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Produced by the NASA Center for Aerospace Information (CASI)
1

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T

FINAL ^,EPORT

SPACE TELESCOPE

DESIGN DEVELOPMENT MOCKUP

CONTRACT NAS8-33272

(NASA-Ch-170948) SPALE TE1kSCCPk tlilaI iv84- 16097

heNor t (css*:x Lurp.) 34 F tic. A03 /MF AU 1

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G3/89 18001

SEPTEMBER 139 983

ESSEX REPORT NO. H-E3-06

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HU NTSV I IJ[,E FACI LI'L'Y • 3322 MemoriJ Nirkway South, Huntsville, Alabama 35801 
Prepared By:

Edwin C. Pruett

Kem B. Robertson

Charles N. VanValkenburgh

Wayne Reed

ESSEX CORPORATION

3322 South Memorial Parkway

Huntsville, Alabama 35801

September 13, 1983

H-83-06

ESSEX

SPACE TELESCOPE FINAL REPORT

Contract No. NAS8-33272

Prepared For:

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

George C. Marshall Space Flight Center

Marshall Space Flight Center, Alabama 35812

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FOREWORD

This report describes the tasks performed and end products

developed by Essex for NASA's Marshall Spare Flight Center under

contract NAS8-33272. During the 4^ year contract, Essex designed and

fabricated Space Telescope mockups, servicing tcols, spares carrier

mockups and a flight support system. Essex also supported the Neutral

Buoyancy Simulator tests by installing the test hardware, providing

divers during the tests, preparing test plans and reports and modifying

the test hardware as needed.

This report describes the contract tasks and end products and

presents some observations made during the contract performance.

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TABLE OF CONTENTS

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FOREWORD

LIST OF FIGURES

LIST OF TABLES

1.0 INTRODUCTION

1.1 purpose of Contract

1.2 Contract History

2.0 TECHNICAL APPROACH

2.1 Task A - Review Space Telescope Drawings

2.2 Task B - Prepare Mockup Drawings

f 2.3 Task C - Fabricate Mockups

k 3.0 END ITEM DESCRIPTION

3.1 Space Telescope

3.1.1 Space Telescope Mockup

3.1.2 Space Support Equipment

3.1.3 Test Plans

3.2 Spacelab

3.2.1 Spacelab 1 Experiment Hardware

3.2.2 Spacelab 2 Pallets & Experiment Hardware

3.3 AXAF

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4.0 TEST OBSERVATIONS

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LIST OF FIGURES

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Figure 1: Space Telescope Contract History 3

Figure 2: ST Mockup Configuration 6

Figure 3: Space Telescope NBS Mockup 7

Figure 4: Aft Shroud Half-Section 8

' Figure 5: Focal Plane Assembly 9

Figure 6: Axial Scientific Instrument Changeout 10

Figure 7: Star Tracker Changeout 11

Figure 8: Wide Field Planetary Camera Changeout 12

Figure 9: Fine Guidance Sensor. Changeout 13

r f Figure 10: Equipment Section ORU Changeout 14

Figure 11: Solar Array Latch Release 15

" Figure 12: Solar Atrav Jettison Clamp Removal 16

Figure 13: Flight Support System Cradle 18

Fig::ze 14: FSS Berthing Ring 19

Figure 15: ORU Spares Carrier and Transfer Device 20

Figure 16: Spares Carrier - View from Space Telescope 21

Figure 17: Transfer Device with Fine Guidance Sensor 22

Figure 18: Space Telescope Servicing Tools - Development Models 23

Figure 19: Space Telescope EVA Ratchet Wrench 24

r, r Figure 20: Spacelab 1 European Bridge Structure 25

Figure 21: Spacelab 2 Pallets and Experiment Mockups 26

LIST OF TABLES

Table 1: Summary of Contract Modifications and Specific 5

End Items

Table 2: Assessment of Space Telescope EVA Design 27

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1.0 INTRODUCTION

1.1 PURPOSE OF CONTRACT

Since November 28, 1978, Essex Corporation has been under contract

to NASA's George C. Marshall Space Flight Center for the development of n'

a Space Telescope design development mockup for use in the MSFC Neutral

Buoyancy Simulator (NBS). Since the beginning of the contract, numerous

underwater tests have been performed with pressure—suited engineers and

astronauts to evaluate the crew tasks associated with both planned

instrument changeouts and unscheduled repairs. These tests have resulted

in flight hardware modifications and better definition of the crew

procedures. Throughout the contract, Essex' tasks have been consistent:

• Review flight hardware concepts and drawings

• Prepare mockup drawings

• Fabricate mockup hardware

• Support test operations.

Although the task titles have remained the same, the hardware produced

during the contract has varied considerably. The major hardware items

produced include the following:

'

•

Aft shroud — frame, skin, floor

CP Focal Plane Assembly — structure, guiderails, preload devices,

J latches, equipment shelf with star trackers (3)

• Scientific Instruments — axial and radial

Support Systems Module (SSM) Equipment Section — frame, skin,

doors

^- ^^ • Optical Telescope Assembly (OTA) Equipment Section

• Orbital Replacement Units for SSM & OTA equipment sections

• Light Shield — 18 ft.

• Solar Array

• Diode Box

• ORU Spares Carriers

• Crew Aids — handrails, foot restraints and sockets.

In addition to providing the above hardware, Essex also provided support

for the NBS tests in the form of test conductors, test observers,

3

hardware setup, hardware repairs and modifications during the test, and

^' test reports. Simulation test plans provided by Essex prior to the test

runs include the following:

' • NBS 33 — Rate Sensor Unit/Star Tracker Access Evaluation

r • NBS 34 — Axial ST Removal/Replacement

• NBS 35A — Evaluation of the Solar Array as in ORU

NBS 35B — Evaluation of the Solar Array Mechanisms. 

:everal contract modifications resulted in the performance of Space

Telescope mockup related tasks but actually had little to do with

development of the Space Telescope mockup hardware. These tasks include:

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0 Mod 2 - Development of an Advanced X•Ray Astrophysics Facility

Orbital Maintenance Plan

0 Mod 6 - Development of Tnree Spacelab-2 Pallets and Approximately 30 Experiment Mockups

o Mod 7 - Development of Approximately 40 Spacelab-1 Experiment

Mockups and European Bridge Structure.

The contract tasks, end products, results and conclusions are described

in the following sections.

1.2 CONTRACT HISTORY

The basic contract has been modified 11 times since its be innin g g .

These modifications have been to provide more mocku p hardware, revise

existing mockups as the flight design changed, provide maintenance

mission support equipment and provide related support to the Spacelab

and AXAF projects based on mockup fabrication techniques and on-orbit

servicing experience gained from the Space Telesccra experience.

I

A flow chart of contract modifications is presented as Figure 1 and

shoots the major end product for each modification.

2.0 TECHNICAL APPROACH

During the basic contract and modifications 1, 3, 4, 5, 8, 9, 10,

and 11, Essex performed the same generic tasks but for different parts

of the Space Telescope mockup. These tasks were:

Task A - Review Space Telescope Drawings

Task B - Prepare Mockup Drawings

Task C - Fabricate Mockups.

Although the mockup hardware produced during tFe performance of the

tasks varied considerably, the type of activities required to turn

flight drawings or concept sketches into mockup hardware remained fairly

constant. These tasks are described below.

2.1 TASK A - REVIEW SPACE TELESCOPE DRAWINGS

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During thi; task, Essex reviewed the available Space Telescope

drawings and concept sketches to serve as a basis for the mockup design

effort. Essex also identified any dimensions, equipment configurations

or interfaces not defined by the available drawings that were needed to

^w perform mockup design. After examination of these drawings and sketches,

Essex determined the functional requirements of each mockup component

and identified the fidelity requirements. During drawing review and

subsequent design, fabrication and testing activities, Essex had

frequent contact with Lockheed, Perkin-Elmer, and British Aerospace

Personnel to ensure that the latest hardware designs were duplicated on

the mockup hardware.

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NAS8-33272

Aft Shroud, Scientific

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^ Instruments, FGS, SMM

d Equipment Section

Mod 1 - Mod 2 -

Equip. Section, Solar {^ Lessons Learned

Array, Light Shield `3 for AXAF

Mods 3 & 4

Equipment Shelf

Mod 6 - Mod 5 - Mod 7 -

I SL-2 Pallets & (^ Test Plans SL-1 Experimdnt

Experiment Hardware ^r' "`333 Hardware

Mod 8, 9 & 10

9 Space Support Equipment

Mod 11 -

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ORU Spares Carrier

Figure 1: Space Telescope Contract History

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2.2 TASK B - PREPARE MOCKUP DRAWINGS

Essex then prepared detailed sketches of the Space Telescope mockup

hardware showing key dimensions and illustrating the configuration and

fidelity of all mockup components. These sketches were then provided to

the COR for review and approval before p reparation of the detailed

engineering drawings.

After approval of the configuration sketches, Essex developed the

mockup drawings. All mockup drawings specified materials and finishes

compatible with the neutral buoyancy environment and specified edge and

corner requirements to prevent injury to pressure suited crewmen and

support divers.

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s 2.3 TASK C - FABRICATE MOCKUPS

After COR approval, Essex released the drawings to the Essex shop.

During mockup assembly all mockup components were available to NASA

personnel for inspection. As the mockups were completed, they were

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examined by Essex designers for compatibility with the drawing requirements including materials and finishes, dimensions, tolerances, and

equipment interface provisions.

After approval of the hardware in the Essex shop by the COR, the

mockups were delivered to the MSFC NBS through Building 4471, Shipping

and Receiving, along with appropriate shippi- g labels and copies of Form

DD 250.

3.0 END ITEM DESCRIPTION

a The contract end items are listed in Table 1 and include all

hardware and reports prepared for Space Telescope, AXAF and Spacelab.

These items are described in the following paragraphs.

3.1 SPACE TELESCOPE

The Space Telescope-relatated deliverables include the neutral

buoyancy mock- , p, space support equipment and test plans.

3.1.1 Space Telescope Mockup

Figures 2 and 3 show the as-built mockup configuration and the

major mockup components. The mockup was fabricated in sections and

assembled in the NBS by Essex and MSFC divers. All components weight

less than the 1800 lb overhead crane limit and are less than 12 ft. tall

to pass over the tank walkway at the highest crane hook height.

The major mockup sections are the a£ shroud (2 sections), focal

$^ plane assembly, Space Support Module (SSM) equipment section, optical

a telescope assembly (OTA) equipment section, and might shield (3

sections). Other equipment such as the solar array, magnetic torques

and orbital replacement units (ORUs) were attached to these major

4 sections before or after assembly of the mockup in the NBS.

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And Specific End Items

TECHNICAL CONTRACT

ACTIVITY MODIFICATION SPECIFIC END ITEM

Space Basic Contract Aft Shroud and Focal Place Assembly

Telescope Alignment Devices, Guiderails

Mockups Preload Devices & Latches

Scientific Inutruments (3)

M Fine Guidance Sensor Handrails

Foot Restraint Sockets

` S.MM Equipment Section

ORUs for SMM

Equipment, Shelf, Star Trackers and

RSUs ( 2 configurations)

Mod 1 OTA Equipment Section

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;Light Shield - 18 ft.

Solar Array

Diode Box

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Mod 3, 4 New Equipment Shelf & 3 Star

Trackers and RSUs

Mod 5 NBS Test Plans

Mod 8, 9 ORS Transfer Device

° ORU Spares Carrier

Spacelab Pallet

Foot Restraints

SSM Handrails & Cables

Flight Support System

Faint Object Camara

Axial SI Rails ( 2 sets)

Bay 10 ORUs

Keel & Trunnion Fittings

! OTA Equipment Section, one High

Fidelity Bay

Updated Equipment Shelf & Star

Trackers (3)

Light Shield Fings, Handrails

Magnetic Torquers (4)

RMS Grapple Fixture

Upgraded Fine Guidance Sensors (2)

Light Shield Flotation

Upgraded Solar Array

New Flight Configuration Hi

Fidelity Diode Box

g I Mod 10, 11 ORU Spares Carrier Modifications

i Crew Aids

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Flotation/Support Structures

Advanced X-Ray Mod 2 AXAF Orbital Maintenance Plan -

Astrophysics Preliminary

f>,^ Facility

^ F Spacelab - 2 Mod 6 Three Spacelab Pallets

30 Experiment Mockups

{ Spacelab - 1 Mod 7 40 Experiment Mockups

B European Bridge Structure

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High Gain Antenna

Not Provided

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gneti.c Torquers (3

Array Mount

ode Box

Axial Scientific

nstruments (3 prov

1It End Equipment 

Provided

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Star Trackers/

Equipment Shelf

Figure 2: ST Mockup Configuration

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Figure 3: SI).,(. 'fc, les,ope NliS Mockup

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The aft shroud focal plane assembly and attached ORU latches and

insertion guiderails were built to flight hardware accuracy requirements

and were used for one-G insertion/runo, ,nl tests.

The major mockup sections and attachment hardware are shown in

Figures 4 through 12.

In addition to the Space Telescope mockup, Essex also provided a

Flight Support System (FSS) cradle and berthing platform (Figures 13 and

14) for positioning the telescope during servicing. This FSS was Cradle

E A' developed for the Multimission Modular Spacecraft servicing and

return operations.

Essex also developed an ORU spares carrier which consists of a

Spacelab pallet, ORU stowage racks, an environmental enclosure, an

overhead rail system and an ORU transfer device. Figures 15, 16 and 17

show the spares carrier and its major components.

3.1.2 Space Support Equipment

r ` Throughout the contract Essex developed tools for ORU changeout and

^. manual override of EVA mechanisms. Several of the ratchet wrenches are

shown in Figure 18. The last EVA ratchet wrench developed for ST

servicing is shown in Figure 19. This wrench has a tether ring for

r attachment to the EMU suit tether, a palm wheel for use with the glove,

m< a 39rge cross-section handle for easier gripping, and a ball detent with

r button release for securing the socket or extension to the 3/8

(n. arrive.

Since this wrench was fabricated, Essex designed and fabricated two

flight wrenches and a trainer for STS-5. Essex also modified the ball

detent locking feature for a *.wrench provided to iSC to produce a more

positive locking feature. Both tasks resulted in design and material

changes that should be incorporated into the flight ST servicing

wrenches.

Essex also provided EVA Foot restraints and attachment sockets for

the servicing workstation.

3.1.3 Test Plans

Several test plans were prepared as part of the contract

modification No. 5. These plans include:

• NB-33 Rate Sensor Unit/Star Tracker Access Reevaluation

• NB-35A Evaluation of a Solar Array as an ORU

e NB-35B Evaluation of Solar Array Mechanisms

• Determine Space Telescope Crew Restraint Locations

• Evaluate SI Latch/Preload Crew Tasks and Restraint Locatons

• Verify Radial SI and Wide Field Planetary Camera

Insertion/Removal Forces and Clearances.

During each NBS test, Essex provided test support in the form of

test conductors, utility divers and real-time hardware modifications.

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Figure 10: Equipment Section ORU Changeout

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Figure 13: Fliplit Support System Cradle

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Figure 14: FSS Berthing Ring

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Figure 15: OR11 Spares Carrier and Transfer Device

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Figure 16: Spares Carrier - View from Space Telescope:

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Figmre 17: Transfer Dvvict , with Find Guidance Sensor

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Figure 18: Space Telescope Servicing Tools -

Development Models

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Figure 19

Space Telescope EVA Ratchet Wrench

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I T

ID 3.2 SPACELAb

As a result of Modification No. 6 and 7, Essex used design and

} fabrication techniques developed for ST mockup development for

production of Spacelab (SL) -1 and -2 pallet and experiment mockups.

3.2.1 Spacelab-1

Essex designed and fabricated the European .Bridge Structure (EBS)

mockup and the associated experiment hardware. This mockup is shown in

Figure 20.

3.2.2 Spacelab-2

The three pallets and most of the experiment hardware were produced

and assembled into the SL-2 configuration (Figure 21), Verification

flight instrumentation (VFI) was also provided. Electrical connector

mockups were provided on all experiments and VFI. The mockup is

.° currently being used to develop flight electrical cable harnesses.

3.3 ADVANCED X-RAY ASTROPHYSICS FACILITY (AXAF)

As a result of knowledge gained in performance of the basic ST

v contract and participation in the NBS tests, Essex developed a

preliminary servicing plan for AXAF. This plan utilized but improved on

existing ST servicing hardware and crew aids.

4.0 TEST OBSERVATIONS

+ Based on observations made during the Space Telescope NBS test

series, it appears that the planned, unscheduled and contingency EVA

tasks on Space Telescope are difficult for the crew members to perform.

This is evidenced by the test experience which has shown that some of

the planned and contingency tasks are very time consuming, are fatiguing

to the crew, produce excessive glove wear during tool use, and require

many foot restraint locations. The simulations have also demonstrated

that the instruments can be jammed on the insertion rails, and are

sometimes handled using instrument components not designed for crew

interface. These ptoblems are attributable somewhat to the size and

1 mass of the instruments since they are large compared to the hardware

handled by the crews during previous EVA's.

A second factor contributing to the ;p roblem is difficulty in

complying with the existing EVA design standards. The eesign standards

that apply to the Space Telescope servicing hardware include:

MSFC-STD 512, Man/System Design Criteria for Manned Orbiting Payloads

MSFC-STD 512A, Man/System Requirements for Weightless Environments

JSC-10615, Shuttle EVA Description and Design Criteria.

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EU

During a normal spacecraft development program, the program managers and

designers would use these standards to identify human engineering design

goals and specific design requirements. Table 2 lists sonic of the key

design requirements that should be considered. As the spacecraft is

developed and formal reviews are held, design standard violations should

be identified per established RID procedures and resolved by equipment

redesign, operational work arounds, or waivers.

Some of the difficulties of the planned and unscheduled EVA

tasks could possibly have been prevented if these design requirements

had been implemented prior to the NBS test series. For future Space

Telescope neutral buoyancy tests it is recommended that the hardware and

procedures be reviewed for compliance with the EVA design criteria and

any discrepancies be resolved prior to testing. This would maximize the

benefit of the test activity and reduce the time and cost of learning

the same EVA lessons learned during past projects such as Skylab. Tt is

u also recommended that EVA crew interfaces be verified through one-G

testing at MSFC and through early NBS testing prior to establishing

baseline equipment designs that are difficult to change.

28
{ lab.le 2 - Applicable EVA Design Requirements

' PARAGRAPH NO.

x MSFC MSFC JSC

512 512A 10615 DESIGN REQUIREMENT

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3.2.2 4.4 Pip pins - Criticality of alignment is undesirable.

Use as a launch lock is acceptable. Other fasteners

are more desirable. No EVA use is recommended.

a 4.1.2 EVA tasks should bperformed by one crewman w/another

EVA crewman observing & tending tethers.

! 4.1.3 3.3.9 Tasks that depend on dexterity and tactile feedback

i

should be avoided.

4.1.4 3.3.9 Tool actuation force of 10 lbs is desired, 20 lbs

p' maximum.

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4.1.7 3.4 Exposed edges should have .06 in. radius or be

3 guarded.

" 4.1.8 Portable foot restraints should be installed w/ one

hand. Adjustments should be accomplished w/ one

+ hand.

3

4.2.1 Premounted foot restraints will be used at all

nominal worksites, contingency worksites may use crew

installed restraints.

4.2.2 For replaceable modules all forward edges should be

visible during alignment & attachment.

4.2.2 Hardware should require a push/pull force less than

35 lbs to install & remove.

4.2.2 3.3.10 Mechanical flag or status light shall be used to

indicate removal or installation of a component.

4.2.2 The preferred screw type fastener is the internal hex

n head screw.

29