

519

Index: T | U

 A/P22S-3 suit use, 274

 bases of, 274

 high-altitude flight, 286

 jerkin and jerkin-based ensembles, 274

 MC-3/3A suits, 156

 pressure suit requirements, 155–56, 295–96

Tactical Flight Combat Suit (TFCS), 110

Tactical Life Support System (TLSS) program, 111–13, 

114, 160

TAC Trucks, 226

Tagboard, 314–16

Taiwan (Republic of China) Air Force, 153, 156, 337, 338

Taylor, Rowena, 463n78

temperature and exposure protection

 A-12 ejection and S901 suit, 303, 304–5

 altitude and, 18, 19, 20, 23, 25

 early suit designs and protection from cold, 27

 liquid-cooling garments, 173–74, 408–9

 in stratosphere, 18–20

 suit performance requirements, vi, xii, 240

 suit performance testing, 281–82

 thermal exposure, 22, 23, 42

 water-immersion protection, xii, 282, 393, 394, 395

Tempier, Étienne, 15–16

Terylene fabric, 274

Test Location (The Ranch), 150. See also Groom Lake

Test Pilot School (Aerospace Research Pilots School), 265, 

278

TF33 turbofan engines, 286

TF-104G trainer aircraft, 176

TFCS (Tactical Flight Combat Suit), 110

The Ranch (Test Location), 150, 460n24. 

See also Groom Lake

thermopause, 20

thermosphere, 20

Thomas, Bredette C. “B.C.,” Jr., 343

Thompson, Robert H., 83–84

Thompson Trophy Race, 132

3M (Minnesota Mining and Manufacturing Company) 

fabric, 210

thrust bearing joints, 174, 192–94, 193

Thurston, Albert P., 71, 73, 424n3

Tissandier, Gaston, 41

Titanium Goose trainer, 312

TLSS (Tactical Life Support System) program, 111–13, 

114, 160

TO2/TV2/T-33B Shooting Star trainer 

(T-33 T-Bird trainer), 193, 209, 256–57, 445n23

Todd Shipyards, 154

Toepler, August, 18

Toepler pump, 18

tomato-worm suit, 56–57, 57, 195. See also XH-5 pressure 

suit (tomato-worm suit), B.F. Goodrich Company

torr, 17, 20

Torricelli, Evangelista, 16–17

Torricelli’s Theorem, 17

Torrick, Ray, 315–16, 346, 460n31

Towle, Joe, 124

TR-1 aircraft, 348

tractor rocket-extraction system, 383–84

Transcontinental and Western Airlines (TWA), 35, 

418n54

transverse acceleration (Gx), 72, 73

Trans World Airlines, 418n54

Trilok fabric, 173, 221, 228, 263

Tripp, Lloyd D., Jr., 118

tropopause, 18

troposphere, 18

trousers

 extended-coverage G-trousers, 113, 114, 116

 inflatable, 123

 jerkin-based ensemble, 176

Truax Air Force Base, 279

Truly, Richard H., 376

TSR.2 aircraft, 174

Tupolev Tu-4 bomber aircraft, 146–47

turbojet engines. See engines

TV2/TO2/T-33B Shooting Star trainer 

(T-33 T-Bird trainer), 193, 209, 256–57, 445n23

Tyndall Air Force Base, 264, 265, 279, 318

Type 1 pressure suit, United States Rubber, 44–45, 44

Type 2 pressure suit, United States Rubber, 44, 45

Type 3 “Strato-Suit,” B.F. Goodrich Company, 43, 

420n89

Type 4/4A pressure suit, United States Rubber, 44, 49

Type 5/5E “Strato-Suit,” B.F. Goodrich Company, 44, 

45–46, 47, 61–62, 62, 63

Type 6/6A/6B “Strato-Suit,” B.F. Goodrich Company, 

44, 47, 57

Type 7 pressure suit, National Carbon Company, 44, 

50–51

Type 8/8A pressure suit, B.F. Goodrich Company, 44, 47

Type 9/9A pressure suit, Goodyear Tire & Rubber, 44, 

47, 53–54, 53, 420n102

Type A (altitude) suits, 45, 420n90

Type G (gravity) suits, 45, 420n90

Typhoon fighters, 114

U

U-2 spy plane “Dragon Lady”

 A-12 aircraft compared to, 302

 advances in suit development and, vi
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

520

Index: U

 A/P22S-2 full-pressure suit use, 271–72, 317 S901/S901J suit use, 334, 335 Mark III suit, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

521

Index: U | V

 Type 2 pressure suit, S1034 Pilots Protective Assembly, 357–58, 408

V

vacuum

 portable air-conditioning equipment, 225–26, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

522

Index: V | W

 A/P22S-6 full-pressure suit, Vultee SNV-1 trainer/BT-13A Valiant, 63

W

WADC (Wright Air Development Center), 205, 237

 phase-out of, 355
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

523

Index: W | X

W.L. Gore & Associates, 463n78 Physiological Research Unit, 42, 74–75, 425n24

X

X-1 aircraft. 

 A/P22S-2 suit testing and use, 267, 268–69, 273, 
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

524

Index: X | Y | Z

XF4D Skyray, 199, 200, 201–2, 204, 211

XF-11 aircraft, 149

XF-12 Rainbow, 149

XF-103/F-103 aircraft, 237, 240

XF-104 aircraft, 141

XH-1/XH-1C pressure suit, B.F. Goodrich Company, 44, 

51, 51, 54, 56

XH-2 pressure suit, United States Rubber, 44, 47, 54

XH-3/XH-3A/XH-3B pressure suit, Goodyear Tire & 

Rubber, 44, 54–56, 54, 60, 66, 68

XH-4 pressure suit, United States Rubber, 44

XH-5 pressure suit (tomato-worm suit), B.F. Goodrich 

Company, 44, 56–57, 57, 60, 60, 61, 68, 195

XH-6/XH-6B pressure suit, B.F. Goodrich Company, 44, 

54, 56, 56

XH-7 pressure suit, National Carbonic, 44

XH-8 pressure suit, 44

XH-9 pressure suit, Goodyear Tire & Rubber, 44

XLR11 rocket engines, 209, 447n46

XLR99 rocket engines, 244

XMC-2-DC suits, 243, 244, 246–53, 248, 249

XMC-2-ILC suits, 232, 243, 244, 245, 246, 248, 252–53

X-planes, Round One, 244

X-planes, Round Two, 244

XS-1 (X-1) rocket-powered aircraft

 altitude restrictions on flights, 135

 emergency use of partial-pressure suit, 135

 hatch size, 131, 132

 Henry Suit for, 132, 133, 134

 photo of, 131

 pressure suit for, v, ix, 126, 244

 record-setting flights, 135

 X-1A flight, 15

 X-1E flights, 139, 140

 Yeager flight, 134, 135

Y

Yale University

 capstan-controlled leg pressure G-suits, x, 115, 126

 John B. Pierce Laboratory, 122

Yeager, Charles E. “Chuck,” 133, 134, 135, 140

YF-12A/AF-12 interceptor aircraft

 cancellation of, 308

 contract for development, 308

 design and development of, 308

 Edwards AFB as base for, 324

 fleet size, proposed, 308

 Groom Lake testing, 308

 number built, 240

 Physiological Support Division, support from, 265

 range and capabilities, 240, 307

 record-setting flights, 309

 S901F full-pressure suit, 308–10, 309

 S901J suit, 327, 331

 titanium construction, 329

 weapons systems, 307, 308

YF-12/SR-71 Test Force, 324

YF-86D aircraft, 137

YF-93A aircraft, 137

YF-100 Super Sabre, 301

Yielding, Raymond E. “Ed,” 344

YKK Group (Yoshida Manufacturing Corporation/

Yoshida Kogy Kabushikigaisha), 352, 443n161

Young, James O., 134

Young, John W., 375, 376, 380, 382

Z

Z-3 (G-4/G-4A) suits, 107–8, 109, 222, 439n70

Zero aircraft, 85, 94

zippers and fasteners

 airtight zipper, development of, 54, 180

 A/P22S-2 full-pressure suit, 173, 263, 266, 266, 267, 

 268, 268, 269, 272, 274, 283, 285, 305

 A/P22S-4 full-pressure suit, 283

 BABM suits, 62

 Berger Brothers G-suits, 92, 93, 94

 Cotton Aerodynamic Anti-G Suit, 85

 CSU-2/P partial-pressure suit, 167

 CSU-4/P partial-pressure suit, 171

 CSU-5/P partial-pressure suit, 172–73, 443n161

 Durkee Atwood Company zipper, 180

 Franks Flying Suit, 87, 88

 full-pressure suits, 263

 Gemini program suits, 283

 Goodrich suits, 56, 61, 69, 218

 Goodrich zippers and fasteners, 172–73, 274, 352

 Goodyear suits, 53, 54, 63, 64

 Goodyear zippers, 54, 180

 Henry Suit (S-1 partial-pressure suit), 130, 133

 Mark IV suit, 180, 216, 228

 MC-3/3A partial-pressure suit, 155, 159

 Model 7 full-pressure suit, 180

 Omni-Environment Suit, 181, 184, 185, 186, 187, 

 190, 201, 205, 205, 206, 207, 210–11

 S-100 partial-pressure suit, 321

 S901 full-pressure suit, 305, 306, 310

 S901H special projects suit, 310

 S901J Pilots Protective Assembly, 306, 328

 S970 full-pressure suit, 306, 310, 311
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

525

Index: Z

 S1031 Pilots Protective Assembly, 352
Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle | Dennis R. Jenkins

526

About the Author and Acknowledgements

ABOUT THE AUTHOR 

Dennis R. Jenkins has spent 30 years as an engineer and 

manager for various contractors on the Constellation, 

Space Shuttle, and X-33 programs. In addition, he has 

served in a staff capacity on the Columbia Accident 

Investigation Board (CAIB), the President’s Commission 

on Implementation of U.S. Space Exploration Policy, 

and the Return-to-Flight Task Group, and spent a year 

as the Verville Fellow at the Smithsonian’s National Air 

and Space Museum. He has authored several dozen books 

chronicling the history of various aerospace projects 

including the Space Shuttle, X-15, North American 

XB-70 Valkyrie, and Convair B-36. Jenkins is active in 

promoting the preservation of aerospace historical archives 

and records. He presently lives in Cape Canaveral, FL.

ACKNOWLEDGEMENTS

This book would not be possible without the following 

design and editorial support: the design work of 

Lillian Gipson; the initial editing of James Schultz; 

and the design and editorial services of the NASA 

Headquarters Communication Support Services Center, 

specifically Christopher Yates and Benjamin Weinstein 

for editorial work and Tun Hla, who saw the book 

through the publication process.
Anybody who has watched many movies or 

television shows has seen them—the ubiquitous 

silver suits worn by pilots as they explore the unknown. They are called pressure suits, and one 

can trace their lineage to Wiley Post or, perhaps, 

a bit earlier.

There are two kinds of pressure suits: partial 

pressure and full pressure. David Clark, the 

man, once pointed out that these were not very 

good names, but they are the ones that stuck. 

In a partial-pressure suit, the counter-pressure 

is not as complete as in a full-pressure suit, but 

it is placed so that shifts in body fluids are kept 

within reasonable limits. On the other hand, a 

full-pressure suit, which is an anthropomorphic 

pressure vessel, creates an artificial environment 

for the pilot. 

One type of pressure suit is not necessarily 

“better” than the other, and both partial pressure and full pressure suits are still in limited 

use around the world. Both type of suits have 

benefits and limitations and, by and large, pilots 

dislike both, even while acknowledging their 

necessity. For the past 60 years, they have been 

an indispensible part of a small fragment of the 

aviation world.

Although space suits, which differ from pressure 

suits in subtle, but important ways, have been 

well covered in literature, pressure suits have 

gone unheralded except as introductions to 

the space suit histories. This book is an attempt 

to correct that, and covers pressure suits from 

the beginning through the end of the Space 

Shuttle Program.

Legendary test pilot Capt. Iven C. Kincheloe, Jr., poses in front of a 

McDonnell F-101 Voodoo wearing an MC-3 partial pressure suit. 

Kincheloe became the first person to fly above 100,000 feet while 

flying the Bell X-2 using a partial pressure suit. 

– Dorothy Kincheloe Collection

Another legendary test pilot, A. Scott Crossfield shows off an early 

David Clark Company MC-2 full-pressure suit in front of the 

Wright Field altitude chamber. The sign indicates the chamber 

was limited to 85,000 feet. Of note is the thickness of the raised 

entry door. 

– National Archives College Park Collection

National Aeronautics and Space Administration

Headquarters

300 E. Street, SW

Washington, DC 20546

NASA SP-2011-595