National Aeronautics and Space Administration

TECHNICAL UPDATE 2007

NASA ENGINEERING & SAFETY CENTER

NESC

Stakeholder Messages .......................... 2

Leadership Team Introduction ................ 3 

NESC Overview ..................................... 4

NASA Technical Fellows ......................... 7

Technical Highlights .............................. 10

NESC Highlights from the Centers:

Ames Research Center ................... 31

Dryden Flight Research Center ....... 32

Glenn Research Center ................... 33

Goddard Space Flight Center .......... 34

Jet Propulsion Laboratory ............... 35

Johnson Space Center ................... 36 

Kennedy Space Center ................... 37

Langley Research Center ................ 38

Marshall Space Flight Center .......... 39

Stennis Space Center ..................... 40

White Sands Test Facility ................ 41

NESC Honor Awards .............................. 42

Biographies .......................................... 44

NESC Alumni ........................................ 48

Featured Technical Paper ...................... 49

Recent NESC Publications ..................... 63

Lunar dust grain surface etched by 

solar wind; such surfaces have a 

high density of crystal dislocations 

and are presumably very reactive. 

The NESC held a workshop on 

lunar dust to bring together the 

scientific and engineering communities to discuss the known 

hazards of lunar dust on humans 

and mechanical systems.

Strategies to mitigate the effects of 

lunar dust on our next generation 

of explorers will be needed to

enable a permanent return to

the lunar surface.

X14,000 1 m

NASA
4 NESC 2007 TECHNICAL UPDATE

STAKEHOLDER MESSAGES

Bryan O’Connor NASA Chief Safety and Mission Assurance Officer

In its fourth year, the NESC has shed all of its new-guy-on-the-block image of the past. It is clearly a recognized agency asset, one that people are deferring to and depending upon. People in the programs and institutions no longer need to be reminded of the existence of the NESC, they know it’s there, and to a greater degree 

than ever, they are leaning on the NESC for help on the Agency’s toughest issues. In addition, at the request 

of the NASA Administrator, we are now establishing a NASA Safety Center in Cleveland. The NSC will lead 

technical excellence initiatives for Safety and Mission Assurance. Key to the success of the NASA Safety Center will be close coordination with NESC on their assessments and technical excellence work.

“The NESC is an exemplary model for rapidly, effectively and proactively applying the best talent we have to the toughest and most 

urgent operational challenges at NASA. In doing so, the NESC continues to gain recognition as a steward of technical excellence and as 

an invaluable resource to the Agency’s highest priority programs.”

— Dr. Michael D. Griffin, NASA Administrator

Christopher J. Scolese Associate Administrator

We at NASA are fortunate to be at the forefront of efforts to explore and utilize the air and space environment 

for the benefit of civilization. Our missions range from improving air traffic control, to tracking forest fires 

from UAVs and spacecraft, to sending humans into space, to understanding the Earth, to robotic missions 

at other planets, to observing and understanding our Universe. The NASA Engineering and Safety Center 

continues to be a valuable resource for all of these NASA missions and even for other Agencies. This year the 

NESC became the home institution for our NASA Technical Fellows. These individuals represent the best individuals in their technical field. They are capable of advancing the field through their leadership, training the 

next generation of leaders in their field, guiding the agencies activities in their specialty, building teams to solve 

the most difficult problems we face, and representing NASA to the broader aerospace community in the USA 

and internationally. NESC was the logical home for our Technical Fellows because it already has the broad 

NASA perspective and already engages our entire technical and project communities. A sign of effectiveness 

is the degree to which other organizations ask for your services. Given this metric the NESC is probably one 

of the most effective organizations around. It continually receives requests from NASA and other agencies to 

solve problems that require the use of skills or facilities not readily available to a single institution. The NESC 

continues to be effective at doing this and most importantly they accomplish their tasks in an inclusive and 

collegial manner. In closing, the NESC continues to demonstrate its value to NASA by solving some of the 

most difficult problems we face and in the future will serve to further enhance our technical excellence through 

the leadership of the technical fellows.
NESC 2007 TECHNICAL UPDATE NESC 2007 TECHNICAL UPDATE 5

LEADERSHIP TEAM INTRODUCTION

STAKEHOLDER MESSAGES

The fourth year of operation brought about a number of 

changes as the organization evolved to meet the needs of 

the Agency — while remaining true to our core mission 

of providing value-added independent assessments, testing and 

analyses in support of the Agency’s high-risk programs and projects. This year, we have seen a marked increase in support to the 

Exploration Systems Mission Directorate and have undertaken 

a number of proactive assessments to generate new knowledge, 

expertise and data that can be used by the Constellation Program 

in making critical design decisions in the future. We have continued to provide support to the Space Shuttle and International 

Space Station Programs, often engaging in real-time mission 

critical decisions. In addition, we have also contributed to the 

Science Mission Directorate through our participation with the 

Dawn, Phoenix and SOPHIA Missions. In all of these activities, 

our strength remains our ability to bring together diverse teams 

of technical experts from across NASA, industry and academia in 

our pursuit of engineering excellence. The NESC is also working 

closely with our partner organization, the NASA Safety Center, 

to provide the Agency with a robust technical and mission assurance resource to address the most critical, high-risk problems. In 

April of the year, the existing twelve NESC Discipline Experts 

were transitioned to NASA Technical Fellows. An additional seven NASA Technical Fellows will be added to the NESC over the 

next few years. The NASA Technical Fellows have been charged 

with providing technical leadership and stewardship of their disciplines and to proactively address their discipline’s most urgent 

issues. A number of these discipline advancing activities are described in this Technical Update. Again this year, our Technical 

Update will highlight our accomplishments, broadly applicable 

lessons learned, Center contributions, and NESC Honor Award 

recipients. The NESC Leadership Team is pleased to provide 

you with this Technical Update for 2007 as we look forward to 

our fifth year of operation. 

Dr. Michael Ryschkewitsch NASA Chief Engineer

While I am new to the job of Chief Engineer, the NESC is one part of the activities of the Office of the Chief 

Engineer with which I am very familiar. I was part of the original team asked to “stand-up” the NESC. Over 

the ensuing years, the NESC has fulfilled its promise and more. A very strong leadership team and a superb 

staff have demonstrated the value of the NESC. The term “One-NASA” applies and NESC has again and 

again assembled the best talent from across NASA to attack the most critical problems and had tremendous 

impact on everything from earth observations to astrophysics missions to planetary missions to shuttle safety 

to ISS operations to preparing for the future of humans in space. It is hard to think of a tough problem with 

which the NESC and its people have not been involved and had a major positive impact. Perhaps as importantly, the alumni of the NESC have gone on to some of the most important jobs in the Agency, a recognition 

both of their talent and the value of the NASA-wide experience base they acquired in their NESC work. I look 

forward to working even more closely with the NESC team than I have in the recent past and to supporting its 

mission as we go forward into a bright future with lots and lots of engineering challenges ahead of us.

(Back row from left) Kenneth Cameron – Deputy Director for Safety, Patricia Dunnington – Manager of the Management and Technical Support Office, Dawn Schaible 

– Manager of the Systems Engineering Office, Dr. Charles Camarda – Deputy Director 

for Advanced Projects. (Front row from left) Ralph Roe, Jr. – Director, Timmy Wilson 

– Deputy Director.

NESC
6 NESC 2007 TECHNICAL UPDATE

Improving Safety Through Engineering Excellence 

NASA’s unique and extraordinary achievements have only been realized after committing to endeavors that have a substantial 

component of risk. The role of the NASA 

Engineering and Safety Center (NESC) is to 

identify and mitigate that risk and maximize 

safety by taking advantage of one of NASA’s 

strengths — engineering excellence. Formed 

in the wake of the Columbia accident, the 

NESC has grown into an important and respected organization by following the strategy that the path to mission success is safety, 

and safety is achieved through engineering 

excellence. 

The NESC is a unique resource, which helps 

solve challenging technical issues and proactively works to prevent problems from occurring. The independent nature of the NESC 

allows it to address issues as an objective 

voice—separate from the Agency’s programs 

and projects. The NESC exploits the depth 

of knowledge within the Agency by tapping 

into the far-reaching talent pool at NASA, 

and further increases that range by engaging 

with other Government agencies, industry, 

and academia. Organized into NESC Technical Discipline Teams (TDTs), there is always a ready pool of engineers and scientists 

from 15 separate disciplines. But the breadth 

of experience in the NESC is equally important. The vast background and experience 

base is leveraged through the NESC Review 

Board (NRB), ensuring all results, recommendations and decisions are sound and supported with technical justification (pictured 

above right).

NESC Mission

The NESC carries out its mission in a variety of ways. The formal, structured activities 

that are pursued by the NESC are called assessments. They can be either in response to 

a request or generated from within the NESC 

as a directed or discipline enhancing task. 

The level of participation from the NESC in 

an assessment can range from the furnishing 

of expertise for consultation to a completely 

independent investigation with testing, modeling, and analysis. Because the NESC has 

the ties to a vast human knowledge base, 

experts can be easily found to participate in 

NESC assessments as well as other activities such as mishap investigations, technical 

reviews, and program-sponsored tiger teams. 

Furthermore, because the NESC is an Agency resource, it is a leader for Agency-wide initiatives, standards, and working groups such 

as the Data Mining and Trending Working 

Group. The NESC has also begun issuing 

technical bulletins. These are concise articles 

distributed NASA-wide illuminating a specific problem or concern that has been addressed or discovered by the NESC and may 

be relevant to NASA programs. 

The NESC is also well-suited to provide the 

organizational structure for large, non-NESC 

initiatives that require assembling a large 

team of personnel with a wide variety of skills 

and located across multiple locations. An example of this is the Crew Exploration Vehicle 

(CEV) Smart Buyer Design Team, which designed an alternative proposal for the CEV 

(later renamed Orion) using a widely distributed network of NASA engineers

 The structure of the NESC is geared toward maintaining a diverse and broad base of 

knowledge, keeping informed and engaged 

with each Center and the Agency’s major 

programs, responding efficiently to requests 

for assistance, and retaining a high degree 

of independence. Leadership of the NESC 

is provided by the Director’s Office, which, 

with the Director and Deputy, includes the 

Deputy Director for Safety, Deputy Director for Advanced Projects, Chief Astronaut, 

and Chief Scientist. The discipline-specific 

technical teams of readily available experts, 

the TDTs, are drawn on to address technical 

issues as they arise. All but three of the TDTs 

are led by the NASA Technical Fellows. The 

exceptions are the Human Space Flight Operations TDT, led by the NESC Chief Astronaut; the Robotic Missions TDT, led by 

Great deeds are usually wrought at great risks. — Herodotus

N E S C O V E R V I E W 

The NESC Leadership Team meets regularly as the NESC Review Board (NRB) to review all engineering reports 

prior to their publication. The NRB peer review process is a critical step for maintaining engineering excellence 

in NESC products. 

NESC

NESC
NESC 2007 TECHNICAL UPDATE 7

N E S C O V E R V I E W 

Space 

Operations

53 %

Aeronautics 

Research

1 % External

1 % General (across 

multiple mission

directorates)

11 %

Exploration

Systems

19 %

Science

15 %

NASA 

77 %

Industry

18 %

University

4 %

Other U.S. Gov.

1 %

Program Analysis 

& Evaluation <1%

Anonymous <1%

Safety Mission 

Assurance at Centers 4%

External to Agency 6%

Program

Management 

17%

NESC 

30%

Engineering &

Scientific Organizations 

32%

Office of Safety and 

Mission Assurance 4%

Office of Chief Engineer 3%

Center Management 3%

 

Space 

Operations

53 %

Aeronautics 

Research

1 % External

1 % General (across 

multiple mission

directorates)

11 %

Exploration

Systems

19 %

Science

15 %

NASA 

77 %

Industry

18 %

University

4 %

Other U.S. Gov.

1 %

Program Analysis 

& Evaluation <1%

Anonymous <1%

Safety Mission 

Assurance at Centers 4%

External to Agency 6%

Program

Management 

17%

NESC 

30%

Engineering &

Scientific Organizations 

32%

Office of Safety and 

Mission Assurance 4%

Office of Chief Engineer 3%

Center Management 3%

 

the NESC Chief Scientist; and the Systems 

Engineering TDT, led by the Manager of the 

NESC Systems Engineering Office. To help 

coordinate the facilities and resources of each 

Center when required to support NESC assessments, each Center (including Headquarters) has a resident NESC Chief Engineer 

(NCE), a role fulfilled at some Centers by the 

Center Chief Engineer. The Chief Engineers 

are engaged with their Center’s activities and 

provide insight into the programs and projects that impact their Centers. 

The Principal Engineers (PE) have the primary responsibility of leading assessments — 

especially when the assessment has a broad 

scope and encompasses more than one discipline area. Some assessments with a more 

focused scope may be led by Technical Fellows or NCEs. The NESC also has a Systems 

Engineering Office (SEO), which performs a 

variety of functions such as dispositioning requests as they come in, performing proactive 

trending analysis and problem identification, 

and providing NESC support for Agencywide initiatives and working groups. The 

business responsibilities of the NESC belong 

to the Management and Technical Support 

Office (MTSO), which attends to the contracting, budgeting, and management of the 

NESC’s infrastructure. 

These elements come together to form the 

heart of the NESC — the NESC Review 

Board. The life cycle of every formal activity performed by the NESC requires approval 

of the NRB. The NRB brings a diversity of 

thought to the decision-making process as it 

is an amalgam of experts representing different Centers, programs, and engineering 

backgrounds. 

People

More than just a unique, independent organization unto itself, the NESC is a model 

framework for finding and taking full advantage of expertise available within NASA. The 

majority of technical positions within the 

NESC are temporary. This allows the employees to take their experiences and lessons 

learned back to their home Centers and organizations. And while there are approximately 

60 NESC-badged employees, there are 10 

times that many people who participate in 

NESC activities through the TDTs. These 

matrixed employees are from every Center 

and Headquarters and enjoy the benefits of 

working with and learning from their colleagues and the leaders in their fields.

Independent Objectivity

One of the defining characteristics of the 

NESC is its independence. The NESC is 

funded through the NASA Office of the Chief 

Engineer, so it is not in line with any program, 

project, or mission directorate either from a 

budgetary or organizational standpoint. In 

addition, the NESC has from its inception 

been closely aligned with the NASA Office 

of Safety and Mission Assurance (OSMA). 

All of NASA is encouraged to call upon the 

NESC and requests for NESC support are 

received from many sources: Agency senior 

management, program and project managers, NASA engineers and scientists, even the 

general public. The pie chart (shown at right)

depicts the sources of requests that have been 

accepted for implementation as assessments. 

2007 Technical Discipline

Team Composition

Source of Accepted

Requests: 223 Total 

Accepted Requests by Mission 

Directorate: 223 Total 

2007 Metrics Summary

(As of Nov. ’07)

n Accepted Requests for Assistance.......... 55

n Technical Assessments (Detailed

independent analysis and test) .................. 33

n Technical Support to Project Teams....... 18

n Special Studies.........................................4

Continued on next page
8 NESC 2007 TECHNICAL UPDATE

A formalized process has been instituted to

address each request submitted to the NESC. 

Initially, each request received is vetted by 

the SEO, and then those that are approved 

by the NESC leadership are assigned a lead. 

The lead will act as a project manager and 

guide the assessment from the development 

of a plan through the completion of the final report. The results of each assessment are 

solution-driven preventative and corrective 

recommendations that are presented to the 

NESC Leadership Team and stakeholders of 

the assessment. The NESC strives to set the 

example for the Agency by providing full and 

readily applicable engineering reports for every activity. Along with each report, lessons 

learned are communicated to Agency leadership and to engineers through avenues such 

as NASA’s lessons learned system and this 

Technical Update. 

Partnerships 

One of the keys to maintaining the effectiveness of the NESC is its capacity to build and 

nurture the partnerships that are vital to 

reach in-depth expertise, expand the range of 

available resources, and utilize the focused experience and skills that outside organizations 

have to offer. The MTSO ensures for the 

NESC that a broad set of contract vendors 

are in place and are readily accessible when 

needed. The NESC has formed working relationships with other government agencies 

such as the Federal Aviation Administration 

and the Navy and Marine Corps School of 

Aviation Safety. The NESC formed a partnership with the National Transportation Safety 

Board (NTSB) to provide NESC technical 

personnel formal training on managing or 

serving on mishap investigations. From this 

partnership, the NESC has gained immeasurable knowledge from NTSB investigators on 

how they solve some of the most challenging 

aviation mishaps and accidents.

The NESC has also enlisted the resources 

of national laboratories and independent 

research organizations such as Sandia and 

Lawrence Livermore National Laboratories, 

Southwest Research Institute, and the National Institute of Aerospace. Some of the 

partners from industry include: Alliant Techsystems, Boeing, Janicki Industries, Lockheed 

Martin, and The Aerospace Corporation. 

Within NASA, one of the NESC’s developing 

partnerships is with the newly-formed NASA 

Safety Center (NSC)—an organization that 

has been created based on the NESC model 

to foster safety and mission success within the 

Agency in technical areas not directly within 

the scope of the NESC. The NSC will support the NESC (and other organizations) in 

disciplines including system safety, reliability and maintainability, quality engineering, 

software assurance, range safety, operational 

safety and aviation safety. 

N E S C O V E R V I E W 

Available to anyone that 

 needs independent testing, 

analysis, or assessment of 

NASA’s projects, the NESC can 

be reached through the NESC 

Chief Engineer at each Center 

or by email at nesc@nasa.gov. 

More contact information is 

available from the NESC website: 

www.nesc.nasa.gov. 

Continued from previous page

NESC

Members of the NESC

Composite Crew Module 

(CCM) Team provide NESC 

Review Board members

with a periodic update.

Mr. Michael Kirsch (far right)

is a NESC Principal Engineer 

(PE) and CCM Project 

Manager. To his right is Mr. 

Paul Roberts, back-up NESC 

PE and Dr. Sotirios Kellas, 

Test and Verification lead 

for the CCM Team. (Far left)

is Dr. Ivatury Raju, NESC 

Review Board member and 

NASA Technical Fellow for 

Structures.
NESC 2007 TECHNICAL UPDATE 9

T E C H N I C A L F E L L O W S 

As its fundamental mission, the NESC 

strives to set the example for engineering 

and technical excellence within NASA. The 

NASA Technical Fellows, and their Technical Discipline Teams (TDTs), provide the 

collective knowledge base that enables the 

NESC to perform its primary service to the 

Agency of independent test, analysis and 

evaluation of NASA’s most difficult problems. The Technical Fellows and their TDT 

members are specialists in diverse engineering disciplines pulled from the ten NASA 

Centers and from partner organizations external to the Agency.

Inspired by the overall success of the NESC 

organization, the 12 existing NESC Discipline Experts were named as the first NASA 

Technical Fellows, and recognized in a ceremony in Hampton, Virginia on April 11, 

2007. The NASA Technical Fellows Program 

was established to provide leadership, stewardship, and role models for NASA discipline 

engineering communities, increase the focus 

on technical excellence Agency-wide, and 

provide technical consistency across NASA 

as members of the NESC in support of the 

Office of the Chief Engineer. Consistent 

with NESC practice, the Technical Fellows 

will remain resident and actively engaged at 

their respective NASA Centers. 

NASA Technical Fellows are competitively 

selected using the Agency’s ST (Scientific or 

Professional) criteria. The Technical Fellows 

include the following disciplines, patterned 

after the disciplines defined by the NESC: 

Guidance, Navigation and Control (GN&C); 

Nondestructive Evaluation (NDE); Propulsion; Avionics; Loads and Dynamics; Aerosciences; Mechanical Systems; Human Factors; 

Materials; Structures; Life Support/Active 

Thermal; and Software. Plans over the next 

several years include adding Space Environments, Electrical Power, Flight Mechanics, 

Passive Thermal, Cryogenics, Sensors/Instrumentation, and Systems Engineering 

to the list of Technical Fellows’ disciplines. 

The need for additional disciplines will be 

evaluated semi-annually and reviewed by the 

Agency’s Engineering Management Board.

The primary roles of the NASA Technical 

Fellows are to assemble, maintain and provide leadership for the TDTs and act as the 

stewards for their disciplines through workshops, conferences and discipline advancing 

activities. The Technical Fellows serve as the 

senior technical experts for the Agency. Some 

Technical Fellows may also lead Agency-wide 

working groups. The Technical Fellows are 

an independent resource to the Agency and 

industry to resolve complex issues in their respective discipline areas. They also coordinate 

Agency Leadership Appoints First NASA Technical Fellows

Continued on next page

NESC

(Above) NASA and NESC Leadership recognize the new NASA Technical Fellows – (From left) Ralph Roe Jr. 

– NESC Director, George Hopson – Propulsion, Mitchell Davis – Avionics, Cornelius Dennehy – Guidance, Navigation and Control, John McManamen – Mechanical Systems (former), Dr. David Schuster – Aerosciences, Henry 

Rotter – Life Support/Active Thermal, Dr. Curtis Larsen – Loads and Dynamics, Dr. William Prosser – Nondestructive Evaluation, Dr. Ivatury Raju – Structures, Dr. Robert Piascik – Materials, Dr. Cynthia Null – Human Factors, 

Michael Aguilar – Software, Timmy Wilson – NESC Deputy Director and Christopher Scolese – NASA Associate 

Administrator, former NASA Chief Engineer.
10 NESC 2007 TECHNICAL UPDATE

T E C H N I C A L F E L L O W S 

CIBER

Another important function of the NASA 

Technical Fellows Program is the NESC 

Academy. 

The NESC Academy was established to ensure that the vast body of knowledge of the 

NESC’s scientists and engineers remains viable and accessible to the current community 

of NASA professionals. The NESC Academy 

provides a forum through which this knowledge can be passed on to NASA’s younger 

generation. Each Technical Fellow has, or 

will be, given the opportunity to deliver an 

Academy class focusing on their discipline. 

During the past year, the NESC Academy 

delivered courses in Materials Durability, 

Human Factors and Software Engineering.

Materials Durability 

Understanding materials durability is critical to NASA’s mission and to explore this, 

the NESC Academy class entitled, “Materials Durability: Learning from the Past and 

Looking to the Future”, was offered July 

30 – August 2, 2007 in Houston, Texas at 

the University of Houston, Clearlake. Dr. 

Robert S. Piascik, NASA Technical Fellow 

for Materials, and Dr. William H. Prosser, 

NASA Technical Fellow for Nondestructive 

Evaluation (NDE), and their colleagues from 

both of their TDTs, worked jointly on this 

effort. This course focused on understanding 

material damage modes as they relate to materials-environment interactions. Members 

of the Materials Technical Discipline Team 

shared their lessons learned as they related 

degradation mechanisms and described how 

analysis methods are used for assessing materials durability. 

“ This course has been excellent. 

It has given me an opportunity 

to meet with experts all across the 

Agency, academia, and industry.” 

Nate Green

Marshall Space Flight Center 

with each Center’s NESC Chief Engineer in 

the identification of potential discipline-related issues to be addressed proactively by 

the NESC. Other responsibilities include 

ensuring consistency between Agency-level 

standards and specifications and promoting 

the identification and incorporation of lessons learned into Agency processes. 

Collectively, the TDTs form a deep technical 

resource that supports NESC independent 

assessment teams. Typically, the Technical 

Fellows and their TDTs work together to 

define the discipline-specific resources (e.g., 

subject matter experts, tools, and test facilities) required to support assessment teams 

and other NESC activities. Members of the 

TDTs may fulfill those requirements, or the 

identified resources may be drawn from the 

various NASA Centers or from partner organizations. The Technical Fellows ensure 

that their TDTs are cognizant of all assessments that require the support of their disciplines, and they manage and coordinate 

discipline-specific resources required to 

support the NESC stakeholders.

 Communications between the Technical 

Fellows and their TDTs is accomplished 

via periodic teleconference meetings and 

with annual face-to-face meetings, and the 

NASA community is apprised of the yearly 

activities of the TDTs when the Technical 

Fellows provide an annual State of the Discipline address to the NASA Engineering 

Management Board and other Agency leaders. By drawing on the minds of the Technical Fellows and their TDTs, the NESC 

consistently solves technical problems, 

deepens its knowledge base, strengthens 

its technical capabilities, and broadens its 

perspectives, thereby further executing its 

commitment to engineering excellence. 

Continued from previous page..

The NESC Academy: Learning From 

the Past, Looking to the Future

By drawing on the minds 

of the Technical Fellows 

and their TDTs, the NESC 

consistently solves technical 

problems, deepens its 

knowledge base, strengthens 

its technical capabilities, and 

broadens its perspectives ... NASA Technical Fellow for Materials, Dr. Robert Piascik holds a side discussion during the NESC’s Academy 

course on Materials Durability. 
NESC 2007 TECHNICAL UPDATE 11

TECHNICAL FELLOWS

Human Factors

“...I was also interested in seeing 

how this applies to everything that 

we do everyday. I think its very exciting ...” 

Linda Patterson

Johnson Space Center

The NESC Academy’s fifth knowledge-capture course, “Human Factors: Learning from 

the Past and Looking to the Future” with Dr. 

Cynthia H. Null and colleagues, took place 

from December 5-7, 2006 at George Mason University. Dr. Null, the NASA Technical Fellow for Human Factors, assembled 

a diverse team of experts in the field of human factors. Topics included human characteristics and capabilities, development of 

in-space systems, engineering new systems, 

maintenance and manufacturing, and lessons 

learned from mishap investigations. 

Software Engineering

George Mason University also served as the 

location for the NESC Academy class on Software Engineering. “Software Engineering: 

Learning from the Past and Looking to the 

Future” was held from March 13-15, 2007. 

Michael L. Aguilar, NASA Technical Fellow 

for Software, led the instruction and course 

content that included the history of software 

engineering and the development and application of CAD and CAM and CASE tools, 

Unified Modeling Language (UML), and 

state charts. Mr. Aguilar discussed NASA’s 

software quality assurance program and lessons learned from space missions, and provided insight into newer software programs. 

Class activities included viewing a documentary on software engineering that showcased 

the applications of software in the design and 

manufacture of Boeing Aircraft’s B-777, and

a moderated discussion among seven guest

speakers and students that sparked thoughtprovoking questions and debate. 

“I found this class extremely helpful. I’ve been struggling with implementing the new NASA NPR 

software standards at my Center.” 

Stephen Jensen

Dryden Flight Research Center 

NASA Technical Fellow for Software, Michael Aguilar, and students discuss details of software engineering during 

the NESC Academy course.

■ Active Thermal Contro

and Life Support Systems

led by Hank Rotter at the

University of Houston

■ Space Propulsion Systems

led by George Hopson at 

Alabama A&M University

■ Power and Avionics le

by Robert Kichak at the

University of Maryland

■ Satellite Attitude Control

Systems led by Neil Dennehy 

at the University of Maryland

■ Human Factors led by

Cynthia Null at George

Mason University

■ Software as a

Engineering Discipline led

by Michael Aguilar at

George Mason University

■ Materials Durability 

Understanding Damage

Modes led by Robert Piascik

at the University of Houston

Past NESC Academy classes available online

More information on the NESC Academy, 

including available classroom and on-line 

courses is available on our website at:

http://www.nescacademy.org.

CIBER
12 NESC 2007 TECHNICAL UPDATE

TECHNICAL HIGHLIGHTS

SPACE OPERATIONS

While anchored to the foot restraint on Canadarm2, astronaut Dave Williams helps relocate a 600-pound Control

Moment Gyroscope (CMG) during STS-118 in August, 

2007. The NESC has been involved in determining the root 

cause of a previous CMG failure. 
NESC 2007 TECHNICAL UPDATE 13

TECHNICAL HIGHLIGHTS

SPACE OPERATIONS

Problem: Operational conditions for the 

solar arrays of the International Space Station (ISS) have been identified in which 

partial shadowing of the 108-foot long support masts can occur. This partial shadowing induces differential heating between the 

sunlit and the shadowed portions of the mast 

structure and the resulting thermal strains are 

predicted to buckle the mast in as little as 30 

minutes. The condition was not considered 

in the original design of the mast. The 30 

minute maximum exposure time has added 

complexity to controlling the solar arrays to 

avoid failure and raised concerns for mast 

buckling if attitude control were lost for any 

considerable period of time. The ISS Program management requested that the NESC 

conduct an independent assessment of the 

thermal and structural analyses predicting 

the failure and time to effect.

NESC Contribution: The NESC conducted an 

initial assessment of the analyses and did not 

find any modeling or analysis assumptions or 

techniques that could be improved to gain 

more margin and lengthen the time to mast 

buckling. However, it was observed that this 

partial shadowing thermal condition was not 

tested in the mast’s original development or 

qualification process. Thus, the NESC is preparing a ground test program to provide the 

best possible thermal and structural response 

data for correlation of the mast models. All 

other previous mast structural test data has 

also been reviewed for incorporation in the 

model correlation. The NESC has contracted with the mast manufacturer to design and 

fabricate a special mast test section that will 

be instrumented and exposed to a simulated 

space vacuum and solar environment in the 

Jet Propulsion Laboratory’s 25-foot diameter Space Simulator facility. Buckling of 

the test article due to thermal strain will be 

demonstrated and the temperature, strain, 

and displacement responses of the test article will be recorded for use in subsequent 

model updating.

Results: The NESC will provide test-correlated thermal and structural models of the 

solar array masts, and updated predictions 

of the mast buckling failure load under the 

partial shadowing condition. In consultation with the ISS Structures and Mechanisms 

team, the NESC will recommend the appropriate mechanical loads to be considered 

simultaneously with the buckling loads and 

a time to effect buckle limit to be used as an 

operational constraint.

International Space Station Solar Array Mast Shadowing

Problem: Reinforced carbon-carbon (RCC) 

is used on the Space Shuttle orbiter wing 

leading edge (WLE) and nose cap to protect it from temperatures during entry that 

exceed 2300° F. Recently, the outer silicon 

carbide (SiC) protective coating of the RCC 

has shown reduced adherence to the underlying carbon substrate. Three instances have 

occurred where small fragments of SiC liberated from the RCC, and one case where a 30 

inch-long subsurface region of reduced adhesion was discovered.

NESC Contribution: The NESC is working 

with the Leading Edge Structural Subsystem 

(LESS) Problem Resolution Team (PRT) to 

discover the root cause of the anomalies and 

to develop improved nondestructive evaluation (NDE) methods for inspecting the RCC. 

NASA Technical Fellows and members of 

the NESC’s Materials, Structures and NDE 

technical discipline teams (TDT) have been 

involved with this effort. The NDE TDT 

has developed a new method of quantifying 

data from infrared imaging of the RCC panels to evaluate and compare indications that 

may represent loss of SiC adhesion.

Results: The NESC has and will continue to 

assist the LESS PRT with RCC testing and 

analysis in pursuit of a resolution of this issue and to maximize safety of flight.

Orbiter WLE RCC Panel Subsurface Anomaly

Example of

solar array self 

shadowing event. 

The upper solar 

array blanket is 

placing one of 

the mast’s four 

longerons in 

shadow, causing 

it to contract and 

potentially buckle 

the mast.

Damage to RCC panel

8R, post STS-114, found 

to have weakened SiC

to carbon substrate

adherence after excavation 

of a 30-inch long region.

The NESC developed an 

improved imaging

capability to better

quantify this type

of damage.

NASA

KSC

Shadowed 

Longeron

NASA
14 NESC 2007 TECHNICAL UPDATE

TECHNICAL HIGHLIGHTS

SPACE OPERATIONS

Problem: As a result of a severe thunderstorm which produced hailstones measuring up to 0.8 inches in diameter, the External Tank (ET) used on STS- 7 incurred 

extensive hail damage to its thermal protection system (TPS) foam insulation.

NESC Contribution: The NESC was asked 

to assess the feasibility of repairing the ET 

TPS and of conducting those repairs with 

the vehicle in a vertical configuration in the 

Kennedy Space Center Vehicle Assembly 

Building (VAB). The NESC participated 

in technical discussions surrounding the 

inspections, repair categorization, and the 

repair process and reviewed supporting 

planning, testing and analysis. A human 

factors assessment was performed of the 

VAB work environment and the adequacy 

of the process controls applied to standard 

and non-standard repairs of the TPS foam. 

Concern about the debris potential posed 

by undetected crushed foam remaining on 

the ET and the adequacy of various repair 

techniques were also addressed. The NESC 

evaluated flight rationale for the non-standard repair processes and the flight risk associated with prelaunch icing and thermal 

conditions during ascent. 

Results: The NESC found that tests and 

analyses performed to substantiate repairs 

planned for the ET were well-formulated and 

provided an adequate foundation for flight 

rationale. However, some process catches 

( a problem found during normal processing) and escapes (a problem found after it 

should have been identified during normal 

processing) were observed. Trend analysis 

was recommended on both process catches 

and process escapes to maximize the potential for identifying and correcting process 

control issues in the future. Improvement 

of the repair processes could also be gained 

via a detailed Process Failure Modes and Effects Analysis and process sensitivity study. 

The repairs to the tank were completed and 

STS-117 was successfully launched.

External Tank Hail Damage 

Repair Assessment

United Space Alliance personnel, Nancy Lewis and Jessie Lawhorn, repair damage to the External Tank’s 

foam insulation caused by hail damage while Atlantis was on the launch pad at KSC.

Problem: The Space Shuttle is equipped with 

fuel cells that generate direct current electricity. The direct current is then converted into 

3-phase alternating current and distributed 

throughout the spacecraft. Each fuel cell uses 

the 3-phase current to power two internal 

motors – a coolant pump and a hydrogen 

separation motor. Prior to launch, STS-115 

experienced a momentary short on one of 

three phases in a fuel cell’s electrical output 

power. The short was attributed to a failure 

of the coolant motor within the fuel cell. 

During the mission, the fuel cell’s motors 

were operated on two phases and the launch 

proceeded without further fuel cell issues. 

NESC Contribution: The NESC was asked to 

determine if the fuel cell’s hydrogen separator 

motor was damaged by the two-phase operation. Consultation was also requested on what 

failure analysis was needed to understand the 

cause of the fuel cell motor anomaly and to 

make recommendations regarding the value 

of failure analysis on other motors inside the 

affected fuel cell. The NESC performed the 

requested damage assessment and participated on a project team for the anomalous 

motor failure analysis. 

Results: The analysis indicated that the hydrogen separator motor was not significantly 

stressed by the two-phase operation. Testing 

showed that the failed coolant pump contained defects consistent with manufacturing 

irregularities, and thermal and mechanical 

stresses that have accumulated over the motor’s 30 year life. 

KSC

KSC

Space Shuttle fuel cell

Fuel Cell Motor 

Two-Phase

Operational 

Evaluation

UTC Fuel Cells
NESC 2007 TECHNICAL UPDATE 15

TECHNICAL HIGHLIGHTS

SPACE OPERATIONS

Chipped Gear Anomaly in Space

Shuttle Rudder/Speed Brake

Problem: During performance verification, 

damage was found on the planet gear teeth 

of a Space Shuttle Rudder/Speed Brake 

(RSB) actuator containing new build hardware. As a result, a concern existed that liberated debris could cause jamming or binding and degrade the performance of RSBs or 

Body Flap Actuators (BFA) containing the 

new build hardware. This issue presented a 

potential launch constraint for the STS-117 

and STS-118 missions. 

NESC Contribution: The NESC was requested to participate on a Tiger Team to support 

the damage assessment. Members of the 

Mechanical Systems Technical Discipline 

Team worked closely with the Mechanical 

Flight Controls Problem Resolution Team 

in developing tests designed to address the 

ability of the RSB and BFA hardware to tolerate debris. Testing included placing gear 

chips, obtained from actual planet gears, 

into specified gear and bearing locations 

in a RSB actuator to encourage jamming 

and binding. In no instance was jamming 

observed and in all cases, the torque spikes 

produced were within the torque capability 

of the actuator to drive through the debris. 

In addition, a RSB unit with the original 

chipped planet gear present was subjected 

to a full rotation ultimate load test with no 

jamming or binding resulting and no additional gear chipping observed. A successful 

system level test and subsequent Acceptance 

Test Review was performed for a total of 64 

mission duty cycles on a RSB actuator with 

five chips present in the actuator. Members 

of the NESC team performed spur gear 

testing that demonstrated a linear relationship between the chip size and torque spike 

observed. Members of the NESC Engineering Statistics Team provided reliability and 

Weibull analyses, supporting the Tiger 

Team’s finding. Based on the maximum 

power drive unit torque output available, 

acceptable torque margins were present in 

all gear and bearing locations tested.

Results: Flight rationale for upcoming 

missions based on testing and inspections 

was presented to the Orbiter Project Office. The root cause of the chipping was 

attributed to improper handling during a 

critical heat treatment phase of the manufacturing process when steel is most susceptible to handling damage. The failure 

itself was attributed to internal stress rupture resulting from a subsurface crack produced by the high residual stresses present 

in the material. 

Problem: In June , 2007, all five active computers in the Russian Segment went off-line 

and operation remained erratic. The Russian 

computers provide attitude control for the International Space Station (ISS) by operating 

reaction control thrusters. The US Control 

Moment Gyros provide only fine control and 

saturate at large rates. During the erratic computer behavior, the docked Space Shuttle was 

used to stabilize the mated ISS/Space Shuttle 

Configuration.

NESC Contribution: The NESC was asked to 

contribute expertise to assist in the resolution 

of the ISS computer shut-down and attitude 

control anomaly. As a result, on-site support 

was provided to the anomaly resolution process at JSC during the mission. The Russian 

computer system was analyzed and critical 

simulations and analyses needed to ensure a 

safe undock and separation of the orbiter from 

ISS were identified and executed.

Results: Contamination or corrosion observed 

on a Russian BOK3 relay box connector and 

harness that contained on/off commands for 

the computers was identified as the cause for 

the computer shut-down anomaly. In addition, follow-on actions were completed to 

implement contingency attitude control plans 

for ensuring long term stability of the ISS in 

the event the Russian computer-controlled 

thruster-based system capability is lost.

Russian ISS

Computer

Evaluation

The NESC contributed realtime assistance to the ISS 

computer anomaly investigation team.

NASA

GRC

(Left) Cutaway 

illustration of the 

Space Shuttle Orbiter 

Rudder/Speed Brake 

actuator. The NESC 

investigated concerns 

that chips from a gear 

tooth (above) could jam 

the actuator.
TECHNICAL HIGHLIGHTS

EXPLORATION

16 NESC 2007 TECHNICAL UPDATE

Apollo 17 Mission Commander Eugene (Gene) Cernan next 

to the Lunar Roving Vehicle during Extra Vehicular Activity -3. Lunar dust interfered with the smooth operation of

numerous mechanisms on the suits and infiltrated the 

Lunar Module cabin causing breathing irritation for fellow 

astronaut Harrison Schmitt.

TECHNICAL HIGHLIGHTS

EXPLORATION
TECHNICAL HIGHLIGHTS

EXPLORATION

NESC 2007 TECHNICAL UPDATE 17

Lunar Dust Workshop for Exploration 

Problem: Lunar dust may pose engineering, 

scientific, and medical issues relating to the 

exploration of the Moon, both crewed and 

robotic. While many different points of view 

on the issues and how to address them have 

been voiced, a clear consensus on a forward 

plan was needed.

NESC Contribution: The NESC sponsored a 

Lunar Dust Workshop in late January, 2007, 

at the Ames Research Center. The workshop 

brought together a diverse group of individuals from NASA Centers, academia, and industry. Participants included researchers who 

are currently studying lunar dust, as well as 

the designers and operators of the hardware 

that will function on the Moon.

Results: Discussions centered on four areas: 

basic research, mechanical systems, medical 

and health, and support systems. Workshop 

participants agreed that the characteristics 

(physical, chemical, mechanical) of lunar 

dust and the lunar plasma environment need 

to be better understood. This process can be 

started by mining existing data from Apollo, 

Lunar and Prospector missions and continued with in-situ measurements from robotic 

missions. A robust qualification test program 

based on approved understanding, sensitivities and mitigation should be developed and 

implemented. In order to carry out rigorous 

tests of the effects of dust on mechanical systems and on humans, realistic simulants of 

lunar dust must be developed and tested as 

returned samples of useful lunar dust are in 

short supply. Medical studies require a systematic framework beginning with in vitro 

and in vivo studies to understand the biological effects of dust, to determine the effects of 

acute versus chronic exposure to dust, and to 

find ways to predict individual responses to 

dust. Mitigation technologies must be designed, developed, tested, evaluated and selected to limit the exposure of astronauts to 

the dust and to prevent or limit the damage 

caused to mechanical systems by dust. Issues and potential solutions related to lunar 

dust are being compiled into an integrated 

Agency perspective on lunar dust. This will 

allow identification of proactive testing and 

analysis that should be conducted in the 

near term. 

Apollo 17 Mission 

Commander 

Eugene Cernan

in the Lunar

Module after

the third moon 

walk. Lunar dust 

is evident on his 

pressure suit.

“I think dust is probably one of our 

greatest inhibitors to a nominal 

operation on the Moon. I think 

we can overcome other physiological or physical or mechanical problems except dust.” 

Gene Cernan 

Apollo 17 Technical Debrief

The NESC held a workshop on Lunar Dust to focus efforts for the benefit of the Constellation Program.

NASA

NESC

NASA
TECHNICAL HIGHLIGHTS

EXPLORATION

18 NESC 2007 TECHNICAL UPDATE

NESC Composite Crew Module Design Project

Problem: In 2006, the NESC studied the feasibility of a composite pressure vessel for the 

Orion Crew Module (CM). The overall finding indicated that a composite crew module 

was feasible but that a detailed design would 

be necessary to quantify technical characteristics, particularly in the area of mass and 

manufacturability. Accordingly, the NASA 

Administrator, Associate Administrator for 

Exploration Systems, and the Constellation 

Program Manager chartered the NESC to design, build, and test a composite crew module with the goal of developing a network of 

engineers within the Agency who would have 

hands-on experience using composites on 

habitable spacecraft design.

NESC Contribution: The NESC Composite 

Crew Module (CCM) Project objective is to 

design, build, and test a structural test article 

of the CEV Crew Module primary structure. 

The project was chartered in January 2007, 

with the goal of delivering a test article for 

structural testing 18 months after project 

initiation. The project team is a partnership 

between NASA and industry and includes 

design, manufacturing, and tooling expertise. Partners include civil servants from 

ARC, GRC, GSFC, JSC, JPL, KSC, LaRC, 

MSFC, Air Force Research Laboratories and 

contractors from Northrop Grumman, Lockheed Martin, Genesis Engineering, Alliant 

Techsystems, Janicki Industries, and Collier 

Corporation.

Results: The CCM team constrained the 

design to match interfaces with the current 

Orion CM including the internal packaging 

constraints that utilize a backbone for securing internal components. During the first 

two months of the effort the team evaluated 

design solutions and focused in on a design 

that utilizes predominantly aluminum honeycomb sandwich and solid laminate material systems. One unique feature of the CCM 

design was the integration of the packaging 

backbone structurally with the floor and 

walls of the pressure shell. This provides a 

load path that accommodates load sharing 

with the heatshield for water landing load 

cases. An independent panel reviewed the 

initial concept and preliminary design. The 

project is currently conducting building block 

testing of critical areas and the results of the 

building block testing will be used to validate 

critical assumptions for the final design that 

will be independently reviewed again at the 

Critical Design Review (CDR) near the end 

of calendar year 2007.

n Solid Laminate Tunnel

n Sandwich Upper Pressure Vessel

and Gussets (X6)

n Manufacturing Splice Joint

n Sandwich Barrel Lower Pressure Vessel

n Metallic/Composite SM/ALAS

 Attachments

n Multi-lobed Sandwich Dome

CCM Pressure Vessel Design Result

(From left) Craig 

Newland of Northrop 

Grumman, Larry 

Pelham, NASA Manufacturing Lead, Nathan 

Oldfield of Northrop 

Grumman, and Terry 

Graham of ATK, lay-up 

the first ply of carbon 

epoxy fabric that will 

later become one of 

the sub-element test 

articles as part of the 

building block

approach being used 

for the NESC Composite Crew Module 

Project.

Graphic: NESC

MSFC
TECHNICAL HIGHLIGHTS

EXPLORATION

NESC 2007 TECHNICAL UPDATE 19

Problem: The Orion Project requested a risk 

comparison of the Integrated Landing and 

Recovery System (LRS) designs developed 

by NASA and the Contractor for the Orion 

Crew Module. Based on the results of this risk 

comparison, the NESC was further asked to 

evaluate risks identified by the Orion Project 

to risk reduction and mitigation strategies. 

NESC Contributions: The NESC formed a 

comprehensive assessment team that included Apollo engineers and astronauts. The team 

first analyzed the LRS baselines and qualitatively evaluated the risk to the flight crew in 

each baseline. Configurations included water 

landing and land landing configurations Several areas of risk and mitigations that could 

improve crew safety in off-nominal situations 

were investigated.

Extensive analysis was performed using an 

NESC-developed tool to understand the 

number of landing opportunities over a period of time given a site’s accessibility and 

availability. Accessibility was based on the 

site location, vehicle capabilities to reach 

the landing sites from International Space 

Station orbital trajectories, and operational 

procedures. Availability was based on the 

predicted winds at the landing site, vehicle 

horizontal wind limit, and day/night landing 

restrictions. This tool could prove useful in 

developing the Orion flight test program.

Alternative crew protection and crashworthiness concepts were investigated using finite 

element models of Hybrid III crash test dummies used in the auto industry. The models 

were modified by the NESC and evaluated/

calibrated against the NASA standard human 

impact tolerance model used by the Orion 

Project. The NESC models were used to 

quickly evaluate the relative performance of 

crew protection concepts for areas of the human body where the NASA model could not 

provide sufficient injury prediction.

Results: The integrated risk analysis predicted the lowest risk for water landings while 

the landing site accessibility and availability 

analysis showed that land landing opportunities could be restricted to a few times per 

week in certain circumstances for preferred 

sites. The crew protection and crashworthiness concepts led to additional requests from 

the Orion Project for further, independent 

investigations of human impact tolerance 

modeling and crew protection mechanisms. 

Problem: Traditionally, acceleration measurements are used to reconstruct flight loads in 

structures. The penalties of using only acceleration are the weak correlation of Coupled 

Loads Analysis (CLA) and conservative qualification testing. Thus, a need exists to utilize force measurements in the CLA process. 

Force measurements will greatly benefit all 

future missions and could dramatically impact the Orion Crew Module requirements 

and development. 

NESC Contribution: The Flight Forces Discipline Team is demonstrating the benefits of acquiring interface force measurements during 

flight. Ideally, this would be accomplished via 

force transducers. However, force transducers are in the load path and require significant 

integration effort and lead-time that is not 

available. A simplified approach will be used 

that involves mounting of strain gages near a 

spacecraft interface such that forces and moments may be derived. The NESC is developing methodologies to predict interface forces 

based on these strain measurements that will 

be validated in ground testing. Methods will 

be demonstrated through analysis and testing 

of the trussed Payload Adapter Fitting (PAF) 

to be flown on the Gamma-Ray Large Area 

Space Telescope (GLAST) mission. The PAF 

design used on this flight is the most suitable 

test article for resolving forces based on strain 

measurements.

Results: GLAST is scheduled to be launched 

on a Delta II in 2008. Post-flight data analysis will be performed to reconstruct the flight 

loads and reconcile the predicted forces, document the benefits of force measurements 

and to make recommendations for further 

Agency action.

Flight Force Measurements to Improve Coupled Loads

Testing of a concept: strain gages can be used to extract forces and moments from a complex payload 

adapter structure (inset) like the GLAST Test Payload 

Attach fitting.

CEV Integrated Landing and Recovery System Assessment

GRC

Finite element models of 

the Hybrid III crash test 

dummy were adapted to 

evaluate crashworthiness 

concepts for the Orion 

crew seats.

NESC

KSC

GSFC
TECHNICAL HIGHLIGHTS

EXPLORATION

20 NESC 2007 TECHNICAL UPDATE

Assessing GN&C 

System Architecture 

Commonality for 

Constellation

Problem: The induced acceleration and 

vibration environments that will be experienced during Orion-Ares launch, abort, 

reentry, and landing phases of flight pose 

specific and significant challenges for 

maintaining the health and performance 

of the astronaut crew. Gaps in our knowledge concerning acceleration and vibration loading may impact NASA’s ability to 

design safe and effective space systems for 

operation during these phases of flight.

NESC Contribution: The NESC conducted 

the AGILE (Assessment of Gravito-inertial Loads and Environments) Project 

workshop, which was held in October 

2007. The workshop brought together 

over 60 NASA and contractor members 

for the Orion and Ares projects, external 

(military, academia and industry) subject 

matter experts, and present and former 

astronauts for plenary talks and breakout 

working sessions. During these sessions, 

crew health and performance concerns and 

Constellation Program system development for these induced environments were 

discussed.

Results: Two significant Constellation 

Program gaps were identified at the workshop: 1) incomplete and, as yet undeveloped, models and test data for induced 

acceleration and vibration environments 

and system structural response, and 2) 

incomplete knowledge of expected crewsystem interactions during these induced 

environment phases of flight. Orion and 

Ares attendees acknowledged the meeting 

heightened their awareness of the interrelation between these induced environments 

and crew health and performance, and of 

the absence of pertinent data and models.

A review of the open literature and of 

non-public archives on the impact of acceleration and vibration loading on human 

health and performance is continuing. The 

final AGILE product will be a comprehensive report that captures the workshop output and ongoing literature review, identifies and prioritizes critical knowledge gaps, 

and proposes a path to close those gaps 

that represent significant risks to the Constellation Program cost/schedule and mission success.

Human Factors Workshop

Former astronauts Dr. Joe Kerwin (left) and Capt. John Young (right) discussing gravity and vibration loading during simulation, training, and flight with AGILE Workshop attendees.

ARC

Problem: Guidance, Navigation and Control 

(GN&C) systems for the Exploration Systems 

Mission Directorate (ESMD) and the Constellation Program stand out, among all the 

future spacecraft systems, as an area wherein 

commonality might be of technical and programmatic benefit. Commonality between 

exploration system hardware and software 

elements may offer the potential to increase 

sustainability by reducing both non-recurring 

and recurring cost/risk. 

NESC Contribution: The NESC team is working to assess the potential for GN&C system 

commonality across the emerging new generation of space vehicles that will be designed 

and built for the exploration of the Moon and 

Mars. The team is performing an independent, 

systematic and comprehensive study on the 

problem of optimizing GN&C architectures 

across exploration space vehicles in terms of 

crew safety, reliability, robustness, minimum 

complexity, commonality, testability, ease of 

operation, sustainability, extensibility and 

affordability. The task leverages analytical 

methods developed at the Massachusetts Institute of Technology as part of their program 

in Technical System Architecture, as well as 

their specialized analysis tools/methods used 

to support the ESMD Concept Exploration 

and Refinement study. Preliminary results 

will be available in 2008.

A concept image shows the Ares V cargo launch vehicle. 

The heavy-lifting Ares V will become NASA’s primary 

vessel for safe, reliable delivery of large-scale hardware 

to space. 

NASA
TECHNICAL HIGHLIGHTS

EXPLORATION

NESC 2007 TECHNICAL UPDATE 21

Alternative Launch Abort System (ALAS)

Solution for Orion Crew Module

Problem: The Orion Project identified a significant technical and 

programmatic risk related to large 

aeroacoustic loads predicted during nominal Orion/Ares 1 launches 

and aborts. This risk identification 

coincided with the presentation of 

the NESC ALAS feasibility study 

team’s initial results in December 2006, that showed significant 

aerodynamic performance benefits for ALAS configurations. The 

Orion Project requested the ALAS 

Team refocus their efforts on evaluating the aeroacoustic benefits 

of the ALAS design concept, and 

to perform higher fidelity aerodynamic and ascent performance assessments, and high-fidelity abort 

stability and control evaluations.

NESC Contribution: The NESC expanded the ALAS Team to include 

participation from multiple NASA 

Centers. The team created a family 

of ALAS configurations for study 

and evaluated the ALAS benefits 

through higher fidelity computational fluid dynamics (CFD) simulations, a 

wind tunnel test focusing on launch stack 

aerodynamics, two wind tunnel tests to evaluate launch abort vehicle stability and control forces/moments, an acoustic wind tunnel 

test to determine local fluctuating pressure/

aeroacoustic loads, and dynamic stability and 

control simulations for pad and maximum 

dynamic pressure abort cases. Study results 

were presented to the Orion Project and the 

Orion contractor staff. The ALAS Team was 

asked to continue their efforts through support of a Project-led study of ALAS 

Results: The Orion Project assessment largely confirmed the NESC ALAS Team’s results, 

and the significant acoustic loads reduction 

obtained for the ALAS configurations led to 

adoption of ALAS as an integral element of 

the “point of departure” configuration for the 

Orion Preliminary Design Review (PDR).

Two significant findings from this study benefited the Orion Project: 

1) The improved launch abort vehicle (LAV) 

aerodynamics of ALAS configurations allowed for safer pad abort performance since 

downrange and altitude constraints could be 

readily met by the ALAS LAV due to its higher lift and lower drag characteristics. 

2) The original understanding of the Orion 

Crew Module (CM) aeroacoustic noise 

sources was that they were due to the wakes 

from exposed LAV nozzles and the large 

flow separation regions on the Orion Service 

Module. Wind tunnel testing with various 

nozzle shroud configurations, with nozzles 

removed, and with various outer mold line 

geometries, proved that the nozzle wake had 

only a secondary effect on the acoustic loads. 

A strong oscillating shock due to the Orion 

CM bluntness was discovered to be a previously ignored source, and the ALAS configurations that weakened this shock were the best 

aeroacoustic performers. Therefore, study of 

shock structures using static CFD computations were found to be excellent design aids 

in defining low noise vehicle configurations 

and reduced the amount of iterative testing 

of vehicle configurations.

NESC

Dr. Charles Camarda, 

NESC Deputy Director for 

Advanced Projects (left),

and Dr. Stephen Scotti,

ALAS Study Lead, display

an ALAS wind tunnel model.

The NESC led a multi-Center 

effort to develop a fairing 

concept for the Orion CM 

that reduces aerodynamic 

drag and aeroacoustic

pressure levels.

The ALAS shape

(right) is now

being used by

the Orion

Project.

NESC
TECHNICAL HIGHLIGHTS

EXPLORATION

22 NESC 2007 TECHNICAL UPDATE

Problem: High-performance aerospace shell 

structures are inherently thin-walled because 

of weight and performance considerations. 

Reliable, validated design criteria for thinwalled shells are required, with buckling 

being an important and often critical consideration in the design of these structures. 

Currently, aerospace shell structures are designed using buckling criteria established in 

the 1960s based on experiments with metallic 

shells. Buckling design allowables were used 

with the shell analyses to “knockdown” the 

analytical predictions that were observed 

to over predict failure loads. This approach to shell design remains prominent 

in industry practice, as evidenced by the 

extensive use of the NASA space vehicle 

design recommendations. In more recent times, significant improvements 

in nonlinear structural analysis codes 

and advanced experimental-response 

measurement systems have uncovered new insights into the complex 

behavior of thin-walled shells. The 

tools and understanding now exist 

for developing high-fidelity, analysis-based shell-buckling knockdown 

factors for shells of general shape 

and material composition and for 

combined mechanical and thermal 

loads. Thus, high-fidelity analyses 

and selective structural testing can 

be used to determine refined, reliable 

design criteria for shell buckling that 

are not overly conservative like the 

approaches currently being used.

NESC Contribution: The NESC is 

developing new analysis-based shell 

buckling knockdown factors for 

the Ares-I Upper Stage LH2 tank 

structure that would reduce design 

conservatism and enable significant 

weight savings. The NESC has assembled a team of discipline experts 

from MSFC and LaRC to define a 

program that involves specimen fabrication and testing for knockdown 

factor validation. Initial results will 

be available in 2008.

Shell Buckling 

Knockdown 

Factor Proposal

Problem: The Ares I-X is a development 

flight test vehicle which will gather 

performance data of the first stage for 

Ares I. Ares I-X includes an inert Upper 

Stage Simulator that is composed of segments bolted together through welded 

flanges. The flangeto-skin welds are 

in the primary load 

path, which makes 

any cracks or defects 

in the weld region 

critical. The Ares I-X 

Project requested an 

independent assessment and prediction of the minimum 

weld defect shape and size which could 

grow into a critical crack. This information was required to determine the weld 

inspection threshold and to establish 

weld repair criteria.

NESC Contribution: The NESC Team 

worked jointly with the Ares I-X Project and established a set of loads for the 

structural analysis. Using these loads, 

the NESC Team assessed the Ares IX Upper Stage Simulator stresses and 

critical initial flaw sizes for the flangeto-skin welds using state-of-the-art 

analytical tools that are readily available 

within NASA. The team is also performing crucial tests to develop appropriate 

material property values for the specific 

weld joint configurations and different 

weld types. 

Results: The NESC Team will provide 

test results to the Ares I-X Project for 

use in further analysis. The NESC team 

will also make recommendations regarding critical initial flaw size that can 

be tolerated by the structure and specific crack sizes and shapes that should 

be considered unacceptable.

Lesson Learned: When using new materials, materials property characterization tests need to be performed as soon 

as possible.

NESC TECHNICAL UPDATE 2007

Critical Flaw Size Analysis for 

Ares I-X Upper Stage Simulator

GRC

GRC workers monitor a critical lift of an Ares I-X Upper Stage simulator section. Each section of the 

inert mass simulator is being manufactured at GRC.

The Ares I-X

Upper Stage

fuel tank

shown covered

in orange

insulation

foam.
TECHNICAL HIGHLIGHTS

EXPLORATION

NESC 2007 TECHNICAL UPDATE 23

Lunar Surface Access Module (LSAM) Design Support

Problem: The Constellation Program requires 

a lunar lander vehicle capable of supporting 

crewed and cargo missions to the lunar surface. As a result, the Program established a 

Lunar Lander Project team that has begun 

conceptual design studies of lunar lander 

configurations. The challenge is to develop 

unique and innovative design concepts that 

are mass and packaging efficient and, at the 

same time, satisfy lunar mission architecture requirements. An LSAM Structures and 

Mechanisms Design Team was set up by the 

Project Lunar Lander to conduct studies of 

an LSAM capable of supporting crewed and 

cargo missions to the lunar surface. 

NESC Contribution: The lander design team 

consists of a strong contingent of experts derived from the NESC Composite Crew Module (CCM) Team, along with other engineers 

from across NASA. Experience and lessons 

learned (both technical and procedural) from 

the NESC CCM team have been useful in facilitating and developing a model for LSAM 

design work. The team is conducting its 

work through regular co-locations and webbased virtual design sessions. 

Results: Preliminary results for “Lander 

Design and Analysis Cycle One” (LDAC-1) 

included detailed design concepts, finiteelement models, and initial mass estimates. 

The work also included the development 

of detailed loads models, mechanisms, and 

landing-gear design options. The team is now 

working on modifications to the first-look 

lander design that optimized the configuration for cargo-only missions. The NESC will 

continue supporting the LSAM Structures 

and Mechanisms design team to ensure that 

the Agency-wide expertise assembled for 

CCM will be leveraged to the maximum extent possible by the LSAM team.

Max Launch Abort System (MLAS) Development

Problem: The NASA Administrator and the 

former Associate Administrator of the Exploration Systems Mission Directorate tasked 

the NESC to design, develop and test an alternate concept Launch Abort System (LAS) 

for the Orion Crew Module (CM) as a risk 

mitigation for the Orion Project’s LAS development. Having an effective means for 

the crew to escape in an emergency during 

launch is critical in establishing launch system reliability and crew safety for the AresI launch vehicle. An alternate LAS design 

could reduce overall schedule risk by providing the Constellation Program management 

with a fallback design concept. Due to LAS 

complexity, a flight demonstration is necessary to validate design and performance assumptions in a safety-critical system such as 

the LAS. An alternative LAS must also meet 

all performance requirements of extracting 

the Orion CM from the launch vehicle at 

any time from crew ingress at the launch pad 

through staging and successful ignition of the 

second stage of the Ares-I.

NESC Contribution: Using an intra-agency 

technical team and working with industry partners, the NESC is developing a 

launch abort concept that can be used 

for all launch abort conditions and for a 

nominal launch consistent with Constellation Program requirements. The concept is known as the Max Launch Abort 

System (MLAS), and will be designed 

to lift the Orion CM from the launch 

pad to an altitude high enough and with 

enough distance downrange to permit the 

CM to execute a nominal landing. MLAS 

performance will be evaluated through an 

actual Pad Abort test. 

Results: The NESC is currently in the design analysis cycle process and procuring the 

hardware necessary to demonstrate a fullscale Pad Abort test of MLAS in Fall, 2008, 

at the Wallops Flight Facility. 

Illustration of an early concept investigated for the 

LSAM. The design will evolve over multiple design 

analysis cycles.

NASA

Interior view

External view

Graphic: NESC

Internal and external views of the 

MLAS concept. The fairing shape 

provides increased aerodynamic

performance and reduced

aeroacoustic notice levels

over the baseline LAS.
TECHNICAL HIGHLIGHTS

EXPLORATION

24 NESC 2007 TECHNICAL UPDATE

LOCKHEED MARTIN

Design, Development, Test and Evaluation (DDT&E) 

for Safe and Reliable Human Rated Spacecraft Systems

Problem: NASA is designing the next generation of human-rated vehicles that will take 

astronaut crews to the Moon and beyond 

in the next two decades. To support this 

endeavor, the Johnson Space Center (JSC) 

Astronaut Office asked the NESC to take a 

fresh look at the fundamental principles for 

developing safe and reliable human-rated 

spacecraft systems that should be considered 

during the formative phase of the Constellation Program.

NESC Contribution: A multi-disciplinary 

NESC team collected methodologies for developing safe and reliable human-rated space 

systems and identifying the drivers that provide the basis for assessing safety and reliability. Using a wide variety of resources including historical systems, subject matter experts, 

and contemporary engineering practice, the 

team identified techniques, methodologies, 

and best practices to assure that NASA can 

develop safe and reliable human-rated systems. 

Results: The NESC published a two volume 

report on Design, Development, Test, and 

Evaluation (DDT&E) Considerations for 

Safe and Reliable Human Rated Spacecraft 

Systems. Volume I contains the overall systems engineering process along with three 

top level conclusions and seven guiding principles. Volume II contains expanded detail in 

nine discipline-specific sections.

Lessons Learned: The lessons learned by the 

NESC team are captured in the three top level conclusions. First, history indicates that no 

subsystem, component, or system element is 

immune from failure. It should be assumed 

that failures will occur and they should be 

planned for. Second, there is no single requirement, method, or process, which by 

itself assures the “right stuff” for safety and 

reliability. Cookbook approaches should be 

avoided and multilayered defenses should be 

used. Third, system level safety and reliability 

are achieved by maintaining a focus on these 

attributes throughout the DDT&E life cycle 

and during spacecraft operations. Potential 

problems should be anticipated by keeping a 

mindful preoccupation with failure, a reluctance to simplify interpretations, and a sensitivity to operations.
NESC 2007 TECHNICAL UPDATE 25

GENERAL

TECHNICAL HIGHLIGHTS TECHNICAL HIGHLIGHTS
26 NESC 2007 TECHNICAL UPDATE

TECHNICAL HIGHLIGHTS

GENERAL

Conax Y-PCA Pyrotechnical Valve Assessment

Problem: The Solar Dynamics Observatory 

(SDO) Project requested the NESC perform 

an independent assessment of a “non-firing” 

pyrotechnic valve issue which was experienced in two shock test failures of baselined 

Conax Y-PCA pyrovalves. Another occurrence of the anomaly was later reported in a 

Lockheed military program and reproduced 

by Conax engineering in troubleshooting of 

the Lockheed anomaly. All four of these failures were of similar configuration and operation. This device is broadly used by NASA, 

commercial, and DOD missions; near-term 

NASA missions include Solar Dynamics 

Laboratory (SDO), Phoenix and Mars Science Lab (MSL). 

NESC Contribution: The goals of the activity were to determine the root cause of the 

anomaly and to develop a clear understanding of how the device works with particular 

emphasis on ignition requirements at the 

booster interface. Test and analysis challenges were compounded by the small size of 

the device, the short timescales involved, and 

extreme environment during operation. The 

assessment included a series of “confidence” 

tests using live boosters, which attempted to 

duplicate the dual simultaneous fire anomaly, 

and single fire tests to demonstrate booster 

ignition margin. Other tests to understand 

the physics of device operation used novel 

techniques to measure temperature and pressure time histories, as well as combustion 

product distribution. 

The NESC team has provided guidance to 

programs already committed to using the device and has suggested improvements to the 

design.

Results: The NESC provided interim observations and findings to the SDO, Phoenix 

and MSL programs. That information included rationale for using the device in single 

fire operation, while highlighting likely contributors to the failure.

The SDO and Phoenix programs continue to 

baseline the use of the Conax Y-PCA for their 

upcoming missions, consistent with the operational recommendations and rationale the 

NESC provided. The MSL program, whose 

schedule allowed some investigation of PCA 

redesign, continued to develop and test an 

alternative design, which took into account 

many of the NESC observations and suggestions. Based on discussions with NESC, the 

new design is now baselined for MSL.

RTAX-S FPGA Risk Reduction

Problem: The NESC is conducting a risk reduction activity to reveal undocumented “design features” that pose a risk to flight programs that use the latest version of Radiation 

Tolerant Axcelerator - Space (RTAX-S) Field 

Programmable Gate Arrays (FPGA). The activity was initiated after numerous issues were 

discovered with the previous version of FPGAs. 

RTAX-S FPGAs are currently baselined for a 

number of Agency missions including Lunar 

Reconnaissance Orbiter, James Webb Space 

Telescope, Geostationary Operational Environmental Satellite, Mars Science Lab and the 

Orion Crew Module.

NESC Contribution: The NESC is working in collaboration with six NASA centers 

(GSFC, LaRC, GRC, MSFC, JSC and JPL), 

John Hopkins Applied Physics Lab and The 

Aerospace Corporation to develop a test 

plan for FPGAs and to peer review results of

testing.

Results: NESC support is an important element in the development of a critical body of 

knowledge on RTAX-S FPGAs that will enable informed decision making and improved 

reliability.

WSTF Technician 

Brooks Wolle 

prepares a Conax 

Y-PCA for an

X-ray scan.

An obstruction 

in one arm of the 

initiation path is 

evident (above).

Obstruction

WSTF

RTAX-S FPGA showing package cavity, 

die, and wire bonds.

NASA
NESC 2007 TECHNICAL UPDATE 27

GENERAL

TECHNICAL HIGHLIGHTS

Problem: Hybrid DC/DC converter flight 

failures have been observed or are suspected 

to have occurred on several NASA missions 

including GRACE, Hubble Space Telescope, 

and the International Space Station. In addition, numerous flight projects, both crewed 

and robotic, sustained severe pre-launch cost 

and schedule impacts due to hybrid DC/DC 

converter quality and application issues. Improved interpretation and use of converter 

specifications are needed. 

NESC Contribution: The NESC is conducting electrical testing of converters to develop 

recommended test methods for users. This 

will standardize the approaches and communicate among NASA Centers the most 

effective testing program. Leveraging upon 

many years of experience and the testing, the 

NESC will develop an Agency-level Guidelines Document to aid designers and engineers in the pitfalls when using these types 

of converters. The NESC will recommend 

changes for MIL-PRF-38534 hybrid specification to increase the acceptability of these 

parts.

Results: A DC/DC converter Usage Guidelines Document will be available in 2008. 

Test reports will be included in the Guidelines Document and available to projects for 

their use. A DC/DC converter usage and 

failure reference website will be created for 

NASA Projects. The NESC is also working 

with vendors to improve the data provided in 

specification sheets. 

Lessons Learned: A NASA website will track 

the usage of converters, as well as any failures. This data will be used to ensure that lessons-learned are communicated across NASA 

Centers, as well as being added to the Lessons 

Learned Information System (LLIS).

DC/DC Converter Investigation

Problem: Batteries are used in virtually every space mission, crewed or robotic. The 

differences in the mission application, mission duration, planned operations, and even 

NASA Center experience result in the use of 

a large array of batteries and, therefore, battery issues. Individual engineers communicate and consult with their known counterparts at other Centers; however, there is no 

coordinated NASA-wide approach to common issues. The large array of issues include: 

exceeding the recommended wet life prior 

to launch; recognizing cell degradation signatures, and understanding the features and 

limitations of new technology such as Li-Ion 

batteries. 

NESC Contribution: To address these issues, 

the NESC proactively initiated the Aerospace Flight Battery Program. This activity 

supports the validation and verification of 

aerospace battery systems for NASA missions with contribution from five different Centers, (MSFC, GRC, JPL, JSC and 

GSFC). The program is designed to enable 

the implementation and execution of critical 

test programs to reduce risk by addressing 

wide-ranging technology issues. The issues 

affect the safety and success of future NASA 

missions. The final products include Battery 

Procurement Guidelines, Guidelines for Wet 

Life of Ni-H2 Batteries, and Guidelines for 

Li-Ion handling, safety, qualification and 

material availability.

NASA Aerospace Flight Battery Working Group

GRC

GRC

Typical DC/DC converter with cover removed 

shows internal components (top) and radiographic image of components (bottom). The 

NESC is investigating ways to improve device 

reliability on deep space missions.

JPL

(Above) The Battery Working Group meets to work 

issues with existing batteries and to develop next 

generation batteries. (Right) GRC developed and validated designs for nickel hydrogen (Ni-H2) cells that 

have been adopted for NASA missions and employed 

by cell manufacturers and satellite companies.
28 NESC 2007 TECHNICAL UPDATE

TECHNICAL HIGHLIGHTS

GENERAL

A large Composite

Overwrapped Pressure

Vessel (COPV) is

heavily instrumented

for testing (left).

Numerous composite 

pressure vessels will

be used in the Orion 

Crew Module (below).

Problem: The use of and emphasis on light 

weight composite pressure vessels throughout 

the Agency by both human and robotic space 

programs is growing. As such, a NASA-wide 

multidisciplinary effort is required to understand the technology, to act as a technical 

resource to assist NASA Programs in solving 

current and future technical issues, and to 

stimulate advancements in the technology.

NESC Contribution: To address these issues, 

the NESC formed the Composite Pressure 

Vessel Working Group (CPVWG). An Agency-wide resource, the CPVWG is responsible 

for understanding composite pressure vessel 

design and analysis methods, standards and 

testing requirements and methods for existing, new and emerging technologies related 

to current and future needs of NASA Programs. Oversight of the CPVWG is provided 

by the NASA Technical Fellows disciplined 

in Materials, Structures, and Nondestructive 

Evaluation and membership includes technical experts from across NASA.

Results: The initial emphasis of the CPVWG 

is to support NASA’s human space flight related programs that involve composite overwrap pressure vessel (COPV) technical issues. The CPVWG is developing a materials 

data-base that will include all available data 

associated with carbon fiber stress rupture. 

Relevant data will be used by ISS and Constellation Programs for stress rupture life prediction analysis. The CPVWG is also developing 

an understanding related to the long term use 

of COPVs and the nuances associated with 

testing efforts required to fully characterize 

long term stress rupture. Results of this ongoing effort have led to direct input to the 

Orion Project team working on COPV stress 

rupture testing requirements. The working 

group is also developing state-of-the-art life 

prediction and mechanics models that will be 

required to understand and predict the long 

term use of COPVs. A physics-based understanding of existing stress rupture reliability 

models is being developed so that the true 

capabilities of COPVs is understood when 

considering COPV reliability predictions.

As no fracture mechanics-based methodology 

exists that can be reliably used to predict the 

fracture behavior of plastically deformed thin 

wall metal liners, proactive work is being conducted to develop a standard test methodology. The methodology could be used to obtain 

the low cycle crack growth data in the biaxial 

stress state field of a responding COPV metal 

liner. The CPVWG is also conducting a study 

to understand state-of-the-art associated with 

large composite tanks. Industry perspectives 

will also be captured. The output of this effort will be a comprehensive report that describes the current technology. The CPVWG 

is developing an Agency-wide expertise for 

standards by interacting with organizations 

that develop and maintain standards for use 

of pressure vessels.

Composite Pressure Vessel Working Group

WSTF
NESC 2007 TECHNICAL UPDATE 29

GENERAL

TECHNICAL HIGHLIGHTS

Problem: The NASA Chief Engineer requested an integrated technical summary of 

concerns associated with composite overwrap 

pressure vessels (COPVs) to assess if there are 

systemic issues with the COPV design, test, 

and operation. The activity was requested 

as the result of recent COPV issues including the inspection of a spare Space Shuttle 

Orbiter Main Propulsion System COPV and 

the detection of irregularities on the liner 

inner surface.

NESC Contribution: The NESC utilized the 

Composite Pressure Vessel Working Group 

(CPVWG) and other subject matter expertise to identify the principal observations associated COPVs. The NESC did not identify 

systemic issues with the design or application 

of COPVs that would suggest incipient failure of any pressurization system in service. 

The NESC team could not identify any common causes for the noted design, analysis, 

fabrication, inspection, test, or operational 

issues.

Results: The NESC delivered a technical 

report that summarized critical aspects involved with the industry standard for COPV 

design, analysis, and test; COPV failure 

modes and damage mechanisms; relevant 

COPV anomalies; and a summary of current 

COPV and related investigations.

Composite Overwrap Pressure Vessel Technical Issues

Problem: The NESC is currently leading the 

Agency’s efforts to perform independent data 

mining and trend analysis to identify unknown indicators of future problems. One 

of the NESC goals is to strengthen the Agency’s capabilities to perform data mining and 

trending, both within and across programs 

and projects.

NESC Contribution: The NESC is leading the 

Agency’s Data Mining and Trending Working Group. The working group is comprised 

of experts from across the Agency, as well as 

from industry, academia and other government agencies, such as the Federal Aviation 

Administration, Department of Homeland 

Security, National Transportation Safety 

Board and the Institute of Nuclear Power 

Operations. This year the working group 

established a Data Mining Response Team 

to provide expert data mining analytical capabilities to programs, projects and institutions The goal is to both address the specific 

data mining problems and needs, while also 

providing an opportunity for the requesting 

organization to learn how to apply a tailored 

approach to data mining in their domain. 

Results: The NESC’s collaboration with 

other organizations has enabled the exchange 

of ideas, particularly regarding methodology 

and lessons learned. The group is assisting 

NASA organizations in strengthening trending activities for the Agency’s programs and 

projects. This is being accomplished in part 

by developing a data mining toolbox. In 

addition, the response team has undertaken 

tasks for the Crew Exploration Vehicle (CEV) 

Test and Verification Team to explore and analyze International Space Station data needed 

to support the system-level environmental 

acceptance testing approach and development process for CEV.

Data Mining and Trending Response Team

Professor Kevin Knuth presents his work on sampling and heuristics at the 2007 data mining conference.

WSTF Project Manager Regor Saulsberry briefs Assistant Associate Administrator Christyl Johnson of NASA HQ 

on the 40-inch Kevlar COPV testing. 

WSTF

ARC
30 NESC 2007 TECHNICAL UPDATE

TECHNICAL HIGHLIGHTS

SCIENCE

Entry, Descent, and Landing Repository and Analyses Task

Modeling of the EDL sequence for the proposed Mars 

Sample Return mission would benefit from a single 

comprehensive source of historical EDL data to improve modeling accuracy. 

Problem: An incorrect minimum current 

requirement for the cold temperature firing 

of NASA Standard Initiators (NSIs) on the 

Phoenix spacecraft was discovered. The circuit was designed to deliver 3.5 amps (with 

positive margin) whereas 5.0 amps is recommended at temperatures below -65°F. There 

were four pyrotechnic events of concern with 

the coldest event occurring at -173°F. Two of 

these events were mission critical. The Phoenix Project performed testing and analysis 

and determined that the design had sufficient 

current to fire the NSIs, although the recommended 5.0 amp current was not met.

NESC Contribution: The NESC was asked to 

review testing and analysis. A subset of 20 

units from the actual Phoenix NSI lot were 

tested and showed an “all fire” current limit 

of 4.1 amps with 90% system reliability using a 10 millisecond pulse current at -211°F. 

The NESC team found that the circuit analysis predicted, in worst case, the spacecraft circuitry would deliver a minimum current of 

4.47 amps (almost an amp of design margin). 

Additionally, the flight circuit uses a 20 millisecond pulse current (twice that required) 

and the worst case predicted temperature is 

-173°F. This results in positive margin in the 

current, time and temperature.

Results: The NESC team concurred with the 

Phoenix Project’s circuit analysis predicting 

sufficient current to fire the NSI’s. 

Problem: NASA and the Entry, Descent, 

and Landing (EDL) community lack a common repository of EDL data from previous 

Earth and planetary flight missions to aid in 

the design of future EDL systems. Recent 

missions to Mars will provide a wealth of information, however, much of the older data 

has been lost or is at risk of being unusable 

due to poor storage conditions. 

NESC Contribution: In response to this 

problem, the NESC is focusing on two aspects: to locate, collect, and digitize NASA 

technical and engineering EDL material and 

to develop a secure, web-based repository. 

Results: The EDL Repository is in the process of being created, and initial EDL material from a prioritized set of missions is 

being stored. Upon completion, the repository will be delivered (FY09-10) to a NASAselected Center for continued growth and 

maintenance.

NSI Firing Current Independent Review for Phoenix

Dozens of NSIs are used throughout the Phoenix 

spacecraft to initiate pyrotechnic events. The NESC 

agreed with the Project that the NSI firing circuit design was adequate.

JPL

JPL

TECHNICAL HIGHLIGHTS

SCIENCE
NESC 2007 TECHNICAL UPDATE 31

TECHNICAL HIGHLIGHTS

SCIENCE

Problem: After a failure encountered on the Dawn High 

Voltage Electronics Assembly 

(HVEA) during Assembly Test 

Launch Operations, the Dawn 

Project requested an independent NESC review of the available failure related data, subsequent activities and corrective 

actions taken by the project. 

The review was requested to ensure proper post failure actions 

were assigned and resolved as 

well as to provide additional 

recommendations for consideration, if applicable. 

NESC Contributions: After reviewing the available data related to the observed failure and 

working with the project team, 

the NESC Review Team determined that 

the cause of the Dawn HVEA failure was understood by the Dawn Project and occurred 

primarily as a result of operator procedural 

error that did not prepare the HVEA for 

Solar Array Simulator activation. The error 

resulted in high in-rush currents that were 

beyond the capability of the HVEA. 

Results: The Dawn Project implemented 

the HVEA repairs and actions recommended 

by the Review Team. Dawn was successfully 

launched in September, 2007.

Problem: A concern was raised regarding 

when the Dawn Mission Traveling Wave 

Tube Amplifier (TWTA) would be activated 

to establish the post-launch communications downlink. The mission plans called for 

TWTA activation one-hour after launch, but 

the spacecraft contractor typically requires a 

venting period of 24 hours due to potential 

failures that can occur from corona and/or 

breakdown of the high voltage microwave 

components in the TWTA. Breakdown can 

occur due to the presence of small physical 

gaps between conductors that carry a high 

radio frequency (RF) voltage in the presence 

of partial atmospheric pressures or outgas 

constituents. The NESC Chief Engineer at 

JPL requested an independent review of JPL 

TWTA venting analysis for Dawn.

NESC Contributions: The NESC conducted 

a thorough review of existing literature regarding RF breakdown in a low pressure environment to understand the state of knowledge regarding this phenomenon. All critical 

areas of the TWTA electronics were analyzed 

for adequacy of venting from the spacecraft 

during ascent to orbit to ensure that pressures at TWTA activation would be well 

below what is required for RF breakdown to 

occur.

Results: The NESC concurred with the JPL 

venting analysis which concluded that adequate margin existed to activate the TWTA 

in accordance with the mission time line 

and no evidence was found to support the 

24-hour waiting period. This finding was 

critical because a 24-hour delay in communications could have jeopardized mission 

success. Dawn was successfully launched in 

September, 2007. 

Lessons Learned: To mitigate risk on future missions, the activation of the communications equipment should be considered during spacecraft thermal vacuum test 

pump down to support validation of venting 

analysis and system performance.

Dawn Mission HVEA Failure Analysis Independent Review

Dawn Mission TWTA Venting Independent Assessment

JPL

The Dawn High Voltage 

Electronics Unit sustained 

damage due to excessive 

current during spacecraft 

testing. The NESC reviewed 

and concurred with the 

results of the JPL mishap 

investigation and made 

recommendations for the 

project’s consideration. 

The Dawn Mission required that the main communication system amplifier be activated soon after 

launch. The NESC reviewed and concurred with a 

JPL analysis that concluded that the system could be 

safely activated according to the mission timeline.

JPL
32 NESC 2007 TECHNICAL UPDATE

CENTER HIGHLIGHTS

3 2 NESC 2007 TECHNICAL UPDATE

CENTER HIGHLIGHTS

WSTF engineer Ralph Lucero examines a setup for 

nondestructive evaluation of a Kevlar composite 

overwrapped pressure vessel. 
NESC 2007 TECHNICAL UPDATE 3 33

CENTER HIGHLIGHTS

WSTF

The NESC efforts this year at Ames Research 

Center (ARC) included Aeroacoustic Noise 

Reduction for the Crew Exploration Vehicle 

and data mining methodology for the response 

team. Dr. Tina Panontin, the ARC Chief Engineer, was also named the NESC Chief Engineer at ARC and will perform both roles. The 

NASA Office of the Chief Engineer also named 

Dr. Cynthia Null, an NESC employee resident 

at ARC, as the NASA Technical Fellow for Human Factors.

Crew Exploration Vehicle (CEV) 

Aeroacoustic Noise Reduction

The NESC collaborated with the CEV Aerosciences Project Aerodynamic Testing Team to 

perform wind tunnel tests of three Alternate 

Launch Abort System (ALAS) configurations. 

The NESC examined the acoustic benefits 

from the alternate configurations. Empirical 

predictions showed that the baseline CEV 

Launch Abort System (LAS) would generate up 

to 172 dB local pressure fluctuations during a 

nominal ascent. For an ascent abort, the levels are expected to be as high as 17 dB. Protecting structure and systems from these very 

large pressure fluctuations is expensive and 

carries a significant weight penalty. The NESC 

effort led to an improved aerodynamic shape 

that has been adopted as the new baseline for 

the CEV. This new shape resulted in reducing 

the fluctuating pressure levels on the CEV with 

cost and weight savings for the CEV Program.

Data Mining Response Team

This year, the Data Mining Response Team 

established a data mining methodology; 

and solicited, reviewed, and started work 

on several activities. The team completed 

an analysis of the International Space Station (ISS) Problem Reporting and Corrective 

Action (PRACA) reports in support of a JSCled Orion spacecraft acceptance test study. 

The task was to gather and analyze historical failures for evidence of the effectiveness 

(or lack thereof) of system level acceptance 

testing for manned spacecraft. From an initial set of over 4000 reports, the team isolated 27 reports that had a direct bearing on 

potential Orion acceptance test issues.

The Data Mining in Aeronautics, Science, and 

Exploration Systems (DMASES2007) conference, sponsored by the NESC, Aeronautics 

Research Mission Directorate (ARMD) Integrated Vehicle Health Management (IVHM), and the 

Science Mission Directorate (SMD), provided 

the data mining community with an opportunity to share recent advances in data and text 

mining, machine learning, and statistics across 

the larger communities of engineers and scientists working in aeronautics, aerospace, and 

science.

NESC Awards

Mr. Ian Fernandez received the NESC Engineering Excellence Award for his contributions 

to the NESC Composite Crew Module Project.

AMES RESEARCH CENTER

NASA

“With access to experts within and outside of NASA, the NESC has contributed to the success of 

a number of Ames activities, from capture of Stardust aerothermal entry data, to peer review of 

CEV aeroscience efforts and aeroacoustics of the SOFIA aircraft modification. In similar fashion, 

Ames experts working in the NESC have brought their expertise to bear on Agency engineering 

challenges, in particular in the areas of TPS, composite design, data mining, and human factors. 

ARC is strongly committed to supporting future interactions with the NESC.”

— Dr. Tina L. Panontin, Ames Research Center Chief Engineer and NESC Chief Engineer 

Nate Burnside, 

ARC’s Principal 

Investigator of the 

Fluid Mechanics 

Laboratory, cleans

a nozzle after

the 50-AS testing 

was completed.

The baseline

605-068 LAV,

ALAS-2, and

ALAS-11 models

are in the

foreground.
34 NESC 2007 TECHNICAL UPDATE

CENTER HIGHLIGHTS

3 4 NESC 2007 TECHNICAL UPDATE

DRYDEN FLIGHT RESEARCH CENTER

Dryden Flight Research Center (DFRC) scientists and engineers have contributed 

to the NESC’s multi-discipline teams that are 

helping to address some of the Agency’s biggest challenges. The NESC has also supported 

NASA projects and programs at DFRC.

NESC Technical Discipline Team Support

DFRC has supported the NESC in the area of 

non-destructive evaluation (NDE), and structural health monitoring. That latter area includes 

an NESC workforce augmentation for a task 

supported by NASA’s Non Destructive Evaluation working group. Research is being conducted at a basic level to quantify and interpret 

the various contributions of the measurement 

response from fiber optic sensors embedded 

in composite overwrapped pressure vessels 

(COPV) when subjected to pressure loading. Testing of coupons with embedded fiber 

Bragg gratings parallel and perpendicular to 

the structural fiber direction is currently under way. DFRC is also supporting the NESC 

Loads and Dynamics Technical Discipline team 

through the efforts of Dr. Kajal K. Gupta, who 

has supported the NESC Ascent Loads Analysis system development. 

Stratospheric Observatory for Infrared 

Astronomy (SOFIA) Project Support

The SOFIA Project continues to be a key area 

of collaboration between the NESC and Dryden 

representatives. This year, DFRC supplied 

mechanical and avionic experts to support a 

SOFIA Cavity Door Drive System Independent 

Review Team. SOFIA team leaders asked for 

assistance in identifying experts in thermal insulation, an area in which the NESC made a 

contribution. In addition, SOFIA program managers requested that the NESC support other 

SOFIA reviews conducted this year. The reviews played a key role in a safe and successful initial flight test series and safe transition of 

the SOFIA aircraft to Dryden as well as in flight 

readiness for the next flight test phase.

NESC Awards

Several Dryden engineers who have supported 

NESC activities during past years were recognized with awards for their contributions. 

Dryden Associate Director for Operations Larry 

Schilling and Dryden NESC Chief Engineer 

Dr. James Stewart recently presented NESC 

awards to Vicki Regenie for the NESC Design, 

Development, Test and Evaluation Considerations for Robust and Human-Rated Spacecraft Assessment. Since gaining experience 

on this NESC team, she has been assigned as 

Dryden Deputy Exploration Mission Manager. 

Also recognized were Martin Trout, Doug Baker 

and William Brockett who received awards for 

their efforts on the Stardust Hypervelocity Entry Observing Campaign. Dr. Kajal Gupta received an NESC award for his support of NESC 

External Tank Liquid Hydrogen Tank Ice Frost 

Ramp Redesign.

DFRC

(Above left) Dryden Associate Director for Operations Larry Schilling presented an NESC achievement award to Vicki Regenie for efforts on the DDT&E assessment. (Above right) Dr. James Stewart presents an NESC Group Achievement award to Martin Trout for his 

efforts in the Stardust Hypervelocity Entry Observation Campaign.

DFRC

Dr. James 

Stewart

NESC’s Chief

Engineer at

DFRC

John Carter, DFRC 

SOFIA aircraft project 

manager (left) and 

NESC Chief Engineer 

at DFRC, Dr. James 

Stewart, discuss the 

SOFIA Cavity Door 

Drive System

Independent Review 

Team results and 

report that was

supported by the 

NESC.
NESC 2007 TECHNICAL UPDATE 3 55

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GLENN RESEARCH CENTER

The Glenn Research Center (GRC) engineering and scientific community participated 

in a wide range of NESC activities. The support from GRC consists of using matrixed GRC 

personnel and contractors as members of 

NESC assessment teams and NESC Technical 

Discipline Teams (TDTs). The NESC Chief Engineer (NCE) at Glenn represented the NESC 

as a member of the internal Engineering Management Council and major reviews of Center 

projects. The NCE provides GRC senior management status updates on NESC on-going 

activities.

Exploration Systems

The Glenn community has supported the near 

and far-term objectives of the Constellation 

Program through the NESC. GRC personnel 

planned and led sessions of the Lunar Dust 

Workshop held at Ames early this year and 

continue to perform key risk 

mitigation activities associated with lunar dust identified at the workshop. Other 

contributions included further evaluation and comparison of land and water 

landings for the Orion reentry, conceptual development of a composite crew 

module design and evaluation of thrust vector control architecture alternatives for the first-stage CLV. The NESC has 

worked along side the Ares I-X Upper Stage 

Simulator Project to independently assist in 

development of weld inspection criteria for the 

critically loaded welds in the structure. 

Space Operations

GRC supported the independent assessment 

of the Orbiter Wing Leading Edge Reinforced 

Carbon-Carbon (RCC) panel subsurface 

anomaly and the development of data to support flight rationale for STS-117. GRC scientist, Dr. Elizabeth Opila, was recognized for her 

contributions to this team. GRC has also participated on the tiger team assessment of the 

root cause and potential effects of a chipped 

gear tooth observed on a qualification unit of 

orbiter rudder/speed brake actuator. 

Additionally, GRC scientists have continued to 

play a particularly key role in establishing and 

communicating effective guidelines for development, test and use of composite pressure 

vessels for both the International Space Station and the Orbiter Project. GRC NDE team 

members including Dr. Don Roth are now summarizing NESC efforts over the last 3 years to 

develop and validate new NDE methods for the 

Space Shuttle external fuel tank foam.

Cross-Enterprise Proactive

Risk Reduction

Aerospace Battery Working Group: GRC 

leads a multi-Center team tasked to reduce 

and/or quantify some of the unknowns associated with battery life and performance in 

aerospace applications. The efforts of this 

team will lead to increased knowledge which 

will better inform designers and operators of 

aerospace flight systems which rely on battery 

technology. 

Computational NDE: Computational non-destructive evaluation is a promising advanced 

technology for analytically predicting “inspectability” of a test article based upon a CAD solid 

model geometry file. Glenn scientists will assist the validation of this technology for the 

Agency through initial funds provided by the 

NESC.

Design/Use Guidelines for Composite Pressure Vessels (CPVs): Dr. James Sutter of GRC 

and Dr. Lori Grimes-Ledesma of JPL together 

have provided leadership for the Agency’s 

Composite Pressure Vessel Working Group, 

which shares invaluable lessons learned, best 

practices and limitations associated with design and operating CPVs. The working group 

is a resources for all programs that are currently or are considering the use of these advanced 

vessels.

GRC

The GRC is designing and manufacturing the 11 Upper Stage Simulator segments for the Ares I-X flight demonstration. The largest segments are 10 feet high, 18 feet in diameter and will weigh up to 18,000 pounds.

Multiple chips were found in an Orbiter Rudder/Speed Brake qualification unit. (Inset) Backscattered electron micrograph showing general overall appearance of chipped region in topological mode.

GRC

Pick up caption from file.

Tooth length: 

1.670 inch for 

comparison

Smaller missing chip dimensions:

.055 inch long, .015 wide, .007 inch deep

Larger missing chip dimensions:

.07 inch long, .048 wide, .028 inch deep

Derrick Cheston

NESC’s Chief

Engineer at GRC
36 NESC 2007 TECHNICAL UPDATE

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3 6 NESC 2007 TECHNICAL UPDATE

GODDARD SPACE FLIGHT CENTER

The NESC continues to utilize the best talent 

from across the Agency to resolve NASA’s 

toughest issues. Goddard Space Flight Center 

(GSFC) personnel have contributed to numerous NESC assessments this year while GSFC 

projects and programs have also benefited 

from this same dynamic when they secured 

NESC support. The NASA Office of the Chief 

Engineer named the following as Technical Fellows: Mitchell Davis, Avionics; Cornelius Dennehy, Guidance, Navigation and Control; and 

Michael Aguilar for Software. All are NESC 

employees resident at GSFC. 

Technical Discipline Team Support

Goddard’s involvement in the NESC technical 

activities has primarily focused on the competency areas of GN&C and software. GSFC 

personnel serve as deputies to NASA Technical 

Fellows for Mechanical Systems and Mechanical Analysis who are resident other 

Centers.

Exploration Systems 

Support

Goddard’s competency in 

mission systems engineering has continued to evolve 

as an important NESC resource in support of the 

Constellation Program. GSFC personnel are 

now supporting Constellation-wide GN&C and 

Avionics architecture trade studies. GSFC is 

also currently hosting focused development 

activities on other NESC activities including 

the Composite Crew Module Pressure Vessel 

at GSFC and the Max Launch Abort System 

flight demonstration at Wallops Flight Facility. 

Space Operations Support

Goddard personnel were key participants in

numerous NESC activities in support of the 

Space Shuttle Program including the Rudder/

Speed Brake Chipped Gear Tooth and Power 

Drive Unit Motor Dry Film Lubrication Bolt Issue assessments, Fuel Cell Motor Two-Phase 

Operation evaluation, ET Ice Mitigation studies, and the Space Shuttle Tin Whiskers consultation. 

Goddard supported a variety of ISS activities 

including the Space Shuttle Power Transfer 

System risk evaluation, Rotor Joint Motor Controller Anomaly consultation, Control Moment 

Gyro Failure investigation, the use of Loctite®, 

S-Band Forward Link Anomaly, and Attitude 

Control Anomaly issues. Some of these problem-solving activities were performed in “realtime,” during the course of a mission. 

Science Mission Support

GSFC personnel have also led several NESC 

assessments in support of science missions, 

including the Conax Y-PCA Pyrovalve assessment for several science missions; and the 

Phoenix NASA Standard Initiator and Robotic 

Arm Brush Motor Failure reviews. 

Proactive Efforts

The NESC proactive work, intended to prevent 

problems by addressing issues common to 

multiple programs, has also benefited Goddard 

missions. The NESC has funded Field Programmable Gate Array reliability studies including an 

RTAX-S Risk Reduction program. The NESC is 

currently working on a DC/DC Converter users 

guide, supporting a NASA/Aerospace Flight 

Battery program, and studying the benefits of 

using Flight Force Measurements to Improve 

Coupled Loads determination and reduce design/qualification requirements.

NESC Awards

Dr. Daniel Polis received the NESC Director’s 

Award and Jeffrey Stewart received the NESC 

Leadership Award for their contributions to 

the NESC Composite Crew Module Project. 

Mr. Paul Guy received the NESC Engineering 

Excellence award for his contributions to the 

NESC independent review of the Phoenix Project. Mr. Robert Cherney accepted an NESC 

Group Achievement Award on behalf of the ISS 

to Shuttle Power Transfer Open PRACA Team.

Jeff Stewart/Mechanical Engineering Branch (left) and GSFC Director of Engineering Orlando Figueroa examine a 

model of the Composite Crew Module.

Optical Photograph of Tin Whiskers on Tin-Plated Beryllium-Copper Card Guides Removed from Space Shuttle 

Avionics Boxes in 2006.

Michael

Hagopian

NESC’s Chief

Engineer at 

GSFC

GSFC

GSFC
NESC 2007 TECHNICAL UPDATE 3 77

CENTER HIGHLIGHTS

JET PROPULSION LABORATORY

I

n 2007, JPL participated in numerous NESC 

studies for the Science, Exploration Systems 

and Space Operations Mission Directorates. 

Science Mission Support

JPL personnel engaged in independent NESC 

assessments of the Mars Phoenix Lander to 

evaluate an issue related to the firing of NASA 

Standard Initiators (NSIs) on the spacecraft. At 

cold temperatures the NSIs are recommended 

to use at least five amps as the current level 

with safety margin. Phoenix is supplying less 

current for several of the NSI circuits. The 

Phoenix Project testing and analysis shows 

that their levels are sufficient. The NESC concurred with the testing and analysis and supported the use of the NSI circuits as designed.

The Dawn Mission to orbit two of the solar 

systems largest asteroids, required analysis 

of its High Voltage Electronics 

Assembly (HVEA) which had 

a failure during thermal vacuum testing. Trouble shooting quickly identified several 

failed components. 

Evaluation of the repair approach and flightworthiness 

of the refurbished HVEA was 

conducted by the NESC and 

the system was accepted for flight. The Dawn 

Project also did an analysis that concluded 

that the Traveling Wave Tube Amplifier (TWTA) 

could be turned on within a very short time after separation from the launch vehicle. There 

was some residual concern that turning on a 

TWTA without waiting 24 hours could cause 

a failure due to insufficient venting of gasses 

from the chambers. The NESC independently 

reviewed the analysis to verify the assumptions and calculations and agreed with the 

JPL position. 

JPL has also been instrumental in the development of design and validation guidelines 

for next generation field programmable gate 

arrays used in many NASA and commercial 

spacecraft.

Exploration System Support 

Using expertise gained through Mars entry, 

descent and landing (EDL), JPL engineers and 

scientists are also leading a follow-on study to 

evaluate the existing NASA and new contractor CEV landing and recovery architectures. 

JPL personnel led the risk analysis for the team 

that quantified risks to the crew, vehicle and 

public. 

Space Operations Support

JPL continues to be engaged in the analysis 

of the long-term safety of COPVs. JPL is providing the joint leadership for the COPV working group sponsored by the NESC. JPL is also 

active in data mining and trending of existing 

problems. The Robotics Technical Discipline 

Team (TDT) led by JPL has also had 4 proactive proposals accepted to advance robotic 

exploration. The first of these led to a very successful Lunar Dust Workshop in January 2007. 

Sessions were conducted on issues in Human 

Health, Life Support, Mechanical Systems, and 

Research. The second task, DC/DC Converters, has developed a draft of guidelines for 

developers of power systems as well as test 

methodologies to be used. The last two, EDL 

Data Archiving and Wireless Avionics in Space 

are progressing well. 

NESC Awards

Mr. John Baker accepted an NESC Group 

Achievement Award on behalf of the NESC 

CEV Water Versus Land Landing Study Team.

• Heatshield

 Separation

• Heatshield

 Retained

LAND WATER

• Begin Using

 Altimeter

• Air bag

 Deployment

• Touchdown • Main Chute

 Disconnect

• Main Chute

 Disconnect

• Splashdown

R. Lloyd Keith

NESC’s Chief

Engineer at JPL

Graphic: NESC

JPL performed a risk assessment for land and water landing configuration options of an Orion Crew Module.

The Phoenix Pyrotechnic Initiation Unit sends current pulses of precise magnitude and duration to the 

NASA Standard Initiators on the Phoenix spacecraft 

to start numerous actions.

JPL
38 NESC 2007 TECHNICAL UPDATE

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3 8 NESC 2007 TECHNICAL UPDATE

JOHNSON SPACE CENTER

The NESC at the Johnson Space Center 

(JSC) continued to support the Space 

Shuttle Program (SSP), the International Space 

Station Program (ISS), and Constellation Program (CxP) during 2007. The NASA Office 

of the Chief Engineer named JSC engineers 

Henry (Hank) Rotter and Dr. Curtis Larsen as 

the NASA Technical Fellows. Mr. Rotter for 

Life Support/Thermal/Fluids and Dr. Larsen for 

Loads and Dynamics . Former NESC employees who have returned to, or become a part 

of the JSC team, include John McManamen, 

SSP Chief Engineer, Steve Labbe, CxP Chief 

Engineer, Julie Kramer-White, Crew Exploration 

Vehicle (CEV) Chief Engineer; Brian Muirhead, 

Cx Program Architecture Office lead, Steve 

Hawley Astromaterials Chief, and Jay Legett as 

the ISS Systems Engineer.

Space Operations Support

The NESC supported the SSP through a number of assessments. Orbiter-specific analyses 

included: development of alternate Non-Destructive Evaluation (NDE) technology for inspection of the orbiters’ leading edge Reinforced Carbon-Carbon panels; working with 

the Orbiter Project team to investigate/resolve 

issue of chipped gear teeth found in the rudder/

speedbrake actuator; independent analysis following loss of phase A power on an Orbiter fuel 

cell pump for the STS-115 mission. External 

Tank (ET) — specific support included: support 

to the Ice Frost Ramp Redesign Team; participation with the ET Team in foam repair assessment engineering; developing a foam impact 

prediction algorithm of ascent debris release 

from the ET, debris transport, 

and orbiter thermal protection 

system impacts in order to 

perform an independent risk 

assessment; participated in 

the development and testing 

of the Shuttle Ice Liberation 

Coating which has shown 

reduction of ice adhesive 

strength on aluminum, foam, 

Kapton tape and film, and on Fire-X paint. 

The NESC also conducted an assessment of 

NDE options for the Crawler transporter shoes 

which have experienced cracking due to casting voids and associated slag inclusion. The 

NESC provided support to the ISS Program in 

several areas. The NESC investigated specific 

subsystem issues including: the effect of Solar Array Mast longeron shadowing, including 

thermal-vacuum testing at JPL; supported ISS 

Team to understand cause of the Rotary Joint 

Motor Controller failure in the robotic arm; 

investigated electrical nuisance trips of the 

Space Shuttle to ISS Power Transfer System 

and supported further study of the potential 

hazards associated with Control Moment Gyro 

bearing failure. 

More general ISS investigations included: assessment of the sensitivity of LoctiteTM performance to fastener variables including diameter, thread class, thread finish, cleaning, 

primer, preload, cure, joint type, material and 

type of Loctite; support for ISS coolant chemistry testing and analyses in preparation for 

systems activation, and finally, established a 

multi-disciplinary team to address Composite 

Overwrapped Pressure Vessel issues, specifications, design practices, manufacturing, testing, and use for ISS, including the SSP, and 

future vehicles.

Exploration Systems Support

JSC employees engaged in numerous NESC 

assessments in support of CxP, covering a 

broad range of topics. CEV-related support to 

the NESC CEV Composite Crew Module Team; 

development of Alternate Launch Abort System concepts for CEV designed to reduce ascent drag with goal to increase weight to orbit 

and evaluation of injury/loss-of-crew risk factors for CEV water and land landing designs. 

Ares support included: independent study to 

identify minimum allowable flaw size in vicinity of structural welds on the new Ares launch 

vehicle utilizing the loads cycle spectrum to 

predict crack growth for assumed structural 

flaws; assessed the knockdown factor for 

structural shell buckling of booster walls to 

assess conservatism; conducted independent 

assessment of the NASA Plum Brook Facility 

for J2X engine testing, and supported the assessment of safe separation storage distances 

for the additional solid rocket segments at KSC 

required for the CxP lunar and Mars missions.

NESC Awards

Mr. Christopher Cerimele and Mr. Joel Broome 

received the NESC Engineering Excellence for 

their contributions to the NESC CEV. Water 

versus Land Landing Study. Dr. Eugene Ungar received the NESC Engineering Excellence 

Award for his contributions to various NESC efforts on the Space Shuttle External Tank.

The International Space Station (ISS) seen from the Space Shuttle Endeavour on STS-118. The NESC has supported several recent activities on the ISS.

NASA

Dave Hamilton

NESC’s Chief

Engineer at JSC

 
NESC 2007 TECHNICAL UPDATE 3 99

CENTER HIGHLIGHTS

KENNEDY SPACE CENTER

The Kennedy Space Center (KSC) continues 

to provide excellent support and expertise 

to a wide variety of NESC assessments and 

testing. The NESC team was well supported by 

more than 50 KSC civil servants and contractors of various disciplines who were active in 

NESC assessments and studies this year. Also, 

26 NASA personnel at KSC are standing members of the NESC’s Technical Discipline Teams. 

These discipline expert teams are the primary 

workforce the NESC calls upon when performing assessments and studies.

Space Operations Support

KSC researchers continued to support the 

NESC Shuttle Ice Mitigation assessment. This 

assessment is developing and testing a new 

compound called Shuttle Ice 

Liberation Coating which has 

been demonstrated to reduce 

the adhesive strength of ice on 

aluminum, foam, and Kapton® 

material. The Space Shuttle 

Program will begin qualification 

testing of this material for use 

on the Space Shuttle as early 

as next year.

KSC engineers provided assistance to the NESC in an important circuit analysis and circuit 

simulation for two key International Space Station issues as a member of the NESC Avionics 

& Electrical Technical Discipline Team. 

Exploration Systems Support

In anticipation of increased amounts of solid 

propellant segment processing in the Vehicle 

Assembly Building (VAB) during the later Constellation Program campaigns, the NESC is 

partnering with KSC to assess safe separation 

distances surrounding the VAB. The NESC is 

modeling the ignition characteristics of the propellant and motor segments within the VAB and 

its internal structure while KSC is instrumenting and collecting solid rocket motor test data 

to anchor the models. Multiple NASA Centers, 

other government agencies and industry are 

partnering to perform this assessment. 

In January 2007, the NESC sponsored a Lunar 

Dust Workshop to gather leading experts from 

around the country and discuss the potential 

technical risks and mitigation strategies for 

humans, spacecraft, and equipment working in 

the lunar environment. KSC was well represented by several researchers performing innovative work in this field. 

Science Mission Support

The NESC is actively working with KSC’s 

Launch Service Program on a Flight Force 

Measurement project. This assessment will 

use flight measured strain data to resolve the 

actual flight forces at the spacecraft interface. 

The measurement system will be flown on the 

GLAST Mission. KSC personnel also contributed to the Conax Pyrotechnic Valve failure 

assessment.

NASA

NASA 

Joycelyn Harrison of LaRC Advanced Materials and Processing and Charles Stevenson of KSC Engineering discuss 

the practical application of SILC on the umbilical that feeds liquid hydrogen from the External Tank to the Orbiter’s 

Main Propulsion System. Stephen

Minute

NESC’s Chief

Engineer at 

KSC

VAB Burn Simulation

The NESC is assisting KSC and the 

Constellation Program by studying 

the possible effects of multiple 

Solid Rocket Motor segments 

burning in the VAB. The study is 

assessing the probability of an 

ignition event and the safe distance 

for personnel. The simulation 

shows the isosurface of a plume 

from burning segments in the VAB 

52 seconds after ignition.

Graphic: NESC
40 NESC 2007 TECHNICAL UPDATE

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4 0 NESC 2007 TECHNICAL UPDATE

Langley Research Center (LaRC) scientists 

and engineers continue to assist in the 

NESC mission in support of the Agency’s highrisk programs and projects. LaRC has contributed technical expertise in areas of structures, 

materials, nondestructive evaluation (NDE), 

flight sciences, fabrication technology, loads 

and dynamics, computational fluid dynamics, 

mechanisms, guidance navigations and control, and avionics. LaRC continues to be the 

home Center for the NESC’s’ Directors Office, 

Systems Engineering Office and the Management and Technical Support Office. The NASA 

Office of the Chief Engineer also named Drs. 

Robert Piascik, William Prosser, Ivatury Raju 

and David Schuster as NASA Technical Fellows for Materials, Nondestructive Evaluation, 

Structures and Aerosciences respectively. 

They are resident at LaRC.

Space Operations Support

The NESC is working with the Orbiter Project to 

discover the root cause of the anomalies in the 

orbiters’ Reinforced Carbon 

Carbon (RCC) wing leading 

edge and to develop improved 

nondestructive evaluation 

(NDE) methods for inspecting 

the RCC. Thermography NDE 

systems from LaRC’s Nondestructive Evaluation Sciences 

Branch (NESB) were used in 

an effort to identify regions 

where degradation of the interface between the silicon 

carbide (SiC) coating and the RCC substrate 

may have occurred. Microfocus Computed 

Tomography (CT) X-ray systems were then 

used to confirm the presence of defects such 

as delaminations at the silicon carbide coating 

interfaces in these RCC materials. Additionally, the computational facilities of NESB were 

used to analyze thermography NDE data previously acquired at KSC for all Space Shuttle 

RCC panels to determine if similar defects are 

present on RCC flight panels. Members of the 

NESC’s Materials, Structures and NDE Technical Discipline Teams (TDTs) as well as the 

Technical Fellows who lead these TDTs have 

been involved with this effort.

Exploration Systems Support

LaRC personnel have also been members of 

NESC technical teams who are developing 

advanced technologies for consideration and 

possible use by the Constellation Program. 

The Alternate Launch Abort Systems (ALAS) 

study sponsored by the NESC evaluated the 

structural, thermal, acoustic, aerodynamic, 

aerothermodynamic, stability and control, and 

mission performance effects for an integrated 

launch abort motor and load carrying shroud 

for the Orion Crew Module. Aeroheating tests 

were performed using the LaRC Hypersonic 

Materials Environmental Test System arcjet to 

study material exposure effects from the launch 

abort motor plume. LaRC’s fabrication experts 

developed the wind tunnel models used in the 

ALAS study. These efforts led to the adoption 

of ALAS as part of the Orion design. LaRC’s 

Geometry Laboratory (GEOLAB) provided advanced capabilities to support research applications that require surface and grids for 

numerical simulations in Computational Fluid 

Dynamics and Computational Structural Mechanics. The NESC has used GEOLAB extensively for geometry modeling and grid generation for the ALAS and another alternate launch

abort system referred to as the Max Launch 

Abort System (MLAS). 

NESC Awards

This year four LaRC researchers received 

NESC Engineering Excellence Awards. Dr. 

Edwin Fasanella was recognized for his contributions to the NESC CEV Water versus Land 

Landing Study. Mr. Ray Rhew was recognized for his efforts on the NESC Solid Rocket 

Booster Roll Torque Study. Dr. Stephen Scotti 

was recognized for his contribution to the 

NESC ALAS Study and also accepted an 

NESC Group Achievement Award on behalf of 

the ALAS Team. Mr. Jeffrey Seebo was recognized his contributions to the NESC NDE of 

the Space Shuttle External Tank Thermal Protection System.

LANGLEY RESEARCH CENTER

Dr. William Prosser, NASA Technical Fellow for Nondestructive Evaluation (left) and Dr. William Winfree review 

line scan thermographic data from an orbiter WLE RCC specimen. The new line scan data analysis methodology, 

developed by Dr. Winfree for the NESC, has proven invaluable at identifying imperfections under the SiC coating 

that provides oxidation protection for the RCC during re-entry.

Dr. Michael

Gilbert

NESC’s Chief

Engineer at 

LaRC

NESC

(From left) Dr. David Schuster, NASA Technical Fellow for Aerosciences, Dr. Charles Camarda, NESC Deputy Director for Advanced Projects, and Dr. Stephen Scotti, ALAS Study Lead, examine the shape of the ALAS wind tunnel 

model. LaRC personnel made up the majority of the NESC’s ALAS Team.

NESC
NESC 2007 TECHNICAL UPDATE 4 11

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MARSHALL SPACE FLIGHT CENTER

Marshall Space Flight Center (MSFC) employees have been supporting major 

NESC efforts across a broad range of activities. In addition, the NASA Office of the Chief 

Engineer also named Mr. George Hopson, resident at MSFC, as the NASA Technical Fellow 

for Propulsion.

Space Operations Support

MSFC personnel continued in 2007 to participate in NESC assessments of flight and operations hardware for the Space Shuttle Program. Two of the largest efforts were in the 

Nondestructive Evaluation discipline. When a 

hail storm struck the vehicle on the launch pad 

prior to STS-117 there was extensive surface 

damage to the External Tank (ET). The NESC requested that thermography be used to inspect 

the nose cone. This was a process similar to 

that which was used to certify the hardware. 

Removing the nose cone was not feasible so 

a new technique was developed and tested at 

MSFC, showing that damage that might lead 

to a material failure could be detected. The 

ET was inspected in place at 

KSC and determined to be 

flight ready. 

Another NDE assessment 

sponsored by the NESC was 

the development of a Phased 

Array Ultrasonic Technique 

for inspecting the shoes of 

the Crawler Transporter used 

to move the mated vehicle 

to the launch pad at KSC. 

Working with LaRC and KSC, MSFC personnel developed this technique and the system 

to perform the inspections. This enabled detection of cracks or voids in the shoes, reducing the likelihood of failure while in transit to 

the launch pad. 

As members of the NESC Technical Discipline 

Teams, MSFC engineers engage in other activities concerning the Space Shuttle and the 

International Space Station (ISS). Some additional contributions were in maturing NDE 

techniques for the ET Thermal Protection System and in the use of these methods to help 

quantify risk on the Ice Frost Ramp redesign, 

in fracture analysis of the pressure shell welds 

on ISS pressure vessels, and for the Orbiter 

rudder/speed brake bolt test.

Exploration Systems Support

The NESC efforts that began on the Space 

Shuttle Program have application to Ares and 

Orion. This includes development and certification of new NDE techniques. MSFC engineers are engaged in the NESC Composite 

Crew Module activity, in which a multi-center 

team is developing an Agency-wide design 

expertise for composite habitable spacecraft. This effort is intended to strengthen the 

Agency’s experience in designing, analyzing, 

building, and testing composite structures and 

pressure vessels. Fabrication of all building 

block test elements has begun at MSFC in the 

National Center for Manufacturing facility. 

MSFC engineers are contributing to the NESC 

working group for Composite Pressure Vessels in the area of materials, manufacturing, inspection, and damage tolerance. Information 

gained is being directly inserted into projects 

such as the First Stage and Upper Stage for 

Ares and the Launch Abort System on Orion.

A major upcoming effort for this group is an 

assessment of the state-of-the-art in composite cryogenic tanks. MSFC engineers also 

worked, at the request of the NESC, on several 

other projects in support of the Science Mission Directorate. One of the tasks was in assessing damage done during acoustic testing 

to Aquarius hardware.

Thomas DeLay, is supporting the NESC as a member of the Composite Pressure Vessel Working Group. In this 

image, he is fabricating a series of lined and unlined composite test vessels used to understand the performance 

of fibers and matrix resins.

Dr. Charles

Schafer

NESC’s Chief

Engineer at

MSFC

MSFC

(From left) Larry Pelham (MSFC), Dr. Dan Polis 

(GSFC), and Ron Schmidt (Lockheed Martin), fabricate 

Pi joints at MSFC that will be machined into pull-off 

and shear test coupons in support of the NESC Composite Crew Module Project.

MSFC
42 NESC 2007 TECHNICAL UPDATE

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4 2 NESC 2007 TECHNICAL UPDATE

STENNIS SPACE CENTER

This year the Stennis Space Center (SSC) 

has continued to support NESC assessments with propulsion expertise in several 

areas in support of the Exploration Systems 

Mission Directorate (ESMD) efforts.

Since 1989, plume diagnostic engineers from 

the (SSC) technology laboratory have collected and analyzed more than three million 

data seconds of plume data from a variety of 

rocket engines. SSC is using this experience 

to support the NESC in the data collection and 

analysis efforts necessary to validate models 

of Solid Rocket Motor (SRM) Quantity-Distance Siting for the Vehicle Assembly Building 

(VAB) at Kennedy Space Center. The goal of the study is to 

determine the maximum number of SRM segments that can 

be safely stored in the VAB 

since the Ares boosters will 

use even more segments than 

the Space Shuttle. 

Traditional siting methodology assumes instantaneous 

combustion of all available 

propellant. However, analysis of the data acquired by SSC in August 2006 during an openair disposal of a Titan IV segment proves the 

energy release, even for a single segment with 

a compromised motor case, is distributed over 

time.

The current effort is to establish validated 

physical models that accurately represent the 

conditions resulting from a fire involving Solid 

Rocket Motors in the VAB. SSC collected heat 

flux data from the plume of FSM-14 (Flight 

Support Motor) at ATK on May 24, 2007. 

Through NESC funding, SSC also supports 

the Agency-wide development and implementation of NASA Technical Standard, “NASASTD-7009 Standard for Models and Simulations.” The goal of this standard is “to ensure 

that the credibility of the results from models 

and simulations (M&S) is properly conveyed 

to those making critical decisions.” This is an 

important effort because SSC is also providing Computational Fluid Dynamics modeling of 

several engine test facilities in support of the 

Ares I and Ares V launch vehicles.

A uniformly applied standard is necessary to 

ensure the information gained through M&S 

are properly understood. SSC tested the usability of the M&S standard through a pilot 

study of the Computational Fluid Dynamics 

simulations as part of the Methane Technology 

Testbed Program. Using the credibility scale in 

the standard, the results of the M&S were evaluated to determine the extent to which project 

requirements were met. 

In the near term, SSC will conduct subscale 

testing to support the design of the new A3 

test stand. The test stand will be used to conduct altitude simulation tests for the Upper 

Stage J2X engine. The NESC involvement will 

include development of Computational Fluid 

Dynamics models for the subscale diffuser, as 

well as acoustical models to assess test stand 

and support facilities impacts. SSC’s support 

of ESMD, in the areas of propulsion testing and 

M&S, will continue well into the future.

Freddie 

Douglas

NESC’s Chief

Engineer at 

SSC

SSC

“From my personal experiences in the NESC, I was always impressed with the depth and breadth of technical 

expertise the organization could bring to bear on some of NASA’s toughest technical problems. Here at Stennis, 

I continue to see the contributions NESC makes across all of NASA’s activities.

 — Dr. Richard Gilbrech - Associate Administrator for Exploration Systems and former Director of the SSC

ATK

The plume diagnostic engineers at SSC measured 

the heat flux from the plume of a Space Shuttle solid 

rocket motor during a test firing.

SSC modeled the operation of methane powered engine to support development of NASA Standard 7009 

Standard for Models and Simulations
NESC 2007 TECHNICAL UPDATE 4 33

CENTER HIGHLIGHTS

WHITE SANDS TEST FACILITY

The NESC has continued to utilize the White 

Sands Test Facility (WSTF) in assisting 

important NASA projects and issues. These 

primarily assisted the Space Operations, Science, and Exploration Mission Directorates 

and addressed issues involving pyrovalves, 

many different aspects of Composite Overwrapped Pressure Vessels (COPVs), Orbiter 

ice mitigation, chemical oxygen generation, 

and special Nondestructive Evaluation (NDE) 

techniques development.

Space Science Support 

WSTF personnel collaborated with personnel 

from other NASA Centers, the Jet Propulsion 

Laboratory, and Lockheed-Martin to help the 

NESC investigate five ground test failures of 

pyrotechnically-operated valves. Although 

none of the failures occurred in actual flight, 

the investigation was driven by serious concerns for several NASA spacecraft.

The investigation set a challenging goal of understanding the dynamic interactions between 

the initiators, the booster charge, and the YPCA. This required measuring high pressures 

and temperatures inside a very small enclosure in microsecond time frames. These requirements led to the development of several 

innovative measurement techniques and specialized test fixtures.

The fixtures often incorporated sapphire 

lens to allow temperatures to be measured 

by high speed optical sensors (pyrometers) 

as high dynamic pressures were measured. 

High speed video cameras (capable of up to 

200,000 frames per sec) also captured video 

through the lens and were also used to measure flame front and particle velocities 

in open air. 

To evaluate booster ignition temperatures, lasers were often used to rapidly 

heat Pyrovalve booster charges while 

the optical pyrometers measured the 

ignition temperature. Other specialized laboratory equipment such as 

X-ray Computed Tomography was 

used post-test to accomplish analyses. This technique allowed erosion 

and melting patterns inside actual Y-PCAs to 

be characterized without sectioning.

Space Operations and Exploration 

WSTF personnel continued to assist the NESC 

by supporting Carbon and Kevlar COPV efforts for major NASA programs. WSTF also 

provided consultation on Constellation Program COPV designs and is performing data 

collection and establishing a data library for 

the newly formed NESC Composite Pressure 

Vessel Working group.

WSTF is supporting an investigation into potential failure modes of chemical oxygen generators, specifically the CAN-26 model which 

was chosen for the flight qualified BOXYCAN 

oxygen backup system for ISS. Though not 

flown, this system is representative of all operational SCOG hardware. A recent explosion 

aboard a submarine of the British Royal Navy 

was traced to a CAN-26 (possibly defective, 

possible contaminated). WSTF is currently 

working to understand and reproduce the 

catastrophic failure. 

The WSTF test team continued to support the 

NESC investigation of potential solutions to reduce the risk posed by ice 

formation in the Space Shuttle LOX 

feedline bracket areas. A test fixture, 

known as the LOX Feedline Articulation Restraint Simulator, was designed and built at WSTF to simulate 

the geometry and temperatures of the 

bracket arm area during fill, de-tanking and launch scenarios. The fixture 

was used to test several versions of 

the polyimide flexible foam, a solution to mitigating ice formation in the gap between the 

feedline bracket arm and the feedline itself.

WSTF

WSTF WSTF

Dave Hamilton

NESC’s Chief

Engineer at JSC

for WSTF

Engineer Tom Hanson compares a fabricated test fixture with his original CAD design for pyrotechnic valve testing conducted at WSTF.

WSTF Engineer Tim Gallus aligns the laser used to 

ignite pyrotechnic valve booster charges.

WSTF Engineers John Haas and Larry Starritt examine a CAN-26 chemical oxygen generator. 
44 NESC 2007 TECHNICAL UPDATE

NESC HONOR AWARDS

(From left) Jeffrey Stewart (GSFC); Jeffrey Seebo (LaRC); John Baker (JPL); Ray Rhew (LaRC); Ralph Roe (NESC Director/Presenter); Derrick Cheston 

(GRC); Delmar Foster (United Space Alliance); Michael Hagopian (GSFC); Christopher Hansen (JSC); David Watson (ATK Space); Ian Fernandez (ARC); Dr. 

Daniel Polis (GSFC); James Jeans (Genesis Engineering); Paul Guy (GSFC); Dr. Eugene Ungar (JSC); Robert Cherney (GSFC); Dr. Edwin Fasanella (LaRC); 

Dr. Stephen Scotti (LaRC); Tim Wilson (NESC Deputy Director/Presenter); Kenneth Cameron (NESC Chief Astronaut/Presenter). Not pictured: Joel Broome 

(JSC); Christopher Cerimele (JSC). 

NESC Director’s Award

Dr. Daniel L. Polis

In recognition of technical excellence to the Composite Crew 

Module Team through practical 

methodology and approach for 

managing structural reliability through material properties, building block testing, and 

factors of safety for composite 

spacecraft structures.

NESC Leadership Award

Christopher P. Hansen

In recognition of outstanding 

leadership providing engineering 

excellence, solving complex engineering problems, and building 

team consensus for the Composite Crew Module Project.

NESC Honor Awards are part of an incentive and recognition program. They are given 

each year to NASA Center employees, industry 

representatives, and other stakeholders for their 

efforts and achievements in the areas of engineering, leadership, teamwork, and communication.

These honorary awards formally identify individuals and groups who have made outstanding 

contributions to the NESC’s mission and who 

demonstrate the following characteristics:

• Engineering and technical excellence

• Fostering an open environment

NESC Director’s Award

Honors individuals who take personal accountability and ownership in initiating 

clear and open communication on diverse 

and controversial issues. A key component of 

this award is based on the process of challenging engineering truths.

NESC Engineering Excellence Award

Honors individual accomplishments of 

NESC job-related tasks of such magnitude 

and merit as to deserve special recognition.

NESC Leadership Award

Honors individuals who have had a pronounced effect upon the technical activities 

of the NESC.

NESC Group Achievement Award

Honors a team of employees comprised of 

government and non-government personnel. 

The award is in recognition of outstanding accomplishment through the coordination of individual efforts that have contributed substantially to the success of the NESC’s mission.

The Four NESC Honor Award Categories

NESC

Awards continued on next page

The NESC Honors Engineering Excellence in Williamsburg

Honoree’s List
NESC 2007 TECHNICAL UPDATE 45

NESC HONOR AWARDS

Jeffrey W. Stewart

In recognition of outstanding 

leadership in establishing the organization structure of the composite crew module team, and 

for designing and implementing 

the Composite Crew Module 

Concurrent Design Center at 

Goddard Space Flight Center.

David B. Watson

In recognition of outstanding 

leadership coordinating the 

work of 16 designers and analysts from across the country resulting in a mature Preliminary 

Design Review for the Composite Crew Module Project.

NESC Engineering

Excellence Award

Joel M. Broome

In recognition of exceptional 

technical support for Crew Exploration Vehicle (CEV) entry, 

descent, and pad abort trajectory 

analyses in support of the CEV 

Water vs. Land Landing Risk Assessment.

Christopher J. Cerimele

In recognition of exceptional 

technical support for the development of an entry and descent 

trajectory analysis methodology 

that enabled identification of potential risks to the Crew Exploration Vehicle (CEV) flight crew.

Dr. Edwin L. Fasanella

In recognition of exceptional 

technical support for investigations into the Crew Exploration 

Vehicle (CEV) Crew Module and 

Apollo Command Module crew 

injury analysis and survivability 

during water and land landings.

Ian M. Fernandez

In recognition of engineering 

excellence in the development of 

an innovative load sharing floor 

design on the Composite Crew 

Module Project.

Delmar C. Foster

In recognition of technical expertise and outstanding proactive support in establishing the 

processes and techniques for 

SAS software utilization within 

the Data Mining and Trending 

Working Group.

Paul D. Guy

In recognition of outstanding 

technical leadership of the independent review of the NASA 

Standard Initiator (NSI) for the 

Phoenix Project.

James W. Jeans

In recognition of engineering 

excellence in rapidly and accurately building an engineering 

analysis model of the Composite 

Crew Module Project.

Ray D. Rhew

In recognition of innovative 

incorporation of system calibration methodologies into the 

quantification of the internal 

roll torque contributions associated with segmented solid rocket 

motor firings.

Dr. Stephen J. Scotti

In recognition of engineering excellence in the innovative design 

of an Alternate Launch Abort 

System configuration.

Jeffrey P. Seebo

In recognition of outstanding 

technical support of NESC 

Nondestructive Evaluation for 

the External Tank Thermal 

Protection System Team.

Dr. Eugene K. Ungar

In recognition of outstanding 

support to numerous NESC 

assessments pertaining to the 

Shuttle External Tank.

NESC Group

Achievement Award

Crew Exploration Vehicle 

Water Versus Land Landing

Assessment Team

In recognition of technical excellence in the investigation into the 

merits of water versus land landings for the Crew Exploration 

Vehicle (award accepted by John 

Baker on behalf of the team).

Crew Exploration Vehicle Alternate Launch Abort System 

(ALAS) Team

In recognition of outstanding 

efforts in developing and evaluating a design solution for an 

Alternate Launch Abort System 

(ALAS) for the Crew Exploration Vehicle (award accepted by 

Dr. Stephen Scotti on behalf of 

the team).

Shuttle Power Transfer System 

(SSPTS) Open PRACA Risk 

Evaluation Team

In recognition of outstanding 

contributions to the International Space Station to Shuttle 

Power Transfer System Open 

PRACA Risk Evaluation (award 

accepted by Robert Cherney on 

behalf of the team).

NESC Special Recognition

Derrick J. Cheston

In recognition of outstanding 

leadership and engineering excellence as the NASA Engineering and Safety Center’s Chief 

Engineer at Glenn Research 

Center.

Michael Hagopian

In recognition of outstanding 

leadership and engineering excellence as the NASA Engineering and Safety Center’s Chief 

Engineer at Goddard Space 

Flight Center.

Derrick Cheston, NESC Chief Engineer at GRC (center) receives an NESC Engineering Excellence Award from NESC Deputy Director for Safety and NESC Chief Astronaut, Kenneth Cameron (left), and NESC Director Ralph Roe, Jr. (right).

Michael Hagopian, NESC Chief Engineer at GSFC (center) receives an NESC Engineering Excellence Award from NESC Deputy Director for Safety and NESC Chief Astronaut, Kenneth Cameron (left), and NESC Director Ralph Roe, Jr. (right).

NESC

NESC
46 NESC 2007 TECHNICAL UPDATE

BIOGRAPHIES

Dr. Daniel Winterhalter

NESC Chief Scientist

Dr. Winterhalter is the NESC’s Chief Scientist and is 

resident at the Jet Propulsion Laboratory (JPL). Dr. 

Winterhalter has over 29 years of experience as a research scientist at JPL. His research interests include 

the spatial evolution of the solar wind into the outer reaches of the heliosphere, as well as its interaction with and influence on planetary environments. In addition, as a member of several flight teams, he has 

been intimately involved with the planning, launching, and operating of 

complex spacecraft and space science missions.

Ralph R. Roe, Jr.

NESC Director

Mr. Ralph R. Roe, Jr. serves as the NESC’s Director at 

Langley Research Center (LaRC). Mr. Roe has over 24 

years of experience in human space flight program management, technical management, and test engineering. 

Mr. Roe previously held several key positions in the Space Shuttle Program, including Vehicle Engineering Manager, Launch Director, and 

Kennedy Space Center Engineering Director.

Kenneth D. Cameron

NESC Deputy Director for Safety

and NESC Chief Astronaut

Mr. Kenneth D. Cameron is an Astronaut and serves 

a dual role in the NESC as the Deputy Director for 

Safety and the Chief Astronaut and is resident at the 

Johnson Space Center (JSC). Mr. Cameron was formerly an NESC 

Principal Engineer serving at Langley Research Center (LaRC).

Mr. Cameron joined the NESC after 7 years in private industry and 

a career in the U.S. Marine Corps. Mr. Cameron has over 27 years of 

experience in aeronautics and astronautics as a Naval Aviator, Test Pilot, 

and Astronaut, and is the veteran of three Space Shuttle missions: Pilot 

of STS-37 and Commander of STS-56 and STS-74.

Timmy R. Wilson

NESC Deputy Director

Mr. Timmy R. Wilson is the NESC’s Deputy Director. 

Mr. Wilson was formerly the NESC’s Chief Engineer at 

Kennedy Space Center (KSC). Prior to joining the NESC, 

Mr. Wilson served as Deputy Chief Engineer for Space 

Shuttle Processing at KSC. Mr. Wilson has over 26 years of engineering and 

management experience supporting the Space Shuttle Program.

Dr. Charles J. Camarda

NESC Deputy Director

for Advanced Projects

Dr. Charles J. Camarda is the Deputy Director for Advanced Projects and is resident at the Johnson Space 

Center. Dr. Camarda began his NASA career in 1974 

as a thermal structures research scientist at the Langley Research Center. 

He has over 33 years of technical and management experience in thermal structures and materials research for aircraft, spacecraft, and space 

launch vehicles. He was selected as an astronaut candidate in 1996, and 

flew aboard STS-114 as a Mission Specialist. 

LEADERSHIP CORE TEAM

Dawn M. Schaible

Manager, Systems Engineering Office

Ms. Dawn M. Schaible is Manager of the NESC Systems 

Engineering Office at Langley Research Center (LaRC). 

Prior to joining the NESC, Ms. Schaible worked in the 

International Space Station/Payload Processing Directorate at Kennedy Space Center. Ms. Schaible has over 20 years of experience in systems engineering, integration, and ground processing for the 

Space Shuttle and International Space Station Programs.

Patricia L. Dunnington

Manager, Management

and Technical Support Office

Ms. Patricia L. Dunnington is the Manager of the Management and Technical Support Office at Langley Research Center (LaRC). Prior to joining the NESC, Ms. 

Dunnington served as the Agency’s Chief Information Officer (CIO) at 

NASA Headquarters. Ms. Dunnington began her NASA career in 1982 

as a Presidential Management Intern. Ms. Dunnington has held several 

positions in the Agency, including the Agency Deputy CIO and the CIO 

for the NASA Langley Research Center. 
NESC 2007 TECHNICAL UPDATE 47

BIOGRAPHIES

Wayne R. Frazier

NASA Headquarters Senior SMA

Integration Manager

Mr. Wayne R. Frazier currently serves as Senior Safety 

and Mission Assurance Manager in the Office of Safety 

and Mission Assurance (OSMA), where he is assigned as 

the Liaison Officer to the NESC, the Office of the Chief Engineer, the 

Software Independent Verification and Validation Facility in West Virginia, and other remote activities of OSMA. He was formerly Manager of 

System Safety in the OSMA at NASA Headquarters and has over 32 years 

of experience in System Safety, Propulsion and Explosive Safety, Mishap 

Investigation, Range Safety, Pressure Systems, Crane Safety and Orbital 

Debris Mitigation.

NASA HEADQUARTERS LIAISON

Steven J. Gentz

NESC Principal Engineer

Mr. Steven J. Gentz is a Principal Engineer with the 

NESC at Langley Research Center (LaRC). Mr. Gentz 

joined the NESC from the Marshall Space Flight Center with over 24 years of experience involving numerous 

NASA, Department of Defense, and industry failure analyses and incident 

investigations, including Challenger, Columbia, Tethered Satellite System, 

and the TWA 800 Accident Investigations.

Clinton H. Cragg

NESC Principal Engineer

Mr. Clinton H. Cragg is a Principal Engineer with the 

NESC at Langley Research Center (LaRC). Mr. Cragg 

came to the NESC after retiring from the U.S. Navy. Mr. 

Cragg served as the Commanding Officer of the U.S.S. 

Ohio and later as the Chief of Current operations, U.S. European Command. Mr. Cragg has over 29 years of experience in supervision, command, and ship-borne nuclear safety.

Michael T. Kirsch

NESC Principal Engineer

Mr. Michael T. Kirsch is a Principal Engineer with the 

NESC at Langley Research Center (LaRC). Mr. Kirsch 

joined the NESC from the NASA’s White Sands Test 

Facility (WSTF) where he served as the Deputy Manager responsible for planning and directing developmental and operational tests of spacecraft propulsion systems and related subsystems. Mr. 

Kirsch has over 18 years of experience in managing projects and test 

facilities.

NESC PRINCIPAL ENGINEERS

Dr. Michael G. Gilbert

NESC Chief Engineer

Dr. Michael G. Gilbert is the NESC Chief Engineer at 

Langley Research Center (LaRC). Before joining the 

NESC, he was Head of the LaRC Systems Management 

Office. Dr. Gilbert has over 30 years of engineering, 

research, and management experience with aircraft, missile, spacecraft, 

Space Shuttle, and International Space Station Programs.

Dennis B. Dillman

NESC Chief Engineer 

Mr. Dennis B. Dillman is the NESC Chief Engineer at 

NASA Headquarters. Mr. Dillman came to the NESC 

from the Goddard Space Flight Center (GSFC), where 

he chaired design reviews for major projects, including 

the Hubble Space Telescope Servicing Missions, the James Webb Space 

Telescope, and several Earth Observing System satellites. Prior to his time 

at GSFC, Mr. Dillman worked at the NASA Johnson Space Center managing Space Shuttle Orbiter sustaining engineering efforts and training 

Space Shuttle flight crews.

Derrick J. Cheston

NESC Chief Engineer

Mr. Derrick J. Cheston is the NESC Chief Engineer at 

Glenn Research Center (GRC). Mr. Cheston joined the 

NESC from his prior position at GRC as Chief of the 

Thermal/Fluids Systems Branch. Mr. Cheston has 23 

years of experience in aerospace engineering and management, including 

mechanical design and testing and thermal/fluids analysis.

NESC CHIEF ENGINEERS

Michael Hagopian

NESC Chief Engineer

Mr. Michael Hagopian is the NESC Chief Engineer 

at Goddard Space Flight Center (GSFC). Mr. Hagopian came to the NESC from his position as Associate 

Chief of the Mechanical Systems Division at GSFC. Mr. 

Hagopian has over 23 years of experience in the development of space and 

Earth science satellites.

Freddie Douglas, III

NESC Chief Engineer

Freddie Douglas, III is the NESC’s Chief Engineer at 

Stennis Space Center (SSC). Mr. Douglas joined the 

NESC from SSC where he served as the Deputy Manager of the Office of Safety and Mission Assurance. Mr. 

Douglas has over 24 years of management and technical 

experience. He has worked on several projects including the International 

Space Station, Hubble Space Telescope, post-Challenger Accident Return 

to Flight Effort and served as a neutral buoyancy diver.
48 NESC 2007 TECHNICAL UPDATE

BIOGRAPHIES

R. Lloyd Keith

NESC Chief Engineer

Mr. R. Lloyd Keith is the NESC’s Chief Engineer, as well 

as the Deputy Center Chief Engineer at the Jet Propulsion 

Laboratory (JPL). Mr. Keith has over 31 years of experience 

working in both technical and managerial positions. Mr. 

Keith has supported a number of flight projects including the Mars Pathfinder Project, SeaWinds, Stardust, Mars ’98, New Millennium Deep Space 

1, and the Flight Hardware Logistics Program.

Stephen A. Minute

NESC Chief Engineer

Mr. Stephen A. Minute is the NESC Chief Engineer at 

Kennedy Space Center (KSC). Mr. Minute came to the 

NESC from KSC, where he served as the Chief of the 

Space Shuttle Safety, Quality, and Mission Assurance Division. Mr. Minute has over 24 years of engineering and management experience in the Space Shuttle and International Space Station Programs.

Dr. Charles F. Schafer

NESC Chief Engineer

Dr. Charles F. Schafer is the NESC’s Chief Engineer at 

Marshall Space Flight Center (MSFC). Dr. Schafer came 

to the NESC from MSFC where he served as the Deputy 

Manager of the Propulsion Research Center of the Science 

and Technology Directorate. Dr. Schafer has over 42 years of experience in 

leading research and technology activities in advanced earth-to-orbit and inspace propulsion, including work in nuclear propulsion, plasma propulsion, 

advanced chemical propulsion, and new chemical propellant development.

Dr. James F. Stewart

NESC Chief Engineer

Dr. James F. Stewart is the NESC Chief Engineer at Dryden 

Flight Research Center (DFRC). Dr. Stewart joined the 

NESC from DFRC where he served as the Dryden Exploration Mission Director. Dr. Stewart has over 42 years of 

management and technical experience leading missile and aircraft programs.

David A. Hamilton

NESC Chief Engineer

Mr. David A. Hamilton is the NESC Chief Engineer at 

Johnson Space Center (JSC). Mr. Hamilton came to the 

NESC from JSC, where he served as Chief of the Shuttle/

Station Engineering Office and also as the Chairman of the 

Shuttle Chief Engineers Council. Mr. Hamilton has over 40 years of combined experience in NASA manned space flight programs, including Apollo, 

Skylab, Apollo-Soyuz, ISS, Space Shuttle, and Mir.

NESC CHIEF ENGINEERS Con’t.

Michael L. Aguilar

NASA Technical Fellow

Mr. Michael L. Aguilar is the NASA Technical Fellow for 

Software and is resident at Goddard Space Flight Center 

(GSFC). Mr. Aguilar joined the NESC from GSFC where 

he served as the James Webb Space Telescope (JWST) Instrument Software Manager. Mr. Aguilar has over 31 years of experience on 

embedded software development.

NASA TECHNICAL FELLOWS

Mitchell L. Davis

NASA Technical Fellow

Mr. Mitchell L. Davis is the NASA Technical Fellow for 

Avionics and is resident at the Goddard Space Flight Center 

(GSFC). Mr. Davis was the Chief Engineer of the Electrical 

Systems Branch at GSFC prior to joining the NESC. Mr. 

Davis has over 25 years of experience in power and avionics.

Cornelius J. Dennehy

NASA Technical Fellow

Mr. Cornelius (Neil) J. Dennehy is the NASA Technical 

Fellow for Guidance, Navigation and Control (GN&C) 

systems and is resident at Goddard Space Fight Center 

(GSFC). Mr. Dennehy came to the NESC from the Mission 

Engineering and Systems Analysis Division at GSFC, where he served as the 

Division’s Assistant Chief for Technology. Mr. Dennehy has over 27 years of 

experience in the architecture, design, development, integration, and operation of GN&C systems, and space platforms for communications, defense, 

remote sensing, and scientific mission applications.

George D. Hopson

NASA Technical Fellow

Mr. George D. Hopson is the NASA Technical Fellow for 

Propulsion and is resident at Marshall Space Flight Center 

(MSFC). Mr. Hopson came to the NESC from the Space 

Shuttle Main Engine Project Office, where he served as 

Director. Mr. Hopson has over 45 years of combined experience in Space 

Shuttle main engine, space propulsion, space systems dynamics, and project 

management.

Dr. Curtis E. Larsen

NASA Technical Fellow

Dr. Curtis E. Larsen is the NASA Technical Fellow for 

Loads and Dynamics and is resident at Johnson Space Center (JSC). Prior to joining the NESC, Dr. Larsen was the 

Technical Discipline Manager for Cargo Integration Structures in the Space Shuttle Program’s Flight Operations and Integration Office. Dr. Larsen has over 27 years of engineering experience with expertise in 

stochastic structural dynamics, structural safety, and probabilistic engineering applications.
NESC 2007 TECHNICAL UPDATE 49

BIOGRAPHIES

Dr. Robert S. Piascik

NASA Technical Fellow

Dr. Robert S. Piascik is the NASA Technical Fellow for Materials and is resident at Langley Research Center (LaRC). 

Dr. Piascik joined the NESC from the LaRC Mechanics 

of Materials Branch and the Metals and Thermal Structures 

Branch, where he served as a Senior Materials Scientist. Dr. Piascik has over 

23 years of experience in the commercial nuclear power industry and over 15 

years of experience in basic and applied materials research for several NASA 

programs.

Dr. Cynthia H. Null

NASA Technical Fellow

Dr. Cynthia H. Null is the NASA Technical Fellow for 

Human Factors and is resident at Ames Research Center 

(ARC). Before joining the NESC, Dr. Null was a scientist in 

the Human Factors Division and Deputy Program Manager 

of the Space Human Factors Engineering Project. Dr. Null has 21 years of 

experience lecturing on Human Factors, and another 16 years of experience 

in Human Factors applied to NASA programs.

Dr. William H. Prosser

NASA Technical Fellow

Dr. William Prosser is the NASA Technical Fellow for Nondestructive Evaluation and is resident at Langley Research 

Center (LaRC). Dr. Prosser joined the NESC from the Nondestructive Evaluation Sciences Branch at LaRC. Dr. Prosser 

has over 20 years of experience in the field of ultrasonic and acoustic emission 

sensing techniques.

Dr. Ivatury S. Raju

NASA Technical Fellow

Dr. Ivatury S. Raju is the NASA Technical Fellow for Structures and is resident at Langley Research Center (LaRC). Dr. 

Raju was the Senior Technologist in the LaRC Structures 

and Materials Competency prior to joining the NESC. Dr. 

Raju has over 32 years of experience in structures, structural mechanics, and 

structural integrity. 

Henry A. Rotter

NASA Technical Fellow

Mr. Henry (Hank) A. Rotter is the NASA Technical Fellow 

for Life Support/Active Thermal, and is resident at Johnson Space Center (JSC). Mr. Rotter joined the NESC from 

the JSC Crew and Thermal Systems Division and the Space 

Launch Initiative Program, where he was Engineering Manager and the Orbital Space Plane Team Leader for life support and active thermal control 

teams. Mr. Rotter has over 40 years of life support and active thermal control 

systems experience during the Apollo, Space Shuttle, and Orbital Space Plane 

Programs.

NESC TECHNICAL FELLOWS Con’t

Dr. David M. Schuster

NASA Technical Fellow

Dr. David M. Schuster is the NASA Technical Fellow for 

Aerosciences and is resident at Langley Research Center 

(LaRC). Prior to joining the NESC, Dr. Schuster was 

the Branch Head for the Structural and Thermal Systems 

Branch in the Systems Engineering Directorate. Dr. Schuster has over 29 years experience in the aerospace industry with expertise in 

aeroelasticity and integrated aerodynamic analysis
50 NESC 2007 TECHNICAL UPDATE

Ames

Research 

Center

Dryden Flight 

Research Center Wallops Flight

Facility Marshall Space 

Flight Center

Wallops Flight

Facility Langley Research

Center

Johnson Space 

Center

Stennis Space 

Center

Marshall Space 

Flight Center

Goddard Space Flight

Center

Kennedy Space 

Center

NASA Headquarters

Glenn Research

Center

Jet Propulsion

Laboratory

Frank H. Bauer

NESC Discipline Expert for Guidance Navigation and Control (2003-04

Currently serving as the Exploration 

Systems Mission Directorate Chief Engineer at NASA HQ

J. Larry Crawford

NESC Deputy Director for Safety (2003-

04) Left NESC to become Director of 

Safety and Mission Assurance at the 

Kennedy Space Center (KSC) and has 

since retired

Steven F. Cash

NESC Chief Engineer at MSFC (2005) 

Currently the Deputy Manager, Shuttle 

Propulsion Office at MSFC

Dr. Michael S. Freeman

NESC Chief Engineer at Ames Research 

Center (ARC) (2003-04) Retired

T. Randy Galloway

NESC Chief Engineer at Stennis Space 

Center (SSC) (2003-04) Currently the 

Director of the Engineering and Science 

Directorate at SSC

Dr. Edward R. Generazio

NESC Discipline Expert for Nondestructive Evaluation (2003-05) Currently 

a Senior Research Engineer, Research 

& Technology Directorate, LaRC

Dr. Richard J. Gilbrech

NESC Deputy Director (2003-05) Left 

the NESC to become the LaRC Deputy 

Center Director, in 2006 was named as 

the Stennis Space Center Director, and 

is currently the Associate Administrator 

for the Exploration Systems Mission 

Directorate

Dr. Charles E. Harris

NESC Principal Engineer (2003-06) 

Currently the Director, Research & 

Technology Directorate at LaRC

Dr. Steven A. Hawley

NESC Chief Astronaut (2003-04) Currently the Director of Astromaterials 

Research and Exploration Science at 

Johnson Space Center (JSC)

Marc S. Hollander

Manager, Management and Technical 

Support Office (2005-06) Currently Associate Director for Management, National Institutes of Health

Keith L. Hudkins

NASA Headquarters Office of the Chief 

Engineer Representative (2003-07)

Retired

Danny D. Johnston

NESC Chief Engineer at Marshall Space 

Flight Center (MSFC) (2003-04)

Left the NESC to work a detailed assignment at MSFC in the NASA Chief 

Engineer’s Office and has since retired

Michael W. Kehoe

NESC Chief Engineer at Dryden Flight 

Research Center (DFRC) (2003-05) 

Left the NESC to become the DFRC 

Liaison in the Crew Exploration Vehicle 

Flight Test Office at JSC and has since 

retired

Robert A. Kichak

NESC Discipline Expert for Power and 

Avionics (2003-07) Retired

Dr. Dean A. Kontinos

NESC Chief Engineer at Ames Research Center (ARC) (2006-07) Left the 

NESC to work a detailed assignment 

as the Technical Integration Manager of 

the Fundamental Aeronautics Program 

in the Aeronautics Research Mission 

Directorate at NASA HQ

Julie A. Kramer White

NESC Discipline Expert for Mechanical 

Analysis (2003-06) Currently the Chief 

Engineer, Crew Exploration Vehicle Office at JSC

Steven G. Labbe

NESC Discipline Expert for Flight Sciences (2003-06) Currently the Chief 

Engineer, Constellation Program Office 

at JSC

Matthew R. Landano

NESC Chief Engineer at NASA’s Jet 

Propulsion Laboratory (JPL) (2003-04) 

Returned to his assignment at JPL as 

the Director of Office of Safety and Mission Success

David S. Leckrone

NESC Chief Scientist (2003-06) Currently the Senior Project Scientist for 

the Hubble Space Telescope at GSFC

John P. McManamen

NASA Technical Fellow for Mechanical 

Systems (2003-07) Currently the Chief 

Engineer, Shuttle Program Office at 

JSC

Brian K. Muirhead

NESC Chief Engineer at NASA’s Jet 

Propulsion Laboratory (JPL) (2005-07)

Currently the Program Systems Engineer in the Constellation Program’s 

Program Systems Engineering Office 

at JSC

Dr. Paul M. Munafo

NESC Deputy Director (2003-04) Left 

the NESC to become the Assistant 

Director for Safety and Engineering at 

Marshall Space Flight Center (MSFC) 

and has since retired

Stan C. Newberry

Manager of NESC’s Management and 

Technical Support Office (2003-04) Left 

NESC to become the Deputy Center Director at Ames Research Center (ARC) 

and has since left NASA to accept a 

position at DoD

Dr. Shamim A. Rahman

NESC Chief Engineer at Stennis Space 

Center (2005-06) Currently the Propulsion Test Program Manager at SSC

Jerry L. Ross

NESC Chief Astronaut (2004-06)

Currently the Chief of the Vehicle Integration Test Office at JSC

Steven S. Scott

NESC Discipline Expert for Software 

(2003-05) Currently the Chief Engineer 

at GSFC

John E. Tinsley

NASA Headquarters Senior Safety and 

Mission Assurance Manager for NESC 

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NESC 2007 TECHNICAL UPDATE 51

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On July 16, 1969 at 9:32 a.m. EDT, the swing arms 

moved away and a plume of flame signaled the 

liftoff of the Apollo 11 Saturn V space vehicle and 

astronauts Neil A. Armstrong, Michael Collins and 

Edwin E. Aldrin, Jr. from Kennedy Space Center 
52 NESC 2007 TECHNICAL UPDATE

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American Institute of Aeronautics and Astronautics

Best Practices for Reliable and Robust Spacecraft Structures

I. S. Raju

1

, P. L. N. Murthy2, N. R. Patel

3

, P. J. Bonacuse

4

, K. B. Elliott

5

, S. A. Gordon6,

J. P. Gyekenyesi

7

, E. O. Daso8, P. Aggarwal

8

, and R. F. Tillman9

NASA Engineering and Safety Center

NASA Langley Research Center

Hampton, Virginia 23681

Abstract

A study was undertaken to capture the best practices for the development of reliable and

robust spacecraft structures for NASA’s next generation cargo and crewed launch

vehicles. In this study, the NASA heritage programs such as Mercury, Gemini, Apollo, and

the Space Shuttle program were examined. A series of lessons learned during the NASA

and DoD heritage programs are captured. The processes that “make the right structural

system” are examined along with the processes to “make the structural system right”. The

impact of technology advancements in materials and analysis and testing methods on

reliability and robustness of spacecraft structures is studied. The best practices and

lessons learned are extracted from these studies. Since the first human space flight, the

best practices for reliable and robust spacecraft structures appear to be well established,

understood, and articulated by each generation of designers and engineers. However,

these best practices apparently have not always been followed. When the best practices are

ignored or short cuts are taken, risks accumulate, and reliability suffers. Thus program

managers need to be vigilant of circumstances and situations that tend to violate best

practices. Adherence to the best practices may help develop spacecraft systems with high

reliability and robustness against certain anomalies and unforeseen events.

Introduction

NASA is currently in the process of developing the next generation crewed and cargo 

launch vehicles and spacecraft to return to the moon and beyond. With the experience

and knowledge base available from past similar programs, a document that captures

salient aspects of successful programs is being developed. This document serves as an 

important guide in evaluating next generation and future spacecraft concepts and 

proposals. As a part of this guide, guides for individual technical disciplines are being 

developed. Reliable and robust structural systems design is one of these technical

disciplines. The structures document describes pertinent issues, best practices, errors,

miss-steps, lessons learned, and summarizes the previously used design processes (tools

and standards) for the structures discipline.

 1 Langley Research Center, Hampton, Virginia, Fellow AIAA 2 Glenn Research Center, Cleveland, Ohio, Associate Fellow AIAA 3 The Aerospace Corporation, El Segundo, California, Senior Member AIAA 4 Army Research Laboratory at NASA Glenn Research Center, Cleveland, Ohio 5 Langley Research Center, Hampton, Virginia 6 Goddard Space Flight Center, Greenbelt, Maryland 7 Glenn Research Center, Cleveland, Ohio, Member AIAA 8 Marshall Space Fight Center, Huntsville, Alabama 9 Jet Propulsion Laboratory, Pasadena, California
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American Institute of Aeronautics and Astronautics

Structural systems provide the basic framework to distribute external and internal loads

resulting from all flight loads, ground loads, and associated operational and 

environmental loads. The primary objective of a structural system is to remain intact and 

experience minimal deformation when exposed to various environments, including

ground processing, testing, launch, on-orbit, and re-entry operations. Structural systems

also provide containment for pressures as in pressure vessels, pressure components, and 

pressurized structures. Structures tend to be a dependent subsystem in the sense that

many requirements flow to structures from other subsystems. Space systems are very 

complex products of multiple disciplines and therefore are multidisciplinary, and 

therefore require a multidisciplinary analysis and optimization approach to capture

various system interactions and sensitivities in order to obtain optimum system solutions,

develop flight constraints, and validate and verify the system architecture. As a result, as

illustrated in Figure 1, the development of the structural system is a complex iterative

design process.

This paper outlines the best practices that are essential to the design and production of

reliable and robust spacecraft structural systems. First, the NASA heritage programs are

examined. Lessons learned from these heritage programs are captured. Next the

processes that need to be used to “make the right structural system” are examined. Third,

the processes that need to be followed to “make the structural system right” are

addressed. In addition, a brief review of methods for assessing reliability and risk for

structural systems is provided. Finally, the lessons learned and the best practices are

presented.

Figure 1. Complex interactions involved in structural system design.
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Heritage Programs

Heritage programs such as Mercury, Gemini, Apollo, and the Space Shuttle program (see

Figure 2) are first examined [1-8]. A study of these programs resulted in several lessons

learned. They can be briefly summarized as follows:

• Design deficiencies result from the inability to predict load paths and load

distributions accurately. All load paths in a complex structure may be

difficult to discern. Thus careful analysis followed by a rigorous test program

should be conducted to uncover any design deficiencies.

• Testing of components requires care. Whenever possible, test hardware

should be structurally similar to flight hardware. Special attention needs to be

given to interfaces and boundaries to ensure that proper boundary conditions

are imposed on the system or component.

• Despite advances in analysis techniques, modeling and simulation verification 

and validation is a vital part of insuring the reliability of structural systems.

• A building block approach is required to design and build reliable complex 

structures. Key steps that need be followed are:

- Fully characterize special materials used in the structures and structural

components.

- Develop and validate, to the extent possible, accurate environmental

predictions and verify the techniques used in the predictions.

- Develop accurate structural dynamic and stress models and validate their

predictions. Avoid extrapolations of models and results.

- Develop a fracture control/nondestructive evaluation program.

- Develop extensive verification and validation procedures for:

! Modeling and analysis

! Coupon tests, subcomponent tests, component tests, full

scale tests, and flight tests

! Analysis and test correlation

- Develop rigorous manufacturing and quality control procedures.
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Figure 2. NASA Heritage Space Programs

Making the Right Structural System

Structural components (other than consumable or life limited items) are intended to have

sufficient durability to perform adequately over the expected service life of the system.

Structural systems deteriorate and/or develop damage due to a single cause or a

combination of causes such as: (a) the design is inadequate for the applied loading and 

environment (conceptual design or calculation error), (b) the loading (amplitude,

frequency, and/or interactions) is not well understood or underestimated, (c) the effects of

environment are underestimated (requirements specification error), (d) a flaw in the

materials or manufacturing is undetected (quality control and/or inspection error), and (e)

unexpected damage occurrs through unforeseen means (e.g. handling damage). Thus to 

make the right structural system, several best practices, such as the establishment and 

understanding of the proper design and mission requirements, the implementation of

trade studies, and the creation of sufficient verification and validation studies, need to be

instituted.

Design Requirements:

The primary purpose of a structure is to protect spacecraft systems and to ensure that the

system remains intact by maintaining the relative position of components under servicelife loads and environments. Thus the fundamental requirement of any space structure is
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to maintain structural integrity throughout the life of the structure. The process of

defining structural requirements for new spacecraft typically begins with a review of

previous development efforts and applicable technical standards. Both of these sources

should be mined for appropriate design constraints, testing requirements, methodologies,

and procedures. Care should be taken in selecting the requirements that will appear in the

final system specification. All requirements should add value, be clear in their intention,

and should not overly constrain the design and development. The list of requirements

should be determined through an active negotiation process between the project

management and the appropriate technical community. As a minimum, all NASA

programs should evaluate NASA and other government standards for applicability. In

general, these standards capture best practices, and they represent the starting point for

the design, analysis, and verification of structural systems within NASA and other

Government Agencies. If a program intends to deviate from the approach outlined in the

NASA standards, then it will most likely require that documentation of the technical

rationale or waiver be provided to the organizations performing technical oversight of the

program during the formal review process.

Mission Requirements:

Performance: Structural design, including the implementation of new technologies, is

driven by the system performance requirement goals. These performance requirements

are driven by the mission requirements. Demanding performance requirements combined 

with volume and weight constraints often lead to greater sensitivities to design 

uncertainties. Design uncertainties exist in material properties, environments, loads,

analyses, testing, and manufacturing. It is preferred to have a linear sensitivity of

performance to these parameters. On the other hand, a high performance design may 

require nonlinear dependence on these parameters. In that case, great care must be taken 

to characterize material properties, define environments, and validate analyses.

Manufacturing, quality control and assurance, and acceptance criteria must be enhanced 

to account for additional uncertainty. On the other hand, robust or conservative designs

can be used at a price of higher weight and possibly lower performance. The optimum

design choice probably lies between the two extremes. Trade and sensitivity studies must

be performed to determine the trade offs and select the optimum design.

Environments: The structural system is designed and tested to withstand all pertinent

environmental conditions, naturally occurring and induced, to which the system will be

subjected during its life-cycle. These life-cycle environments should be identified as

early as possible in the structural design process, and appropriate loading conditions

should be defined as requirements for design and testing. Typical environments include

production, testing, integration, storage, transportation, launch, ascent, thermal, radiation,

meteoroid impact, vacuum, dust or contamination, re-entry, and landing. Care should be

taken to consider load uncertainties, combine environmental effects, and contingency 

load cases. The structural system should also be designed to withstand the cumulative

effects of the environments without loss of mission performance.
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Trade Studies:

The preliminary requirements for the design of a structural system typically involve the

definition of mass allowables, volume constraints, and the specification of both static and

dynamic design loads. These requirements stipulate the trade space for evaluating 

different structural concepts. In addition, manufacturability, inspectability, and cost (both

initial and lifetime) may be additional constraints on the trade space. In most cases, the

structural design trades are aimed at minimizing vehicle weight while showing positive

margins under the specified design loads and providing sufficient stiffness to meet

mission goals. One of the first trades in developing a preliminary structural design is to

define the load paths and the type of structure that will sustain the design loads. Trade

studies can also be performed to evaluate different material types (for example,

composite vs. metal), the implementation of new technologies, and different construction 

methods.

Verification and Validation (V/V): Verification and validation are terms often used in 

relation to the qualification of reliable structures. The terms verification and validation 

are often misused or used interchangeably. NASA system engineers define verification

as “proof of compliance with specification as determined through a combination of test,

analysis, and demonstration” [9]. Validation is defined as “proof that a product

accomplishes the intended purpose as determined through a combination of test, analysis,

and demonstration” [9]. In other words; verification is demonstrating that the product

meets the design requirements, and validation is demonstrating that the product meets the

goals of the intended application. These definitions originate at the system level and 

primarily apply to hardware products. A second set of definitions are commonly used in

reference to computational models. Model verification, as defined by AIAA, ASME, and 

DoD [10-12], is “the process of determining that a computational model accurately 

represents the underlying mathematical model and its solution.” Model validation is “the

process of determining the degree to which a model is an accurate representation of the

real world from the perspective of the intended uses of the model.” In this case,

verification is ensuring the computational model is correct in terms of the governing 

equations (stress, strain, motion); validation is ensuring the modeling effort captures the

physics of the intended application. Producing reliable structures requires meeting both

sets of definitions. For example, computational models need to endure sufficient V/V to

define or reduce uncertainty and demonstrate sufficient accuracy to support program

decisions. This is particularly important when computational models are to be used for

product V/V. Best practice dictates that all structural systems should undergo a rigorous

V/V process.

The following are examples of lessons learned taken from various past aerospace

programs that relate to “making the right structural system”:

• Document engineering requirements as clearly as possible. All requirements,

including seemingly minor changes, should be clearly documented and 

tracked in order to avoid misinterpretation.

• In a totally new system, requirements may have to be continually reviewed for

applicability. Requirements may change as a result of trade studies or design 

maturity.
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• Each requirement should be traceable to a compliance matrix. All test data

should be inspected for trends and “out of family” values, even when all

values are within the expected range. Anomalous data should be thoroughly

investigated.

• Impact of requirements changes for a subsystem should be properly evaluated 

on the system and interfacing subsystems.

• Review out-of-flow processes to ensure no steps are bypassed.

• Spacecraft must be designed to withstand worst-case life-cycle environments.

All possible load combinations should be considered. Credible mission 

failure scenarios should be considered in evaluating the failure modes of the

structure.

Making the Structural System Right

The key aspects for reliable and robust structures are design, analysis, manufacturing and 

process control, testing, and quality assurance. Each topic must be properly addressed to 

“make the structural system right”.

Design:

Primary and secondary structures of space systems are designed to provide sufficient

strength, rigidity, and other characteristics required to sustain the critical loading 

conditions without damage or degradation of performance throughout their service life.

Several key design aspects necessary to ensure a reliable structure are structural integrity 

requirements, fatigue and fracture control, factors of safety, material properties, and

tolerance requirements.

Analysis:

Structural analyses are performed to predict structural response to the critical loads and 

environments anticipated during the service life of the structure. Typical analyses

include investigations of fatigue, safe-life, and fail-safe considerations. These analyses

are important to establish the service life, tolerance of the structure to defects, design 

margins, and residual strength. To ensure a reliable structure, it is important to verify the

analysis models and validate the analysis predictions over the range of use.

Manufacturing and Process Control:

The design of reliable and robust structures requires well-characterized fabrication 

processes and procedures. The fabrication process for each structural item is a

controlled, documented process. Proven processes and procedures for fabrication and 

repair are needed to preclude damage or material degradation during material processing 

and manufacturing operations. An inspection plan is required to identify all key process

parameters essential for design verification. In-process inspection or process monitoring

are needed to verify setup and acceptability of critical parameters during the

manufacturing process.
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Testing:

Demonstrations are required to ensure that a structural system meet both mission and 

regulatory requirements. These demonstrations can be performed in four ways: 1) by 

heritage/similarity, 2) by analysis, 3) by qualification testing, and 4) by a combination of

1, 2, and 3. Qualification through heritage/similarity is not a reliable process without

adequate analyses and tests to conclusively demonstrate similarity in materials, loads,

environments, and responses. Qualification through analysis may be used when testing 

cannot demonstrate a target environment, such as zero-g or combined load effects, or the

tests required are hazardous or unrealistic in terms of cost and schedule. By far the best

approach to qualification is through testing. The mantra for a qualification-testing 

program should be “Test what you fly, and fly what you test.”

Quality Assurance:

A quality assurance program based on a comprehensive study of the product and

engineering requirements is established to ensure that necessary nondestructive

inspection and acceptance proof tests are performed effectively. The program ensures

that no damage or degradation occurred during material processing, fabrication,

inspection, acceptance tests, shipping, storage, assembly, and operational use and 

refurbishment, and that defects that could cause failure are detected or evaluated and 

corrected. Acceptance proof tests are conducted on pressure vessels, pressurized 

structures, and composite structures for verification of workmanship.

Reliability Assessment Methods

Risk and reliability are complementary terms. Reliability is a quantified probabilistic

assurance that a system or a product/device (or structure) will perform satisfactorily (i.e.

will not fail, and will satisfy performance requirements) during its intended lifetime

under specified operating conditions. Probability of failure refers to likelihood that the

system will fail to satisfy the designated performance requirement. Risk, on the other

hand, combines the probability of failure and the consequence of failure. Risk is

generally defined as a product of the probability of failure and the cost (consequence) of

failure.

A distinction also needs to be made between probability and statistics. Statistics is the

mathematical quantification of uncertainty (mean, standard deviation, and other higher

moments) mainly through the analysis of measured data. Probability theory uses

statistical data to quantify the likelihood of occurrence of specific events.

Many structural systems (particularly space propulsion structures) are one-of-a-kind and 

hence have little or no learning curve. Generally, space propulsion systems are relatively 

large and expensive; and often they are not fully tested prior to their use nor are they 

tested repeatedly to create a statistical database. These propulsion systems may also have

relatively long exposure periods and are designed for low risk. Often there is little or no

redundancy is in these systems because of cost and weight considerations. These factors

make the reliability analysis of these systems extremely challenging.
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Margins and Factors of Safety:

Engineers have always recognized the existence and presence of uncertainty in the

analysis and design of structural systems. These uncertainties can arise due to human

factors (error in analysis and/or fabrication), limitations in technology, inherent

randomness in the material properties, the environment in which the system operates, and 

the specific utilization of the structural system. Traditionally, uncertainty has been 

accounted for by using safety factors and/or knock-down factors. Structural reliability

and robustness is improved by increasing the safety margins for critical structures (with a

cost and weight penalty) and by practicing rigorous quality assurance (QA) and quality

control (QC) techniques.

Depending upon the nature of their criticality, space system structures and structural

components are designed using either a fail-safe or a safe-life design philosophy. Failsafe systems, sometimes referred to as fool-proof systems, are designed such that their

failure does not affect other components and systems. In the safe-life design philosophy,

systems are designed to survive a specific design life with a chosen reserve.

Historically, the use of empirical safety factors has been the prevalent method of making

designs more reliable. However, deterministic safety factors do not provide a

quantitative measure of risk. In contrast, probabilistic analysis methods can provide this

information.

Traditionally, safety factors are estimated based on rules-of-thumb and experience and 

are intended to be conservative. Selection of safety factors is insensitive to required 

reliability. It is possible to establish relationships between the traditional safety factors

and the more rigorous probabilistic methods provided the underlining distributions and

the statistical parameters for various design factors are known. Lately, there has been a

push to relate safety factors to probabilistic or statistical methods. Safety factors that are

based on standard probabilistic analyses provide a transparent approach to the end user

recognizing the statistical nature of material properties and stress, the applicability of the

failure theory, fidelity of the analysis techniques, and the required reliability. In applying 

this methodology, all design parameters of interest are typically assumed to have normal

distributions [13]. This is an approximation, but in the absence of adequate data, the

normal distribution assumption is advantageous in that it can be fully characterized by 

just two parameters: the mean and the variance. Since the applied stress and allowable

strength are statistical in nature and assumed to be normal (with known parameters), the

safety factor can be shown to be a function of probability of failure, mean and standard 

deviation of strength, and mean value and standard deviation of applied stress.

Probabilistic Approaches:

Usually, in risk-based design methodologies, a traditional load and resistance model is

used. In its most fundamental form, design safety is ensured by requiring that the

resistance is greater than the load. The safety factor is defined as the resistance divided 

by load. The determination of resistance and load distributions depend on the specific

application. In aerospace applications, another measure of safety, margin of safety 
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(MOS), is often used. Positive values of MOS indicate safe designs, and negative values

indicate unsafe designs.

In a probabilistic analysis, the design safety is ensured by requiring that the overlap 

between the load and resistance (strength) probability distribution curves be minimized 

within the constraints of economy. Figure 3 illustrates and compares the traditional and 

probabilistic design methodologies. The probability of failure is defined as the total area

of the overlap [14]. The shapes of the curves are represented by probability density 

functions. In certain situations, the resistance distribution curve needs to account for

more than the traditional strengths. For example, when the structural components are

subjected to variable amplitude, high frequency loading where fatigue is the primary 

failure mechanism, the resistance needs to properly account for history dependent fatigue

damage accumulation.

Figure 3. A comparison of traditional vs. probabilistic design methodologies

Generally, the methods to quantify the element level reliability (component reliability)

can be broadly grouped into four categories as, (1) first-order reliability methods

(FORM) and second-order reliability methods (SORM), (2) Monte Carlo simulation and 

its derivatives like efficient sampling methods etc., (3) response surface approaches, and 

(4) sensitivity-based probabilistic finite element analysis. References 14-17 provide

details on these methods.

Load Resistance

Calculated

Factor of safety

Calculated

Knockdown factor

Margin

Traditional Factor Of Safety Approach

Load

Resistance

(strength)

Load or resistance

Probability

density

Failure

(overlap region) 

Probabilistic Approach
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The state-of-the-art in the area of structural reliability assessment has improved 

significantly in the past two decades both in component and system level reliability

estimation. Many commercial finite element codes have adopted probabilistic analyses

methods [18,19]. These methods have been applied successfully in the areas of material

uncertainty characterization, probabilistic fracture mechanics, probabilistic fatigue

analysis, and probabilistic analysis of structural systems. However, these methods are

computationally intensive. The challenge that remains is to synthesize, adapt, and

simplify research efforts into practical and efficient methods that can be used for a variety

of engineering applications.

Best Practices Based on Lessons Learned

The following are examples of the best practices developed based on the lessons learned 

taken from various past aerospace programs. Adherence to these practices will help

ensure the development of reliable and robust structural systems.

Qualification

• Thoroughly evaluate heritage systems and data (test and analysis) as well as

the applicability of using “existing” or “flight proven” equipment.

• Unexpected hardware behavior in test and/or flight is often a sign of

impending failure and must be thoroughly investigated. Perform thorough

post-flight analyses.

• Replacement materials should be sufficiently tested under conditions that

realistically simulate flight conditions, and the results should be correlated 

with those exhibited by the original material systems.

• Study past anomalies that involved similar designs or technologies and

implement appropriate corrective actions.

• Safeguard flight hardware against inadvertent damage due to handling and 

over-testing.

• Do not succumb to launch schedule pressure and compromise engineering 

recommendations.

Analysis and Testing

• All design changes must be thoroughly analyzed and tested.

• Analysis should properly account for all flight environments.

• Inaccuracies in material properties, structural loads, and environments continue to

threaten mission success. Validation of material properties, structural loads, and

environments through rigorous test campaigns is the best method of insuring 

reliable structures.

• Test failures must be thoroughly investigated and the root causes of the test

anomalies ascertained and understood.

• Verify field installation of all single point failure items.
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Design, Manufacturing, and Assembly

• Thoroughly verify the interfaces of all subcontracted items.

• Honeycomb structures should be vented wherever possible. If un-vented design 

cannot be avoided, sufficient testing including development, qualification, and

proof tests should be conducted under applicable temperature and vacuum

conditions.

• Changes and some non-conformances typically do not go through material review

board processes. All changes and discrepancies should be properly evaluated.

• 11th-hour modifications at the launch site require thorough evaluations.

• Protect the flight hardware from handling and transportation damage. Provide

ample checks for damage detection.

• Design hardware to minimize the areas that cannot be inspected, and avoid the use

of potential contaminants whenever possible. Account for all loose materials used 

during assembly.

Concluding Remarks

Spacecraft structural systems are complex and have multiple interacting components. As

such these structural systems can only be developed through complex iterative design 

process. Various best practices that lead to the development of reliable and robust

spacecraft structures are reviewed.

NASA heritage programs such as Gemini, Mercury, Apollo, and the Space Shuttle are

examined. Lessons learned from these programs are captured. To be able to build an 

appropriate structural system for a mission, design and mission requirements and the

environment must be adequately defined. Then, trade studies and verification and 

validation need be performed. To build the structural system that performs as intended 

needs design, analysis, manufacturing and process control, testing, and quality assurance.

Since the first human space flight, the best practices for reliable and robust spacecraft

structures appear to be well established, understood, and articulated by each generation of

designers and engineers. However, the implementation of these best practices appears to 

be a problem. When the best practices are ignored or short cuts are taken, reliability 

suffers and risks accumulate. Program managers deviate from best practices due to the

programmatic and resource (cost and schedule) issues brought on by anomalies and 

unpredicted problems, and unforeseen events. Thus for a reliable structural system,

program managers need to be vigilant when anomalies and unforeseen problems arise

that tend to violate best practices.
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References

 1 Douglas, W. H., McIntosh, G. P., and Menegar, L. S., “Spacecraft reliability and qualification,” Chapter

10, Gemini Midprogram Conference, NASA-SP 121, 1966, pp.89-99.

 2 Dineen, R. C., “Development of the Gemini Launch Vehicle,” Chapter 16, Gemini Midprogram

Conference, NASA-SP121, 1966, pp. 147-149.

 3 Mitchell, W. B., Maynard, O. E., and Arabian, D. D., ”Gemini results as related to the Apollo program,” 

Chapter 22, Gemini Summary Conference , NASA-SP 138, 1967, pp. 329-336.

 4 Smith, P. D.,“Apollo experience report: Spacecraft structure subsystem,” NASA Technical Note TN

D-7780, 1974.

 5 Ryan, R. S.,“A history of aerospace problems and their lessons,” NASA Technical Paper

TP-3653, 1996

 6 Glynn, P. C. and Moser, T. L.,“Orbiter structural design and verification,” in Space Shuttle Technical 

Conference, N. Chaffee (Compiler), NASA Conference Publication 2342, Part 1, pp, 345-356, 1983.

 7 Coldwater, H. G., Foll, R. R., Howell, G. J., and Dutton, O. J., “ Space shuttle external tank performance 

improvements – The challenge,” in Space Shuttle Technical Conference, N. Chaffee (Compiler),

NASA Conference Publication 2342, Part 1, pp, 357-364, 1983.

 8 Ryan, R. S., “Practices in adequate design,” NASA Technical Paper TP-2893, 1989.

 9 NASA NPR 7120.5C, “NASA Program and Project Management Processes and Requirements”. 2006.

10 AIAA G-077-1998, Guide for the Verification and Validation of Computational Fluid Dynamics

Simulations, 1998.

11 Verification & Validation in Computational Solid Mechanics, ASME V&V 10-2006, ASME, NY, NY.

12 DoD Instruction 5000.61, DoD Modeling and Simulation (M&S) Verification, Validation, and

Accreditation (VV&A), 2006.

13 Ullman, D., “Less fudging on fudge factors,” Machine Design, pp. 107-111, October 1986.

14 Haldar, A. and Mahadevan, S. Probability, Reliability and Statistical Methods in Engineering Design. 

Wiley and Sons, New York, 2000.

15 Nowak, A.S. and Collins, K.R. Reliability of Structures. McGraw Hill, Boston, 2000.

16 Wu, Y. -T., Burnside, O. H. and Cruse, T. A. ”Probabilistic methods for structural response analysis,” in

 W.K. Liu and T. Belytschko (Editors), Computational Mechanics of Probabilistic and Reliability

Analysis. Elmpress, Switzerland, pp. 182-195, 1987.

17 Cruse, T. A., Burnside, O. H., Wu, Y. -T., Polch, E. Z. and Dias, J. B. “Probabilistic structural analysis 

methods for select space propulsion system structural components (PSAM),” Computers and Structures, 

Vol. 29 (5), pp. 891-901, 1988.

18 ANSYS General Purpose Finite Element Code, ANSYS Inc., Cannonsburg, PA, 2006.

19 MSC-NASTRAN Finite Element Program, MSC Software Corporation, Santa Ana, CA, 2006.

20 NASA Safety Manual, NPG 8715.3, Jan. 24, 2000.

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NESC 2007 TECHNICAL UPDATE 65

RECENT NESC PUBLICATIONS

1. NASA/TM-2006-214517 Technical Assessment of the Space Shuttle Program 

(SSP) Thermal Protection System (TPS) Cure 

In Place Ablative Cure In Place Ablative Applicator (CIPAA) Utilizing Shuttle Tile Repair 

(STA)-54 for On-Orbit Tile Repair. NESC REPORT RP-06-76/05-007-E

2. NASA/TM-2006-214535 NASA Engineering and Safety Center’s Super Problem Resolution Human Factors Team Report - Design, 

Development, Testing, and Evaluation: Human Factors Engineering. NESC REPORT RP06-108/05-173-E 

3. NASA/TM-2007-214873 External Tank 

(ET) Alternative Liquid Hydrogen (LH2) Ice/

Frost Ramp (IFR) Design Concept Assessment. NESC REPORT RP-06-96/06-014-E 

4. NASA/TM-2007-215080 Evaluation of 

Land v. Water Landings for CEV. NESC REPORT RP-07-29/06-020-E

5. NASA/TM-2007-215084 Independent 

Review Support for Phoenix Mission Robotic 

Arm Brush Motor Failure. NESC REPORT RP07-13/06-050-E

6. NASA/TM-2007-215085 Dawn High Voltage Electronics Assembly Failure Support. 

NESC REPORT RP-07-51/07-011-E

7. NASA/TM-2007-215091 Dawn Waveguide Venting Analysis Review. NESC REPORT 

RP-07-49/07-022-E

8. NASA/TM-2008-215101 Crew Launch 

Vehicle (CLV) Project Reaction Control System 

(RCS) Thrust and Propellant Weight Sizing. 

NESC REPORT RP-07-35/06-021-E

9. NASA/TM-2008-215100 ISS S-Band Corona Discharge Anomaly. NESC REPORT RP06-115/06-028-E

10. NASA/TM-2008-215099 ET Bipod Bolt 

Locking Feature Verification. NESC REPORT 

RP-06-53/06-032-E

11. NASA/TM-2008-215102 External Tank 

(ET) Foam Thermal/Structural Analysis Project. 

NESC REPORT RP-06-55/06-012-I

12. NASA/TM-2008-215098/06-034-E CEV 

LAS Aero Evaluation. NESC REPORT RP-06-

85

13. NASA/TM-2008-215104 Feasibility of 

Conducting J-2X Engine Testing at the GRC 

Plum Brook Station B-2 Facility. NESC REPORT RP-07-20/06-049-E

14. ICCES ‘07 - 14th International Conference 

on Computational & Experimental Engineering and Sciences - Composite Overwrapped 

Pressure Vessel Issues for Spacecraft.

15. 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials 

Conference - Best Practices for Reliable and 

Robust Spacecraft Structures.

16. 18th Engineering Mechanics Division 

Conference of the American Society of Civil 

Engineers - Probabilistic Modeling of Space 

Shuttle Debris Impact.

17. 29th International Thermal Conductivity Conference (ITCC) and 17th International 

Thermal Expansion Symposium (ITES) - A 

Return to Innovative Engineering Design, 

Critical Thinking and Systems Engineering.

18. AIAA Guidance, Navigation, and Control 

Conference & Exhibit - GN&C Engineering 

Best Practices for Human-Rated Spacecraft 

Systems. 

19. Indian Society for Advancement of Materials and Process Engineering Aerospace 

Structures - Challenges and Future Directions.

20. Computer Modeling in Engineering & 

Sciences Journal - Structural Analysis of the 

Right Rear Lug of American Airlines Flight 

587 - Computer Modeling in Engineering & 

Sciences.

22. Space Transportation System (STS)-114 

External Tank (ET)-121 In-Flight Anomaly 

(IFA) Investigation.

23. Rudder Speed Brake Power Drive Unit 

Motor Dry Film Lubrication Bolt Issue. NESC 

Report RP-08-04

24. Peer Review#3 of the Government Furnished CEV Aerodynamics/Aerothermodynamic, Database/Models & Methodologies. 

NESC Report RP-07-101

25. Space Shuttle External Tank (ET) Ice Mitigation. NESC Report RP-07-100

26. Crawler Transporter New Shoe Failure. 

NESC Report RP-07-98

27. Critical Flaw Size Analysis for Ares IX Upper Stage Simulator Element Design. 

NESC Report RP-07-86

28. Crawler Transporter New Shoe Failure. 

NESC Report RP-07-80

29. Review of Analytical Tools for Assessment 

of Orbiter Tile Damage Effects on Vehicle 

Thermal and Structural Response Revised. 

NESC Report RP-07-79

30. NDE for ET TPS Closeout Verification Volume II. NESC Report RP-07-75

31. BOK3 computer Evaluation Report. NESC 

Report RP-07-70

32. SSPTS PTU/APCU OV-105 Installation 

Risk Assessment Final Report. NESC Report 

RP-07-68

33. NASA Standard Initiator (NSI) Independent Review for Phoenix Project. NESC Report RP-07-60

34. Reliability and Redundancy Trades. NESC 

Report RP-06-108

35. Integrated Composite Overwrap Pressure 

Vessel (COPV) Technical Issues Summary. 

NESC Report RP-07-48

36. STS-117 Hail Repair Assessment. NESC 

Report RP-07-47

37. Shuttle Kevlar Composite Overwrapped 

Pressure Vessel Safety for Flight Concern. 

NESC Report RP-07-34

38. Composite Crew Module Pressure Vessel. 

NESC Report RP-07-28

39. Support STS-114 Gap Filler Anomalies 

Tiger Team Investigation. NESC Report RP07-12

40. GSE T-0 Umbilical to SSP Flight Element 

Assessment. NESC Report RP-07-01

41. DART Mishap Investigation Board. NESC 

Report RP-06-119

42. Crew Launch Vehicle (CLV) First Stage 

Thrust Vector Control (TVC) Propellant Options. NESC Report RP-06-113

43. Design Development Test & Evaluation 

(DDT&E) Considerations for Robust and Reliable Human Rated Systems. NESC Report 

RP-06-108

44. International Space Station Fiber Optic 

Workmanship. NESC Report RP-06-61
National Aeronautics and Space Administration

Langley Research Center

Hampton, VA 23681

www.nasa.gov

NP-2008-01-59-LaRC