2011 TECHN ICAL U PDATE

NASA ENGINEERING & SAFETY CENTER

NESC

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Newsletter 
2011 NESC TECHNICAL UPDATE

Welcome to the 2011 NASA Engineering and

Safety Center (NESC) Technical Update

This past year has been a time of transition—marking the retirement of the 

Space Shuttle Program and the beginning of commercial crew partnerships 

and the new programs that will take NASA beyond Low Earth Orbit. The Agency 

continued to support the operation of the International Space Station and the 

development of numerous science spacecraft and aeronautic advancements. 

Along the way, the NESC has continued to provide independent test and 

analysis for critical areas across the Agency—whether it is in architecting a 

path for human exploration, selecting materials to be used in the next generation 

of spacecraft, or anomaly resolution for orbiting satellites. By providing a place 

for the Agency’s engineering, science, and safety communities to turn to for 

independent technical expertise, the NESC is fulfilling our purpose of ensuring 

mission success through engineering excellence. 

In addition to highlighting the many contributions from the NESC’s activities, 

we have featured some of the innovative techniques that have resulted from 

our assessments. Through the NESC’s leadership, investments made in solving 

project-specific issues have been leveraged to provide lasting benefits to other 

current and future endeavors. Sharing the results and lessons learned from 

our activities is an important role for our organization.

The strength of the NESC model is the matrix support from the Centers, 

along with expertise from industry and academia. The NESC’s success is 

made possible through the time and talent of these individuals, along with the 

support and cooperation of their home organizations. This year we are pleased 

to highlight just a few of the contributors to the NESC’s multidisciplinary, 

multigenerational teams as part of the Center Focus section.

Through the dedicated efforts of our extended team of experts, the NESC 

remains committed to being a value-added resource for the Agency. We will 

continue to evolve and adapt to provide timely and relevant data and information 

for Agency decision makers. The NESC is pleased to provide this Technical 

Update for 2011. 

1
NESC Director Mr. Ralph Roe Jr., left, and NASA Chief Engineer,

Dr. Michael Ryschkewitsch.

NESC Overview

NASA\George Homich

The NASA Engineering and Safety Center (NESC) 

employs the talents and diversity of NASA’s workforce to 

ensure safety and mission success for NASA’s high-risk 

programs. Within the framework of the NESC, hundreds 

of scientists and engineers from all 10 NASA Centers 

contribute to NESC activities each year. 

The NESC is a part of NASA’s Office of the Chief 

Engineer and is also closely affiliated with the Office

of Safety and Mission Assurance. This arrangement

allows independence, objectivity, and flexibility when 

working with other NASA organizations. The primary 

mission of the NESC is to ensure safety through engineering excellence by assembling technical expertise

from across the country into focused teams, called 

assessment teams, to quickly address specific technical 

issues. The NESC has supported programs and projects 

throughout NASA and other federal agencies such as 

assisting with the Trapped Chilean Miner Rescue Operation and the National Highway Traffic Safety Administration Toyota Unintended Acceleration Investigation.

The NESC core team members are full-time NESC 

employees and form the nucleus of each assessment 

team. The core team provides the leadership, human 

and facility resource allocation, managerial support, 

and technical and cross-Center integration for each 

assessment. The NESC extended team is made up of the 

Technical Discipline Teams (TDTs), which represent a pool 

of engineering and technical talent. There are 18 TDTs, 

each one focusing on an engineering discipline, and most 

are led by a NASA Technical Fellow. The Technical Fellows 

are members of the NESC core team, while the TDTs are 

populated with engineers and scientists chosen for their 

technical knowledge and experience and drawn from 

NASA Centers, academia, industry, or other government 

The NESC Model

Cover: Left, shell buckling test 

preparation–page 29. Right, water 

impact testing of a boilerplate Orion 

crew module–pages 13,36,37.

2

Contents

NESC Overview ......................... 2-7

Technical Highlights .................. 8-32

Exploration .......................... 8-13

Space Operations ................... 14-20

Science ................................. 21-26

General .................................. 27-32

Innovative Techniques ............... 33-39

Center Focus ............................. 40-53

Awards & Recognition ............... 54-56

Biographies .............................. 58-61

NESC Alumni ............................ 62

Publications ............................. 63-64
2011 NESC TECHNICAL UPDATE

NESC Overview

agencies. When the assessment lead determines the 

requirements for the assessment, he or she will draw 

the appropriate personnel from the TDTs through the 

Technical Fellows.

One precept of the NESC is to provide justification and 

proof using data and documentation for decisions

made by the NESC. All assessments conclude with a

final report, which contains test results, analyses, 

findings, observations, recommendations, and lessons 

learned. Each report must be reviewed and approved by

another unique element of the NESC: the NESC Review 

Board (NRB). 

The NRB succeeds by using the principle that viewing 

an issue from different vantage points results in a more 

complete understanding. With this in mind, the members 

of the NRB come from all the offices of the NESC (core 

team) and represent all 10 NASA Centers and each of the 

TDT disciplines. Their diverse viewpoints and experiences 

result in a robust decision-making process in the NRB. 

Engineers that participate in the NESC assessments 

gain a broader NASA-wide perspective, problem-solving 

experience, useful technical contacts, and are able to take 

this experience with them when they return to their home 

Centers. In fact, many of the core team members are not 

permanent and eventually return to their home Centers 

to apply lessons learned within their organizations. 

The NESC is also striving to ensure a productive and 

technically prepared workforce for NASA’s future by 

integrating junior engineers into the NESC assessments. 

This concept began with the Resident Engineer Program, 

where early-career NASA employees were invited to join 

the NESC for 1-year detail assignments. This has evolved 

into a broader-reaching effort where junior engineers will 

be chosen to support individual assessments on a caseby-case basis, thus allowing more people the opportunity 

to work with the NESC and learn from the NESC members.

As NASA continues to push the boundaries of technology 

and exploration, the NESC contributes by providing a 

model that taps into the talented NASA workforce and 

capitalizes on the strength found in its diversity. This is as 

crucial for new projects and initiatives as it has been with 

mature operational programs like the Space Shuttle and 

the International Space Station. 

For more information or to submit a technical request, 

contact the NESC online at nesc.nasa.gov.

The NESC Assessment Team Structure

Approximately 700 Members

NESC Extended Team

18 Technical

Discipline Teams

• Aerosciences • Avionics

 • Electrical Power 

• Flight Mechanics

• Guidance, Navigation,

and Control • Human Factors

• Human Spaceflight Operations

 • Life Support/Active Thermal

• Loads and Dynamics

• Materials

• Mechanical Systems

• Nondestructive Evaluation

• Passive Thermal • Propulsion

• Robotics • Software

• Structures

• Systems Engineering

Member

Percentage • NESC Principal Engineers

Assessment Team Leads

• NESC Chief Engineers

NESC Points of Contact

at each Center

• Management and Technical

Support Office

Contracts, Budgets,

Partnerships

• NASA Technical Fellows

Senior Technical Experts/TDT

Leadership

• Systems Engineering Office

Technical Integration

NESC Core Team

Approximately 60 Members

Assessment

Team

NASA

Engineers 

71%

Industry

22%

Academia

5%

Other

Government

Agencies

2%

The NESC Organization

3
2011 NESC TECHNICAL UPDATE

NESC Overview

NRB approves 

final report

Outbrief to 

Stakeholders

Conversion to 

NASA Technical 

Memorandum

General

Distribution

Technical 

Bulletins

Lessons

Learned

NRB

NRB

NRB

NESC Chief Engineers

Make request

NASA Other federal agencies

Principal 

Engineer lead

Approve plan

Systems Engineering Office 

NESC

Core Team Extended Team

Assessment Team

Accept request

Principal 

Engineer lead

NESC

Core Team Extended Team

Assessment Team

2

3

1

Write final report

Formulate findings, observations, 

and recommendations

Form and lead 

Assessment Team

Develop assessment plan

Process request 

Conduct initial evaluation

Perform testing, modeling, 

analysis, and data collection

Systems Engineering Office responds to all 

new requests where they are screened and 

assigned to one of the NESC Chief Engineers 

(NCE) for an initial evaluation. The NESC 

Review Board (NRB) then decides whether to 

proceed with the assessment.

A lead is assigned, usually from the Principal 

Engineers Office, to run the assessment. The 

team then develops the assessment plan, 

which goes back to the NRB for comments 

and approval.

The team proceeds with the technical portion 

of the assessment. This may entail testing, 

data analysis, literature searches, interviews, 

modeling—whatever has been specified in the 

plan and is necessary to meet the goals of the 

assessment. As the assessment draws to a 

close, the team formulates findings, observations, and recommendations drawn from the 

data and publishes them in a final report, which 

is sent to the NRB for approval or suggested 

modification.

The Process for Finding Solutions to Difficult Technical Problems 

Assessments form the structure and define the process the NESC uses to respond to requests and arrive at 

solutions to technical issues. The length of time an assessment takes, as well as the size of the assessment 

team, are highly variable. The process outlined below can be tailored to accommodate a given assessment.

4
2011 NESC TECHNICAL UPDATE

NESC Overview

NESC Operational Statistics

Accepted Requests by Mission Directorate: 427 Total

All statistics as of September 30, 2011

No assessments Aeronautics Exploration Space Operations General Science

Yearly totals

4

48 45 48 67 54 58 59 48

Safety &

Mission

Assurance

at Centers

4%

Program

Management 16%

NESC 

23%

Engineering & Scientific 

Organization 43%

Source of Accepted Requests: 427 Total

Anonymous 1% 

Other NASA Offices 1%

Office of Chief

Engineer 3%

Center

Management 2%

Office of Safety and

Mission Assurance 3%

External

to Agency

4%

ARC

24

74

171

13

GRC

51

MSFC

133

10

DFRC GSFC JPL JSC LaRC SSC

57

KSC

52

93

Employees Supporting NESC Assessments

Totals by 

Fiscal Year

5
2011 NESC TECHNICAL UPDATE

NESC Overview

Over the past year, the 15 NASA Technical 

Fellows continued to serve as the senior 

technical experts for the Agency in support 

of the Office of the Chief Engineer and 

the NESC. As independent experts, their 

primary role is to resolve complex issues 

in their respective disciplines. Each 

Technical Fellow provided leadership for 

their Technical Discipline Team, which 

collectively form the technical backbone of 

the NESC.

Several NASA Technical Fellows directly 

contributed to the development of new 

space technology roadmaps for NASA’s 

Office of the Chief Technologist, and 

all Technical Fellows participated in a 

comprehensive review of the complete 

set of 14 roadmaps. Responding to the 

Commercial Crew Program Office, the 

Technical Fellows defined appropriate 

space-system standards and requirements 

and also participated in industry partner 

subsystem design reviews. 

As the stewards for their disciplines, 

they sponsored workshops and worked 

to ensure that lessons learned were 

incorporated into the Agency’s engineering 

processes. Additionally, they performed 

state-of-the-discipline assessments for

senior NASA decision makers. The NASA 

Technical Fellows have developed online 

Community of Practice sites on the NASA 

Engineering Network to capture and 

disseminate critical discipline historical 

knowledge before it is lost. They also 

developed short educational videos on 

discipline subtopics for the revamped 

NESC Academy.

The NESC sponsored the Thermal and Fluids Analysis 

Workshop (TFAWS). This long-standing NASA-sponsored 

event was conducted at LaRC on August 15-19, 2011. 

With the continued support of the NESC Passive Thermal, 

Aerosciences, and Life Support/Active Thermal Technical 

Discipline Teams, this Community of Practice workshop 

covered active and passive thermal control, thermal 

protection, fluids, and aerothermal topics. Nearly 200 

registered attendees participated in this year’s workshop, 

including practitioners from industry, government, and 

academia representing NASA, the Department of Defense, 

as well as international participants. TFAWS participants 

met with thermal and fluids software vendors and attended 

a variety of activities, including short courses, software 

training sessions, and multiple paper sessions.

NASA Technical Fellows Contribute to Agency Activities

NASA Technical Fellow for Software, Michael Aguilar, talks with visitors at the

Hispanic Heritage Month event at the National Air and Space Museum.

LaRC’s Kaitlin Liles (right) and the multi-Center TFAWS Steering 

Committee organized this year’s workshop, which featured thermal 

and fluids analysis tools training, paper sessions, and short courses.

NASA/Paul E. Alers

NASA/Ian Batchelder

NASA Technical Fellows Conduct Thermal and Fluids Analysis Workshop

6

NASA Technical Fellow for Avionics, Oscar Gonzalez, takes questions from Isabel

Morales, CNN Español, at the Hispanic Heritage Month event at the National Air and 

Space Museum.
2011 NESC TECHNICAL UPDATE

NESC Overview

Since 2006, the NASA Technical Fellows, in conjunction 

with the NASA Engineering Network (NEN) team, have set 

up online Communities of Practice (CoP) to share technical knowledge across the Agency with the goal of improving the skill sets of its engineers and increasing collaboration across the Centers. The CoPs are part of the 

NEN and are accessible to anyone within the NASA firewall. Engineers can join and align themselves with a community, indicate their areas of interest, and appear on the 

contact list. Any user can find other engineers based on 

their area of interest. The past year has seen several major 

enhancements in the communities. The flight mechanics 

community added a library of portable dynamic models, 

all in a common industry standard format usable on most 

computer platforms. An engineer can pick up and quickly 

start to use a particular dynamic model. It is envisioned 

that other communities will adopt a similar online dynamic 

model library feature. Several communities also adopted 

“Ask an Expert,” which is a feature that allows anyone at 

NASA to ask questions of vetted experts. Questions and 

answers are stored online so others can benefit from the 

exchange. The Technical Fellows encourage engineers to 

join the CoPs, contribute their individual knowledge, interact with peers, and get expert advice. Visit nen.nasa.gov. 

The NESC Academy continues to update its knowledge 

capture and delivery method to shorter, more easily

accessible, and searchable online courses. A new website 

will be implemented in early 2012. Some of the features 

are highlighted below:

•	 Easily accessible short videos (approx. 15 minutes)

•	 Really Simple Syndication feeds (alerts when

 new videos are available)

•	 Full text searching (search content in the videos)

•	 Closed captioning 

Training videos are available from multiple technical 

disciplines and feature:

•	 Discipline-specific training

•	 Lessons learned from NESC assessments

With the exception of the Innovative Engineering course, 

the original instructor-led academy courses are available 

online at http://www.nescacademy.org. These courses 

will also be available on the new site after it is deployed 

using the same URL: http://www.nescacademy.org.

The NASA Engineering 

Network home page 

nen.nasa.gov

The new video player features high-resolution, full-motion video; 

closed captioning with search; user-controlled layout; the ability 

to jump ahead by chapter or slide; and a zoom feature that allows 

magnification of any portion of the slide.

Sharing Technical Expertise Through Communities of Practice

The NESC Academy Goes Virtual

7
2011 NESC TECHNICAL UPDATE

Problem: There has been a renewed focus 

on innovation and technology within NASA. 

This was primarily spurred by the 2011 NASA 

Strategic Plan’s emphasis on the critical need 

for the Agency to invest in next-generation 

technologies and approaches to provide the 

advanced space technology base that is 

essential to NASA’s achieving important goals 

in space exploration and science. Accordingly, 

the Office of the Chief Technologist (OCT) 

led an initiative to draft 14 space technology 

roadmaps (STRs), which lay out the time sequencing 

and interdependencies of high-priority advanced space

technology research and development over the next 5 to 

30 years. 

NESC Contribution: The OCT requested the NESC 

assist in the STR development, each of which was to 

focus on a particular technology area. Several of the 

NASA Technical Fellows and others within the NESC 

organization contributed to this national endeavor by 

serving on the STR development teams in the following 

areas: communication and navigation systems; materials/

structures/mechanical systems and manufacturing; 

thermal management systems; and entry, descent, and 

landing systems. Subsequently, once the draft STRs 

were released, the NESC performed a 

comprehensive and rigorous review of all 14 

draft STRs, utilizing the Technical Fellows 

and their Technical Discipline Teams. The 

NESC STR review process focused on four 

primary areas: identification of technology 

gaps; integration across roadmaps 

(consistent with the Agency's Strategic 

Plan); prioritization of technologies; and 

quantitative ranking of technologies. 

In addition, the Technical Fellows have 

also been performing reviews of technology proposals 

received by OCT. Collectively, they have reviewed multiple 

game-changing technology white paper proposals and 

served on technology proposal review panels. NESC 

personnel were also involved with presentation of the 

draft roadmaps to the National Research Council panels.

Result: The NESC is playing an important role in the 

OCT’s mission to ensure the required space technologies 

arein place to enable our future human and robotic 

exploration missions. In these multiple ways, the NESC is 

supporting NASA’s return to its traditional role of being a 

technology innovator and, as such, a catalyst for national 

economic expansion, increasing the societal impact of our

space program.

Exploration

Technical

Highlights

Space Technology Roadmap Development Support

8
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: NASA initiated capturing system 

requirements at Levels 2 and 3 using 

Computer-Aided Software Engineering 

(CASE) tools in an effort to analyze the 

system behavior across the Ares launch 

vehicle and Orion spacecraft interfaces. 

Computer-Aided Design (CAD) tools perform a similar function for mechanical 

disciplines. An independent assessment 

was requested to capture the lessons 

learned and best use of these CASE tools 

for current and future projects.

NESC Contribution: The NESC is currently 

assessing the use of CASE tools within 

NASA. Phase I of this assessment entailed 

capturing the process and tools used by 

NASA and the Ares launch vehicle and Orion 

spacecraft system development teams. The 

CASE tool process success and gaps were 

identified, as well as the capabilities of the 

selected tools. Phase II will demonstrate 

best practices for the use of these CASE 

tools scoped to a single project, as well 

as scoped for use across projects within 

a major program. A guidelines document 

will be created to capture the results of the 

assessment.

Result: To capture and analyze the behavior 

of the Ares launch vehicle and Orion 

spacecraft interfaces, the text requirements 

for the abort requirements were modeled to 

analyze the communication states between 

the two. Building the executable models 

allowed automated and manual analysis 

and determined nominal and off-nominal 

behavior, incorrect requirements, and missing 

requirements. These modeling techniques 

can be directly applied to current NASA 

and commercial projects.

Problem: The Orion Multi-Purpose 

Crew Vehicle Program requested 

alternate seat attenuation designs be 

developed and analyzed for occupant 

protection in the Orion crew module 

(CM) with primary focus on providing 

improved crew survivability for nominal 

and contingency land landing (CLL). 

Due to the team’s in-depth knowledge 

of the problem and work with isolation 

systems, the NESC had also been 

asked to evaluate design options in the 

crew seat area to mitigate the Ares I 

thrust oscillation (TO) environment and 

evaluate any effect on crew response 

to landing loads. 

NESC Contribution: The assessment 

team consisted of designers, analysts, 

test engineers from multiple Centers 

(including GSFC, JSC, GRC, JPL, and 

LaRC), contractors, academia, and 

other federal agencies. The team built, 

tested, and validated their concept 

for mitigating the launch vehicle TO

event. Coupled loads models for 

launch (using Nastran), landing models with LS-DYNA, 

and Advanced Dynamic Analysis of Mechanical Systems 

multibody dynamics software were used to examine 

the optimal TO isolation frequency that would minimize 

crew loads during all phases of the Orion CM flight, and 

evaluate the system’s response to the environment with 

this hardware in place. A series of component and systemlevel tests were completed to characterize hardware 

performance throughout all phases of flight.

Result: The TO study confirmed the optimal crew 

isolation frequency and testing established the system

performance and damping mechanism value. The NESC 

team found the pallet isolation approach to be appealing 

from a load mitigation perspective. Results indicated that 

the isolation system provided a reduction of dynamic load 

to about 20-30 percent of the input. It is important to note 

that without any isolation, there was dynamic amplification 

of about 125-150 percent of the input acceleration at 

the crew pallet. A design for locking out the isolators to 

prevent increased stroke during the landing event was 

also developed and evaluated during a series of system 

drop tests conducted at LaRC. 

Exploration

The thrust oscillation isolation system under test on two hydraulic shakers in the 

Environmental Dynamics Facility at the Naval Surface Warfare Center, Dahlgren Division, 

Virginia. (Right) Prototype isolation hardware.

U.S. Navy

Ares 

I-X

Development of Orion Crew Seat Energy Attenuation Mechanism Concepts

Mitigation of Software Development Risk Through the Use of CASE Tools

9
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: In 2010, NASA successfully flew the Pad Abort-1 

(PA-1) test flight that demonstrated the ability of the launch 

abort system to perform a pad abort and safely recover the 

Orion crew module (CM). During this flight, many vehicle 

and flight performance parameters were 

measured, including the ability of the 

parachute system to damp and otherwise 

arrest the vehicle’s motion to ensure a 

safe recovery of the spacecraft and its 

astronauts. The parachute performance 

was predicted by project engineers prior 

to this test flight. Post-flight analysis of the 

data showed the flight-observed damping 

to be higher than preflight predictions. 

In addition, free-flight data acquired in 

the LaRC Vertical Spin Tunnel (VST) also 

predicted higher damping similar to flight 

data. 

NESC Contribution: A group of former 

Apollo aerosciences experts teamed with 

the NESC and Orion Multi-Purpose Crew 

Vehicle (MPCV) Program personnel to 

study the CM drogue damping issue. This 

team reviewed the parachute performance 

prediction methods employed by the 

project and evaluated the wind tunnel 

test and PA-1 flight data. The team also reconstructed 

the prediction techniques used by the Apollo Program 

to predict drogue parachute performance. The flight 

and wind tunnel data were analyzed and compared with 

predictions performed using the Apollo 

legacy methodology, and the data were 

found to be in agreement.

Result: The Apollo legacy methodology 

has been recovered and adopted by the 

Orion MPCV Program for their drogue 

parachute performance predictions. The 

NESC team also formulated additional 

VST testing to acquire necessary data for 

the legacy method to further validate its 

applicability and refine Orion CM drogue 

parachute performance predictions.

Lesson Learned: The Agency continues 

to identify engineering methods and 

practices developed during the early 

human space programs that are useful in 

predicting present vehicle performance 

and understanding new data. The 

recovery and documentation of these 

techniques are critical to mission success 

and efficient engineering design.

Problem: The Capsule Parachute Assembly System 

(CPAS) is used to decelerate the Orion Multi-Purpose 

Crew Vehicle (MPCV) crew module (CM) for landing during entry. The subsonic/transonic wake of the CM during heatshield forward descent interacts directly with the 

CPAS and is a critical factor that must be accounted for in 

the CPAS design. The aerodynamic character of the CM 

wake can have a significant impact on the deployment 

sequence and performance of the parachutes. Computational fluid dynamics (CFD) simulations play a key role 

in predicting the aerodynamic behavior of the wake since 

wind tunnel testing of CPAS concepts and configurations 

is costly and limited. However, below Mach 1, CFD prediction of the MPCV wake flow is questionable and thus 

leads to conservative design decisions. As a result, CPAS 

component designs can be oversized to account for uncertainty in the CFD-derived wake aerodynamics. 

NESC Contribution: The NESC team is sponsoring an 

ambitious wind tunnel test at the ARC Unitary Plan Wind 

Tunnel to acquire detailed wake flow measurements behind 

a capsule model. The test will use particle image velocimetry in concert with more conventional test techniques to 

acquire high-fidelity unsteady flowfield data in the capsule 

wake. These data will be used to characterize the flowfield 

behind MPCV-class vehicles and as validation data for the 

CFD simulations used in the CPAS design. In addition to 

ARC, this study relies on multiple NASA Centers, including 

LaRC, JSC, and KSC, to assist in test formulation, model 

design and fabrication, and data acquisition and analysis. 

The model is being designed as a generic capsule so the 

data will be broadly available to the engineering community. The team is also collaborating with the Aeronautics 

Research Mission Directorate (ARMD) to supply data that 

can be used for advanced CFD method development 

sponsored by the ARMD.

Result: Initial results are expected in 2012 with initial report to stakeholders at that time. 

Drogue resultant force acts in line with 

the free-stream velocity (red vector).

CPAS Wake Deficit Wind Tunnel Testing for MPCV-Class Spacecraft

Forward bay cover parachutes

Crew module drogues, reefed (A) and inflated (B)

A

B

CM wake visualization from CFD analysis with locations of CM 

drogues overlaid.

Exploration

Investigation of the Effects of Drogue Parachutes on Orion Crew Module Dynamics

10
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: To lower mass, propellant tanks for the Orion 

crew module (CM) were designed with reduced wall 

thickness. Fracture analysis resulted in the requirement 

that the liquid penetrant nondestructive evaluation (NDE) 

method used to inspect these tanks be capable of finding 

flaws smaller than the 0.050-inch limit previously used in 

the Orbiter Fracture Control Plan (OFCP). Although this 

limit was formally removed with the adaptation of NASASTD-5009, Nondestructive Evaluation Requirements for 

Fracture Critical Metallic Components, there have been 

lingering concerns about using penetrant inspection for 

detecting smaller flaws. The tank vendor’s inspectors 

passed the required probability of detection (POD) 

demonstration test for the smaller flaw sizes using fatigue 

cracked flat panel test coupons. However, JSC engineering 

recommended that the 0.050-inch detection limit still be 

used or that the vendor repeat the demonstration tests 

under more representative conditions. The NESC NDE 

Technical Discipline Team (TDT) was requested to provide 

an opinion on this recommendation. 

NESC Contribution: Experts from the NESC NDE TDT 

reviewed a variety of data relative to the capability of 

penetrant methods. They compared recent penetrant 

POD testing performed by GSFC to results obtained in 

the OFCP test program. They also examined testing that 

showed the detrimental effects of changes in specimen 

orientation and geometry on penetrant POD test results. 

Also reviewed were reports that showed the effects of 

other factors, such as material, surface finish, inspection 

area, and penetrant materials, as well as the limits used for 

penetrant inspections by the U.S. Air Force.

Result: After this data review, the NESC NDE TDT concurred with the recommendation to use the 0.050-inch 

limit or repeat the demonstration tests under more representative conditions. As a result, the wall thickness was 

increased to accommodate the 0.050-inch detection limit. 

However, additional demonstration tests under more representative conditions are being planned as this issue also 

applies to composite overwrapped pressure vessel liners 

being developed for the Orion CM. 

The NESC has continued to build on the successful Max 

Launch Abort System (MLAS) flight test of July 2009 with 

analytical work on a flight-like “objective” system and early 

design of a follow-on flight test vehicle. Launch abort is a 

safety-critical technology crucial to future human launch 

vehicles and, as such, a key element in the success of 

commercial crew providers. It is in NASA’s interest to 

ensure alternate launch abort technologies are explored, 

both to mitigate the development risk associated with government and commercial launch vehicles and to develop 

the in-house expertise necessary for the acquisition of 

commercial systems. Analytical work has narrowed the 

tradespace to an all-propulsive system with active guidance that is effective through all abort regimes, built on 

lessons learned and data derived from the MLAS flight. 

This conceptual design is based on requirements set for 

the Orion launch abort system and is expected to envelop 

those of commercial interests. A baseline concept for a 

vehicle suitable for demonstrating the all-propulsive concept in flight has been completed, with design analysis 

ongoing. Key risks have been identified, and separate 

mitigation projects are underway. The core development 

team is drawn from across the Agency and structured to 

provide hands-on practical experience for early-career 

team members under the guidance of seasoned mentors, 

including NASA Technical Fellows. 

Penetrant indication for tightly 

closed (0.088-inch) fatigue crack 

in a propellant tank.

An MLAS objective system configuration undergoing wind tunnel 

test at LaRC’s Transonic Dynamics Tunnel.

Exploration

Continuation of Launch Abort System Risk Mitigation Efforts

Probability of Detection Limit Implementation on Orion CM Propellant Tank

11
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Exploration Flight Test-1 Radiometer

Feasibility Study

As NASA moves toward space exploration beyond Low 

Earth Orbit (LEO), spacecraft atmospheric entry velocities 

can be over twice that experienced by the space shuttle. 

At these speeds, the entry heating can be dominated 

by shock layer radiation, a heating component which is 

not as important for LEO trajectories and one that is not 

easily or accurately described with present engineering 

models. Physics-based radiative heating prediction 

methods have been developed to overcome some of 

these issues but require flight data for method validation. 

In-flight radiometer measurements are needed to obtain 

data traceable to flight conditions. The Orion MultiPurpose Crew Vehicle Program has undertaken a study 

to determine the feasibility of implementing radiometers 

into the Exploration Flight Test-1 heatshield. The NESC 

performed a complementary assessment to evaluate 

optical system and thermal performance and devised 

a ground calibration test plan for the flight radiometer 

system. As a result of the study, design changes and 

material substitutions were recommended and a designof-experiments-based test matrix, using both arc jets and 

solar thermal facilities, was developed. Augmentation of 

the current design was considered, and design alternatives 

were also provided. 

Orion Crew Module Thermal Protection 

System Margin Study

Problem: The Orion Multi-Purpose Crew Vehicle relies 

on an ablative heatshield thermal protection system (TPS) 

to protect the crew module (CM) and its crew during reentry. This critical component must be designed with 

enough margin to ensure safe return yet be efficient

in mass and thermal performance. The heatshield 

thickness determination process must account for three 

uncertainty sources: trajectory dispersions, aerothermal 

environment predictions, and ablator material property 

effects. The first two sources affect the applied heating 

environment, and the last affects the resulting bond line 

temperature at the ablator-structure interface. The bond 

line temperature margin currently employs a temperature 

reduction derived from the TPS Advanced Development 

Program (ADP) era, where it was based on Phenolic 

Impregnated Carbon Ablator data and analysis from the 

Stardust Program. However, the CM will utilize a different 

ablative heatshield material (Avcoat). Additionally, the 

carrier structure has changed significantly from the ADP 

era, resulting in a reduced allowable bond line temperature. 

The CM heatshield must also be built with higher reliability 

than the Stardust heatshield.

NESC Contribution: The objectives for the NESC’s

Orion TPS Margin Study were to determine the effect of

analysis parameters and system-level uncertainties on 

the TPS heatshield thermal design reliability, determine 

the design reliability of the current heatshield design, and 

provide recommendations for efficient Avcoat ablator arc 

jet testing.

Result: The work was completed resulting in a design-ofexperiments-based arc jet test matrix that was successfully employed during a recent ablator arc jet testing 

campaign. Additionally, the team completed development 

of a heatshield reliability model and identified model 

sensitivity to input parameters.

The Mercury, Gemini, 

Apollo, and Space Shuttle 

Programs made different 

determinations on when 

it was appropriate to fly a 

crew for the first time.

The NESC was requested to develop a framework to 

help Agency leadership and program decision makers 

determine when to allow crewmembers to fly on a new 

human spaceflight system for the first time. Because 

specific approaches and designs may vary significantly, 

prescriptive instructions or thorough checklists cannot 

be developed to apply to all possible human spacecraft 

systems. The decision on first flight with a crew is ultimately 

a judgment call by the program and Agency leadership. To 

aid decision makers, the NESC team developed a generic 

framework for evaluating whether any given program has 

sufficiently complete and balanced plans in place to allow 

crewmembers to fly safely on a human spaceflight system 

for the first time. 

Determining Readiness for First Crewed Flight of New Spacecraft

Illustration of Orion CM during re-entry.

Exploration

12
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: The Orion Multi-Purpose Crew Vehicle (MPCV) 

Program lacked development test data to anchor the 

LS-DYNA analytical model predictions of crew module 

(CM) water landing loads prior to the program’s critical 

design review. These loads are the largest structural mass 

design driver and were predicted by modeling the physical 

interaction of the heatshield and sidewall structures over 

a large range of water landing conditions. Consequently, 

the CM structure may have been oversized and too 

heavy, or undersized, presenting a 

development risk or a crew safety 

risk. In addition, no best practices 

existed for this application in NASA 

and water drop tests were not 

planned by the program until mid2011.

NESC Contribution: An opportunity was identified in late 2009 

to quickly modify an existing fullscale boilerplate CM and use it as 

a pathfinder for the Orion MPCV 

Program’s water drop tests using 

only the variables of vertical velocity 

and entry angle. The NESC water 

drop test data was compared to 

model predictions to provide an 

early assessment and data set to 

inform the program’s structural 

design team. The NESC team 

included contract consultants 

(including retired Apollo engineers) 

and civil servants (including earlycareer engineers) from DFRC,

GRC, GSFC, JPL, JSC, KSC, 

LaRC, WFF, and the U.S. Army and 

Navy. The test, analysis, and data 

evaluation was conducted in two 

phases over a 2-year period. The 

first test phase in February 2010 

comprised 18 vertical drops at 4 

water entry conditions using a crane 

and a test facility at the U.S. Army’s 

Aberdeen Test Center (ATC) in 

Maryland. Onboard instrumentation 

included accelerometers and inertial 

measurement units. Photometric 

targets on the CM surface allowed 

high-speed cameras to capture 

imagery that was processed post-test to characterize 

the CM position and attitude during the water entry. 

Predictions of acceleration response and sensitivities to 

initial conditions were generated using the LS-DYNA model 

at all test conditions and using the program’s existing 

fluid mesh and modeling parameters. For the second 

phase of testing, the CM was modified to add heatshield 

and sidewall-pressure sensors and internal strain gages 

on the primary structure load path. Forty-one drops at 

21 conditions were completed at 

ATC in March 2011. The LS-DYNA 

accelerometer, pressure, and strain 

predictions were generated at key 

test conditions using the program’s 

settings and for a limited number of 

other models and other settings.

Result: Acceleration test measurements were significantly smaller than 

initial LS-DYNA predictions. The 

correlation improved when water and 

structure finite element mesh sizes 

were increased, and the contact 

model for characterizing fluidstructure interaction was initialized 

with test data. The Orion MPCV 

Program’s modelers and structural 

design engineers benefited directly 

from this finding as landing loads

and uncertainties were reduced. 

After accelerated analysis of the 

second phase of test data in 2011, 

preliminary results were provided to 

the program’s structural designers 

and analysts; LS-DYNA modelers; 

guidance, navigation, and control 

(GNC) system designers; and drop 

test planners. The timely briefings and 

test data helped the program validate 

the Exploration Flight Test-1 CM 

landing safety margins, reduce the 

mass of the Orion CM, and improve 

the landing GNC logic design. The 

program’s water drop test team also 

benefited from NESC testing lessons 

learned. A detailed analysis and 

comparison of the test data with LSDYNA predictions will be completed 

by March 2012.

Shock Test Specifications for Reusable Equipment

Space Exploration Technologies Corp. 

(SpaceX) is in the process of qualifying 

their electrical and mechanical components for various shock environments, including pyrotechnic, mortar 

firing, and water impact. The NESC 

was asked to share NASA’s experience with qualifying hardware for the 

Space Shuttle Program and other 

programs. The Space Shuttle Solid 

Rocket Booster (SRB) Project has 

extensive experience in this area. A 

white paper describing their experience 

has been written and released. 

Communications between the NESC 

members and SpaceX have taken

place to share ideas and answer 

questions about NASA experiences. 

NASA documentation on this subject 

has also been provided to SpaceX.

Orion Crew Module Water Impact Testing and Modeling

Both phases of water impact testing were completed at the U.S. Army's Aberdeen Test Center, 

Maryland.

The SpaceX Dragon capsule at KSC.

Exploration

13
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

High-Strain Rate Testing of Reaction Control Thruster C-103 Alloy

In June 2010, a test firing of an orbiter reaction control 

system (RCS) thruster at JSC’s White Sands Test 

Facility resulted in a brittle cleavage fracture of the 

C-103 alloy (89 percent niobium — 10 percent hafnium) 

thruster chamber. The failure analysis related the brittle 

thruster fracture mode to a high-strain rate phenomenon 

reported in the literature. Because there are no C-103 

data relative to the important ductile-brittle behavior 

and C-103 will likely be used for Orion Multi-Purpose 

Crew Vehicle thrusters and other future applications, 

the NESC conducted high-strain rate tests to gain

first-of-kind data for C-103. An impact test was 

developed to achieve the required high-strain rate

to confirm the ductile-brittle transition in C-103. The C-103 

transition occurred at an extremely low temperature

(-160 C) compared to the pure niobium literature finding 

of -50 C. The C-103 data do not fully explain the RCS

thruster room temperature cleavage fracture mode. 

Further testing will be required to gain additional understanding of brittle fracture in this complex C-103 alloy and 

confirm other damage modes, such as embrittlement, are 

not the root cause for cleavage at room temperature.

Carbon-Carbon Silicon Carbide (C/C-SiC) Material Characterization

Problem: The Orion launch abort system (LAS) contains 

an attitude control motor (ACM). The purpose of the

ACM is to safely steer the capsule away from the launch 

vehicle and orient the capsule for parachute deployment. 

The ACM contains eight exhaust nozzles equally 

spaced around the upper portion of the LAS. The motor 

automatically steers the LAS/capsule by controlling the 

thrust produced by each nozzle; this is accomplished 

by rapidly adjusting the opening of the eight valves 

and controlling the exhaust flow of the hot/expanding 

combustion gases. Each of the eight valves consists of 

two critical components: the pintle and the pintle guide, 

which are fabricated from an advanced composite 

material consisting of woven carbon (C) fibers and a

silicon carbide (SiC) matrix (C/C-SiC). Due to the complex 

woven architecture of C/C-SiC and exposure to an extreme 

operating environment (high pressure and temperatures 

greater than 3000F), a thorough understanding of material 

properties is required to ensure a reliable ACM design. 

An independent technical evaluation of C/C-SiC material 

properties was requested by the Orion Multi-Purpose 

Crew Vehicle Program. 

NESC Contribution: The NESC team of materials/

structures/nondestructive evaluation (NDE) discipline 

experts from JSC, LaRC, and academia, with the full 

support of multiple organizations (LaRC and MSFC 

project engineering and Lockheed Martin Corp.; Alliant 

Techsystems, Inc.; and Fiber Materials, Inc.), conducted 

a thorough review of the C/C-SiC database. The purpose 

of this phase I effort was to understand the maturity of the 

C/C-SiC relative to properties, modeling, NDE methods, 

and component testing. As a result of the independent 

review, a phase II testing plan was developed to expand 

the current materials database.

Result: The phase II building-block approach will use 

simple test methods that simulate first-order loads and 

pintle/guide failure locations. The approach will develop 

a key understanding of nonlinear material properties 

required for the breakload-design margin approach, assist 

in validation of the current model, develop NDE methods, 

and develop simple test methods that will be used by the 

LAS development team. 

ACM

Abort

motors

Capsule

Abort

motors

ACM

Orion launch abort system in operation.

Alloy C-103 fracture surfaces: Micrograph shows ductile (left) and brittle (right)—dark areas are flat cleavage regions.

Space Operations

14
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

NASA’s Associate Administrator 

for Space Operations requested 

an independent assessment of 

the proposed mission approach 

to STS-135 using Soyuz for 

crew rescue. The independent 

review focused on assessing any 

change in the risk exposure to 

the STS-135 crew as compared 

to previous space shuttle 

missions since Return to Flight 

(RTF). The following aspects 

were specifically addressed by 

the review team: retention of 

critical space shuttle personnel, 

space shuttle vehicle processing, 

International Space Station 

(ISS) supportability, medical 

considerations, probabilistic risk 

assessment, crew selection and 

training, and crew rescue and 

return. The plan assessed by

the NESC was considered 

feasible and within the scope 

of crew and ISS systems capabilities and provided an 

adequate mitigation approach 

for identified risks. The risk 

associated with the STS-135 crew rescue scenario 

using Soyuz vehicles was within the family of other 

space shuttle crew rescue risk assessments since RTF.

The assessment team submitted 18 recommendations

for consideration to further mitigate risks associated 

with the program’s plan. Both the Space Shuttle and 

ISS Programs successfully implemented 16 of 18 

recommendations prior to STS-135, with the remaining 

recommendations requiring implementation only if a 

contingency shuttle crew support scenario occurred.

Boeing Phantom Works is developing an unmanned air 

vehicle (UAV) known as the Phantom Ray. The prototype 

for this new aircraft design was developed and fabricated 

in St. Louis, Missouri, and had to be transported to 

Edwards AFB, California, for its flight test program. Boeing 

proposed using NASA’s Shuttle Carrier Aircraft (SCA) to 

transport the aircraft and developed support hardware 

to facilitate mounting the Phantom Ray on the SCA. This 

hardware added significant aerodynamic blockage to the 

basic SCA mounting hardware, and there was concern that 

the unsteady flowfield generated by this hardware could 

adversely impact the aft fuselage and tail structure of the 

SCA. Due to budget and schedule constraints, performing 

a comprehensive ground or flight test campaign on the 

baseline and modified SCA was not feasible. Boeing 

planned only one test flight with the UAV attached before 

the long ferry flight to California. The NESC conducted 

unsteady pressure and acceleration measurements on the 

SCA aft fuselage and tail during this flight to determine if 

the induced unsteady flowfield would cause high structural 

vibrations and potential tail damage. The test data showed 

no significant increase in structural vibrations, and the 

Phantom Ray was successfully ferried to Edwards AFB 

where it is undergoing flight tests.

Boeing’s Phantom Ray unmanned aircraft system technology demonstrator became a paying piggyback passenger on NASA’s SCA 

for its ferry flight from St. Louis to Edwards AFB.

Review of Shuttle Carrier Aircraft Air Loads for Phantom Ray Ferry Flight

The Russian Soyuz (top left) is docked to the ISS with Space Shuttle Atlantis docked (right) during 

the STS-135 mission.

Boeing photo/Ron Bookout

Assessment of the SSP Approach to STS-135 with Soyuz Crew Rescue

Space Operations

15
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: The NESC, responding 

to the need to develop and mature 

guidance, navigation, and control 

(GNC) component technology, 

initiated a technical assessment in 

November 2010 to perform a riskreducing technology demonstration 

of an advanced version of the Orion 

crew module vision navigation 

system (VNS). The VNS is a flash 

light detection and ranging (LIDAR) 

relative navigation sensor used 

during spacecraft rendezvous. 

Mounted on a "chaser" spacecraft, 

the VNS pulses its laser to determine 

range and bearing relative to optical 

reflectors mounted on a vehicle 

that is the rendezvous "target." 

This is accomplished by measuring 

the time of flight of a laser pulse to 

the target and reflected back to a 

detector.

In a flash LIDAR system, the laser 

beam is diverged so that the 

illuminated spot on the target surface 

closely matches the field of view of 

the two-dimensional detector array. 

Each pixel in the detector array is 

individually triggered, allowing for 

a measurement of both intensity 

and time of flight (i.e., range) of 

the returned laser pulse. Thus, 

for a single laser pulse, all pixels 

in the scene are illuminated, with 

each pixel providing range and 

intensity information. This results in the generation of a 

full topographic and intensity map of the entire scene with 

each VNS laser pulse. 

This GNC technology demonstration, called the vision 

navigation sensor autonomous rendezvous and docking 

(AR&D) relative navigation experiment (VADRE), was a 

collaborative risk mitigation effort between the NESC, the 

Orion Multi-Purpose Crew Vehicle Program, and the NASA 

AR&D Community of Practice (CoP). The VADRE unit is a 

follow-on and more capable sensor than the sensor test 

for Orion relative navigation risk mitigation (STORRM) 

VNS unit. STORRM was demonstrated on-orbit during 

shuttle mission STS-134 in May 2011. The VADRE unit 

includes new high-performance microprocessors which 

host flight software executing sophisticated image 

processing algorithms. These new embedded algorithms, 

first developed for VADRE, perform pixel processing

(e.g., centroiding), target processing, sensor configuration 

and control, and limit monitoring functionalities.

NESC Contribution: The VNS was baselined as the 

primary rendezvous, proximity operations, and docking 

sensor for the Orion spacecraft. As part of the NESC 

GNC technical assessment, the VADRE unit has been 

assembled at Ball Aerospace and Technologies Corp. (the 

sensor technology provider) from “as-built” engineering 

development unit electronic boards and optical/laser 

subassemblies developed for the Orion spacecraft and 

subsequently transferred to the NESC. Once assembly 

was completed, the VADRE unit was functionally tested 

and then system-level calibrated. The VADRE unit has a 

wide operational range, from 5 kilometers to 2 meters. 

Optical performance was tested and verified against 

multiple known and well-characterized targets spanning 

this operational range.

Result: Following the completion of its testing in 

September 2011, the VADRE unit has become an asset 

for the NASA AR&D CoP. The NESC delivered VADRE 

to the Satellite Serving Capabilities Office at GSFC for 

integration into their Argon AR&D ground test bed. There 

the unit was thoroughly exercised in a series of AR&D 

ground-technology demonstrations.

The data collected from VADRE has been made available 

to the Agency-wide AR&D CoP, where it is being carefully 

analyzed and evaluated. Also, in parallel with the VADRE 

ground demonstrations, plans are being formulated by 

the AR&D CoP to fly this unit to the International Space 

Station (ISS). Collaborative demonstrations of the VADRE 

on ISS over a period well beyond that of the relatively short 

STORRM VNS flight test, will serve to validate relative 

navigation and vehicle position estimation algorithms in 

a realistic operational environment over a broad range of 

dynamic and lighting conditions.

A notional representation of the VNS flash LIDAR illuminating the ISS to determine range and 

bearing relative navigation information.

Space Operations

Vision Navigation System Flight Experiment Development

16
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: In response to NASA and external recommendations, the fire protection systems aboard the 

International Space Station (ISS) are being upgraded. 

While developing a filtering respirator and a fine water 

mist portable fire extinguisher, the ISS technical teams 

identified a need for additional requirements for fire 

protection systems and environments. Specifically, ISS 

needed a set of standard requirements to help design 

firefighting hardware and define common environments 

and procedures for testing and certifying new firefighting 

systems. The standard requirements should also apply to 

future crewed spacecraft.

NESC Contributions: An initial team of experts from 

around the Agency was formed and has begun working 

on standard requirements. A list of personnel outside 

NASA with expertise in emergency response and 

developing standards was also compiled. The intent is 

to engage some of these experts in the development of 

the technical content for the standard requirements. The 

NESC representatives will support peer reviews of the 

fire extinguisher test plan and the technical content for 

new design requirements for fire protection systems. The 

NESC is also providing statistics expertise to support the 

development of baseline test configurations, test data 

reduction and analysis, and fire extinguisher optimization.

Result: Instead of developing a new NASA standard, an 

approach to update the existing fire protection system 

section of NASA-STD-3001, Volume II (Human Factors, 

Habitability, and Environmental Health), and to add a new 

section to the Human Integration Design Handbook was 

adopted. A separate handbook specifically for portable fire 

extinguishers may be developed. The team is developing 

technical content for the standard and the handbook. 

Clearly documented requirements, rationale, test plans, 

and best practices from one generation of spacecraft 

systems help prevent “reinventing the wheel” when 

upgrading those systems on existing spacecraft as well 

as designing new systems for future crewed spacecraft.

Problem: Single operation pyrotechnically operated 

valves (pyrovalves) perform critical propulsion system 

functions for payloads onboard expendable launch vehicles (ELVs). When hazardous propellants such as hydrazine (N2H4) or nitrogen tetroxide (N2O4) are used, concerns 

increase for the safety of personnel when they are working 

near the payload. Additionally, payload safety reviewers 

and spacecraft programs have not always agreed on the 

number of mechanical inhibits that pyrovalves represent 

nor on the credibility of leakage as a failure mode. These 

issues, and how control systems and software inhibits 

are implemented, have caused concerns and changes to 

spacecraft systems late in the launch-processing flow. 

NESC Contribution: An assessment by subject-matter 

experts is under way to give clearer guidance for evaluating pyrovalve mechanical integrity, risk of inadvertent ignition, and overall reliability of the valve and control systems.

Result: A draft set of minimum requirements for manufacturing and testing has been developed. Potential leak 

paths in parent-metal pyrovalves have been evaluated 

with finite element analysis (FEA). Leakage was deemed 

not credible for the common 3⁄8-inch, 1⁄2-inch, and 3⁄4-inch 

models studied to date. Nondestructive evaluation also 

helped validate the FEA on the 3⁄4-inch model and showed 

that the configuration was robust. The 3⁄4-inch valve has a 

maximum expected operating pressure of 750 pounds per 

square inch gauge (psig) and no evidence of deformation 

was measured after being subjected to 3600 psig. Evaluation of mechanical integrity for other pyrovalve models, 

risk of inadvertent operation, and reliability of pyrovalves 

and controls is in progress. The assessment will provide 

guidance to assist the ELV payload safety community in 

developing payload safety policies regarding pyrovalves.

John Anderson (left) and Steve Woods of WSTF discuss a pyrovalve 

stress analysis, performed to evaluate safety margins.

An ISS Expedition 20 flight engineer conducts an inspection on portable fire extinguisher and portable breathing apparatus equipment.

Space Operations

Standard Requirements for Fire Protection Systems on Crewed Spacecraft

Pyrovalve Reliability Assessment for Expendable Launch Vehicle Payloads

17
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: Following the scrub for the initial launch 

attempt of STS-133, a crack was observed in the foam 

covering the intertank stringer near the intertank-to-liquid 

oxygen tank flange. Subsequent detailed examinations 

determined four stringers were cracked, which produced 

both ascent debris and structural (buckling) concerns. 

The investigation, led by the External Tank (ET) Project, 

determined the primary contributors were the use of a 

material susceptible to unstable crack growth due to 

anomalous thermal/mechanical processing, and high 

assembly stresses resulting from stringer fabrication and 

attachment characteristics.

NESC Contribution: The NESC augmented the ET 

Project Investigation Team with the addition of subject 

matter experts in the areas of mechanical loads, thermal 

and structural analysis, materials testing, nondestructive 

evaluation (NDE), statistical analysis, and human factors. 

In addition, the NESC team conducted independent 

structural failsafe and critical flaw size analyses, material 

thermal treatment sensitivity and mechanical strength 

studies, and statistical data analyses of material and 

subscale testing.

Result: The ET Project corrective actions were to repair 

cracked stringers with doubler plates, increase stringer 

capability with the installation of radius blocks, and 

conduct a tanking test followed with NDE to verify stringer 

integrity. The NESC provided an in-depth and independent examination of the ET Project plans and

generated critical material property data for the 

understanding of the most probable origin of the thermal/

mechanical processing anomalies.

Lessons Learned: The continued emphasis on 

maximizing shuttle payload resulted in the replacement 

of the intertank stringer material from moderate strength/

high ductility to a high-strength/moderate-ductility alloy. 

This material substitution resulted in an approximate 

50-pound weight reduction. However, the addition of the 

radius block modification negated the weight savings. The 

lesson learned was that a systems consideration should 

be taken with any material substitution to ensure that a 

potential weight reduction is not replaced with increased 

manufacturing problems and/or operational issues. 

STS-133 External Tank Intertank Stringer Crack and Repair

Microphone Phased Array for Measuring Launch Vehicle Lift-off Acoustics

The acoustics generated during the liftoff of a launch vehicle have historically 

been characterized via single-point 

sensors, which provide acoustic levels 

at discrete points. A microphone phased 

array has the potential to measure 

acoustic levels over the entire launch pad 

and vehicle. The NESC is conducting an 

assessment to develop and demonstrate 

this capability. This year, acoustic data 

collection with a phased array on the 

subscale Ares I liftoff acoustic test 

article was completed. Preliminary 

data analysis shows that, the array can 

survive repeated exposure to the harsh 

liftoff environments and that with proper 

array design, the acoustic sources of 

primary interest can be mapped with a 

single microphone array. Opportunities 

to demonstrate the technique on a fullscale launch vehicle are being pursued.

(From left) Robert Mosher, Roberto Garcia, and 

Jayanta Panda in front of the acoustic phasedarray sensor tower, viewing the Ares I scale 

launch vehicle and launch pad model. 

Visible-light and infrared (inset) photographs of ET foam crack.

Space Operations

18
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

The NESC, at the request of the NASA Commercial Cargo and 

Crew Program Office (CCCPO), evaluated the risks associated 

with conducting the new Orbital Sciences Corp. (OSC) Taurus 

II launch vehicle first-stage qualification test on the launch pad 

at WFF. The Taurus II system is to be used for International 

Space Station resupply. To evaluate the risks in conducting the 

stage qualification tests, the NESC extensively reviewed OSC 

stage qualification test plans and design analysis documents; 

performed computational fluid dynamic, acoustic, and thermal 

analyses; and obtained test data from Taurus II AJ-26 single 

rocket engine tests conducted at SSC. The NESC independent 

assessment team identified four potential hazards, including 

inadvertent launch, on-pad fire/explosion, damage to the 

pad infrastructure, and damage to the stage qualification test 

article. Each hazard was rated for likelihood and consequence. 

Recommendations for additional structural and thermal analyses 

of the test-unique stage/pad interface hardware were given to 

OSC, CCCPO, and WFF safety organizations.

Nondestructive evaluation (NDE) of the welds on the launch 

mounts of the Taurus II launch pad at WFF was performed using 

ultrasonic testing (UT) instead of the specified radiographic (RT) 

method. This was done because of the difficulty of inspecting 

the thick sections of the mounts with RT. The NESC was asked 

to determine whether the UT provided an acceptable inspection. 

NDE Technical Discipline Team experts reviewed the NDE 

inspection reports and concluded that UT could be submitted as 

a waiver to the RT requirements. However, they noted numerous 

deficiencies in the UT inspection reports and recommended 

that an audit be performed or the welds be re-inspected. The 

project accepted the recommendation, and the structure was 

re-inspected by a different NDE contractor.

Launch Pad Acoustic Suppression Ring Weld NDE 

Taurus II On-Pad Stage Testing Plan Study

Problem: Astronauts performing 

extravehicular activities (EVAs) 

on the International Space 

Station (ISS) are exposed to 

risk of decompression sickness 

when transferring from the cabin 

atmosphere of 14.7 pounds 

per square inch (psi) to the suit 

operating pressure of 4.3 psi. 

This risk is mitigated by the use 

of oxygen prebreathe to wash 

out nitrogen from the astronaut’s 

bloodstream, prior to each 

EVA. Since 2006, the primary 

prebreathe method used on ISS 

is the “campout” protocol, where the EVA astronauts 

campout the night before the EVA in the airlock at a 

reduced atmospheric pressure of 10.2 psi. This procedure 

reduces the in-suit prebreathe time on the day of the EVA, 

but isolates the crew in the airlock for over 8 hours. To 

provide an alternative protocol, JSC’s Space and Life 

Sciences Directorate (SLSD) developed the in-suit light 

exercise (ISLE) prebreathe protocol. The ISLE prebreathe 

protocol includes a 50-minute period of light exercise

in the spacesuit and has some 

operational benefits, including 

eliminating the overnight isolation 

in the airlock.

NESC Contribution: The NESC 

assisted the JSC SLSD in forming 

a peer review committee of experts 

in decompression sickness risk 

and the operational aspects of 

EVA to assess the proposed use 

of the ISLE prebreathe protocol. 

The peer reviewers looked at 

physiological data from ground 

trials of the prebreathe protocol, 

operations data including EVA 

prebreathe history, and the operational details of the 

planned ISLE implementation on ISS.

Result: The peer review committee found, based on all 

of the data reviewed, that the ISLE prebreathe protocol 

was acceptable for use on the ISS. The ISLE protocol was 

subsequently used during the third EVA performed during 

the STS-134 mission and during the STS-135 EVA. Both 

EVA crews endorsed the continued use of ISLE on ISS.

In-Suit Light Exercise Prebreathe Protocol for Extravehicular Activities

Expedition 28 crewmember, Mike Fossum, in the ISS 

Quest airlock prior to an EVA during STS-135.

Artist’s rendition of a Taurus II on the launch pad at WFF. 

Orbital Sciences Corp.

Space Operations

19
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: The International Space Station (ISS) 

experienced a failure of control moment gyro (CMG-2) 

and an anomaly in CMG-3, which were both replaced and 

returned for examination. Analysis of the CMG issues is 

continuing.

NESC Contribution: Technical experts selected from the 

areas of materials; bearings; lubrication; and guidance, 

navigation, and control (GNC), who participated 

in the original assessments, continued to track 

recommendations made in those assessments. Previous 

assessments performed by the NESC on the CMG-1 

failure and CMG-3 anomaly included support from the 

NESC Mechanical Systems and GNC Technical Discipline 

Teams (TDTs). When CMG-3 was disassembled upon 

return from the ISS, dewetting of the bearing surfaces 

was noted. While no such observation was made on

the CMG-1 hardware, dewetting continues to remain 

on the fault tree as a possible contributor to the CMG-3 

anomaly observed in flight, resulting in its shutdown and 

eventual return to Earth. In the course of addressing this 

possible contributor, a test was run using the CMG-3 flight 

bearings and flight-like electronics. Periodic inspection 

of the bearings was performed to note whether dewetting was produced in the test. After a few months 

dewetting was noted on three balls in one of the bearings. 

Failure of the test occurred shortly thereafter, but the 

interpretation of the results was marred by the excessive 

concentration of contaminant introduced to produce the 

dewetting and the previous testing performed on the 

bearings used in the test, calling into question the validity 

of the results. The current NESC assessment focuses 

on evaluating the credibility of dewetting as a possible 

contributor to root cause.

Result: Testing is planned to better understand the 

performance effects and associated risks, if any, of the 

wax contaminant known to be present in the four CMG 

assemblies currently in operation on the ISS.

During developmental testing of a space shuttle orbiter’s 

orbital maneuvering system/reaction control system, 

damage was sustained to the L1L thruster. The NESC 

was requested to provide an independent technical 

review of the failure assessment, fault tree structure, 

scenario generation, thermal and flow analyses, and 

flight rationale generation. The NESC team provided 

independent evaluations, which included thermal and onedimensional draining model and Zot (oxidizer and/or fuel 

passages) analysis. The NESC team identified fault tree 

enhancements that described the proximate causes and 

provided qualitative and quantitative analysis predictions, 

which further substantiated the most probable scenario 

(i.e., leaking oxidizer valve and migration of oxidizer into 

the fuel passages/manifold leading to detonation and 

damage). The NESC team concurred with the proposed 

flight rationale that this type of failure could not occur 

during flight as the following conditions would not exist: 

a leaking oxidizer valve, horizontal orientation at 1g, and 

ambient temperatures. As a follow-on to the Orbiter Project 

investigation, the NESC conducted high-strain-rate tensile 

testing of nozzle material extracted from a thruster with 

similar exposure time to the unit involved in the incident. 

This testing revealed that the detonation was not the sole 

contributor to the brittle (cleavage) fracture observed in 

the test failure.

International Space Station Control Moment Gyro Assessment

Orbital maneuvering system showing the L1L thruster (circled).

The CMG-3 was replaced during STS-118 mission to the ISS.

Space Operations

Space Shuttle Orbiter L1L Thruster Investigation Support

20
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Entry, descent, and landing (EDL) flight simulations are 

typically developed for specific tasks. In many cases, 

once the effort is completed, the simulation models are 

not adequately documented or retained. Many projects 

or studies requiring EDL would benefit from high-fidelity 

simulations with a library of validated and documented 

models. In this activity, the NESC team converted and 

archived a number of current and historic EDL models 

and scripts into a secure user library with appropriate 

user documentation and test cases. The team also 

developed several new models currently of interest in 

the EDL community. As a whole, the models included 

aero-dynamic and mass models of entry vehicles,

atmospheric and gravity models of planets and moons, 

guidance and control algorithms, a multimode Kalman 

navigation filter for onboard state estimation, aerodynamic uncertainties for dispersion analyses, guidance 

models for aerocapture and aerobraking, and several 

basic attitude-control models.

Products of this activity are expected to help define the 

required architectures and investment strategies to aid 

a wide range of future robotic and human exploration 

missions. Overall, having this EDL flight simulation 

capability readily available increases the ability of the 

Agency to evaluate a wide range of EDL systems and 

problems in systems analysis studies, preliminary

design, mission development and execution, and timecritical assessments.

Flyaway

Parachute 

descent

Powered descent

Sky Crane

Heatshield separation

Deploy 

parachute

Entry balance mass jettison

Radar activation and mobility deploy

MLE warm-up

Backshell separation

Cut to four engines

Rover touchdown

Rover separation

Mars Science Laboratory entry, descent, and landing sequence.

Simulation Framework for Rapid Entry, Descent, and Landing Analysis

Rover touchdown just before SkyCrane fly away.

MSL entry into Mars atmosphere.

Science

21
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Independent Review of CoNNeCT Antenna Gimbal Structural Analysis

An independent review of the structural analysis and 

modeling of the antenna pointing subsystem integrated 

gimbal assembly (IGA) of the Communications, Navigation, 

and Networking Re-Configurable Testbed (CoNNeCT) 

was performed.

An NEI Nastran finite element model of the CoNNeCT 

antenna IGA was developed by Sierra Nevada Corp. 

(SNC). The NESC team peer reviewed this finite element 

model. The NESC raised issues regarding fastener 

modeling, baseplate boundary conditions, modeling 

related to gussets, and interfacing linear and quadratic 

elements. The responses to the issues raised by the 

NESC team were adequately addressed by SNC. The 

contractor has implemented the team’s suggestions

and corrected the identified model deficiencies. The

model was revised, following most of the NESC 

suggestions except for one load case where a conservative 

approach was recommended. For this load case, the 

project decided that its approach was still low risk.

The new margins of safety were evaluated and verified to 

be satisfactory except for this one load case.

The GRC Communications, Navigation, and Networking ReConfigurable Testbed (CoNNeCT) 

Project experienced technical 

issues with two aspects of its 

spacewire implementation. The 

first issue occurred during the 

CoNNeCT functional testing and 

affected the cable; the second 

issue involved the implementation 

of the spacewire protocol. A 

request for NESC support to 

assist in identifying root cause 

and corrective action recommendations was 

successfully completed with the identification of the

causes for both issues, respectively: (1) Cable harness 

manufacturing issues and (2) peripheral component 

interconnect (PCI) software driver incompatibility.

The cable harness issue was resolved after a review 

of the manufacturing process and subsequent 

recommendation to perform a 

more thorough vacuum bakeout to remove residual alcohol 

used in the cleaning process as 

well as implementing larger cable 

bending radius routing to avoid 

internal cable compression. The 

protocol problem was resolved 

using a PCI mezzanine card 

(PMC) bus analyzer on loan 

from GSFC. With the PMC bus 

analyzer, GRC was able to identify 

the anomalous PCI transactions 

in the design associated with two READ direct memory 

access commands between the single board computer 

and the dynamics engineering spacewire board being 

processed at the same time, resulting in the observed 

lockup condition. Subsequent software updates were

able to correct the conflict in order to proceed with 

remaining testing.

CoNNeCT antenna 

gimbal finite element 

model used in the 

analysis.

CoNNeCT Spacewire High Data Rate Anomaly Investigation

Spacewire printed circuit board.

Science

22
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: Recently the science operations of the Hubble 

Space Telescope (HST) have been compromised by an 

on-orbit anomaly called the attitude observer anomaly 

(AOA). The HST experienced occasional losses of lock 

during fine guidance sensor (FGS) guide star acquisitions, 

threatening a potential loss of science. These failures 

were associated with an increasing disparity between 

the FGS-derived estimates of gyro bias calculated in the 

day portion of the orbit and those calculated in the night 

portion. 

NESC Contribution: In February 2011 GSFC formed an 

Anomaly Review Board (ARB) to investigate this anomaly. 

Members of the NESC Guidance, Navigation, and Control 

Technical Discipline Team served as members of this 

board, contributing to the formulation of recommendations 

for resolving, or at least mitigating, the AOA phenomena. 

The NESC identified and provided HST gyro subject 

matter experts from outside NASA to support the ARB’s 

deliberations. These were retired engineers from the gyro 

vendor who had unique hands-on knowledge regarding 

the HST gyro design, build, and test processes. Members 

of the NESC Engineering Statistics Team analyzed and 

evaluated HST telemetry data, looking for AOA indicators, 

trends, and patterns. The NESC also performed orbital 

analyses to identify the source of an unusual oscillation, 

with a 47-day period, that was superimposed on a 

secular increase in the AOA amplitude. The source of 

the oscillation was determined to be cross coupling into 

a failing gyro from a second otherwise healthy gyro that 

was exceptionally sensitive to the Earth’s magnetic field.

Result: The ARB initially focused on the thermal control 

of six degrees of freedom floated rate-integrating gyros 

that function as the HST’s primary pointing reference. 

The ARB found that the AOA was caused in part 

by the inability of the gyro’s primary low-bandwidth 

heater controller to suppress the thermal “heat 

pulse” caused by main bus voltage transients, which 

typically occur at the spacecraft’s eclipse exit (day) 

and entry (night). Upon the ARB’s recommendation, all

six HST gyros were switched in July 2011 to

their secondary high-bandwidth heater controllers. 

Operating the gyros on the secondary heater controllers, 

which have a bandwidth 10 times higher than the 

primary heater controllers, reduces their thermal 

transients. Although the root cause mechanism had not 

been definitively identified by the ARB at that time, the 

reconfiguration to the secondary heater controllers proved 

to be an effective on-orbit mitigation of the AOA.

The ARB continued its investigation into the AOA root 

cause using a detailed fishbone analysis approach. The 

ARB subsequently linked the AOA to the corrosion of the 

multiple flex leads, each the diameter of a human hair, 

which serve as the internal electrical connection to the 

gyro float. Therefore, there is the potential for the AOA 

to occur in any HST gyro. The ARB concluded its work 

in September 2011 and has recommended that the HST 

Project minimize main bus voltage transients in order 

to limit gyro flex lead degradation and, by association, 

the AOA. This includes reducing occasional large loadshedding events, such as those which occur during 

spacecraft safing events, as well as minimizing the twice 

per orbit day/night power transients. As a longer term fix, 

the ARB recommended the addition of new open-loop 

AOA compensation in the HST’s onboard attitude control 

flight software. The NESC is continuing to support the 

HST Project by updating gyro life predictions and by 

considering the development of a new multidisciplinary 

model of the gyro flex lead degradation physics. 

Fermi On-Orbit Slip Ring Anomaly

The NESC provided technical support for an investigation of a Fermi on-orbit coarse sun sensor (CSS) anomaly 

believed to have been caused by a solar array slip ring 

assembly (SRA) malfunction. The SRA was manufactured 

in Europe and sold as heritage equipment from the Swift 

spacecraft. From review of the on-orbit telemetry, the 

team methodically ruled out component anomalies other 

than the SRA. Minor operational changes to preserve slip 

ring life were recommended and implemented. To date, 

the anomalous behavior has stabilized and the spacecraft 

is fully functional.

Hubble Space Telescope Attitude Observer Anomaly Investigation

An HST gyro showing the heaters (2 bands on left) and 

secondary temperature sensor (on right).

An 

illustration of 

the Fermi slip 

ring design.

Science

23
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Due to the high thrust-to-mass ratio of the main engine 

to the mass of the spacecraft for the Lunar Atmosphere 

and Dust Environment Explorer (LADEE), many of the 

guidance, navigation, and control (GNC) parameters 

associated with the thrust vector alignment and centerof-gravity tolerance and control are much tighter than 

typical spacecraft. Although achievable, these tighter 

tolerances do require special dynamic spin balancing and 

special attention to analyses and integration processes to 

meet these requirements. The NESC is currently providing 

technical support to the LADEE Project Alignment 

Working Group, and will provide guidance and monitor the 

activities associated with achieving these GNC-related 

requirements, to help ensure mission success. The LADEE 

spacecraft integration activities will start in the winter 

of 2011 and continue into 2012. LADEE is scheduled to 

launch in 2013.

Assessment of the CrIS Instrument Structural Frame for JPSS

Problem: The Joint Polar Satellite System (JPSS) crosstrack infrared sounder (CrIS) instrument utilizes an 

aluminum-beryllium-metal-162 (AlBeMet) structural frame 

to mount a precision interferometer and beryllium (Be) 

optical bench, as well as electronics, thermal control, and 

in-situ calibration components. Electron-beam (e-beam) 

welding was the baseline approach to join four AlBeMet 

parts into a single frame. After a successful study using 

welded AlBeMet test coupons, e-beam welding runs were 

conducted using full-sized aluminum (Al) frame mockups 

with AlBeMet weld interfaces. Initially, AlBeMet weld 

joints were performed on four mockups and inspected 

for defects using x-ray computed tomography imaging. 

Inspections revealed unacceptable weld penetration, 

porosity, and cracks. Improvements to weld parameters 

and fixture restraints yielded acceptable weld penetration 

and porosity in four additional weld mockups; however, 

cracks persisted in certain weld areas.

NESC Contribution: The NESC was requested to assess 

the baseline e-beam welding process to determine

if a flightworthy welded frame was achievable for JPSS-1

and provide recommendations on alternative frame 

materials and manufacturing processes to mitigate CrIS 

development risks. The NESC reviewed documents from 

prior CrIS frame design, manufacturing readiness, and 

test reviews; conducted a technical interface meeting on 

the baseline welded AlBeMet frame with the CrIS Project; 

and reviewed a trade study by the CrIS contractor on 

12 alternative frame materials and construction options.

The NESC provided preliminary and final risk assessments, findings, observations, and recommendations to 

the CrIS Project.

Result: Scanning electron microscope investigation 

of crack samples taken by the CrIS contractor revealed 

liquation cracking in partially melted zones of Be and 

liquid Al during AlBeMet welding as the defect cause. 

Further weld improvements are needed to control liquation 

cracking in welded AlBeMet. Two alternative approaches 

for the CrIS frame were recommended by the NESC to 

provide JPSS-1 risk mitigation. The primary alternative 

is a one-piece frame machined from a single AlBeMet 

billet, which is a larger AlBeMet structure than previously 

machined and requires improved billet screening and 

machining controls. A backup alternative is a one-piece 

frame machined from a single Al billet; but the Al frame 

option exhibited a dynamic interaction at 144 Hz (five 

times higher vibration levels at the interferometer than the 

AlBeMet frame), which requires design improvements to 

alleviate. The CrIS Project decided to proceed with the 

single-piece AlBeMet frame.

Lunar Atmosphere and Dust Environment Explorer GNC Parameter Support

CrIS frame during x-ray computed tomography inspection.

An illustration of the LADEE spacecraft.

Science

24
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Analysis of Flight Vibration and Shock

Environments for Black Brant X Upper Stage

The NESC investigated the flight vibration and shock 

environments for two recent sounding rocket launches. 

Accelerometer data from the flights were analyzed and 

informal reports provided to the NASA sounding rocket 

operations contract at WFF. Each vehicle had a Terrier

first stage and a Black Brant second stage. The Black 

Brant motor was found to have a motor pressure oscillation 

at 110 Hz, with integer multiples thereof. This effect is 

apparent toward the end of the Black Brant burn from 35 

to 45 seconds. The oscillations did not setup in a pure 

sinusoidal or sinusoidal sweep pattern, but were rather 

found to have a narrowband characteristic.

The NESC also analyzed a shock event at ~0.15 seconds 

from a total of six flights. The shock is most likely due 

to a “jointslip” effect between the connected modules. 

This effect is a variant of “stickslip,” in which the static 

friction is higher than kinetic friction. The slip is driven by 

rigid-body acceleration, as Terrier-Black Brant vehiclestypically accelerate from zero to 7g from zero to 0.15 

seconds and the rigid-body acceleration compresses 

the vehicle. The average jerk is very high at 47g/sec. 

Thus there is a rapid accumulation of strain energy in the

vehicle and its joints. The shock pulses represent the 

release of this strain energy as the vehicle tries to settle 

into a new equilibrium condition.

Design Concept for New Sounding Rocket 

Sustainer Motor

Problem: NASA’s Sounding Rocket Program (SRP) 

provides low-cost opportunities to conduct leading edge 

research into many areas of interest, throughout and above 

the Earth’s atmosphere. The SRP workhorse motor, used 

alone or as part of a multistage rocket, is a 1960s design 

manufactured in Canada. This motor has a long history of 

reliable performance, but over the last several years, its 

reliability has decreased significantly for various reasons. 

A new design that takes advantage of modern design and 

production practices is needed to ensure the reliability of 

sounding rocket missions.

NESC Contribution: The NESC is developing a conceptual design of a new sounding rocket motor that meets 

the performance and cost requirements of the SRP. The 

design team consists of members from WFF, NESC, KSC, 

and MSFC. Additionally, propellant characterization testing is being done in partnership with the U.S. Army, and 

opportunities for motor casting and testing are being pursued with the U.S. Navy. The goal is to generate a government-owned design that will be produced in economical 

lots by private industry.

Result: The design team has generated a conceptual 

design that meets the performance requirements and 

ease-of-manufacture goals. All design and manufacturing 

parameters are well within current capabilities and common practice. Cost estimates are being generated for the 

next phase of the development effort, which calls for three 

ground tests and three flight tests, as well as for the production motors. Sponsorship is being solicited for the next 

phase of the motor development.

The Black Brant sounding rocket motor (black upper stage), 

operational since the 1960s, is the workhorse of NASA’s Sounding 

Rocket Program.

Science

25
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: The Mars Science Laboratory (MSL) Project 

is using pyrovalves with stainless steel primer chamber 

assemblies with a “V” channel shape (V-PCA) rather 

than the heritage aluminum design with a “Y” channel 

shape (Y-PCA). The design was changed to reduce flame 

channel melting/erosion, eliminate potential obstructions 

at the channel intersection, and reduce variability. MSL 

qualification testing of the V-PCA design demonstrated 

faster booster ignition and little or no melting/erosion. 

However, further testing was needed to quantitatively 

compare the two designs. 

NESC Contribution: The WSTF developed a specialized 

method to compare the two PCAs. The method used 

high-speed infrared pyrometers (6μ s response) and 

video cameras (20,000 frames per second) to observe 

the underside of the booster cover (propellant interface) 

through a sapphire window. Other tests also evaluated 

the effects of larger diameter flow channels and varying 

skews between the firing of the redundant initiator firings.

Result: The new PCA design delivered an average 

propellant interface peak temperature of 315C (600F) 

higher than the aluminum design in about one-half the 

time and produced pressures that were several thousand 

psi greater. However, dual simultaneous firings of both 

PCA types reduced the maximum temperature several 

hundred degrees below the threshold needed to ignite the 

booster. This potential failure mode occurred even with 

flow paths with four times the original cross-sectional 

area. These data will help future NASA projects to properly 

evaluate the selection and use of PCAs.

The NESC is providing an independent assessment of 

the James Webb Space Telescope (JWST) near infrared 

spectography (NIRSpec) microshutter subsystem life test 

results. Although the mechanisms’ performance met the 

two times life requirement, debris noted during post-test 

inspection is a concern for instrument operation. The 

NESC team, consisting of KSC, GRC, MSFC, ARC, GSFC, 

JSC personnel, and contractors, is evaluating the effect of 

contamination on the instrument’s performance as well as 

conducting a series of tests to determine when, in the life 

of the unit, debris generation begins. In addition, the team 

will recommend a modification to reduce the amount of 

contamination, which will be based on engineering test 

data. The evaluation and recommendations are expected 

to be complete by the end of 2011.

James Webb Space Telescope NIRSpec Microshutter Subsystem Investigation

Pyrovalve Booster Interface Temperature Measurement

Benjamin Gonzalez, 

Jacobs Scientist 

(seated) shows 

close-ups of postfiring PCAs to 

project leader, Steve 

McDougle (left), and 

assessment lead, 

Regor Saulsberry.

NIRSpec microshutter subsystem life test unit.

Science

26
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: The NASA Standard for Models and Simulations 

(NASA-STD-7009), developed in response to the

Columbia Accident Investigation Board recommendations and approved in July 2008, is still not widely 

implemented or well understood within the Agency. 

Reasons for its slow adoption include its broad applicability 

across modeling and simulation (M&S) domains (i.e., 

it is not specific to any particular M&S application area 

or type), some of its terminology and intentions are 

not ubiquitously understood, and reticence to accept 

additional requirements that could add workload and/or 

cost to a project. 

Inconsistent understanding of M&S risk and credibility 

assessment approaches also exists throughout the 

Agency. M&S risk assessments are used to determine 

which models and simulations influence critical decisions. 

M&S credibility assessments are used to communicate 

the credibility of M&S analysis results based on factors 

such as verification, validation, input pedigree, results 

uncertainty quantification, results robustness, use history, 

M&S management, and people qualifications.

NESC Contribution: The NESC team, consisting of 

M&S practitioners from nine NASA Centers, developed 

a handbook that includes a checklist with explanations, 

definitions, and examples, enabling programs and 

projects to more effectively implement the requirements 

and meet the fundamental intent of NASA-STD-7009. The 

primary goals of the M&S standard and handbook are to 

provide consistent M&S reporting, terminology, and risk 

assessment approaches and to ensure the credibility 

of M&S analysis results is properly conveyed to those 

making critical decisions. The team also worked with 

early adopters of NASA-STD-7009 to clarify requirements 

and document recommended practices.

Result: A growing community of M&S practitioners is 

using NASA-STD-7009 to guide the implementation of 

their projects and assess the adequacy of their products. 

Two early adopters are the Orion Multi-Purpose Crew 

Vehicle Program and the Human Research Program. The 

Commercial Crew Program has also included specific 

requirements to perform risk and credibility assessments 

for any critical M&S. The availability of a draft handbook 

was invaluable to increasing the use and understanding 

of NASA-STD-7009. The personnel benefiting from the 

handbook include M&S tool developers and operators, 

systems analysts, decision makers using M&S analysis 

results, and independent reviewers of M&S products. 

The effort has also reinforced the need for technical 

discipline-specific guidelines to assist in implementation 

of the concepts of this standard within specific types of 

M&S. Specific examples, explanations, and recommended 

practices are crucial to understanding the requirements 

and intent of NASA-STD-7009.

Future spacecraft, such as those participating in the Google Lunar X-Prize, 

may be landing near and visiting historic 

lunar locations such as the Apollo Program 

landing sites. The NESC provided support 

in creating guidelines for protecting

these sites from damage caused by 

either landing close to them or by making 

contact with or contaminating the artifacts

located therein. In addition, future missions 

may provide the opportunity to observe

any effects on the materials and hardware left on the surface of the Moon. 

These items have endured 4 decades of 

solar radiation, micrometeoroids, +250 F 

to -300 F temperature extremes, and lunar 

dust. The NESC team provided specific 

suggestions concerning how to use 

artifacts from these sites as engineering 

witness plates to understand long-term 

exposure to the lunar environment.

Verification

M&S

Development

M&S

Operations

Supporting

Evidence

M&S Results Credibility

Validation M&S

Management

Use

History

People

Qualifications

Results

Uncertainty

Input

Pedigree

Results

Robustness

Apollo 16 landing site showing lunar module and lunar rover.

NASA Models and Simulations Handbook Development

Support to Google Lunar X-Prize for Apollo Landing Site Preservation Recommendations

Factors in a credibility assessment of M&S analysis results.

General

27
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: GRC’s Icing Research Tunnel (IRT) is one of 

NASA’s unique aerodynamic test facilities. It is one of the 

largest icing wind tunnels in the world and is constantly 

in high demand due to this unique capability. One of the 

tunnel’s main features is a large external balance and 

turntable system. The tunnel needs to update this force

measurement system (FMS) to increase the force and 

moment measurement accuracy and to improve facility 

throughput. This FMS was designed and built in the 

early 1980s by civil servants who have since retired and 

GRC no longer has in-house knowledge of how best to 

upgrade the system. The NESC was requested to assess 

the current system, develop new concepts if required, 

and develop cost estimates and specifications for any 

suggested upgrades.

NESC Contribution: The NESC created a team of

experts from NASA Centers and industry to address this 

issue. Initially, a study was performed to gather data on 

the existing IRT-FMS. The team then conducted multiple 

technical interchange meetings on-site with IRT facility 

personnel. From these meetings, a better understanding 

of how the facility is currently used, how the associated 

calibration hardware is used, and clearer understanding 

of requirements were developed.

Result: The NESC team developed multiple configurations that would result in satisfaction of the requirements. 

These concepts were drafted, and pros and cons of each 

system were discussed with the facility personnel. The 

concept pictured is the recommended system that best 

meets all of the facility requirements. In the near future, 

estimates of various stages of facility upgrades will be 

made to allow the facility to perform improvements as 

funding becomes available.

Icing Research Tunnel Force Measurement System Evaluation

Problem: Atmospheric winds are a major factor that must 

be addressed during launch vehicle design and day-offlight launch operations to maximize flight performance 

and minimize structural loads. Current launch site wind 

databases from balloon measurements are limited in size 

and temporal sampling intervals, leading to uncertainty in 

potential wind changes and vehicle loading.

NESC Contribution: An NESC team began the 

development of an alternate database from 10 years of 

wind measurements made by vertically pointing Doppler 

radar wind profiler systems at KSC. This alternate 

database will provide much higher fidelity in sample size 

and temporal wind change, resulting in more accurate 

quantification of wind effects on vehicle loads and the 

potential for significant improvements in performance 

and reduced risk for future launch vehicles. After the 

NESC team began the development, the Space Launch 

System (SLS) Program decided to continue the work 

to quickly integrate the results into their launch vehicle

development effort.

Result: Planned for completion in 2013, the database 

will be made available to NASA and commercial launch 

vehicle communities. In addition to the database, the SLS 

Program will pursue the development of algorithms to 

process Doppler radar measurements to be used for dayof-flight analyses and launch decisions. These algorithms 

would provide much more timely characterization of winds 

as compared to balloon measurements (15 minutes vs. 2 

hours), resulting in more accurate determination of ascent 

loading, improved launch opportunities, and reduced risk.

Doppler Radar Wind Profiler for Determination of Launch Winds

Wind shear between 500-1000 feet, viewable by exhaust plume from 

STS-119 launch on March 15, 2009. 

Tunnel floor

Test article

Balance 

adaptor

Turntable

Cruciform

Monolithic 

balance

IRT test

section

Lower 

chamber

NESC recommended concept for GRC IRT FMS includes a new 

monolithic balance and balance adaptor and modifications to the 

existing turntable and cruciform.

General

28
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: Refined knockdown factors may enable 

significant weight savings in launch vehicles and help 

mitigate their development and performance risks. The 

NESC Shell Buckling Knockdown Factor (SBKF) Project 

was established in March 2007 to develop and validate 

new analysis-based shell buckling design factors for 

future metallic and composite launch vehicle structures.

NESC Contribution: The NESC has supported a 

significant portion of the SBKF Project, including 

funding for the design and fabrication of large-scale test 

capabilities, fabrication and testing of five large-scale 

test articles, programmatic and technical support, peer 

reviews, and advocacy.

Result: In 2011, the SBKF Project made significant 

progress in several key work areas, including high-fidelity 

analyses and testing of metallic and composite structures, 

benchmarking of commercial codes for nonlinear 

structural analysis, developing the first generation 

analysis-based shell buckling design factors, and a draft 

of the new design guidelines for buckling-critical launch 

vehicle shell structures. Some of the highlights include 

successful fabrication and testing of the first of two 

27.5-foot-diameter orthogrid-stiffened barrels at MSFC in 

March 2011. The objective of these tests is to prove that 

the design data and methods that are being developed 

and validated for smaller scale barrels can be scaled to 

larger-diameter barrels such as those that would exist in 

the next generation of launch vehicles. The test articles 

were fabricated from excess space shuttle external tank 

barrel panels and were welded together using MSFC’s 

new vertical weld tool. The test articles are instrumented 

with over 800 individual strain and displacement sensors. 

Low-speed and high-speed video image correlation 

systems were used to obtain full-field displacement and 

strain measurements during the pre-buckling, transientbuckling, and post-buckling test phases. The high-fidelity 

analysis predictions of the first full-scale test continue to 

correlate well. A second 27.5-foot-diameter test article 

is planned for testing in fiscal year (FY)12 and will be 

subjected to different loading conditions from the first test 

and will provide additional data for model validation. Once 

these analyses are validated at the subscale and full-scale 

levels, they will become the basis of refined analysisbased design factors.

In addition to the SBKF Project development efforts on 

aluminum-lithium (Al-Li) stiffened cylinders, this activity 

is pursuing a parallel effort for fiber-reinforced composite 

cylinders. The central goal of this composites effort is to 

examine how the refined buckling recommendations can 

be extended to composite cylinders. Experimental and 

analytical studies are underway to meet this goal. Industry 

partners are providing 8-foot-diameter and 13-footdiameter composite cylinders for buckling tests. The 

8-foot-diameter cylinder has an out-of-autoclave sandwich 

composite construction, and the 13-foot-diameter cylinder 

has an autoclave-cured, fluted core composite (FCC) 

construction with lightweight longitudinal joints. SBKF has 

completed a series of tests on the FCC subcomponents 

with and without low-speed impact damage and has 

also helped develop and validate a novel lightweight joint 

design. A 13-foot-diameter barrel has been successfully 

manufactured and was shipped to LaRC in August 2011. 

It is scheduled for testing in FY12. Preliminary screening 

tests were completed for an alternate thick-plate Al-Li 

alloy 2050 for heavy-lift core stage components, and 

the activity spun off into a small business innovation 

research effort. Preliminary results indicate that the 2050 

material may provide significant weight savings in highly 

loaded, buckling-critical structures where tall stiffener 

cross-sections are desirable. Currently, Al-Li alloy 2195 is 

limited to a 2.0-inch thick plate. In contrast, 2050 can be 

made in a plate up to 6 inches thick and enables higher 

structural efficiency by using taller integrally machined 

stiffener sections. The SBKF Project sponsored the 

Third Annual Users Workshop with industry and NASA 

engineers and discipline experts in August 2011. Of 

the 40 plus attendees, 25 were from industry including 

representatives from Alliant Techsystems Inc., The Boeing 

Company, Lockheed Martin Corp., Northrop-Grumman 

Corp., United Launch Alliance, Limited Liability Corp., 

and Dynetics Inc. The workshop was a great success, 

highlighted by open discussion, feedback, and interest 

from industry attendees. 

Launch Vehicle Shell Buckling Knockdown Factors Testing

A section of a space shuttle external tank covered in photogrammetry 

targets shown mounted in the shell buckling test fixture.

General

29
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: Grease contamination identified in bearings installed in 145 reaction 

wheel assemblies (RWAs) presented 

risks to flight for several NASA programs, 

including the Landsat Data Continuity 

Mission, Nuclear Spectroscopic Telescope Array, Tracking and Data Relay 

Satellite (TDRS) Spacecraft (K and L), 

and Soil Moisture Active Passive Mission.

NESC Contribution: In response to 

this issue, an NESC team was formed to 

identify affected programs and to evaluate 

root cause and the risks associated 

with the various actions considered at 

that time, including fly-as-is, clean and 

relubricate, and procuring bearings anew. 

The team was composed of experts from 

the NESC Mechanical Systems and 

Guidance, Navigation, and Control (GNC) 

Technical Discipline Teams representing 

the areas of bearings, lubrication, GNC, 

and mechanical systems. Working closely 

with the RWA and grease manufacturers, 

the NESC team was granted access 

to the respective facilities, proprietary 

drawings, processes, and procedures 

facilitating an expeditious review and 

risk assessment of the proposals under 

consideration.

Result: Overall, the team affirmed the 

root cause of the grease contamination 

and concluded that the cleaning and 

relubrication of affected RWA bearings 

presented no greater risk than flying new 

bearings.

Flight simulations in the American aerospace industry 

and NASA, in general, utilize independently developed 

software frameworks tailored for a single facility, and 

are thus incompatible with other facilities, even within 

the same NASA Center. Sharing of simulation models 

frequently requires extensive manual effort re-writing 

source code to “re-host” a model in a new environment. 

A multi-Center team was formed to assess a new method 

to make models more easily interchangeable. The team 

examined a draft American Institute of Aeronautics 

and Astronautics (AIAA) standard (now published as 

American National Standards Institute/AIAA-S-119-2011) 

that addresses this problem by using a specialized 

extensible markup language (XML) grammar to encode 

high-fidelity flight simulation models. Each participating 

Center developed the tools to automatically import and 

validate these XML models in their simulation framework 

and provided feedback to improve the standard and 

application in NASA facilities. Each Center was successful 

in importing and re-hosting an example aerodynamic 

model of a lifting-body re-entry vehicle into their real-time 

simulation framework. With these simulation exchange 

tools in place, each participating Center can re-host new 

models in minutes instead of months. Several suggestions 

for improvements in the standard were forwarded to the 

Modeling and Simulation Technical Committee of the 

AIAA and were incorporated in the released standard. 

Based on the NESC recommendation, NASA has adopted 

AIAA-S-119 as an endorsed NASA standard.

TDRS K/L satellites contain RWAs identified in this study.

Flight Simulation Software Model Exchange Standard

Reaction Wheel Assembly Lubricant Contamination Study

Vehicle used to test flight simulation model exchange standard.

General

30
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: NASA uses aerobraking 

to reduce the fuel required to 

deliver a spacecraft into its desired 

final orbit around a target planet or 

moon with a significant atmosphere.

While aerobraking reduces the 

propellant required to reach

the final orbit, this reduction comes 

at the expense of orbital insertion 

time (typically 3 to 6 months) and 

continuous deep space network 

(DSN) coverage, and requires a 

large ground staff to continuously 

monitor the spacecraft during 

the aerobraking maneuver. The 

requirement for ground monitoring 

and trajectory correction introduces 

the potential for error due to time

lag between Earth and the 

spacecraft, and the possibility that 

the critical data entry could occur 

during nontraditional working hours. 

This potential for error increases 

during the final orbital insertion 

phases, as the requirements and 

frequency for trajectory corrections 

increase and the ability to correct 

prior errors decreases. Studies 

indicate much of the daily operations 

during aerobraking could be moved 

to the spacecraft (autonomous 

aerobraking), thus reducing risk and 

saving much of the cost required for 

the aerobraking phase.

NESC Contribution: An NESC team is developing the 

capability to move the ground-based daily aerobraking 

maneuver processes onboard the spacecraft. These 

onboard processes include an ephemeris (orbital position) 

estimator, atmospheric density modeling, thermal 

modeling of the critical spacecraft elements, and maneuver 

strategy logic to keep the spacecraft safe and provide 

for the proper final orbital insertion. This suite of models 

and algorithms is known as the autonomous aerobraking 

development software (AADS). Mars, Venus, and Titan are 

the most likely targets that would use aerobraking, and 

each has significantly different aerobraking challenges.

Result: Preliminary testing of the initial AADS at Mars and 

Venus with ground-based “truth” simulations indicates that 

AADS could allow for autonomous control of a spacecraft 

for approximately 7 days with sufficient margin to account 

for uplink and other delays before a ground-based update 

would be necessary. This 7-day update cycle meets the 

goal set for AADS and could greatly reduce the DSN 

and ground-staffing requirements. Ultimately, AADS will 

be targeted for inclusion on a future spacecraft mission 

for flight evaluation in a “shadow mode,” where onboard 

autonomous aerobraking commands would be compared 

to the actual aerobraking commands implemented 

by the ground operations team. Once shadow-mode 

flight validation is successfully completed, autonomous 

aerobraking could be used as the prime aerobraking 

operations strategy for future missions.

The Mars Reconnaissance Orbiter dips into the thin Martian atmosphere to adjust its orbit in 

this artist’s concept illustration.

Development of an Autonomous Aerobraking Capability

NASA Continues Effort to Expand Data Mining and Trending

The NESC is leading an Agency-level Data Mining and 

Trending Working Group (DMTWG) whose purpose is to 

assist in the formulation and implementation of capability 

to strengthen trending of technical data in NASA 

programs and projects and to ensure appropriate visibility 

of data mining and trending. Through workshops, monthly 

meetings, training, and supporting algorithm development, 

the NESC has developed working relationships with 

data mining and statistical experts within NASA, other 

government agencies, academia, and industry. The 

DMTWG is assisting NASA organizations by providing 

data mining expertise to relevant NESC assessments. 

The team also sponsors interns and student faculty

teams to assist in data mining activities. This working 

group provides a forum to enhance data mining and 

trending communications across the Agency by sharing 

ideas, methods, technologies, processes, tools, and 

lessons learned.

General

31
2011 NESC TECHNICAL UPDATE

Technical Highligh ts

Problem: Over the last several decades, NASA engineers 

have established a number of techniques, methods, and 

approaches for designing, implementing, and testing 

fault management (FM) systems for spacecraft, launch 

vehicles, aeronautical vehicles, and ground systems. One 

can define FM to include fault tolerance, fault mitigation, 

and fault protection. FM is a nontraditional discipline, as 

compared to the structures discipline, most often affiliated 

with systems engineering and/or software engineering. 

Generically speaking, FM encompasses functions 

that enable an operational system to prevent or detect, 

isolate, diagnose, and respond to anomalous and failed 

conditions interfering with nominal mission operations. FM 

is beginning to be recognized as an engineering discipline 

that addresses the occurrence of faults in a given system. 

It serves to provide a reliable means for reducing the 

impact of faults through cooperative design between 

system-level and subsystem-level elements.

The performance of NASA’s FM systems has generally 

been successful. However, in several cases, development 

of these systems has adversely stressed NASA’s 

programmatic and engineering resources. In particular, 

flight projects have suffered from unexpected cost

growth and schedule slips during final FM system 

integration and test. It has become apparent that reliable 

and affordable FM systems are not constrained by 

technology, but rather by a lack of systematic engineering 

and programmatic discipline.

NESC Contribution: The NESC recognizes that FM is 

a key driver to increase safety, reliability, availability, and 

performance in NASA’s systems, and should have the 

rigor of other safety critical processes. To provide some 

of that missing rigor, the NESC, in collaboration with JPL, 

has developed a NASA Fault Management Handbook, 

NASA-HDBK-1002, to provide overarching conceptual 

engineering guidelines and recommended best practices.

Result: The handbook has been entered into the formal 

NASA Standards Program Office system, and it recently 

completed a comprehensive Agency-level review and 

comment cycle. FM is overdue to move from an art to an 

engineering discipline characterized by a known, agreed 

upon, and consistent methodology to structure FM and its 

relationship to other branches of engineering and design. 

The insights and concepts captured in this handbook 

provide a basis for moving the field toward a formal and 

consistent methodology. Application on future programs 

may help to avoid program cost overruns, schedule slips, 

and in-flight failures traceable to a lack of established 

approaches as well as disciplined and systematic FM 

development techniques. The NESC will continue to work 

on maturing the handbook with plans for disseminating it 

to Agency users in 2012. 

Development of a Fault Management Practitioner’s Handbook

FM systems play 

a prominent role 

within NASA’s 

aeronautics, 

human, and 

robotic spaceflight 

missions.

General

32
The composite crew module underwent destructive testing in LaRC’s Combined Loads Testing Facility 2011 NESC TECHNICAL UPDATE

Innovative

Techniques

Innovative approaches and techniques developed from NESC assessments
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

The NESC Composite Crew Module (CCM) Project was a rapid design and development project conducted 

from 2007 to 2010. The final product was a full-scale CCM designed, manufactured, and tested, ultimately 

to destruction, by a NASA and industry team that achieved the early design mass predictions and the pretest analytical performance predictions. The 3-year project incorporated a number of technology spin-offs 

that are directly relevant to future composite structures. There are six engineering reports describing aspects 

of CCM as well as conclusions from the overall effort. These reports include Design, Analysis, Materials 

and Processes, Manufacturing, Test, and Nondestructive Evaluation. Each of these reports provides detailed 

discussions of the unique technology applications and are available on nesc.nasa.gov.

Co-cured 

3D woven 

joints 

CCM Material and Processes Report

NASA/TM-2011-217189

CCM Analysis Report

NASA/TM-2011-217188

CCM Nondestructive

Evaluation Report

NASA/TM-2011-217191

Fiber optic strain measurement system 

Infrared 

thermography 

inspection

Application 

of hypersizer 

software 

code

CCM Test Report

NASA/TM-2011-217190

CCM Manufacturing Report

NASA/TM-2011-217187

Out of autoclave, Kapton heater localize material curing 

and repair system Damage 

tolerance 

assessment 

34
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

In 2010 the NESC performed an assessment 

of the destabilizing impact of the former Orion 

Crew Exploration Vehicle (CEV) service module 

propellant slosh dynamics on the Ares-I crew 

launch vehicle flight control system (FCS). 

Concerns had been raised about the Ares-I 

boost phase stability and control because the 

standard frequency domain synthesis methods 

could not yield an FCS design with sufficient gain 

and phase stability robustness margins which 

also met the performance requirements. The 

assessment prompted a follow-up investigation 

into how NASA and industry have historically 

addressed regions of instability or violations of 

margin requirements. When stability robustness 

margin requirements cannot be satisfied using 

frequency-domain methods, alternative methods 

are then needed to ensure that deficient stability 

margins do not present a high risk of a flight 

control issue (e.g., loss of control) during the 

mission. A large body of experience has been 

accumulated at NASA regarding successfully 

flying through temporary periods of linear 

instability as the flight environment and vehicle 

dynamics undergo rapid changes. For example, 

the space shuttle had ascent and entry guidance, 

navigation, and control (GNC) stability verification 

issues. The Space Shuttle GNC Team identified 

four possible techniques for accomplishing entry 

FCS certification with deficient stability margins:

• Engineering Judgment: Exploit previous experience with a specific situation to declare that no 

additional analysis is required if a stability margin fails the requirement by only a small amount.

• Evaluation of Uncertainties: Conduct a “sanity 

check” to re-assess whether the uncertainties 

input into the analysis are realistic. In certain 

cases, the effects of correlated variables can 

be taken into account to reduce the level of uncertainties used in the analysis.

• Checking the Time to Double Amplitude:

Determine if the vehicle will fly through the 

region of concern before the oscillations reach 

unacceptable amplitudes, in which case a lower 

margin may be acceptable.

• Use of Time-Domain Simulations: Exploit the highfidelity non-linear time-domain models to prove that 

the vehicle exhibits acceptable behavior, even with programmed test inputs or other inputs to excite oscillations. Additionally, the loop gains and/or time lags can 

be increased in the simulation to evaluate the actual stability margins remaining.

Similar insights and lessons were obtained by the NESC’s 

slosh assessment GNC team in consultation with industry. The NESC found that historically some launch vehicles have been successfully flown by industry with the 

known threat of slosh instabilities. The NESC learned that 

the Atlas-II launch vehicle was safely flown with linearly

unstable (as viewed from a purely linear frequency-domain 

perspective) slosh modes.

The primary lesson learned during this assessment 

was that an FCS designer should not rely exclusively on

frequency-domain approaches to verify/certify stable 

flight. Designers should use all the tools and techniques 

at their disposal, including the four previously identified. 

The use and application of the frequency-domain synthesis and analysis tools must be balanced with time-domain 

performance simulation tools and possibly other considerations. The same techniques mentioned above apply 

generally to the analysis and evaluation of any potential

instability: propellant slosh modes, flexible structure 

modes, or aerodynamic instabilities encountered by vehicles flying through rapidly changing aerodynamic regimes.

For more information, contact Cornelius Dennehy

(cornelius.j.dennehy@nasa.gov) 

Flying Through Periods of Instability

GNC lessons learned on instabilities can be applied to future NASA projects, such 

as the space launch system.

35
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

A new photogrammetry technique has been developed 

that allows accurate six degrees of freedom (6-DOF) 

orientation measurements to be made of large, moving 

rigid bodies.

This technique can provide data of vehicle dynamics or 

motions with accuracy equal to or better than inertial 

measurement units and has been used on multiple NESCsponsored projects. Maximum flexibility is provided in 

choosing the number of cameras, the types of lenses, and 

the placement of those cameras in accessible locations 

for a flight experiment or ground test facility without 

overlapping camera view constraints.

The technique was developed to measure the separation 

of a full-scale Orion crew module (CM) from its protective 

forward fairing during NASA’s Max Launch Abort System 

(MLAS) flight test. Photogrammetric analysis of the 6-DOF 

separation was a critical measurement for comparison with 

inertial measurement units. Conventional photogrammetry 

techniques require low-distortion lenses and overlapping 

camera views of the object of interest and could not be 

used on the MLAS test due to space constraints. Thus 

the new algorithm was developed, which used fish-eye 

lenses and nonoverlapping views. Later, the technique 

was used to accurately measure the position and attitude 

of a full-scale Orion CM during water entry testing at 

various entry angles and velocities. Again, multiple highspeed cameras were used with views that did not fully 

overlap. The algorithm was extended to accommodate 

different camera lenses, calibration methods, and more 

automated processing. Over 60 drops were recorded and 

processed.

Photogrammetric targets are first applied to the body and 

surveyed. Given that each camera observes a separate 

subset of the photogrammetric targets on the object of 

interest, if all those targets are constrained to the same 

rigid body, then a representative set of equations can 

be developed. The solution to the equations is the one 

unique 6-DOF orientation of the rigid object that results 

in the target patterns observed in all the cameras. 

Modern camera calibration techniques were employed by 

capturing and analyzing numerous images of objects with 

well-known structure, such as arrays of regularly spaced 

dots or squares. Finally, a robust target-tracking algorithm 

was implemented, which could follow targets from frame 

to frame, even in the midst of significant flying debris or 

water droplets. All these technologies were combined into 

a MATLAB/LabVIEW platform, which could be used at the 

test site immediately after an experiment. Measurement 

accuracy of the CM/fairing relative positions was to within 

0.50 inch even after 16 feet of separation. Displacements 

with millimeter accuracy and attitude within hundredths of 

a degree were obtained for the water entry tests.

For more information, contact Kurt Severance

(kurt.severance@nasa.gov)

New Photogrammetry Technique is Accurate and Adaptable

High-speed photogrammetry was used to precisely track a boilerplate Orion crew module (CM) in full-scale 

water drop tests. Vector overlays, based upon computer-aided design and photogrammetry measurements, 

were added to visualize the orientation, trajectory, maximum plunge depth, and wetted area of the CM.

36
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

Frequently, as part of a Structural Validation Test Program, 

the addition of test components as well as instrumentation 

can lead to some degree of uncertainty regarding the 

known position of the center of gravity (CG) of a test 

article. To assist the LS-DYNA model validation for the 

Orion boilerplate crew module (CM), an independent 

method of determining the CM CG was investigated. 

The CG, which serves as the origin for all six degrees 

of freedom measurements, is critical for test/model 

parameter correlation. 

To support the task, a photogrammetric method was 

devised to measure the position of the CM at different 

hang angles using an asymmetric 2-point lifting strap

(Figure 1). Two lifting straps were constructed to provide 

hang angles of 20 and 30 degrees, respectively. The 

combination of the two straps provided eight unique 

positions from which the CM could be suspended. A key 

component of the technique was a plumb line suspended 

from the same lifting hook. The concept theorized the 

vector representing the plumb line, if extended, would 

pass through the CM and the CG would lie somewhere 

along that line. The plumb line visibility was maintained 

by attaching retro-reflective spheres along its length. By 

photogrammetrically measuring the plumb line position at 

the various hand angles, the plumb lines would intersect at 

a common point representing the CG. At each of the eight 

positions, the CM/plumb line were imaged and processed 

to find the position of the CM and the plumb line in a 

three-dimensional space. The resulting measurement 

data were consolidated to provide an array of line vectors 

representing the theoretical plumb line that intersect at 

the CG of the module (Figure 2). To combat the effects 

of wind and motion on the plumb line, a redundant line 

not attached to the test article or crane was included to 

correct the potential error in the primary plumb line.

When processing the data, it must be considered the 

plumb line vectors are unlikely to actually intersect. To 

determine the best-fit CG, an algorithm that approximates 

the center by finding the point that minimizes the sum of 

the squared distances between that point and each of the 

plumb lines was developed. The results from this test have 

shown good correlation to the original computer-aided 

design-estimated CG and that verified independently with 

classic fixture methods. The results, as determined by this 

method, converged to sphere with radius less than 0.667 

inch in all axis and are shown as an offset from the origin 

of 0.367 inch (Figure 3).

This method could eliminate the costly and complex 

equipment required for CG determination via traditional 

methods. The technique lends itself very well to large 

bodies, oddly shaped bodies, and fragile flight hardware, 

and it can be executed much more quickly than traditional 

measurement techniques.

For more information, contact Thomas Jones

(thomas.w.jones@nasa.gov) 

Center of Gravity Determination Using Photogrammetry

Figure 1. CM in CG test configuration 

with plumb line(s).

Figure 2. Consolidated data including vectors 

representing eight plumb lines.

Figure 3. Intersecting plumb lines at 

CG. Inclusive sphere radius 0.667 

inches. Center offset from origin 0.367 

inches.

37
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

When engineers need to verify compliance with a design 

requirement using Monte Carlo simulation, they need 

to know how many trials to run and if the requirement 

was met. A set of plan calculators is now available to 

help. The requirement will outline the design conditions, 

the minimum reliability demanded, and the maximum 

probability of accepting a noncompliant design resulting 

from statistical error. The calculators will do the rest. 

The plan calculators are implemented as (beta-test) 

Excel spreadsheets. The calculators were developed 

from the literature on acceptance sampling—a statistical 

quality control technique originally intended for sampling 

inspection in production/supply-chain environments. The 

plans are appropriate for this original purpose, as well as 

for Monte Carlo applications in design.

For more information, contact

Dr. K. Preston White (kpwhite@virginia.edu) or 

Kenneth Johnson (kenneth.l.johnson@nasa.gov) 

Composite pressure vessels (CPVs) 

are used widely in spacecraft 

and other applications to obtain 

significant weight savings over 

metal pressure vessels. However, 

CPV variability has continued to 

be relatively high even though 

significant effort has been placed 

on ensuring manufacturing consistency. Additionally, there are 

concerns that liner flaws may go 

undetected, causing failure after 

being pressure cycled in service. 

Most manufacturers currently use 

fluorescent dye penetrant for liner 

flaw detection and borescopes for 

interior visual inspections. However, 

these methods are subject to human 

error and are not as quantitative 

as desired, making additional 

development of nondestructive 

testing methods desirable.

While the NASA Nondestructive 

Working Group started development of internal 

profilometers for CPV evaluation, the NESC Composite 

Pressure Vessel Working Group soon joined as a 

partner to gain analytical capabilities necessary to 

evaluate the mechanical response of CPVs. The WSTF 

has managed the project and handled testing, while the 

scanning hardware development was contracted to Laser 

Techniques Company, Redmond, Washington. A scanning 

station was first developed with a rotating interior sensor 

probe that accurately mapped and measured the interior 

cylindrical profile. The scanning station was later modified 

to also provide external profilometry plus eddy current 

(EC) scanning capabilities.

To perform external profilometry and EC scanning, the 

rotating interior sensor probe is easily removed and 

replaced with offset external sensors and a rotational 

stage spins the CPV (as seen in photo, left). An articulated 

probe and delivery system was also developed to allow 

CPVs with ellipsoid ends to be scanned from port to 

port, as developed first for the Orion service module 

CPVs (as seen in photo, right) and then the International 

Space Station (ISS) nitrogen oxygen recharge system 

(NORS) CPVs. System radial accuracy varies between 

approximately +/- 0.001 to 0.002 inch, depending on the 

port size and other restrictions. This allows pits, bulges, 

distortion, and the amplitude and periodicity of anomalies 

to be evaluated and then imaged with “laser vision.” The EC 

system easily detects exterior cracks and defects ~0.001-

inch deep on the surface of aluminum liners and sensors 

have been developed for evaluation of internal cracks and 

crack detection through the composite material. The flaw 

detection through the composite is greatly degraded, 

but sensitivity is to be quantified for various applications 

(involving JPL and LaRC). The NESC will also supply liners 

with fatigue cracks to help quantify the flaw detection 

capability.

The system has been used for CPV applications at WSTF 

and at CPV supplier facilities. It was used at a supplier 

facility to incrementally evaluate mechanical response 

as the liners were wrapped and then autofrettaged in 

support of ISS stress rupture testing. The system was

also used in the NESC study that characterized the 

response of aluminum lined T1000 and IM7 carbon 

vessels to autofrettage and a new NORS system has 

been delivered to characterize their CPVs as a part of 

developmental testing.

For more information, contact Regor Saulsberry

(regor.l.saulsberry@nasa.gov)

Development of a Composite Pressure Vessel Laser Profilometry and Eddy Current Scanning 

System to Meet Manufacturing and Analytical Needs

Statistical Sampling Plan Calculators

(Left photo) WSTF personnel, Paul Spencer, left, and Charles Nichols, right, configure a desktop 

system to do EC scanning of a liner defect standard. (Right photo) A 48-inch Orion service module 

CPV simulator in the tall delivery stage.

38
2011 NESC TECHNICAL UPDATE

Innova tive Techniques

A tool developed by two members of the NESC team 

assessing improved International Space Station (ISS) 

micrometeoroid and orbital debris (MMOD) damage 

shielding designs will provide more accurate prediction 

of damage produced by MMOD impacts. Older equations 

used for MMOD damage prediction are based on limited 

data and are applicable only to a narrow range of shield 

materials and configurations. A new damage prediction 

tool was developed that more accurately predicts the hole 

size and crack length caused by a hypervelocity impact 

(HVI) on a pressurized spacecraft cabin or module. This 

tool, called the W-S hole/crack prediction model, was 

designed to be used within the application that calculates 

the risk of an MMOD-caused catastrophic failure. Like 

earlier models, the W-S model will provide results based 

on a given particle size, impact obliquity, and velocity. 

However, the new model also uses parameters associated 

with the shield configuration as independent variables. 

Typical MMOD shielding includes an outer shield called a 

bumper, an inner shield called the rear wall, and a space 

between the two called the standoff. There may also be 

intermediate shields or thermal insulation blankets between 

the bumper and the rear wall. The shield parameters that 

are included in the W-S model are those related to the 

material and geometry of the rear wall and bumper, the 

standoff distance from the bumper to the rear wall, and 

the mass and placement of any intermediate bumpers. 

The result is a generic damage predictor that can be 

universally applied to different shield configurations.

W-S model damage predictions compared to the results 

using older models show that while the newer predictions 

tend to predict larger hole sizes than previous models, HVI 

test data correlate more closely to the W-S predictions. The 

W-S equation is now being used for the ISS in calculating 

the risk of catastrophic MMOD damage to ISS modules, 

but in the future can be applied to other spacecraft with 

different MMOD shield configurations. 

For more information, contact Dr. Joel Williamsen

(jwilliam@ida.org) or Dr. William Schonberg (wschon@mst.edu)

An analytical technique developed during 

the Apollo Program for predicting the effect 

of a drogue parachute on the vehicle’s 

oscillatory motion was rediscovered and 

applied during an NESC assessment 

to the Orion crew module (CM) drogue 

system with improved prediction results 

over current methods. One of the prime 

functions of a drogue parachute is to 

stabilize and damp vehicle oscillations 

to provide a stable platform for main 

parachute deployment. When the drogue 

parachutes were deployed during the Pad 

Abort-1 (PA-1) flight, they produced more 

damping than was predicted by twobody 6 degrees of freedom simulations. 

To resolve this difference, the Apollo-era 

technique was resurrected and shown to 

accurately predict the full-scale motion.

During PA-1, the CM initial orientation at 

drogue deploy had large oscillation angles 

and rates, as expected. The combined 

effect of the vehicle and drogue damping 

caused the system to damp much faster than preflight 

simulations had predicted. This faster flight damping was 

also predicted by wind tunnel tests on scaled models 

in the LaRC Vertical Spin Tunnel (VST). To explain this 

anomaly, the legacy tools and techniques used to analyze 

Apollo drogue flight test motion were resurrected. The 

legacy hypothesis is that the drogues will align with the 

total velocity vector at the attach point. This assumption 

was empirically verified by examining both VST and PA-1 

measured relative motion of the drogue with respect to 

the CM. The legacy tool supports single-body simulations 

by modeling an effective drogue static and dynamic 

moment. Using these models, the single-body simulator 

accurately predicted the PA-1 oscillatory motion. 

Additional VST testing is scheduled 

to acquire the necessary data for the 

legacy method to further validate its 

applicability and to refine Orion drogue 

parachute performance predictions. 

The basis of the Apollo legacy damping 

model is the hypothesis that the drogue 

parachute aligns with the resultant 

velocity of the attach point on the CM. 

This resultant velocity is the sum of the 

free-stream velocity plus the velocity 

induced by the angular rates of the 

system about its center of gravity 

(CG). The parachute damping results 

from a hysteresis in the moment arm 

of the parachute as the CM oscillates 

over a cycle. Simple equations for the 

equivalent static and dynamic moments 

about the system CG due to the drogue 

parachutes were recently derived. 

These equations provide a powerful 

preliminary design and analysis tool for 

use with drogue parachutes. It is noted 

that the Apollo legacy model is applicable only to smallersized parachutes such as drogue parachutes. The 

large parachute mass and associated air mass for main 

parachutes prevent the lateral motions required to align 

with the attach point velocity.

As a result of the accurate prediction of the PA-1 drogue 

motion, the Apollo legacy methodology has been adopted 

by the Orion Multi-Purpose Crew Vehicle Program for their 

drogue parachute performance predictions. This legacy 

tool plus recent improvements is now available to the 

NASA community. 

For more information, contact Dr. David Schuster

(david.m.schuster@nasa.gov)

Apollo Era Drogue Damping Estimation Technique

Improved Micrometeoroid and Orbital Debris Damage Prediction

Drogue resultant force acts in line with 

the free-stream velocity (red vector).

39
2011 NESC TECHNICAL UPDATE

24: ARC

employees who

supported NESC

assessments. 

The A-3 test stand under construction at SSC.

Center

Focus
2011 NESC TECHNICAL UPDATE

Center Focus

Working to Preserve Heritage Thermal Protection

System Materials

Dr. Ethiraj Venkatapathy, Chief Technologist for the Entry 

Systems and Technology Division at ARC, brought his 

concerns to the NESC about the threat to future NASA 

missions posed by uncertainties in the continued 

availability of heritage carbon phenolic thermal protection 

system (TPS) material. The NESC formed a team that 

included NASA Technical Fellows to assess the problem. 

The team provided a recommendation to the Office of 

the Chief Engineer urging the Agency to immediately 

fund carbonizing all remaining heritage rayon before 

the carbonizing facility was shut down permanently; 

thereby ensuring critical mission needs are met in

the future. By being receptive to issues such as 

sustainable TPS material availability and bringing those 

issues to the attention of Agency decision makers, the 

NESC played a vital role in maintaining a key capability. 

“This will enable NASA to conduct missions such as Mars 

Sample Return, Venus Landers, and Saturn Probes, and 

use the knowledge gained on those missions to address 

origin of life questions, the Venus-Earth-Mars connection, 

and the evolution of solar system,” said Dr. Venkatapathy.

Developing Wireless Sensor Networks for Spacecraft

Rick Alena, computer engineer, led an NESC team that 

developed new wireless sensor network technology suitable for structural health monitoring of composites used 

for aerospace vehicle structures. Using the latest ZigBee system-on-a-chip (SoC) technology, the development team interfaced piezoelectric strain sensors and 

micro-electric mechanical-based accelerometers to prototype circuits, updating the firmware to incorporate time 

stamps, raw data values, and engineering data values into 

the wireless data stream. Concepts for packaging the SoC 

in micro-miniature assemblies complete with multiple sensors for payload shroud structural monitoring were developed, meeting basic requirements for developmental and 

flight instrumentation. This technology was presented to 

the Ares Data Bus Study Team at MSFC for use onboard 

future heavy lift launch vehicles. In addition, a concept 

for payload shroud monitoring in flight was presented to 

the NESC Chief Scientist. “The NESC-sponsored work 

on wireless sensor networks has generated a number of 

innovative approaches for new health-monitoring technology for space exploration vehicles, adding new capability 

for strain, temperature, and acceleration measurements 

during wind tunnel and flight test,” Mr. Alena stated.

Ames Research Center (ARC) has

a diverse set of capabilities and 

expertise and, thanks to involvement

in the NESC's assessments and 

Technical Discipline Teams, this 

expertise is supporting a wide variety 

of Agency programs and activities. 

Some examples from this past year 

include tapping into ARC expertise in information 

technology to support the Department of 

Transportation National Highway Traffic Safety 

Administration Toyota Unintended Acceleration 

Investigation. Various throttle control system 

software modules were modeled and analyzed 

using tools that included ARC-developed 

software diagnostic programs. For aerodynamics, 

ARC has technical expertise and unique 

infrastructure, such as multiple wind tunnels and 

a supercomputer running state-of-theart computational fluid dynamics (CFD) 

simulations/analyses. In this area, ARC 

has supported at least two significant 

NESC assessments this past year. In 

the beginning of the year, a special test 

was completed in the 11-foot Transonic 

Unitary Wind Tunnel that investigated 

rocket plume interaction from the Orion launch 

abort system. This test used hot high-pressure 

helium gas to simulate the rocket plumes while 

being tested at transonic speeds in the tunnel test 

section. In another assessment, ARC personnel 

are developing and conducting a wind tunnel test 

to verify and validate the CFD predictions related 

to wake flow with regards to characteristics and 

loads required in designing the Capsule Parachute 

Assembly System.

Ames Research Center

Nans Kunz

C

ARC

employees

supporting

NESC

assessments 

24:

Rick Alena conducts an experiment on a new wireless sensor network prototype.

Matthew Gasch (left), Ethiraj Venkatapathy (middle), and Jay Feldman (right) analyze the manufacturing process requirements for 

chop molded carbon phenolic heatshield material.

NESC Chief 

Engineer at 

ARC

41
2011 NESC TECHNICAL UPDATE

Center Focus

ASMTG Supports CCM Testing

Dr. Lance Richards, Allen Parker, Anthony Plazza, and 

Dr. Hon “Patrick” Chan of the DFRC ASMTG supported 

structural testing of the CCM. The group developed an 

innovative technique that enabled fiber optic strain sensors to be visualized onto a three-dimensional profile of a 

test article, namely the CCM door and hatches. It allowed 

the distributed strain measurement to be projected on the 

object’s surface in real time. This technology has helped 

pave the way for new aeronautics research at DFRC and 

continues to aid researchers in monitoring critical areas 

of structures during testing. Dr. Lance Richards, the lead 

of the ASMTG and a member of the NESC Nondestructive Evaluation TDT since 2006, spoke for the group when 

he stated, “Working on the assessment team was an invaluable experience for our fiber optic sensing team both 

technically and personally. The experience provided our 

team a unique opportunity to work with the Agency’s finest on a technically relevant and challenging project. We 

were amazed at the high level of performance, individually and corporately, as well as the technical success the 

project was able to achieve. We are very grateful for the 

opportunity to participate on a project of this magnitude.” 

The DFRC ASMTG also applied this technique extensively 

while working on several projects post-CCM such as testing risk reduction simulated wing structures for DFRC’s 

F-18 as part of NASA’s aeronautics research. The technique has been used to visualize pressure-induced strain 

changes of the composite overwrapped pressure vessels 

at WSTF.

Enhancing and Applying GNC Skills 

Chris Regan, a controls engineer at DFRC, served on a 

1-year detail as an NESC Resident Engineer. He supported 

key NESC assessments and participated in the NESC GNC 

TDT. “The experience I had with the NESC allowed me to 

participate in diverse multi-Center, multidisciplinary teams 

working in fast-paced environments,” Mr. Regan stated. 

Mr. Regan performed trajectory reconstruction and data 

analysis tool development for the NESC’s Crew Module 

Water Landing Modeling Assessment, where an instrumented full-scale Orion boilerplate crew module (CM) was 

dropped at various water entry conditions to provide data 

for anchoring Orion CM structural models. “I hadn’t been 

exposed to the space side of the house prior to working 

with the NESC. Nor had I worked on engineering teams 

with members across the Agency. The contacts within 

the Agency and industry helped me develop new skills 

and expertise that I can apply to future DFRC projects,”

Mr. Regan stated. Mr. Regan also extended his skills by 

conducting software analysis and hardware testing for 

the NESC in support of the Department of Transportation

National Highway Traffic Safety Administration Toyota

Unintended Acceleration Investigation.

Dryden Flight Research Center (DFRC)

engineers supported numerous 

NESC activities that contributed to the 

success of the Agency’s programs and 

projects. DFRC engineers are members 

of most NESC Technical Discipline 

Teams (TDT) and have supported 

numerous TDT activities, such as 

contributing to the development of a Community of 

Practice website for programmable logic devices 

as part of the NESC Avionics TDT. DFRC engineers 

supported the Guidance, Navigation, and 

Control (GNC) TDT and are developing a control 

system short course for NASA engineers that 

focuses on both classical and modern 

methods to meet the needs of NASA. 

The NESC engineers have supported 

the DFRC Independent Review Team 

for the Stratosphere Observatory for 

Infrared Astronomy (SOFIA) Telescope 

liquid nitrogen precooling system and 

procedures. This review ensured both 

the system and procedures were safe and could 

be used to support the SOFIA Program. The DFRC 

Advanced Structures Measurement Technology 

Group (ASMTG) received NESC awards for their 

outstanding contributions to the structural testing 

of the NESC Composite Crew Module (CCM).

Dryden Flight Research Center

Dr. James F.

Stewart

DFRC

employees

supporting

NESC

assessments 

10:

Former NESC Resident Engineer Chris Regan. 

David McBride, DFRC Director (far left), and Dr. James Stewart (far 

right), present the NESC Group Achievement Award to (center, from 

left to right) Dr. Lance Richards, Allen Parker, Anthony Plazza, and 

Dr. Hon “Patrick” Chan of the ASMTG.

NESC Chief 

Engineer at 

DFRC

42
2011 NESC TECHNICAL UPDATE

Center Focus

Readying MSL Instrumentation for Launch

NASA missions often push hardware to extremes, and the 

Mars Science Laboratory (MSL) is no exception. During 

development testing, high-speed vacuum pump bearings failed unexpectedly putting delivery at risk. Despite 

significant efforts, little progress in understanding the 

problem was being made. The NESC Mechanical Systems TDT member, Dr. Christopher DellaCorte, enlisted 

the help of colleague Dr. S. Adam Howard to model the 

rotordynamics of the pump and its bearings providing vital guidance to the development team in resolving bearing 

assembly, bearing preload, lubrication, and rotor balancing issues. The working pumps have passed qualification 

tests and are waiting to launch on the MSL. Dr. Howard 

is leading an effort to bring advanced bearing modeling 

software to other NASA engineers to aid future projects.

Investigation of Orion CM Crew Safety

Dr. Charles Lawrence, a structural dynamicist at GRC, 

has been a member of several NESC teams involved with 

crewed spacecraft safety. His first involvement with the 

NESC was with the Orion CM water versus land landing 

study and later he worked on the Crew Module Water 

Landing Modeling Assessment. “This was an amazing 

experience being exposed to all aspects of vehicle 

landing including design issues, cost and safety, as well 

as having the opportunity to work with experts across 

the Agency including Apollo astronauts and engineers.” 

Dr. Lawrence has also worked with the NESC on 

developing design options and safety standards for crew 

protection, a vibration isolation system for attenuating 

thrust oscillation from the Ares launch 

vehicle, and an assessment of analytical 

tools for predicting Orion CM structural 

response during water landings. “The 

water drop testing we performed under this 

assessment was an amazing opportunity 

to validate our numerical simulations with 

actual water drop test data and then have 

the results used by Orion CM designers for 

an actual spacecraft design.”

Providing Expertise to the NESC Technical

Discipline Teams

Dr. John Thesken of the Applied Structural Mechanics 

Branch contributes expertise in composite structures, 

test, verification, and flight hardware certification as a 

member of the NESC Composite Pressure Vessel (CPV) 

Working Group and the NESC CCM Test and Verification 

Team. His recent NESC work resulted in more accurate 

life predictions for CPV flight hardware flying on the 

Juno probe to Jupiter. For CCM, GRC contributed test 

article design analysis, element testing, and coordinated 

the implementation of acoustic emission and structural 

health monitoring for the full-scale tests. Ties to strong 

discipline networks help translate valuable lessons 

learned to the Orion MPCV Program and other flight 

programs. “Composite structures development requires a 

multidisciplinary team and the resources to build and test; 

I am grateful for the opportunity the NESC has given us to 

achieve these goals.”

The Glenn Research Center (GRC), 

provided a broad spectrum of 

technical expertise in support of NESC 

assessments and the NESC Technical 

Discipline Teams (TDTs). In support 

of the Orion Crew Module (CM) Water 

Landing Modeling Assessment, a 

boilerplate CM was instrumented to 

measure accelerations, pressures, and strains 

during water drop tests. GRC experts used this 

data to validate analytical models predicting

CM/water interactions during impact. GRC 

continues to provide expertise in tribology 

and mechanical components to numerous 

NESC activities including the International 

Space Station (ISS) solar alpha rotary joint, the 

ISS ammonia cooling pump, and is 

currently utilizing the GRC vacuum 

roller rig to investigate wear and debris 

generation in the James Webb Space 

Telescope near infrared spectrograph 

shutter positioning mechanism. GRC 

also conducted a bonded element 

test of the low impact docking system 

in support of the Composite Crew Module 

(CCM) Test and Verification Team. Digital image 

correlation photogrammetry was used to provide 

a more accurate evaluation of design allowables 

and margins, thus guiding analytical and test 

verification approach recommendations for 

the Orion Multi-Purpose Crew Vehicle (MPCV) 

Program.

Dawn C.

Emerson

Glenn Research Center

GRC

employees

supporting

NESC

assessments 

51:

Dr. Charles

Lawrence

NESC Chief 

Engineer at 

GRC 

Adam Howard (left) 

and Chris Dellacorte of 

the GRC Tribology and 

Mechanical Systems 

Branch review the 

roto-dynamics model 

of a MSL 100,000 rpm 

vacuum pump.

From left, Justin 

Littell, ATK Space 

Systems, Chris 

Burke, research 

technician, and 

John Thesken 

examining a 

broken specimen 

of CPV.

43
2011 NESC TECHNICAL UPDATE

Center Focus

The Goddard Space Flight 

Center (GSFC), including the 

Wallops Flight Facility (WFF), 

participated in a wide range of 

NESC activities during 2011 for 

human exploration and space 

operations, as well as robotic 

space and Earth science missions. The NASA Technical Fellows for Avionics; Electrical Power; Guidance, Navigation, and Control; Mechanical 

Systems; and Software are resident at 

GSFC. The NESC obtained expertise from 

around the Agency to perform independent technical assessments and reviews, 

and provided technical support to GSFC 

activities, including the sample analysis at 

Mars instrument, wide range pump for the 

Mars Science Laboratory, near 

infrared spectrometer microshutter mechanism, mid-infrared 

instrument cryocooler disturbance, and sunshield for the 

James Webb Space Telescope, 

reaction wheel assembly lubricant for the Tracking and Data 

Relay Satellite System, crosstrack infrared sounder instrument frame 

for the Joint Polar Satellite System, Hubble Space Telescope Attitude Observer, 

and Taurus II launch pad testing at WFF. 

NESC discipline activities that benefited 

from multiple GSFC projects included 

improvements in fastener design, wireless connections, thermal databases, fault 

management, and pyrovalve reliability.

Automatic Dynamic Analysis of Mechanical Systems 

for Crew Impact Attenuation System

Cory Powell has been a mechanical engineer with the 

GSFC Mechanical Systems Analysis and Simulation 

Branch for over 5 years. Previously, as a GSFC co-op student, Mr. Powell learned the Automatic Dynamic Analysis 

of Mechanical Systems (ADAMS) software because there 

was no one in his branch experienced with this software 

tool. When the NASA Technical Fellow for Mechanical 

Systems determined that ADAMS analysis may be needed 

for the NESC’s Orion seat attenuation and thrust oscillation assessment, Mr. Powell worked closely with a senior 

engineer at the Johns Hopkins University Applied Physics 

Laboratory to become a proficient ADAMS user. Along 

with Mr. Ben Emory and other mechanical engineers in his 

branch, Mr. Powell analyzed various landing conditions for 

this assessment. Mr. Powell stated, “This NESC assessment highlighted the importance of this type of analysis 

and now my branch has four advanced ADAMS users. After the analysis was completed, I was asked to be the assessment vibration test lead. This was a great experience. 

It allowed me to gain leadership experience and create 

contacts across multiple NASA Centers and universities. 

I also visited JSC, LaRC, and the Naval Warfare Center at 

Dahlgren. In my short time at NASA, this project taught 

me more than any other project. I look forward to working 

with the NESC again.”

Test Support to the NESC Study of Reported

Unintended Acceleration in Toyota Vehicles

Michael Bay is a GSFC systems engineering contractor with 

over 30 years of experience with the design, development, 

and operations of human and robotic space missions.

Mr. Bay has contributed to many NESC activities, including 

the Crew Exploration Vehicle Smart Buyer Design Team 

at GSFC’s Integrated Mission Design Center and systems 

engineering and electrical systems volumes for the Design, 

Development, Test, and Evaluation Considerations for Safe 

and Reliable Human-Rated Spacecraft Systems. Recently, 

Mr. Bay participated in the NESC’s technical support to 

the Department of Transportation National Highway Traffic 

Safety Administration Toyota Unintended Acceleration 

Investigation. He worked with the NASA Technical Fellows 

for Avionics and Software to systematically evaluate 

functional failures in various scenarios using test beds at 

GSFC and Toyota test vehicles. Mr. Bay stated, “There 

are many benefits of serving on NESC assessments. 

Challenging assessments provide a unique opportunity to 

work with engineers from different NASA Centers, industry, 

and academia. These new peers become friends and a 

valuable resource for future collaboration. Working among 

team members from other Centers also broadens my 

experience base and allows me to learn new techniques. 

I have learned so much over the last few years, and it has 

been fun and challenging as well.”

Goddard Space Flight Center

Timothy G.

Trenkle

Dr. John H.

Day

Cory Powell of the GSFC Mechanical Systems and Simulation Branch 

conducted ADAMS analysis for the NESC assessment.

Michael Bay examines engine response to accelerator inputs using 

Toyota’s onboard diagnostic port.

GSFC

employees

supporting

NESC

assessments 

74:

NESC Chief 

Engineer at 

GSFC

NESC Chief 

Engineer at 

GSFC

(Acting)

44
2011 NESC TECHNICAL UPDATE

Center Focus

Development of Field Programmable Gate Array

Training for the Agency

Renee Reynolds and Andrea Dye are engineers with the 

GSFC Electrical Engineering Division. They are working 

with the NASA Technical Fellow for Avionics to develop 

training material that would expand the skill set of NASA 

engineers in programming with microcontrollers and field 

programmable gate arrays (FPGAs).

Ms. Dye started at GSFC as a co-op student, and in 2008 

she converted to a full-time engineer with the Electrical 

Systems Branch after earning an electrical engineering 

degree. Her GSFC responsibilities include development of 

electrical ground support equipment for the Global Precipitation Mission, Magnetospheric MultiScale Mission, 

and Astro-H Mission. Ms. Dye stated, “Working with the 

NESC has allowed me to interact with individuals from 

KSC and learn the atmosphere amongst the engineers, 

working on a multi-Center team. It also allows me to work 

with a greater range of people both at GSFC and KSC. The 

opportunity to support the NESC has been rewarding and 

fulfilling. I have high hopes that this endeavor will allow 

greater collaboration between the Centers and will allow 

other engineers to have the opportunity to expand beyond 

their current skill set.”

Ms. Reynolds began her professional career with the 

GSFC Flight Data Systems and Radiation Effects Branch 

in 2001 as an electrical engineer. Since joining NASA, 

she has earned her master’s degree and received many 

awards for her contributions as FPGA designer and/or 

electronics board designer for major flight projects such as 

Swift Burst Alert Telescope, Solar Dynamic Observatory, 

Lunar Reconnaissance Orbiter, and Hubble Space Telescope Servicing Mission 4. Ms. Reynolds stated, “I plan to

leverage from my work developing the Digital Design 

Training Module to provide a quality training product for 

the NESC. As a result of this opportunity with the NESC, I 

am able to work on a multi-Center team and share technical knowledge with engineers from other NASA Centers.”

Avionics for Crew Module Water Landing

Modeling Assessment

Brian Abresch has been an electronics engineer in 

the Wallops Electrical Engineering Branch for more 

than 10 years. He has been a significant contributor to 

multiple NESC projects, where he served as the avionics 

integration and test lead for the Max Launch Abort 

System (MLAS) and the avionics lead for both phases of 

the Crew Module Water Landing Modeling Assessment 

(CMWLMA). The design, build, and integration of the 

avionics hardware for MLAS and CMWLMA were 

completed at the engineering and integration facilities 

at WFF. Mr. Abresch stated, “I have thoroughly enjoyed 

working with the NESC and all NASA Centers to provide 

the Orion Multi-Purpose Crew Vehicle Program with 

critical empirical data and program risk mitigation. The 

NESC has allowed me the opportunity to participate on 

assessments that provided critical data to high profile 

NASA-wide development efforts. This is a departure 

from many of the missions that WFF typically supports, 

which are generally highly specific and localized science 

missions. It was exciting to know that the information 

collected was part of a much larger and broader effort 

to send NASA’s astronauts beyond Low Earth Orbit. The 

results of the MLAS and CMWLMA Projects will serve 

NASA and the private industry for many years to come.”

Renee Reynolds (center) and Andrea Dye (right), work on a FPGA 

trainer board for the NESC FPGA Development Training Course with 

Oscar Gonzalez, NASA Technical Fellow for Avionics (far left) and 

Chris Iannello, Electrical Power Discipline Deputy.

Brian Abresch of the Wallops Electrical Engineering Branch tests 

avionics used on the CM water drop assessment.

45
2011 NESC TECHNICAL UPDATE

Center Focus

Learning through the NESC Assessments

Brandon Florow is a former 

NESC Resident Engineer who 

participated in several interesting 

NESC studies. Mr. Florow worked 

on the composite overwrapped 

pressure vessel (COPV) stress 

rupture testing and also acted 

as the test conductor for the first 

phase of the Orion CM seat attenuation strut testing. In addition, he prepared the test plans 

and supported all three phases of 

strut testing. Mr. Florow was also 

on the Quick-Look Data Team 

and the Strain Gage Instrumentation Team for the Crew Module Water Landing and Modeling Assessment. “Being a 

young engineer, the NESC offered me an opportunity that 

I couldn’t get anywhere else. It allowed me to work with 

system experts both within and from outside my field, gain 

an overall Agency perspective, and expand my network of 

colleagues.”

Engineering Safer Landing Systems for Spacecraft

John Baker, systems engineer, 

has studied and quantified the 

risks in multiple versions of Orion 

CM landing systems. “I have led 

a number of successful assessment teams since 2006 for the 

NESC that have resulted in design changes to the Orion CM,” 

Mr. Baker stated. These studies 

included risk trades between 

water and land landing variants. 

His most recent assessment involved Orion CM water landing 

impacts and how to model them. “I had a diverse interCenter team that worked very hard and produced an outstanding test data set for the Orion Multi-Purpose Crew 

Vehicle Program and other future teams that want to land 

capsules back on Earth. Leading teams for the NESC has 

been a real honor for me and has broadened my experience base both technically and as a manager.” 

Improving Engineering Knowledge of Composite 

Pressure Vessels

Dr. Lorie Grimes-Ledesma is the chair of the NESC 

CPVWG. The CPVWG is chartered to understand and 

communicate issues and risks associated with legacy 

and state-of-the-art COPVs and all-composite tanks. In 

the 4 years that Dr. Grimes-Ledesma has led the Agencywide CPVWG, the group has provided technical support 

to several programs and projects throughout NASA

including the International Space Station, Orion MultiPurpose Crew Vehicle, the Juno Probe, and the Global 

Precipitation Measurement Satellite. Dr. Grimes-Ledesma 

is also the technical lead for the NESC COPV life

prediction model development task and supports the 

NESC Materials TDT. Dr. Grimes-Ledesma’s engagement 

with the CPVWG has enabled her to learn from and 

participate in solving a larger range of issues that span the 

NASA community.

The Jet Propulsion Laboratory 

(JPL) participated in the NESC 

assessments for the Science and 

Human Exploration and Operations 

Mission Directorates and supported 

the NASA Technical Fellows and their 

Technical Discipline Teams (TDTs). 

JPL led the Orion crew module (CM) 

water landing testing with the second phase of 

testing now complete. The results have improved 

the CM design models and CM design and has 

and will continue to influence future testing plans

and design options. The NESC Composite 

Pressure Vessel Working Group (CPVWG) 

has developed a test plan for stress rupture (a 

composite overwrapped pressure vessel failure 

mode) based on needs identified in previous 

NESC assessments and is proceeding 

with a stress rupture model development 

program. JPL supported NESC 

assessments for the Science Mission 

Directorate, which include software 

tools, battery usage in operational 

missions, and pyrovalve reliability. JPL

is also developing the thermal 

performance database to gather historical data 

on thermal protection system performance 

and provide an easy access to that data.

The Robotics TDT, led by the NESC Chief Scientist 

at JPL, is working several tasks to advance 

robotic exploration, including the entry, descent, 

and landing (EDL) task, in which a database

was developed to capture at-risk EDL data to 

benefit future spacecraft designs. 

R. Lloyd

Keith

John Baker

Jet Propulsion Laboratory

JPL

employees

supporting

NESC

assessments 

93:

Brandon Florow

NESC Chief 

Engineer at 

JPL

Dr. Lorie Grimes-Ledesma examines composite pressure vessels 

undergoing life testing at WSTF.

46
The NESC’s boilerplate Orion crew module is hoisted to drop height 2011 NESC TECHNICAL UPDATE
2011 NESC TECHNICAL UPDATE

Center Focus

The Johnson Space Center (JSC) 

and the White Sands Test Facility 

(WSTF) provided engineering analysis, 

design, and test expertise for the 

safe completion of the Space Shuttle 

Program (SSP); supported continuous 

operation of the International Space 

Station (ISS); and participated in the 

development of the Multi-Purpose Crew 

Vehicle (MPCV) spacecraft as well as other new 

systems. The NESC personnel at JSC supported 

missions in real time on both the SSP and ISS 

Mission Management Teams. The NESC Deputy 

Director for Safety and NASA Technical Fellows 

for Life Support/Active Thermal, Loads and 

Dynamics, and Passive Thermal are resident at 

JSC. The Technical Fellows at JSC provided key 

expertise to publicly released Agency roadmaps 

spanning 14 technology areas and supported 

presentations to the National Research Council. 

These Technical Fellows, along with Technical 

Fellows in Nondestructive Evaluation, Materials, 

and Structures and their Technical Discipline 

Teams, led independent analyses to investigate 

the root cause of the SSP external tank 

intertank foam and stringer anomaly. 

Their support extended throughout 

the process of resolving this issue, 

including the STS-133 delta Flight 

Readiness Review and STS-134 and 

STS-135 missions. The NESC personnel 

have contributed to transitioning and 

advancing exploration and were involved 

in MPCV spacecraft entry/landing systems, 

thermal control and protection, life support, 

and loads/dynamics. The NESC technical 

expertise was also applied at commercial crew 

development design reviews and technical 

interchange meetings.

In addition, the NESC engaged in several 

assessments and tests at JSC’s WSTF in areas 

including pyrovalve booster interface temperature 

measurements and reliability assessments for 

expendable launch vehicle payloads, testing and 

analysis of composite pressure vessels (CPV), 

and development of a laser profilometer that 

maps defects on both the interiors and exteriors 

of cylindrical CPVs.

NESC TDT Support to James Webb Space Telescope

Dr. Eugene Ungar is a member of the NESC’s Life 

Support/Active Thermal Technical Discipline Team and 

led the NESC’s multi-Center JWST Sunshade Venting 

Analysis Team. His team independently assessed the 

analyses and tests being used by the JWST Program to 

demonstrate that the ascent venting of the JWST Kapton 

film sunshade will be efficient enough to prevent the 

sunshield membrane from being overpressurized and 

damaged. The team performed an informal blowing test 

to gain more understanding of the billowed shape of the 

folded and secured membranes during ascent and also 

tested membrane Helmholtz instability. These key tests 

allowed the team to conclude that longitudinal flow along 

and within the stowed membrane was unlikely to lead to 

flapping instabilities. “Working on a multi-Center team 

expands your horizons,” Dr. Ungar stated. “Stretching 

technically into a field unrelated to your area of expertise 

is challenging. Taken together, they result in a very fulfilling 

task.”

ISS Radiator Face Sheet Failure Investigation

Marshall Neipert, aerospace engineer, was a key member 

of the NESC root cause investigation for the ISS radiator face sheet failure. He leveraged expertise at several 

Centers to understand and organize available data. With 

limited post-event data and on-orbit imagery and other 

measurements, he developed a physics-based LSDYNA 

model of a radiator pressurized to failure, 

which showed the failure propagation and 

final state of the face sheet. The model 

demonstrated many of the failure characteristics observed in the on-orbit radiator 

imagery and its usefulness in assessing 

the plausibility of a pressure event as a 

root cause. “To develop these techniques, 

I leaned on modeling experts at GRC and 

ARC. I have since used some of the techniques on the MPCV Program. The efficiency, broad expertise, and a team-oriented atmosphere 

led to the success of the assessment effort,” Mr. Neipert 

stated.

Dr. Nancy J.

Currie

Johnson Space Center

JSC

employees

supporting

NESC

assessments 

57:

Dr. Eugene Ungar of the JSC Crew and Thermal Systems Division.

“

... the efficiency, broad expertise, and 

a team-oriented atmosphere led to the 

success of the assessment effort

— Marshall Neipert

”

NESC Chief 

Engineer at 

JSC 

Marshall

Neipert

48
2011 NESC TECHNICAL UPDATE

Center Focus

Pyrotechnic Testing and Analysis

Regor Saulsberry of the WSTF Laboratory Office led two 

pyrotechnic assessments for the Propulsion Technical 

Discipline Team (TDT). The first, the Pyrovalve Booster 

Interface Temperature Measurement Assessment, compared legacy aluminum primer chamber assemblies 

(PCAs) against a new stainless steel PCA and provided 

other high-value data to programs. The test data indicated 

that the stainless steel PCA with V-shaped flame channels averaged 316 C (600 F) hotter at the booster charge 

interface than the aluminum PCAs with Y-shaped channels. When the two NASA standard initiators were fired 

simultaneously, neither channels produced a booster interface temperature high enough for reliable ignition. Ignition temperatures were adequate with firing skew greater 

than 250 microseconds, but a larger margin was recommended for flight applications. The second, the Pyrovalve 

Reliability Assessment for Expendable Launch Vehicle 

Payloads, used experts from several other TDTs and Centers to provide needed guidance for NASA payload safety 

policy regarding safe pyrovalve use in payloads propulsion systems using hazardous propellants. “It is great to 

have Technical Fellows with strong TDTs available to us,” 

explained Mr. Saulsberry. “This made the right technical 

resources available in a very timely manner.” Mr. Saulsberry also helped develop nondestructive laser profilometers and eddy current scanners to characterize defects in 

composite pressure vessels. 

Launch Abort System Design

The NESC is engaged in a conceptual 

design effort for development of a launch 

abort system risk mitigation flight test vehicle. Dr. Jennifer Madsen of the Aeroscience 

and Flight Mechanics Division serves as 

the lead for the guidance, navigation, and 

control development, and Joseph Cook, 

Energy Systems Division, is the lead for design of the attitude control propulsion system. Both Dr. Madsen and Mr. Cook cited 

the benefits of working on a multi-Center 

project. “Working across Centers and 

across disciplines allows for the sharing of 

tools and analysis techniques to benefit the 

team members and the technical product,” 

Dr. Madsen observed. Mr. Cook has found 

the work “refreshing” and noted, “It’s nice 

to work in such a positive environment with 

everyone pulling together to succeed.”

“ Working across Centers and 

across disciplines allows for the 

sharing of tools and analysis techniques to benefit the team members and the technical product.

— Dr. Jennifer Madsen 

”

WSTF Pyrotechnic 

Testing and Analysis 

Team analyst, John 

Anderson (right) 

presents a finite 

element analysis to 

assessment lead 

Regor Saulsberry 

(center), Steve 

Woods, Expendable 

Launch Vehicle 

Deputy Lead (left), 

and Steve McDougle 

PCA Deputy Lead, 

(seated).

Dr. Jennifer

Madsen

Joseph

Cook

49
2011 NESC TECHNICAL UPDATE

Center Focus

Stephen A. 

Minute

The NESC was involved in multiple 

activities and projects at Kennedy 

Space Center (KSC). Likewise, KSC 

continues to provide support and expertise to a wide variety of NESC assessments and testing across the 

Agency. KSC engineers provided

expertise on 12 different NESC Technical Discipline Teams (TDT), including Electrical 

Power, Flight Mechanics, and Loads and Dynamics. The KSC expertise plays a role in resolving 

many of the Agency’s difficult problems and was 

engaged in a variety of NESC assessments and projects affecting ground 

processing and operations at KSC,

including space shuttle external tank 

(ET) stringer cracks; ET hydrogen vent 

umbilical leakage; orbiter auxiliary power 

unit heater anomaly; Commercial Crew 

Program requirements development and 

partner insight support; Doppler radar profiler for 

launch winds; ground and launch systems processing technology roadmap review; and avionics 

embedded electronic systems design training.

Going Where the Evidence and Data Leads You

Dr. Phillip Tang, an electronics engineer in the 

Engineering’s Electrical Division, supported the NESC 

effort on the Department of Transportation National 

Highway Traffic Safety Administration Toyota Unintended 

Acceleration Investigation. He performed tests on various 

models of engine control simulators for both test and 

complaint vehicles. Together, the NESC team determined 

the effects that faulty signals have on the engine control 

module and the resultant throttle position/unintended 

acceleration. The team modeled and analyzed the various 

circuit parameters and then validated their analysis 

and failure scenarios through testing. Not only did this

effort aid the National Highway Traffic Safety Administration 

in their technical investigations, it also fostered NASA 

inter-Center and inter-Agency working relationships.

Dr. Tang stated the one lesson he learned was “Go where 

the evidence and data leads you.”

Developing Agency-Wide Embedded

Electronics Skills

Dr. Christopher Ianello serves as the Discipline Deputy for 

the Electrical Power TDT and is also an active member of 

the Avionics TDT. At KSC, he is a Deputy Chief Engineer 

for the Commercial Crew Program. He supported many of 

the NESC assessments with both TDTs and has employed 

laboratories at KSC, GSFC, and MSFC. With the Avionics 

TDT, he is implementing a discipline stewardship initiative 

to develop new skills in embedded electronics through 

an initial startup class at KSC with hopes of expanding 

across the Agency. “The NESC, in a few short years,

has done more to connect discipline specialists Agencywide with one another than any previous activity I have 

been a part of.” 

Predicting Rocket Plume Impingement on Launch

Pad Structures

Dr. Bruce Vu, fluid systems lead in the Mechanical 

Engineering Division’s Design Analysis Branch, was 

an active member of the NESC’s multi-Center/industry 

partner assessment of Orbital Sciences Corp. (OSC) 

Stage Testing Plan for Taurus II at GSFC’s Wallops Flight 

Facility. He developed a new capability in predicting rocket 

plume exhaust with chemical reactions. The capability to 

make accurate prediction of plume exhaust is important in 

the thermal analysis of ground systems—accurate plume

definition leads to accurate plume

impingement prediction on launch pad 

structures. The new capability uses 

finite-rate chemistry to accurately predict 

the launch-induced environment due to 

combustion of fuel and liquid oxygen. 

“Not only did I contribute to the project, 

but I also learned from other team 

members, especially how the commercial 

space industry conducts their business.” The collaboration 

with OSC led to a technical paper on this new predictive 

capability.

Dr. Bruce Vu

NESC Chief 

Engineer at 

KSC

KSC

employees

supporting

NESC

assessments 

52:

Dr. Phillip Tang of the Electrical Division in KSC engineering.

Dr. Christopher Ianello is developing an Agency-wide embedded 

electronics course.

Kennedy Space Center

50
2011 NESC TECHNICAL UPDATE

Center Focus

Walter C.

Engelund

Jay

Brandon

Launch Abort System Attitude Control Development

Gene Heim is the flight mechanics lead for the launch 

abort system risk mitigation flight test vehicle activity. 

As part of his duties, he has organized an experienced 

team consisting of members from the Max Launch Abort 

System (MLAS) and Ares I-X Flight Test Programs and 

has helped in the development of models and simulations being used to design 

and analyze the launch abort system. His 

analysis has impacted the architecture of 

the MLAS concept by demonstrating the 

benefits of adding roll control to the attitude control system. Mr. Heim has used 

his creativity and ingenuity in developing 

plans for reducing risk of the eventual 

flight demonstration, including the reuse of core models validated during the 

successful Ares I-X Flight Test Program, and plans for dynamic wind tunnel tests to assess closed-loop control of 

the system. “This project has given me the opportunity to 

work with extraordinary people across the Agency, and 

see sides of NASA I had not experienced before.”

Thermal Model Development

Ruth Amundsen, aerospace engineer, is a member of the 

Passive Thermal Technical Discipline Team, and was the 

NESC thermal lead for the space shuttle external tank 

stringer investigation. For this assessment, she was responsible for developing 

a thermal model of the cracked stringer 

area around the liquid oxygen tank and 

subjecting it to the same conditions as 

on the day of the crack, as well as test 

conditions that were used to correlate the 

models. Ms. Amundsen mapped the thermal variations for all the transient timelines and provided results to the structural 

lead, who analyzed the levels of stress 

and deflection due to those thermal gradients. The thermal model was compared 

to the tanking test data with excellent 

correlation. The complexity of the model needed, coupled with the short time 

span available, forced the improvement of methods for

re-using a structural mesh for portions of the thermal model. Analyses were conducted on a desktop PC

running the Thermal Desktop software, which is used 

Agency-wide. “The experience of comparing the thermal models done by three different organizations using 

different tools and methods was very educational. It was

exciting, fast-paced work.”

Applying Photogrammetry to Spacecraft Landing

Kurt Severance is a photogrammetry analyst responsible 

for computing the rigid body motion for all the drop tests 

in phase I and phase II of the Crew Module Water Landing 

Modeling Assessment (CMWLMA). By extending a photogrammetry technique originally developed 

for the MLAS flight analysis, he measured 

the six degrees of freedom motion of the 

crew module during freefall, water contact, 

and partial submersion. These highly accurate data products became the ground 

truth for comparison to all other measured 

datasets. “I thoroughly enjoyed being a 

member of the high-performing CMWLMA 

team. The success of the photogrammetry was the result of an effective collaboration among personnel in the NESC, LaRC 

Engineering Directorate, LaRC Research 

Directorate, LaRC Office of Chief Information Officer, WFF, and the Aberdeen Test 

Center.”

Langley Research Center

 (LaRC) continues to support

the NESC mission to address 

the Agency’s and nation’s highrisk programs and projects. 

LaRC personnel have contributed technical expertise in the 

areas of structures; materials; 

nondestructive evaluation; flight

sciences; fabrication technology; loads 

and dynamics; computational fluid dynamics; mechanisms; guidance, navigation, 

and control; flight mechanics; and avionics. NESC activities at LaRC include the 

launch abort system risk mitigation flight 

test vehicle, where preliminary design has 

been developed to provide flight validation of the capsule abort option

using actively controlled systems;

autonomous aerobraking capability development; composite 

crew module analysis; Orion 

crew module structures analysis and water landing testing; 

shell buckling knockdown factor

development from large-scale 

testing; space shuttle external tank

stringer nondestructive testing and analyses; flight simulation model exchange; 

and International Space Station solar

array boom analysis. The NASA Technical

Fellows for Aerosciences, Flight Mechanics, Materials, Nondestructive Evaluation, 

and Structures are resident at LaRC.

Gene

Heim

Ruth Amundsen with thermal modeling software.

Kurt Severance with boilerplate Orion 

CM at the Aberdeen Test Center.

LaRC

employees

supporting

NESC

assessments 

171:

NESC Chief 

Engineer at 

LaRC

(Acting)

NESC Chief 

Engineer at 

LaRC

Langley Research Center

51
2011 NESC TECHNICAL UPDATE

Center Focus

Developing a New Sounding Rocket Sustainer Motor 

Ben Davis and Dale Jackson, aerospace engineers, have 

been working at NASA for 4 and 5 years, respectively, 

and are contributing to the solid rocket sustainer motor 

(SRSM) development through the design of the nozzle 

assembly and propellant grain and igniter. 

This development enabled Mr. Davis 

to participate in systems engineering 

activities with groups across MSFC. He 

has gained experience collaborating with 

subject matter experts at other Centers, 

federal agencies, and industries on topics 

ranging from propellant casting/curing 

to nozzle hardware cost and schedule 

data. Mr. Davis stated, “The NESC SRSM 

Program has benefited me by offering 

valuable experience in solid rocket motor 

design and systems engineering. No two 

motors are alike, and each opportunity 

to design and build a rocket motor is an 

invaluable learning experience.”

The SRSM development has allowed

Mr. Jackson to gain experience by working 

within design constraints and testing

the performance characteristics of different propellant 

grain configurations. He has expanded his technical 

contacts to include entities within the Department of 

Defense. Working with these entities on igniter design has 

accelerated his knowledge by eliminating unnecessary 

trial and error methods that he might have encountered 

without access to these subject matter experts.

Mr. Jackson stated, “This type of project is a great way 

for NASA engineers to get design experience that is 

usually only obtained by working for a solid rocket motor 

manufacturer, which is certainly priceless!” 

Support of Shell Buckling Testing

George Olden and Jacob Morton have been working at 

NASA for 3 years and have contributed to the success 

of the Shell Buckling Knockdown Factor (SBKF) Project 

through project management, system and test engineering, design support to the test buildup, instrumentation, 

and testing of the external tank test article #1 (ETTA1) in 

March 2011. For the ETTA1 test, Mr. Olden served as the 

assistant test engineer. In addition to his standard duties 

of managing the design and buildup of test fixtures, test 

setup, and instrumentation, Mr. Olden’s other responsibilities included design of a new control room layout and 

large-scale setups for emerging 

technologies such as video image 

correlation and high-speed cameras. Mr. Olden stated, “Working 

with the NESC allowed me to get 

a systems-level perspective of 

technical challenges facing the 

Agency and gave me more job 

satisfaction knowing the work I 

was doing will fundamentally enhance NASA’s structural design 

process.”

Mr. Morton is a test technician 

who supported the SBKF ETTA1 

test. Along with the myriad tasks 

during this size project (e.g., load 

line installation, instrumentation, test setup), Mr. Morton 

was responsible for the setup and operation of the highspeed cameras. These cameras were essential in providing details of initial buckling location and propagation 

within milliseconds of the event. Mr. Morton designed a 

mounting structure and installed eight cameras at locations around the load test annex to enable 360-degree 

coverage of the 27.5-foot-diameter by 20-foot-tall test article. Mr. Morton stated, “I have always enjoyed a challenge, and this was the largest high-speed setup we have 

ever done. We worked many days and very long hours to 

build up to an absolutely successful test day, and I am 

proud of that.”

The Marshall Space Flight Center 

(MSFC) has provided engineering, 

scientist, and technician support to 

over 35 NESC assessments and investigations. These investigations involved 

the areas of exploration systems, space 

operations, science, and crosscutting 

discipline activities. Some of the more 

significant investigations include: shell buckling 

knockdown factor testing, sounding rocket 

sustainer motor design and development, Taurus 

II stage testing, SSC A-3 test stand structural 

analysis, cross-track infrared sounder 

instrument frame fabrication, Doppler 

radar profiler data analysis, and Orion 

launch abort system risk mitigation. The 

NASA Technical Fellow for Propulsion, 

and the Discipline Deputies for the 

Human Factors and Nondestructive 

Evaluation Technical Discipline (TDTs) 

are resident at MSFC. MSFC provides critical 

support to 15 of the NESC TDTs with over 100 

engineers and scientists. Additionally, a MSFC 

employee served as an NESC resident Engineer.

Dale

Jackson

Ben

Davis

NESC Chief 

Engineer at 

MSFC

Jacob Morton prepares for a lift in front of the ETTA1.

George Olden in front of 

the ETTA1 with photogrammetry target overlay 

applied.

MSFC

employees

supporting

NESC

assessments 

133:

Marshall Space Flight Center

Steven J.

Gentz

52
2011 NESC TECHNICAL UPDATE

Center Focus

The Stennis Space Center (SSC) provided expert technical support to 

NESC activities, including the A-3 test 

stand structural dynamics analysis and 

AJ-26 engine radiometer measurements 

in support of the NESC’s assessment of 

Taurus II. SSC has members on several of the NESC’s Technical Discipline 

Teams, and an SSC employee served as an NESC 

Resident Engineer. The NESC also delivered

expertise and assessments that directly benefited SSC projects by providing subject

matter materials selection expertise to the High

Pressure Industrial Water Piping Infrastructure 

Replacement Project and delivering a comprehensive structural dynamics analysis of the A-3 

test stand. The NESC activities employed the 

unique capabilities of SSC’s Engineering and Test Directorate in support of the 

A-3 test stand structural dynamics analysis. The A-3 test stand is being designed

and built to provide simulated altitude 

rocket engine tests using a low-pressure 

test cell which is evacuated by a twostage steam diffuser/ejector system. 

During operation, 5,600 pounds/second of steam 

and rocket exhaust flowing through the diffuser/

ejector system and its supersonic discharge

to atmosphere will produce a significant vibroacoustic environment in and around the test 

stand. The NESC was asked to perform an

analysis of the structural dynamic response of 

the stand and its components to the predicted 

vibroacoustic loading.

A-3 Test Stand Analysis

Dr. Howard Conyers, structural analyst, conducted vibroacoustic analysis of the ground-level signal conditioning 

building (SCB) near the base of the A-3 test stand. Collaborating with team members at MSFC, he used ANSYS 

structural mechanics software to model the SCB and 

analyze the effects of acoustically induced vibrations.

Dr. Conyers also gained valuable exposure to the Nastran finite element modeling software used by the team, 

learned new techniques for vibration analysis, and was introduced to new intra-Agency contacts. “Working with the 

NESC showed me that multi-Center cooperation allows us 

access to Agency-wide expertise not available locally.”

Jody Woods, A-3 Chief Engineer, had multiple roles in the 

A-3 Test Stand Structural Dynamics Assessment as the 

assessment requester, team member, and a stakeholder. 

In his role as team member, he provided design support, loads data, and environmental conditions needed 

for a successful analysis. As a stakeholder, he was very 

pleased with the results of the assessment and the depth 

of the analysis. “The NESC has been a valuable resource 

to the A-3 Project. We had test stand structural dynamics 

concerns related to design assumptions that the project 

could not address, and we looked to the NESC for assistance. The team of experts assembled by the NESC 

did an outstanding job performing the complex analyses 

required to address these dynamics issues and allay any 

concerns,” Mr. Woods stated. This assessment exposed 

SSC personnel to new modeling software packages and 

new finite element analysis techniques. “This opportunity has opened the door for SSC to use state-of-the-art 

software to model and understand difficult problems like 

these that arise when testing the rocket engines of tomorrow,” Mr. Woods stated.

Subscale Diffuser Assessment

The NESC E-3 Subscale Diffuser Assessment was a great 

way for Dr. Allgood to apply his extensive exhaust plume 

diagnostic experience and to learn more about exhaust 

plume acoustic loads. Subscale diffuser testing was conducted in the SSC E-3 test area to gather data to assist 

with the A-3 test stand design. Using the data gathered 

during subscale diffuser testing, he was able to predict the 

acoustic loads for the full scale test stand. This assessment was his first exposure to the acoustic loading aspect of exhaust plume diagnostics and added depth to his 

American Institute of Aeronautics and Astronautics (AIAA) 

paper documenting his analysis. “This project allowed me 

the chance to learn new techniques for modeling exhaust 

plume acoustics and to publish an AIAA paper detailing 

the results.”

NESC Chief 

Engineer at 

SSC

Jody Woods, A-3 Chief Engineer (left), and Dr. Howard Conyers, 

structural analyst, examine plans for the signal conditioning building, shown in the foreground of the A-3 test stand.

Dr. Daniel Allgood investigating acoustic loads on the A-3 test stand.

SSC

employees

supporting

NESC

assessments 

13:

Stennis Space Center

Michael D. 

Smiles

53
2011 NESC TECHNICAL UPDATE

Awards & Recognition

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 prevailing 

engineering truths

Bryan O’Connor

In recognition of unwavering advocacy, 

leadership, and commitment in the formulation and continued successful operation of the NASA Engineering and 

Safety Center

NESC Leadership Award

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

Alden C. Mackey

In recognition of outstanding technical 

leadership of NESC assessments and 

consultations in the loads and dynamics technical area and in support of the 

Loads and Dynamics Technical Discipline Team 

Daniel A. Pruzan

In recognition of exceptional engineering leadership for the NESC’s assessment of the Constellation Program 

Launch Abort Vehicle Stability Augmentation and the Shuttle Carrier Aircraft 

Phantom Ray Delivery Flight

NESC Engineering

 Excellence Award

Honors individual accomplishments of 

NESC-job related tasks of such magnitude and merit as to deserve special 

recognition

Robert B. Davis

In recognition of engineering excellence and outstanding leadership as the

technical lead of the highly complex 

A-3 Test Stand Structural Dynamics

Analysis Assessment

Courtney S. Flugstad

In recognition of engineering excellence and outstanding leadership as the 

Program Manager for the NESC’s Shell 

Buckling Knockdown Factor Project

Philip D. Hattis

In recognition of Guidance, Navigation, 

and Control engineering excellence for 

the Impact of Orion Service Module 

Propellant Slosh on Ares-I Flight Control 

NESC Assessment

Thomas W. Jones

In recognition of engineering excellence 

in the successful design, implementation, and operation of the photogrammetry measurement system and center 

of gravity determination with photogrammetry

William C. Rose

In recognition of engineering excellence 

in the support of the Boeing Phantom 

Ray Unmanned Air Vehicle delivery on 

the NASA Shuttle Carrier Aircraft

Kurt Severance

In recognition of engineering excellence 

in the development and application of 

new photogrammetry methods which 

enabled accurate measurement of the 

boilerplate Orion crew module trajectory during water entry testing

NESC Honor Award Recipients for 2011

Left to right: Kyong Song, Alliant Techsystems, Inc.; James Reeder, LaRC; Bruce Vu, KSC; Daniel Pruzan, Nielsen Engineering and Research; 

Louise Strutzenberg, MSFC; Richard Brewer, CSC Applied Technologies; Jay Warren, LaRC; Ben Davis, MSFC; Courtney Flugstad, KSC; Douglas 

Jones, Jacobs Engineering; Pat Floyd, United Space Alliance; Albert Zimmerman, The Aerospace Corporation; Philip Hattis, Charles Stark Draper 

Laboratory; Brian Abresch, WFF; Robert Wingate, MSFC; Kurt Severance, LaRC; Daria Topousis, JPL; Thomas Jones, LaRC; Tim Wilson, NESC 

Deputy Director/presenter; Jeffrey Cerro, LaRC; Ralph Roe, Jr., NESC Director/presenter; Mark Hilburger, LaRC; Patrick Forrester, NESC Chief 

Astronaut/presenter. Not pictured: Bryan O’Connor, NASA HQ retired; Alden Mackey, Barrios Technology; and William Rose, Rose Engineering 

and Research, Inc.

54
2011 NESC TECHNICAL UPDATE

Awards & Recognition

NESC Engineering

 Excellence Award

Continued

Louise L. Strutzenberg

In recognition of engineering excellence in computational fluid dynamics 

modeling and analysis for the Taurus 

II first stage hot-fire test NESC risk

assessment 

Bruce T. Vu

In recognition of engineering excellence 

in plume impingement, acoustics, and 

thermal modeling for the Taurus II first 

stage hot-fire NESC risk assessment

Albert H. Zimmerman

In recognition of engineering excellence for innovative battery test development in support of the identification 

of the Wilkinson Microwave Anisotropy 

Probe On-Orbit Battery Anomaly 

NESC Administrative

Excellence Award

Honors individual accomplishments or 

contributions that contributed substantially to support the NESC's mission

Daria E. Topousis

In recognition of exceptional and dedicated support to the NASA Technical 

Fellows in the development and continued enhancement of their NESC Technical Discipline Team Communities of 

Practice sites on the NASA Engineering 

Network

NESC Group 

Achievement Award

Honors a group of employees comprised of government and non-government personnel for outstanding accomplishment through the coordination of 

individual efforts that have contributed 

substantially to the accomplishment of 

the NESC’s mission

A-3 Test Stand Structural

Dynamics Analysis Team

In recognition of outstanding contributions and innovative approaches to 

modeling complex structural interfaces 

with propellant supply systems, steam 

generation, and diffuser/ejector 

Composite Pressure Vessel Life

Prediction (Reliability) Model

Development Analytical Subteam

In recognition of outstanding contributions in the cross-functional problem 

solving and methods development for 

Composite Pressure Vessel Life Prediction Model Development 

Crew Module Water Landing

Modeling Assessment Team

In recognition of outstanding contributions to the water drop-tests of a fullscale boilerplate crew module on an 

accelerated schedule 

NASA Standard Development

for Spaceflight Fastening

Systems Team

In recognition of outstanding contributions to NASA and industry collaboration in the development of a NASA standard for threaded fastening systems in 

spaceflight hardware

NASA Standard for Models and 

Simulations Recommended Practice Guide Project Team

In recognition of outstanding achievement in the development of a guidebook for the NASA Standard for Models 

and Simulations 

Reinforced Carbon Carbon Fracture 

Mechanics Analysis Team

In recognition of outstanding fracture 

mechanics analysis contributions to the 

understanding of the Reinforced Carbon Carbon Spallation phenomenon

Shell Buckling Knockdown

 Factor Project Team

In recognition of outstanding achievement in the highly successful test of the 

27.5 foot diameter External Tank Test 

Article 1 

Shuttle Carrier Aircraft

Aero-Structural Dynamics Team

In recognition of outstanding aerostructural analysis and flight measurements in support of the Boeing Phantom Ray Unmanned Air Vehicle delivery 

on the NASA Shuttle Carrier Aircraft 

Shuttle Processing Mishap

Recurring Cause Study Team

In recognition of outstanding achievement in proactively reducing the risks 

associated with Shuttle fly-out based 

on the results of the Shuttle Processing 

Mishap Recurring Cause Study

Space Shuttle Program External 

Tank Intertank Stringer Cracking

Investigation Team

In recognition of exemplary technical 

support in the resolution of the Space 

Shuttle Program External Tank Intertank Stringer Structural Failure 

Wilkinson Microwave Anisotropy 

Probe Battery Operations Problem 

Resolution Team

In recognition of outstanding contributions in identification of the Wilkinson 

Microwave Anisotropy Probe On-Orbit 

Battery Anomaly and crucial support in 

extending the mission to completion

55
2011 NESC TECHNICAL UPDATE

Awards & Recognition

AIAA names Jay Brandon Engineer of the Year

Jay Brandon, a senior research

engineer at NASA’s Langley Research 

Center (LaRC), and acting NESC Chief 

Engineer at LaRC, won the award for 

his leadership of the Ares I-X Guidance, 

Navigation, and Control team. The 

Ares I-X test rocket made a 2-minute 

powered flight October 28, 2009, 

and splashed down about 150 miles 

down range from the Kennedy Space 

Center—demonstrating that the new, very tall, and thin 

design could be controlled autonomously. The flight test 

provided NASA with an enormous amount of data that is 

being used to improve the design and safety of the next 

generation of American spaceflight vehicles.

NASA Team Receives Service to America Medal

NESC Core Team members 

Dr. Ivatury S. Raju Receives ICCES Medal

Dr. Ivatury S. Raju, NASA Technical 

Fellow for Structures, received a 

Life-Time Achievement Medal from 

the 2011 International Conference 

on Computational and Experimental 

Engineering and Sciences (ICCES) in 

Nanjing, China, for recognition of his 

contributions to “Structural Integrity and 

Durability.” This medal is awarded to an 

individual for sustained and significant contributions in the 

form of research, teaching, and service to the community, 

in any area germane to the ICCES series of conferences. 

NASA\Paul E. Alers

NASA Administrator Charles Bolden, right, presents the National 

Security and International Affairs Medal to Michael Duncan; J.D. 

Polk; and Clinton Cragg, NESC Principal Engineer, at left. The three 

were honored in September at the 2011 Samuel J. Heyman Service 

to America gala in Washington, D.C., for their contributions to the 

Chilean miner rescue effort. 

56
STS-134 Space Shuttle Endeavor docked at the International Space Station 2011 NESC TECHNICAL UPDATE
Core Leadership Team

Ralph R. Roe, Jr.

NESC Director

Mr. Ralph R. Roe, Jr. is the NESC’s Director at Langley 

Research Center (LaRC). Mr. Roe has over 28 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.

Timmy R. Wilson

NESC Deputy Director

Mr. Timmy R. Wilson is the NESC’s Deputy Director at Langley Research Center. 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 30 years of engineering and management experience supporting the Space Shuttle Program.

Michael P. Blythe

NESC Deputy Director for Safety

Mr. Michael P. Blythe is the NESC’s Deputy Director 

for Safety and is resident at the Johnson Space Center (JSC). Prior to joining the NESC, Mr. Blythe served 

as the Acting Assistant Associate Administrator in the 

Office of the Administrator at NASA Headquarters.

Mr. Blythe came to the Office of the Administrator from the Office of 

Chief Engineer, where he served as the Director for the Engineering 

and Program/Project Management Division. In this capacity, he was 

responsible for establishing and implementing Agency engineering and 

program/project management policy, procedures, and processes to 

improve the efficiency and success of NASA’s investments.

Dawn M. Schaible

Manager, Systems Engineering Office

Ms. Dawn M. Schaible is Manager of the NESC’s 

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 24 years of experience in systems engineering, 

integration, and ground processing for the Space Shuttle and International Space Station Programs. 

Daniel J. Tenney

Manager, Management and

Technical Support Office

Mr. Daniel J. Tenney is Manager of the NESC’s Management and Technical Support Office at Langley

Research Center (LaRC). Prior to joining the 

NESC, Mr. Tenney served as the Deputy Chief Financial Officer for

Systems at LaRC, where he managed over 30 information systems.

Mr. Tenney has 22 years of professional financial, accounting, and

systems experience at NASA.

Dr. Daniel Winterhalter 

Chief Scientist

Dr. Daniel Winterhalter is the NESC’s Chief Scientist 

and is resident at the Jet Propulsion Laboratory (JPL). 

Dr. Winterhalter has over 33 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 operation of complex spacecraft and space science missions. 

Patrick G. Forrester

NESC Chief Astronaut

Mr. Patrick G. Forrester is the NESC’s Chief Astronaut 

and is resident at the Johnson Space Center (JSC). 

Mr. Forrester began his NASA career in 1993 after 

serving in the U.S. Army. As a Master Army Aviator he 

logged over 4800 hours in over 50 different aircraft. He was selected 

as an astronaut candidate in 1996 and flew on STS-105 (2001), STS117 (2007), and STS-128 (2009). He has logged over 950 hours in 

space, including four spacewalks totaling 25 hours and 22 minutes of 

EVA time. 

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 36 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

2011 NESC TECHNICAL UPDATE

Biographies

58
NESC Principal Engineers

NESC Chief Engineers

NESC Chief Engineers Continued

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 33 years of experience in supervision, command, and ship-borne nuclear safety. 

Dr. Michael G. Gilbert

NESC Principal Engineer

Dr. Michael G. Gilbert is a Principal Engineer with 

the NESC at Langley Research Center (LaRC).

Dr. Gilbert was formerly the NESC Chief Engineer at

LaRC. Before joining the NESC, he was Head of the 

LaRC Systems Management Office. Dr. Gilbert has over 33 years 

of engineering, research, and management experience with aircraft, missile, spacecraft, Space Shuttle, and International Space

Station Programs.

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 22 years of experience in managing 

projects and test facilities.

Jay Brandon

NESC Chief Engineer (Acting) 

Mr. Jay Brandon is Acting NESC Chief Engineer at 

Langley Research Center (LaRC). He most recently 

served as the Guidance, Navigation, and Controls 

lead for the Ares I-X. Mr. Brandon has over 27 years 

of experience in flight dynamics performing wind

tunnel testing and piloted simulation and flight testing primarily of highperformance airplanes.

Dr. Nancy J. Currie

NESC Chief Engineer

Dr. Nancy J. Currie is the NESC's Chief Engineer at 

Johnson Space Center (JSC). Dr. Currie came to the 

NESC from JSC, where she served as the Deputy

Director of the Engineering Directorate. Dr. Currie has 

over 23 years of experience in robotics and human 

factors engineering. Selected as an astronaut in 1990, Dr. Currie is a

veteran of four space shuttle missions and has accrued 1000 hours 

in space. 

Dr. John H. Day

NESC Chief Engineer (Acting)

Dr. John H. Day is Acting NESC Chief Engineer at Goddard Space Flight Center (GSFC). Dr. Day was formerly 

Chief of the Electrical Engineering Division at GSFC. 

Dr. Day has over 29 years of experience in space power and electrical systems and in leading flight hardware 

development activities for over 16 robotic science missions. Dr. Day 

has also served as Chief Technologist for GSFC’s Engineering and 

Technology Directorate.

Dawn C. Emerson

NESC Chief Engineer

Ms. Dawn C. Emerson is the NESC's Chief Engineer at 

Glenn Research Center (GRC). Ms. Emerson came to 

the NESC from GRC, where she most recently served 

as the Deputy Project Manager during formulation of 

the Solar Electric Propulsion Flight Demonstration Project. Ms. Emerson has over 26 years of management and technical experience with 

NASA and private industry.

Walter C. Engelund

NESC Chief Engineer 

Mr. Walter C. Engelund is the NESC's Chief Engineer 

at Langley Research Center (LaRC). Mr. Engelund 

came to the NESC from LaRC, where he served as 

the Head of the Atmospheric Flight and Entry Systems 

Branch. Mr. Engelund has over 22 years of experience 

as a recognized expert in launch and entry vehicle aerodynamics, atmospheric flight dynamics, and hypersonic flight systems.

Steven J. Gentz

NESC Chief Engineer

Mr. Steven J. Gentz is the NESC's Chief Engineer at 

Marshall Space Flight Center (MSFC). Mr. Gentz was 

formerly a Principal Engineer with the NESC at Langley 

Research Center (LaRC). Mr. Gentz has over 28 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. 

R. Lloyd Keith

NESC Chief Engineer 

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

as support and backup for the Center Chief Engineer 

at the Jet Propulsion Laboratory (JPL). Mr. Keith has 

over 34 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. 

Nans Kunz

NESC Chief Engineer 

Mr. Nans Kunz is the NESC's Chief Engineer at Ames 

Research Center (ARC). Mr. Kunz came to the NESC 

from the Systems Engineering Division at ARC.

Mr. Kunz has over 33 years of engineering experience 

leading and managing NASA programs and projects, 

including serving as the Chief Engineer of the Stratospheric Observatory For Infrared Astronomy (SOFIA) Project.

2011 NESC TECHNICAL UPDATE

Biographies

59
Stephen A. Minute 

NESC Chief Engineer

Mr. Stephen A. Minute is the NESC’s 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 27 years of engineering and management experience in the Space Shuttle and International 

Space Station Programs. 

Michael D. Smiles

NESC Chief Engineer

Mr. Michael D. Smiles is the NESC’s Chief Engineer 

at Stennis Space Center (SSC). Mr. Smiles joined the 

NESC from SSC, where he served as the Safety and 

Mission Assurance (S&MA) Manager. Mr. Smiles has 

over 26 years of management and technical experience with NASA at SSC and Marshall Space Flight Center. 

Dr. James F. Stewart

NESC Chief Engineer

Dr. James F. Stewart is the NESC’s 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 45 years of management and technical experience leading missile 

and aircraft programs.

Timothy G. Trenkle

NESC Chief Engineer

Mr. Timothy G. Trenkle is the NESC’s Chief Engineer 

at Goddard Space Flight Center (GSFC). Mr. Trenkle 

joined the NESC from GSFC, where he has over 19 

years of technical experience serving as the technical lead for a number of flight programs and technical 

assignments, including serving as the Chief Engineer for the National 

Polar-Orbiting Operational Environmental Satellite System (NPOESS) 

Preparatory Project (NPP). 

NESC Chief Engineers Continued

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 35 years of experience on embedded software 

development.

Cornelius J. Dennehy

NASA Technical Fellow

Mr. Cornelius J. Dennehy is the NASA Technical Fellow for Guidance, Navigation, and Control (GNC) and 

is resident at Goddard Space Flight 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 31 years of experience in the architecture, design, development,

integration, and operation of GNC systems, and space platforms for 

communications, defense, remote sensing, and scientific mission

applications.

Roberto Garcia

NASA Technical Fellow

Mr. Roberto Garcia is the NASA Technical Fellow for 

Propulsion and is resident at Marshall Space Flight 

Center (MSFC). Mr. Garcia came to the NESC from the 

Solid Propulsion Systems Division, where he served as 

Division Chief. Mr. Garcia has over 20 years of experience in performing aerodynamic, hydrodynamic, and engine system design and analysis of rocket propulsion.

2011 NESC TECHNICAL UPDATE

Biographies

NASA Technical Fellows

60
2011 NESC TECHNICAL UPDATE

Biographies

NASA Technical Fellows Continued

Oscar Gonzalez

NASA Technical Fellow

Mr. Oscar Gonzalez is the NASA Technical Fellow for 

Avionics and is resident at Goddard Space Flight Center 

(GSFC). Mr. Gonzalez came to the NESC from GSFC, 

where he served as the International Space Station/Express Logistic Carrier (ELC) Avionics Systems Manager. Mr. Gonzalez 

has over 33 years of NASA and private industry experience where he 

has held a variety of critical leadership roles in power electronics, electrical systems, instrument systems, and avionics systems. 

Denney J. Keys

NASA Technical Fellow

Mr. Denney J. Keys is the NASA Technical Fellow for Electrical Power and is resident at Goddard 

Space Flight Center (GSFC). Mr. Keys served as 

the Lead Power Systems Engineer in the Power 

Systems Branch at GSFC before joining the NESC. 

Mr. Keys has over 31 years of private industry and NASA experience with

electrical power systems.

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 31 years of

engineering experience with expertise in stochastic structural dynamics, structural safety, and probabilistic engineering applications.

Daniel G. Murri

NASA Technical Fellow

Mr. Daniel G. Murri is the NASA Technical Fellow for 

Flight Mechanics and is resident at Langley Research 

Center (LaRC). Mr. Murri served as Head of the Flight 

Dynamics Branch at LaRC before joining the NESC. He 

has over 30 years of engineering experience conducting numerous 

wind-tunnel, simulation, flight-test, and theoretical studies in the exploration of new technology concepts and in support of aircraft development 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 

25 years of experience lecturing on Human Factors, and another 19 

years of experience in Human Factors applied to NASA programs.

Joseph W. Pellicciotti

NASA Technical Fellow

Mr. Joseph W. Pellicciotti is the NASA Technical Fellow 

for Mechanical Systems and is resident at Goddard 

Space Flight Center (GSFC). Mr. Pellicciotti served as 

the Chief Engineer for the GSFC Mechanical Systems 

Division before joining the NESC. Mr. Pellicciotti has over 23 years of 

combined private industry and NASA experience designing structure 

and mechanisms for commercial, military, and civil spacecraft.

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 27 years experience in 

the commercial nuclear power industry and over 18 years of experience 

in basic and applied materials research for several NASA programs.

Dr. William H. Prosser

NASA Technical Fellow

Dr. William H. 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 24 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 36 years of experience in structures, structural mechanics, and structural integrity. 

Steven L. Rickman

NASA Technical Fellow

Mr. Steven L. Rickman is the NASA Technical Fellow 

for Passive Thermal and is resident at Johnson Space 

Center (JSC). Mr. Rickman joined the NESC from 

JSC’s Thermal Design Branch, where he served as the 

Chief. Mr. Rickman has over 26 years of management and technical 

experience in passive thermal control.

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 44 years of life support and active thermal control systems experience during the Apollo, 

Space Shuttle, and Orbital Space Plane Programs.

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 33 years of experience 

in the aerospace industry with expertise in aeroelasticity and integrated 

aerodynamic analysis.

61
2011 NESC TECHNICAL UPDATE

Alumni

Frank H. Bauer

NESC Discipline Expert for Guidance Navigation and Control 

(2003–04) Left the NESC to 

become the Exploration Systems 

Mission Directorate Chief Engineer 

at NASA HQ and has since retired

J. Larry Crawford

NESC Deputy Director for 

Safety (2003–04) Left the NESC 

to become Director of Safety and 

Mission Assurance at the Kennedy 

Space Center (KSC) and has since 

retired

Dr. Charles J. Camarda

NESC Deputy Director for Advanced Projects (2006–09) Left 

the NESC to become Senior 

Advisor for Innovation in the Office 

of the Chief Engineer at NASA 

Headquarters

Kenneth D. Cameron

NESC Deputy Director for 

Safety (2005–08) Left the NESC 

to accept a position with Northrop 

Grumman

Steven F. Cash

NESC Chief Engineer at Marshall 

Space Flight Center (MSFC) 

(2005) Left the NESC to become 

the Manager, Shuttle Propulsion 

Office at MSFC

Derrick J. Cheston

NESC Chief Engineer at 

Glenn Research Center (GRC) 

(2003–07) Left the NESC to 

participate in the Senior Executive Service Candidate Development Program (SESCDP) and then 

returned to GRC as the Chief of 

the Mechanical and Fluid Systems 

Division

Mitchell L. Davis

NASA Technical Fellow for Avionics 

(2007–09) Left the NESC to become the Chief Avionics Systems 

Engineer in the Electrical Engineering Division at Goddard Space 

Flight Center

Dennis B. Dillman

NESC Chief Engineer at NASA 

Headquarters (HQ) (2005–08) Left 

the NESC to become an Engineer 

in the Science Mission Directorate 

at NASA HQ

Freddie Douglas, III

NESC Chief Engineer at Stennis Space Center (SSC) 

(2007–08) Left the NESC to 

become Manager, Office of Safety 

and Mission Assurance at SSC

Patricia L. Dunnington

Manager, Management and Technical Support Office (2006–08) 

Retired

Dr. Michael S. Freeman

NESC Chief Engineer at Ames Research Center (2003–04) Retired

T. Randy Galloway

NESC Chief Engineer at Stennis Space Center (SSC) 

(2003–04) Currently the Director of 

the Engineering and Test Directorate at SSC

Dr. Edward R. Generazio

NESC Discipline Expert for Nondestructive Evaluation (2003–05) Left 

the NESC to become a Senior 

Research Engineer, Research Directorate, Langley Research Center

Dr. Richard J. Gilbrech

NESC Deputy Director 

(2003–05) Currently the Deputy 

Center Director at Stennis Space 

Center

Michael Hagopian

NESC Chief Engineer at Goddard Space Flight Center (GSFC) 

(2003–07) Left the NESC to 

become the Chief Engineer in the 

Engineering Directorate at GSFC

David A. Hamilton

NESC Chief Engineer at Johnson 

Space Center (2003–07) Retired

Dr. Charles E. Harris

NESC Principal Engineer 

(2003–06) Currently the Director, Research Directorate, Langley 

Research Center

Dr. Steven A. Hawley

NESC Chief Astronaut 

(2003–04) Left the NESC to become the Director of Astromaterials 

Research and Exploration Science 

at Johnson Space Center and has 

since retired

Marc S. Hollander

Manager, Management and Technical Support Office (2005–06) Left 

the NESC to accept a position as 

the Associate Director for Management, National Institutes of Health

George D. Hopson

NASA Technical Fellow for Propulsion (2003–07) Retired

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 Johnson Space Center 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 and 

has since returned to ARC in the 

Office of the Chief Engineer

Julie A. Kramer White

NESC Discipline Expert for Mechanical Analysis (2003–06) Currently the Chief Engineer, MultiPurpose Crew Vehicle Program at 

Johnson Space Center

Steven G. Labbe

NESC Discipline Expert for Flight 

Sciences (2003–06) Currently 

the Chief, Aeroscience and Flight 

Mechanics Division at Johnson 

Space Center

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) 

Left the NESC to become the 

Senior Project Scientist for the 

Hubble Space Telescope at Goddard Space Flight Center and has 

since retired

Richard T. Manella

NESC Chief Engineer at NASA’s 

Glenn Research Center (GRC) 

(2009–10) Left the NESC to 

become Glenn Research Center’s 

Chief Engineer

John P. McManamen

NASA Technical Fellow for Mechanical Systems (2003–07) Currently the Deputy Manager, White 

Sands Test Facility

Brian K. Muirhead

NESC Chief Engineer at NASA’s 

Jet Propulsion Laboratory (JPL) 

(2005–07) Returned to his assignment as the Chief Engineer, Jet 

Propulsion Laboratory

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 the NESC's Management and Technical Support Office 

(2003–04) Left the NESC to 

become the Deputy Center Director 

at Ames Research Center and has 

since left NASA to accept a position at DoD

Dr. Tina L. Panontin

NESC Chief Engineer at Ames Research Center (2008–09) Returned 

to her assignment as the Ames 

Research Center Chief Engineer

Dr. Shamim A. Rahman

NESC Chief Engineer at Stennis Space Center (SSC) 

(2005–06) Left the NESC to 

become the Deputy Director of the 

Engineering and Test Directorate 

at SSC

Jerry L. Ross

NESC Chief Astronaut 

(2004–06) Returned to his assignment as Chief of the Vehicle 

Integration Test Office at Johnson 

Space Center

Dr. Charles F. Schafer

NESC Chief Engineer at Marshall 

Space Flight Center (2006–10)

Retired

Steven S. Scott

NESC Chief Engineer at Goddard Space Flight Center 

(2008–09) NESC Discipline Expert 

(now called NASA Technical Fellow) 

for Software (2003–05) Returned 

to his assignment as the Goddard 

Space Flight Center Chief Engineer 

Bryan K. Smith

NESC Chief Engineer at Glenn 

Research Center (2008–10) Left 

the NESC to serve as Chief of 

the Systems Engineering and 

Systems Analysis Division at Glenn 

Research Center

John E. Tinsley

NASA Headquarters Senior Safety 

and Mission Assurance Manager for NESC (2003–04) Left the 

NESC to become the Director of 

the Mission Support Division at 

NASA Headquarters and has since 

left NASA to accept a position with 

Northrop Grumman

Clayton P. Turner

NESC Chief Engineer at Langley 

Research Center (2008–09) Returned to his assignment as the 

Langley Research Center Chief 

Engineer

62
2011 NESC TECHNICAL UPDATE

Publications

1. Ares-I Upper Stage Design Study: The Effects of Buckling Knockdown Factors and Internal Pressure ........................ NASA/TM-2010-216848

2. Static Buckling Tests of Aerospace Vehicle Structures ................................................................................................... NASA/TM-2010-216849

3. Shell Buckling Knockdown Factor 1st Annual Workshop 14-15 October, 2009 Summary of Proceedings .................... NASA/TM-2010-216850

4. Design of Orthogrid Cylinder Test Articles For the Shell Buckling Knockdown Factor Assessment ............................... NASA/TM-2010-216866 ARL-TR-5122

5. Comparison of Requirements for Composite Structures for Aircraft and Space Applications ........................................ NASA/TM-2010-216869

6. Pre-Test Analysis Predictions for the Shell Buckling Knockdown Factor Checkout Tests TA01 and TA02 .................... NASA/TM-2011-216875 ARL-TR-5123

7. Longitudinal Weld Land Buckling in Compression-Loaded Orthogrid Cylinders ............................................................ NASA/TM-2010-216876 ARL-TR-5121

8. Guidance, Navigation & Control (GN&C) Design Overview and Flight Test Results From NASAs Max Launch

Abort System (MLAS) ....................................................................................................................................................... NASA/TM-2010-216877

9. Fracture Mechanics Analyses of the Slip-Side Joggle Regions of Wing-Leading-Edge Panels ..................................... NASA/TM-2011-216878

10. Probabilistic Design Case Study - NASA Engineering and Safety Center (NESC) Composite Crew Module (CCM) ...... NASA/TM-2011-217042/Volume I

11. Probabilistic Design Case Study - NASA Engineering and Safety Center (NESC) Composite Crew Module

(CCM) - Appendices ......................................................................................................................................................... NASA/TM-2011-217042/Volume II

12. Peer Review of Launch Environments .............................................................................................................................. NASA/TM-2011-217043

13. Lightweight Installable Micrometeoroid and Orbital Debris (MMOD) Shield Concepts for International

Space Station (ISS) Modules ............................................................................................................................................ NASA/TM-2011-217044/Volume I

14. Lightweight Installable Micrometeoroid and Orbital Debris (MMOD) Shield Concepts for International 

Space Station (ISS) Modules - Appendices ..................................................................................................................... NASA/TM-2011-217044/Volume II

15. Ares-V Design Study: The Effects of Buckling Knockdown Factors, Internal Pressure, and Materials ........................... NASA/TM-2011-217061

16. In-Suit Light Exercise (ISLE) Prebreathe Protocol Peer Review Assessment. ................................................................. NASA/TM-2011-217062/Volume I

17. In-Suit Light Exercise (ISLE) Prebreathe Protocol Peer Review Assessment - Appendices ............................................ NASA/TM-2011-217062/Volume II

18. Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis, Phase 2 Results ................................... NASA/TM-2011-217063

19. International Space Station (ISS) Solar Array Wing (SAW) Lessons Learned .................................................................. NASA/TM-2011-217064/Volume I

20. International Space Station (ISS) Solar Array Wing (SAW) Lessons Learned - Appendices ............................................ NASA/TM-2011-217064/Volume II

21. Performance Characterization of Loctite 242 and 271 Liquid Locking Compounds (LLCs) as a Secondary

Locking Feature for International Space Station (ISS) Fasteners ..................................................................................... NASA/TM-2011-217068

22. Independent Review of U.S. and Russian Probabilistic Risk Assessments for the International Space

Station Mini Research Module #2 Micrometeoroid and Orbital Debris Risk .................................................................... NASA/TM-2011-217070

23. Recommendations for Safe Separation Distances From the Kennedy Space Center (KSC) Vehicle Assembly 

Building (VAB) Using a Heat-Flux-Based Analytical Approach - Abridged ...................................................................... NASA/TM-2011-217071

24. Space Shuttle Program (SSP) Orbiter Main Propulsion System (MPS) Gaseous Hydrogen (GH2) Flow Control

Valve (FCV) Poppet Eddy Current (EC) Inspection Probability of Detection (POD) Study ............................................... NASA/TM-2011-217072/Volume I

25. Space Shuttle Program (SSP) Orbiter Main Propulsion System (MPS) Gaseous Hydrogen (GH2) Flow Control

Valve (FCV) Poppet Eddy Current (EC) Inspection Probability of Detection (POD) Study - Appendices ......................... NASA/TM-2011-217072/Volume II

26. Pre-Test Analysis for 45-Percent-Scale Ares-I Liquid Hydrogen Barrel Test Articles ..................................................... NASA/TM-2011-217073 ARL-TR-5486

27. Design of the Space Shuttle External-Tank-Derived Test Articles for the Shell Buckling

Knockdown Factor Project ............................................................................................................................................... NASA/TM-2011-217074 ARL-TR-5485

28. Independent Review of the Constellation Program (CxP) Ares-I Launch Vehicle Control Sensitivity to Orion 

Service Module (SM) Tank Slosh Dynamics ..................................................................................................................... NASA/TM-2011-217075

29. Recent Experiences of the NASA Engineering and Safety Center (NESC) Guidance Navigation and Control 

(GN&C) Technical Discipline Team (TDT) ......................................................................................................................... NASA/TM-2011-217083

30. Flight Simulation Model Exchange ................................................................................................................................... NASA/TM-2011-217085/Volume I

31. Flight Simulation Model Exchange - Appendices ............................................................................................................ NASA/TM-2011-217085/Volume II

32. Max Launch Abort System (MLAS) Landing Parachute Demonstrator (LPD) Drop Test ................................................. NASA/TM-2011-217086

33. A Summary of the Rendezvous, Proximity Operations, Docking, and Undocking (RPODU) Lessons Learned from

the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) Demonstration System Mission ........ NASA/TM-2011-217088

34. Readiness for First Crewed Flight .................................................................................................................................... NASA/TM-2011-217089

35. Development and Certification of Ultrasonic Background Noise Test (UBNT) System for use on the

International Space Station (ISS) ...................................................................................................................................... NASA/TM-2011-217151

36. Orion Alternate Launch Abort System (ALAS) Follow On Technical Investigations Assessment .................................... NASA/TM-2011-217155/Volume I

37. Orion Alternate Launch Abort System (ALAS) Follow On Technical Investigations Assessment - Appendices .............. NASA/TM-2011-217155/Volume II

38. A-3 Test Stand Structural Dynamics Analysis .................................................................................................................. NASA/TM-2011-217160

39. Assessment of Fatigue-Based Reliability Computations for Space Shuttle Program (SSP) Solid Rocket

Booster (SRB) Integrated Electronic Assembly (IEA) Power Buss Isolation Supply (PBIS) Transformers ....................... NASA/TM-2011-217165

40. Structural Assessment of the International Space Station (ISS) European-Manufactured Modules ............................... NASA/TM-2011-217172/Volume I

41. Assessment of NASA’s Approach to Space Transportation System (STS)-135 With Soyuz Crew Rescue .................... NASA/TM-2011-217175

continued on next page

NESC/NASA Published Technical Memoranda

63
2011 NESC TECHNICAL UPDATE

Publications

42. Orion Flight Test-1 (OFT-1) Radiometer Feasibility Study (Phase I).................................................................................. NASA/TM-2011-217180

43. Comparison of the Booster Interface Temperature in Stainless Steel (SS) V-Channel versus the Aluminum (Al)

Y-Channel Primer Chamber Assemblies (PCAs)............................................................................................................... NASA/TM-2011-217182/Volume I

44. Comparison of the Booster Interface Temperature in Stainless Steel (SS) V-Channel versus the Aluminum (Al)

Y-Channel Primer Chamber Assemblies (PCAs) Appendices .......................................................................................... NASA/TM-2011-217182/Volume II

45. Independent Review of the Constellation Program (CxP) Ares-I Launch Vehicle Control Sensitivity to Orion Service

Module (SM) Tank Slosh Dynamics V2.0 ......................................................................................................................... NASA/TM-2011-217183

46. Composite Crew Module: Primary Structure ................................................................................................................... NASA/TM-2011-217185

47. Composite Crew Module: Design .................................................................................................................................... NASA/TM-2011-217186

48. Composite Crew Module: Materials and Processes ........................................................................................................ NASA/TM-2011-217187

49. Composite Crew Module: Analysis .................................................................................................................................. NASA/TM-2011-217188

50. Composite Crew Module: Manufacturing ........................................................................................................................ NASA/TM-2011-217189

51. Composite Crew Module: Test ......................................................................................................................................... NASA/TM-2011-217190

52. Composite Crew Module: Nondestructive Evaluation Report ......................................................................................... NASA/TM-2011-217191

1. The First Flight Decision for New Human Spacecraft Vehicles - A 

General Approach. Presented at 62nd International Astronautical Congress, 

October 3-7, 2011, Cape Town, South Africa.

2. Modeling, Analysis and Simulation Approaches Used in Development 

of the National Aeronautics and Space Administration Max Launch Abort 

System. Presented at 26th Aerospace Testing Seminar, March 29-31, 

2011, Manhattan Beach, California.

3. A Review of the NASA MLAS Flight Demonstration. Presented at 21st 

AIAA Aerodynamic Decelerator Systems Technology Conference and 

Seminar, May 23-26, 2011, Dublin, Ireland. 

4. Testing Strategies and Methodologies for the Max Launch Abort System. Presented at 26th Aerospace Testing Seminar, March 29-31, 2011, 

Manhattan Beach, California.

5. Overview of the NESC Passive Thermal Technical Discipline Team. 

Presented at 2011 Thermal and Fluids Analysis Workshop, August 15-19, 

2011, Newport News, Virginia. 

6. Introduction to On-Orbit Thermal Environments. Presented at 2011 

Thermal and Fluids Analysis Workshop, August 15-19, 2011, Newport 

News, Virginia. 

7. Ensuring Durability and Damage Tolerance in Aerospace Structures. 

Presented at ICCES ‘11 - International Conference on Computational and 

Experimental Engineering and Sciences, April 18-21, 2011, Nanjing, China.

8. An Improved Method of Structural-Borne Random Vibration Mass 

Attenuation. Presented at 162nd Meeting of the Acoustical Society of 

America, October 31-November 4, 2011, San Diego, California. 

9. Special Topics in Random Vibrations. Presented at Spacecraft and 

Launch Vehicle Dynamic Environment Workshop, June 7-9, 2011, El Segundo, California. 

10. The NASA Engineering and Safety Center (NESC): Shock and Vibration 

Training Program. Presented at Spacecraft and Launch Vehicle Dynamic 

Environment Workshop, June 7-9, 2011, El Segundo, California. 

11. Wilkinson Microwave Anisotropy Probe (WMAP) Nickel-Hydrogen 

(NiH2) Battery Anomaly Investigation. Presented at 29th Annual Space 

Power Workshop, April 18-21, 2011, Los Angeles, California. 

12. Progress in Quantifying Uncertainty for Vibroacoustic Environments. 

Presented at Spacecraft and Launch Vehicle Dynamic Environment Workshop, June 7-9, 2011, El Segundo, California. 

13. Spacecraft Testing Programs: Adding Value to the Systems Engineering Process. Presented at 26th Aerospace Testing Seminar, March 29-31, 

2011, Manhattan Beach, California. 

14. Hutchings, A.; Shah, P.; Streett, C. L.; and Larsen, C. E.: Validation of Methods to Predict Vibration of a Panel in the Near Field of a Hot 

Supersonic Rocket Plume. Presented at 17th AIAA/CEAS Aeroacoustics 

Conference, June 6-8, 2011, Portland, Oregon. 

15. Hutchings, A.; and Shah, P.: Validation of Methods to Predict Vibration 

of a Panel in the Near Field of a Hot Supersonic Rocket Plume. Presented 

at Spacecraft and Launch Vehicle Dynamic Environment Workshop, June 

7-9, 2011, El Segundo, California. 

16. Estimating Modal Damping From Operational Tests. Presented at 

Spacecraft and Launch Vehicle Dynamic Environment Workshop, June 7-9, 

2011, El Segundo, California. 

17. Human Factors Throughout the Life Cycle: Lessons Learned From 

the Shuttle Program. 5th International Association for the Advancement of 

Space Safety Conference, October 17-19, 2011, Versailles, France.

18. Human Factors Throughout the Life Cycle: Lessons Learned From the 

Shuttle Program - Manufacturing. 5th International Association for the Advancement of Space Safety Conference, October 17-19, 2011, Versailles, 

France.

19. Grid Fin Stabilization of the Orion Launch Abort Vehicle. 29th AIAA Applied Aerodynamics Conference, June 27-30, 2011, Honolulu, Hawaii.

20. High-Order Methods in NASA’s Next Generation of Computational 

Fluid Dynamics Tools. European Workshop on High Order Numerical Methods for Evolutionary PDEs: Theory and Applications, April 11-15, 2011, 

Trento, Italy.

NESC/NASA Published Technical Memoranda ... continued

Presented Papers

64
The NESC is proud to have provided support to 21 

Space Shuttle missions since STS-114 Return to Flight. 

We salute the men and women of the Space Shuttle 

Program for 30 years of dedication and achievement.
National Aeronautics and Space Administration

Langley Research Center 

Hampton, VA 23681

www.nasa.gov

NP-2011-11-351-LaRC