Mahesh Singh                                 Greater Noida, U.P  
Data Analyst |maheshsinghkoyad1234 @gmail.com| LinkedIn                                   8218160792  
Enthusiastic Data Analyst in pursuit of a career, I am driven by a passion for impactful data -driven decision -
making. Proficient in Power BI, Excel, and SQL tools, I bring dedication and curiosity to the field. Despite my 
limited professional experience, I  am eager to contribute and learn, showcasing a commitment to excel in this 
dynamic role.  
Certifications  
● Excel – Coursera (Intermediate)  
-VLookup , HLookup  
-Power Queary  
-Data Validation  
-Pivot Table s 
-Index & Match  
-Text Functions  
 
Skills  
● Excel  
● Power BI  
● PowerPoint  
  
Education  
DBRAU          - B.Sc.  - 2022  
State Board  -12th    -2019  
 
Soft skills  
● Problem solving skills  
● Strong communication and 
influencing skills  
● Commitment to work and self -
motivation  
● Strong strategic and 
organizational thinking skills  
 
 Projects  
1. Accenture Virtual Internship :  
Sentimental analysis of reaction scores:  
Summary : 
Prepare a PowerPoint analysis for SocialBuzz, a social networking site, with 
the goal of turning static data into a dynamic report. The aim is to uncover 
the top 5 categories based on customer reviews, facilitating strategic 
decision -making for the advancement of the platform.  
 
Actions : 
1. We begin by acquiring the essential data from their site.  
2. Afterward, we conduct data cleaning and mode lling through Excel.  
3. Next, we anal yse the data, implementing top N filters to derive results.  
4. Finally, we share our insights based on the conducted analysis.  
 
Result : 
The PowerPoint presentation provided valuable insights for decision -making 
to the executives, enabling them to implement necessary changes on their 
platform for improvement.  
 
Insights : 
1. Based on our analysis, we pinpointed the top 5 categories.  
2. The animal category took the lead with a score of 74965.  
3. Animals contributed to 8% of the total reaction scores.  
4. Food landed in the bottom position within the top 5 categories with score 
of 66676  
 
2. Tata Virtual Internship  : 
Dynamic Transaction Analytics: Power BI Transformation  
Summary : 
Executed a Power BI analysis to transform static monthly reports to a 
dynamic, live view of transaction data. The aim was to aid decision - asking 
on headquarters' location and refine product marketing strategies based on 
evolving customer expectations.  
 
Actions : 
1. Initiated analysis with preliminary inquiries.  
2. Imported source data from data. World in CSV format.  
3. Conducted in -depth analysis using calculated fields, LOD expressions, 
parameters, and Top N filters.  
4. Developed interactive Power BI dashboard with focus on KPIs, regional 
sales, profit, and product insights.  
 
Result:  
The Power BI dashboard enables proactive decision -making  on location , 
offering a dynamic view of transaction data. Executives can now stay ahead 
of trends and make informed choices regarding headquarter s location.  
 
Top 5 Insights:  
1. Technology category dominates with 80% of Top 10 Selling Products by 
Profit.  
2. "Canon image CLASS 2200 Advanced Copier" contributes 2.68% to total 
sales.  
3. West Region outperforms others, generating 3% more profit.  
4. Bottom 10 Products in Sales belong to the Office Supplies category, 
indicating a seasonal trend.  
5. Standard class shipping accounts for 59% of all sales, highlighting price 
sensitivity over faster delivery.  
 
Next Steps : 
1. Implement action filters affecting specific visualizations.  
2. Introduce a reset button for filters.  
3. Create hidden filters with a pop -up icon for user -friendly navigation.  
4. Future revisions and improvements to be explored after gaining more PBI 
expertise through additional projects.  National Aeronautics and  
 Space Administration
NASA  
SYSTEMS ENGINEERING  
HANDBOOK
design
test
integrate
fly
www.nasa.govNASA SP-2016-6105 Rev2 supersedes SP-2007-6105 Rev 1 dated December, 2007.
Cover photos:  Top left:  In this photo, engineers led by researcher Greg Gatlin have sprayed fluorescent oil on a 5.8 percent scale 
model of a futuristic hybrid wing body during tests in the 14- by 22-Foot Subsonic Wind Tunnel at NASA’s Langley Research Center 
in Hampton, VA. The oil helps researchers “see” the flow patterns when air passes over and around the model. (NASA Langley/
Preston Martin) Top right:  Water impact test of a test version of the Orion spacecraft took place on August 24, 2016, at NASA 
Langley Research Center (NASA) Bottom left:  two test mirror segments are placed onto the support structure that will hold them. 
(NASA/Chris Gunn) Bottom right: This self-portrait of NASA’s Curiosity Mars rover shows the vehicle at the “Mojave” site, where its 
drill collected the mission’s second taste of Mount Sharp. (NASA/JPL-Caltech/MSSS)
Comments, questions, and suggestions  regarding this document can be sent to:
Steven R. Hirshorn
Chief Engineer, Aeronautics Research Mission Directorate (ARMD)
Office of the Chief Engineer
NASA Headquarters, Room 6D37
300 E St SW
Washington, DC 20546-0001
202-358-0775
steven.r.hirshorn@nasa.goviii
NASA SYSTEMS ENGINEERING HANDBOOKTable of Contents
Preface                                        viii
Acknowledgments                              ix
1.0 Introduction  1
1.1 Purpose    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 1
1.2 Scope and Depth    .  .  .  .  .  .  .  .  .  .  . 1
2.0 Fundamentals of Systems Engineering  3
2.1 The Common Technical Processes  
and the SE Engine   .  .  .  .  .  .  .  .  .  .  . 5
2.2 An Overview of the SE Engine by  
Project Phase    .  .  .  .  .  .  .  .  .  .  .  .  . 8
2.3 Example of Using the SE Engine   .  .  .  .  10
2.4 Distinctions between Product  
Verification and Product Validation   .  .  .  11
2.5 Cost Effectiveness Considerations   .  .  .  11
2.6 Human Systems Integration (HSI)  
in the SE Process    .  .  .  .  .  .  .  .  .  .  . 12
2.7 Competency Model for  
Systems Engineers   .  .  .  .  .  .  .  .  .  .  .  13
3.0 NASA Program/Project Life Cycle  17
3.1 Program Formulation   .  .  .  .  .  .  .  .  .  . 20
3.2 Program Implementation   .  .  .  .  .  .  .  . 20
3.3 Project Pre-Phase A: Concept Studies   . 21
3.4 Project Phase A: Concept and  
Technology Development   .  .  .  .  .  .  .  . 23
3.5 Project Phase B: Preliminary Design  
and Technology Completion   .  .  .  .  .  .  25
3.6 Project Phase C: Final Design and 
Fabrication   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  27
3.7 Project Phase D: System Assembly, Integration and Test, Launch
  .  .  .  .  .  . 29
3.8 Project Phase E: Operations  
and Sustainment   .  .  .  .  .  .  .  .  .  .  .  .  31
3.9 Project Phase F: Closeout    .  .  .  .  .  .  . 313.10 Funding: The Budget Cycle   .  .  .  .  .  .  . 33
3.11 Tailoring and Customization of  
NPR 7123  .1 Req uirements   .  .  .  .  .  .  . 34
3.11.1  Introduction  34
3.11.2  Criteria for Tailoring  34
3.11.3   Tailoring SE NPR Requirements  
Using the Compliance Matrix  35
3.11.4   Ways to Tailor a SE Requirement  36
3.11.5   Examples of Tailoring and 
Customization  37
3.11.6   Approvals for Tailoring  40
4.0 System Design Processes  43
4.1  Stakeholder Expectations Definition    .  .45
4.1.1  Process Description  45
4.1.2   Stakeholder Expectations Definition 
Guidance  53
4.2 Technical Requirements Definition   .  .  . 54
4.2.1  Process Description  54
4.2.2   Technical Requirements Definition 
Guidance  62
4.3 Logical Decomposition   .  .  .  .  .  .  .  .  . 62
4.3.1  Process Description  62
4.3.2   Logical Decomposition Guidance  65
4.4 Design Solution Definition    .  .  .  .  .  .  .65
4.4.1  Process Description  66
4.4.2   Design Solution Definition Guidance  76
5.0 Product Realization  77
5.1 Product Implementation    .  .  .  .  .  .  .  . 78
5.1.1  Process Description  79
5.1.2   Product Implementation Guidance  83
5.2 Product Integration   .  .  .  .  .  .  .  .  .  .  . 83
5.2.1  Process Description  85
5.2.2  Product Integration Guidance  88
5.3 Product Verification   .  .  .  .  .  .  .  .  .  .  . 88iv
5.3.1  Process Description  89
5.3.2  Product Verification Guidance  99
5.4 Product Validation    .  .  .  .  .  .  .  .  .  .  .99
5.4.1  Process Description  99
5.4.2  Product Validation Guidance  106
5.5 Product Transition    .  .  .  .  .  .  .  .  .  . 106
5.5.1  Process Description  106
5.5.2  Product Transition Guidance  11 2
6.0 Crosscutting Technical Management  11 3
6.1 Technical Planning   .  .  .  .  .  .  .  .  .  . 113 
6.1.1  Process Description  11 4
6.1.2  Technical Planning Guidance  13 0
6.2 Requirements Management    .  .  .  .  . 130
6.2.1  Process Description  13 1
6.2.2   Requirements Management 
Guidance  1 35
6.3 Interface Management   .  .  .  .  .  .  .  . 135
6.3.1  Process Description  13 6
6.3.2  Interface Management Guidance  13 8
6.4 Technical Risk Management   .  .  .  .  . 138
6.4.1   Risk Management Process 
Description  1 41
6.4.2   Risk Management Process 
Guidance  1 43
6.5 Configuration Management   .  .  .  .  .  . 143
6.5.1  Process Description  14 4
6.5.2  CM Guidance  15 0
6.6 Technical Data Management   .  .  .  .  . 151
6.6.1  Process Description  15 1
6.6.2   Technical Data Management 
Guidance  155
6.7 Technical Assessment   .  .  .  .  .  .  .  . 155
6.7.1  Process Description  15 7
6.7.2  Technical Assessment Guidance  16 0
6.8 Decision Analysis   .  .  .  .  .  .  .  .  .  .  . 160
6.8.1  Process Description  164
6.8.2  Decision Analysis Guidance  17 0Appendix A  Acronyms    .  .  .  .  .  .  .  .  .  .  .  .  .  . 173
Appendix B  Glossary   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 176

Appendix C   How to Write a Good Requirement— 
Checklist   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 197
Appendix D  Requirements Verification Matrix   .  .  . 201
Appendix E   Creating the Validation Plan with a 
Validation Requirements Matrix   .  .  .  .  203
Appendix F  Functional, Timing, and State Analysis  205
Appendix G  Technology Assessment/Insertion   .  . 206
Appendix H  Integration Plan Outline   .  .  .  .  .  .  .  . 214
Appendix I  Verification and Validation Plan Outline  216
Appendix J  SEMP Content Outline   .  .  .  .  .  .  .  . 223
Appendix K  Technical Plans   .  .  .  .  .  .  .  .  .  .  .  .  235
Appendix L   Interface Requirements Document  
Outline   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  236
Appendix M  CM Plan Outline    .  .  .  .  .  .  .  .  .  .  . 239
Appendix N   Guidance on Technical Peer  
Reviews/Inspections   .  .  .  .  .  .  .  .  . 240
Appendix O  Reserved   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 241
Appendix P  SOW Review Checklist   .  .  .  .  .  .  .  . 242
Appendix Q  Reserved   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 243
Appendix R  HSI Plan Content Outline   .  .  .  .  .  .  . 244
Appendix S   Concept of Operations  
Annotated Outline    .  .  .  .  .  .  .  .  .  . 251
Appendix T  Systems Engineering in Phase E   .  .  . 254
References Cited                             260
Bibliography                                  270v
NASA SYSTEMS ENGINEERING HANDBOOKTable of Figures
Figure 2.0-1  SE in Context of Overall Project 
Management   .  .  .  .  .  .  .  .  .  .  .  .  . 5
Figure 2.1-1  The Systems Engineering Engine  
(NPR 7123  . 1)   .  .  .  .  .  .  .  .  .  .  .  .  . 6
Figure 2.2-1  Miniature Version of the Poster-Size NASA Project Life Cycle Process 
Flow for Flight and Ground Systems 
Accompanying this Handbook
   .  .  .  . 8
Figure 2.5-1  Life-Cycle Cost Impacts from Early Phase Decision-Making
  .  .  .  .  .  .  .  .  13
Figure 3.0-1  NASA Space Flight Project Life Cycle 
from NPR 7120  . 5E   .  .  .  .  .  .  .  .  .  . 18
Figure 3.11-1  Notional Space Flight Products  
Tailoring Process   .  .  .  .  .  .  .  .  .  .  . 36
Figure 4.0 -1 Interrelationships among the System Design Processes
  .  .  .  .  .  .  .  .  .  .  . 44
Figure 4.1 -1 Stakeholder Expectations Definition Process
  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 46
Figure 4.1 -2 Information Flow for Stakeholder Expectations
  .  .  .  .  .  .  .  .  .  .  .  .  . 48
Figure 4.1 -3 Example of a Lunar Sortie DRM Early in the Life Cycle
  .  .  .  .  .  .  .  .  .  .  .  .  .  51
Figure 4.2 -1 Technical Requirements Definition Process
  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 55
Figure 4.2-2  Flow, Type and Ownership of Requirements
  .  .  .  .  .  .  .  .  .  .  .  .  .  57
Figure 4.2 -3 The Flowdown of Requirements   .  .  .  . 58
Figure 4.3 -1 Logical Decomposition Process   .  .  .  . 63
Figure 4.4 -1 Design Solution Definition Process   .  .66
Figure 4.4 -2 The Doctrine of Successive  
Refinement   .  .  .  .  .  .  .  .  .  .  .  .  .  .  67
Figure 4.4 -3 A Quantitative Objective Function, Dependent on Life Cycle Cost and  
All Aspects of Effectiveness
  .  .  .  .  .  .  71
Figure 5.0-1  Product Realization   .  .  .  .  .  .  .  .  .  .  78
Figure 5.1-1  Product Implementation Process   .  .  .  79Figure 5.2-1  Product Integration Process    .  .  .  .  .86
Figure 5.3-1  Product Verification Process    .  .  .  .  . 91
Figure 5.3-2  Example of End-to-End Data Flow  
for a Scientific Satellite Mission   .  .  .  . 96
Figure 5.4-1  Product Validation Process   .  .  .  .  . 100
Figure 5.5-1  Product Transition Process   .  .  .  .  . 107
Figure 6.1 -1 Technical Planning Process   .  .  .  .  . 115
Figure 6.2 -1 Requirements Management Process  131
Figure 6.3 -1 Interface Management Process   .  .  . 136
Figure 6.4-1  Risk Scenario Development   .  .  .  .  . 139
Figure 6.4-2  Risk as an Aggregate Set of  
Risk Triplets   .  .  .  .  .  .  .  .  .  .  .  .  . 139
Figure 6.4-3  Risk Management Process   .  .  .  .  . 141
Figure 6.4-4  Risk Management as the Interaction  
of Risk-Informed Decision Making  
and Continuous Risk Management   . 142
Figure 6.5 -1 Configuration Management Process  145
Figure 6.5 -2 Five Elements of Configuration Management
  .  .  .  .  .  .  .  .  .  .  .  . 145
Figure 6.5 -3 Evolution of Technical Baseline   .  .  . 147
Figure 6.5 -4 Typical Change Control Process    .  . 148
Figure 6.6 -1 Technical Data Management  
Process   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 151
Figure 6.7 -1 Technical Assessment Process   .  .  . 158
Figure 6.7 -2 Planning and Status  
Reporting Feedback Loop    .  .  .  .  . 159
Figure 6.8 -1 Decision Analysis Process    .  .  .  .  . 165
Figure 6.8-2  Risk Analysis of Decision Alternatives  166
Figure G.1-1  PBS Example   .  .  .  .  .  .  .  .  .  .  .  .  208
Figure G.3-1  Technology Assessment Process   .  . 209
Figure G.3-2  Architectural Studies and  
Technology Development   .  .  .  .  .  . 210
Figure G.4-1  Technology Readiness Levels   .  .  .  . 211
Figure G.4-2  TMA Thought Process    .  .  .  .  .  .  . 212
Figure G.4-3  TRL Assessment Matrix   .  .  .  .  .  .  . 213vi
NASA SYSTEMS ENGINEERING HANDBOOKTable of Tables
Table 2.1-1  Alignment of the 17 SE Processes to 
AS9100   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 7
Table 2.2-1  Project Life Cycle Phases   .  .  .  .  .  .  . 9
Table 2.7-1  NASA System Engineering  
Competency Model   .  .  .  .  .  .  .  .  .  .  14
Table 3.0-1  SE Product Maturity from NPR 7123  .1 19
Table 3.11-1  Example of Program/Project Types   .  .38
Table 3.11-2  Example of Tailoring NPR 7120  .5  
Required Project Products    .  .  .  .  .  .39
Table 3.11-3  Example Use of a Compliance Matrix   . 41
Table 4.1-1  Stakeholder Identification  
throughout the Life Cycle   .  .  .  .  .  .  .  47
Table 4.2-1  Benefits of Well-Written Requirements  59
Table 4.2 -2 Requirements Metadata    .  .  .  .  .  .  .59
Table 5.3-1  Example information in Verification Procedures and Reports
   .  .  .  .  .  .  .94
Table 6.1-1  Example Engineering Team  
Disciplines in Pre-Phase A for  
Robotic Infrared Observatory   .  .  .  . 118Table 6.1-2  Examples of Types of Facilities to Consider during Planning
  .  .  .  .  .  . 120
Table 6.6 -1 Technical Data Tasks   .  .  .  .  .  .  .  . 156
Table 6.7-1  Purpose and Results for Life-Cycle Reviews for Spaceflight Projects
   .  . 161
Table 6.8 -1 Typical Information to Capture in a Decision Report
  .  .  .  .  .  .  .  .  .  .  . 171
Table D-1  Requirements Verification Matrix    .  . 202
Table E-1  Validation Requirements Matrix   .  .  .  204
Table G.1-1  Products Provided by the TA as a Function of Program/Project Phase
  . 207
Table J-1  Guidance on SEMP Content per  
Life-Cycle Phase    .  .  .  .  .  .  .  .  .  . 233
Table K-1  Example of Expected Maturity of  
Key Technical Plans   .  .  .  .  .  .  .  .  .  235
Table R.2-1  HSI Activity, Product, or Risk Mitigation by Program/Project Phase
   .  .  .  .  . 250vii
NASA SYSTEMS ENGINEERING HANDBOOKTable of Boxes
The Systems Engineer’s Dilemma    .  .  .  .  .  .  .  .  .  . 12
Space Flight Program Formulation   .  .  .  .  .  .  .  .  .  . 20
Space Flight Program Implementation   .  .  .  .  .  .  .  .  21
Space Flight Pre -P hase A: Concept Studies   .  .  .  .  . 22
Space Flight Phase A:  
Concept and Technology Development    .  .  .  .  .  .  . 24
Space Flight Phase B:  
Preliminary Design and Technology Completion   .  .  . 26
Space Flight Phase C: Final Design and Fabrication    .28
Space Flight Phase D:  
System Assembly, Integration and Test, Launch   .  .  . 30
Space Flight Phase E: Operations and Sustainment   .32
Phase F: Closeout   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 33
System Design Keys   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 44
Concept of Operations vs  .  Operations Concept    .  .  . 51
Example of Functional and Performance  
Requirements    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .56
Rationale   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 60
Product Realization Keys   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  78Differences between Verification and  
Validation Testing   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 89
Differences between Verification, Qualification, 
Acceptance and Certification   .  .  .  .  .  .  .  .  .  .  .  .  . 90
Methods of Verification   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 93
Methods of Validation    .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 101
Crosscutting Technical Management Keys   .  .  .  .  . 114
Types of Hardware   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 124
Environments   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 127
Definitions    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 130
Types of Configuration Management Changes   .  .  . 149
Data Collection Checklist   .  .  .  .  .  .  .  .  .  .  .  .  .  . 155

HSI Relevance   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 246
HSI Strategy   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 246
HSI Domains   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 247
HSI Requirements   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 247
HSI Implementation    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 249
HSI Plan Updates    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 250viii
NASA SYSTEMS ENGINEERING HANDBOOKPreface
Since the initial writing of NASA/SP-6105 in 1995 
and the following revision (Rev 1) in 2007, systems 
engineering as a discipline at the National Aeronautics 
and Space Administration (NASA) has undergone 
rapid and continued evolution. Changes include 
using Model-Based Systems Engineering to improve 
development and delivery of products, and accommo -
dating updates to NASA Procedural Requirements 
(NPR) 7123.1. Lessons learned on systems engi -
neering were documented in reports such as those 
by the NASA Integrated Action Team (NIAT), the 
Columbia Accident Investigation Board (CAIB), and 
the follow-on Diaz Report. Other lessons learned were 
garnered from the robotic missions such as Genesis 
and the Mars Reconnaissance Orbiter as well as from 
mishaps from ground operations and the commercial 
space flight industry. Out of these reports came the 
NASA Office of the Chief Engineer (OCE) initia -
tive to improve the overall Agency systems engineer -
ing infrastructure and capability for the efficient and 
effective engineering of NASA systems, to produce 
quality products, and to achieve mission success. This 
handbook update is a part of that OCE-sponsored 
Agency-wide systems engineering initiative.
In 1995, SP-6105 was initially published to bring the 
fundamental concepts and techniques of systems engi -
neering to NASA personnel in a way that recognized 
the nature of NASA systems and the NASA environ -
ment. This revision (Rev 2) of SP-6105 maintains that 
original philosophy while updating the Agency’s sys -
tems engineering body of knowledge, providing guid -
ance for insight into current best Agency practices, 
and maintaining the alignment of the handbook with 
the Agency’s systems engineering policy.The update of this handbook continues the methodol -
ogy of the previous revision: a top-down compatibility 
with higher level Agency policy and a bottom-up infu -
sion of guidance from the NASA practitioners in the 
field. This approach provides the opportunity to obtain 
best practices from across NASA and bridge the infor -
mation to the established NASA systems engineering 
processes and to communicate principles of good prac -
tice as well as alternative approaches rather than spec -
ify a particular way to accomplish a task. The result 
embodied in this handbook is a top-level implemen -
tation approach on the practice of systems engineer -
ing unique to NASA. Material used for updating this 
handbook has been drawn from many sources, includ -
ing NPRs, Center systems engineering handbooks and 
processes, other Agency best practices, and external 
systems engineering textbooks and guides.
This handbook consists of six chapters: (1) an intro -
duction, (2) a systems engineering fundamentals dis -
cussion, (3) the NASA program/project life cycles, 
(4) systems engineering processes to get from a con -
cept to a design, (5) systems engineering processes to 
get from a design to a final product, and (6) crosscut -
ting management processes in systems engineering. 
The chapters are supplemented by appendices that 
provide outlines, examples, and further information 
to illustrate topics in the chapters. The handbook 
makes extensive use of boxes and figures to define, 
refine, illustrate, and extend concepts in the chapters.
Finally, it should be noted that this handbook provides 
top-level guidance for good systems engineering prac -
tices; it is not intended in any way to be a directive.
NASA/SP-2016-6105 Rev2 supersedes SP-2007-6105 Rev 1 
dated December, 2007.ix
NASA SYSTEMS ENGINEERING HANDBOOKAcknowledgments
The following individuals are recognized as contrib -
uting practitioners to the content of this expanded 
guidance:
Alexander, Michael, NASA/Langley Research Center
Allen, Martha, NASA/Marshall Space Flight Center
Baumann, Ethan, NASA/Armstrong Flight Research Center
Bixby, CJ, NASA/Armstrong Flight Research Center
Boland, Brian, NASA/Langley Research Center
Brady, Timothy, NASA/NASA Engineering and Safety Center
Bromley, Linda, NASA/Headquarters/Bromley SE Consulting
Brown, Mark, NASA/Jet Propulsion Laboratory
Brumfield, Mark, NASA/Goddard Space Flight Center
Campbell, Paul, NASA/Johnson Space Center
Carek, David, NASA/Glenn Research Center
Cox, Renee, NASA/Marshall Space Flight Center
Crable, Vicki, NASA/Glenn Research Center
Crocker, Alan, NASA/Ames Research Center
DeLoof, Richard, NASA/Glenn Research Center
Demo, Andrew/Ames Research Center
Dezfuli, Homayoon, NASA/HQ
Diehl, Roger, NASA/Jet Propulsion Laboratory
DiPietro, David, NASA/Goddard Space Flight Center
Doehne, Thomas, NASA/Glenn Research Center
Duarte, Alberto, NASA/Marshall Space Flight Center
Durham, David, NASA/Jet Propulsion Laboratory
Epps, Amy, NASA/Marshall Space Flight Center
Fashimpaur, Karen, Vantage Partners
Feikema, Douglas, NASA/Glenn Research Center
Fitts, David, NASA/Johnson Space Flight Center
Foster, Michele, NASA/Marshall Space Flight Center
Fuller, David, NASA/Glenn Research Center
Gati, Frank, NASA/Glenn Research Center
Gefert, Leon, NASA/Glenn Research Center
Ghassemieh, Shakib, NASA/Ames Research CenterGrantier, Julie, NASA/Glenn Research Center
Hack, Kurt, NASA/Glenn Research Center
Hall, Kelly, NASA/Glenn Research Center
Hamaker, Franci, NASA/Kennedy Space Center
Hange, Craig, NASA/Ames Research Center
Henry, Thad, NASA/Marshall Space Flight Center
Hill, Nancy, NASA/Marshall Space Flight Center
Hirshorn, Steven, NASA/Headquarters
Holladay, Jon, NASA/NASA Engineering and Safety Center
Hyatt, Mark, NASA/Glenn Research Center
Killebrew, Jana, NASA/Ames Research Center
Jannette, Tony, NASA/Glenn Research Center
Jenks, Kenneth, NASA/Johnson Space Center
Jones, Melissa, NASA/Jet Propulsion Laboratory
Jones, Ross, NASA/Jet Propulsion Laboratory
Leitner, Jesse, NASA/Goddard Space Flight Center
Lin, Chi, NASA/Jet Propulsion Laboratory
Mascia, Anne Marie, Graphic Artist
McKay, Terri, NASA/Marshall Space Flight Center
McNelis, Nancy, NASA/Glenn Research Center
Mendoza, Donald, NASA/Ames Research Center
Miller, Scott, NASA/Ames Research Center
Montgomery, Patty, NASA/Marshall Space Flight Center
Mosier, Gary, NASA/Goddard Space Flight Center
Noble, Lee, NASA/Langley Research Center
Oleson, Steven, NASA/Glenn Research Center
Parrott, Edith, NASA/Glenn Research Center
Powell, Christine, NASA/Stennis Space Center
Powell, Joseph, NASA/Glenn Research Center
Price, James, NASA/Langley Research Center
Rawlin, Adam, NASA/Johnson Space Center
Rochlis-Zumbado, Jennifer, NASA/Johnson Space Center
Rohn, Dennis, NASA/Glenn Research Center
Rosenbaum, Nancy, NASA/Goddard Space Flight Centerx
Ryan, Victoria, NASA/Jet Propulsion Laboratory
Sadler, Gerald, NASA/Glenn Research Center
Salazar, George, NASA/Johnson Space Center
Sanchez, Hugo, NASA/Ames Research Center
Schuyler, Joseph, NASA/Stennis Space Center
Sheehe, Charles, NASA/Glenn Research Center
Shepherd, Christena, NASA/Marshall Space Flight Center
Shull, Thomas, NASA/Langley Research Center
Singer, Bart, NASA/Langley Research Center
Slywczak, Richard, NASA/Glenn Research Center
Smith, Scott, NASA/Goddard Space Flight Center
Smith, Joseph, NASA/Headquarters
Sprague, George, NASA/Jet Propulsion LaboratoryTrase, Kathryn, NASA/Glenn Research Center
Trenkle, Timothy, NASA/Goddard Space Flight Center
Vipavetz, Kevin, NASA/Langley Research Center
Voss, Linda, Dell Services
Walters, James Britton, NASA/Johnson Space Center
Watson, Michael, NASA/Marshall Space Flight Center
Weiland, Karen, NASA/Glenn Research Center
Wiedeman, Grace, Dell Services
Wiedenmannott, Ulrich, NASA/Glenn Research Center
Witt, Elton, NASA/Johnson Space Center
Woytach, Jeffrey, NASA/Glenn Research Center
Wright, Michael, NASA/Marshall Space Flight Center
Yu, Henry, NASA/Kennedy Space Center1
NASA SYSTEMS ENGINEERING HANDBOOK1.0Introduction
1.1 Purpose
This handbook is intended to provide general 
guidance and information on systems engineer -
ing that will be useful to the NASA community. It 
provides a generic description of Systems Engineering 
(SE) as it should be applied throughout NASA. A goal of the handbook is to increase awareness and consis -
tency across the Agency and advance the practice of SE. This handbook provides perspectives relevant to NASA and data particular to NASA.
This handbook should be used as a companion for 
implementing NPR 7123.1, Systems Engineering Processes and Requirements, as well as the Center-specific handbooks and directives developed for

implementing NPR 7123.1, Systems Engineering Processes and Requirements, as well as the Center-specific handbooks and directives developed for 
implementing systems engineering at NASA. It pro -
vides a companion reference book for the various 
systems engineering-related training being offered under NASA’s auspices.
1.2 Scope and Depth
This handbook describes systems engineering best practices that should be incorporated in the develop -
ment and implementation of large and small NASA 
programs and projects. The engineering of NASA systems requires a systematic and disciplined set of 
processes that are applied recursively and iteratively for the design, development, operation, maintenance, 
and closeout of systems throughout the life cycle of 
the programs and projects. The scope of this hand -
book includes systems engineering functions regard -
less of whether they are performed by a manager or an engineer, in-house or by a contractor.
There are many Center-specific handbooks and direc-
tives as well as textbooks that can be consulted for in-depth tutorials. For guidance on systems engi -
neering for information technology projects, refer to Office of Chief Information Officer Information 
Technology Systems Engineering Handbook Version 2.0 . 
For guidance on entrance and exit criteria for mile -
stone reviews of software projects, refer to NASA-
HDBK-2203, NASA Software Engineering Handbook . 
A NASA systems engineer can also participate in the NASA Engineering Network (NEN) Systems 
Engineering Community of Practice, located at 
https://nen.nasa.gov/web/se . This Web site includes 
many resources useful to systems engineers, includ -
ing document templates for many of the work prod -
ucts and milestone review presentations required by 
the NASA SE process.21.0 Introduction
NASA SYSTEMS ENGINEERING HANDBOOK
This handbook is applicable to NASA space flight 
projects of all sizes and to research and development 
programs and projects. While all 17 processes are 
applicable to all projects, the amount of formality, 
depth of documentation, and timescales are varied as 
appropriate for the type, size, and complexity of the 
project. References to “documents” are intended to 
include not only paper or digital files but also models, graphics, drawings, or other appropriate forms that 
capture the intended information.
For a more in-depth discussion of the principles pro -
vided in this handbook, refer to the NASA Expanded 
Guidance for SE document which can be found at 
https://nen.nasa.gov/web/se/doc-repository . This hand -
book is an abridged version of that reference.3
NASA SYSTEMS ENGINEERING HANDBOOK2.0Fundamentals of  
Systems Engineering
At NASA, “systems engineering” is defined as a 
methodical, multi-disciplinary approach for the 
design, realization, technical management, opera -
tions, and retirement of a system. A “system” is the combination of elements that function together to produce the capability required to meet a need. The elements include all hardware, software, equip -
ment, facilities, personnel, processes, and procedures needed for this purpose; that is, all things required to produce system-level results. The results include sys-tem-level qualities, properties, characteristics, func -
tions, behavior, and performance. The value added by the system as a whole, beyond that contributed inde -
pendently by the parts, is primarily created by the relationship among the parts; that is, how they are interconnected.
1 It is a way of looking at the “big pic -
ture” when making technical decisions. It is a way of achieving stakeholder functional, physical, and oper -
ational performance requirements in the intended use environment over the planned life of the system within cost, schedule, and other constraints. It is a methodology that supports the containment of the life cycle cost of a system. In other words, systems engineering is a logical way of thinking.
1 Eberhardt Rechtin, Systems Architecting of Organizations: 
Why Eagles Can’t Swim .Systems engineering is the art and science of devel -
oping an operable system capable of meeting require -
ments within often opposed constraints. Systems engineering is a holistic, integrative discipline, wherein the contributions of structural engineers, electrical engineers, mechanism designers, power engineers, human factors engineers, and many more disciplines are evaluated and balanced, one against another, to produce a coherent whole that is not dom -
inated by the perspective of a single discipline.
2
Systems engineering seeks a safe and balanced design in the face of opposing interests and multiple, some -
times conflicting constraints. The systems engineer should develop the skill for identifying and focusing efforts on assessments to optimize the overall design and not favor one system/subsystem at the expense of another while constantly validating that the goals of the operational system will be met. The art is in knowing when and where to probe. Personnel with these skills are usually tagged as “systems engineers.” They may have other titles—lead systems engineer, 
2 Comments on systems engineering throughout Chapter 2  .0 
are extracted from the speech “System Engineering and the 
Two Cultures of Engineering” by Michael D  . G riffin, NASA 
Administrator  .42.0 Fundamentals of Systems Engineering
technical manager, chief engineer—but for this doc -
ument, the term “systems engineer” is used.
The exact role and responsibility of the systems engi -
neer may change from project to project depending on 
the size and complexity of the project and from phase 
to phase of the life cycle. For large projects, there may 
be one or more systems engineers. For small projects, 
the project manager may sometimes perform these 
practices. But whoever assumes those responsibil -
ities, the systems engineering functions should be 
performed. The actual assignment of the roles and 
responsibilities of the named systems engineer may 
also therefore vary. The lead systems engineer ensures 
that the system technically fulfills the defined needs 
and requirements and that a proper systems engineer -
ing approach is being followed. The systems engineer 
oversees the project’s systems engineering activities as 
performed by the technical team and directs, com -
municates, monitors, and coordinates tasks. The 
systems engineer reviews and evaluates the technical 
aspects of the project to ensure that the systems/sub -
systems engineering processes are functioning prop -
erly and evolves the system from concept to product. 
The entire technical team is involved in the systems 
engineering process.
The systems engineer usually plays the key role in 
leading the development of the concept of opera -
tions (ConOps) and resulting system architec -
ture, defining boundaries, defining and allocating 
requirements, evaluating design tradeoffs, balanc -
ing technical risk between systems, defining and 
assessing interfaces, and providing oversight of ver -
ification and validation activities, as well as many 
other tasks. The systems engineer typically leads the 
technical planning effort and has the prime respon -
sibility in documenting many of the technical plans, 
requirements and specification documents, verifica -
tion and validation documents, certification pack -
ages, and other technical documentation.In summary, the systems engineer is skilled in the 
art and science of balancing organizational, cost, 
and technical interactions in complex systems. The 
systems engineer and supporting organization are 
vital to supporting program and Project Planning 
and Control (PP&C) with accurate and timely cost 
and schedule information for the technical activities. 
Systems engineering is about tradeoffs and compro -
mises; it uses a broad crosscutting view of the system 
rather than a single discipline view. Systems engineer -
ing is about looking at the “big picture” and not only 
ensuring that they get the design right (meet require -
ments) but that they also get the right design (enable 
operational goals and meet stakeholder expectations).
Systems engineering plays a key role in the project 
organization. Managing a project consists of three 
main objectives: managing the technical aspects of 
the project, managing the project team, and manag -
ing the cost and schedule. As shown in FIGURE 2.0-1 , 
these three functions are interrelated. Systems engi -
neering is focused on the technical characteristics 
of decisions including technical, cost, and schedule 
and on providing these to the project manager. The 
Project Planning and Control (PP&C) function is 
responsible for identifying and controlling the cost 
and schedules of the project. The project manager has 
overall responsibility for managing the project team 
and ensuring that the project delivers a technically 
correct system within cost and schedule. Note that 
there are areas where the two cornerstones of project 
management, SE and PP&C, overlap. In these areas, 
SE provides the technical aspects or inputs whereas

SE provides the technical aspects or inputs whereas 
PP&C provides the programmatic, cost, and sched -
ule inputs.
This document focuses on the SE side of the dia -
gram. The practices/processes are taken from NPR 
7123.1, NASA Systems Engineering Processes 
and Requirements. Each process is described in 
much greater detail in subsequent chapters of this 52.0 Fundamentals of Systems Engineering
document, but an overview is given in the following 
subsections of this chapter.
2.1 The Common Technical 
Processes and the SE Engine
There are three sets of common technical processes in 
NPR 7123.1, NASA Systems Engineering Processes and Requirements: system design, product realiza -
tion, and technical management. The processes in each set and their interactions and flows are illustrated by the NPR systems engineering “engine” shown in 
FIGURE 2.1-1 . The processes of the SE engine are used 
to develop and realize the end products. This chap -
ter provides the application context of the 17 com -
mon technical processes required in NPR7123.1. The system design processes, the product realization processes, and the technical management processes are discussed in more detail in 
Chapters 4.0 , 5.0, and 
6.0, respectively. Processes 1 through 9 indicated in 
FIGURE 2.1-1  represent the tasks in the execution of a 
project. Processes 10 through17 are crosscutting tools for carrying out the processes.PROJECT MANAGEMENT
PROJECT MANAGEMENT ACTIVITIES
• Setting up Project Team
•P
rogrammatic Stakeholders (non-technical, non-business)
•Programmatic Planning (non-technical, non-business)
•Identifying Programmatic (non-technical) requirements•Identifying Programmatic Risks
•Technology Transfer and Commercialization
•Integration of technical and non-technical activities
•Overall Approver/Decider
System Design Processes
• Stakeholder Expectations Definition
• Technical Requirement’s Definition
• Logical Decomposition
• Design Solution Definition
Product Realization Processes
• Product Implementation
• Product Integration
• Product Verification
• Product Validation
• Product Transition
Technical Management Processes
• Technical Planning
• Requirements Management
• Interface Management
• Technical Risk Management
• Configuration Management
• Technical Data Management
• Technical Assessment
• Decision AnalysesPP&C
•PP &C Integration
•Resource Management
•Scheduling
•Cost Estimation & Assessment
•Acquisition & Contract
Management
•Risk Management
•CM/DMCommon  
Areas
•S takeholders
•Risks
•Configuration
•DataManagement
•Reviews
•Schedule
FIGURE 2.0-1  SE in C ontext of Overall Project Management62.0 Fundamentals of Systems Engineering
Requirements Definition
Processes 
1.  Stakeholders Expectations 
Definition
2.  Technical Requirements  
3.  Logical Decomposition
4.  Design Solution DefinitionSystem Design 
ProcessesRequirements Flow Down 
from Level above
Technical Management 
Processes
10.  Technical Planning
11.  Requirement Management 
12.  Interface Management 13.  Technical Risk Management 
14.  Configuration Management 
15.  Technical Data Management 
16.  Technical Assessment 
Technical Decision  
Analysis Process 
17.  Decision Analysis 9.  Product Transition
8.  Product Validation
7.  Product Verification
6.  Product Integration
5.  Product ImplementationProduct Realization 
Processes
System Design Processes 
applied to each product 
layer down through system 
structureProduct Realization 
Processes applied to each 
product layer up through 
system structureRequirements Flow Down 
To Level belowRealized Products 
to Level above
Realized Products
From Level belowCross -
cuttingCross-cutting
Technical Solution 
Definition Processes Technical Planning
Processes 
Technical Control
Processes Product Transition
Processes 
Evaluation Processes 
Design Realization
Processes Technical Assessment
Processes 
FIGURE 2.1-1  The S ystems Engineering Engine (NPR 7123  .1)
• System Design Processes:  The four system 
design processes shown in FIGURE 2.1-1  are used to 
define and baseline stakeholder expectations, gen -
erate and baseline technical requirements, decom -
pose the requirements into logical and behavioral 
models, and convert the technical requirements into a design solution that will satisfy the base -
lined stakeholder expectations. These processes are applied to each product of the system struc -
ture from the top of the structure to the bottom until the lowest products in any system structure branch are defined to the point where they can be built, bought, or reused. All other products in the system structure are realized by implementation or integration.
• Product Realization Processes:  The product real -
ization processes are applied to each operational/mission product in the system structure starting from the lowest level product and working up to higher level integrated products. These processes are used to create the design solution for each product (through buying, coding, building, or reusing) and to verify, validate, and transition up to the next hierarchical level those products that satisfy their design solutions and meet stakeholder 72.0 Fundamentals of Systems Engineering
expectations as a function of the applicable life 
cycle phase.
• Technical Management Processes:  The techni -
cal management processes are used to establish and evolve technical plans for the project, to man -
age communication across interfaces, to assess progress against the plans and requirements for the system products or services, to control tech -
nical execution of the project through to comple -
tion, and to aid in the decision-making process.
TABLE 2.1-1 Alignment of the 17 SE Processes to AS9100
SE Process AS9100 Requirement
Stakeholder Expectations Customer Requirements
Technical Requirements 
DefinitionPlanning of Product Realization
Logical Decomposition Design and Development Input
Design Solution Definition Design and Development Output
Product Implementation Control of Production
Product Integration Control of Production
Product Verification Verification
Product Validation Validation
Product Transition Control of Work Transfers; Post Delivery Support, Preservation of Product
Technical Planning Planning of Product Realization; Review of Requirements; Measurement, Analysis and Improvement
Requirements Management Design and Development Planning; Purchasing
Interface Management Configuration Management
Technical Risk Management Risk Management
Configuration Management Configuration Management; Identification and Traceability; Control of Nonconforming Product
Technical Data Management Control of Documents; Control of Records; Control of Design and Development Changes
Technical Assessment Design and Development Review
Decision Analysis Measurement, Analysis and Improvement; Analysis of DataThe pro
cesses within the SE engine are used both 
iteratively and recursively. As defined in NPR 7123.1, 
“iterative” is the “application of a process to the same product or set of products to correct a discovered disc
repancy or other variation from requirements,” 
whereas “recursive” is defined as adding value to the system “by the repeated application of processes to design next lower layer system products or to real -
ize next upper layer end products within the system structure. This also applies to repeating application of the same processes to the system structure in the next life cycle phase to mature the system definition and satisfy phase success criteria.” The technical processes are applied recursively and iteratively to break down the initializing concepts of the system to a level of detail concrete enough that the technical team can implement a product from the information. Then the processes are applied recursively and iteratively to 82.0 Fundamentals of Systems Engineering
integrate the smallest product into greater and larger 
systems until the whole of the system or product has been assembled, verified, validated, and transitioned.
For a detailed example of how the SE Engine could 
be used, refer to the NASA Expanded Guidance for SE document at
 https://nen.nasa.gov/web/se/
doc-repository .
AS9100 is a widely adopted and standardized qual -
ity management system developed for the commer -
cial aerospace industry. Some NASA Centers have chosen to certify to the AS9100 quality system and may require their contractors to follow NPR 7123.1. 
TABLE 2.1-1  shows how the 17 NASA SE processes 
align with AS9100.2.2 An Overview of the SE 
Engine by Project Phase
FIGURE 2.2-1  conceptually illustrates how the SE 
engine is used during each phase of a project (Pre-
Phase A through Phase F). The life cycle phases are described in 
TABLE 2.2-1 . FIGURE 2.2-1  is a conceptual 
diagram. For full details, refer to the poster version of this figure, which is located at 
https://nen.nasa.gov/
web/se/doc-repository .
Pre-Phase A:

Concept Studies Implementa tion ApprovalTechnical Development Technic al Management5.2Key De cision Points:
Major Reviews:Feasible Concept Top-Level Architecture Functional BaselineAllocated
BaselineAs-Deployed  Baseline
6.1
6.86.1 
6.8 6.1 
6.8 6.1 
6.8 6.1 
6.8 6.1 
6.8 6.1 
6.8 ?
??
5.35.45.5
5.14.24.1
4.3
4.4
??
??
??
?4.24.1
4.3
4.4
5.15.35.45.5
5.2Product
BaselinePhase F:
Closeout Phase E:
Operations &
Sustainment Phase D:
System Assembly, 
Integration & Test, LaunchPhase B:
Preliminary Design &
Technology CompletionPhase A:
Concept & Technology
Development Phase C:
Final Design &
Fabrication
6.2
6.76.66.56.46.3Formulation
FIGURE 2.2-1  Minia ture Version of the Poster-Size NASA Project Life Cycle  
Process Flow for Flight and Ground Systems Accompanying this HandbookTh
e uppermost horizontal portion of this chart is 
used as a reference to project system maturity, as the 
project progresses from a feasible concept to an as-de -
ployed system; phase activities; Key Decision Points (KDPs); and major project reviews. The next major horizontal band shows the technical development 92.0 Fundamentals of Systems Engineering
processes (steps 1 through 9) in each project phase. 
The SE engine cycles five times from Pre-Phase A through Phase D. Note that NASA’s management has structured Phases C and D to “split” the tech -
nical development processes in half in Phases C and D to ensure closer management control. The engine is bound by a dashed line in Phases C and D. Once a project enters into its operational state (Phase E) and closes out (Phase F), the technical work shifts to activities commensurate with these last two proj -
ect phases. The next major horizontal band shows the eight technical management processes (steps 10 through 17) in each project phase. The SE engine cycles the technical management processes seven times from Pre-Phase A through Phase F.TABLE 2.2-1  Pr oject Life Cycle Phases
Phase Purpose Typical OutcomesPre-FormulationPre-Phase A  
Concept 
StudiesTo produce a broad spectrum of ideas and alternatives for missions from which new programs/projects can be selected. Determine feasibility of desired system, develop mission concepts, draft system-level requirements, assess performance, cost, and schedule feasibility; identify potential technology needs, and scope.Feasible system concepts in the form of simulations, analysis, study reports, models, and mock-upsFormulationPhase A 
Concept and Technology DevelopmentTo determine the feasibility and desirability of a suggested new system and establish an initial baseline compatibility with NASA’s strategic plans. Develop final mission concept, system-level requirements, needed system technology developments, and program/project technical management plans.System concept definition in the form of simulations, analysis, engineering models and mock-ups, and trade study definition
Phase B 
Preliminary Design and Technology CompletionTo define the project in enough detail to establish an initial baseline capable of meeting mission needs. Develop system structure end product (and enabling product) requirements and generate a preliminary design for each system structure end product.End products in the form of mock-ups, trade study results, specification and interface documents, and prototypesImplementationPhase C  
Final Design and FabricationTo complete the detailed design of the system (and its associated subsystems, including its operations systems), fabricate hardware, and code software. Generate final designs for each system structure end product.End product detailed designs, end product component fabrication, and software development
Phase D  
System Assembly, Integration and Test, LaunchTo assemble and integrate the system (hardware, software, and humans), meanwhile developing confidence that it is able to meet the system requirements. Launch and prepare for operations. Perform system end product implementation, assembly, integration and test, and transition to use.Operations-ready system end product with supporting related enabling products
Phase E 
Operations and SustainmentTo conduct the mission and meet the initially identified need and maintain support for that need. Implement the mission operations plan.Desired system
Phase F 
CloseoutTo implement the systems decommissioning/disposal plan developed in Phase E and perform analyses of the returned data and any returned samples.Product closeout102.0 Fundamentals of Systems Engineering
2.3 Example of Using the SE Engine
In Pre-Phase A, the SE engine is used to develop the 
initial concepts; clearly define the unique roles of humans, hardware, and software in performing the 
missions objectives; establish the system functional 
and performance boundaries; develop/identify a pre -
liminary/draft set of key high-level requirements, define one or more initial Concept of Operations (ConOps) scenarios; realize these concepts through iterative modeling, mock-ups, simulation, or other 
means; and verify and validate that these concepts 
and products would be able to meet the key high-level requirements and ConOps. The operational concept must include scenarios for all significant operational situations, including known off-nominal situations. 
To develop a useful and complete set of scenarios, 
important malfunctions and degraded-mode opera -
tional situations must be considered. The importance of early ConOps development cannot be underesti -
mated. As system requirements become more detailed and contain more complex technical information, 
it becomes harder for the stakeholders and users to 
understand what the requirements are conveying; i.e., it may become more difficult to visualize the end product. The ConOps can serve as a check in identi -
fying missing or conflicting requirements.
Note that this Pre-Phase A initial concepts develop -
ment work is not the formal verification and valida -
tion program that is performed on the final product, 
but rather it is a methodical run through ensuring that the concepts that are being developed in this 
Pre-Phase A are able to meet the likely requirements 
and expectations of the stakeholders. Concepts are developed to the lowest level necessary to ensure that they are feasible and to a level that reduces the risk low enough to satisfy the project. Academically, this 
process could proceed down to the circuit board level 
for every system; however, that would involve a great deal of time and money. There may be a higher level or tier of product than circuit board level that would enable designers to accurately determine the feasibil -
ity of accomplishing the project, which is the purpose of Pre-Phase A.
During Phase A, the recursive use of the SE engine 
is continued, this time taking the concepts and draft key requirements that were developed and validated during Pre-Phase A and fleshing them out to become the set of baseline system requirements and ConOps. During this phase, key areas of high risk might be 
simulated to ensure that the concepts and require -
ments being developed are good ones and to identify 
verification and validation tools and techniques that will be needed in later phases.
During Phase B, the SE engine is applied recursively 
to further mature requirements and designs for all products in the developing product tree and perform verification and validation of concepts to ensure that the designs are able to meet their requirements. Operational designs and mission scenarios are evalu -
ated and feasibility of execution within design capa -
bilities and cost estimates are assessed.
Phase C again uses the left side of the SE engine to 
finalize all requirement updates, finalize the ConOps 
validation, develop the final designs to the lowest 
level of the product tree, and begin fabrication.
Phase D uses the right side of the SE engine to recur -
sively perform the final implementation, integration, 
verification, and validation of the end product, and at 
the final pass, transition the end product to the user.
The technical management processes of the SE engine 
are used in Phases E and F to monitor performance; control configuration; and make decisions associ -
ated with the operations, sustaining engineering, and closeout of the system. Any new capabilities or upgrades of the existing system reenter the SE engine as new developments.112.0 Fundamentals of Systems Engineering
2.4 Distinctions between 
Product Verification and Product Validation
From a process perspective, the Product Verification 
and Product Validation processes may be similar in nature, but the objectives are fundamentally different:
• Verification of a product shows proof of compli -
ance with requirements—that the product can meet each “shall” statement as proven though per -
formance of a test, analysis, inspection, or demon -
stration (or combination of these).
• Validation of a product shows that the prod -

uct accomplishes the intended purpose in the intended environment—that it meets the expec -
tations of the customer and other stakeholders as shown through performance of a test, analysis, inspection, or demonstration.
Verification testing relates back to the approved requirements set and can be performed at different 
stages in the product life cycle. The approved specifi -
cations, drawings, parts lists, and other configuration 
documentation establish the configuration baseline of that product, which may have to be modified at a later time. Without a verified baseline and appropri -
ate configuration controls, later modifications could be costly or cause major performance problems.
Validation relates back to the ConOps document. 
Validation testing is conducted under realistic con -
ditions (or simulated conditions) on end products for 
the purpose of determining the effectiveness and suit -
ability of the product for use in mission operations by 
typical users. Validation can be performed in each development phase using phase products (e.g., mod -
els) and not only at delivery using end products.It is appropriate for verification and validation meth -
ods to differ between phases as designs advance. The ultimate success of a program or project may relate to the frequency and diligence of validation efforts during the design process, especially in Pre-Phase A and Phase A during which corrections in the direc -
tion of product design might still be made cost-effec -
tively. The question should be continually asked, “Are we building the right product for our users and other stakeholders?” The selection of the verification or val -
idation method is based on engineering judgment as to which is the most effective way to reliably show the 
product’s conformance to requirements or that it will 
operate as intended and described in the ConOps.
2.5 Cost Effectiveness 
Considerations
The objective of systems engineering is to see that the 
system is designed, built, and can be operated so that it accomplishes its purpose safely in the most cost-ef -
fective way possible considering performance, cost, schedule, and risk. A cost-effective and safe system should provide a particular kind of balance between effectiveness and cost. This causality is an indefinite one because there are usually many designs that meet the cost-effective condition.
Design trade studies, an important part of the sys -
tems engineering process, often attempt to find 
designs that provide the best combination of cost and effectiveness. At times there are alternatives that 
either reduce costs without reducing effectiveness or 
increase effectiveness without increasing cost. In such “win-win” cases, the systems engineer’s decision is easy. When the alternatives in a design trade study require trading cost for effectiveness, the decisions become harder.122.0 Fundamentals of Systems Engineering
FIGURE 2.5-1  shows that the life cycle costs of a 
program or project tend to get “locked in” early in 
design and development. The cost curves clearly show that late identification of and fixes to problems cost considerably more later in the life cycle. Conversely, descopes taken later versus earlier in the project life cycle result in reduced cost savings. This figure, obtained from the Defense Acquisition University, is an example of how these costs are determined by the early concepts and designs. The numbers will vary from project to project, but the general shape of the curves and the message they send will be similar. For example, the figure shows that during design, only about 15% of the costs might be expended, but the design itself will commit about 75% of the life cycle costs. This is because the way the system is designed will determine how expensive it will be to test, man -
ufacture, integrate, operate, and sustain. If these fac-tors have not been considered during design, they pose significant cost risks later in the life cycle. Also note that the cost to change the design increases as you get later in the life cycle. If the project waits until verification to do any type of test or analysis, any problems found will have a significant cost impact to redesign and reverify.THE SYSTEMS ENGINEER’S DILEMMA
At each cost-effective solution:
• To re
duce cost at constant risk, performance must be reduced.
• To re
duce risk at constant cost, performance must be reduced.
• To re
duce cost at constant performance, higher risks must be accepted.
• To re
duce risk at constant performance, higher costs must be accepted.
In this context, time in the schedule is often a critical resource, so that schedule  behaves like a kind of cost .
The technical team may have to choose among designs 
that differ in terms of numerous attributes. A variety of methods have been developed that can be used to help uncover preferences between attributes and to quan -
tify subjective assessments of relative value. When this can be done, trades between attributes can be assessed quantitatively. Often, however, the attributes are incompatible. In the end, decisions need to be made in spite of the given variety of attributes. There are several decision analysis techniques (
Section 6.8 ) 
that can aid in complex decision analysis. The systems engineer should always keep in mind the information that needs to be available to help the decision-makers choose the most cost-effective option.
2.6 Human Systems Integration 
(HSI) in the SE Process
As noted at the beginning of NPR 7123.1, the “sys -
tems approach is applied to all elements of a system 
(i.e., hardware, software, human systems integra -
tion. In short, the systems engineering approach must equally address and integrate these three key elements: hardware, software, and human systems 132.0 Fundamentals of Systems Engineering
integration. Therefore, the human element is some -
thing that integration and systems engineering pro -
cesses must address. The definition of “system” in 
NPR 7123.1 is inclusive; i.e., a system is “the combi -
nation of elements that function together to produce the capability required to meet a need. The elements include all hardware, software, equipment, facilities, personnel, processes, and procedures needed for this purpose. For additional information and guidance on his, refer to Section 2.6 of the NASA Expanded Guidance for Systems Engineering at 
https://nen.
nasa.gov/web/se/doc-repository .0%10%20%
MCR SRR SDR PDR CDR SIR ORR DR/DRR30%40% 3–6×45%
ConceptDesign
DevelopProd/TestOperations 
through 
Disposal75%90%
100%
50%
20%
15%8%20–100×500–1000×
50%60%70%80%90%100%Cumulative Percentage Life Cycle Cost against Time
TimeCommitted Life  Cycle Costs
% Completed  
(Costs Expended)Cost to Change Design Direction
MCR Mission Concept Review CDR Critical Design Review
SRR System Requirements Review SIR System Integration Review
SDR System Definition Review ORR Operational Readiness Review
PDR Preliminary Design Review DR/DRR Decommissioning/Disposal Readiness Review
Adapted from INCOSE-TP-2003-002-04, 2015
FIGURE 2.5-1  Lif e-Cycle Cost Impacts from Early Phase Decision-Making
2.7 Competency Model for 
Systems Engineers
TABLE 2.7-1  provides a summary of the Competency 
Model for Systems Engineering. For more informa -
tion on the NASA SE Competency model refer to: 
http://appel.nasa.gov/competency-model/ .
There are four levels of proficiencies associated with 
each of these competencies:
• Team Practitioner/Technical Engineer
• Team Lead/Subsystem Lead
• Project Systems Engineer
• Chief Engineer142.0 Fundamentals of Systems Engineering
TABLE 2.7-1  NASA System Engineering Competency Model
Competency 
AreaCompetency Description
SE 1.0 
System 
DesignSE 1.1 
Stakeholder Expectation Definition & ManagementEliciting and defining use cases, scenarios, concept of operations and stakeholder expectations. This includes identifying stakeholders, establishing support strategies, establishing a set of Measures of Effectiveness (MOEs), validating stakeholder expectation statements, and obtaining commitments from the customer and other stakeholders, as well as using the baselined stakeholder expectations for product validation during product realization
SE 1.2 
Technical Requirements DefinitionTransforming the baseline stakeholder expectations into unique, quantitative, and measurable technical requirements expressed as “shall” statements that can be used for defining the design solution. This includes analyzing the scope of the technical problems to be solved, defining constraints affecting the designs, defining the performance requirements, validating the resulting technical requirement statements, defining the Measures of Performance (MOPs) for each MOE, and defining appropriate Technical Performance Measures (TPMs) by which technical progress will be assessed.
SE 1.3

SE 1.2 
SE 1.3   
Logical DecompositionTransforming the defined set of technical requirements into a set of logical decomposition models and their associated set of derived technical requirements for lower levels of the system, and for input to the design solution efforts. This includes decomposing and analyzing by function, time, behavior, data flow, object, and other models. It also includes allocating requirements to these decomposition models, resolving conflicts between derived requirements as revealed by the models, defining a system architecture for establishing the levels of allocation, and validating the derived technical requirements.
SE 1.4  
Design Solution DefinitionTranslating the decomposition models and derived requirements into one or more design solutions, and using the Decision Analysis process to analyze each alternative and for selecting a preferred alternative that will satisfy the technical requirements. A full technical data package is developed describing the selected solution. This includes generating a full design description for the selected solution; developing a set of ‘make-to,’ ‘buy-to,’ ‘reuse-to,’ specifications; and initiating the development or acquisition of system products and enabling products.
SE 2.0 
Product RealizationSE 2.1  
Product ImplementationGenerating a specific product through buying, making, or reusing so as to satisfy the design requirements. This includes preparing the implementation strategy; building or coding the produce; reviewing vendor technical information; inspecting delivered, built, or reused products; and preparing product support documentation for integration.
SE 2.2  
Product IntegrationAssembling and integrating lower-level validated end products into the desired end product of the higher-level product. This includes preparing the product integration strategy, performing detailed planning, obtaining products to integrate, confirming that the products are ready for integration, preparing the integration environment, and preparing product support documentation.
SE 2.3  
Product VerificationProving the end product conforms to its requirements. This includes preparing for the verification efforts, analyzing the outcomes of verification (including identifying anomalies and establishing recommended corrective actions), and preparing a product verification report providing the evidence of product conformance with the applicable requirements.
(continued)152.0 Fundamentals of Systems Engineering
SE 2.0 
Product 
RealizationSE 2.4  
Product ValidationConfirming that a verified end product satisfies the stakeholder expectations for its intended use when placed in its intended environment and ensuring that any anomalies discovered during validation are appropriately resolved prior to product transition. This includes preparing to conduct product validation, performing the product validation, analyzing the results of validation (including identifying anomalies and establishing recommended corrective actions), and preparing a product validation report providing the evidence of product conformance with the stakeholder expectations baseline.
SE 2.5  
Product TransitionTransitioning the verified and validated product to the customer at the next level in the system structure. This includes preparing to conduct product transition, evaluating the product and enabling product readiness for product transition, preparing the product for transition (including handling, storing, and shipping preparation), preparing sites, and generating required documentation to accompany the product
SE 3.0 
Technical ManagementSE 3.1 
Technical PlanningPlanning for the application and management of each common technical process, as well as identifying, defining, and planning the technical effort necessary to meet project objectives. This includes preparing or updating a planning strategy for each of the technical processes, and determining deliverable work products from technical efforts; identifying technical reporting requirements; identifying entry and success criteria for technical reviews; identifying product and process measures to be used; identifying critical technical events; defining cross domain interoperability and collaboration needs; defining the data management approach; identifying the technical risks to be addressed in the planning effort; identifying tools and engineering methods to be employed; and defining the approach to acquire and maintain technical expertise needed. This also includes preparing the Systems Engineering Management Plan (SEMP) and other technical plans; obtaining stakeholder commitments to the technical plans; and issuing authorized technical work directives to implement the technical work
SE 3.2 
Requirements ManagementManaging the product requirements, including providing bidirectional traceability, and managing changes to establish requirement baselines over the life cycle of the system products. This includes preparing or updating a strategy for requirements management; selecting an appropriate requirements management tool; training technical team members in established requirement management procedures; conducting expectation and requirements traceability audits; managing expectation and requirement changes; and communicating expectation and requirement change information
SE 3.3 
Interface ManagementEstablishing and using formal interface management to maintain internal and external interface definition and compliance among the end products and enabling products. This includes preparing interface management procedures, identifying interfaces, generating and maintaining interface documentation, managing changes to interfaces, disseminating interface information, and conducting interface control
SE 3.4 
Technical Risk ManagementExamining on a continual basis the risks of technical deviations from the plans, and identifying potential technical problems before they occur. Planning, invoking, and performing risk-handling activities as needed across the life of the product or project to mitigate impacts on meeting technical objectives. This includes developing the strategy for technical risk management, identifying technical risks, and conducting technical risk assessment; preparing for technical risk mitigation, monitoring the status of each technical risk, and implementing technical risk mitigation and contingency action plans when applicable thresholds have been triggered.
(continued)162.0 Fundamentals of Systems Engineering
SE 3.0 
Technical 
ManagementSE 3.5 
Configuration ManagementIdentifying the configuration of the product at various points in time, systematically controlling changes to the configuration of the product, maintaining the integrity and traceability of product configuration, and preserving the records of the product configuration throughout its life cycle. This includes establishing configuration management strategies and policies, identifying baselines to be under configuration control, maintaining the status of configuration documentation, and conducting configuration audits
SE 3.6 
Technical Data ManagementIdentifying and controlling product-related data throughout its life cycle; acquiring, accessing, and distributing data needed to develop, manage, operate, support, and retire system products; managing and disposing data as records; analyzing data use; obtaining technical data feedback for managing the contracted technical efforts; assessing the collection of appropriate technical data and information; maintaining the integrity and security of the technical data, effectively managing authoritative data that defines, describes, analyzes, and characterizes a product life cycle; and ensuring consistent, repeatable use of effective Product Data and Life-cycle Management processes, best practices, interoperability approaches, methodologies, and traceability. This includes establishing technical data management strategies 
and policies; maintaining revision, status, and history of stored technical data and 
associated metadata; providing approved, published technical data; providing technical data to authorized parties; and collecting and storing required technical data.
SE 3.7 
Technical AssessmentMonitoring progress of the technical effort and providing status information for support of the system design, product realization, and technical management efforts. This includes developing technical assessment strategies and policies, assessing technical work productivity, assessing product quality, tracking and trending technical metrics, and conducting technical, peer, and life cycle reviews.
SE 3.8

SE 3.7 
SE 3.8 
Technical Decision AnalysisEvaluating technical decision issues, identifying decision criteria, identifying alternatives, analyzing alternatives, and selecting alternatives. Performed throughout the system life cycle to formulate candidate decision alternatives, and evaluate their impacts on health and safety, technical, cost, and schedule performance. This includes establishing guidelines for determining which technical issues are subject to formal analysis processes; defining the criteria for evaluating alternative solutions; identifying alternative solutions to address decision issues; selecting evaluation methods; selecting recommended solutions; and reporting the results and findings with recommendations, impacts, and corrective actions.17
NASA SYSTEMS ENGINEERING HANDBOOK3.0NASA Program/Project Life Cycle
One of the fundamental concepts used within 
NASA for the management of major systems 
is the program/project life cycle, which categorizes everything that should be done to accomplish a pro -
gram or project into distinct phases that are separated by Key Decision Points (KDPs). KDPs are the events at which the decision authority determines the readi -
ness of a program/project to progress to the next phase of the life cycle (or to the next KDP).  Phase boundaries 
are defined so that they provide natural points for “go” or “no-go” decisions. Decisions to proceed may be qualified by liens that should be removed within an agreed-to time period. A program or project that fails to pass a KDP may be allowed to try again later after addressing deficiencies that precluded passing the KDP, or it may be terminated.
All systems start with the recognition of a need or the 
discovery of an opportunity and proceed through var -
ious stages of development to the end of the project. While the most dramatic impacts of the analysis and optimization activities associated with systems engineer -
ing are obtained in the early stages, decisions that affect cost continue to be amenable to the systems approach even as the end of the system lifetime approaches.Decomposing the program/project life cycle into phases organizes the entire process into more man -
ageable pieces. The program/project life cycle should provide managers with incremental visibility into the progress being made at points in time that fit with the management and budgetary environments.
For NASA projects, the life cycle is defined in the 
applicable governing document:
• For space flight projects:  NPR 7120.5, NASA 
Space Flight Program and Project Management Requirements
• For information technology:  NPR 7120.7, 
NASA Information Technology and Institutional Infrastructure Program and Project Management Requirements
• For NASA research and technology : NPR 7120.8, 
NASA Research and Technology Program and Project Management Requirements
• For software:  NPR 7150.2 NASA Software 
Engineering Requirements183.0 NASA Program/Project Life Cycle
For example, NPR 7120.5 defines the major NASA 
life cycle phases as Formulation and Implementation. For space flight systems projects, the NASA life cycle phases of Formulation and Implementation divide into the following seven incremental pieces. The phases of the project life cycle are:
Program Pre-Formulation:
• Pre-Phase A:  Concept Studies
Program Formulation
• Phase A:  Concept and Technology Development
• Phase B: Preliminary Design and Technology 
Completion
Program Implementation:
• Phase C:  Final Design and Fabrication• Phase D: System Assembly, Integration and Test, 
Launch
• Phase E:  Operations and Sustainment
• Phase F:  Closeout
FIGURE 3.0-1  is taken from NPR 7120.5 and provides 
the life cycle for NASA space flight projects and identi -
fies the KDPs and reviews that characterize the phases. More information concerning life cycles can be found in the NASA Expanded Guidance for SE document at 
https://nen.nasa.gov/web/se/doc-repository  and in the 
SP-2014-3705, NASA Space Flight Program and Project Management Handbook .
TABLE 3.0-1  is taken from NPR 7123.1 and represents 
the product maturity for the major SE products developed and matured during the product life cycle.
NASA Life-Cycle 
PhasesFORMULATION IMPLEMENTATION
Project Life-Cycle 
PhasesPre-Phase A:
Concept StudiesPhase A:
Concept and 
Technology 
DevelopmentPhase B:
Preliminary Design 
and Technology 
CompletionPhase C:
Final Design and 
FabricationPhase D:
Integration & Test, 
Launch & CheckoutPhase E:
Operations and 
SustainmentPhase F:
Closeout
Project Life-Cycle Gates, Documents, and Major Events
Agency Reviews
Human Space 
Flight Project Life-Cycle Reviews
1,2
 Re-flights
Rob
otic Mission 
Project Life Cycle Reviews
1,2
Other Reviews
Supporting 
Reviews
FOOTNOTES
1. Fl
exibility is allowed as to the timing, number, and content of reviews as long as the equivalent 
information is provided at each KDP and the approach is fully documented in the Project Plan.
2. Li
fe-cycle review objectives and expected maturity states for these reviews and the attendant 
KDPs are contained in Table 2-5 and Appendix D Table D-3 of this handbook
3. PR
R is needed only when there are multiple copies of systems. It does not require an SRB. Timing 
is notional.
4. CE
RRs are established at the discretion of program .
5. Fo
r robotic missions, the SRR and the MDR may be combined.
6. SA
R generally applies to human space flight.
7. Ti
ming of the ASM is determined by the MDAA. It may take place at any time during Phase A.
  Red triangles represent life-cycle reviews that require SRBs. The Decision Authority, A
dministrator, MDAA, or Center Director may request the SRB to conduct other reviews.ACRONYMSASM – Acquisition Strategy MeetingCDR – Critical Design ReviewCERR – Critical Events Readiness ReviewDR – Decommissioning ReviewDRR – Disposal Readiness ReviewFA – Formulation AgreementFAD – Formulation Authorization DocumentFRR – Flight Readiness ReviewKDP – Key Decision PointLRR – Launch Readiness ReviewLV – Launch VehicleMCR – Mission Concept ReviewMDR – Mission Definition ReviewMRR – Mission Readiness ReviewORR – Operational Readiness ReviewPDR – Preliminary Design ReviewPFAR – Post-Flight Assessment ReviewPLAR – Post-Launch Assessment ReviewPRR – Production Readiness ReviewSAR – System Acceptance ReviewSDR – System Definition ReviewSIR – System Integration ReviewSMSR – Safety and Mission Success ReviewSRB – Standing Review BoardSRR – System Requirements Review
FIGURE 3.0-1 NASA Space Flight Project Life Cycle from NPR 7120 .5EApproval for  
FormulationApproval for  
Implementation
KDP A
Preliminary Project 
RequirementsPreliminary  
Project PlanBaseline  
Project PlanLaunch End of Mission Final Archival 
of Data
Inspections and 
Refurbishment
 Re-enters appropriate life-cycle 
phase if modifications are 
needed between flightsEnd of FlightFAD
MCR
MCRASM7
SRR
SRRSDR
MDR
5PDR
PDRSIR
SIRORR
ORRFRR
MRRPLAR
PLAR
SMSR,LRR (LV), FRR (LV) SAR
6CERR4
CERR4PFARDR
DRDRR
DRRCDR/  
PRR
3
CDR/  
PRR3FAKDP B KDP C KDP D KDP F KDP E
Peer Reviews, Subsystem PDFs, Subsystem CDRs, and System Reviews193.0 NASA Program/Project Life Cycle
TABLE 3.0-1  SE Product Maturity from NPR 7123  .1
Formulation ImplementationProductsUncoupled/  
Loosely CoupledKDP 0 KDP I Periodic KDPs
Tightly Coupled 
ProgramsKDP 0 KDP I KDP II KDP III Periodic KDPs
Projects and Single Project ProgramsPre-
Phase APhase A Phase B Phase C Phase D Phase E Phase F
KDP A KDP B KDP C KDP D KDP E KDP F
MCR SRR MDR/SDR PDR CDR SIR ORR FRR DR DRR
Stakeholder identification and **Baseline Update Update Update
Concept definition **Baseline Update Update Update Update
Measure of effectiveness 
definition**Approve
Cost and schedule for technical Initial Update Update Update Update Update Update Update Update
SEMP1Preliminary **Baseline **Baseline Update Update Update
Requirements Preliminary **Baseline Update Update Update
Technical Performance Measures definition**Approve
Architecture definition **Baseline
Allocation of requirements to 
next lower level**Baseline
Required leading indicator trends**Initial Update Update Update
Design solution definition Preliminary **Preliminary **Baseline Update Update
Interface definition(s) Preliminary Baseline Update Update
Implementation plans (Make/code, buy, reuse)Preliminary Baseline Update
Integration plans Preliminary Baseline Update **Update
Verification and validation 
plansApproach Preliminary Baseline Update Update
Verification and validation results**Initial **Preliminary **Baseline
Transportation criteria and instructionsInitial Final Update
Operations plans
Baseline Update Update **Update
Operational procedures Preliminary Baseline **Update Update
Certification (flight/use) Preliminary **Final
Decommissioning plans Preliminary Preliminary Preliminary **Baseline Update **Update
Disposal plans Preliminary Preliminary Preliminary **Baseline Update Update **Update
** Item is a required product for that review
1  S EMP is baselined at SRR for projects, tightly coupled programs and single-project programs, and at MDR/SDR for uncoupled, 
and loosely coupled programs  .203.0 NASA Program/Project Life Cycle
3.1 Program Formulation

The program Formulation Phase establishes a cost-ef -
fective program that is demonstrably capable of 
meeting Agency and mission directorate goals and objectives. The program Formulation Authorization Document (FAD) authorizes a Program Manager (PM) to initiate the planning of a new program and to perform the analyses required to formulate a sound program plan. The lead systems engineer provides the technical planning and concept development or this phase of the program life cycle. Planning includes identifying the major technical reviews that are needed and associated entrance and exit criteria. Major reviews leading to approval at KDP I are the SRR, SDR, PDR, and governing Program Management Council (PMC) review. A summary of the required gate products for the program Formulation Phase can be found in the governing NASA directive (e.g., NPR 7120.5 for space flight programs, NPR 7120.7 for IT projects, NPR 7120.8 for research and tech -
nology projects). Formulation for all program types is the same, involving one or more program reviews followed by KDP I where a decision is made approv -
ing a program to begin implementation.
3.2 Program Implementation
During the program Implementation phase, the PM works with the Mission Directorate Associate Administrator (MDAA) and the constituent project 
SPACE FLIGHT PROGRAM FORMULATION
Purpose
To establish a cost-effective program that is demonstrably capable of meeting Agency and mission directorate goals and objectives
Typical Activities and Their Products for Space Flight Programs
• Identify program stakeholders and users
• Develop program requirements based on user expectations and allocate them to initial projects• Identify NASA risk classification
• Define and approve program acquisition strategies• Develop interfaces to other programs• Start developing technologies that cut across multiple projects within the program
• Derive initial cost estimates and approve a program budget based on the project’s life cycle costs• Perform required program Formulation technical activities defined in NPR 7120.5• Satisfy program Formulation reviews’ entrance/success criteria detailed in NPR 7123.1• Develop a clear vision of the program’s benefits and usage in the operational era and document it in a ConOps
Rev
iews
• MCR
 (pre-Formulation)
• SRR
• SDR213.0 NASA Program/Project Life Cycle
managers to execute the program plan cost-effec-
tively. Program reviews ensure that the program continues to contribute to Agency and mission directorate goals and objectives within funding con -
straints. A summary of the required gate products for the program Implementation Phase can be found in the governing NASA directive; e.g., NPR 7120.5 for space flight programs. The program life cycle has two different implementation paths, depending on pro -
gram type. Each implementation path has different types of major reviews. It is important for the sys -
tems engineer to know what type of program a proj -
ect falls under so that the appropriate scope of the technical work, documentation requirements, and set of reviews can be determined.SPACE FLIGHT PROGRAM IMPLEMENTATION
Purpose
To execute the program and constituent projects and ensure that the program continues to contribute to Agency goals and objectives within funding constraints
Typical Activities and Their Products
• Initiate projects through direct assignment or competitive process (e.g., Request for Proposal (RFP), 
Announcement of Opportunity (AO)
• Monitor project’s formulation, approval, implementation, integration, operation, and ultimate 
decommissioning
• Adjust program as resources and requirements change• Perform required program Implementation technical activities from NPR 7120.5• Satisfy program Implementation reviews’ entrance/success criteria from NPR 7123.1
Rev
iews
• PS
R/PIR (uncoupled and loosely coupled programs only)
• Re
views synonymous (not duplicative) with the project reviews in the project life cycle (see FIGURE 3.0-4 ) 
through Phase D (single-project and tightly coupled programs only)
3.3 Project Pre-Phase A: 
Concept Studies
The purpose of Pre-Phase A is to produce a broad 
spectrum of ideas and alternatives for missions from which new programs/projects can be selected. During Pre-Phase A, a study or proposal team anal -
yses a broad range of mission concepts that can fall within technical, cost, and schedule constraints and that contribute to program and Mission Directorate goals and objectives. Pre-Phase A effort could include focused examinations on high-risk or high tech -
nology development areas. These advanced studies, along with interactions with customers and other potential stakeholders, help the team to identify promising mission concept(s). The key stakehold -
ers (including the customer) are determined and 223.0 NASA Program/Project Life Cycle
SPACE FLIGHT PRE‑PHASE A: CONCEPT STUDIES
Purpose
To produce a broad spectrum of ideas and alternatives for missions from which new programs and projects can be selected. Determine feasibility of desired system; develop mission concepts; draft system-level requirements; assess performance, cost, and schedule feasibility; identify potential technology needs and scope.
Typical Activities and Products
• Review/identify any initial customer requirements or scope of work, which may include:
 >Mission
 >Science
 >Top-level system
• Identify and involve users and other stakeholders
 >Identify key stakeholders for each phase of the life cycle
 >Capture and baseline expectations as Needs, Goals, and Objectives (NGOs)
 >Define measures of effectiveness
• Develop and baseline the Concept of Operations
 >Identify and perform trade-offs and analyses of alternatives (AoA)
 >Perform preliminary evaluations of possible missions
• Identify risk classification
• Identify initial technical risks
• Identify the roles and responsibilities in performing mission objectives (i.e., technical team, flight, and 
ground crew) including training
• Develop plans
 >Develop preliminary SEMP
 >Develop and baseline Technology Development Plan
 >Define preliminary verification and validation approach
• Prepare program/project proposals, which may include:
 >Mission justification and objectives;
 >A ConOps that exhibits clear understanding of how the program’s outcomes will cost-effectively satisfy mission objectives;
 >High-level Work Breakdown Structures (WBSs);
 >Life cycle rough order of magnitude (ROM) cost, schedule, and risk estimates; and
 >Technology assessment and maturation strategies.
• Satisfy MCR entrance/success criteria from NPR 7123.1
Reviews
• MCR
• Informal proposal review233.0 NASA Program/Project Life Cycle
expectations for the project are gathered from them. 
If feasible concepts can be found, one or more may be selected to go into Phase A for further development. 
Typically, the system engineers are heavily involved 
in the development and assessment of the concept options. In projects governed by NPR 7120.5, the descope options define what the system can accom -
plish if the resources are not available to accomplish the entire mission. This could be in the form of fewer 
instruments, a less ambitious mission profile, accom -
plishing only a few goals, or using cheaper, less capa -
ble technology. Descope options can also reflect what 
the mission can accomplish in case a hardware fail -
ure results in the loss of a portion of the spacecraft 
architecture; for example, what an orbiter can accom -
plish after the loss of a lander. The success criteria are 
reduced to correspond with a descoped mission.
Descope options are developed when the NGOs 
or other stakeholder expectation documentation is 
developed. The project team develops a preliminary 
set of mission descope options as a gate product for the MCR, but these preliminary descope options are not baselined or maintained. They are kept in the documentation archive in case they are needed later 
in the life cycle.
It is important in Pre-Phase A to define an accurate 
group of stakeholders and users to help ensure that mission goals and operations concepts meet the needs and expectations of the end users. In addition, it is 
important to estimate the composition of the techni -
cal team and identify any unique facility or personnel 
requirements.
Advanced studies may extend for several years and 
are typically focused on establishing mission goals 
and formulating top-level system requirements and ConOps. Conceptual designs may be developed to demonstrate feasibility and support programmatic estimates. The emphasis is on establishing feasibility and desirability rather than optimality. Analyses and designs are accordingly limited in both depth and number of options, but each option should be eval -

uated for its implications through the full life cycle, i.e., through Operations and Disposal. It is important in Pre-Phase A to develop and mature a clear vision of what problems the proposed program will address, how it will address them, and how the solution will be feasible and cost-effective.
3.4 Project Phase A: Concept 
and Technology Development
The purpose of Phase A is to develop a proposed 
mission/system architecture that is credible and responsive to program expectations, requirements, 
and constraints on the project, including resources. 
During Phase A, activities are performed to fully develop a baseline mission concept, begin or assume responsibility for the development of needed tech -
nologies, and clarify expected reliance on human elements to achieve full system functionality or 
autonomous system development. This work, along 
with interactions with stakeholders, helps mature the mission concept and the program requirements on the project. Systems engineers are heavily involved during this phase in the development and assessment 
of the architecture and the allocation of requirements 
to the architecture elements.
In Phase A, a team—often associated with a program 
or informal project office—readdresses the mission concept first developed in Pre-Phase A to ensure that 
the project justification and practicality are sufficient 
to warrant a place in NASA’s budget. The team’s effort focuses on analyzing mission requirements and estab -
lishing a mission architecture. Activities become for -
mal, and the emphasis shifts toward optimizing the 
concept design. The effort addresses more depth and 
considers many alternatives. Goals and objectives are 243.0 NASA Program/Project Life Cycle
SPACE FLIGHT PHASE A:  
CONCEPT AND TECHNOLOGY DEVELOPMENT
Purpose
To determine the feasibility and desirability of a suggested new system and establish an initial baseline compatibility with NASA’s strategic plans. Develop final mission concept, system-level requirements, needed system technology developments, and program/project technical management plans.
• Review and update documents baselined in Pre-Phase A if needed
• Monitor progress against plans
• Develop and baseline top-level requirements and constraints including internal and external interfaces, 
integrated logistics and maintenance support, and system software functionality
• Allocate system requirements to functions and to next lower level
• Validate requirements
• Baseline plans
 >Systems Engineering Management Plan
 >Human Systems Integration Plan
 >Control plans such as the Risk Management Plan, Configuration Management Plan, Data Management Plan, Safety and Mission Assurance Plan, and Software Development or Management Plan (See NPR 7150.2)
 >Other crosscutting and specialty plans such as environmental compliance documentation, acquisition surveillance plan, contamination control plan, electromagnetic interference/electromagnetic compatibility control plan, reliability plan, quality control plan, parts management plan, logistics plan
• Develop preliminary Verification and Validation Plan
• Establish human rating plan and perform initial evaluations
• Develop and baseline mission architecture
 >Develop breadboards, engineering units or models identify and reduce high risk concepts
 >Demonstrate that credible, feasible design(s) exist
 >Perform and archive trade studies
 >Initiate studies on human systems interactions
• Initiate environmental evaluation/National Environmental Policy Act process
• Develop initial orbital debris assessment (NASA-STD-8719.14)
• Perform technical management
 >Provide technical cost estimate and range and develop system-level cost-effectiveness model
 >Define the WBS
 >Develop SOWs
 >Acquire systems engineering tools and models
(continued)253.0 NASA Program/Project Life Cycle
solidified, and the project develops more definition 
in the system requirements, top-level system architec -
ture, and ConOps. Conceptual designs and analyses 
(including engineering units and physical models, as 
appropriate) are developed and exhibit more engi -
neering detail than in Pre-Phase A. Technical risks are identified in more detail, and technology develop -
ment needs become focused. A Systems Engineering Management Plan (SEMP) is baselined in Phase A to 
document how NASA systems engineering require -
ments and practices of NPR 7123.1 will be addressed 
throughout the program life cycle.
In Phase A, the effort focuses on allocating func -
tions to particular items of hardware, software, and 
to humans. System functional and performance requirements, along with architectures and designs, become firm as system tradeoffs and subsystem tradeoffs iterate back and forth, while collaborating with subject matter experts in the effort to seek out 
more cost-effective designs. A method of determin -
ing life cycle cost (i.e., system-level cost-effectiveness 
model) is refined in order to compare cost impacts for each of the different alternatives. (Trade studies should precede—rather than follow—system design 
decisions.) Major products to this point include an 
accepted functional baseline for the system and its major end items. The project team conducts the secu -
rity categorization of IT systems required by NPR 2810.1 and Federal Information Processing Standard Publication (FIPS PUB) 199. The effort also pro -
duces various engineering and management plans to prepare for managing the project’s downstream pro -
cesses such as verification and operations.
3.5 Project Phase B:  
Preliminary Design and 
Technology Completion
The purpose of Phase B is for the project team to 
complete the technology development, engineering prototyping, heritage hardware and software assess -
ments, and other risk-mitigation activities identified in the project Formulation Agreement (FA) and the preliminary design. The project demonstrates that its planning, technical, cost, and schedule baselines developed during Formulation are complete and con -
sistent; that the preliminary design complies with its 
requirements; that the project is sufficiently mature 
to begin Phase C; and that the cost and schedule are adequate to enable mission success with acceptable risk. It is at the conclusion of this phase that the project and the Agency commit to accomplishing 
the project’s objectives for a given cost and schedule. 
For projects with a Life Cycle Cost (LCC) greater than $250 million, this commitment is made with the Congress and the U.S. Office of Management and Budget (OMB). This external commitment is the Agency Baseline Commitment (ABC). Systems  >Establish technical resource estimates
• Identify, analyze and update risks
• Perform required Phase A technical activities from NPR 7120.5 as applicable
• Satisfy Phase A reviews’ entrance/success criteria from NPR 7123.1
Reviews
• SRR
• MDR/SDR263.0 NASA Program/Project Life Cycle
SPACE FLIGHT PHASE B:  
PRELIMINARY DESIGN AND TECHNOLOGY COMPLETION
Purpose
To define the project in enough detail to establish an initial baseline capable of meeting mission needs. Develop system structure end product (and enabling product) requirements and generate a preliminary design for each system structure end product.
• Review and update documents baselined in previous phases
• Develop the preliminary design
 >Identify one or more feasible preliminary designs including internal and external interfaces
 >Perform analyses of candidate designs and report results
 >Conduct engineering development tests as needed and report results
 >Perform human systems integration assessments
 >Select a preliminary design solution
• Develop operations plans based on matured ConOps
 >Define system operations as well as Principal Investigator (PI)/contract proposal management, 
review, and access and contingency planning
• Report technology development results
• Update cost range estimate and schedule data (Note that after PDR changes are incorporated and costed, at KDP C this will turn into the Agency Baseline Commitment)
• Improve fidelity of models and prototypes used in evaluations
• Identify and update risks
• Develop appropriate level safety data package and security plan
• Develop preliminary plans
 >Orbital Debris Assessment
 >Decommissioning Plan
 >Disposal Plan
• Perform required Phase B technical activities from NPR 7120.5 as applicable
• Satisfy Phase B reviews’ entrance/success criteria from NPR 7123.1
Reviews
• PDR
• Safety review273.0 NASA Program/Project Life Cycle
engineers are involved in this phase to ensure the 
preliminary designs of the various systems will work together, are compatible, and are likely to meet the 
customer expectations and applicable requirements.
During Phase B, activities are performed to estab -
lish an initial project baseline, which (according to 
NPR 7120.5 and NPR 7123.1) includes “a formal flow down of the project-level performance require -

Reviews
• PDR
ments to a complete set of system and subsystem design specifications for both flight and ground ele -
ments” and “corresponding preliminary designs.” The technical requirements should be sufficiently detailed to establish firm schedule and cost estimates 
for the project. It also should be noted, especially for 
AO-driven projects, that Phase B is where the top-level requirements and the requirements flowed down to the next level are finalized and placed under con -
figuration control. While the requirements should be baselined in Phase A, changes resulting from the 
trade studies and analyses in late Phase A and early 
Phase B may result in changes or refinement to sys -
tem requirements.
It is important in Phase B to validate design decisions 
against the original goals and objectives and ConOps. 
All aspects of the life cycle should be considered, including design decisions that affect training, oper -
ations resource management, human factors, safety, habitability and environment, and maintainability and supportability.
The Phase B baseline consists of a collection of evolv -
ing baselines covering technical and business aspects 
of the project: system (and subsystem) requirements and specifications, designs, verification and opera -
tions plans, and so on in the technical portion of the baseline, and schedules, cost projections, and man -
agement plans in the business portion. Establishment of baselines implies the implementation of configura -
tion management procedures. (See 
Section 6.5 .)Phase B culminates in a series of PDRs, containing the system-level PDR and PDRs for lower level end items as appropriate. The PDRs reflect the succes -
sive refinement of requirements into designs. Design issues uncovered in the PDRs should be resolved 
so that final design can begin with unambiguous 
design-to specifications. From this point on, almost all changes to the baseline are expected to represent successive refinements, not fundamental changes. As noted in 
FIGURE 2.5-1 , significant design changes at 
and beyond Phase B become increasingly expensive.
3.6 Project Phase C:  
Final Design and Fabrication
The purpose of Phase C is to complete and docu -
ment the detailed design of the system that meets the detailed requirements and to fabricate, code, 
or otherwise realize the products. During Phase 
C, activities are performed to establish a complete design (product baseline), fabricate or produce hard -
ware, and code software in preparation for integra -
tion. Trade studies continue and results are used to validate the design against project goals, objectives, 
and ConOps. Engineering test units more closely 
resembling actual hardware are built and tested to establish confidence that the design will function in the expected environments. Human subjects repre -
senting the user population participate in operations 
evaluations of the design, use, maintenance, training 
procedures, and interfaces. Engineering specialty and crosscutting analysis results are integrated into the design, and the manufacturing process and controls are defined and valid. Systems engineers are involved in this phase to ensure the final detailed designs of 
the various systems will work together, are compati -
ble, and are likely to meet the customer expectations 
and applicable requirements. During fabrication, the systems engineer is available to answer questions and work any interfacing issues that might arise.283.0 NASA Program/Project Life Cycle
SPACE FLIGHT PHASE C: FINAL DESIGN AND FABRICATION
Purpose
To complete the detailed design of the system (and its associated subsystems, including its operations systems), fabricate hardware, and code software. Generate final designs for each system structure end product.
• Develop and document hardware and software detailed designs
 >Fully mature and define selected preliminary designs
 >Add remaining lower level design specifications to the system architecture
 >Perform development testing at the component or subsystem level
 >Fully document final design and develop data package
• Develop/refine and baseline plans
 >Interface definitions
 >Implementation plans
 >Integration plans
 >Verification and validation plans
 >Operations plans
• Develop/refine preliminary plans
 >Decommissioning and disposal plans, including human capital transition
 >Spares
 >Communications (including command and telemetry lists)
• Develop/refine procedures for
 >Refine integration
 >Manufacturing and assembly
 >Verification and validation
• Fabricate (or code) the product
• Monitor project progress against project plans
• Prepare launch site checkout and post launch activation and checkout
• Finalize appropriate level safety data package and updated security plan
• Identify opportunities for preplanned product improvement
• Refine orbital debris assessment
• Perform required Phase C technical activities from NPR 7120.5 as applicable
• Satisfy Phase C review entrance/success criteria from NPR 7123.1
(continued)293.0 NASA Program/Project Life Cycle
Reviews
• CDR
• PRR
• SIR
• Safety review
All the planning initiated back in Phase A for the 
testing and operational equipment, processes and analysis, integration of the crosscutting and engineer -
ing specialty analysis, and manufacturing processes and controls is implemented. Configuration manage -
ment continues to track and control design changes as detailed interfaces are defined. At each step in the successive refinement of the final design, correspond -
ing integration and verification activities are planned in greater detail. During this phase, technical param -
eters, schedules, and budgets are closely tracked to ensure that undesirable trends (such as an unexpected growth in spacecraft mass or increase in its cost) are recognized early enough to take corrective action. These activities focus on preparing for the CDR, Production Readiness Review (PRR) (if required), and the SIR.
Phase C contains a series of CDRs containing the sys-
tem-level CDR and CDRs corresponding to the dif -
ferent levels of the system hierarchy. A CDR for each end item should be held prior to the start of fabrica -
tion/production for hardware and prior to the start of coding of deliverable software products. Typically, the sequence of CDRs reflects the integration pro -
cess that will occur in the next phase; that is, from lower level CDRs to the system-level CDR. Projects, however, should tailor the sequencing of the reviews to meet the needs of the project. If there is a pro -
duction run of products, a PRR will be performed to ensure the production plans, facilities, and personnel are ready to begin production. Phase C culminates with an SIR. Training requirements and preliminary mission operations procedures are created and base -
lined. The final product of this phase is a product ready for integration.
3.7 Project Phase D:  
Integration and Test, Launch
The purpose of Phase D is to assemble, integrate, ver -
ify, validate, and launch the system. These activities 
focus on preparing for the Flight Readiness Review (FRR)/Mission Readiness Review (MRR). Activities include assembly, integration, verification, and vali -
dation of the system, including testing the flight sys -
tem to expected environments within margin. Other activities include updating operational procedures, rehearsals and training of operating personnel and crew members, and implementation of the logistics and spares planning. For flight projects, the focus of activities then shifts to prelaunch integration and launch. System engineering is involved in all aspects of this phase including answering questions, provid -
ing advice, resolving issues, assessing results of the verification and validation tests, ensuring that the V&V results meet the customer expectations and applicable requirements, and providing information to decision makers for go/no-go decisions.
The planning for Phase D activities was initiated 
in Phase A. For IT projects, refer to the IT Systems 
Engineering Handbook . The planning for the activ -
ities should be performed as early as possible since 303.0 NASA Program/Project Life Cycle
SPACE FLIGHT PHASE D:  
SYSTEM ASSEMBLY, INTEGRATION AND TEST, LAUNCH
Purpose
To assemble and integrate the system (hardware, software, and humans), meanwhile developing confidence that it will be able to meet the system requirements. Launch and prepare for operations. Perform system end product implementation, assembly, integration and test, and transition to use.
• Update documents developed and baselined in previous phases
• Monitor project progress against plans
• Integrate/assemble components according to the integration plans

Purpose
• Perform verification and validation on assemblies according to the V&V Plan and procedures
 >Perform system qualification verifications, including environmental verifications
 >Perform system acceptance verifications and validation(s) (e.g., end-to-end tests encompassing all 
elements; i.e., space element, ground system, data processing system)
 >Assess and approve verification and validation results
 >Resolve verification and validation discrepancies
 >Archive documentation for verifications and validations performed
 >Baseline verification and validation report
• Prepare and baseline
 >Operator’s manuals
 >Maintenance manuals
 >Operations handbook
• Prepare launch, operations, and ground support sites including training as needed
 >Train initial system operators and maintainers
 >Train on contingency planning
 >Confirm telemetry validation and ground data processing
 >Confirm system and support elements are ready for flight
 >Provide support to the launch and checkout of the system
 >Perform planned on-orbit operational verification(s) and validation(s)
• Document lessons learned. Perform required Phase D technical activities from NPR 7120.5
• Satisfy Phase D reviews’ entrance/success criteria from NPR 7123.1
Reviews
• Test Readiness Reviews (TRRs)
• System Acceptance Review (SAR) or pre-Ship Review
• ORR
(continued)313.0 NASA Program/Project Life Cycle
• FRR
• System functional and physical configuration audits
changes at this point can become costly. Phase D 
concludes with a system that has been shown to be capable of accomplishing the purpose for which it was created.
3.8 Project Phase E:  
Operations and Sustainment
The purpose of Phase E is to conduct the prime mission to meet the initially identified need and to maintain support for that need. The products of the phase are the results of the mission and performance of the system.
Systems engineering personnel continue to play a 
role during this phase since integration often overlaps with operations for complex systems. Some programs have repeated operations/flights which require con -
figuration changes and new mission objectives with each occurrence. And systems with complex sustain -
ment needs or human involvement will likely require evaluation and adjustments that may be beyond the scope of operators to perform. Specialty engineering disciplines, like maintainability and logistics servic -
ing, will be performing tasks during this phase as well. Such tasks may require reiteration and/or recur -
sion of the common systems engineering processes.
Systems engineering personnel also may be involved 
in in-flight anomaly resolution. Additionally, soft -
ware development may continue well into Phase E. For example, software for a planetary probe may be developed and uplinked while in-flight. Another example would be new hardware developed for space station increments.This phase encompasses the evolution of the system only insofar as that evolution does not involve major changes to the system architecture. Changes of that scope constitute new “needs,” and the project life cycle starts over. For large flight projects, there may be an extended period of cruise, orbit insertion, on-orbit assembly, and initial shakedown operations. Near the end of the prime mission, the project may apply for a mission extension to continue mission activities or attempt to perform additional mission objectives.
For additional information on systems engineering in 
Phase E, see 
Appendix T .
3.9 Project Phase F: Closeout
The purpose of Phase F is to implement the systems decommissioning and disposal planning and analyze any returned data and samples. The products of the phase are the results of the mission. The system engi -
neer is involved in this phase to ensure all technical information is properly identified and archived, to answer questions, and to resolve issues as they arise.
Phase F deals with the final closeout of the sys-
tem when it has completed its mission; the time at which this occurs depends on many factors. For a flight system that returns to Earth after a short mis-sion duration, closeout may require little more than de-integrating the hardware and returning it to its owner. On flight projects of long duration, closeout may proceed according to established plans or may begin as a result of unplanned events, such as fail -
ures. Refer to NASA Policy Directive (NPD) 8010.3, Notification of Intent to Decommission or Terminate Operating Space Systems and Terminate Missions, 323.0 NASA Program/Project Life Cycle
SPACE FLIGHT PHASE E: OPERATIONS AND SUSTAINMENT
Purpose
To conduct the mission and meet the initially identified need and maintain support for that need. Implement the mission operations plan.
• Conduct launch vehicle performance assessment. Commission and activate science instruments
• Conduct the intended prime mission(s)
• Provide sustaining support as planned
 >Implement spares plan
 >Collect engineering and science data
 >Train replacement operators and maintainers
 >Train the flight team for future mission phases (e.g., planetary landed operations)
 >Maintain and approve operations and maintenance logs
 >Maintain and upgrade the system
 >Identify and update risks
 >Address problem/failure reports
 >Process and analyze mission data
 >Apply for mission extensions, if warranted
• Prepare for deactivation, disassembly, decommissioning as planned (subject to mission extension)
• Capture lessons learned
• Complete post-flight evaluation reports
• Develop final mission report
• Perform required Phase E technical activities from NPR 7120.5
• Satisfy Phase E reviews’ entrance/success criteria from NPR 7123.1
Reviews
• Post-Launch Assessment Review (PLAR)
• Critical Event Readiness Review (CERR)
• Post-Flight Assessment Review (PFAR) (human space flight only)
• DR
• System upgrade review
• Safety review333.0 NASA Program/Project Life Cycle
for terminating an operating mission. Alternatively, 
technological advances may make it uneconomical to continue operating the system either in its current configuration or an improved one.
To limit space debris, NPR 8715.6, NASA Procedural 
Requirements for Limiting Orbital Debris, provides requirements for removing Earth-orbiting robotic satellites from their operational orbits at the end of their useful life. For Low Earth Orbit (LEO) mis -
sions, the satellite is usually deorbited. For small sat -
ellites, this is accomplished by allowing the orbit to slowly decay until the satellite eventually burns up in Earth’s atmosphere. Larger, more massive satel -
lites and observatories should be designed to demise or deorbit in a controlled manner so that they can be safely targeted for impact in a remote area of the ocean. The Geostationary (GEO) satellites at 35,790 km above the Earth cannot be practically deorbited, so they are boosted to a higher orbit well beyond the crowded operational GEO orbit.
In addition to uncertainty about when this part of 
the phase begins, the activities associated with safe closeout of a system may be long and complex and may affect the system design. Consequently, different options and strategies should be considered during the project’s earlier phases along with the costs and risks associated with the different options.
3.10 Funding: The Budget Cycle
For a description of the NASA Budget Cycle, refer to the NASA Expanded Guidance for Systems Engineering document found at 
web/se/doc-repository . See also Section 5.8 of NASA/
SP-2014-3705, NASA Space Flight Program and Project Management Handbook .PHASE F: CLOSEOUT
Purpose
To implement the systems decommissioning/disposal plan developed in Phase E and perform analyses of the returned data and any returned samples.
• Dispose of the system and supporting processes
• Document lessons learned
• Baseline mission final report
• Archive data
• Perform required Phase F technical activities from NPR 7120.5
• Satisfy Phase F reviews’ entrance/success criteria from NPR 7123.1
Reviews
• DRR343.0 NASA Program/Project Life Cycle
3.11 Tailoring and Customization 
of NPR 7123.1 Requirements
In this section, the term requirements  refers to the 
“shall” statements imposed from Agency direc -
tives. This discussion focuses on the tailoring of the 
requirements contained in NPR 7123.1.
3.11.1  Introduction
NASA policy recognizes the need to accommodate the 
unique aspects of each program or project to achieve mission success in an efficient and economical man -
ner. Tailoring is a process used to accomplish this.
NPR 7123.1 defines tailoring  as “the process used 
to seek relief from SE NPR  requirements  consistent 
with program  or project  objectives, allowable risk, 
and constraints .” Tailoring results in deviations or 
waivers (see NPR 7120.5, Section 3.5) to SE require -

Reviews
ments and is documented in the next revision of the 
SEMP (e.g., via the Compliance Matrix).
Since NPR 7123.1 was written to accommodate pro -
grams and projects regardless of size or complexity, 
the NPR requirements leave considerable latitude for interpretation. Therefore, the term “customization” is introduced and is defined as “the modification of recommended SE practices that are used to accom -
plish the SE requirements.” Customization does not 
require waivers or deviations, but significant custom -
ization should be documented in the SEMP.
Tailoring and customization are essential systems 
engineering tools that are an accepted and expected 
part of establishing the proper SE NPR require -
ments for a program or project. Although tailoring is 
expected for all sizes of projects and programs, small projects present opportunities and challenges that are different from those of large, traditional projects such as the Shuttle, International Space Station, Hubble 
Space Telescope, and Mars Science Laboratory.While the technical aspects of small projects are gen -
erally narrower and more focused, they can also be 
challenging when their objectives are to demonstrate advanced technologies or provide “one of a kind” capabilities. At the same time, their comparatively small budgets and restricted schedules dictate lean 
and innovative implementation approaches to proj -
ect management and systems engineering. Tailoring 
and customization allow programs and projects to be successful in achieving technical objectives within cost and schedule constraints. The key is effective tai -
loring that reflects lessons learned and best practices. Tailoring the SE requirements and customizing the SE best practices to the specific needs of the project helps to obtain the desired benefits while eliminating unnecessary overhead. To accomplish this, an accept -
able risk posture must be understood and agreed 
upon by the project, customer/stakeholder, Center 
management, and independent reviewers. Even with this foundation, however, the actual process of appro -
priately tailoring SE requirements and customizing NPR 7123.1 practices to a specific project can be 
complicated and arduous. Effective approaches and 
experienced mentors make the tailoring process for any project more systematic and efficient.
Chapter 6 of the NASA Software Engineering 
Handbook  provides guidance on tailoring SE require -
ments for software projects.
3.11.2  Criteria for Tailoring
NPR 8705.4, Risk Classification for NASA Payloads, is intended for assigning a risk classification to projects and programs. It establishes baseline criteria that enable 
users to define the risk classification level for NASA 
payloads on human or non-human-rated launch sys -
tems or carrier vehicles. It is also a starting point for understanding and defining criteria for tailoring.
The extent of acceptable tailoring depends on several char -
acteristics of the program/project such as the following:353.0 NASA Program/Project Life Cycle
1. Type of mission. For example, the requirements 
for a human space flight mission are much more 
rigorous than those for a small robotic mission.
2. Criticality of the mission in meeting the Agency 
Strategic Plan. Critical missions that absolutely must be successful may not be able to get relief 
from NPR requirements.
3. Acceptable risk level.  If the Agency and the 
customer are willing to accept a higher risk of 
failure, some NPR requirements may be waived.
4. National significance.  A project that has great 
national significance may not be able to get relief from NPR requirements.
5. Complexity.  Highly complex missions may 
require more NPR requirements in order to keep systems compatible, whereas simpler ones may 
not require the same level of rigor.
6. Mission lifetime.  Missions with a longer lifetime 
need to more strictly adhere to NPR require -
ments than short-lived programs/projects.
7. Cost of mission.  Higher cost missions may 
require stricter adherence to NPR requirements 
to ensure proper program/project control.
8. Launch constraints.  If there are several launch 
constraints, a project may need to be more fully compliant with Agency requirements.
3.11.3   Tailoring SE NPR Requirements 
Using the Compliance Matrix
NPR 7123.1 includes a Compliance Matrix 
(Appendix H.2) to assist programs and projects in verifying that they meet the specified NPR require -
ments. The Compliance Matrix documents the pro -
gram/project’s compliance or intent to comply with the requirements of the NPR or justification for tai -
loring. The Compliance Matrix can be used to assist in identifying where major customization of the way (e.g., formality and rigor) the NPR requirements will be accomplished and to communicate that cus -
tomization to the stakeholders. The tailoring pro -
cess (which can occur at any time in the program or project’s life cycle) results in deviations or waivers to the NPR requirements depending on the timing of the request. Deviations and waivers of the require -
ments can be submitted separately to the Designated Governing Authority or via the Compliance Matrix. 
The Compliance Matrix is attached to the Systems 
Engineering Management Plan (SEMP) when sub -
mitted for approval. Alternatively, if there is no stand-alone SEMP and the contents of the SEMP are incorporated into another document such as the 
project plan, the Compliance Matrix can be captured 
within that plan.
FIGURE 3.11-1  illustrates a notional tailoring process 
for a space flight project. Project management (such as the project manager/the Principal Investigator/
the task lead, etc.) assembles a project team to tailor 
the NPR requirements codified in the Compliance Matrix. To properly classify the project, the team (chief engineer, lead systems engineer, safety and mis -
sion assurance, etc.) needs to understand the building blocks of the project such as the needs, goals, and 
objectives as well as the appropriate risk posture.
Through an iterative process, the project team goes 
through the NPR requirements in the Compliance Matrix to tailor the requirements. A tailoring tool 
with suggested guidelines may make the tailoring 
process easier if available. Several NASA Centers including LaRC and MSFC have developed tools for use at their Centers which could be adapted for other Centers. Guidance from Subject Matter Experts (SMEs) should be sought to determine the 
appropriate amount of tailoring for a specific project. 363.0 NASA Program/Project Life Cycle
The Compliance Matrix provides rationales for each 
of the NPR requirements to assist in understanding. Once the tailoring is finalized and recorded in the Compliance Matrix with appropriate rationales, the requested tailoring proceeds through the appropriate governance model for approval.
3.11.4   Ways to Tailor a SE 
Requirement
Tailoring often comes in three areas:
1. Eliminating a requirement that does not apply to 
the specific program/project.
2. Eliminating a requirement that is overly bur -
densome (i.e., when the cost of implementing the requirement adds more risk to the project by diverting resources than the risk of not comply -
ing with the requirement).Inputs Outputs
Project 
Needs, Goals, 
Objectives
Tailoring  
Tool(s)
Approved 
Compliance Matrix 
Attached to SEMP or 
Project P lanCenter-level
Program Office
Engine ering/Projects Direct orate
PM
S&MA
CE
LSERisk  
PostureReview/
Approve
Review/Approve
Final ize/
Update 
Project-
Specific 
Tailoring 
and Capt ure 
Waiver 
Rationales
Advi sory 
Teams as 
NecessarySuggest 
Tailoring N
N
N YYY
Project Team 
Review 
and Refine 
TailoringReview/Approve
FIGURE 3.11-1  No tional Space Flight Products Tailoring Process
3. Scaling the requirement in a manner that bet -
ter balances the cost of implementation and the 
project risk.
Customizing SE practices can include the following:
1. Adjusting the way each of the 17 SE processes is implemented.
2. Adjusting the formality and timing of reviews.
3.11.4.1   Non-Applicable NPR Requirements
Each requirement in NPR 7123.1 is assessed for applicability to the individual project or program. For example, if the project is to be developed com -
pletely in-house, the requirements of the NPR’s Chapter 4 on contracts would not be applicable. If a system does not contain software, then none of the NPR requirements for developing and maintaining software would be applicable.373.0 NASA Program/Project Life Cycle
3.11.4.2   Adjusting the Scope
Depending on the project or program, some relief on 
the scope of a requirement may be appropriate. For example, although the governing project management 
directive (e.g., NPR 7120.5, 7150.2, 7120.7, 7120.8) 
for a program/project may require certain documents to be standalone, the SE NPR does not require any additional stand-alone documents. For small proj -

ects, many of the plans can be described in just a few paragraphs or pages. In these types of projects, any 
NPR requirements stating that the plans need to be 
stand-alone document would be too burdensome. In these cases, the information can simply be written and included as part of the project plan or SEMP. If the applicable project management directive (e.g., 
NPR 7120.5 or NPR 7120.8) requires documents to 
be stand-alone, a program/project waiver/deviation is needed. However, if there is no requirement or Center expectation for a stand-alone document, a project can customize where that information is recorded and no waiver or deviation is required. Capturing where this 
information is documented within the systems engi -
neering or project management Compliance Matrix 
would be useful for clarity.
3.11.4.3   Formality and Timing of Reviews
The governing project management directive iden -
tifies the required or recommended life cycle for the specific type of program/project. The life cycle 
defines the number and timing of the various 
reviews; however, there is considerable discretion concerning the formality of the review and how to conduct it. NPR 7123.1, Appendix G, provides extensive guidance for suggested review entrance and success criteria. It is expected that the program/
project will customize these criteria in a manner 
that makes sense for their program/project. The SE NPR does not require a waiver/deviation for this customization; however, departures from review ele -
ments required by other NPRs need to be addressed 
by tailoring those documents.If a program/project decides it does not need one of 
the required reviews, a waiver or deviation is needed. 
However, the SE NPR does not specify a minimum 
amount of spacing for these reviews. A small project may decide to combine the SRR and the SDR (or Mission Definition Review (MDR)) for example. As long as the intent for both reviews is accomplished, 
the SE NPR does not require a waiver or deviation. (Note that even though the SE NPR does not require it, a waiver or deviation may still be required in the governing project management NPR.) This customi -
zation and/or tailoring should be documented in the Compliance Matrix and/or the review plan or SEMP.
Unless otherwise required by the governing project 
management directives, the formality of the review can be customized as appropriate for the type of program/project. For large projects, it might be 
appropriate to conduct a very formal review with a 
formal Review Item Discrepancy (RID)/Request for Action (RFA) process, a summary, and detailed  
presentations to a wide audience including boards and  
pre-boards over several weeks. For small projects, that same review might be done in a few hours across 
a tabletop with a few stakeholders and with issues  
and actions simply documented in a word or 
PowerPoint document.
The NASA Engineering Network Systems 
https://nen.nasa.gov/web/se  includes document tem -
plates for milestone review presentations required by 
the NASA SE process.
Customization
TABLE 3.11-1  shows an example of the types of mis -
sions that can be defined based on a system that 
breaks projects into various types ranging from a very 
complex type A to a much simpler type F. When tai -
loring a project, the assignment of specific projects to 383.0 NASA Program/Project Life Cycle
TABLE 3.11-1  Example of Program/Project Types
Criteria Type A Type B Type C Type D Type E Type F
Description of the 
Types of MissionHuman Space Flight or Very Large Science/Robotic MissionsNon-Human Space Flight or Science/Robotic MissionsSmall Science or Robotic MissionsSmaller Science or Technology Missions (ISS payload)Suborbital or Aircraft or Large Ground based MissionsAircraft or Ground based technology demonstrations
Priority (Criticality to Agency Strategic Plan) and Acceptable Risk LevelHigh priority, very low (minimized) riskHigh priority,  
low riskMedium priority, medium riskLow priority,  
high riskLow priority,  
high riskLow to very low priority, high risk
National Significance Very high High Medium Medium to Low Low Very Low
Complexity Very high to high High to Medium Medium to Low Medium to Low Low Low to Very Low
Mission Lifetime (Primary Baseline Mission)Long. >5 years Medium. 2–5 yearsShort. <2 years Short. <2 years N/A N/A
Cost Guidance  
(estimate LCC)High 
(greater than ~$1B)High to Medium (~$500M–$1B)Medium to Low (~$100M–$500M)Low 
(~$50M–$100M) (~$10–50M) (less than $10–15M)
Launch Constraints Critical Medium Few Few to none Few to none N/A
Alternative Research 
Opportunities 
or Re-flight OpportunitiesNo alternative 
or re-flight 
opportunitiesFew or no 
alternative 
or re-flight opportunitiesSome or few 
or re-flight opportunitiesSignificant 
or re-flight opportunities
Achievement of Mission Success CriteriaAll practical 
measures are taken to achieve minimum risk to mission success. The highest assurance standards are used.Stringent assurance standards with only minor compromises in application to maintain a low risk to mission success.Medium risk of not achieving mission success may be acceptable. Reduced assurance standards are permitted.Medium or significant risk of not achieving mission success is permitted. Minimal assurance standards are permitted.Significant risk of not achieving mission success is permitted. Minimal assurance standards are permitted.Significant risk of not achieving mission success is permitted. Minimal assurance standards are permitted.
Examples HST, Cassini, JIMO, JWST, MPCV, SLS, ISSMER, MRO, Discovery payloads, ISS Facility Class payloads, Attached ISS payloadsESSP, Explorer payloads, MIDES, ISS complex subrack payloads, PA-1,  
ARES 1-X, MEDLI, CLARREO,  
SAGE III, CalipsoSPARTAN, GAS Can, technology demonstrators, simple ISS, express middeck and subrack payloads, SMEX, MISSE-X, EV-2
IRVE-2, IRVE -3 , 
HiFIRE, HyBoLT, ALHAT, STORRM, Earth Venture IDAWNAir, InFlame, Research, technology demonstrations393.0 NASA Program/Project Life Cycle
TABLE 3.11-2  Example of Tailoring NPR 7120  .5 Re quired Project Products
Type A Type B Type C Type D Type E Type F
Example Project Technical Products
Concept 
DocumentationFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Mission, Spacecraft, Ground, and Payload ArchitecturesFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Project-Level, System and Subsystem RequirementsFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Design DocumentationFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Operations Concept Fully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Technology Readiness Assessment DocumentationFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Human Systems Integration PlanFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Heritage Assessment DocumentationFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Safety Data PackagesFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
ELV Payload Safety Process DeliverablesFully CompliantFully CompliantFully CompliantFully CompliantFully CompliantNot Applicable
 Verification and Validation ReportFully CompliantFully CompliantFully 
CompliantTailor Tailor Tailor
Operations HandbookFully CompliantFully CompliantFully CompliantTailor Tailor Not Applicable
End of Mission Plans Fully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Mission Report Fully CompliantFully CompliantTailor Tailor Tailor Tailorparticular types should be viewed as guidance, not as 
rigid characterization. Many projects will have char -
acteristics of multiple types, so the tailoring approach may permit more tailoring for those aspects of the project that are simpler and more open to risk and less tailoring for those aspects of the project where complexity and/or risk aversion dominate. These tailoring criteria and definitions of project “types” may vary from Center to Center and from Mission Directorate to Mission Directorate according to what is appropriate for their missions. 
TABLE 3.11-2  shows 
an example of how the documentation required of 
(continued)403.0 NASA Program/Project Life Cycle
Example Project Plan Control Plans
Risk Management 
PlanFully CompliantFully CompliantFully CompliantTailor Tailor Not Applicable
Technology Development planFully CompliantFully CompliantFully CompliantFully CompliantNot ApplicableNot Applicable
Systems Engineering Management PlanFully CompliantFully CompliantFully CompliantTailor Tailor Tailor
Software Management planFully CompliantFully CompliantTailor Tailor Tailor Tailor

Verification and Validation PlanFully CompliantFully CompliantTailor Tailor Tailor Tailor
Review Plan Fully 
CompliantFully CompliantFully CompliantTailor Tailor Tailor
Integrated Logistics 
Support PlanFully CompliantFully CompliantFully CompliantTailor Tailor Not Applicable
Science Data Management PlanFully CompliantFully CompliantFully CompliantTailor Tailor Not Applicable
Integration Plan Fully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Configuration Management PlanFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Technology Transfer (formerly Export) Control PlanFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Lessons Learned PlanFully CompliantFully CompliantFully CompliantFully CompliantTailor Tailor
Human Rating Certification PackageFully CompliantNot ApplicableNot ApplicableNot ApplicableNot ApplicableNot Applicable
a program/project might also be tailored or custom -
ized. The general philosophy is that the simpler, less 
complex projects should require much less documen -
tation and fewer formal reviews. Project products should be sensibly scaled.
3.11.6   Approvals for Tailoring
Deviations and waivers of the requirements for the SE NPR can be submitted separately to the require -
ments owners or in bulk using the appropriate 
Compliance Matrix found in NPR 7123.1 Appendix H. If it is a Center that is requesting tailoring of the 
NPR requirements for standard use at the Center, Appendix H.1 is completed and submitted to the OCE for approval upon request or as changes to the Center processes occur. If a program/project whose 
responsibility has been delegated to a Center is seek -
ing a waiver/deviation from the NPR requirements, 
the Compliance Matrix in Appendix H.2 is used. In these cases, the Center Director or designee will approve the waiver/deviation.413.0 NASA Program/Project Life Cycle
The result of this tailoring, whether for a Center or 
for a program/project, should also be captured in the next revision of the SEMP along with support -
ing rationale and documented approvals from the requirement owner. This allows communication of the approved waivers/deviations to the entire project team as well as associated managers. If an indepen -
dent assessment is being conducted on the program/project, this also allows appropriate modification of expectations and assessment criteria. 
TABLE 3.11-3 
provides some examples of tailoring captured within the H.2 Compliance Matrix.
TABLE 3.11-3  Example Use  of a Compliance Matrix
Req
IDSE NPR 
Sectio
nRequirement 
StatementRationale Req. OwnerComply? Justification
SE-05 2.1.5.2 For those 
requirements owned by Center 
Directors, the 
technical team 
shall complete the 
in Appendix H.2  
and include it in the 
SEMP.For programs and projects, the 
Compliance Matrix in Appendix H.2 is filled out showing that the 
program/project is compliant with the requirements of this NPR (or a particular Center’s implementation of NPR 7123.1, whichever is applicable) or any tailoring thereof is identified and approved by the 
Center Director or designee as part 
of the program/project SEMP.CD Fully 
Compliant
SE-06 2.1.6.1 The DGA shall 
approve the 
SEMP, waiver  
authorizations, and other key technical 
documents to 
ensure independent 
assessment  of 
technical content.The DGA, who is often the TA, 
provides an approval of the SEMPs, waivers to technical requirements 
and other key technical document 
to provide assurance of the 
applicability and technical quality of the products.CD Fully 
Complaint
SE-24 4.2.1 The NASA technical 
team  shall  define 
the engineering activities for the 
periods before 
contract  award , 
during contract 
performance , and 
upon contract completion in the 
SEMP.It is important for both the 
government and contractor 
technical teams to understand what activities will be handled by which organization throughout the 
product life cycle. The contractor(s) will typically develop a SEMP or its 
equivalent to describe the technical 
activities in their portion of the 
project, but an overarching SEMP 
is needed that will describe all 
technical activities across the life 
cycle whether contracted or not.CD Not ApplicableProject is 
conducted 
entirely 
in-house and 
therefore there are no 
contracts 
involved423.0 NASA Program/Project Life Cycle
NASA SYSTEMS ENGINEERING HANDBOOK43
NASA SYSTEMS ENGINEERING HANDBOOK4.0System Design Processes
This chapter describes the activities in the system 
design processes listed in FIGURE 2.1-1 . The chap -
ter is separated into sections corresponding to pro -
cesses 1 to 4 listed in FIGURE 2.1-1 . The tasks within 
each process are discussed in terms of inputs, activ -
ities, and outputs. Additional guidance is provided 
using examples that are relevant to NASA  projects.
The system design processes are interdependent, highly iterative and recursive processes resulting in a validated set of requirements and a design solution that satisfies a set of stakeholder expectations. There are four system design processes: developing stake -
holder expectations, technical requirements, logical decompositions, and design solutions.
FIGURE 4.0-1  illustrates the recursive relationship 
among the four system design processes. These pro -
cesses start with a study team collecting and clarifying the stakeholder expectations, including the mission objectives, constraints, design drivers, operational objectives, and criteria for defining mission success. This set of stakeholder expectations and high-level requirements is used to drive an iterative design loop where a straw man architecture/design, the concept of operations, and derived requirements are devel -
oped. These three products should be consistent with each other and will require iterations and design deci -
sions to achieve this consistency. Once consistency is achieved, analyses allow the project team to validate the proposed design against the stakeholder expecta -
tions. A simplified validation asks the questions: Will the system work as expected? Is the system achiev -
able within budget and schedule constraints? Does the system provide the functionality and fulfill the operational needs that drove the project’s funding approval? If the answer to any of these questions is no, then changes to the design or stakeholder expec -
tations will be required, and the process starts again. This process continues until the system—architec -
ture, ConOps, and requirements—meets the stake -
holder expectations.
The depth of the design effort should be sufficient 
to allow analytical verification of the design to the requirements. The design should be feasible and cred -
ible when judged by a knowledgeable independent review team and should have sufficient depth to sup -
port cost modeling and operational assessment.
Once the system meets the stakeholder expectations, 
the study team baselines the products and prepares for the next phase. Often, intermediate levels of decomposition are validated as part of the process. In 444.0 System Design Processes
Iterate	Requirements
Program	
AuthorityNeeds,	
Goals	and	
Constraints
Success	
CriteriaDevelop	
ConOpsStakeholder	ExpectationsIterate	ConOps
Iterate	
Expectations
Design	Solution	DefinitionDerived	and	
Allocated	
Requirements
•Functional
•Performance
•Interface
•Operational
•Safety
•“ilities”Validate
Req.	SetReq.	Meet	
ConOps?Inconsistencies	 -Iterate
GoodYesRequirements	Definition
No	-Iterate
Compare EvaluateSuccess	
CriteriaIterate
Lowest	
Level?No	–Recursive	Cycle
To	Product	
Realization	
ProcessesLogical	
Decomposition
•Functional	Flow
•Temporal	Flow
•Behavioral
•Data	Flow
•States	and	ModesDevelop	
ArchitectureDevelop	
Design
ConOps
FIGURE 4.0 -1  Interrelationships among the System Design Processes
SYSTEM DESIGN KEYS
• Successfully understanding and defining the mission objectives and the concept of operations are keys 
to capturing the stakeholder expectations, which will translate into quality requirements and operational efficiencies over the life cycle of the project.
• Complete and thorough requirements traceability is a critical factor in successful validation of requirements.
• Clear and unambiguous requirements will help avoid misunderstanding when developing the overall system and when making major or minor changes.
• Document all decisions made during the development of the original design concept in the technical data package. This will make the original design philosophy and negotiation results available to assess future proposed changes and modifications against.
• The validation of a design solution is a continuing recursive and iterative process during which the design solution is evaluated against stakeholder expectations.454.0 System Design Processes
the next level of decomposition, the baselined derived 
(and allocated) requirements become the set of high-level requirements for the decomposed elements and 
the process begins again. These system design pro -
cesses are primarily applied in Pre-Phase A and con -
tinue through Phase C.
The system design processes during Pre-Phase A 
focus on producing a feasible design that will lead

focus on producing a feasible design that will lead 
to Formulation approval. During Phase A, alterna -
tive designs and additional analytical maturity are 
pursued to optimize the design architecture. Phase B results in a preliminary design that satisfies the approval criteria. During Phase C, detailed, build-to 
designs are completed.
This is a simplified description intended to demon -
strate the recursive relationship among the system 
design processes. These processes should be used as guidance and tailored for each study team depending 
on the size of the project and the hierarchical level 
of the study team. The next sections describe each of the four system design processes and their associated products for a given NASA mission.
4.1  Stakeholder Expectations 
The Stakeholder Expectations Definition Process is 
the initial process within the SE engine that estab -
lishes the foundation from which the system is 
designed and the product is realized. The main pur -
pose of this process is to identify who the stakehold -
ers are and how they intend to use the product. This 
is usually accomplished through use-case scenarios (sometimes referred to as Design Reference Missions (DRMs)) and the ConOps.4.1.1 Process Description
FIGURE 4.1-1  provides a typical flow diagram for the 
Stakeholder Expectations Definition Process and identifies typical inputs, outputs, and activities to 
consider in defining stakeholder expectations.
4.1.1.1  Inputs
Typical inputs needed for the Stakeholder Expectations 
Definition Process include the following:
• Initial Customer Expectations: These are the 
needs, goals, objectives, desires, capabilities, and other constraints that are received from the cus-
tomer for the product within the product layer. 
For the top-tier products (final end item), these are the expectations of the originating customer who requested the product. For an end product within the product layer, these are the expectations of the recipient of the end item when transitioned.
• Other Stakeholder Expectations: These are the 
expectations of key stakeholders other than the customer. For example, such stakeholders may 
be the test team that will be receiving the transi -
tioned product (end product and enabling prod -
ucts) or the trainers that will be instructing the 
operators or managers that are accountable for the product at this layer.
• Customer Flow-down Requirements: These are 
any requirements that are being flowed down or allocated from a higher level (i.e., parent require -
ments). They are helpful in establishing the expec-tations of the customer at this layer.
4.1.1.2  Process Activities
4.1.1.2.1  Identify Stakeholders
A “stakeholder” is a group or individual that is affected by or has a stake in the product or project. The key players for a project/product are called the 
key stakeholders. One key stakeholder is always the 464.0 System Design Processes
“customer.” The customer may vary depending on 
where the systems engineer is working in the PBS. For example, at the topmost level, the customer may be the person or organization that is purchasing the product. For a systems engineer working three or four levels down in the PBS, the customer may be the leader of the team that takes the element and inte -
grates it into a larger assembly. Regardless of where the systems engineer is working within the PBS, it is important to understand what is expected by 
the customer.Customer F low-down 
RequirementsInitial Customer
Expectations 
Enabling Product
Support StrategiesConcept of Operations
Measures of Effectiveness Validated Stakeholder
Other Stakeholder
Expectations From Project
  Establish list of stakeholders
Define stakeholder expec tations in acceptable
statements 
Validate that deﬁned expec tation statements 
reﬂect bidirectional traceabilityElicit stakeholder expectations
Establish operations concept and support
strategies
Analyze expectation statements for measures 
of effectiveness
Baseline stakeholder expect ationsObtain stakeholder commitments to the 
validated set of expectations
Capture work products from 
stakeholder expectations activitiesTo Technical Requirements 
Definition and Technical Data 
Management ProcessesTo Technical Requirements 
Definition and Configuration 
Management ProcessesTo Technical 
Requirements Definition and 
Requirements and Interface 
Management Processes
FIGURE 4.1 -1 Stakeh older Expectations Definition Process
Other interested parties are those who affect the project by providing broad, overarching constraints within which the customers’ needs should be achieved. These parties may be affected by the result -
ing p
roduct, the manner in which the product is 
used, or have a responsibility for providing life cycle support services. Examples include Congress, advi -
sory planning teams, program managers, maintain -
ers, and mission partners. It is important that the list of stakeholders be identified early in the process, as well as the primary stakeholders who will have the most significant influence over the project.
The customer and users of the system are usually 
easy to identify. The other key stakeholders may be more difficult to identify and they may change depending on the type of the project and the phase the project is in. 
TABLE 4.1-1  provides some 474.0 System Design Processes
examples of stakeholders in the life cycle phase that 
should be considered.
4.1.1.2.2  Understand Stakeholder Expectations
Thoroughly understanding the customer and other key stakeholders’ expectations for the project/prod -
uct is one of the most important steps in the systems engineering process. It provides the foundation upon which all other systems engineering work depends. It helps ensure that all parties are on the same page and that the product being provided will satisfy the cus -
tomer. When the customer, other stakeholders, and the systems engineer mutually agree on the func -
tions, characteristics, behaviors, appearance, and performance the product will exhibit, it sets more realistic expectations on the customer’s part and helps prevent significant requirements creep later in the life cycle.
Through interviews/discussions, surveys, marketing 
groups, e-mails, a Statement of Work (SOW), an initial set of customer requirements, or some other means, stakeholders specify what is desired as an end state or as an item to be produced and put bounds on the achievement of the goals. These bounds may TABLE 4.1-1  Stak eholder Identification throughout the Life Cycle
Life-Cycle Stage Example Stakeholders
Pre-Phase A NASA Headquarters, NASA Centers, Presidential Directives, NASA advisory committees, the 
National Academy of Sciences
Phase A Mission Directorate, customer, potential users, engineering disciplines, safety organization
Phase B Customer, engineering disciplines, safety, crew, operations, logistics, production facilities, suppliers, principle investigators
Phase C Customer, engineering disciplines, safety, crew, operations, logistics, production facilities, suppliers, principle investigators
Phase D Customer, engineering disciplines, safety, crew, operations, training, logistics, verification team, Flight Readiness Board members
Phase E Customer, system managers, operations, safety, logistics, sustaining team, crew, principle investigators, users
Phase F Customer, NASA Headquarters, operators, safety, planetary protection, public
encompass expenditures (resources), time to deliver, 
life cycle support expectations, performance objec -
tives, operational constraints, training goals, or other less obvious quantities such as organizational needs or geopolitical goals. This information is reviewed, summarized, and documented so that all parties can come to an agreement on the expectations.
FIGURE 4.1-2  shows the type of information needed 
when defining stakeholder expectations and depicts how the information evolves into a set of high-level requirements. The yellow lines depict validation paths. Examples of the types of information that would be defined during each step are also provided.
Defining stakeholder expectations begins with 
the mission authority  and strategic objectives  that 
the mission is meant to achieve. Mission authority changes depending on the category of the mission. For example, science missions are usually driven by NASA Science Mission Directorate strategic plans, whereas the exploration missions may be driven by a Presidential directive. Understanding the objectives of the mission helps ensure that the project team is working toward a common vision. These goals and 484.0 System Design Processes
objectives form the basis for developing the mission, 
so they need to be clearly defined and articulated.
The project team should also identify the constraints  
that may apply. A “constraint” is a condition that is to 
be met. Sometimes a constraint is dictated by external factors such as orbital mechanics, an existing system that must be utilized (external interface), a regu -

latory restriction, or the state of technology; some -
times constraints are the result of the overall budget environment. Concepts of operation and constraints also need to be included in defining the stakeholder expectations. These identify how the system should be operated to achieve the mission objectives.
NOTE:
 It is extremely important to involve stake -
holders in all phases of a project. Such involvement 
should be built in as a self-correcting feedback loop that will significantly enhance the chances of mis -
sion success. Involving stakeholders in a project builds confidence in the end product and serves as a validation and acceptance with the target audience.Mission 
Goals
Operational Drivers Measurements Mission Drivers
ExplorationsMission 
ObjectivesOperational 
ObjectivesSuccess
CriteriaDesign
Drivers
• Agency Strategic
  Plans• Announcements   of Opportunity• Road Maps• Directed Missions• Science Objectives• Exploration   Objectives• Technology  Demonstration   Objectives• Technology   Development  Objectives• Programmatic  Objectives• Integration and  Test• Launch• On-Orbit• Transfer• Surface• Science Data  Distribution• Maintenance• Logistics• Etc.• Launch Date• Mission Duration• Orbit• Cost Constraints• Etc.• What  measurements?• How well?
• What
  explorations?• What goals?
FIGURE 4.1 -2 Inf ormation Flow for Stakeholder Expectations
In identifying the full set of expectations, the systems 
engineer will need to interact with various commu -
nities, such as those working in the areas of orbital debris, space asset protection, human systems inte -
gration, quality assurance, and reliability. Ensuring that a complete set of expectations is captured will help prevent “surprise” features from arising later in the life cycle. For example, space asset protection may require additional encryption for the forward link commands, additional shielding or filtering for RF systems, use of a different frequency, or other design changes that might be costly to add to a system that has already been developed.
4.1.1.2.3  Identify Needs, Goals, and Objectives
In order to define the goals and objectives, it is nec -
essary to elicit the needs, wants, desires, capabilities, external interfaces, assumptions, and constraints from the stakeholders. Arriving at an agreed-to set of goals and objectives can be a long and arduous task. Proactive iteration with the stakeholders throughout the systems engineering process is the way that all par -
ties can come to a true understanding of what should be done and what it takes to do the job. It is important 494.0 System Design Processes
to know who the primary stakeholders are and who 
has the decision authority to help resolve conflicts.
Needs, Goals, and Objectives (NGOs) provide a 
mechanism to ensure that everyone (implementer, customer, and other stakeholders) is in agreement at the beginning of a project in terms of defining the problem that needs to be solved and its scope. NGOs are not contractual requirements or designs.
Needs are defined in the answer to the question 
“What problem are we trying to solve?” Goals address what must be done to meet the needs; i.e., what the customer wants the system to do. Objectives 
expand on the goals and provide a means to docu -
ment specific expectations. (Rationale should be pro -
vided where needed to explain why the need, goal, 
or objective exists, any assumptions made, and any other information useful in understanding or man -
aging the NGO.)
Well-written NGOs provide clear traceability from 
the needs, then to the goals, and then to objectives. For example, if a given goal does not support a need, or an objective does not support a goal, it should not 
be part of the integrated set of NGOs. This traceabil -
ity helps ensure that the team is actually providing 
what is needed.
The following definitions (source: Applied Space 
Systems Engineering  edited by Larson, Kirkpatrick, 
Sellers, Thomas, and Verma) are provided to help the 
reader interpret the NGOs contained in this product.
• Need:  A single statement that drives everything 
else. It should relate to the problem that the system is supposed to solve but not be the solution. The 
need statement is singular. Trying to satisfy more 
than one need requires a trade between the two, which could easily result in failing to meet at least one, and possibly several, stakeholder expectations.• Goals:  An elaboration of the need, which con -
stitutes a specific set of expectations for the sys -
tem. Goals address the critical issues identified 
during the problem assessment. Goals need not 
be in a quantitative or measurable form, but they should allow us to assess whether the system has 
achieved  them.
• Objectives: Specific target levels of outputs the 
system must achieve. Each objective should relate to a particular goal. Generally, objectives should 
meet four criteria. (1) They should be specific 
enough to provide clear direction, so developers, customers, and testers will understand them. They should aim at results and reflect what the system needs to do but not outline how to implement the solution. (2) They should be measurable, quantifi -
able, and verifiable. The project needs to monitor the system’s success in achieving each objective. (3) They should be aggressive but attainable, challenging but reachable, and targets need to be realistic. Objectives “To Be Determined” (TBD) 
may be included until trade studies occur, oper -
ations concepts solidify, or technology matures. 
Objectives need to be feasible before require -
ments are written and systems designed. (4) They should be results-oriented focusing on desired outputs and outcomes, not on the methods used 
to achieve the target (what, not how). It is import -
ant to always remember that objectives are not 
requirements. Objectives are identified during pre-Phase A development and help with the even -
tual formulation of a requirements set, but it is the 
requirements themselves that are contractually 
binding and will be verified against the “as-built” system design.
These stakeholder expectations are captured and are considered as initial until they can be further refined 
through development of the concept of operations 
and final agreement by the stakeholders.504.0 System Design Processes
4.1.1.2.4   Establish Concept of Operations and Support 
Strategies
After the initial stakeholder expectations have 
been established, the development of a Concept of Operations (ConOps) will further ensure that the 
technical team fully understands the expectations 
and how they may be satisfied by the product, and that understanding has been agreed to by the stake -
holders. This may lead to further refinement of the initial set of stakeholder expectations if gaps or ambig -
uous statements are discovered. These scenarios and 
concepts of how the system will behave provide an 
implementation-free understanding of the stakehold -
ers’ expectations by defining what is expected with -
out addressing how (the design) to satisfy the need. It captures required behavioral characteristics and 
the manner in which people will interact with the 
system. Support strategies include provisions for fab -
rication, test, deployment, operations, sustainment, 
and disposal.
The ConOps is an important component in captur -
ing stakeholder expectations and is used in defin -
ing requirements and the architecture of a project. 
It stimulates the development of the requirements 
and architecture related to the user elements of the system. It serves as the basis for subsequent defini -
tion documents such as the operations plan, launch and early orbit plan, and operations handbook, and it provides the foundation for the long-range opera -
tional planning activities such as operational facili -
ties, staffing, and network scheduling.
The ConOps is an important driver in the system 
requirements and therefore should be considered early 
in the system design processes. Thinking through the 
ConOps and use cases often reveals requirements and design functions that might otherwise be overlooked. For example, adding system requirements to allow for communication during a particular phase of a mis -
sion may require an additional antenna in a specific location that may not be required during the nominal mission. The ConOps should include scenarios for all 
significant operational situations, including known 
off-nominal situations. To develop a useful and complete set of scenarios, important malfunctions and degraded-mode operational situations should be considered. The ConOps is also an important aide to characterizing life cycle staffing goals and function 
allocation between humans and systems. In walking 
through the accomplishment of mission objectives, it should become clear when decisions need to be made as to what the human operators are contributing vs. what the systems are responsible for delivering.

The ConOps should consider all aspects of opera -
tions including nominal and off-nominal operations 
during integration, test, and launch through dis-posal. Typical information contained in the ConOps includes a description of the major phases; operation 
timelines; operational scenarios and/or DRM (see 
FIGURE 4.1-3  for an example of a DRM); fault man -
agement strategies, description of human interaction 
and required training, end-to-end communications 
strategy; command and data architecture; opera -
tional facilities; integrated logistic support (resup -
ply, maintenance, and assembly); staffing levels and 
required skill sets; and critical events. The operational scenarios describe the dynamic view of the systems’ operations and include how the system is perceived 
to function throughout the various modes and mode 
transitions, including interactions with external inter -
faces, response to anticipated hazard and faults, and during failure mitigations. For exploration missions, multiple DRMs make up a ConOps. The design and 
performance analysis leading to the requirements 
should satisfy all of them.
Additional information on the development of the 
ConOps is discussed in Section 4.1.2.1 of the NASA Expanded Guidance for Systems Engineering docu -
ment found 
https://nen.nasa.gov/web/se/doc-repository . 514.0 System Design Processes
CONCEPT OF OPERATIONS VS. OPERATIONS CONCEPT
Concept of Operations
Developed early in Pre-Phase A by the technical team, describes the overall high-level concept of how the system will be used to meet stakeholder expectations, usually in a time sequenced manner. It describes the system from an operational perspective and helps facilitate an understanding of the system goals. It stimulates the development of the requirements and architecture related to the user elements of the system. 
It serves as the basis for subsequent definition documents and provides the foundation for the long-range 
operational planning activities.
Operations Concept
A description of how the flight system and the ground system are used together to ensure that the concept of operation is reasonable. This might include how mission data of interest, such as engineering or scientific data, are captured, returned to Earth, processed, made available to users, and archived for future reference. It is typically developed by the operational team. (See NPR 7120.5.)
100 km
Low Lunar Orbit
Low Earth
OrbitAscen t Stage
 Expended
LunarSurfaceAccess
Module(LSAM) Crew Exploration VehicleEarth Departure Stage Expended
Direct or Skip Land Entry
EarthMoon
LSAM Performs Lunar Orbit I njection
Earth Departure Stage
FIGURE 4.1 -3  Example of a Lunar Sortie DRM Early in the Life Cycle524.0 System Design Processes
Appendix S  contains one possible outline for developing 
a ConOps. The specific sections of the ConOps will 
vary depending on the scope and purpose of the project.
4.1.1.2.5   Define Stakeholder Expectations in 
Acceptable Statements
Once the ConOps has been developed, any gaps or 
ambiguities have been resolved, and understanding between the technical team and stakeholders about 
what is expected/intended for the system/product has 
been achieved, the expectations can be formally doc -
umented. This often comes in the form of NGOs, mission success criteria, and design drivers. These may be captured in a document, spreadsheet, model, or other form appropriate to the product.
The design drivers  will be strongly dependent upon 
the ConOps, including the operational environment, 
orbit, and mission duration requirements. For science missions, the design drivers include, at a minimum, 
the mission launch date, duration, and orbit, as well 
as operational considerations. If alternative orbits are to be considered, a separate concept is needed for each orbit. Exploration missions should consider the destination, duration, operational sequence (and sys-tem configuration changes), crew interactions, main -
tenance and repair activities, required training, and in situ exploration activities that allow the explora -
tion to succeed.
4.1.1.2.6   Analyze Expectations Statements for Measures 
of Effectiveness
The mission success criteria  define what the mission 
needs to accomplish to be successful. This could be 
in the form of science missions, exploration concept 
for human exploration missions, or a technological 
goal for technology demonstration missions. The success criteria also define how well the concept measurements or exploration activities should be accomplished. The success criteria capture the stake -
holder expectations and, along with programmatic requirements and constraints, are used within the high-level requirements.
Measures of Effectiveness (MOEs) are the measures 
of success that are designed to correspond to accom -
plishment of the system objectives as defined by the stakeholder’s expectations. They are stated from the stakeholder’s point of view and represent criteria that 
are to be met in order for the stakeholder to consider 
the project successful. As such, they can be synon -
ymous with mission/project success criteria. MOEs are developed when the NGOs or other stakeholder expectation documentation is developed. Additional 
information on MOEs is contained in Section 6.7.2.4 
of the NASA Expanded Guidance for SE document at 
https://nen.nasa.gov/web/se/doc-repository .
4.1.1.2.7   Validate That Defined Expectation Statements 
Reflect Bidirectional Traceability
The NGOs or other stakeholder expectation doc -
umentation should also capture the source of the 
expectation. Depending on the location within the 
product layer, the expectation may be traced to an 
NGO or a requirement of a higher layer product, to organizational strategic plans, or other sources. Later functions and requirements will be traced to these NGOs. The use of a requirements management tool or model or other application is particularly useful in 
capturing and tracing expectations and requirements.
4.1.1.2.8   Obtain Stakeholder Commitments to the 
Validated Set of Expectations
Once the stakeholder and the technical team are 
in agreement with the expressed stakeholder expec -
tations and the concept of operations, signatures or 
other forms of commitment are obtained. In order to 
obtain these commitments, a concept review is typi -
cally held on a formal or informal basis depending on the scope and complexity of the system (see 
Section 
6.7). The stakeholder expectations (e.g., NGOs), 
MOEs, and concept of operations are presented, discussed, and refined as necessary to achieve final 534.0 System Design Processes
agreement. This agreement shows that both sides 
have committed to the development of this product.
4.1.1.2.9  Baseline Stakeholder Expectations
The set of stakeholder expectations (e.g., NGOs and MOEs) and the concept of operations that are agreed upon are now baselined. Any further changes 
will be required to go through a formal or informal 
(depending on the nature of the product) approval process involving both the stakeholder and the 
technical  team.
4.1.1.2.10  Capture Work Products
In addition to developing, documenting, and base -
lining stakeholder expectations, the ConOps and MOEs discussed above and other work products from 
this process should be captured. These may include 
key decisions made, supporting decision rationale and assumptions, and lessons learned in performing these activities.
4.1.1.3  Outputs
Typical outputs for capturing stakeholder expecta -
tions include the following:
• Validated Stakeholder Expectations: These are 
the agreed-to set of expectations for this product layer. They are typically captured in the form of 
needs, goals, and objectives with constraints and 
assumptions identified. They may also be in the form of models or other graphical forms.
• Concept of Operations:  The ConOps describes 
how the system will be operated during the life cycle phases that will meet stakeholder expecta -
tions. It describes the system characteristics from an operational perspective and helps facilitate an understanding of the system goals and objectives and other stakeholder expectations. Examples would be the ConOps document, model, or a Design Reference Mission (DRM).• Enabling Product Support Strategies: These 
include any special provisions that might be needed for fabrication, test, deployment, opera -
tions sustainment, and disposal of the end prod -
uct. They identify what support will be needed and any enabling products that will need to be developed in order to generate the end product.
• Measures of Effectiveness: A set of MOEs is 
developed based on the stakeholder expectations. These are measures that represent expectations 
that are critical to the success of the system, and 
failure to satisfy these measures will cause the stakeholder to deem the system unacceptable.

Other outputs that might be generated:
• Human/Systems Function Allocation:  This 
describes the interaction of the hardware and software systems with all personnel and their 
supporting infrastructure. In many designs (e.g., 
human space flight) human operators are a critical total-system component and the roles and respon -
sibilities of the humans-in-the-system should be clearly understood. This should include all human/system interactions required for a mission 
including assembly, ground operations, logistics, 
in-flight and ground maintenance, in-flight oper -
ations, etc.
4.1.2   Stakeholder Expectations 
Definition Guidance
Refer to Section 4.1.2 in the NASA Expanded 
Guidance for Systems Engineering at https://nen.
nasa.gov/web/se/doc-repository  for additional guid-
ance on:
• Concept of Operations (including examples),
• protection of space assets, and
• identification of stakeholders for each phase.544.0 System Design Processes
4.2 Technical Requirements 
The Technical Requirements Definition Process 
transforms the stakeholder expectations into a defi -
nition of the problem and then into a complete set 
of validated technical requirements expressed as 
“shall” statements that can be used for defining a design solution for the Product Breakdown Structure (PBS) and related enabling products. The process of requirements definition is a recursive and iterative one that develops the stakeholders’ requirements, prod -
uct requirements, and lower level product/compo -
nent requirements. The requirements should enable the description of all inputs, outputs, and required relationships between inputs and outputs, including constraints, and system interactions with operators, 
maintainers, and other systems. The requirements 
documents organize and communicate requirements to the customer and other stakeholders and the tech -
nical community.
NOTE: 
It is important to note that the team 
must not rely solely on the requirements received to 
design and build the system. Communication and iteration with the relevant stakeholders are essential to ensure a mutual understanding of each require -
ment. Otherwise, the designers run the risk of misunderstanding and implementing an unwanted solution to a different interpretation of the require -
ments. This iterative stakeholder communication is a critically important part of project validation. Always confirm that the right products and results are being developed.
Technical requirements definition activities apply to 
the definition of all technical requirements from the program, project, and system levels down to the low -
est level product/component requirements document.4.2.1  Process Description
FIGURE 4.2-1 provides a typical flow diagram for the 
Technical Requirements Definition Process and iden -
tifies typical inputs, outputs, and activities to con -
sider in addressing technical requirements definition.
4.2.1.1  Inputs
Typical inputs needed for the requirements process include the following:
• Baselined Stakeholder Expectations:  This is the 
agreed-to set of stakeholder expectations (e.g., needs, goals, objectives, assumptions, constraints, 
external interfaces) for the product(s) of this prod -
uct layer.
• Baselined Concept of Operations: This describes 
how the system will be operated during the life 
cycle phases to meet stakeholder expectations. It 
describes the system characteristics from an oper -
ational perspective and helps facilitate an under -
standing of the system goals, objectives, and 
constraints. It includes scenarios, use cases, and/or Design Reference Missions (DRMs) as appropriate for the project. It may be in the form of a docu -
ment, graphics, videos, models, and/or simulations.
• Baselined Enabling Support Strategies: These 
describe the enabling products that were identi -
fied in the Stakeholder Expectations Definition 
Process as needed to develop, test, produce, 
operate, or dispose of the end product. They also include descriptions of how the end product will be supported throughout the life cycle.
• Measures of Effectiveness:  These MOEs were 
identified during the Stakeholder Expectations Definition Process as measures that the stake -
holders deemed necessary to meet in order for the project to be considered a success (i.e., to meet success criteria).554.0 System Design Processes
Other inputs that might be useful in determining the 
technical requirements:
describes the interaction of the hardware and software systems with all personnel and their sup -
porting infrastructure. When human operators are a critical total-system component, the roles and responsibilities of the humans-in-the-system should be clearly understood. This should include all human/system interactions required for a mis -
sion including assembly, ground operations, logis -
tics, in-flight and ground maintenance, in-flight operations, etc.Technical Performance
Measures Baselined Stakeholder 
ExpectationsValidated Technical
Requirements 
Baselined Concept of
Operations 
Measures of
Effectiveness Baselined Enabling
Support Strategies From Stakeholder
Expectations Definition
and  Configuration 
Management P rocesses  
Performance To Logical Decomposition
and Technical Data
Management Processes  
To Technical
Assessment Process To Logical Decomposition
and Requirements
 and  Interface Management
Processes    
Define perfo rmance
requi remen ts for each
defined functional and
behavioral expectation  
performance measures   Define design and
produc t constraints 
Validate technical
requirements 
Establish technical
requirements baseline  Define functional and 
behavioral expectation in
technical terms Analyze scope of problem
Define technical require-
ments in acceptable 
“shall” statements 
Define measures of
Define technicalperformance for each
measure of effectiveness
Capture work products from technical 
requirements definition activities
FIGURE 4.2 -1 Tec hnical Requirements Definition Process
4.2.1.2  Process Activities
4.2.1.2.1   Define Constraints, Functional and 
Behavioral Expectations
The top-level requirements and expectations are ini -
tially assessed to understand the technical problem 
to be solved (scope of the problem) and establish the design boundary. This boundary is typically estab -
lished by performing the following activities:
• Defining constraints that the design needs to adhere to or that limit how the system will be used. The constraints typically cannot be changed based on trade-off analyses.
• Identifying those elements that are already under design control and cannot be changed. This helps 564.0 System Design Processes
establish those areas where further trades will be 
made to narrow potential design solutions.
• Identifying external and enabling systems with which the system should interact and establishing physical and functional interfaces (e.g., mechani -
cal, electrical, thermal, human, etc.).
• Defining functional and behavioral expectations for the range of anticipated uses of the system as identified in the ConOps. The ConOps describes how the system will be operated and the possible use-case scenarios.
4.2.1.2.2  Define Requirements
A complete set of project requirements includes those that are decomposed and allocated down to design elements through the PBS and those that cut across product boundaries. Requirements allocated to the PBS can be functional requirements (what functions need to be performed), performance requirements (how well these functions should be performed), and interface requirements (product to product interaction requirements). Crosscutting require -
ments include environmental, safety, human factors, and those that originate from the “-ilities” and from Design and Construction (D&C) standards. 
FIGURE 
4.2-2 is a general overview on the flow of require -
ments, what they are called, and who is responsible (owns) for approving waivers.
• Functional requirements define what 
functions need to be performed to accomplish the objectives.
• Performance requirements define how well the system needs to perform the functions.
With an overall understanding of the constraints, 
physical/functional interfaces, and functional/behav -
ioral expectations, the requirements can be further defined by establishing performance and other tech -
nical criteria. The expected performance is expressed as a quantitative measure to indicate how well each product function needs to be accomplished.
EXAMPLE OF FUNCTIONAL AND PERFORMANCE REQUIREMENTS
Initial Function Statement
The Thrust Vector Controller (TVC) shall provide vehicle control about the pitch and yaw axes.
This statement describes a high-level function that the TVC must perform. The technical team needs to 
transform this statement into a set of design-to functional and performance requirements.

Functional Requirements with Associated Performance Requirements
• The TVC shall gimbal the engine a maximum of 9 degrees, ± 0.1 degree.
• The TVC shall gimbal the engine at a maximum rate of 5 degrees/second ± 0.3 degrees/second.
• The TVC shall provide a force of 40,000 pounds, ± 500 pounds.
• The TVC shall have a frequency response of 20 Hz, ± 0.1 Hz.574.0 System Design Processes
NOTE: Requirements can be generated from 
non-obvious stakeholders and may not directly 
support the current mission and its objectives, but instead provide an opportunity to gain additional benefits or information that can support the Agency or the Nation. Early in the process, the systems engineer can help identify potential areas where the system can be used to collect unique information that is not directly related to the primary mission. Often outside groups are not aware of the system goals and capabilities until it is almost too late in the process.
Technical requirements come from a number of 
sources including functional, performance, interface, environmental, safety, human interfaces, standards and in support of the “’ilities” such as reliability, sus -
tainability, producibility and others. Consideration and inclusion of all types of requirements is needed in order to form a complete and consistent set of Program	
Project	
RequirementsMission	Directorate
Imposed	Requirements
Program
Imposed	
RequirementsSelf-Imposed	
Derived
Self-Imposed	
Derived
Likewise	flow	to	
Lower	Level	
Systems“Programmatic”	
Technical	
RequirementsOwned	by	
Program/	
Project
Owned	by	
Technical	
AuthorityAll
See	note*Ownership Type Flow
Ex:		At	least	one	major	
element	shall	be	provided	by	the	international	community.
Ex:		The	spacecraft	shall	provide	a	direct	Earth	entry	
capability	for	11500	m/s	or	
greater.Ex:		The	spacecraft	shall	provide	a	direct	Earth	entry	capability	for	11500	m/s	or	greater.
Ex:		The	system	shall	have	a	1.4	factor	of	safety
*	Requirements	 invoked	by	OCE,	OSMA	and	OCHMO	directives,	technical	standards		and	Center	institutional	requirements
FIGURE 4.2-2  Flow , Type and Ownership of Requirements
technical requirements from which the system will 
be architected and designed. FIGURE 4.2-3  shows an 
example of parent and child requirement flowdown.
4.2.1.2.3   Define Requirements in Acceptable 
Statements
Finally, the requirements should be defined in accept -
able “shall” statements, which are complete sentences 
with a single “shall” per statement. Rationale for the requirement should also be captured to ensure the reason and context of the requirement is understood. The Key Driving Requirements (KDRs) should be identified. These are requirements that can have a large impact on cost or schedule when implemented. A KDR can have any priority or criticality. Knowing the impact that a KDR has on the design allows bet -
ter management of requirements.
See 
Appendix C  for guidance and a checklist on how 
to write good requirements and Appendix E  for val -
idating requirements. A well-written requirements 584.0 System Design Processes
document provides several specific benefits to both 
the stakeholders and the technical team as shown in 
TABLE 4.2-1 .System
Performance
RequirementsEnvironmental
and Other Design
and Guidelines Institutional
AssumptionsImplementing
OrganizationsCustomerProgrammatics:
• Cost
• Schedule
• Constraints
• Mission ClassificationMission
Objectives 
System
Functional
Subsystem A
Functional and
RequirementsSubsystem
CMission
Allocated
RequirementsDerived
RequirementsSubsystem X
Allocated
B
...Mission
Authority 
FIGURE 4.2 -3 The  Flowdown of Requirements
I
t is useful to capture information about each of the 
requirements, called metadata, for future reference and use. Many requirements management tools will request or have options for storing this type of infor -
m
ation. TABLE 4.2-2  provides examples of the types of 
metadata that might be useful.
4.2.1.2.4  Validate T echnical Requirements
An important part of requirements definition is the validation of the requirements against the stakeholder 594.0 System Design Processes
TABLE 4.2-1  Benefits of Well-Written Requirements
Benefit Rationale
Establish the basis for 
agreement between the stakeholders and the developers on what the product is to doThe complete description of the functions to be performed by the product specified in the requirements will assist the potential users in determining if the product specified meets their needs or how the product should be modified to meet their needs. During system design, requirements are allocated to subsystems (e.g., hardware, software, and other major components of the system), people, or processes.
Reduce the development 
effort because less rework 
is required to address poorly written, missing, and misunderstood requirementsThe Technical Requirements Definition Process activities force the relevant 
stakeholders to rigorously consider all of the requirements before design begins. 
Careful review of the requirements can reveal omissions, misunderstandings, and inconsistencies early in the development cycle when these problems are easier to correct thereby reducing costly redesign, remanufacture, recoding, and retesting in later life cycle phases.
Provide a basis for estimating costs and schedulesThe description of the product to be developed as given in the requirements is a realistic basis for estimating project costs and can be used to evaluate bids or price estimates.
Provide a baseline for verification and validationOrganizations can develop their verification and validation plans much more productively from a good requirements document. Both system and subsystem test plans and procedures are generated from the requirements. As part of the 
development, the requirements document provides a baseline against which 
compliance can be measured. The requirements are also used to provide the stakeholders with a basis for acceptance of the system.
Facilitate transfer The requirements make it easier to transfer the product. Stakeholders thus find it easier to transfer the product to other parts of their organization, and developers find it easier to transfer it to new stakeholders or reuse it.
Serve as a basis for enhancementThe requirements serve as a basis for later enhancement or alteration of the finished product.
TABLE 4.2 -2  Requirements Metadata
Item Function
Requirement ID Provides a unique numbering system for sorting and tracking.
Rationale Provides additional information to help clarify the intent of the requirements at the time they were written. (See “Rationale” box below on what should be captured.)
Traced from Captures the bidirectional traceability between parent requirements and lower level (derived) requirements and the relationships between requirements.
Owner Person or group responsible for writing, managing, and/or approving changes to this requirement.
Verification method Captures the method of verification (test, inspection, analysis, demonstration) and should be determined as the requirements are developed.
Verification lead Person or group assigned responsibility for verifying the requirement.
Verification level Specifies the level in the hierarchy at which the requirements will be verified (e.g., system, subsystem, element).604.0 System Design Processes
RATIONALE
The rationale should be kept up to date and include the following information:
• Reason for the Requirement: Often the reason for the requirement is not obvious, and it may be lost if 
not recorded as the requirement is being documented. The reason may point to a constraint or concept of operations. If there is a clear parent requirement or trade study that explains the reason, then it should be referenced.
• Document Assumptions:  If a requirement was written assuming the completion of a technology 
development program or a successful technology mission, the assumption should be documented.
• Document Relationships: The relationships with the product’s expected operations (e.g., expectations about how stakeholders will use a product) should be documented. This may be done with a link to the ConOps.
• Document Design Constraints: Constraints imposed by the results from decisions made as the design evolves should be documented. If the requirement states a method of implementation, the rationale should state why the decision was made to limit the solution to this one method of implementation.
expectations, the mission objectives and constraints, 
the concept of operations, and the mission success criteria. Validating requirements can be broken into six steps:
1. Are the Requirements Written Correctly?

1. Are the Requirements Written Correctly? 
Identify and correct requirements “shall” state -
ment format errors and editorial errors.
2. Are the Requirements Technically Correct? A 
few trained reviewers from the technical team identify and remove as many technical errors as possible before having all the relevant stakehold -
ers review the requirements. The reviewers should check that the requirement statements (a) have bidirectional traceability to the baselined stake -
holder expectations; (b) were formed using valid assumptions; and (c) are essential to and consis -
tent with designing and realizing the appropriate product solution form that will satisfy the appli -
cable product life cycle phase success criteria.3. Do the Requirements Satisfy Stakeholders? 
All relevant stakeholder groups identify and remove defects.
4. Are the Requirements Feasible? All require -
ments should make technical sense and be possi -
ble to achieve.
5. Are the Requirements Verifiable? All require -
ments should be stated in a fashion and with enough information that it will be possible to verify the requirement after the end product is implemented.
6. Are the Requirements Redundant or Over-
specified?  All requirements should be unique 
(not redundant to other requirements) and nec -
essary to meet the required functions, perfor -
mance, or behaviors.614.0 System Design Processes
Requirements validation results are often a decid -
ing factor in whether to proceed with the next pro -
cess of Logical Decomposition or Design Solution 
Definition. The project team should be prepared to: 
(1) demonstrate that the project requirements are complete and understandable; (2) demonstrate that evaluation criteria are consistent with requirements and the operations and logistics concepts; (3) con -
firm that requirements and MOEs are consistent 
with stakeholder needs; (4) demonstrate that oper -
ations and architecture concepts support mission 
needs, goals, objectives, assumptions, guidelines, and constraints; and (5) demonstrate that the process for managing change in requirements is established, doc -
umented in the project information repository, and communicated to stakeholders.
4.2.1.2.5  Define MOPs and TPMs
Measures of Performance (MOPs) define the perfor -
mance characteristics that the system should exhibit when fielded and operated in its intended environment. 
MOPs are derived from the MOEs but are stated in 
more technical terms from the supplier’s point of view. Typically, multiple MOPs, which are quantitative and measurable, are needed to satisfy a MOE, which can be qualitative. From a verification and acceptance point of view, MOPs reflect the system characteristics 
deemed necessary to achieve the MOEs.
Technical Performance Measures (TPMs) are phys -
ical or functional characteristics of the system asso -
ciated with or established from the MOPs that are 
deemed critical or key to mission success. The TPMs 
are monitored during implementation by comparing the current actual achievement or best estimate of the parameters with the values that were anticipated for the current time and projected for future dates. They are used to confirm progress and identify deficien -
cies that might jeopardize meeting a critical system requirement or put the project at cost or schedule risk.For additional information on MOPs and TPMs, their relationship to each other and MOEs, and examples of each, see Section 6.7.2.6.2 of the NASA Expanded Guidance for SE document at 
nasa.gov/web/se/doc-repository .
4.2.1.2.6  Establish T echnical Requirement Baseline
Once the technical requirements are identified and validated to be good (clear, correct, complete, and achievable) requirements, and agreement has been 
gained by the customer and key stakeholders, they 
are baselined and placed under configuration control. Typically, a System Requirements Review (SRR) is held to allow comments on any needed changes and to gain agreement on the set of requirements so that it may be subsequently baselined. For additional infor -
mation on the SRR, see 
Section 6.7 .
4.2.1.2.7  Capture Work Products
The work products generated during the above activ -
ities should be captured along with key decisions that were made, any supporting decision rationale 
and assumptions, and lessons learned in performing 
these activities.
4.2.1.3  Outputs
• Validated Technical Requirements:  This is the 
approved set of requirements that represents a complete description of the problem to be solved 
and requirements that have been validated and 
approved by the customer and stakeholders. Examples of documents that capture the require -
ments are a System Requirements Document (SRD), Project Requirements Document (PRD), Interface Requirements Document (IRD), and a 
Software Requirements Specification (SRS).
• Measures of Performance: These are the iden -
tified quantitative measures that, when met 
by the design solution, help ensure that one 
or more MOEs will be satisfied. There may be 624.0 System Design Processes
two or more MOPs for each MOE. See Section 
6.7.2.6.2in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/
se/doc-repository  for further details.
• Technical Performance Measures:  These are the 
set of performance measures that are monitored and trended by comparing the current actual 
achievement of the parameters with that expected 
or required at the time. TPMs are used to confirm progress and identify deficiencies. See Section 6.7.2.6.2 in the NASA Expanded Guidance for Systems Engineering at 
4.2.2   Technical Requirements 
Refer to Section 4.2.2 of the NASA Expanded 
Guidance for SE document at https://nen.nasa.gov/
web/se/doc-repository  for additional information on:
• types of requirements,
• requirements databases, and
• the use of technical standards.
4.3 Logical Decomposition
Logical decomposition is the process for creating the detailed functional requirements that enable NASA programs and projects to meet the stakeholder expec -
tations. This process identifies the “what” that should be achieved by the system at each level to enable a successful project. Logical decomposition utilizes functional analysis to create a system architecture and to decompose top-level (or parent) requirements and allocate them down to the lowest desired levels 
of the project.
The Logical Decomposition Process is used to:
• Improve understanding of the defined techni-
cal requirements and the relationships among the requirements (e.g., functional, performance, behavioral, and temporal etc.), and
• Decompose the parent requirements into a set of logical decomposition models and their associated sets of derived technical requirements for input to 
the Design Solution Definition Process.
4.3.1  Process Description
FIGURE 4.3-1  provides a typical flow diagram for the 
Logical Decomposition Process and identifies typical 
inputs, outputs, and activities to consider in address -
ing logical decomposition.
4.3.1.1  Inputs
Typical inputs needed for the Logical Decomposition Process include the following:
• Technical Requirements: A validated set of 
requirements that represent a description of the problem to be solved, have been established by 
functional and performance analysis, and have 
been approved by the customer and other stake -
holders. Examples of documents that capture the requirements are an SRD, PRD, and IRD.
• Technical Measures:  An established set of mea -
sures based on the expectations and requirements that will be tracked and assessed to determine 
overall system or product effectiveness and cus -
tomer satisfaction. These measures are MOEs, 
MOPs, and a special subset of these called TPMs. See Section 6.7.2.6.2 in the NASA Expanded Guidance for Systems Engineering at 
nasa.gov/web/se/doc-repository  for further details.
4.3.1.2  Process Activities
4.3.1.2.1   Define One or More Logical Decomposition 
Models
The key first step in the Logical Decomposition 
Process is establishing the system architecture model. The system architecture activity defines the 634.0 System Design Processes
underlying structure and relationships of hardware, 
software, humans-in-the-loop, support personnel, communications, operations, etc., that provide for the implementation of Agency, mission director -
ate, program, project, and subsequent levels of the requirements. System architecture activities drive the partitioning of system elements and requirements to lower level functions and requirements to the point that design work can be accomplished. Interfaces and relationships between partitioned subsystems and elements are defined as well.From Technical
 
and Configuration
ManagemenRequirements Definition
Requirements Definitiont Processes  
To Technical Data
Management ProcessDeri ved Technical 
Logical Decomposition
Work ProductsBaselined Technical 

Measures of 
Performance 
To Design Solution and 
ModelsFrom Technical
Management Processes To Design Solution
and  Configuration
Management Processes   Define one or more logical
decomposition models 
Allocate technical requirements to
logical decomposition models to form
a set of derived technical requirements  
Resolve derived technical 
requirements conflicts  
Validate the resulting set of derived
technical requirements  
Establish the derived technical
requirements baseline
Capture work products from logical
decomposition activities 
FIGURE 4.3 -1 Log ical Decomposition Process
O
nce the top-level (or parent) functional require -
ments and constraints have been established, the 
system designer uses functional analysis to begin to formulate a conceptual system architecture. The system architecture can be seen as the strategic orga -
nization of the functional elements of the system, laid out to enable the roles, relationships, dependen -
cies, and interfaces between elements to be clearly defined and understood. It is strategic in its focus o
n the overarching structure of the system and how 
its elements fit together to contribute to the whole, instead of on the particular workings of the elements themselves. It enables the elements to be developed separately from each other while ensuring that they work together effectively to achieve the top-level (or parent) requirements.
Much like the other elements of functional decom -
position, the development of a good system-level 
architecture is a creative, recursive, collaborative, and iterative process that combines an excellent under -
standing of the project’s end objectives and constraints with an equally good knowledge of various potential 
technical means of delivering the end  products.
Focusing on the project’s ends, top-level (or parent) requirements, and constraints, the system architect should develop at least one, but preferably multiple, 644.0 System Design Processes
concept architectures capable of achieving program 
objectives. Each architecture concept involves spec -
ification of the functional elements (what the pieces 
do), their relationships to each other (interface defi -
nition), and the ConOps, i.e., how the various seg -
ments, subsystems, elements, personnel, units, etc., 
will operate as a system when distributed by location and environment from the start of operations to the end of the mission.
The development process for the architectural con -
cepts should be recursive and iterative with feedback 
from stakeholders and external reviewers, as well as from subsystem designers and operators, provided as 
often as possible to increase the likelihood of effec -
tively achieving the program’s desired ends while 
reducing the likelihood of cost and schedule overruns.
In the early stages of development, multiple con -
cepts are generated. Cost and schedule constraints 
will ultimately limit how long a program or project 
can maintain multiple architectural concepts. For all NASA programs, architecture design is completed during the Formulation Phase. For most NASA proj -
ects (and tightly coupled programs), the baselining 
of a single architecture happens during Phase A. 
Architectural changes at higher levels occasionally occur as decomposition to lower levels produces com -
plexity in design, cost, or schedule that necessitates such changes. However, as noted in 
FIGURE 2.5-1 , the 
later in the development process that changes occur, the more expensive they become.
Aside from the creative minds of the architects, there 
are multiple tools that can be utilized to develop a system’s architecture. These are primarily modeling and simulation tools, functional analysis tools, archi -
tecture frameworks, and trade studies. (For example, 
one way of doing architecture is the Department of 
Defense (DOD) Architecture Framework (DODAF). A search concept is developed, and analytical models of the architecture, its elements, and their operations are developed with increased fidelity as the project evolves. Functional decomposition, requirements development, and trade studies are subsequently undertaken. Multiple iterations of these activities feed back to the evolving architectural concept as the 
requirements flow down and the design matures.
4.3.1.2.2   Allocate T echnical Requirements, Resolve 
Conflicts, and Baseline
Functional analysis is the primary method used in 
system architecture development and functional requirement decomposition. It is the systematic pro -
cess of identifying, describing, and relating the func -
tions a system should perform to fulfill its goals and objectives. Functional analysis identifies and links system functions, trade studies, interface character -
istics, and rationales to requirements. It is usually based on the ConOps for the system of interest.
Three key steps in performing functional analysis are:
1. Translate top-level requirements into functions 
that should be performed to accomplish the requirements.
2. Decompose and allocate the functions to lower levels of the product breakdown structure.
3. Identify and describe functional and subsystem interfaces.
The process involves analyzing each system require -
ment to identify all of the functions that need to be performed to meet the requirement. Each function identified is described in terms of inputs, outputs, failure modes, consequence of failure, and inter -
face requirements. The process is repeated from 
the top down so that sub-functions are recognized 
as part of larger functional areas. Functions are arranged in a logical sequence so that any specified operational usage of the system can be traced in an 
end-to-end  path.654.0 System Design Processes
The process is recursive and iterative and continues 
until all desired levels of the architecture/system have been analyzed, defined, and baselined. There will 
almost certainly be alternative ways to decompose 
functions. For example, there may be several ways to communicate with the crew: Radio Frequency (RF), laser, Internet, etc. Therefore, the outcome is highly dependent on the creativity, skills, and experience of the engineers doing the analysis. As the analysis 
proceeds to lower levels of the architecture and sys -
tem, and the system is better understood, the systems 
engineer should keep an open mind and a willingness to go back and change previously established archi -
tecture and system requirements. These changes will 
then have to be decomposed down through the archi -
tecture and sub-functions again with the recursive 
process continuing until the system is fully defined with all of the requirements understood and known to be viable, verifiable, and internally consistent. Only at that point should the system architecture and 
requirements be baselined.
4.3.1.2.3  Capture Work Products
The other work products generated during the 
Logical Decomposition Process should be captured along with key decisions made, supporting decision 
rationale and assumptions, and lessons learned in 
performing the activities.
4.3.1.3  Outputs
Typical outputs of the Logical Decomposition Process include the following:
• Logical Decomposition Models:  These models 
define the relationship of the requirements and functions and their behaviors. They include the 
system architecture models that define the under -
lying structure and relationship of the elements 
of the system (e.g., hardware, software, humans-in-the-loop, support personnel, communications, operations, etc.) and the basis for the partitioning of requirements into lower levels to the point that design work can be accomplished.
• Derived Technical Requirements:  These are 
requirements that arise from the definitions of the selected architecture that were not explicitly 
stated in the baselined requirements that served as 
an input to this process. Both the baselined and derived requirements are allocated to the system architecture and functions.
• Logical Decomposition Work Products: These 
are the other products generated by the activities of this process.
4.3.2   Logical Decomposition 
Guidance
Refer to Section 4.3.2 and Appendix F in the NASA 
Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-repository  for addi -
tional guidance on:
• Product Breakdown Structures and
• Functional Analysis Techniques.
4.4 Design Solution Definition
The Design Solution Definition Process is used to translate the high-level requirements derived from the stakeholder expectations and the outputs of the 
Logical Decomposition Process into a design solu -
tion. This involves transforming the defined logical 
decomposition models and their associated sets of derived technical requirements into alternative solu -
tions. These alternative solutions are then analyzed through detailed trade studies that result in the

Guidance
tions. These alternative solutions are then analyzed through detailed trade studies that result in the 
selection of a preferred alternative. This preferred 
alternative is then fully defined into a final design solution that satisfies the technical requirements. This design solution definition is used to generate the end product specifications that are used to produce 664.0 System Design Processes
the product and to conduct product verification. This 
process may be further refined depending on whether there are additional subsystems of the end product that need to be defined.
4.4.1  Process Description
FIGURE 4.4-1  provides a typical flow diagram for the 
Design Solution Definition Process and identifies typical inputs, outputs, and activities to consider in addressing design solution definition.
4.4.1.1 Inputs
There are several fundamental inputs needed to initi -
ate the Design Solution Definition Process:
 * To Implementation ProcessBaselined Logical
Models System-Speci d
Requirements To Requirements  and
Interface Management Processes 
Initial Su
 SpecificationsbsystemTo Stakeholder Expectations Definition
and Requirements  and Interface
Product Validation
Plan To Product Va lida tion Process
Logistics and Operate-
To ProceduresTo Technical Data Management ProcessEnabling Product
RequirementsTo Stakeholder Expectations Definition
or Product Implementation and
Management Processes   From Logical 
Decomposition  and
Configuration Management
Processes
Initiate development
of enabling products No Yes
Initiate development 
of next lower level
products Define alternative design solutions
Analyze ea ch alternative design solution
Select best d esign solution alternative
Generate full design description of the
selected solution
Verify
Capture work products from design solution 
definition activities the fully defin ed design solution
Baseline design solution specified requirements
and  design descriptions  
No
*Need
lower level
product?  Yes
*Enabling
product
exists? End Product–Specified
Product Verification
Plan To Product Verification ProcessBaselined Derived
Technical
FIGURE 4.4 -1 De sign Solution Definition Process• Technical Requirements:  These are the customer 
and stakeholder needs that have been translated into a complete set of validated requirements for the system, including all interface requirements.
• Logical Decomposition Models: Requirements 
are analyzed and decomposed by one or more different methods (e.g., function, time, behavior, data flow, states, modes, system architecture, etc.) in order to gain a more comprehensive under -
standing of their interaction and behaviors. (See the definition of a model in 
Appendix B .)674.0 System Design Processes
4.4.1.2 Process Activities
4.4.1.2.1 Define Alternative Design Solutions
The realization of a system over its life cycle involves 
a succession of decisions among alternative courses of action. If the alternatives are precisely defined and thoroughly understood to be well differentiated in the cost-effectiveness space, then the systems engi -
neer can make choices among them with confidence.
To obtain assessments that are crisp enough to facili -
tate good decisions, it is often necessary to delve more 
deeply into the space of possible designs than has yet been done, as illustrated in 
FIGURE 4.4-2 . It should 
be realized, however, that this illustration represents neither the project life cycle, which encompasses the system development process from inception through disposal, nor the product development pro -
cess by which the system design is developed and implemented.Recognize 
need/
opportunityIdentify and 
quantify goals
Create conceptsIdentify and 
Identify and 
Create concepts
Do trade studies
Do trade studiesSelect
design
Select
design
Select
designSelect
designDo trade studiesIncreaseresolution
Perform
mission                Implement decisionsIncreaseresolutionIncreaseresolution
FIGURE 4.4 -2 The D octrine of Successive Refinement
E
ach “create concepts” step in FIGURE 4.4-2  involves a 
recursive and iterative design loop driven by the set of stakeholder expectations where a straw man architec -
ture/design, the associated ConOps, and the derived requirements are developed and programmatic con -
straints such as cost and schedule are considered. These three products should be consistent with each other and will require iterations and design decisions to achieve this consistency. This recursive and itera -
tive design loop is illustrated in
 FIGURE 4.0-1 .
Each “create concepts” step in FIGURE 4.4-2  also 
involves an assessment of potential capabilities offered by the continually changing state of technology and potential pitfalls captured through experience-based review of prior program/project lessons learned data. It is imperative that there be a continual interaction between the technology development process, cross -
cutting processes such as human systems integration, and the design process to ensure that the design reflects the realities of the available technology and that overreliance on immature technology is avoided. Additionally, the state of any technology that is con -
s
idered enabling should be properly monitored, and 
care should be taken when assessing the impact of this technology on the concept performance. This interaction is facilitated through a periodic assess-ment of the design with respect to the maturity of the technology required to implement the design. (See Section 4.4.2.1 in the NASA Expanded Guidance for Systems Engineering at 
se/doc-repository  for a more detailed discussion of 
technology assessment.) These technology elements usually exist at a lower level in the PBS. Although the process of design concept development by the integration of lower level elements is a part of the systems engineering process, there is always a danger that the top-down process cannot keep up with the bottom-up process. Therefore, system architecture issues need to be resolved early so that the system can be modeled with sufficient realism to do reliable 
trade  studies.
As the system is realized, its particulars become clearer—but also harder to change. See the rising 684.0 System Design Processes
“Cost to Change Design Direction” in FIGURE 2.5 -1. 
The purpose of systems engineering is to make sure 
that the Design Solution Definition Process happens 
in a way that leads to the most functional, safe, and 
cost-effective final system while working within any given schedule boundaries. The basic idea is that before those decisions that are hard to undo are made, the alternatives should be carefully and itera -
tively assessed, particularly with respect both to the 
maturity of the required technology and to stake -
holder expectations for efficient, effective operations.
4.4.1.2.2  Create Alternative Design Concepts
Once it is understood what the system is to accom -
plish, it is possible to devise a variety of ways that 
those goals can be met. Sometimes, that comes about 
as a consequence of considering alternative func -
tional allocations and integrating available subsystem 
design options, all of which can have technologies at varying degrees of maturity. Ideally, as wide a range of plausible alternatives as is consistent with the design organization’s charter should be defined, keeping in 
mind the current stage in the process of successive 
refinement. When the bottom-up process is operat -
ing, a problem for the systems engineer is that the designers tend to become fond of the designs they create, so they lose their objectivity; the systems engi -
neer should stay an “outsider” so that there is more objectivity. This is particularly true in the assessment of the technological maturity of the subsystems and components required for implementation. There is a tendency on the part of technology developers and project management to overestimate the maturity 
and applicability of a technology that is required to 
implement a design. This is especially true of “heri -
tage” equipment. The result is that critical aspects of systems engineering are often overlooked.
The creation of alternative design solutions involves 
assessment of potential capabilities offered by the continually changing state of technology. A continual interaction between the technology development process and the design process ensures that the design reflects the realities of the available technology. This interaction is facilitated through periodic assessment of the design with respect to the maturity of the tech -
nology required to implement the design.
After identifying the technology gaps existing in 
a given design concept, it is frequently necessary to undertake technology development in order to ascertain viability. Given that resources will always 
be limited, it is necessary to pursue only the most

be limited, it is necessary to pursue only the most 
promising technologies that are required to enable a given concept.
If requirements are defined without fully under -
standing the resources required to accomplish needed 
technology developments, then the program/project is at risk. Technology assessment should be done iter -
atively until requirements and available resources are aligned within an acceptable risk posture. Technology development plays a far greater role in the life cycle 
of a program/project than has been traditionally con -
sidered, and it is the role of the systems engineer to 
develop an understanding of the extent of program/project impacts—maximizing benefits and minimiz -
ing adverse effects. Traditionally, from a program/
project perspective, technology development has 
been associated with the development and incorpo -
ration of any “new” technology necessary to meet requirements. However, a frequently overlooked area is that associated with the modification of “heritage” systems incorporated into different architectures and 
operating in different environments from the ones for 
which they were designed. If the required modifica -
tions and/or operating environments fall outside the realm of experience, then these too should be consid -
ered technology development.
To understand whether or not technology develop -
ment is required—and to subsequently quantify the 694.0 System Design Processes
associated cost, schedule, and risk—it is necessary 
to systematically assess the maturity of each system, subsystem, or component in terms of the architecture 
and operational environment. It is then necessary to 
assess what is required in the way of development to advance the maturity to a point where it can success -
fully be incorporated within cost, schedule, and per -
formance constraints. A process for accomplishing this assessment is described in 
Appendix G . Because 
technology development has the potential for such significant impacts on a program/project, technology 
assessment needs to play a role throughout the design 
and development process from concept development through Preliminary Design Review (PDR). Lessons learned from a technology development point of view should then be captured in the final phase of 
the program.
On the first turn of the successive refinement in 
FIGURE 4.4-2 , the subject is often general approaches 
or strategies, sometimes architectural concepts. On the next, it is likely to be functional design, then 
detailed design, and so on. The reason for avoiding 
a premature focus on a single design is to permit dis -
covery of the truly best design. Part of the systems engineer’s job is to ensure that the design concepts to be compared take into account all interface require -
ments. Characteristic questions include: “Did you 
include the cabling?” or “Did you consider how the 
maintainers can repair the system?” When possible, each design concept should be described in terms of controllable design parameters so that each rep -
resents as wide a class of designs as is reasonable. In 
doing so, the systems engineer should keep in mind 
that the potentials for change may include organi -
zational structure, personnel constraints, schedules, procedures, and any of the other things that make up a system. When possible, constraints should also be described by parameters.4.4.1.2.3  Analyze Each Alternative Design Solution
The technical team analyzes how well each of the design alternatives meets the system objectives (tech -
nology gaps, effectiveness, technical achievability, 
performance, cost, schedule, and risk, both quanti -
fied and otherwise). This assessment is accomplished 
through the use of trade studies. The purpose of the trade study process is to ensure that the system archi -
tecture, intended operations (i.e., the ConOps) and design decisions move toward the best solution that 
can be achieved with the available resources. The 
basic steps in that process are:
• Devise some alternative means to meet the func -
tional requirements. In the early phases of the project life cycle, this means focusing on system 
architectures; in later phases, emphasis is given to 
system designs.
• Evaluate these alternatives in terms of the MOPs and system life cycle cost. Mathematical models are useful in this step not only for forcing rec -
ognition of the relationships among the outcome variables, but also for helping to determine what the MOPs should be quantitatively.
• Rank the alternatives according to appropriate selection criteria.
• Drop less promising alternatives and proceed to the next level of resolution, if needed.
The trade study process should be done openly and inclusively. While quantitative techniques and rules are used, subjectivity also plays a significant role. To make the process work effectively, participants should have open minds, and individuals with dif -
ferent skills—systems engineers, design engineers, 
crosscutting specialty discipline and domain engi -
neers, program analysts, system end users, deci -
sion scientists, maintainers, operators, and project 704.0 System Design Processes
managers—should cooperate. The right quantita -
tive methods and selection criteria should be used. 
Trade study assumptions, models, and results should 
be documented as part of the project archives. The 
participants should remain focused on the functional requirements, including those for enabling products. For an in-depth discussion of the trade study process, see 
Section 6.8 . The ability to perform these studies is 
enhanced by the development of system models that relate the design parameters to those assessments, but 
it does not depend upon them.
The technical team should consider a broad range 
of concepts when developing the system model. The model should define the roles of crew, operators, maintainers, logistics, hardware, and software in 
the system. It should identify the critical technolo -
gies required to implement the mission and should 
consider the entire life cycle from fabrication to disposal. Evaluation criteria for selecting concepts should be established. Cost is always a limiting fac -
tor. However, other criteria, such as time to develop and certify a unit, risk, and reliability, also are crit -
ical. This stage cannot be accomplished without addressing the roles of operators and maintainers. These contribute significantly to life cycle costs and to the system reliability. Reliability analysis should be 
performed based upon estimates of component fail -
ure rates for hardware and an understanding of the 
consequences of these failures. If probabilistic risk assessment models are applied, it may be necessary to include occurrence rates or probabilities for software 
faults or human error events. These models should 
include hazard analyses and controls implemented through fault management. Assessments of the matu -
rity of the required technology should be done and a technology development plan developed.
Controlled modification and development of design 
concepts, together with such system models, often permits the use of formal optimization techniques to find regions of the design space that warrant fur -
ther investigation.
Whether system models are used or not, the design 
concepts are developed, modified, reassessed, and 
compared against competing alternatives in a closed-
loop process that seeks the best choices for further development. System and subsystem sizes are often determined during the trade studies. The end result is the determination of bounds on the relative cost-ef -
fectiveness of the design alternatives, measured in terms of the quantified system goals. (Only bounds, rather than final values, are possible because deter -
mination of the final details of the design is inten -
tionally deferred.) Increasing detail associated with the continually improving resolution reduces the 
spread between upper and lower bounds as the pro -
cess proceeds.
4.4.1.2.4  Select the Best Design Solution Alternative
The technical team selects the best design solution 
from among the alternative design concepts, taking into account subjective factors that the team was 
unable to quantify, such as robustness, as well as 
estimates of how well the alternatives meet the quan -
titative requirements; the maturity of the available technology; and any effectiveness, cost, schedule, risk, or other constraints.
The Decision Analysis Process, as described in 
Section 6.8 , should be used to make an evaluation of 
the alternative design concepts and to recommend 
the “best” design solution.
When it is possible, it is usually well worth the trou -
ble to develop a mathematical expression, called an 
“objective function,” that expresses the values of com -
binations of possible outcomes as a single measure of cost-effectiveness, as illustrated in 
FIGURE 4.4-3 , even 
if both cost and effectiveness should be described by more than one measure.714.0 System Design Processes

BCA
Life-Cycle Cost, Expressed in Constant DollarsSome Aspect of Effectiveness,
Expressed in Quantitative Units
FIGURE 4.4 -3  A Quantitative Objective Function, Dependent 
on Life Cycle Cost and All Aspects of Effectiveness
Note: The different shaded areas indicate different levels 
of uncertainty  .  Dashed lines represent constant values of 
objective function (cost-effectiveness)  . H igher values of cost-
effectiveness are achieved by moving toward upper left  .  A, 
B, and C are design concepts with different risk patterns  .
The objective function (or “cost function”) assigns a 
real number to candidate solutions or “feasible solu -
tions” in the alternative space or “search space.” A 
feasible solution that minimizes (or maximizes, if 
that is the goal) the objective function is called an “optimal solution.” When achievement of the goals can be quantitatively expressed by such an objec -
tive function, designs can be compared in terms of their value. Risks associated with design concepts 
can cause these evaluations to be somewhat nebulous 
because they are uncertain and are best described by probability distributions.
In 
FIGURE 4.4-3 , the risks are relatively high for 
design concept A. There is little risk in either effec -
tiveness or cost for concept B, while the risk of an 
expensive failure is high for concept C, as is shown 
by the cloud of probability near the x axis with a high 
cost and essentially no effectiveness. Schedule factors may affect the effectiveness and cost values and the risk distributions.
The mission success criteria for systems differ sig -
nificantly. In some cases, effectiveness goals may be 
much more important than all others. Other projects may demand low costs, have an immutable sched -
ule, or require minimization of some kinds of risks. Rarely (if ever) is it possible to produce a combined quantitative measure that relates all of the important 
factors, even if it is expressed as a vector with sev -
eral components. Even when that can be done, it is 
essential that the underlying actors and relationships be thoroughly revealed to and understood by the sys -
tems engineer. The systems engineer should weigh 
the importance of the unquantifiable factors along 
with the quantitative  data.
Technical reviews of the data and analyses, includ -
ing technology maturity assessments, are an import -
ant part of the decision support packages prepared for the technical team. The decisions that are made 
are generally entered into the configuration manage -
ment system as changes to (or elaborations of) the system baseline. The supporting trade studies are archived for future use. An essential feature of the systems engineering process is that trade studies are 
performed before decisions are made. They can then 
be baselined with much more confidence.
4.4.1.2.5  Increase the Resolution of the Design
The successive refinement process of FIGURE 4.4-2 
illustrates a continuing refinement of the system design. At each level of decomposition, the baselined derived (and allocated) requirements become the set 
of high-level requirements for the decomposed ele -
ments, and the process begins again. One might ask, 
“When do we stop refining the design?” The answer is that the design effort proceeds to a depth that is sufficient to meet several needs: the design should penetrate sufficiently to allow analytical validation 724.0 System Design Processes
of the design to the requirements and ConOps; 
it should also have sufficient depth to support cost and operations modeling and to convince a review 
team of a feasible design with performance, cost, and 
risk margins.
The systems engineering engine is applied again and 
again as the system is developed. As the system is real -
ized, the issues addressed evolve and the particulars 
of the activity change. Most of the major system deci -
sions (goals, architecture, acceptable life cycle cost, 
etc.) are made during the early phases of the project, so the successive refinements do not correspond pre -
cisely to the phases of the system life cycle. Much of the system architecture can be seen even at the out -
set, so the successive refinements do not correspond exactly to development of the architectural hierarchy either. Rather, they correspond to the successively greater resolution by which the system is defined.
It is reasonable to expect the system to be defined 
with better resolution as time passes. This tendency is formalized at some point (in Phase B) by defin -
ing a baseline system definition. Usually, the goals, objectives, and constraints are baselined as the requirements portion of the baseline. The entire base -
line is then placed under configuration control in an attempt to ensure that any subsequent changes are indeed justified and affordable.
At this point in the systems engineering process, there 
is a logical branch point. For those issues for which 
the process of successive refinement has proceeded far enough, the next step is to implement the decisions at that level of resolution. For those issues that are still insufficiently resolved, the next step is to refine the development further.
4.4.1.2.6  Fully Describe the Design Solution
Once the preferred design alternative has been selected and the proper level of refinement has been completed, then the design is fully defined into a final design solution that will satisfy the technical requirements and ConOps. The design solution defi -
nition will be used to generate the end product speci -
fications that will be used to produce the product and to conduct product verification. This process may be further refined depending on whether there are addi -
tional subsystems of the end product that need to 
be defined.
The scope and content of the full design description should be appropriate for the product life cycle phase, the phase success criteria, and the product position in 
the PBS (system structure). Depending on these fac -
tors, the form of the design solution definition could 
be simply a simulation model or a paper study report. The technical data package evolves from phase to phase, starting with conceptual sketches or models and ending with complete drawings, parts list, and 
other details needed for product implementation or 
product integration. Typical output definitions from the Design Solution Definition Process are shown in 
FIGURE 4.4-1  and are described in Section 4.4.1.3 .
4.4.1.2.7 Verify the Design Solution
Once an acceptable design solution has been selected from among the various alternative designs and doc -
umented in a technical data package, the design 
solution should next be verified against the system 
requirements and constraints. A method to achieve this verification is by means of a peer review to evaluate the resulting design solution definition. Guidelines for conducting a peer review are discussed in Section 6.7.2.4.5.
In addition, peer reviews play a significant role as a 
detailed technical component of higher level tech -
nical and programmatic reviews. For example, the peer review of a component battery design can go 
into much more technical detail on the battery than 
the integrated power subsystem review. Peer reviews 734.0 System Design Processes
can cover the components of a subsystem down to 
the level appropriate for verifying the design against the requirements. Concerns raised at the peer 
review might have implications on the power sub -
system design and verification and therefore should 
be reported at the next higher level review of the power subsystem.
The verification should show that the design solution 
definition:
• Is realizable within the constraints imposed on 
the technical effort;
• Has specified requirements that are stated in acceptable statements and have bidirectional traceability with the technical requirements and 
stakeholder expectations; and
• Has decisions and assumptions made in forming 
the solution consistent with its set of technical requirements and identified system product and 
service constraints.
This design solution verification is in contrast 
to the verification of the end product described in the end product verification plan which is part of the technical data package. That verifi -
cation occurs in a later life cycle phase and is a result of the Product Verification Process (see  
Section 5.3 ) applied to the realization of the design 
solution as an end product.
4.4.1.2.8  Validate the Design Solution
The validation of the design solution is a recursive and iterative process as shown in 
FIGURE 4.0-1 . 
Each alternative design concept is validated against the set of stakeholder expectations. The stakeholder 
expectations drive the iterative design loop in which

expectations drive the iterative design loop in which 
a straw man architecture/design, the ConOps, and the derived requirements are developed. These three products should be consistent with each other and will require iterations and design decisions to achieve this consistency. Once consistency is achieved, func -
tional analyses allow the study team to validate the design against the stakeholder expectations. A sim -
plified validation asks the questions: Does the system work as expected? How does the system respond to failures, faults, and anomalies? Is the system afford -
able? If the answer to any of these questions is no, then changes to the design or stakeholder expecta -
tions will be required, and the process is started over 
again. This process continues until the system—
architecture, ConOps, and requirements—meets the stakeholder expectations.
This design solution validation is in contrast to 
the validation of the end product described in the 
end-product validation plan, which is part of the technical data package. That validation occurs in a later life cycle phase and is a result of the Product Validation Process (see 
Section 5.4 ) applied to the 
realization of the design solution as an end product.
4.4.1.2.9  Identify Enabling Products
Enabling products are the life cycle support prod -
ucts and services (e.g., production, test, deployment, training, maintenance, and disposal) that facili -
tate the progression and use of the operational end product through its life cycle. Since the end prod -
uct and its enabling products are interdependent, they are viewed as a system. Project responsibility thus extends to responsibility for acquiring services from the relevant enabling products in each life cycle 
phase. When a suitable enabling product does not 
already exist, the project that is responsible for the end product can also be responsible for creating and using the enabling product.
Therefore, an important activity in the Design 
Solution Definition Process is the identification of the enabling products and personnel that will be required 744.0 System Design Processes
during the life cycle of the selected design solution 
and then initiating the acquisition or development of those enabling products and personnel. Need dates 
for the enabling products should be realistically 
identified on the project schedules, incorporating appropriate schedule slack. Then firm commitments in the form of contracts, agreements, and/or opera -
tional plans should be put in place to ensure that the enabling products will be available when needed to 
support the product life cycle phase activities. The 
enabling product requirements are documented as part of the technical data package for the Design Solution Definition Process.
An environmental test chamber is an example of an 
enabling product whose use would be acquired at an appropriate time during the test phase of a space flight system.
Special test fixtures or special mechanical handling 
devices are examples of enabling products that would 
have to be created by the project. Because of long development times as well as oversubscribed facil -
ities, it is important to identify enabling products and secure the commitments for them as early in the 
design phase as possible.
4.4.1.2.10  Baseline the Design Solution
As shown earlier in FIGURE 4.0-1 , once the selected 
system design solution meets the stakeholder expec -
tations, the study team baselines the products and prepares for the next life cycle phase. Because of the 
recursive nature of successive refinement, intermedi -
ate levels of decomposition are often validated and baselined as part of the process. In the next level of decomposition, the baselined requirements become the set of high-level requirements for the decomposed 
elements, and the process begins again.
Baselining a particular design solution enables the 
technical team to focus on one design out of all the alternative design concepts. This is a critical point in the design process. It puts a stake in the ground and gets everyone on the design team focused on the same concept. When dealing with complex sys-
tems, it is difficult for team members to design their 
portion of the system if the system design is a mov -
ing target. The baselined design is documented and placed under configuration control. This includes the system requirements, specifications, and configura -
tion descriptions.
While baselining a design is beneficial to the design 
process, there is a danger if it is exercised too early in the Design Solution Definition Process. The early exploration of alternative designs should be free and 
open to a wide range of ideas, concepts, and imple -
mentations. Baselining too early takes the inventive 
nature out of the concept exploration. Therefore, baselining should be one of the last steps in the Design Solution Definition Process.
4.4.1.3  Outputs
Outputs of the Design Solution Definition Process are the specifications and plans that are passed on to the product realization processes. They contain the 
design-to, build-to, train-to, and code-to documen -
tation that complies with the approved baseline for 
the system.
As mentioned earlier, the scope and content of the 
full design description should be appropriate for the 
product life cycle phase, the phase success criteria, 
and the product position in the PBS.
Outputs of the Design Solution Definition Process 
include the following:
• The System Specification: The system spec -
ification contains the functional baseline for the system that is the result of the Design 
Solution Definition Process. The system design 754.0 System Design Processes
specification provides sufficient guidance, con -
straints, and system requirements for the design 
engineers to begin developing the design.
• The System External Interface Specifications: 
The system external interface specifications describe the functional baseline for the behavior and characteristics of all physical interfaces that the 
system has with the external world. These include 
all structural, thermal, electrical, and signal inter -
faces, as well as the human-system interfaces.
• The End-Product Specifications: The end-prod -
uct specifications contain the detailed build-to and code-to requirements for the end product. 
They are detailed, exact statements of design par -
ticulars, such as statements prescribing materials, 
dimensions, and quality of work to build, install, or manufacture the end product.
• The End-Product Interface Specifications: The 
end-product interface specifications contain the detailed build-to and code-to requirements for 
the behavior and characteristics of all logical and 
physical interfaces that the end product has with external elements, including the human-system interfaces.
• Initial Subsystem Specifications:  The end-prod -
uct subsystem initial specifications provide detailed information on subsystems if they are required.
• Enabling Product Requirements:  The require -
ments for associated supporting enabling products provide details of all enabling products. Enabling 
products are the life cycle support products, infra -
structures, personnel, logistics, and services that 
facilitate the progression and use of the opera -
tional end product through its life cycle. They are viewed as part of the system since the end product and its enabling products are interdependent.
• Product Verification Plan:  The end-product ver -
ification plan (generated through the Technical Planning Process) provides the content and 
depth of detail necessary to provide full visibil -
ity of all verification activities for the end prod -
uct. Depending on the scope of the end product, 
the plan encompasses qualification, acceptance, prelaunch, operational, and disposal verification activities for flight hardware and software.
• Product Validation Plan: The end-product val -
idation plan (generated through the Technical Planning Process) provides the content and depth 
of detail necessary to provide full visibility of 
all activities to validate the end product against the baselined stakeholder expectations. The plan identifies the type of validation, the validation procedures, and the validation environment that are appropriate to confirm that the realized end 
product conforms to stakeholder expectations.
• Logistics and Operate-to Procedures: The appli -
cable logistics and operate-to procedures for the 
system describe such things as handling, trans -
portation, maintenance, long-term storage, and operational considerations for the particular design solution.
Other outputs may include:
• Human Systems Integration Plan:  The system 
HSI Plan should be updated to indicate the numbers, skills, and development (i.e., training) 
required for humans throughout the full life cycle 
deployment and operations of the system.764.0 System Design Processes
4.4.2   Design Solution Definition 
Guidance
Refer to Section 4.4.2 in the NASA Expanded 
Guidance for Systems Engineering at https://nen.nasa.

Guidance
gov/web/se/doc-repository  for additional guidance on:
• technology assessment,
• human capability assessment, and
• integrating engineering specialties into the SE process.77
NASA SYSTEMS ENGINEERING HANDBOOK5.0Product Realization
This chapter describes the activities in the prod -
uct realization processes listed in FIGURE 2.1-1 . 
The chapter is separated into sections corresponding 
to steps 5 through 9 listed in FIGURE 2.1-1 . The pro -
cesses within each step are discussed in terms of the inputs, the activities, and the outputs. Additional guidance is provided using examples that are relevant to NASA projects.
In the product realization side of the SE engine, five 
interdependent processes result in systems that meet the design specifications and stakeholder expecta -
tions. These products are produced, acquired, reused, or coded; integrated into higher level assemblies; ver -
ified against design specifications; validated against stakeholder expectations; and transitioned to the next level of the system. As has been mentioned in previous sections, products can be models and simu -
lations, paper studies or proposals, or hardware and software. The type and level of product depends on the phase of the life cycle and the product’s specific objectives. But whatever the product, all should effec -
tively use the processes to ensure the system meets the intended operational concept.
This effort starts with the technical team taking the 
output from the system design processes and using the appropriate crosscutting functions, such as data and configuration management, and technical assess -
ments to make, buy, or reuse subsystems. Once these subsystems are realized, they should be integrated to the appropriate level as designated by the appropri -
ate interface requirements. These products are then verified through the Technical Assessment Process to ensure that they are consistent with the technical data package and that “the product was built right.” Once consistency is achieved, the technical team validates the products against the stakeholder expectations to ensure that “the right product was built.” Upon successful completion of validation, the products are transitioned to the next level of the system. 
FIGURE 
5.0-1 illustrates these processes.
This is an iterative and recursive process. Early in the life cycle, paper products, models, and simulations are run through the five realization processes. As the system matures and progresses through the life cycle, hardware and software products are run through these processes. It is important to detect as many errors and failures as possible at the lowest level of integration and early in the life cycle so that changes can be made through the design processes with min -
imum impact to the project.785.0 Product Realization
The next sections describe each of the five product 
realization processes and their associated products for a given NASA mission.DESIGN REALIZATIONPRODUCT
TRANSITION
PROCESSEVALUATION PROCESSES
• Acquire
• Make/Code
• ReuseProduct
ImplementationProduct
IntegrationProduct
VerificationProduct
ValidationProduct
Transition
• Assembly
• Functional
Evaluation• Functional
• Environmental
• Operational Test-ing in Integration
& Test Environment• Operational Testing in MissionEnvironment• Delivery to Next
Higher Level in PBS
• Delivery to OperationalSystem
FIGURE 5.0-1 Product Realization
PRODUCT REALIZATION KEYS
• Define and execute production activities.
• Genera
te and manage requirements for off-the-shelf hardware/software products as for all other products.
• Unders
tand the differences between verification testing and validation testing.
• Consid
er all customer, stakeholder, technical, programmatic, and safety requirements when evaluating 
the input necessary to achieve a successful product transition.
• Analyz
e for any potential incompatibilities with interfaces as early as possible.
• Comple
tely understand and analyze all test data for trends and anomalies.
• Unders
tand the limitations of the testing and any assumptions that are made.
• Ensure t
hat a reused product meets the verification and validation required for the relevant system in 
which it is to be used, as opposed to relying on the original verification and validation it met for the 
system of its original use. Then ensure that it meets the same verification and validation as a purchased product or a built product. The “pedigree” of a reused product in its original application should not be relied upon in a different system, subsystem, or application.
from the bottom of the product hierarchy up towards 
5.1 Product Implementation
Product implementation is the first process encoun -
tered in the SE engine that begins the movement th
e Product Transition Process. This is where the 
plans, designs, analysis, requirements development, 
and drawings are realized into actual products.
Product implementation is used to generate a speci -
fied product of a project or activity through buying, 
making/coding, or reusing previously developed 795.0 Product Realization
hardware, software, models, or studies to generate a 
product appropriate for the phase of the life cycle. The product should satisfy the design solution and its specified requirements.
The Product Implementation Process is the key activ -
ity that moves the project from plans and designs 
into realized products. Depending on the project and life cycle phase within the project, the product may be hardware, software, a model, simulations, mock-ups, study reports, or other tangible results. These products may be realized through their purchase from commercial or other vendors, through partial or complete reuse of products from other projects or activities, or they may be generated from scratch. The decision as to which of these realization strategies or combination of strategies will be used for the prod -
ucts of this project will have been made early in the life cycle using the Decision Analysis Process.5.1.1 Process Description
FIGURE 5.1-1  provides a typical flow diagram for 
the Product Implementation Process and identifies typical inputs, outputs, and activities to consider in addressing product implementation.
5.1.1.1 Inputs
Inputs to the Product Implementation Process depend primarily on the decision about whether the end product will be purchased, developed from scratch, or formed by reusing part or all of products from other projects. Typical inputs are shown in 
FIGURE 5.1-1 .End Product
Documents a nd
Manuals From Configuration
Management ProcessDesired End
Product To Product
Verification Process
End Product Design
Specifications and
Configuration
Documentation 
Product
Implementation–
Enabling Products To Technical Data
Management Process
Product
Work Products From existing
resou rces or Pr oduct
Transition ProcessRequired Raw
Materials From existing
resour ces or
external sources 
Make the specified end product
Capture work products from product
implementation activitiesPrepare to conduct implementation
If implemented by 
buying:
Participate in purchase
of specified end product
Prepare appropriate
product support documentation If implemented by
reuse:
Participate in acquiring
the reuse end product If implemented by making:
Evaluate readiness of
product implementation–
enabling products 
FIGURE 5.1-1  Prod uct Implementation Process
• Inputs If Purchasing the End Product: If the 
decision was made to purchase part or all of the products for this project, the end product design specifications are obtained from the configura -
tion management system as well as other appli -
cable documents.805.0 Product Realization
• Inputs If Making/Coding the End Product:  For 
end products that will be made/coded by the 
technical team, the inputs will be the config -
uration-controlled design specifications, man -
ufacturing plans, manufacturing processes, manufacturing procedures, and raw materials as provided to or purchased by the project.
• Inputs Needed If Reusing an End Product: For 
end products that will reuse part or all of prod -
ucts generated by other projects, the inputs may 
be the documentation associated with the product 
as well as the product itself. Care should be taken to ensure that these products will indeed meet the specifications and environments for this project. These would have been factors involved in the Decision Analysis Process to determine the make/
buy/reuse decision.
• Enabling Products: These would be any enabling 
products necessary to make, code, purchase, or 
reuse the product (e.g., drilling fixtures, produc -
tion facilities, production lines, software devel -
opment facilities, software test facilities, system integration and test facilities).
5.1.1.2  Process Activities
Implementing the product can take one of three forms:
1. Purchase/buy
2. Make/code
3. Reuse
These three forms will be discussed in the following 
subsections. FIGURE 5.1-1  shows what kind of inputs, 
outputs, and activities are performed during product 
implementation regardless of where in the product

3. Reuse
implementation regardless of where in the product 
hierarchy or life cycle it is. These activities include pre -
paring to conduct the implementation, purchasing/making/reusing the product, and capturing the prod -
uct implementation work product. In some cases, 
implementing a product may have aspects of more than one of these forms (such as a build-to-print). In those cases, the appropriate aspects of the applicable 
forms are used.
5.1.1.2.1 Prepare to Conduct Implementation
Preparing to conduct the product implementation 
is a key first step regardless of what form of imple -
mentation has been selected. For complex projects, 
implementation strategy and detailed planning or 
procedures need to be developed and documented. For less complex projects, the implementation strat -
egy and planning need to be discussed, approved, and documented as appropriate for the complexity of the project.
The documentation, specifications, and other inputs 
also need to be reviewed to ensure they are ready and at an appropriate level of detail to adequately complete the type of implementation form being employed and 
for the product life cycle phase. For example, if the 
“make” implementation form is being employed, the design specifications need to be reviewed to ensure they are at a design-to level that allows the product to be developed. If the product is to be bought as a pure Commercial Off-the-Shelf (COTS) item, the 
specifications need to be checked to make sure they 
adequately describe the vendor characteristics to nar -
row to a single make/model of their product line.
Finally, the availability and skills of personnel needed 
to conduct the implementation as well as the avail -
ability of any necessary raw materials, enabling prod -
ucts, or special services should also be reviewed. Any 
special training necessary for the personnel to per -
form their tasks needs to be performed by this time. This is a key part of the Acceptance Data Package.815.0 Product Realization
5.1.1.2.2 Purchase, Make, or Reuse the Product
Purchase the Product
In the first case, the end product is to be purchased 
from a commercial or other vendor. Design/purchase specifications will have been generated during require -
ments development and provided as inputs. The tech -
nical team needs to review these specifications and ensure they are in a form adequate for the contract or purchase order. This may include the generation of contracts, Statements of Work (SOWs), requests for proposals, purchase orders, or other purchasing 
mechanisms. For major end products purchased from 
a vendor, the responsibilities of the Government and contractor team should be documented in the SEMP and Integration Plan. This will define, for example, whether NASA expects the vendor to provide a fully 
verified and validated product or whether the NASA 
technical team will be performing those duties. The team needs to work with the acquisition team to ensure the accuracy of the contract SOW or purchase order and to ensure that adequate documentation, certificates of compliance, or other specific needs are 
requested from the vendor.
For contracted purchases, as proposals come back 
from the vendors, the technical team should work with the contracting officer and participate in the 
review of the technical information and in the selec-
tion of the vendor that best meets the design require -
ments for acceptable cost and schedule.
As the purchased products arrive, the technical team 
should assist in the inspection of the delivered prod -
uct and its accompanying documentation. The team should ensure that the requested product was indeed the one delivered, and that all necessary documenta -
tion, such as source code, operator manuals, certifi -
cates of compliance, safety information, or drawings 
have been received.The NASA technical team should also ensure that 
any enabling products necessary to provide test, operations, maintenance, and disposal support for the product are also ready or provided as defined in the contract.
Depending on the strategy and roles/responsibilities 
of the vendor, a determination/analysis of the ven -
dor’s verification and validation compliance may need to be reviewed. This may be done informally or formally as appropriate for the complexity of the 
product. For products that were verified and validated 
by the vendor, after ensuring that all work products from this phase have been captured, the product may be ready to enter the Product Transition Process to be delivered to the next higher level or to its final end 
user. For products that the technical team will verify 
and validate, the product will be ready for verification after ensuring that all work products for this phase have been captured.
Make/Code the Product
If the strategy is to make or code the product, the technical team should first ensure that the enabling products are ready. This may include ensuring all 
piece parts are available, drawings are complete and 
adequate, software design is complete and reviewed, machines to cut the material are available, interface specifications are approved, operators are trained and available, manufacturing and/or coding procedures/processes are ready, software personnel are trained 
and available to generate code, test fixtures are devel -
oped and ready to hold products while being gener -
ated, and software test cases are available and ready to 
begin model generation.
The product is then made or coded in accordance 
with the specified requirements, configuration docu -
mentation, and applicable standards. Software devel -
opment must be consistent with NPR 7150.2, NASA Software Engineering Requirements. Throughout 825.0 Product Realization
this process, the technical team should work with the 
quality organization to review, inspect, and discuss progress and status within the team and with higher 
levels of management as appropriate. Progress should 
be documented within the technical schedules. Peer reviews, audits, unit testing, code inspections, simu -
lation checkout, and other techniques may be used to ensure the made or coded product is ready for the verification process. Some production and coding 
can also be separately contracted. This is sometimes 
pursued as a cost control feature providing motiva -
tion for the design contractor to keep the operations costs low and not roll costs into the operations phase of a long-term contract. This is also valuable when 
the design contractor is not well suited for long-term 
continuing production operations. Small projects and activities often use small manufacturing shops to fabricate the system or major portions and small software companies to code their software. In these cases, the production and software engineers may 
specify some portion of the hardware production or 
software coding and request the remaining portions, including as-built documentation, from the man -
ufacturing or software provider. The specified por -
tions are contained as part of the contract statement 
of work in these cases. The level of process control 
and information provided to or from the vendor is dependent on the criticality of the systems obtained. As production proceeds and components are pro -
duced, there is a need to establish a method (Material Review Boards (MRBs) are typically used for large 
projects) to review any nonconformance to specifica -
tions and disposition whether the components can be 
accepted, reworked, or scrapped and remade.
Reuse
If the strategy is to reuse a product that already exists, extreme care should be taken to ensure that the product is truly applicable to this project and for 
the intended uses and the environment in which it 
will be used. This should have been a major factor used in the decision strategy to make/buy/reuse. If 
the new environment is more extreme, requalifica -
tion is needed for the component or system. Design 
factors of safety, margins, and other required design and construction standards should also be assessed. If the program/project requires higher factor of safety 
or margins, the component may not be usable or a 
waiver may have to be approved.
The documentation available (e.g., as-built documen -
tation, user’s guides, operations manuals, discrep -
ancy reports, waivers and deviations) from the reuse 
product should be reviewed by the technical team so 
that they can become completely familiar with the product and ensure it will meet the requirements in the intended environment. Any supporting manuals, drawings, or other documentation available should 
also be gathered.
The availability of any supporting or enabling prod -
ucts or infrastructure needed to complete the fabrica -
tion, coding, testing, analysis, verification, validation, 
or shipping of the product needs to be determined. 
Supporting products may be found in product man -
ufacturing plans, processes, and procedures. If any of

ufacturing plans, processes, and procedures. If any of 
these products or services are lacking, they will need to be developed or arranged for before progressing to the next phase.
Special arrangements may need to be made or forms 
such as nondisclosure agreements may need to be acquired before the reuse product can be received.
A reused product often needs to undergo the same 
verification and validation as a purchased product 
or a built product. Relying on prior verification and validation should only be considered if the product’s verification and validation documentation meets or exceeds the verification, validation, and documen -
tation requirements of the current project and the documentation demonstrates that the product was 835.0 Product Realization
verified and validated against equivalent require -
ments (including environments) and expectations. 
The savings gained from reuse is not necessarily from 
reduced acceptance-level testing of the flight prod -
ucts, but possibly elimination of the need to fully 
requalify the item (if all elements are the same, includ -
ing the environment and operation), elimination of the need to specify all of the internal requirements such as printed circuit board specifications or mate -
rial requirements, reduced internal data products, or the confidence that the item will pass acceptance test and will not require rework.
5.1.1.2.3  Capture Work Products
Regardless of what implementation form was selected, all work products from the make/buy/reuse process should be captured, including as-built design draw -
ings, design documentation, design models, code list -
ings, model descriptions, procedures used, operator manuals, maintenance manuals, or other documen -
tation as appropriate.
5.1.1.3  Outputs
• End Product for Verification:  Unless the vendor 
performs verification, the made/coded, purchased, or reused end product in a form appropriate for 
the life cycle phase is provided for the verification 
process. The form of the end product is a function of the life cycle phase and the placement within the system structure (the form of the end product could be hardware, software, model, prototype, first article for test, or single operational article or 
multiple production articles).
• End Product Documents and Manuals: 
Appropriate documentation is also delivered 
with the end product to the verification process and to the technical data management process. 
Documentation may include applicable as-built 
design drawings; close out photos; operation, user, maintenance, or training manuals; applicable baseline documents (configuration information such as as-built specifications or stakeholder expectations); certificates of compliance; or other vendor documentation.
• Product Implementation Work Products: Any 
additional work products providing reports, records, lesson learned, assumptions, updated CM 
products, and other outcomes of these activities.
The process is complete when the following activities 
have been accomplished:
• End products are fabricated, purchased, or reuse modules are acquired.
• End products are reviewed, checked, and ready for verification.
• Procedures, decisions, assumptions, anomalies, corrective actions, lessons learned, etc., resulting from the make/buy/reuse are recorded.
5.1.2   Product Implementation 
Guidance
Refer to Section 5.1.2 in the NASA Expanded 
ance on:
• buying off-the-shelf products and
• the need to consider the heritage of products.
5.2 Product Integration
Product integration is a key activity of the systems engineer. Product integration is the engineering of the subsystem interactions and their interactions 
with the system environments (both natural and 
induced). Also in this process, lower-level products are assembled into higher-level products and checked 845.0 Product Realization
to make sure that the integrated product functions 
properly and that there are no adverse emergent behaviors. This integration begins during concept 
definition and continues throughout the system life 
cycle. Integration involves several activities focused on the interactions of the subsystems and environ -
ments. These include system analysis to define and understand the interactions, development testing including qualification testing, and integration with 
external systems (e.g., launch operations centers, 
space vehicles, mission operations centers, flight con -
trol centers, and aircraft) and objects (i.e., planetary bodies or structures). To accomplish this integration, the systems engineer is active in integrating the dif -
ferent discipline and design teams to ensure system and environmental interactions are being properly balanced by the differing design teams. The result of a well-integrated and balanced system is an elegant design and operation.
Integration begins with concept development, ensur -
ing that the system concept has all necessary func -
tions and major elements and that the induced and 
natural environment domains in which the system is expected to operate are all identified. Integration 
continues during requirements development, ensur -
ing that all system and environmental requirements 
are compatible and that the system has a proper bal -
ance of functional utility to produce a robust and efficient system. Interfaces are defined in this phase and are the pathway of system interactions. Interfaces 
include mechanical (i.e., structure, loads), fluids, 
thermal, electrical, data, logical (i.e., algorithms and software), and human. These interfaces may include support for assembly, maintenance, and testing func -
tions in addition to the system main performance 
functions. The interactions that occur through all of 
these interfaces can be subtle and complex, leading to both intended and unintended consequences. All of these interactions need to be engineered to produce an elegant and balanced system.Integration during the design phase continues the engineering of these interactions and requires con -
stant analysis and management of the subsystem 
functions and the subsystem interactions between 
themselves and with their environments. Analysis of the system interactions and managing the balance of the system is the central function of the systems engineer during the design process. The system needs to create and maintain a balance between the sub -
systems, optimizing the system performance over any one subsystem to achieve an elegant and efficient design. The design phase often involves development testing at the component, assembly, or system level. This is a key source of data on system interactions, 
and the developmental test program should be struc -
tured to include subsystem interactions, human-in-
the-loop evaluations, and environmental interaction test data as appropriate.
Integration continues during the operations phase, 
bringing together the system hardware, software, and 
human operators to perform the mission. The inter -
actions between these three integrated natures of the system need to be managed throughout development and into operations for mission success. The systems 
engineer, program manager, and the operations team 
(including the flight crew from crewed missions) need to work together to perform this management. The systems engineer is not only cognizant of these oper -
ations team interactions, but is also involved in the design responses and updates to changes in mission 
parameters and unintended consequences (through 
fault management).
Finally, integration or de-integration occurs during 
system closeout (i.e., decommissioning and disposal). 
The system capabilities to support de-integration 
and/or disposal need to be engineered into the sys -
tem from the concept definition phase. The closeout phase involves the safe disposal of flight assets con -
sistent with U.S. policy and law and international 855.0 Product Realization
treaties. This disposal can involve the safe reentry and 
recovery or impact in the ocean, impact on the moon, or solar trajectory. This can also involve the disassem -
bly or repurposing of terrestrial equipment used in manufacturing, assembly, launch, and flight opera -
tions. Dispositioning of recovered flight assets also occurs during this phase. Capture of system data and archiving for use in future analysis also occurs. In all of these activities, the systems engineer is involved 
in ensuring a smooth and logical disassembly of the 
system and associated program assets.
The Product Integration Process applies not only 
to hardware and software systems but also to ser -
vice-oriented solutions, requirements, specifications, plans, and concepts. The ultimate purpose of prod -
uct integration is to ensure that the system elements function as a whole.
Product integration involves many activities that need 
to be planned early in the program or project in order

to be planned early in the program or project in order 
to effectively and timely accomplish the integration. Some integration activities (such as system tests) can require many years of work and costs that need to be identified and approved through the budget cycles. 
An integration plan should be developed and doc -
umented to capture this planning. Small projects 
and activities may be able to include this as part of their SEMP. Some activities may have their integra -
tion plans captured under the integration plan of the sponsoring flight program or R&T program. Larger 
programs and projects need to have a separate inte -
gration plan to clearly lay out the complex analysis 
and tests that need to occur. An example outline for a separate integration plan is provided in 
Appendix H .
During project closeout, a separate closeout plan 
should be produced describing the decommission -
ing and disposal of program assets. (For example, 
see National Space Transportation System (NSTS) 60576, Space Shuttle Program, Transition Management Plan). For smaller projects and activities, particularly 
with short life cycles (i.e., short mission durations), the closeout plans may be contained in the SEMP.
5.2.1  Process Description
FIGURE 5.2-1  provides a typical flow diagram for the 
Product Integration Process and identifies typical inputs, outputs, and activities to consider in address -
ing product integration. The activities of the Product Integration Process are truncated to indicate the action and object of the action.
5.2.1.1  Inputs
• Lower-level products to be integrated: These are 
the products developed in the previous lower-level tier in the product hierarchy. These products will 
be integrated/assembled to generate the product 
for this product layer.
• End product design specifications and config -
uration documentation: These are the specifi -
cations, Interface Control Documents (ICDs), drawings, integration plan, procedures, or other 
documentation or models needed to perform the 
integration including documentation for each of the lower-level products to be integrated.
• Product integration-enabling products:  These 
would include any enabling products, such as holding fixtures, necessary to successfully inte -
grate the lower-level products to create the end product for this product layer.
5.2.1.2  Process Activities
This subsection addresses the approach to the imple -
mentation of the Product Integration Process, includ -
ing the activities required to support the process. The 
basic tasks that need to be established involve the 
management of internal and external interactions of the various levels of products and operator tasks to support product integration and are as follows:865.0 Product Realization
Produc t Documents
and Manuals To Product
Verification ProcessLower Level
Produc ts to Be
Integrated  
Documentation  
Product Integration–
Enabling ProductsTo Technical Data
Management ProcessFrom Pro duct
Transition Process
From Configuration
From existing
resou rces  or Pro duct
Transition ProcessIntegrated Product
Product Integration
Work Products  Confirm that received products
have been  validated 
Prepare the integration environment
for assembly and integration
Assemble and integrate the
received products into the desired
end productObtain lower level products for
assembly and integration 
product integration activitiesPrepare to conduct product
integration
Prepare appropriate product
support documentation 
FIGURE 5.2-1  Product Integration Process
5.2.1.2.1  Prepare to Conduct Product Integration
Prepare to conduct product integration by (1) review -
ing the product integration strategy/plan (see Section 
6.1.2.4.4), generating detailed planning for the inte -
gration, and developing integration sequences and procedures; and (2) determining whether the prod -
uct configuration documentation is adequate to con -
duct the type of product integration applicable for the product life cycle phase, location of the product in the system structure, and management phase suc -
cess criteria.
An integration strategy is developed and documented 
in an integration plan. This plan, as well as support -
ing documentation, identifies the optimal sequence of receipt, assembly, and activation of the various components that make up the system. This strategy should use technical, cost, and schedule factors to ensure an assembly, activation, and loading sequence that minimizes cost and assembly difficulties. The larger or more complex the system or the more deli -
cate the element, the more critical the proper sequence becomes, as small changes can cause large impacts on project results.
The optimal sequence of assembly is built from the 
bottom up as components become sub-elements, elements, and subsystems, each of which should be checked prior to fitting it into the next higher assem -
bly. The sequence will encompass any effort needed 875.0 Product Realization
to establish and equip the assembly facilities; e.g., 
raised floor, hoists, jigs, test equipment, input/out -
put, and power connections. Once established, the 
sequence should be periodically reviewed to ensure 
that variations in production and delivery schedules have not had an adverse impact on the sequence or compromised the factors on which earlier decisions were made.
5.2.1.2.2   Obtain Lower-Level Products for Assembly 
and Integration
Each of the lower-level products that is needed for 
assembly and integration is obtained from the tran -
sitioning lower-level product owners or a storage 
facility as appropriate. Received products should be 
inspected to ensure no damages occurred during the transitioning process.
5.2.1.2.3   Confirm That Received Products Have Been 
Validated
Confirm that the received products that are to be 
assembled and integrated have been validated to demonstrate that the individual products satisfy the 
agreed-to set of stakeholder expectations, including 
interface requirements. This validation can be con -
ducted by the receiving organization or by the pro -
viding organization if fully documented or witnessed by the receiving representative.
5.2.1.2.4   Prepare the Integration Environment for 
Assembly and Integration
Prepare the integration environment in which assem -
bly and integration will take place, including evaluat -
ing the readiness of the product integration-enabling 
products and the assigned workforce. These enabling 
products may include facilities, equipment jigs, tool -
ing, and assembly/production lines. The integration environment includes test equipment, simulators, models, storage areas, and recording devices.5.2.1.2.5   Assemble and Integrate the Received Products 
into the Desired End Product
Assemble and integrate the received products into 
the desired end product in accordance with the spec -
ified requirements, configuration documentation, 
interface requirements, applicable standards, and 
integration sequencing and procedures. This activ -
ity includes managing, evaluating, and controlling physical, functional, and data interfaces among the products being integrated.
Functional testing of the assembled or integrated 
unit is conducted to ensure that assembly is ready to enter verification testing and ready to be integrated into the next level. Typically, all or key representative functions are checked to ensure that the assembled 
system is functioning as expected. Formal product 
verification and validation will be performed in the next process.
5.2.1.2.6   Prepare Appropriate Product Support  
Documentation
Prepare appropriate product support documentation, such as special procedures for performing product verification and product validation. Drawings or 
accurate models of the assembled system are devel -
oped and confirmed to be representative of the 
assembled system.
5.2.1.2.7  Capture Product Integration Work Products
Capture work products and related information generated while performing the Product Integration Process activities. These work products include system 
models, system analysis data and assessment reports, 
derived requirements, the procedures that were used in the assembly, decisions made and supporting ratio -
nale, assumptions that were made, identified anoma -
lies and associated corrective actions, lessons learned in performing the assembly, and updated product 
configuration and support documentation.885.0 Product Realization
5.2.1.3  Outputs
The following are typical outputs from this process 
and destinations for the products from this process:
• Integrated product(s)  with all system interactions 
identified and properly balanced.
• Documentation and manuals , including system 
analysis models, data, and reports supporting flight-readiness rationale and available for future 
analysis during the operation of the system in the 
mission-execution phase.

• Work products , including reports, records, and 
non-deliverable outcomes of product integra -
tion activities (to support the Technical Data 
Management Process); integration strategy doc -
ument; assembly/check area drawings; system/
component documentation sequences and ratio -
nale for selected assemblies; interface manage -
ment documentation; personnel requirements; special handling requirements; system documen -
tation; shipping schedules; test equipment and drivers’ requirements; emulator requirements; and identification of limitations for both hard -
ware and software.
5.2.2  Product Integration Guidance
Refer to Section 5.2.2 in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.
• product integration strategies,
• the relationship to product implementation,
• product integration support,
• product integration of the design solution,
• system analysis, and
• interface system integration.5.3 Product Verification
The Product Verification Process is the first of the verification and validation processes conducted on an end product. As used in the context of the systems 
engineering common technical processes, a product 
is one provided by either the Product Implementation Process or the Product Integration Process in a form suitable for meeting applicable life cycle phase success criteria. Realization is the act of implementing, inte -
grating, verifying, validating, and transitioning the 
end product for use at the next level up of the system 
structure or to the customer. At this point, the end product can be referred to as a “realized product” or “realized end product.”
Product verification proves that an end product 
(whether built, coded, bought, or reused) for any element within the system structure conforms to its requirements or specifications. Such specifications and other design description documentation estab -
lish the configuration baseline of that product, which 
may have to be modified at a later time. Without a 
verified baseline and appropriate configuration con -
trols, such later modifications could be costly or cause major performance problems.
From a process perspective, product verification and 
validation may be similar in nature, but the objec -
tives are fundamentally different. A customer is inter -
ested in whether the end product provided will do what the customer intended within the environment of use. Examination of this condition is validation. 
Simply put, the Product Verification Process answers 
the critical question, “Was the end product realized right?” The Product Validation Process addresses the equally critical question, “Was the right end prod -
uct realized?” When cost effective and warranted by 
analysis, the expense of validation testing alone can 
be mitigated by combining tests to perform verifica -
tion and validation simultaneously.895.0 Product Realization
The outcome of the Product Verification Process is con -
firmation that the end product, whether achieved by 
implementation or integration, conforms to its speci -
fied requirements, i.e., verification of the end product. This subsection discusses the process activities, inputs, outcomes, and potential product deficiencies.DIFFERENCES BETWEEN VERIFICATION AND VALIDATION TESTING
Testing is a detailed evaluation method of both verification and validation
Verification Testing:  Verification testing relates back to the approved requirements set (such as an SRD) 
and can be performed at different stages in the product life cycle. Verification tests are the official “for 
the record” testing performed on a system or element to show that it meets its allocated requirements or specifications including physical and functional interfaces. Verification tests use instrumentation and measurements and are generally accomplished by engineers, technicians, or operator-maintainer test personnel in a controlled environment to facilitate failure analysis.
Validation Testing:  Validation relates back to the ConOps document. Validation testing is conducted 
under realistic conditions (or simulated conditions) on any end product to determine the effectiveness and 
suitability of the product for use in mission operations by typical users and to evaluate the results of such tests. It ensures that the system is operating as expected when placed in a realistic environment.
5.3.1  Process Description
FIGURE 5.3-1 , taken from NPR 7123.1, provides a typ -
ical flow diagram for the Product Verification Process 
and identifies typical inputs, outputs, and activities to consider in addressing product verification.
5.3.1.1  Inputs
Key inputs to the process are:
• The product to be verified: This product 
will have been transitioned from either the Product Implementation Process or the Product Integration Process. The product will likely have been through at least a functional test to ensure it was assembled correctly. Any supporting doc -
um
entation should be supplied with the product.
• Verification plan: This plan will have been devel -
oped under the Technical Planning Process and baselined before entering this verification.
• Specified requirements baseline:  These are the 
requirements that have been identified to be verified for this product. Acceptance criteria should have been identified for each requirement to be verified.
• Enabling products:  Any other products needed 
to perform the Product Verification Process. This may include test fixtures and support equipment.
Additional work products such as the ConOps, mis-sion needs and goals, interface control drawings, test -
ing standards and policies, and Agency standards and policies may also be needed to put verification activ -
ities into context.905.0 Product Realization
DIFFERENCES BETWEEN VERIFICATION, QUALIFICATION, 
ACCEPTANCE AND CERTIFICATION
Verification: Verification is a formal process, using the method of test, analysis, inspection or 
demonstration, to confirm that a system and its associated hardware and software components satisfy all specified requirements. The Verification program is performed once regardless of how many flight units may be generated (as long as the design doesn’t change).
Qualification: Qualification activities are performed to ensure that the flight unit design will meet functional 
and performance requirements in anticipated environmental conditions. A subset of the verification program is performed at the extremes of the environmental envelope and will ensure the design will operate properly with the expected margins. Qualification is performed once regardless of how many flight units may be generated (as long as the design doesn’t change).
Acceptance : smaller subset of the verification program is selected as criteria for the acceptance program. 
The selected Acceptance activities are performed on each of the flight units as they are manufactured and 
readied for flight/use. An Acceptance Data Package is prepared for each of the flight units and shipped with the unit. The acceptance test/analysis criteria are selected to show that the manufacturing/workmanship of the unit conforms to the design that was previously verified/qualified. Acceptance testing is performed for each flight unit produced.
Certification: Certification is the audit process by which the body of evidence that results from the 
verification activities and other activities are provided to the appropriate certifying authority to indicate the design is certified for flight/use. The Certification activity is performed once regardless of how many flight units may be generated.
5.3.1.2  Process Activities
There are five major activities in the Product 
Verification Process: (1) prepare to conduct prod -
uct verification; (2) perform verification; (3) analyze verification results; (4) preparing a product verifica -
tion report; and (5) capture work products generated during the verification activities.
Product Verification is often performed by the devel -
oper that produced the end product with participa -
tion of the end user and customer. Quality Assurance (QA) personnel are also critical in the verification 
pla
nning and execution activities.
A verification approach should be adapted (tailored) to the project it supports. The project manager and systems engineer should work with the verification lead engineer to develop a verification approach and plan the activities. Many factors need to be consid -
ered in developing this approach and the subsequent verification program. These factors include:915.0 Product Realization
• Project type, especially for flight projects. 
Verification activities and timing depend on the following:
 »The type of flight article involved (e.g., an experiment, payload, or launch vehicle).
 »For missions required to follow NPR 7120.5, NASA Space Flight Program and Project Management Requirements, NASA 
payload classification (NPR 8705.4, Risk

pla
payload classification (NPR 8705.4, Risk 
Classification for NASA Payloads) guidelines are intended to serve as a starting point for establishing the formality of verification approaches that can be adapted to the needs of a specific project based on the “A–D” 
payload classification. Further flexibility is 
imparted to projects following NPR 7120.8, NASA Research and Technology Program and Project Management Requirements.Product Verification
Results 
Report  From Pro duct
Implementation or
Product Integra tion  Process
End P roduct
to Be Verified
Plan Specified Requirements
Baseline  
Enabling ProductsTo Technical
Assessment ProcessVerified End Product To Product
Validation Process
Management ProcessFrom Configura ation
resources or Pro duct
Transition ProcessProduct Verification
Work P roducts  Perform the product
verification
Analyze the outcomes of
the product verification
Capture work products from
product verification activitiesPrepare a product
verification reportPrepare to conduct product
FIGURE 5.3-1  P roduct Verification Process
 »Project cost and schedule implications. Verification activities can be significant driv -
ers of a project’s cost and schedule, and these 
implications should be considered early in the 
development of the verification plan. Trade studies should be performed early in the life cycle to support decisions about verification methods and types and the selection of facil -
ity capabilities and locations. For example, a 
trade study might be made to decide between 
performing a test at a centralized facility or at several decentralized locations.
 »Risk management should be considered in the development of the verification approach. Qualitative risk assessments and quantita -
tive risk analyses (e.g., a Failure Mode and Effects Analysis (FMEA)) often identify new concerns that can be mitigated by additional verifications, thus increasing the extent of 925.0 Product Realization
verification activities. Other risk assessments 
contribute to trade studies that determine 
the preferred methods of verification to be 
used and when those methods should be 
performed. For example, a trade might be 
made between performing a model test versus 
determining model characteristics by a less 
costly but less revealing analysis. The project 
manager/systems engineer should determine 
what risks are acceptable in terms of the proj -
ect’s cost and schedule.
• Availability of verification facilities/sites and 
transportation assets to move an article from one 
location to another (when needed). This requires 
coordination with the Integrated Logistics 
Support (ILS) engineer.
• Availability of appropriately trained users for 
interaction with systems having human interfaces.
• Acquisition strategy; i.e., in-house development or 
system contract. A NASA field Center can often 
shape a contractor’s verification process through 
the project’s SOW.
• Degree of design heritage and hardware/software reuse.
5.3.1.2.1 Product Verification Preparation
In preparation for verification, the verification 
plan and the specified requirements are collected, 
reviewed, and confirmed. The product to be verified 
is obtained (output from the Product Implementation 
Process or the Product Integration Process) along 
with any enabling products, such as those repre -
senting external interfacing products and support 
resources (including personnel) that are necessary for 
verification. Procedures capturing detailed step-by-
step activities and based on the verification type and 
methods are finalized and approved. Development of 
procedures typically begins during the design phase of the project life cycle and matures as the design is 
matured. The verification environment is considered as 
part of procedure development. Operational scenarios 
are assessed to explore all possible verification activities 
to be performed. The final element is preparation of the 
verification environment; e.g., facilities, equipment, 
tools, measuring devices, and climatic conditions.
When operator or other user interaction is involved, 
it is important to ensure that humans are properly 
represented in the verification activities. This includes 
physical size, skills, knowledge, training, clothing, 
special gear, and tools. Note: Testing that includes 
representatives of the human in the system is often 
referred to as “human-in-the-loop” testing.
NOTE: Depending on the nature of the verifica -
tion effort and the life cycle phase the program is in, 
some type of review to assess readiness for verifi -
cation (as well as validation later) is typically held. In 
earlier phases of the life cycle, these Test Readiness 
Reviews (TRRs) may be held informally; in later 
phases of the life cycle, this review may become a 
more formal event. TRRs and other technical reviews 
are an activity of the Technical Assessment Process.
On most projects, a number of TRRs with tailored 
entrance/success criteria are held to assess the 
readiness and availability of test ranges, test facili -
ties, trained testers, instrumentation, integration labs, 
support equipment, and other enabling products.
Peer reviews are additional reviews that may be 
conducted formally or informally to ensure readiness 
for verification (as well as the results of the verifi -
cation process). Guidelines for conducting a peer 
review are discussed in Section 6.7.2.4.5.
TABLE 5.3-1 provides an example of the type of infor -
mation that may be included in a verification proce -
dure and a verification report.935.0 Product Realization
METHODS OF VERIFICATION
Analysis:  The use of mathematical modeling and analytical techniques to predict the suitability of a 
design to stakeholder expectations based on calculated data or data derived from lower system structure 
end product verifications. Analysis is generally used when a prototype; engineering model; or fabricated, assembled, and integrated product is not available. Analysis includes the use of modeling and simulation as analytical tools. A model is a mathematical representation of reality. A simulation is the manipulation of a model. Analysis can include verification by similarity of a heritage product.
Demonstration:  Showing that the use of an end product achieves the individual specified requirement. 
It is generally a basic confirmation of performance capability, differentiated from testing by the lack of 
detailed data gathering. Demonstrations can involve the use of physical models or mock-ups; for example, a requirement that all controls shall be reachable by the pilot could be verified by having a pilot perform flight-related tasks in a cockpit mock-up or simulator. A demonstration could also be the actual operation of the end product by highly qualified personnel, such as test pilots, who perform a one-time event that demonstrates a capability to operate at extreme limits of system performance, an operation not normally expected from a representative operational pilot.
Inspection:  The visual examination of a realized end product. Inspection is generally used to verify physical 
design features or specific manufacturer identification. For example, if there is a requirement that the safety 
arming pin has a red flag with the words “Remove Before Flight” stenciled on the flag in black letters, a visual inspection of the arming pin flag can be used to determine if this requirement was met. Inspection can include inspection of drawings, documents, or other records.
Test: The use of an end product to obtain detailed data needed to verify performance or provide sufficient 
information to verify performance through further analysis. Testing can be conducted on final end products, breadboards, brassboards, or prototypes. Testing produces data at discrete points for each specified requirement under controlled conditions and is the most resource-intensive verification technique. As the saying goes, “Test as you fly, and fly as you test.” (See Section 5.3.2.5 in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-repository )
Outcomes of verification preparation include the 
following:
• The verification plan, approved procedures, and an appropriate baseline set of specified require -
ments and supporting configuration documenta -
tion is available and on hand;• Articles/models to be verified and verification-en -
abling products are on hand, assembled, and integrated with the verification environment according to verification plans and schedules;
• The resources (funding, facilities, and people including appropriately skilled operators) needed 945.0 Product Realization
TABLE 5.3-1 Example information in Verification Procedures and Reports
Verification Procedure Verification Report
Nomenclature and identification of the test article or

Nomenclature and identification of the test article or 
material;Verification objectives and the degree to which they were 
met;
Identification of test configuration and any differences 
from flight operational configuration;Description of verification activity including deviations 
from nominal results (discrepancies);
Identification of objectives and criteria established for the 
verification by the applicable requirements specification;Test configuration and differences from the flight 
operational configuration;
Characteristics and design criteria to be inspected, 
demonstrated, or tested, including values with tolerances 
for acceptance or rejection;Specific result of each activity and each procedure, 
including the location or link to verification data/artifacts;
Description, in sequence, of steps, operations, and 
observations to be taken;Specific result of each analysis including those associated 
with test-data analysis;
Identification of computer software required; Test performance data tables, graphs, illustrations, and 
pictures;
Identification of measuring, test, and recording equipment 
to be used, specifying range, accuracy, and type;Summary of nonconformance/discrepancy reports, 
including dispositions with approved corrective actions 
and planned retest activity if available;
Provision for recording equipment calibration or software 
version data;Conclusions and recommendations relative to the 
success of verification activity;
Credentials showing that required computer test 
programs/support equipment and software have been 
verified prior to use with flight operational hardware;Status of Government-Supplied Equipment (GSE) and 
other enabling support equipment as affected by test;
Any special instructions for operating data recording 
equipment or other automated test equipment as 
applicable;Copy of the as-run procedure (may include redlines); and
Layouts, schematics, or diagrams showing identification, 
location, and interconnection of test equipment, test 
articles, and measuring points and any other associated 
design or configuration work products;Authentication of test results and authorization of 
acceptability.
Identification of hazardous situations or operations;
Precautions and safety instructions to ensure safety of 
personnel and prevent degradation of test articles and 
measuring equipment;
Environmental and/or other conditions to be maintained 
with tolerances;
Constraints on inspection or testing;
Provision or instructions for the recording of verification 
results and other artifacts;
Special instructions for instances of nonconformance and 
anomalous occurrences or results; and
Specifications for facility, equipment maintenance, 
housekeeping, quality inspection, and safety and handling 
requirements before, during, and after the total verification 
activity.955.0 Product Realization
to conduct the verification are available according 
to the verification plans and schedules; and
• The verification environment is evaluated for ade -
quacy, completeness, readiness, and integration.
5.3.1.2.2 Perform Product Verification
The actual act of verifying the end product is per -
formed as spelled out in the plans and procedures, 
and conformance is established with each specified 
product requirement. The verification lead should 
ensure that the procedures were followed and per -
formed as planned, the verification-enabling prod -
ucts and instrumentation were calibrated correctly, 
and the data were collected and recorded for required 
verification measures.
A verification program may include verifications at 
several layers in the product hierarchy. Some verifica -
tions need to be performed at the lowest component 
level if the ability to verify a requirement at a higher 
assembly is not possible. Likewise, there may be veri -
fications at assemblies, sub-systems and system levels. 
If practicable, a final set of testing with as much of 
the end-to-end configuration as possible is important.
The purpose of end-to-end testing is to demonstrate 
interface compatibility and desired total function -
ality among different elements of a mission system, 
between systems (the system of interest and external 
enabling systems), and within a system as a whole. 
It can involve real or representative input and oper -
ational scenarios. End-to-end tests performed on 
the integrated ground and flight assets include all 
elements of the flight article (payload or vehicle), 
its control, stimulation, communications, and data 
processing to demonstrate that the entire integrated 
mission system is operating in a manner to fulfill all 
mission requirements and objectives. End-to-end tests 
may be performed as part of investigative engineering 
tests, verification testing, or validation testing. These are some of the most important tests for the systems 
engineers to participate in or to lead. They review 
the overall compatibility of the various systems and 
demonstrate compliance with system-level require -
ments and whether the system behaves as expected 
by the stakeholders.
End-to-end testing includes executing complete 
threads or operational scenarios across multi -
ple configuration items, ensuring that all mission 
requirements are verified and validated. Operational 
scenarios are used extensively to ensure that the 
mission system (or collections of systems) will suc -
cessfully execute mission requirements. Operational 
scenarios are a step-by-step description of how the 
system should operate and interact with its users and 
its external interfaces (e.g., other systems). Scenarios 
should be described in a manner that allows engi -
neers to walk through them and gain an understand -
ing of how all the various parts of the system should 
function and interact as well as verify that the system 
will satisfy the user’s goals and expectations (MOEs). 
Operational scenarios should be described for all 
operational modes, mission phases (e.g., installation, 
startup, typical examples of normal and contingency 
operations, shutdown, and maintenance), and critical 
sequences of activities for all classes of users identi -
fied. Each scenario should include events, actions, 
stimuli, information, and interactions as appropri -
ate to provide a comprehensive understanding of the 
operational aspects of the system.
FIGURE 5.3-2  presents an example of an end-to-end 
data flow for a scientific satellite mission. Each arrow 
in the diagram represents one or more data or control 
flows between two hardware, software, subsystem, or 
system configuration items. End-to-end testing veri -
fies that the data flows throughout the multisystem 
environment are correct, that the system provides the 
required functionality, and that the outputs at the 
eventual end points correspond to expected results. 965.0 Product Realization
EXTERNAL
STIMULI
Instrument
Set B X-rays
InfraredVisible
Ultravi olet
MicrowaveInstrument
Set A
Spacecraft
Execution
CommunityMission
Planning
Data
CaptureSoftware
LoadsCommand
GenerationPlanning
ArchivalTransmission
AnalysisUplink Process
Downlink ProcessEXTERNAL
SYSTEMSGROUND SYSTEM FLIGHT SYSTEM
FIGURE 5.3-2  Exa mple of End-to-End Data Flow for a Scientific Satellite Mission
Since the test environment is as close an approxi -
mation as possible to the operational environment, 
system performance requirements testing is also included. This figure is not intended to show the full extent of end-to-end testing. Each system shown would need to be broken down into a further level of granularity for completeness.
End-to-end testing is an integral part of the verifi -
cation and validation of the total (mission) system. 
It is a set of activities that can be employed during selected hardware, software, and system phases throughout the life cycle using developmental forms and external simulators. However, final end-to-end testing should be done on the flight articles in the flight configuration if possible and prior to deploy -
ment and launch. In comparison with configura -
tion item testing, end-to-end testing addresses each configuration item (end product) only down to the level designated by the verification plan (generally, the segment r element) and focuses on external inter -
faces, which can be either hardware, software, or human-based. Internal interfaces (e.g., software sub -
ro
utine calls, analog-to-digital conversion) of a desig -
nated configuration item are not within the scope of end-to-end testing.
When a “discrepancy” is observed (i.e., any variance, 
lack of agreement, or contradiction with the required or expected outcome, configuration, or result), verifi -
cation activities should stop and a discrepancy report should be generated. The activities and events leading up to the discrepancy should be analyzed to deter -
mine if a nonconforming product exists or there is an issue with the verification procedure or conduct. The Decision Analysis Process should be used to make decisions with respect to needed changes in the veri -
fication plans, environment, and/or procedures.
Outcomes of performing product verification include 
the following:

ro
• A verified product is established with supporting confirmation that the product (in the appropriate 975.0 Product Realization
form for the life cycle phase) complies with its 
specified requirements, and if it does not, a non -
conformance report delineating the variance is 
available.
• A determination is made as to whether the appro -
priate results were collected and evaluated to show 
completion of verification objectives throughout 
their performance envelope.
• A determination is made that the verification 
product was appropriately integrated with the 
enabling products and verification environment.
5.3.1.2.3  Analyze Product Verification Results and 
Report
As the verification activities are completed, the 
results are collected and analyzed. The data are ana -
lyzed for quality, integrity, correctness, consistency, 
and validity. Any verification discrepancies (anom -
alies, variations, and out-of-compliance conditions) 
are identified and reviewed to determine if there is a 
nonconforming product not resulting from poor ver -
ification conduct, procedure, or conditions. If possi -
ble, this analysis is performed while the test/analysis 
configuration is still intact. This allows a quick turn -
around in case the data indicates that a correction to 
the test or analysis run needs to be performed again.
Discrepancies and nonconforming products should 
be recorded and reported for follow-up action and 
closure. Verification results should be recorded in 
a requirements compliance or verification matrix 
or other method developed during the Technical 
Requirements Definition Process to trace compliance 
for each product requirement. Waivers needed as a 
result of verification to request relief from or modify 
a requirement are identified.NOTE:  Nonconformance and discrepancy 
reports may be directly linked with the Technical 
Risk Management Process. Depending on the 
nature of the nonconformance, approval through 
such bodies as a Material Review Board or 
Configuration Control Board (which typically 
includes risk management participation) may 
be required.
System design and product realization process activ -
ities may be required to resolve product nonconfor -
mance. If the mitigation of the nonconformance 
results in a change to the product, the verification 
may need to be planned and performed again.
Outcomes of analyzing the verification results include 
• Product nonconformance (not compliant with 
product requirement) is identified.
• Appropriate replanning, redefinition of require -
ments, redesign, implementation/integration, mod -
ification, and reverification have been accomplished 
for resolution of the nonconforming product.
• Appropriate facility modifications, procedure 
corrections, enabling product modification, and 
reverification have been performed for non-prod -
uct-related discrepancies.
• Waivers for nonconforming products are accepted.
• Discrepancy and nonconformance reports including 
corrective actions have been generated as needed.
• The verification report is completed.985.0 Product Realization
Re-engineering
Based on analysis of verification results, it could be 
necessary to re-realize the end product used for ver -
ification or to re-engineer the end products assem -
bled and integrated into the product being verified, 
based on where and what type of nonconformance 
was found.
Re-engineering could require the reapplication of the 
system design processes (Stakeholder Expectations 
Definition Process, Technical Requirements 
Definition Process, Logical Decomposition Process, 
and Design Solution Definition Process).
5.3.1.2.4 Capture Product Verification Work Products
Verification work products (inputs to the Technical 
Data Management Process) take many forms and 
involve many sources of information. The capture 
and recording of verification results and related data 
is a very important, but often underemphasized, step 
in the Product Verification Process.
Verification results, peer review reports, anomalies, 
and any corrective action(s) taken should be captured, 
as should all relevant results from the application of 
the Product Verification Process (related decisions, 
rationale for the decisions made, assumptions, and 
lessons learned).
Outcomes of capturing verification work products 
• Verification of work products is recorded, e.g., 
method of verification, procedures, environ -
ments, outcomes, decisions, assumptions, correc -
tive actions, and lessons learned.
• Variations, anomalies, and out-of-compliance 
conditions have been identified and documented, 
including the actions taken to resolve them.• Proof that the realized end product did or did not 
satisfy the specified requirements is documented.
• The verification report is developed, including:
 »recorded test/verification results/data;
 »version of the set of specified requirements 
used;
 »version of the product verified;
 »version or standard for tools, data, and equip -
ment used;
 »results of each verification including pass or 
fail declarations; and
 »discrepancies.
5.3.1.3 Outputs
Key outputs from the process are:
• Verified product ready for validation: After the 
product is verified, it will next pass through the 
Product Validation Process.
• Product verification results: Results from executed 
procedures are passed to technical assessment.
• Product verification report(s): A report shows the 
results of the verification activities. It includes the 
requirement that was to be verified and its bidi -
rectional traceability, the verification method 
used, and reference to any special equipment, 
conditions, or procedures used. It also includes 
the results of the verification, any anomalies, 
variations or out-of-compliance results noted and 
associated corrective actions taken.
• Product verification work products:  These 
include discrepancy and nonconformance reports 
with identified correction actions; updates 
to requirements compliance documentation; 
changes needed to the procedures, equipment or 995.0 Product Realization
environment; configuration drawings; calibra -
tions; operator certifications; and other records.
Criteria for completing verification of the product 
include: (1) documented objective evidence of com -
pliance with requirements or waiver and (2) closure of all discrepancy and nonconformance reports.
5.3.2  Product Verification Guidance
Refer to Section 5.3.2 in the NASA Expanded Guidance for Systems Engineering at 
• the verification approach,
• verification in the life cycle,
• verification procedures,
• verification reports
• end-to-end testing,
• use of modeling and simulations, and
• hardware-in-the-loop testing.
5.4 Product Validation
The Product Validation Process is the second of the verification and validation processes conducted on an implemented or integrated end product. While veri -
fication proves whether “the product was done right,” validation proves whether “the right product was done.” In other words, verification provides objective evidence that every “shall” statement in the require -
ments document or specification was met, whereas validation is performed for the benefit of the custom -
ers and users to ensure that the system functions in the expected manner when placed in the intended environment. This is achieved by examining the products of the system at every level of the product structure and comparing them to the stakeholder 
expectations for that level. A well-structured valida -
tion process can save cost and schedule while meeting 
the stakeholder expectations.System validation confirms that the integrated real -
ized end products conform to stakeholder expec -
tations as captured in the MOEs, MOPs, and ConOps. Validation also ensures that any anomalies 
discovered are appropriately resolved prior to prod -
uct delivery. This section discusses the process activ -
ities, methods of validation, inputs and outputs, and 
potential deficiencies.
See 
Section 2.4  for a discussion about the distinctions 
between Product Verification and Product Validation.
5.4.1  Process Description
FIGURE 5.4-1 , taken from NPR 7123.1, provides a typ -
ical flow diagram for the Product Validation Process 
and identifies typical inputs, outputs, and activities 
to consider in addressing product validation.
5.4.1.1  Inputs
• End product to be validated: This is the end prod -
uct that is to be validated and which has success -
fully passed through the verification process.
• Validation plan: This plan would have been devel -
oped under the Technical Planning Process and 
baselined prior to entering this process. This plan 
may be a separate document or a section within 
the Verification and Validation Plan.
• Baselined stakeholder expectations: These would

See 
• Baselined stakeholder expectations: These would 
have been developed for the product at this level during the Stakeholder Expectations Definition 
Process. It includes the needs, goals, and objec-
tives as well as the baselined and updated concept of operations and MOEs.
• Any enabling products: These are any special 
equipment, facilities, test fixtures, applications, 1005.0 Product Realization
or other items needed to perform the Product 
Validation Process.
5.4.1.2  Process Activities
The Product Validation Process demonstrates that the end product satisfies its stakeholder (customer and other interested party) expectations (MOEs) within the intended operational environments, with validation performed by anticipated operators and/or users whenever possible. The method of validation is a function of the life cycle phase and the position of the end product within the system structure.
There are five major steps in the validation process: 
(1) preparing to conduct validation, (2) conduct planned validation (perform validation), (3) analyze validation results, (4) prepare a validation report, and (5) capture the validation work products.
From Pro duct
Verification Process To Product
Results 
Report  End Product
to Be Validated 
Plan Stakeholder Expectation
Baseline  
Product Validation–
Assessment Process
From Design Solution 
 and  Technical
Planning ProcessesValidated End Product 
Management ProcessFrom Configuration
resou rces or Pro duct
Transition ProcessProduct V alidation
Work Products  Perform the product
validation
the product validation
Captur e the work  products
from product validation activities Prepare a product
validation report Prepare to conduct product
FIGURE 5.4-1  Pr oduct Validation ProcessThe objectives of the Product Validation Process are:
• To confirm that the end product fulfills its intended use when operated in its intended environment:
 »Validation is performed for each implemented or integrated and verified end product from the lowest end product in a system structure branch up to the top level end product (the system).
 »Evidence is generated as necessary to con -
firm that products at each layer of the sys -
tem structure meet the capability and other operational expectations of the customer/user/operator and other interested parties for that product.1015.0 Product Realization
• To ensure the human has been properly integrated 
into the system:
 »The user interface meets human engineering criteria.
 »Operators and maintainers have the required skills and abilities.
 »Instructions are provided and training pro -
grams are in place.
 »The working environment supports crew health and safety.• To ensure that any problems discovered are appropriately resolved prior to delivery of the end product (if validation is done by the supplier of the product) or prior to integration with other products into a higher level assembled product (if validation is done by the receiver of the product).
METHODS OF VALIDATION
Analysis: The use of mathematical modeling and analytical techniques to predict the suitability of a 
design to stakeholder expectations based on calculated data or data derived from lower system structure end product verifications. Analysis is generally used when a prototype; engineering model; or fabricated, assembled, and integrated product is not available. Analysis includes the use of modeling and simulation as analytical tools. A model is a mathematical representation of reality. A simulation is the manipulation of a model.
Demonstration: Showing that the use of an end product achieves the stakeholder expectations as defined 
in the NGOs and the ConOps. It is generally a basic confirmation of behavioral capability, differentiated from testing by the lack of detailed data gathering. Demonstrations can involve the use of physical models or mock-ups; for example, an expectation that controls are readable by the pilot in low light conditions could be validated by having a pilot perform flight-related tasks in a cockpit mock-up or simulator under those conditions.
Inspection: The visual examination of a realized end product. Inspection is generally used to validate the 
presence of a physical design features or specific manufacturer identification. For example, if there is an expectation that the safety arming pin has a red flag with the words “Remove Before Flight” stenciled on the flag in black letters, a visual inspection of the arming pin flag can be used to determine if this expectation has been met.
Test: The use of an end product to obtain detailed data needed to determine a behavior, or provide 
sufficient information to determine a behavior through further analysis. Testing can be conducted on final end products, breadboards, brassboards, or prototypes. Testing produces information at discrete points for each specified expectation under controlled conditions and is the most resource-intensive validation technique.5.4.1.2.1  Product Validation Preparation
To prepare for performing product validation, the 
appropriate set of expectations, including MOEs and MOPs, against which the validation is to be made 1025.0 Product Realization
should be obtained. In addition to the V&V Plan, 
other documentation such as the ConOps and HSI 
Plan may be useful. The product to be validated (out -
put from implementation, or integration and verifi -
cation), as well as the appropriate enabling products 
and support resources (requirements identified and 
acquisition initiated by design solution activities) 
with which validation will be conducted should be 
collected. Enabling products includes those repre -
senting external interfacing products and special 
test equipment. Support resources include person -
nel necessary to support validation and operators. 
Procedures, capturing detailed step-by-step activities 
and based on the validation type and methods are 
finalized and approved. Development of procedures 
typically begins during the design phase of the proj -
ect life cycle and matures as the design is matured. 
The validation environment is considered as part of 
procedure development. Operational scenarios are 
assessed to explore all possible validation activities to 
be performed. The final element is preparation of the 
validation environment; e.g., facilities, equipment, 
software, and climatic conditions.
represented in the validation activities. This includes 
special gear, and tools. When possible, actual end 
users/operators should be used and other stakeholders 
should participate or observe activities as appropriate 
and practical.
Outcomes of validation preparation include the 
• The validation plan, approved procedures, sup -
porting configuration documentation, and an 
appropriate baseline set of stakeholder expecta -
tions are available and on hand;• Enabling products are integrated within the valida -
tion environment according to plans and schedules;
• Users/operators and other resources are available 
according to validation plans and schedules; and
• The validation environment is evaluated for ade -
5.4.1.2.2 Perform Product Validation
The act of validating the end product is performed 
as spelled out in the validation plans and procedures, 
and the conformance established to each specified 
stakeholder expectation (MOEs and ConOps) shows 
that the validation objectives were met. Validation 
differs from qualification testing. Validation testing is 
focused on the expected environments and operations 
of the system where as qualification testing includes 
the worst case loads and environmental requirements 
within which the system is expected to perform or 
survive. The verification lead should ensure that the 
procedures were followed and performed as planned, 
the validation-enabling products and instrumenta -
tion were calibrated correctly, and the data were col -
lected and recorded for required validation measures.
When a discrepancy is observed, the validation should 
be stopped and a discrepancy report generated. The 
activities and events leading up to the discrepancy 
should be analyzed to determine if a nonconforming 
product exists or there is an issue with the verifica -
tion procedure, conduct, or conditions. If there are 
no product issues, the validation is replanned as nec -
essary, the environment preparation anomalies are 
corrected, and the validation is conducted again with 
improved or correct procedures and resources. The 
Decision Analysis Process should be used to make 
decisions with respect to needed changes to the vali -

dation plans, environment, and/or conduct.1035.0 Product Realization
Outcomes of performing validation include the 
• A validated product is established with support -
ing confirmation that the appropriate results were 
collected and evaluated to show completion of 
validation objectives.
• A determination is made as to whether the fabri -
cated/manufactured or assembled and integrated 
products (including software or firmware builds 
and human element allocations) comply with 
their respective stakeholder expectations.
• A determination is made that the validated prod -
uct was appropriately integrated with the valida -
tion environment and the selected stakeholder 
expectations set was properly validated.
• A determination is made that the product being 
validated functions together with interfacing 
products throughout their operational envelopes.
5.4.1.2.3 Analyze Product Validation Results
Once the validation activities have been completed, 
the results are collected and the data are analyzed 
to confirm that the end product provided will sup -
ply the customer’s needed capabilities within the 
intended environments of use, validation procedures 
were followed, and enabling products and supporting 
resources functioned correctly. The data are also ana -
and validity, and any unsuitable products or product 
attributes are identified and reported.
It is important to compare the actual validation 
results to the expected results. If discrepancies are 
found, it needs to be determined if they are a result 
of the test configuration or analysis assumptions or 
whether they are a true characteristic or behavior of the end product. If it is found to be a result of the test 
configuration, the configuration should be corrected 
and the validation repeated. If it is found to be a result 
of the end product being validated, discussions with 
the customer should be held and any required sys -
tem design and product realization process activities 
should be conducted to resolve deficiencies. The defi -
ciencies along with recommended corrective actions 
and resolution results should be recorded, and valida -
tion should be repeated, as required.
Outcomes of analyzing validation results include the 
• Product anomalies, variations, deficiencies, non -
conformance and/or issues are identified.
• Assurances that appropriate replanning, redefi -
nition of requirements, design, and revalidation 
have been accomplished for resolution of anoma -
lies, variations, deficiencies or out-of-compliance 
conditions (for problems not caused by poor vali -
dation conduct).
• Discrepancy and corrective action reports are gen -
erated as needed.
• The validation report is completed.
Based on the results of the Product Validation Process, 
it could become necessary to re-engineer a deficient 
end product. Care should be taken that correcting a 
deficiency or set of deficiencies does not generate a 
new issue with a part or performance that had previ -
ously operated satisfactorily. Regression testing, a for -
mal process of rerunning previously used acceptance 
tests (primarily used for software), is one method to 
ensure a change does not affect function or perfor -
mance that was previously accepted.1045.0 Product Realization
Validation Deficiencies
Validation outcomes can be unsatisfactory for several 
reasons. One reason is poor conduct of the validation 
(e.g., enabling products and supporting resources 
missing or not functioning correctly, untrained 
operators, procedures not followed, equipment not 
calibrated, or improper validation environmental 
conditions) and failure to control other variables not 
involved in validating a set of stakeholder expecta -
tions. A second reason could be a shortfall in the ver -
ification process of the end product. This could create 
the need for:
• Re-engineering end products lower in the system 
structure that make up the end product that was 
found to be deficient (i.e., that failed to satisfy val -
idation requirements); and/or
• Re-performing any needed verification and vali -
dation processes.
Other reasons for validation deficiencies (particularly 
when M&S are involved) may be incorrect and/or 
inappropriate initial or boundary conditions; poor 
formulation of the modeled equations or behaviors; 
the impact of approximations within the modeled 
equations or behaviors; failure to provide the required 
geometric and physics fidelities needed for credible 
simulations for the intended purpose; and/or poor 
spatial, temporal, and perhaps, statistical resolution 
of physical phenomena used in M&S.
NOTE: Care should be exercised to ensure that 
the corrective actions identified to remove valida -
tion deficiencies do not conflict with the baselined 
stakeholder expectations without first coordinating 
such changes with the appropriate stakeholders.Of course, the ultimate reason for performing vali -
dation is to determine if the design itself is the right 
design for meeting stakeholder expectations. After 
any and all validation test deficiencies are ruled 
out, the true value of validation is to identify design 
changes needed to ensure the program/product’s 
mission. Validation should be performed as early and 
as iteratively as possible in the SE process since the 
earlier re-engineering needs are discovered, the less 
expensive they are to resolve.
Pass Verification but Fail Validation?
Sometimes systems successfully complete verification 
but then are unsuccessful in some critical phase of 
the validation process, delaying development and 
causing extensive rework and possible compromises 
with the stakeholder. Developing a solid ConOps in 
early phases of the project (and refining it through the 
requirements development and design phases) is crit -
ical to preventing unsuccessful validation. Similarly, 
developing clear expectations for user community 
involvement in the HSI Plan is critical to success -
ful validation. Frequent and iterative communica -
tions with stakeholders helps to identify operational 
scenarios and key needs that should be understood 
when designing and implementing the end product. 
Should the product fail validation, redesign may be a 
necessary reality. Review of the understood require -
ments set, the existing design, operational scenarios, 
user population numbers and skills, training, and 
support material may be necessary, as well as nego -
tiations and compromises with the customer, other 
stakeholders, and/or end users to determine what, if 
anything, can be done to correct or resolve the situ -
ation. This can add time and cost to the overall proj -
ect or, in some cases, cause the project to fail or be 
canceled. However, recall from FIGURE 2.5-1  that the 
earlier design issues are discovered, the less costly the 
corrective action.1055.0 Product Realization
5.4.1.2.4  Prepare Report and Capture Product 
Validation Work Products
Validation work products (inputs to the Technical 
and recording of validation-related data is a very 
important, but often underemphasized, step in the 
Validation results, deficiencies identified, and correc -
tive actions taken should be captured, as should all 
relevant results from the application of the Product 
Validation Process (related decisions, rationale for 
decisions made, assumptions, and lessons learned).
Outcomes of capturing validation work products 
• Work products and related information generated 
while doing Product Validation Process activities 
and tasks are recorded; i.e., method of validation 
conducted, the form of the end product used for 
validation, validation procedures used, validation 
environments, outcomes, decisions, assumptions, 
corrective actions, lessons learned, etc. (often cap -
tured in a matrix or other tool—see Appendix E ).
• Deficiencies (e.g., variations and anomalies and 
out-of-compliance conditions) are identified and 
documented, including the actions taken to resolve.
• Proof is provided that the end product is in con -
formance with the stakeholder expectation set 
used in the validation.
• Validation report including:
 »Recorded validation results/data;
 »Version of the set of stakeholder expectations 
used;
 »Version and form of the end product 
validated; »Version or standard for tools and equipment 
used, together with applicable calibration 
data;
 »Outcome of each validation including pass or 
 »Discrepancy between expected and actual 
results.
NOTE: For systems where only a single deliv -
erable item is developed, the Product Validation 
Process normally completes acceptance testing 
of the system. However, for systems with several

used;
data;
results.
of the system. However, for systems with several 
production units, it is important to understand 
that continuing verification and validation is not an 
appropriate approach to use for the items following 
the first deliverable. Instead, acceptance testing 
is the preferred means to ensure that subsequent 
deliverables meet stakeholder expectations.
5.4.1.3 Outputs
Key outputs of validation are:
• Validated end product:  This is the end product 
that has successfully passed validation and is 
ready to be transitioned to the next product layer 
or to the customer.
• Product validation results:  These are the raw 
results of performing the validations.
• Product validation report: This report provides 
the evidence of product conformance with the 
stakeholder expectations that were identified as 
being validated for the product at this layer. It 
includes any nonconformance, anomalies, or 
other corrective actions that were taken.
• Work products:  These include procedures, 
required personnel training, certifications, 1065.0 Product Realization
configuration drawings, and other records gener -
ated during the validation activities.
Success criteria for this process include: (1) objective 
evidence of performance and the results of each sys -
tem-of-interest validation activity are documented, 
and (2) the validation process should not be consid -
ered or designated as complete until all issues and 
actions are resolved.
5.4.2  Product Validation Guidance
Refer to Section 5.4.2 in the NASA Expanded 
• use of modeling and simulation,
• software validation, and
• taking credit for validation.
5.5 Product Transition
The Product Transition Process is used to transition a 
verified and validated end product that has been gen -
erated by product implementation or product inte -
gration to the customer at the next level in the system 
structure for integration into an end product or, for 
the top-level end product, transitioned to the intended 
end user. The form of the product transitioned will be 
a function of the product life cycle phase success cri -
teria and the location within the system structure of 
the WBS model in which the end product exists. The 
systems engineer involvement in this process includes 
ensuring the product being transitioned has been 
properly tested and verified/validated prior to being 
shipped to the next level stakeholder/customer.
Product transition occurs during all phases of the 
life cycle. During the early phases, the technical 
team’s products are documents, models, studies, and 
reports. As the project moves through the life cycle, these paper or soft products are transformed through 
implementation and integration processes into hard -
ware and software solutions to meet the stakeholder 
expectations. They are repeated with different degrees 
of rigor throughout the life cycle. The Product 
Transition Process includes product transitions from 
one level of the system architecture upward. The 
Product Transition Process is the last of the product 
realization processes, and it is a bridge from one level 
of the system to the next higher level.
The Product Transition Process is the key to bridge 
from one activity, subsystem, or element to the overall 
engineered system. As the system development nears 
completion, the Product Transition Process is again 
applied for the end product, but with much more 
rigor since now the transition objective is delivery of 
the system-level end product to the actual end user. 
Depending on the kind or category of system devel -
oped, this may involve a Center or the Agency and 
impact thousands of individuals storing, handling, 
and transporting multiple end products; preparing 
user sites; training operators and maintenance per -
sonnel; and installing and sustaining, as applicable. 
Examples are transitioning the external tank, solid 
rocket boosters, and orbiter to Kennedy Space Center 
(KSC) for integration and flight. Another example is 
the transition of a software subsystem for integration 
into a combined hardware/software system.
5.5.1  Process Description
FIGURE 5.5-1  provides a typical flow diagram for 
the Product Transition Process and identifies typical 
ing product transition.
5.5.1.1 Inputs
Inputs to the Product Transition Process depend pri -
marily on the transition requirements, the product 
that is being transitioned, the form of the product 1075.0 Product Realization
transition that is taking place, and the location to 
which the product is transitioning. Typical inputs are shown in 
FIGURE 5.5-1  and described below.To Product
Implementation,
Integration , Verification,
Validation , and 
Transition Processes    Product  Transition
Work ProductsEnd Product to Be
Transitioned 
Documentation to
Accomp any the
Deli vered End Product
Product Transition–
Management ProcessFrom Technical Data
Management Process  Deli vered  End Pro duct
With Applicable
Realized Enabling
Products  Prepare the end product for transition 
Prepare sites, as required, where the
end product will be stored, assembled,
integrated, installed, used, and/or
maintainedEvaluate the end product, personnel,
and enabling product readiness for
product transition 
transition activities  Prepare to conduct product
transition
Transition the end product to t he 
customer with required documentation
based on the type of transition requiredTo end user or Pro duct
Integration Process 
(recursive loop)
FIGURE 5.5-1  Pr oduct Transition Process
• The end product or products to be transitioned 
(from the Product Validation Process):  The prod -
uct to be transitioned can take several forms. It 
can be a subsystem component, system assembly, or top-level end product. It can be hardware, ana -
lytical models, or software. It can be newly built, purchased, or reused. A product can transition from a lower system product to a higher one by being integrated with other transitioned products. This process may be repeated until the final end product is achieved. Each succeeding transition requires unique input considerations when pre -
paring the validated product for transition to the next level.Early phase products can take the form of infor -
m
ation or data generated from basic or applied 
research using analytical or physical models and are often in paper or electronic form. In fact, the end product for many NASA research projects or science activities is a report, paper, model, or even an oral presentation. In a sense, the dissem -
ination of information gathered through NASA research and development is an important form of product transition.
• Documentation including manuals, procedures, 
and processes that accompany the end product (from the Technical Data Management
 Process):  
The documentation required for the Product 
Transition Process depends on the specific end product; its current location within the system 1085.0 Product Realization
structure; and the requirements identified in 
various agreements, plans, or requirements doc -
uments. Typically, a product has a unique iden -
tification (i.e., serial or version number) and may 
have a pedigree (documentation) that specifies its 
heritage and current state. Pertinent information 
may be controlled using a configuration control 
process or work order system as well as design 
drawings and test reports. Documentation often 
includes proof of verification and validation con -
formance. A COTS product would typically con -
tain a manufacturer’s specification or fact sheet. 
Documentation may include operations manuals, 
installation instructions, and other information.
The documentation level of detail is dependent 
upon where the product is within the product hier -
archy and the life cycle. Early in the life cycle, this 
documentation may be conceptual or preliminary 
in nature. Later in the life cycle, the documentation 
may be detailed design documents, user manuals, 
drawings, or other work products. Documentation 
that is gathered during the input process for the 
transition phase may require editing, assembling, 
or repackaging to ensure it is in the required condi -
tion for acceptance by the customer.
Special consideration should be given to safety, 
including clearly identifiable tags and markings 
that identify the use of hazardous materials, special 
handling instructions, and storage requirements.
• Product transition-enabling products, includ -
ing packaging materials; containers; handling 
equipment; and storage, receiving, and ship -
ping facilities (from existing resources or the 
Product Transition Process for enabling product 
realization): Product transition-enabling prod -
ucts may be required to facilitate the implementa -

tion, integration, evaluation, transition, training, 
operations, support, and/or retirement of the transition product at its next higher level or for 
the transition of the final end product. Some or all 
of the enabling products may be defined in tran -
sition-related agreements, system requirements 
documents, or project plans. In some cases, prod -
uct transition-enabling products are developed 
during the realization of the product itself or may 
be required to be developed during the transition 
stage.
As a product is developed, special containers, 
holders, or other devices may also be developed to 
aid in the storing and transporting of the product 
through development and realization. These may 
be temporary accommodations that do not sat -
isfy all the transition requirements, but allow the 
product to be initiated into the transition process. 
In such cases, the temporary accommodations 
will have to be modified or new accommodations 
will need to be designed and built or procured to 
meet specific transportation, handling, storage, 
and shipping requirements.
Sensitive or hazardous products may require spe -
cial enabling products such as monitoring equip -
ment, security features, inspection devices, safety 
devices, and personnel training to ensure ade -
quate safety and environmental requirements are 
achieved and maintained.
5.5.1.2 Process Activities
Transitioning the product can take one of two forms:
• The delivery of lower system end products to 
higher ones for integration into another end prod -
uct; or
• The delivery of the final end product to the cus -
tomer or user that will use it in its operational 
environment.1095.0 Product Realization
In the first case, the end product is one of perhaps 
several other pieces that will ultimately be integrated 
together to form the item. In the second case, the 
end product is for final delivery to the customer. For 
example, the end product might be one of several 
circuit cards that will be integrated together to form 
the final unit that is delivered. Or that unit might 
also be one of several units that have to be integrated 
together to form the final product.
The form of the product transitioned is not only a 
function of the location of that product within the 
system product hierarchy, but also a function of the 
life cycle phase. Early life cycle phase products may be 
in the form of paper, electronic files, physical models, 
or technology demonstration prototypes. Later phase 
products may be preproduction prototypes (engineer -
ing models), the final study report, or the flight units.
FIGURE 5.5-1  shows what kind of inputs, outputs, 
and activities are performed during product transi -
tion regardless of where in the product hierarchy or 
life cycle the product is. These activities include pre -
paring to conduct the transition; making sure the end 
product, all personnel, and any enabling products are 
ready for transitioning; preparing the site; and per -
forming the transition including capturing and doc -
umenting all work products.
How these activities are performed and what form the 
documentation takes depends on where the end items 
are in the product hierarchy and the life cycle phase.
5.5.1.2.1 Prepare to Conduct Transition
The first task is to identify which of the two forms 
of transition is needed: (1) the delivery of lower sys -
tem end products to higher ones for integration into 
another end product; or (2) the delivery of the final 
end product to the customer or user that will use the 
end product in its operational environment. The form 
of the product being transitioned affects transition planning and the kind of packaging, handling, stor -
age, and transportation that is required. The cus -
tomer and other stakeholder expectations, as well 
as the specific design solution, may indicate special 
transition procedures or enabling product needs for 
packaging, storage, handling, shipping/transporting, 
site preparation, installation, and/or sustainability. 
These requirements need to be reviewed during the 
preparation stage.
Other tasks in preparing to transition a product 
involve making sure the end product, personnel, and 
any enabling products are ready for that transition. 
This includes the availability of the documentation 
or models that will be sent with the end product, 
including proof of verification and validation confor -
mance. The appropriateness of detail for that docu -
mentation depends upon where the product is within 
the product hierarchy and the life cycle. Early in the 
life cycle, this documentation may be preliminary 
drawings, or other work products. Procedures neces -
sary for conducting the transition should be reviewed 
and approved by this time.
to conduct the transition as well as the availability 
of any necessary packaging materials/containers, 
handling equipment, storage facilities, and shipping/
transporter services should also be reviewed. Any 
form their tasks needs to be performed by this time.
5.5.1.2.2 Prepare the Site to Receive the Product
For either of the forms of product transition, the receiv -
ing site needs to be prepared to receive the product. 
Here the end product is stored, assembled, integrated, 
installed, used, and/or maintained as appropriate for 
the life cycle phase, position of the end product in the 
system structure, and customer agreement.1105.0 Product Realization
A vast number of key complex activities, many of 
them outside direct control of the technical team, 
need to be synchronized to ensure smooth transition 
to the end user. If transition activities are not care -
fully controlled, there can be impacts on schedule, 
cost, and safety of the end product.
A site survey may need to be performed to deter -
mine the issues and needs. This should address the 
adequacy of existing facilities to accept, store, and 
operate the new end product and identify any logis -
tical-support-enabling products and services required 
but not planned for. Additionally, any modifications 
to existing facilities should be planned well in advance 
of fielding; therefore, the site survey should be made 
during an early phase in the product life cycle. These 
may include logistical enabling products and ser -
vices to provide support for end-product use, opera -
tions, maintenance, and disposal. Training for users, 
operators, maintainers, and other support personnel 
may need to be conducted. National Environmental 
Policy Act documentation or approvals may need to 
be obtained prior to the receipt of the end product.
Prior to shipment or after receipt, the end product 
may need to be stored in suitable storage conditions 
to protect and secure the product and prevent dam -
age or the deterioration of it. These conditions should 
have been identified early in the design life cycle.
5.5.1.2.3 Prepare the Product for Transition
Whether transitioning a product to the next room for 
integration into the next higher assembly, or for final 
transportation across the country to the customer, 
care should be taken to ensure the safe transporta -
tion of the product. The requirements for packag -
ing, handling, storage, training, and transportation 
should have been identified during system design. 
Preparing the packaging for protection, security, and 
prevention of deterioration is critical for products 
placed in storage or when it is necessary to transport 
or ship between and within organizational facilities or between organizations by land, air, and/or water 
vehicles. Particular emphasis needs to be on protect -
ing surfaces from physical damage, preventing cor -
rosion, eliminating damage to electronic wiring or 
cabling, shock or stress damage, heat warping or cold 
fractures, moisture, and other particulate intrusion 
that could damage moving parts.
The design requirements should have already 
addressed the ease of handling or transporting the 
product such as component staking, addition of 
transportation hooks, crating, etc. The ease and 
safety of packing and unpacking the product should 
also have been addressed. Additional measures may 
also need to be implemented to show accountability 
and to securely track the product during transporta -
tion. In cases where hazardous materials are involved, 
special labeling or handling needs, including trans -
portation routes, need to be in place.
5.5.1.2.4 Transition the Product
The end product is then transitioned (i.e., moved, 
transported, or shipped) with required documen -
tation to the customer based on the type of tran -
sition required, e.g., to the next higher level item 
in the product hierarchy (often called the Product

in the product hierarchy (often called the Product 
Breakdown Structure (PBS)) for product integra -
tion or to the end user. Documentation may include 
operations manuals, installation instructions, and 
other information.
The end product is finally installed into the next 
higher assembly or into the customer/user site using 
the preapproved installation procedures.
Confirm Ready to Support
After installation, whether into the next higher 
assembly or into the final customer site, functional 
and acceptance testing of the end product should be 
conducted. This ensures no damage from the ship -
ping/handling process has occurred and that the 
product is ready for support. Any final transitional 1115.0 Product Realization
work products should be captured as well as docu -
mentation of product acceptance.
5.5.1.2.5 Capture Product Transition Work Products
Other work products generated during the transition 
process are captured and archived as appropriate. 
These may include site plans, special handling proce -
dures, training, certifications, videos, inspections, or 
other products from these activities.
5.5.1.3 Outputs
• Delivered end product with applicable docu -
mentation:  This may take one of two forms:
1. Delivered end product for integration to next 
level up in system structure: This includes the 
appropriate documentation. The form of the 
end product and applicable documentation 
are a function of the life cycle phase and the 
placement within the system structure. (The 
form of the end product could be hardware, 
software, model, prototype, first article for 
test, or single operational article or multiple 
production articles.) Documentation includes 
applicable draft installation, operation, user, 
maintenance, or training manuals; applicable 
baseline documents (configuration baseline, 
specifications, and stakeholder expectations); 
and test results that reflect completion of veri -
fication and validation of the end product.
2. Delivered operational end product for end 
users: The appropriate documentation is 
to accompany the delivered end product as 
well as the operational end product appro -
priately packaged. Documentation includes 
applicable final installation, operation, user, 
maintenance, or training manuals; applica -
ble baseline documents (configuration base -
line, specifications, stakeholder expectations); 
and test results that reflect completion of verification and validation of the end product. 
If the end user will perform end product val -
idation, sufficient documentation to support 
end user validation activities is delivered with 
the end  product.
• Work products from transition activities to tech -
nical data management:  Work products could 
include the transition plan, site surveys, measures, 
training modules, procedures, decisions, lessons 
learned, corrective actions, etc.
• Realized enabling end products to appropri -
ate life cycle support organization:  Some of the 
enabling products that were developed during the 
various phases could include fabrication or integra -
tion specialized machines; tools; jigs; fabrication 
processes and manuals; integration processes and 
manuals; specialized inspection, analysis, demon -
stration, or test equipment; tools; test stands; 
specialized packaging materials and containers; 
handling equipment; storage-site environments; 
shipping or transportation vehicles or equipment; 
specialized courseware; instructional site environ -
ments; and delivery of the training instruction. 
For the later life cycle phases, enabling products 
that are to be delivered may include specialized 
mission control equipment; data collection equip -
ment; data analysis equipment; operations man -
uals; specialized maintenance equipment, tools, 
manuals, and spare parts; specialized recovery 
equipment; disposal equipment; and readying 
recovery or disposal site environments.
• For deliveries to the integration path, the end 
product is delivered to intended usage sites in 
a condition suitable for integration with other 
end products or composites of end products. 1125.0 Product Realization
Procedures, decisions, assumptions, anomalies, 
corrective actions, lessons learned, etc., resulting 
from transition for integration are recorded.
• For delivery to the end user path, the end 
products are installed at the appropriate sites; 
appropriate acceptance and certification activi -
ties are completed; training of users, operators, 
maintainers, and other necessary personnel is 
completed; and delivery is closed out with appro -
priate acceptance documentation.• Any realized enabling end products are also deliv -
ered as appropriate including procedures, deci -
sions, assumptions, anomalies, corrective actions, 
lessons learned, etc., resulting from transition-en -
abling products.
5.5.2  Product Transition Guidance
Refer to Section 5.5.2 in the NASA Expanded 
• additional product transition considerations and
• what’s next after product transition to the end user.113
NASA SYSTEMS ENGINEERING HANDBOOK6.0Crosscutting Technical 
This chapter describes the activities in the techni -
cal management processes listed in the systems 
engineering engine ( FIGURE 2.1-1 ). The processes 
described in Chapters 4  and 5 are performed through 
the design and realization phases of a product. These 
processes can occur throughout the product life cycle, from concept through disposal. They may occur simultaneously with any of the other processes. The chapter is separated into sections corresponding to the technical management processes 10 through 17 listed in 
FIGURE 2.1-1 . Each technical management 
process is discussed in terms of the inputs, the activi -
ties, and the outputs. Additional guidance is provided 
The technical management processes are the bridges between project management and the technical team. In this portion of the engine, eight processes provide the crosscutting functions that allow the design solu -
tion to be developed, realized, and to operate. Even though every technical team member might not be directly involved with these eight processes, they are indirectly affected by these key functions. Every member of the technical team relies on technical planning; management of requirements, interfaces, technical risk, configuration, and technical data; technical assessment; and decision analysis to meet the project’s objectives. Without these crosscutting processes, individual members and tasks cannot be integrated into a functioning system that meets the ConOps within cost and schedule. These technical processes also support the project management team in executing project control.
The next sections describe each of the eight technical 
management processes and their associated products for a given NASA mission.
6.1 Technical Planning
The Technical Planning Process, the first of the eight technical management processes contained in the sys-tems engineering engine, establishes a plan for apply -
ing and managing each of the common technical processes that will be used to drive the development of system products and associated work products. This process also establishes a plan for identifying and defining the technical effort required to satisfy the project objectives and life cycle phase success cri -
teria within the cost, schedule, and risk constraints of the project.
This effort starts with the technical team conduct -
ing extensive planning early in Pre-Phase A. With 1146.0 Crosscutting Technical Management
this early planning, technical team members will 
understand the roles and responsibilities of each team member, and can establish cost and schedule goals and objectives. From this effort, the Systems Engineering Management Plan (SEMP) and other technical plans are developed and baselined. Once the SEMP and technical plans have been established, they should be synchronized with the project master plans and schedule. In addition, the plans for estab -
lishing and executing all technical contracting efforts are identified.CROSSCUTTING TECHNICAL MANAGEMENT KEYS
• Thoroughly understand and plan the scope of the technical effort by investing time upfront to develop the 
te
chnical product breakdown structure, the technical schedule and workflow diagrams, and the technical 
resource requirements and constraints (funding, budget, facilities, and long-lead items) that will be the technical planning infrastructure. The systems engineer also needs to be familiar with the non-technical aspects of the project.
•
 Defi
ne all interfaces and assign interface authorities and responsibilities to each, both intra-and inter-

te
•
 Defi
organizational. This includes understanding potential incompatibilities and defining the transition processes.
•
 Con
trol of the configuration is critical to understanding how changes will impact the system. For example, 
changes in design and environment could invalidate previous analysis results.
• Con
duct milestone reviews to enable a critical and valuable assessment to be performed. These reviews 
are not to be solely used to meet contractual or scheduling incentives. These reviews have specific entrance criteria and should be conducted when these are met.
•
 Unde
rstand any biases, assumptions, and constraints that impact the analysis results.
• Place
 all analysis under configuration control to be able to track the impact of changes and understand 
when the analysis needs to be reevaluated.
Th
is is a recursive and iterative process. Early in the 
life cycle, the technical plans are established and syn -
chronized to run the design and realization processes. 
As the system matures and progresses through the life cycle, these plans should be updated as neces -
sary to reflect the current environment and resources and to control the project’s performance, cost, and schedule. At a minimum, these updates will occur at e
very Key Decision Point (KDP). However, if there 
is a significant change in the project, such as new stakeholder expectations, resource adjustments, or other constraints, all plans should be analyzed for the impact of these changes on the baselined project.
6.1.1 Process Description
FIGURE 6.1-1  provides a typical flow diagram for the 
Technical Planning Process and identifies typical inputs, outputs, and activities to consider in address -
ing technical planning.
6.1.1.1  Inputs
Input to the Technical Planning Process comes from both the project management and technical teams as outputs from the other common technical processes. Initial planning utilizing external inputs from the project to determine the general scope and framework 1156.0 Crosscutting Technical Management
of the technical effort will be based on known tech -
nical and programmatic requirements, constraints, 
policies, and processes. Throughout the project’s life cycle, the technical team continually incorpo -
rates results into the technical planning strategy and documentation and any internal changes based on decisions and assessments generated by the other processes of the SE engine or from requirements and constraints mandated by the project.Project T ort
Requirements and P roject
Resource Constraints
Management ProcessFrom project 
From Technical Data
Management ProcessTo Technical
Assessment ProcessTo project 
To applicable technical
processes
To applicable technical teams
From Technical Assessment
and Technical Risk
Management ProcessesPrepare to conduct technical
planning
k 
Schedule, organize, and cost
the technical work 
Prepare SEMP and other
technical plans
Obtain stakeholder commitment s
to technical plans
Issue authorized technical
work direc tives
 technical planning activitiesAgreements, Capability
Needs, Applicable Product-
Line Life-Cycle Phase
Applicable Policies, 
Procedures, Standards, 
and Organizational 
Processes
Prior Phase or
Baseline Plans
Replanning NeedsCost Estimates,
Schedules, and Resource
Requests
Product and Process
Measures
SEMP and Other
Technical Plans
Technical Planning
Work P roductsTechnical Work Directives
FIGURE 6.1 -1 Tec hnical Planning Process
• Project Technical Effort Requirements and 
Project Resource Constraints:  The program/
project plan provides the project’s top-level tech -
nical requirements, the available budget allocated 
to the program/project from the program, and the desired schedule to support overall program needs. Although the budget and schedule allo -
ca
ted to the program/project serve as constraints, 
the technical team generates a technical cost estimate and schedule based on the actual work required to satisfy the technical requirements. Discrepancies between the allocated budget and schedule and the technical team’s actual cost esti -
mate and schedule should be reconciled continu -
ously throughout the life cycle.
• Agreements, Capability Needs, Applicable 
Product Life Cycle Phase:  The program/project 
plan also defines the applicable life cycle phases 
and milestones, as well as any internal and exter -
nal agreements or capability needs required for successful execution. The life cycle phases and 1166.0 Crosscutting Technical Management
programmatic milestones provide the general 
framework for establishing the technical plan -
ning effort and for generating the detailed tech -
nical activities and products required to meet the 
overall milestones in each of the life cycle phases.
• Applicable Policies, Procedures, Standards, 
and Organizational Processes:  The program/
project plan includes all programmatic policies, 
procedures, standards, and organizational pro -
cesses that should be adhered to during execution 
of the technical effort. The technical team should 
develop a technical approach that ensures the pro -
gram/project requirements are satisfied and that 
any technical procedures, processes, and stan -
dards to be used in developing the intermediate 
and final products comply with the policies and 
processes mandated in the program/project plan.
• Prior Phase or Baseline Plans:  The latest tech -
nical plans (either baselined or from the previous 
life cycle phase) from the Data Management or 
Configuration Management Processes should be 
used in updating the technical planning for the 
upcoming life cycle phase.
• Replanning Needs:  Technical planning updates 
may be required based on results from technical 
reviews conducted in the Technical Assessment 
Process, issues identified during the Technical 
Risk Management Process, or from decisions 
made during the Decision Analysis Process.
6.1.1.2 Process Activities
Technical planning as it relates to systems engineering 
at NASA is intended to define how the project will be 
organized, structured, and conducted and to identify, 
define, and plan how the 17 common technical pro -
cesses in NPR 7123.1, NASA Systems Engineering 
Processes and Requirements will be applied in each 
life cycle phase for all levels of the product hierarchy (see Section 6.1.2.1 in the NASA Expanded Guidance 
for Systems Engineering at https://nen.nasa.gov/web/
se/doc-repository .) within the system structure to 
meet product life cycle phase success criteria. A key 
document capturing and updating the details from 
the technical planning process is the SEMP.
The SEMP is a subordinate document to the proj -
ect plan. The project plan defines how the project 
will be managed to achieve its goals and objectives 
within defined programmatic constraints. The SEMP 
defines for all project participants how the project 
will be technically managed within the constraints 
established by the project. The SEMP also commu -
nicates how the systems engineering management 
techniques will be applied throughout all phases of 
the project life cycle.
Technical planning should be tightly integrated 
with the Technical Risk Management Process (see 
Section 6.4 ) and the Technical Assessment Process 
(see Section 6.7 ) to ensure corrective action for future 
activities will be incorporated based on current issues 
identified within the project.
Technical planning, as opposed to program or proj -
ect planning, addresses the scope of the technical 
effort required to develop the system products. While 
the project manager concentrates on managing the 
overall project life cycle, the technical team, led by 
the systems engineer, concentrates on managing the 
technical aspects of the project. The technical team 
identifies, defines, and develops plans for performing 
decomposition, definition, integration, verification, 
and validation of the system while orchestrating and 
incorporating the appropriate concurrent and cross -
cutting engineering. Additional planning includes 
defining and planning for the appropriate technical 
reviews, audits, assessments, and status reports and 
determining crosscutting engineering discipline and/
or design verification requirements.1176.0 Crosscutting Technical Management
This section describes how to perform the activities 
contained in the Technical Planning Process shown 
in FIGURE 6.1-1 . The initial technical planning at the 
beginning of the project establishes the technical 
team members; their roles and responsibilities; and 
the tools, processes, and resources that will be uti -
lized in executing the technical effort. In addition, 
the expected activities that the technical team will 
perform and the products it will produce are iden -
tified, defined, and scheduled. Technical planning 
continues to evolve as actual data from completed 
tasks are received and details of near-term and future 
activities are known.
6.1.1.2.1 T echnical Planning Preparation
For technical planning to be conducted properly, the 
processes and procedures that are needed to conduct 
technical planning should be identified, defined, 
and communicated. As participants are identified,

and communicated. As participants are identified, 
their roles and responsibilities and any training and/
or certification activities should be clearly defined 
and communicated.
Team Selection
Teams engaged in the early part of the technical 
planning process need to identify the required skill 
mix for technical teams that will develop and pro -
duce a product. Typically, a technical team consists 
of a mix of both subsystem and discipline engineers. 
Considering a spacecraft example, subsystem engi -
neers normally have cognizance over development of 
a particular subsystem (e.g., mechanical, power, etc.), 
whereas discipline engineers normally provide spe -
cific analyses (e.g., flight dynamics, radiation, etc.). 
The availability of appropriately skilled personnel 
also needs to be considered.
To an extent, determining the skill mix required 
for developing any particular product is a subjec -
tive process. Due to this, the skill mix is normally 
determined in consultation with people experienced in leading design teams for a particular mission or 
technical application. Some of the subjective consid -
erations involved include the product and its require -
ments, the mission class, and the project phase.
Continuing with a spacecraft example, most teams 
typically share a common core of required skills, such 
as subsystem engineering for mechanical, thermal, 
power, etc. However, the particular requirements of 
a spacecraft and mission can cause the skill mix to 
vary. For example, as opposed to robotic space mis -
sions, human-rated systems typically add the need 
for human systems discipline engineering and envi -
ronmental control and life support subsystem engi -
neering. As opposed to near Earth space missions, 
deep space missions may add the need for safety and 
planetary protection discipline engineering specific 
to contamination of the Earth or remote solar system 
bodies. And, as opposed to teams designing space -
craft instruments that operate at moderate tempera -
tures, teams designing spacecraft instruments that 
operate at cryogenic temperatures will need cryogen -
ics subsystem support.
Mission class and project phase may also influence the 
required team skill mix. For example, with respect to 
mission class, certain discipline analyses needed for 
Class A and B missions may not be required for Class 
D (or lower) missions. And with respect to project 
phase, some design and analyses may be performed by 
a single general discipline in Pre-Phase A and Phase 
A, whereas the need to conduct design and analyses 
in more detail in Phases B and C may indicate the 
need for multiple specialized subsystem design and 
discipline engineering skills.
An example skill mix for a Pre-Phase A technical 
team tasked to design a cryogenic interferometer 
space observatory is shown in TABLE 6.1-1  for pur -
poses of illustration. For simplicity, analysis and 
technology development is assumed to be included 1186.0 Crosscutting Technical Management
TABLE 6.1-1 Example Engineering Team Disciplines in Pre-Phase A for Robotic Infrared Observatory
Mission Systems Engineer
Instrument Systems Engineer
Spacecraft Bus, Flight Dynamics, Launch Vehicle Interface, Ground System Interface Subteam
Flight Dynamics Analysis
Mission Operations (includes ConOps, & interfaces with ground station, mission ops center, science ops center)
Bus Mechanical Subsystem (includes mechanisms)
Bus Power Subsystem (includes electrical harness)
Bus Thermal Subsystem
Bus Propulsion Subsystem
Bus Attitude Control and Determination Subsystem
Bus Avionics Subsystem
Bus Communications Subsystem
Bus Flight Software Subsystem
Integration and Test (bus, observatory)
Launch Vehicle Integration
Radiation Analysis
Orbital Debris/End of Mission Planning Analysis
System Reliability/Fault Tolerance Analysis (includes analysis of instrument)
Instrument Subteam
Mechanical Subsystem
Mechanisms Subsystem
Thermal Subsystem
Cryogenics Subsystem
Avionics Subsystem (incl. Electrical Harness)
Mechanism Drive Electronics Subsystem
Detector Subsystem
Optics Subsystem
Control Subsystem
Metrology Subsystem
Flight Software Subsystem
Integration and Test
Stray Light/Radiometry Analysis
Other Specialty Disciplines (e.g., Contamination Analysis) as needed1196.0 Crosscutting Technical Management
in the subsystem or discipline shown. For example, 
this means “mechanical subsystem” includes both 
loads and dynamics analysis and mechanical tech -
nology development.
Once the processes, people, and roles and responsi -
bilities are in place, a planning strategy may be for -
mulated for the technical effort. A basic technical 
planning strategy should address the following:
• The communication strategy within the technical 
team and for up and out communications;
• Identification and tailoring of NASA procedural 
requirements that apply to each level of the PBS 
structure;
• The level of planning documentation required 
for the SEMP and all other technical planning 
documents;
• Identifying and collecting input documentation;
• The sequence of technical work to be conducted, 
including inputs and outputs;
• The deliverable products from the technical work;
• How to capture the work products of technical 
activities;
• How technical risks will be identified and 
managed;
• The tools, methods, and training needed to con -
duct the technical effort;
• The involvement of stakeholders in each facet of 
• How the NASA technical team will be involved 
with the technical efforts of external contractors;
• The entry and success criteria for milestones, such 
as technical reviews and life cycle phases;
• The identification, definition, and control of 
internal and external interfaces;
• The identification and incorporation of relevant 
lessons learned into the technical planning;
• The team’s approach to capturing lessons learned 
during the project and how those lessons will be 
recorded;• The approach for technology development and 
how the resulting technology will be incorporated 
into the project;
• The identification and definition of the technical 
metrics for measuring and tracking progress to 
the realized product;
• The criteria for make, buy, or reuse decisions and 
incorporation criteria for Commercial Off-the-
Shelf (COTS) software and hardware;
• The plan to identify and mitigate off-nominal 
performance;
• The “how-tos” for contingency planning and 
replanning;
• The plan for status assessment and reporting;
• The approach to decision analysis, including 
materials needed, skills required, and expecta -
tions in terms of accuracy; and
• The plan for managing the human element in the 
technical activities and product.
By addressing these items and others unique to 
the project, the technical team will have a basis for 
understanding and defining the scope of the tech -
nical effort, including the deliverable products that 
the overall technical effort will produce, the schedule 
and key milestones for the project that the technical 
team should support, and the resources required by 
the technical team to perform the work.
A key element in defining the technical planning 
effort is understanding the amount of work associated 
with performing the identified activities. Once the 
scope of the technical effort begins to coalesce, the 
technical team may begin to define specific planning 
activities and to estimate the amount of effort and 
resources required to perform each task. Historically, 
many projects have underestimated the resources 
required to perform proper planning activities and 
have been forced into a position of continuous cri -
sis management in order to keep up with changes in 
the project.1206.0 Crosscutting Technical Management
Identifying Facilities
The planning process also includes identifying the 
required facilities, laboratories, test beds, and instru -
mentation needed to build, test, launch, and operate a variety of commercial and Government products. A sample list of the kinds of facilities that might be con -
sidered when planning is illustrated in 
TABLE 6.1-2 .
6.1.1.2.2  TABLE 6.1-2 Examples of Types of Facilities to Consider During Planning
Communications and Tracking Labs
Power Systems Labs
Propulsion Test Stands
Mechanical/Structures Labs
Instrumentation Labs
Human Systems Labs
Guidance and Navigation Labs
Robotics Labs
Software Development Environment
Meeting Rooms
Education/Outreach CentersModels and Simulation Labs
Prototype Development Shops
Calibration Labs
Biological Labs
Space Materials Curation Labs
Electromagnetic Effects Labs
Materials Labs
Vacuum Chambers
Mission Control Center
Training Facilities
Server FarmsThermal Chambers
Vibration Labs
Radiation Labs
Animal Care Labs
Flight Hardware Storage Areas
Design Visualization
Wiring Shops
NDE Labs
Logistics Warehouse
Conference Facilities
Project Documentation Centers
Define the T echnical Work

NDE Labs
The technical effort should be defined commensurate with the level of detail needed for the life cycle phase. When performing the technical planning, realistic values for cost, schedule, and labor resources should be used. Whether extrapolated from historical databases or from interactive planning sessions with the proj -
ect and stakeholders, realistic values should be calcu -
lated and provided to the project team. Contingency should be included in any estimate and should be based on the complexity and criticality of the effort. Contingency planning should be conducted. The fol -
lowing are examples of contingency planning:
• Additional, unplanned-for software engineering resources are typically needed during hardware and systems development and testing to aid in troubleshooting errors/anomalies. Frequently, s
oftware engineers are called upon to help trou -
bleshoot problems and pinpoint the source of errors in hardware and systems development and testing (e.g., for writing additional test drivers to debug hardware problems). Additional software staff should be planned into the project contin -
gencies to accommodate inevitable component and system debugging and avoid cost and sched -
ule overruns.
• Hardware-In-the-Loop (HWIL) should be accounted for in the technical planning contin -
gencies. HWIL testing is typically accomplished as a debugging exercise where the hardware and software are brought together for the first time in the costly environment of HWIL. If upfront work is not done to understand the messages and errors arising during this test, additional time in the HWIL facility may result in significant cost and schedule impacts. Impacts may be mitigated through upfront planning, such as making appro -
priate debugging software available to the techni -
cal team prior to the test, etc.1216.0 Crosscutting Technical Management
• Similarly, Human-In-The-Loop (HITL) evalua -
tions identify contingency operational issues. HITL 
investigations are particularly critical early in the 
design process to expose, identify, and cost-effec -
tively correct operational issues—nominal, main -
tenance, repair, off-nominal, training, etc.—in 
the required human interactions with the planned 
design. HITL testing should also be approached 
as a debugging exercise where hardware, software, 
and human elements interact and their perfor -
mance is evaluated. If operational design and/or 
performance issues are not identified early, the cost 
of late design changes will be significant.
6.1.1.2.3  Schedule, Organize, and Budget the T echnical 
Effort
Once the technical team has defined the technical 
work to be done, efforts can focus on producing a 
schedule and cost estimate for the technical portion 
of the project. The technical team should organize 
the technical tasks according to the project WBS 
in a logical sequence of events, taking into consid -
eration the major project milestones, phasing of 
available funding, and timing of the availability of 
supporting resources.
Scheduling
Products described in the WBS are the result of activ -
ities that take time to complete. These activities have 
time precedence relationships among them that may 
be used to create a network schedule explicitly defin -
ing the dependencies of each activity on other activ -
ities, the availability of resources, and the receipt of 
receivables from outside sources. Use of a scheduling 
tool may facilitate the development and maintenance 
of the schedule.
Scheduling is an essential component of planning 
and managing the activities of a project. The process 
of creating a network schedule provides a standard method for defining and communicating what needs 
to be done, how long it will take, and how each ele -
ment of the project WBS might affect other elements. 
A complete network schedule may be used to calcu -
late how long it will take to complete a project; which 
activities determine that duration (i.e., critical path 
activities); and how much spare time (i.e., float) exists 
for all the other activities of the project.
“Critical path” is the sequence of dependent tasks 
that determines the longest duration of time needed 
to complete the project. These tasks drive the schedule 
and continually change, so they should be updated. 
The critical path may encompass only one task or a 
series of interrelated tasks. It is important to identify 
the critical path and the resources needed to com -
plete the critical tasks along the path if the project is 
to be completed on time and within its resources. As 
the project progresses, the critical path will change as 
the critical tasks are completed or as other tasks are 
delayed. This evolving critical path with its identified 
tasks needs to be carefully monitored during the pro -
gression of the project.
Network scheduling systems help managers accu -
rately assess the impact of both technical and resource 
changes on the cost and schedule of a project. Cost 
and technical problems often show up first as sched -
ule problems. Understanding the project’s schedule 
is a prerequisite for determining an accurate project 
budget and for tracking performance and progress. 
Because network schedules show how each activity 
affects other activities, they assist in assessing and 
predicting the consequences of schedule slips or 
accelerations of an activity on the entire project.
For additional information on scheduling, refer to 
NASA/SP-2010-3403, NASA Schedule Management 
Handbook.1226.0 Crosscutting Technical Management
Budgeting
Budgeting and resource planning involve establish -
ing a reasonable project baseline budget and the capa -
bility to analyze changes to that baseline resulting 
from technical and/or schedule changes. The proj -
ect’s WBS, baseline schedule, and budget should be 
viewed as mutually dependent, reflecting the techni -
cal content, time, and cost of meeting the project’s 
goals and objectives. The budgeting process needs to 
take into account whether a fixed cost cap or fixed 
cost profile exists. When no such cap or profile exists, 
a baseline budget is developed from the WBS and 
network schedule. This specifically involves combin -
ing the project’s workforce and other resource needs 
with the appropriate workforce rates and other finan -
cial and programmatic factors to obtain cost element 
estimates. These elements of cost include
• direct labor costs,
• overhead costs,
• other direct costs (travel, data processing, etc.),
• subcontract costs,
• material costs,
• equipment costs,
• general and administrative costs,
• cost of money (i.e., interest payments, if 
applicable),
• fee (if applicable), and
• contingency (Unallocated Future Expenses (UFE)).
For additional information on cost estimating, refer 
to the NASA Cost Estimating Handbook and NPR 
7120.5, NASA Space Flight Program and Project 
Management Requirements .
6.1.1.2.4  Prepare the SEMP and Other T echnical Plans
Systems Engineering Management Plan
The SEMP is the primary, top-level technical man -
agement document for the project and is developed 
early in the Formulation Phase and updated through -
out the project life cycle. The SEMP is driven by the type of project, the phase in the project life cycle, and 
the technical development risks and is written specif -
ically for each project or project element. While the 
specific content of the SEMP is tailored to the project, 
the recommended content is discussed in Appendix J . 
It is important to remember that the main value of 
the SEMP is in the work that goes into the planning.
The technical team, working under the overall project 
plan, develops and updates the SEMP as necessary. 
The technical team works with the project manager 
to review the content and obtain concurrence. This 
allows for thorough discussion and coordination of 
how the proposed technical activities would impact 
the programmatic, cost, and schedule aspects of the 
project. The SEMP provides the specifics of the tech -
nical effort and describes the technical processes that 
will be used, how the processes will be applied using 
appropriate activities, how the project will be orga -
nized to accomplish the activities, and the cost and 
schedule associated with accomplishing the activities.
The physical length of a SEMP is not what is import -
ant. This will vary from project to project. The plan 
needs to be adequate to address the specific techni -
cal needs of the project. It is a living  document that 
is updated as often as necessary to incorporate new 
information as it becomes available and as the proj -
ect develops through the Implementation Phase. The 
SEMP should not duplicate other project documents; 
however, the SEMP should reference and summarize 
the content of other technical plans.
The systems engineer and project manager should 
identify additional required technical plans based on 
the project scope and type. If plans are not included 
in the SEMP, they should be referenced and coordi -
nated in the development of the SEMP. Other plans,

nated in the development of the SEMP. Other plans, 
such as system safety, probabilistic risk assessment, 
and an HSI Plan also need to be planned for and 
coordinated with the SEMP. If a technical plan is a 1236.0 Crosscutting Technical Management
stand-alone, it should be referenced in the SEMP. 
Depending on the size and complexity of the project, these may be separate plans or they may be included 
within the SEMP. Once identified, the plans can be 
developed, training on these plans established, and the plans implemented. Examples of technical plans in addition to the SEMP are listed in 
Appendix K .
The SEMP should be developed during pre- 
formulation. In developing the SEMP, the technical 
approach to the project’s life cycle is developed. This determines the project’s length and cost. The devel -
opment of the programmatic and technical man -
agement approaches requires that the key project personnel develop an understanding of the work to 
be performed and the relationships among the vari -
ous parts of that work. Refer to Sections 6.1.2.1 and 
6.1.1.2 on WBSs and network scheduling, respec-tively. The SEMP then flows into the project plan to ensure the proper allocation of resources including 
cost, schedule, and personnel.
The SEMP’s development requires contributions 
from knowledgeable programmatic and technical experts from all areas of the project that can signifi -
cantly influence the project’s outcome. The involve -
ment of recognized experts is needed to establish a SEMP that is credible to the project manager and to secure the full commitment of the project team.
Role of the SEMP
The SEMP is the rule book that describes to all par -
ticipants how the project will be technically man -
aged. The NASA technical team on the project 
should have a SEMP to describe how it will con -
duct its technical management, and each contractor 
should have a SEMP to describe how it will man -
age in accordance with both its contract and NASA’s technical management practices. Since the SEMP is unique to a project and contract, it should be 
updated for each significant programmatic change or it will become outmoded and unused and the proj -
ect could slide into an uncontrolled state. The lead 
NASA field Center should have its SEMP developed before attempting to prepare an initial cost estimate since activities that incur cost, such as technical risk reduction and human element accounting, need to be identified and described beforehand. The contractor 
should have its SEMP developed during the proposal 
process (prior to costing and pricing) because the SEMP describes the technical content of the project, the potentially costly risk management activities, and the verification and validation techniques to be used, 
all of which should be included in the preparation of 
project cost estimates. The SEMPs from the support -
ing Centers should be developed along with the pri -
mary project SEMP. The project SEMP is the senior technical management document for the project; all other technical plans should comply with it. The 
SEMP should be comprehensive and describe how a 
fully integrated engineering effort will be managed 
and conducted.
Verification Plan
The verification plan is developed as part of the Technical Planning Process and is baselined at PDR. As the design matures throughout the life cycle, the 
plan is updated and refined as needed. The task of 
preparing the verification plan includes establishing the method of verification to be performed, depen -
dent on the life cycle phase; the position of the prod -
uct in the system structure; the form of the product used; and the related costs of verification of individ -
ual specified requirements. The verification methods include analyses, inspection, demonstration, and test. In some cases, the complete verification of a given requirement might require more than one method. For example, to verify the performance of a product 
may require looking at many use cases. This might be 
accomplished by running a Monte Carlo simulation (analysis) and also running actual tests on a few of the key cases. The verification plan, typically written 1246.0 Crosscutting Technical Management
at a detailed technical level, plays a pivotal role in 
bottom-up product realization.
A phase product can be verified recursively through -
out the project life cycle and on a wide variety of 
product forms. For example:
TYPES OF HARDWARE
Breadboard:  A low fidelity unit that demonstrates function only without considering form or fit in the case 
of hardware or platform in the case of software. It often uses commercial and/or ad hoc components and is 
not intended to provide definitive information regarding operational performance.
Brassboard:  A medium fidelity functional unit that typically tries to make use of as much operational 
hardware/software as possible and begins to address scaling issues associated with the operational 
system. It does not have the engineering pedigree in all aspects, but is structured to be able to operate in simulated operational environments in order to assess performance of critical functions.
Engineering Unit:  A high fidelity unit that demonstrates critical aspects of the engineering processes 
involved in the development of the operational unit. Engineering test units are intended to closely resemble 
the final product (hardware/software) to the maximum extent possible and are built and tested so as to establish confidence that the design will function in the expected environments. In some cases, the engineering unit will become the final product, assuming proper traceability has been exercised over the components and hardware handling.
Prototype Unit: The prototype unit demonstrates form, fit, and function at a scale deemed to be 
representative of the final product operating in its operational environment. A subscale test article provides fidelity sufficient to permit validation of analytical models capable of predicting the behavior of full-scale systems in an operational environment.
Qualification Unit: A unit that is the same as the flight unit (form, fit, function, components, etc.) that will be 
exposed to the extremes of the environmental criteria (thermal, vibration, etc.). The unit will typically not be flown due to these off-nominal stresses.
Protoflight Unit:  In projects that will not develop a qualification unit, the flight unit may be designated as a 
protoflight unit and a limited version of qualification test ranges will be applied. This unit will be flown.Flight Unit:  The end product that will be flown and will typically undergo acceptance level testing.• simulated (algorithmic models, virtual reality 
simulator);
• mock-up (plywood, brassboard, breadboard);
• concept description (paper report);
• engineering unit (fully functional but may not be same form/fit);
• prototype (form, fit, and function);1256.0 Crosscutting Technical Management
• design verification test units (form, fit, and func -
tion is the same, but they may not have flight parts);
• qualification units (identical to flight units but 
may be subjected to extreme environments); and
• flight units (end product that is flown, including 
protoflight units).
Verification of the end product—that is, the official 
“run for the record” verification where the program/
project takes credit for meeting a requirement—is 
usually performed on a qualification, protoflight, or 
flight unit to ensure its applicability to the flight sys -
tem. However, with discussion and approval from the 
program/project and systems engineering teams, ver -
ification credit may be taken on lower fidelity units 
if they can be shown to be sufficiently like the flight 
units in the areas to be verified.
Any of these types of product forms may be in any of 
these states:
• produced (built, fabricated, manufactured, or coded);
• reused (modified internal non-developmental 
products or OTS product); or
• assembled and integrated (a composite of low -
er-level products).
The conditions and environment under which the 
product is to be verified should be established and 
the verification should be planned based on the asso -
ciated entrance/exit criteria that are identified. The 
Decision Analysis Process should be used to help 
finalize the planning details.
NOTE:  The final, official verification of the end 
product should be on a controlled unit. Typically, 
attempting to “buy off” a “shall” on a prototype is 
not acceptable; it is usually completed on a qualifi -
cation, flight, or other more final, controlled unit.Procedures should be prepared to conduct verifica -
tion based on the method (e.g., analysis, inspection, 
demonstration, or test) planned. These procedures 
are typically developed during the design phase 
of the project life cycle and matured as the design 
is matured. Operational use scenarios are thought 
through in order to explore all possible verification 
activities to be performed.

NOTE: Verification planning begins early in the 
project life cycle during the requirements devel -
opment phase. (See Section 4.2 .) The verification 
approach to use should be included as part of 
requirements development to plan for future activi -
ties, to establish special requirements derived from 
identified verification-enabling products, and to 
ensure that the requirements are verifiable. Updates 
to verification planning continue throughout logical 
decomposition and design development, especially 
as design reviews and simulations shed light on 
items under consideration. (See Section 6.1 .)
As appropriate, project risk items are updated based 
on approved verification strategies that cannot dupli -
cate fully integrated test systems, configurations, 
and/or target operating environments. Rationales, 
trade space, optimization results, and implications of 
the approaches are documented in the new or revised 
risk statements as well as references to accommodate 
future design, test, and operational changes to the 
project baseline.
Validation Plan
The validation plan is one of the work products of the 
Technical Planning Process and is generated during 
the Design Solution Process to validate the end prod -
uct against the baselined stakeholder expectations. 
This plan can take many forms. The plan describes 
the total Test and Evaluation (T&E) planning from 1266.0 Crosscutting Technical Management
development of lower-end through higher-end prod -
ucts in the system structure and through operational 
T&E into production and acceptance. It may com -
bine the verification and validation plans into a single 
document. (See Appendix I  for a sample Verification 
and Validation Plan outline.)
The methods of validation include test, demonstra -
tion, inspection, and analysis. While the name of 
each method is the same as the name of the methods 
for verification, the purpose and intent as described 
above are quite different.
Planning to conduct the product validation is a key 
first step. The method of validation to be used (e.g., 
analysis, demonstration, inspection, or test) should 
be established based on the form of the realized end 
product, the applicable life cycle phase, cost, sched -
ule, resources available, and location of the system 
product within the system structure.
An established set or subset of expectations or behav -
iors to be validated should be identified and the val -
idation plan reviewed (an output of the Technical 
Planning Process, based on design solution outputs) 
for any specific procedures, constraints, success cri -
teria, or other validation requirements. The condi -
tions and environment under which the product is 
to be validated should be established and the vali -
dation should be planned based on the relevant life 
cycle phase and associated success criteria identified. 
The Decision Analysis Process should be used to help 
It is important to review the validation plans with rel -
evant stakeholders and to understand the relationship 
between the context of the validation and the con -
text of use (human involvement). As part of the plan -
ning process, validation-enabling products should be 
identified and scheduling and/or acquisition should 
be initiated.Procedures should be prepared to conduct valida -
tion based on the method planned; e.g., analysis, 
inspection, demonstration, or test). These proce -
dures are typically developed during the design phase 
is matured. Operational and use-case scenarios are 
thought through in order to explore all possible vali -
dation activities to be performed.
Validation is conducted by the user/operator or by 
the developer as determined by NASA Center direc -
tives or the contract with the developers. Systems-
level validation (e.g., customer Test and Evaluation 
(T&E) and some other types of validation) may be 
performed by an acquirer testing organization. For 
those portions of validation performed by the devel -
oper, appropriate agreements should be negotiated 
to ensure that validation proof-of-documentation is 
delivered with the product.
Regardless of the source (buy, make, reuse, assemble 
and integrate) and the position in the system struc -
ture, all realized end products should be validated 
to demonstrate/confirm satisfaction of stakeholder 
expectations. Variations, anomalies, and out-of-com -
pliance conditions, where such have been detected, 
are documented along with the actions taken to 
resolve the discrepancies. Validation is typically car -
ried out in the intended operational environment or 
a relevant environment under simulated or actual 
operational conditions, not necessarily under the 
tightly controlled conditions usually employed for 
the Product Verification Process.
Validation of phase products can be performed recur -
sively throughout the project life cycle and on a wide 
variety of product forms. For example:
• simulated (algorithmic models, virtual reality 
• mock-up (plywood, brassboard, breadboard);1276.0 Crosscutting Technical Management
• engineering unit (functional but may not be same 
form/fit);
• prototype (product with form, fit, and function);
• design validation test units (form, fit, and func-tion may be the same, but they may not have flight parts);
• qualification unit (identical to flight unit but may be subjected to extreme environments); and
• flight unit (end product that is flown).
Any of these types of product forms may be in any of these states:
• reused (modified internal non-developmental products or off-the-shelf product); or
• assembled and integrated (a composite of lower level products).ENVIRONMENTS
Relevant Environment: Not all systems, subsystems, and/or components need to be operated in the 
operational environment in order to satisfactorily address performance margin requirements or stakeholder expectations. Consequently, the relevant environment is the specific subset of the operational environment that is required to demonstrate critical “at risk” aspects of the final product performance in an operational environment.
Operational Environment: The environment in which the final product will be operated. In the case of 
space flight hardware/software, it is space. In the case of ground-based or airborne systems that are not directed toward space flight, it is the environments defined by the scope of operations. For software, the environment is defined by the operational platform.
NO
TE: The final, official validation of the end 
product should be for a controlled unit. Typically, attempting final validation against the ConOps on a prototype is not acceptable: it is usually completed on a q
ualification, flight, or other more final, con -
trolled unit.
NOTE:  In planning for validation, consideration 
should be given to the extent to which validation testing will be done. In many instances, off-nominal operational scenarios and nominal operational sce -
narios should be utilized. Off-nominal testing offers insight into a system’s total performance charac -
teristics and often assists in identifying the design issues and human-machine interface, training, and procedural changes required to meet the mission goals and objectives. Off-nominal testing as well as nominal testing should be included when planning for validation.
For additional information on technical plans, refer 
to the following appendices of this document and to Section 6.1.1.2.4 of the NASA Expanded Guidance for Systems Engineering at 
se/doc-repository :1286.0 Crosscutting Technical Management
• Appendix H  Integration Plan Outline
• Appendix I   Verification and Validation Plan 
Outline
• Appendix J  SEMP Content Outline
• Appendix K  Technical Plans
• Appendix L   Interface Requirements Document 
Outline
• Appendix M  CM Plan Outline
• Appendix R  HSI Plan Content Outline
• Appendix S   Concept of Operations Annotated 
Outline
6.1.1.2.5  Obtain Stakeholder Commitments to 
T echnical Plans
Stakeholder Roles in Project Planning
To obtain commitments to the technical plans from 
the stakeholders, the technical team should ensure 
that the appropriate stakeholders, including subject 
domain experts, have a method to provide inputs and 
to review the project planning for implementation of 
stakeholder interests.
During the Formulation Phase, the roles of the stake -
holders should be defined in the project plan and the 
SEMP. Review of these plans and the agreements 
from the stakeholders to the content of these plans 
constitutes buy-in from the stakeholders to the techni -
cal approach. It is essential to identify the stakeholders 
and get their concurrence on the technical approach.

Outline
Outline
Later in the project life cycle, stakeholders may be 
responsible for delivering products to the project. 
Initial agreements regarding the responsibilities of 
the stakeholders are key to ensuring that the proj -
ect technical team obtains the appropriate deliveries 
from stakeholders.
Stakeholder Involvement in Defining Requirements
The identification of stakeholders is one of the early 
steps in the systems engineering process. As the proj -
ect progresses, stakeholder expectations are flowed down through the Logical Decomposition Process, 
and specific stakeholders are identified for all of the 
primary and derived requirements. A critical part 
of the stakeholders’ involvement is in the definition 
of the technical requirements. As requirements and 
the ConOps are developed, the stakeholders will be 
required to agree to these products. Inadequate stake -
holder involvement leads to inadequate requirements 
and a resultant product that does not meet the stake -
holder expectations. Status on relevant stakeholder 
involvement should be tracked and corrective action 
taken if stakeholders are not participating as planned.
Stakeholder Agreements
Throughout the project life cycle, communication 
with the stakeholders and commitments from the 
stakeholders may be accomplished through the use of 
agreements. Organizations may use an Internal Task 
Agreement (ITA), a Memorandum Of Understanding 
(MOU), or other similar documentation to establish 
the relationship between the project and the stake -
holder. These agreements are also used to document 
the customer and provider responsibilities for defin -
ing products to be delivered. These agreements should 
establish the Measures of Effectiveness (MOEs) or 
Measures of Performance (MOPs) that will be used 
to monitor the progress of activities. Reporting 
requirements and schedule requirements should be 
established in these agreements. Preparation of these 
agreements will ensure that the stakeholders’ roles 
and responsibilities support the project goals and that 
the project has a method to address risks and issues as 
they are identified.
Stakeholder Support for Forums
During development of the project plan and the 
SEMP, forums are established to facilitate communi -
cation and document decisions during the life cycle of 
the project. These forums include meetings, working 
groups, decision panels, and control boards. Each of 
these forums should establish a charter to define the 1296.0 Crosscutting Technical Management
scope and authority of the forum and identify neces -
sary voting or nonvoting participants. Ad hoc mem -
bers may be identified when the expertise or input of 
specific stakeholders is needed when specific topics 
are addressed. It is important to ensure that stake -
holders have been identified to support the forum.
6.1.1.2.6 Issue T echnical Work Directives
The technical team provides technical work directives 
to Cost Account Managers (CAMs). This enables the 
CAMs to prepare detailed plans that are mutually 
consistent and collectively address all of the work to 
be performed. These plans include the detailed sched -
ules and budgets for cost accounts that are needed for 
cost management and EVM.
Issuing technical work directives is an essential 
activity during Phase B of a project when a detailed 
planning baseline is required. If this activity is not 
implemented, then the CAMs are often left with 
insufficient guidance for detailed planning. The 
schedules and budgets that are needed for EVM will 
then be based on assumptions and local interpreta -
tions of project-level information. If this is the case, 
it is highly likely that substantial variances will occur 
between the baseline plan and the work performed. 
Providing technical work directives to CAMs pro -
duces a more organized technical team. This activity 
may be repeated when replanning occurs.
This “technical work directives” step produces: (1) 
planning directives to CAMs that result in (2) a con -
sistent set of cost account plans. Where EVM is called 
for, it produces (3) an EVM planning baseline, includ -
ing a Budgeted Cost of Work Scheduled (BCWS).
This activity is not limited to systems engineering. 
This is a normal part of project planning wherever 
there is a need for an accurate planning baseline. 
For additional information on Technical Work Directives, refer to Section 6.1.1.2.6 in the NASA 
6.1.1.2.7 Capture T echnical Planning Work Products
The work products from the Technical Planning 
Process should be managed using either the Technical 
Data Management Process or the Configuration 
Management Process as required. Some of the more 
important products of technical planning (i.e., the 
WBS, the SEMP, and the schedule, etc.) are kept 
under configuration control and captured using 
the CM process. The Technical Data Management 
Process is used to capture trade studies, cost estimates, 
technical analyses, reports, and other important 
documents not under formal configuration control. 
Work products, such as meeting minutes and corre -
spondence (including e-mail) containing decisions or 
agreements with stakeholders also should be retained 
and stored in project files for later reference.
6.1.1.3 Outputs
Typical outputs from technical planning activities are:
• Technical work cost estimates, schedules, and 
resource needs:  e.g., funds, workforce, facili -
ties, and equipment (to the project) within the 
project resources;
• Product and process measures:  Those needed 
to assess progress of the technical effort and 
the effectiveness of processes (to the Technical 
Assessment Process);
• SEMP and other technical plans:  Technical plan -
ning strategy, WBS, SEMP, HSI Plan, V&V Plan, 
and other technical plans that support implemen -
tation of the technical effort (to all processes; 
applicable plans to technical processes);1306.0 Crosscutting Technical Management
• Technical work directives: e.g., work packages or 
task orders with work authorization (to applicable 
technical teams); and
• Technical Planning Process work products: 
Includes products needed to provide reports, records, and non-deliverable outcomes of process activities (to the Technical Data Management Process).
The resulting technical planning strategy constitutes an outline, or rough draft, of the SEMP. This serves as a starting point for the overall Technical Planning Process after initial preparation is complete. When preparations for technical planning are complete, the technical team should have a cost estimate and sched -
ule for the technical planning effort. The budget and schedule to support the defined technical planning effort can then be negotiated with the project man -
ager to resolve any discrepancies between what is needed and what is available. The SEMP baseline needs to be completed. Planning for the update of the SEMP based on programmatic changes needs to be developed and implemented. The SEMP needs to be approved by the appropriate level of authority.
6.1.2  Technical Planning Guidance
Refer to Section 6.1.2 in the NASA Expanded Guidance for Systems Engineering at 
gov/web/se/doc-repository  for additional guidance on:• Work Breakdown Structure (WBS),
• cost definition and modeling, and
• lessons learned .
Additional information on the WBS can also be found in NASA/SP-2010-3404, NASA Work Breakdown Structure Handbook  and on costing in the 
NASA Cost Estimating Handbook.
DEFINITIONS
Traceability:  A discernible association between two or more logical entities such as requirements, system 
elements, verifications, or tasks.
Bidirectional traceability: The ability to trace any given requirement/expectation to its parent requirement/
expectation and to its allocated children requirements/expectations.6.2 Requirements Management
Requirements management activities apply to the 
management of all stakeholder expectations, cus -
tomer requirements, and technical product require -
ments down to the lowest level product component requirements (hereafter referred to as expectations and requirements). This includes physical functional and operational requirements, including those that result from interfaces between the systems in ques -
tion and other external entities and environments. The Requirements Management Process is used to:
• Identify, control, decompose, and allocate require -
ments across all levels of the WBS.
• Provide bidirectional traceability.1316.0 Crosscutting Technical Management
• Manage the changes to established requirement 
baselines over the life cycle of the system products.
6.2.1  Process Description
FIGURE 6.2-1  provides a typical flow diagram for the

FIGURE 6.2-1  provides a typical flow diagram for the 
Requirements Management Process and identifies typical inputs, outputs, and activities to consider in addressing requirements management.Expectations and 
Requirements to Be
ManagedFrom  system design processes 
From Product Verification
and Validation ProcessesTo Technical Data
Management ProcessTo Configuration
Management  ProcessPrepare to conduct
requirements management
Conduct requirements
management
Conduct expectations and 
requirements traceability
Manage ex pectations
and requirement changes
activitiesRequirements Change
Requests
TPM Estimation/
Evaluation ResultsRequirements
Documents
Approved Changes to
Requirements Baselines
Management Work
ProductsFrom project and Technical
Assessment P rocess
From Technical
Product Verification and
Product Validation Results 
FIGURE 6.2 -1 Re quirements Management Process
6.2.1.1  Inputs
There are several fundamental inputs to the Requirements Management Process.
• Expectations and requirements to be managed: 
Requirements and stakeholder expectations are identified during the system design processes, primarily from the Stakeholder Expectations Definition Process and the Technical Requirements Definition Process.• Requirement change requests: The Requirements 
Management Process should be prepared to deal with requirement change requests that can be generated at any time during the project life cycle or as a result of reviews and assessments as part of the Technical Assessment Process.
• TPM estimation/evaluation results: TPM esti -
mation/evaluation results from the Technical Assessment Process provide an early warning of the adequacy of a design in satisfying selected crit -
ical technical parameter requirements. Variances from expected values of product performance may trigger changes to requirements.
• Product verification and validation results: 
Product verification and product validation results from the Product Verification and Product Validation Processes are mapped into the 1326.0 Crosscutting Technical Management
requirements database with the goal of verifying 
and validating all requirements.
6.2.1.2 Process Activities
6.2.1.2.1  Prepare to Conduct Requirements 
Preparing to conduct requirements management 
includes gathering the requirements that were defined 
and baselined during the Requirements Definition 
Process. Identification of the sources/owners of each 
requirement should be checked for currency. The 
organization (e.g., change board) and procedures to 
perform requirements management are established.
6.2.1.2.2 Conduct Requirements Management
The Requirements Management Process involves 
managing all changes to expectations and require -
ments baselines over the life of the product and main -
taining bidirectional traceability between stakeholder 
expectations, customer requirements, technical prod -
uct requirements, product component requirements, 
design documents, and test plans and procedures. 
The successful management of requirements involves 
several key activities:
• Establish a plan for executing requirements 
management.
• Receive requirements from the system design pro -
cesses and organize them in a hierarchical tree 
structure.
• Maintain bidirectional traceability between 
• Evaluate all change requests to the requirements 
baseline over the life of the project and make 
changes if approved by change board.
• Maintain consistency between the require -
ments, the ConOps, and the architecture/design, and initiate corrective actions to eliminate 
inconsistencies.
6.2.1.2.3  Conduct Expectations and Requirements 
Traceability
As each requirement is documented, its bidirectional 
traceability should be recorded. Each requirement 
should be traced back to a parent/source requirement 
or expectation in a baselined document or identified 
as self-derived and concurrence on it sought from the 
next higher level requirements sources. Examples of 
self-derived requirements are requirements that are 
locally adopted as good practices or are the result 
of design decisions made while performing the 
activities of the Logical Decomposition and Design 
Solution  Processes.
The requirements should be evaluated, independently 
if possible, to ensure that the requirements trace is 
correct and that it fully addresses its parent require -
ments. If it does not, some other requirement(s) 
should complete fulfillment of the parent require -
ment and be included in the traceability matrix. In 
addition, ensure that all top-level parent document 
requirements have been allocated to the lower level 
requirements. If there is no parent for a particular 
requirement and it is not an acceptable self-derived 
requirement, it should be assumed either that the 
traceability process is flawed and should be redone 
or that the requirement is “gold plating” and should 
be eliminated. Duplication between levels should be 
resolved. If a requirement is simply repeated at a lower 
level and it is not an externally imposed constraint, 
it may not belong at the higher level. Requirements 
traceability is usually recorded in a requirements 
matrix or through the use of a requirements model -
ing application.1336.0 Crosscutting Technical Management
6.2.1.2.4  Managing Expectations and Requirement 
Changes
Throughout early Phase A, changes in requirements 
and constraints will occur as they are initially defined 
and matured. It is imperative that all changes be 
thoroughly evaluated to determine the impacts on 
the cost, schedule, architecture, design, interfaces, 
ConOps, and higher and lower level requirements. 
Performing functional and sensitivity analyses will 
ensure that the requirements are realistic and evenly 
allocated. Rigorous requirements verification and 
validation will ensure that the requirements can 
be satisfied and conform to mission objectives. All 
changes should be subjected to a review and approval 
cycle to maintain traceability and to ensure that the 
impacts are fully assessed for all parts of the system.
Once the requirements have been validated and 
reviewed in the System Requirements Review (SRR) 
in late Phase A, they are placed under formal con -
figuration control. Thereafter, any changes to the 
requirements should be approved by a Configuration 
Control Board (CCB) or equivalent authority. The 
systems engineer, project manager, and other key 
engineers usually participate in the CCB approval 
processes to assess the impact of the change including 
cost, performance, programmatic, and safety.
Requirement changes during Phases B and C are 
more likely to cause significant adverse impacts to 
the project cost and schedule. It is even more import -
ant that these late changes are carefully evaluated to 
fully understand their impact on cost, schedule, and 
technical designs.
The technical team should also ensure that the 
approved requirements are communicated in a timely 
manner to all relevant people. Each project should 
have already established the mechanism to track and 
disseminate the latest project information. Further 
information on Configuration Management (CM) 
can be found in Section 6.5 .6.2.1.2.5 Key Issues for Requirements Management
Requirements Changes
Effective management of requirements changes 
requires a process that assesses the impact of the pro -
posed changes prior to approval and implementation 
of the change. This is normally accomplished through 
the use of the Configuration Management Process. 
In order for CM to perform this function, a baseline 
configuration should be documented and tools used 
to assess impacts to the baseline. Typical tools used to 
analyze the change impacts are as follows:
• Performance Margins: This tool is a list of key 
performance margins for the system and the 
current status of the margin. For example, the 
propellant performance margin will provide the 
necessary propellant available versus the propel -
lant necessary to complete the mission. Changes 
should be assessed for their impact on perfor -
mance margins.
• CM Topic Evaluators List: This list is developed 
by the project office to ensure that the appropriate 
persons are evaluating the changes and provid -
ing impacts to the change. All changes need to 
be routed to the appropriate individuals to ensure 
that the change has had all impacts identified. 
This list will need to be updated periodically.
• Risk System and Threats List:  The risk system 
can be used to identify risks to the project and 
the cost, schedule, and technical aspects of the 
risk. Changes to the baseline can affect the con -
sequences and likelihood of identified risk or can 
introduce new risk to the project. A threats list 
is normally used to identify the costs associated 
with all the risks for the project. Project reserves 
are used to mitigate the appropriate risk. Analyses

are used to mitigate the appropriate risk. Analyses 
of the reserves available versus the needs identified 
by the threats list assist in the prioritization for 
reserve use.1346.0 Crosscutting Technical Management
The process for managing requirements changes needs 
to take into account the distribution of information 
related to the decisions made during the change pro -
cess. The Configuration Management Process needs 
to communicate the requirements change decisions to 
the affected organizations. During a board meeting to 
approve a change, actions to update documentation 
need to be included as part of the change package. 
These actions should be tracked to ensure that affected 
documentation is updated in a timely manner.
Requirements Creep
“Requirements creep” is the term used to describe 
the subtle way that requirements grow imperceptibly 
during the course of a project. The tendency for the 
set of requirements is to relentlessly increase in size 
during the course of development, resulting in a sys -
tem that is more expensive and complex than origi -
nally intended. Often the changes are quite innocent 
and what appear to be changes to a system are really 
enhancements in disguise.
However, some of the requirements creep involves 
truly new requirements that did not exist, and could 
not have been anticipated, during the Technical 
Requirements Definition Process. These new require -
ments are the result of evolution, and if we are to 
build a relevant system, we cannot ignore them.
There are several techniques for avoiding or at least 
minimizing requirements creep:
• The first line of defense is a good ConOps that has 
been thoroughly discussed and agreed-to by the 
customer and relevant stakeholders.
• In the early requirements definition phase, flush 
out the conscious, unconscious, and undreamed-of 
requirements that might otherwise not be stated.• Establish a strict process for assessing require -
ment changes as part of the Configuration 
Management Process.
• Establish official channels for submitting change 
requests. This will determine who has the author -
ity to generate requirement changes and submit 
them formally to the CCB (e.g., a contractor-des -
ignated representative, project technical leads, 
customer/science team lead, or user).
• Measure the functionality of each requirement 
change request and assess its impact on the rest of 
the system. Compare this impact with the conse -
quences of not approving the change. What is the 
risk if the change is not approved?
• Determine if the proposed change can be accom -
modated within the fiscal and technical resource 
budgets. If it cannot be accommodated within 
the established resource margins, then the change 
most likely should be denied.
6.2.1.2.6 Capture Work Products
These products include maintaining and reporting 
information on the rationale for and disposition and 
implementation of change actions, current require -
ment compliance status and expectation, and require -
ment baselines.
6.2.1.3 Outputs
Typical outputs from the requirements management 
activities are:
• Requirements Documents:  Requirements doc -
uments are submitted to the Configuration 
Management Process when the requirements are 
baselined. The official controlled versions of these 
documents are generally maintained in electronic 
format within the requirements management tool 1356.0 Crosscutting Technical Management
that has been selected by the project. In this way, 
they are linked to the requirements matrix with 
all of its traceable relationships.
• Approved Changes to the Requirements 
Baselines:  Approved changes to the require -
ments baselines are issued as an output of the 
Requirements Management Process after careful 
assessment of all the impacts of the requirements 
change across the entire product or system. A sin -
gle change can have a far-reaching ripple effect, 
which may result in several requirement changes 
in a number of documents.
• Various Requirements Management Work 
Products: Requirements management work prod -
ucts are any reports, records, and undeliverable out -
comes of the Requirements Management Process. 
For example, the bidirectional traceability status 
would be one of the work products that would be 
used in the verification and validation reports.
Guidance
Refer to Section 6.2.2 in the NASA Expanded 
• the Requirements Management Plan and
• requirements management tools.
6.3 Interface Management
The definition, management, and control of inter -
faces are crucial to successful programs or projects. 
Interface management is a process to assist in con -
trolling product development when efforts are divided 
among parties (e.g., Government, contractors, geo -
graphically diverse technical teams, etc.) and/or to 
define and maintain compliance among the products 
that should interoperate.The basic tasks that need to be established involve 
the management of internal and external interfaces 
of the various levels of products and operator tasks 
to support product integration. These basic tasks are 
as follows:
• Define interfaces;
• Identify the characteristics of the interfaces (phys -
ical, electrical, mechanical, human, etc.);
• Ensure interface compatibility at all defined inter -
faces by using a process documented and approved 
by the project;
• Strictly control all of the interface processes 
during design, construction, operation, etc.;
• Identify lower level products to be assembled and 
integrated (from the Product Transition Process);
• Identify assembly drawings or other documenta -
tion that show the complete configuration of the 
product being integrated, a parts list, and any 
assembly instructions (e.g., torque requirements 
for fasteners);
• Identify end-product, design-definition-specified 
requirements (specifications), and configuration 
documentation for the applicable work break -
down structure model, including interface spec -
ifications, in the form appropriate to satisfy the 
product life cycle phase success criteria (from the 
Configuration Management Process); and
• Identify product integration-enabling products 
(from existing resources or the Product Transition 
Process for enabling product realization).1366.0 Crosscutting Technical Management
6.3.1  Process Description
FIGURE 6.3-1  provides a typical flow diagram for the 
Interface Management Process and identifies typical 
ing interface management.From Project and
Technical Assessment
ProcessesFrom user or program and
system design processes 
Management Process 
Interface
Requirements Interface Con trol
Documents 
Approved Interface
Changes
Interface Management
Work ProductsPrepare or update interface
management procedures 
Conduc t interface management during
system design activities for each WBS-
like model in the system structure
Conduct  interface control Conduc t interface management during
product  integratio n activities  
Captu re wor k products from interface
management activities Interface
Changes 
FIGURE 6.3 -1 Int erface Management Process
6.3.1.1  Inputs
Typical inputs needed to understand and address interface management would include the following:
• Interface Requirements:  These include the inter -
nal and external functional, physical, and perfor -
mance interface requirements developed as part of the Technical Requirements Definition Process for the product(s).
• Interface Change Requests: These include 
changes resulting from program or project agree -
ments or changes on the part of the technical team as part of the Technical Assessment Process.Other inputs that might be useful are:
• System Description: This allows the design of 
the system to be explored and examined to deter -
mine where system interfaces exist. Contractor arrangements will also dictate where interfaces are needed.
• System Boundaries:  Documented physical 
boundaries, components, and/or subsystems, which are all drivers for determining where inter -
faces exist.
• Organizational Structure:  Decisions on which 
organization will dictate interfaces, particularly when there is the need to jointly agree on shared interface parameters of a system. The program and project WBS will also provide organizational interface boundaries.
• Boards Structure:  Defined board structure that 
identifies organizational interface responsibilities.1376.0 Crosscutting Technical Management
6.3.1.2 Process Activities
6.3.1.2.1  Prepare or Update Interface Management 
Procedures
These procedures establish the interface management 
responsibilities, what process will be used to main -
tain and control the internal and external functional

tain and control the internal and external functional 
and physical interfaces (including human), and how 
the change process will be conducted. Training of the 
technical teams or other support may also be required 
and planned.
6.3.1.2.2  Conduct Interface Management during 
System Design Activities
During project Formulation, the ConOps of the 
product is analyzed to identify both external and 
internal interfaces. This analysis will establish the 
origin, destination, stimuli, and special character -
istics of the interfaces that need to be documented 
and maintained. As the system structure and archi -
tecture emerges, interfaces will be added and existing 
interfaces will be changed and should be maintained. 
Thus, the Interface Management Process has a close 
relationship to other areas, such as requirements 
definition and configuration management, during 
this period.
6.3.1.2.3  Conduct Interface Management during 
During product integration, interface management 
activities would support the review of integration and 
assembly procedures to ensure interfaces are prop -
erly marked and compatible with specifications and 
interface control documents. The interface manage -
ment process has a close relationship to verification 
and validation. Interface control documentation and 
approved interface requirement changes are used as 
inputs to the Product Verification Process and the 
Product Validation Process, particularly where ver -
ification test constraints and interface parameters 
are needed to set the test objectives and test plans. Interface requirements verification is a critical aspect 
of the overall system verification.
6.3.1.2.4 Conduct Interface Control
Typically, an Interface Working Group (IWG) estab -
lishes communication links between those responsi -
ble for interfacing systems, end products, enabling 
products, and subsystems. The IWG has the respon -
sibility to ensure accomplishment of the planning, 
scheduling, and execution of all interface activities. 
An IWG is typically a technical team with appro -
priate technical membership from the interfacing 
parties (e.g., the project, the contractor, etc.). The 
IWG may work independently or as a part of a larger 
change control board.
6.3.1.2.5 Capture Work Products
Work products include the strategy and procedures 
for conducting interface management, rationale 
for interface decisions made, assumptions made in 
approving or denying an interface change, actions 
taken to correct identified interface anomalies, les -
sons learned and updated support and interface 
agreement documentation.
6.3.1.3 Outputs
Typical outputs needed to capture interface manage -
ment would include:
• Interface control documentation.  This is the 
documentation that identifies and captures the 
interface information and the approved inter -
face change requests. Types of interface docu -
mentation include the Interface Requirements 
Document (IRD), Interface Control Document/
Drawing (ICD), Interface Definition Document 
(IDD), and Interface Control Plan (ICP). These 
outputs will then be maintained and approved 
using the Configuration Management Process 
and become a part of the overall technical data 
package for the project.1386.0 Crosscutting Technical Management
• Approved interface requirement changes.  After 
the interface requirements have been baselined, 
the Requirements Management Process should 
be used to identify the need for changes, eval -
uate the impact of the proposed change, docu -
ment the final approval/disapproval, and update 
the requirements documentation/tool/database. 
For interfaces that require approval from all 
sides, unanimous approval is required. Changing 
interface requirements late in the design or 
implementation life cycle is more likely to have a 
significant impact on the cost, schedule, or tech -
nical design/operations.
• Other work products. These work products 
include the strategy and procedures for con -
ducting interface management, the rationale for 
interface decisions made, the assumption made 
in approving or denying an interface change, 
the actions taken to correct identified interface 
anomalies, the lessons learned in performing the 
interface management activities, and the updated 
support and interface agreement documentation.
6.3.2  Interface Management Guidance
Refer to Section 6.3.2 in the NASA Expanded 
• interface requirements documents,
• interface control documents,
• interface control drawings,
• interface definition documents,
• the interface control plans, and
• interface management tasks.6.4 Technical Risk Management
The Technical Risk Management Process is one of 
the crosscutting technical management processes. 
Risk is the potential for performance shortfalls, 
which may be realized in the future, with respect 
to achieving explicitly established and stated per -
formance requirements. The performance shortfalls 
may be related to institutional support for mission 
execution or related to any one or more of the follow -
ing mission execution domains:
• safety
• technical
• cost
• schedule
Systems engineers are involved in this process to help 
identify potential technical risks, develop mitigation 
plans, monitor progress of the technical effort to deter -
mine if new risks arise or old risks can be retired, and 
to be available to answer questions and resolve issues. 
The following is guidance in implementation of risk 
management in general. Thus, when implementing 
risk management on any given program/project, the 
responsible systems engineer should direct the effort 
accordingly. This may involve more or less rigor and 
formality than that specified in governing docu -
ments such as NPRs. Of course, if deviating from 
NPR “requirements,” the responsible engineer must 
follow the deviation approval process. The idea is to 
tailor the risk management process so that it meets 
the needs of the individual program/project being 
executed while working within the bounds of the 
governing documentation (e.g., NPRs). For detailed 
information on the Risk Management Process, refer 
to the NASA Risk Management Handbook (NASA/
SP-2011-3422) .1396.0 Crosscutting Technical Management
Risk is characterized by three basic components:
1. The scenario(s) leading to degraded performance 
with respect to one or more performance mea -
sures (e.g., scenarios leading to injury, fatality, destruction of key assets; scenarios leading to exceedance of mass limits; scenarios leading to cost overruns; scenarios leading to schedule slippage);
2. The likelihood(s) (qualitative or quantitative) of those scenario(s); and
3. The consequence(s) (qualitative or quantitative severity of the performance degradation) that would result if the scenario(s) was (were) to occur.Uncertainties are included in the evaluation of likeli -
hoods and consequences.
Scenarios begin with a set of initiating events that 
cause the activity to depart from its intended state. For each initiating event, other events that are rele -
vant to the evolution of the scenario may (or may not) occur and may have either a mitigating or exacerbat -
ing effect on the scenario progression. The frequen -
cies of scenarios with undesired consequences are determined. Finally, the multitude of such scenarios is put together, with an understanding of the uncer -
tainties, to create the risk profile of the system.
This “risk triplet” conceptualization of risk is illus-
trated in 
FIGURES 6.4-1  and 6.4-2 .Uncertainty AnalysisScenario Development 
Scenario 
ModelingConsequence
ModelingInitiating 
Event 
Selection1. What can go wrong?
    (definition of scenarios)2. How frequently does  it happen? (scenario frequency quantification)3. What are the  consequences? (scenario consequence  quantification)
Scenario 
Frequency
Evaluation
FIGURE 6.4-1  Ris k Scenario Development (Source: NASA/SP-2011-3421)
RISK =  Structure of ScenarioLikelihood and
Its UncertaintyConsequence Severity
and Its Uncertainty
Structure of ScenarioLikelihood and
FIGURE 6.4-2  Ris k as an Aggregate Set of Risk Triplets1406.0 Crosscutting Technical Management
Key Concepts in Risk Management  Risk: Risk is the potential for shortfalls, which may be realized in the 
future with respect to achieving explicitly-stated requirements. The performance shortfalls may be related to 
institutional support for mission execution, or related to any one or more of the following mission execution 
domains: safety, technical, cost, schedule. Risk is characterized as a set of triplets:
 >The scenario(s) leading to degraded performance in one or more performance measures.
 >The likelihood(s) of those scenarios.

 >The consequence(s), impact, or severity of the impact on performance that would result if those 
scenarios were to occur.
Uncertainties are included in the evaluation of likelihoods and consequences.
Cost Risk:  This is the risk associated with the ability of the program/project to achieve its life-cycle cost 
objectives and secure appropriate funding. Two risk areas bearing on cost are (1) the risk that the cost 
estimates and objectives are not accurate and reasonable; and (2) the risk that program execution will not 
meet the cost objectives as a result of a failure to handle cost, schedule, and performance risks.
Schedule Risk: Schedule risks are those associated with the adequacy of the time estimated and allocated 
for the development, production, implementation, and operation of the system. Two risk areas bearing on 
schedule risk are (1) the risk that the schedule estimates and objectives are not realistic and reasonable; and 
(2) the risk that program execution will fall short of the schedule objectives as a result of failure to handle 
cost, schedule, or performance risks.
Technical Risk: This is the risk associated with the evolution of the design and the production of the 
system of interest affecting the level of performance necessary to meet the stakeholder expectations and 
technical requirements. The design, test, and production processes (process risk) influence the technical 
risk and the nature of the product as depicted in the various levels of the PBS (product risk).
Programmatic Risk:  This is the risk associated with action or inaction from outside the project, over 
which the project manager has no control, but which may have significant impact on the project. These 
impacts may manifest themselves in terms of technical, cost, and/or schedule. This includes such activities 
as: International Traffic in Arms Regulations (ITAR), import/export control, partner agreements with other 
domestic or foreign organizations, congressional direction or earmarks, Office of Management and Budget 
(OMB) direction, industrial contractor restructuring, external organizational changes, etc.
Scenario:  A sequence of credible events that specifies the evolution of a system or process from a given 
state to a future state. In the context of risk management, scenarios are used to identify the ways in which a 
system or process in its current state can evolve to an undesirable state.1416.0 Crosscutting Technical Management
Undesired scenario(s) might come from technical or 
programmatic sources (e.g., a cost overrun, schedule slippage, safety mishap, health problem, malicious activities, environmental impact, or failure to achieve a needed scientific or technological objective or suc -
cess criterion). Both the likelihood and consequences may have associated uncertainties.
Description
FIGURE 6.4-3  provides a typical flow diagram for 
the Risk Management Process and identifies typical 
inputs, activities, and outputs to consider in address -
ing risk management.
Assessment and
Decision Analysis
Processes  From project and all
technical processes
To project and Technical
Data Management
Process 
Planning Process 
Technical Risk Status
Mea surements 
Technical Risk
Reporting
Requirements Technical Risk
IssuesTechnical Risk
Mitigation and/or
Contingency Actions 
Reports 
Work Products of
Management From project and
Process From project
Project Risk
Management Plan Prepare a strategy to conduct technical
risk management 
Identify technical risks
Prepare for technical risk mitigationConduct technical risk assessment
Monitor the status of each technical
risk periodically 
Implement technical risk mitigation and
contingency action plans as triggered 
Captur e wor k products from technical
risk management activities
FIGURE 6.4-3  Risk  Management Process6.4.1.1  Inputs
The following are typical inputs to risk management:• Project Risk Management Plan:  The Risk 
Management Plan is developed under the Technical Planning Process and defines how risk will be identified, mitigated, monitored, and con -
trolled within the project.
• Technical Risk Issues: These will be the techni -
cal issues identified as the project progresses that pose a risk to the successful accomplishment of the project mission/goals.
• Technical Risk Status Measurements: These 
are any measures that are established that help to monitor and report the status of project 
technical  risks.1426.0 Crosscutting Technical Management
• Technical Risk Reporting Requirements: 
Includes requirements of how technical risks will 
be reported, how often, and to whom.
Additional inputs that may be useful:
• Other Plans and Policies:  Systems Engineering 
Management Plan, form of technical data prod -
ucts, and policy input to metrics and thresholds.
• Technical Inputs: Stakeholder expectations, con -
cept of operations, imposed constraints, tracked 
observables, current program baseline, perfor -
mance requirements, and relevant experience data.
6.4.1.2 Activities
6.4.1.2.1  Prepare a Strategy to Conduct T echnical Risk 
This strategy would include documenting how the 
program/project risk management plan (as devel -
oped during the Technical Planning Process) will be 
implemented, identifying any additional technical 
risk sources and categories not captured in the plan, 
identifying what will trigger actions and how these 
activities will be communicated to the internal and 
external teams.
6.4.1.2.2 Identify T echnical Risks
On a continuing basis, the technical team will iden -
tify technical risks including their source, analyze 
the potential consequence and likelihood of the risks 
occurring, and prepare clear risk statements for entry 
into the program/project risk management system. 
Coordination with the relevant stakeholders for the 
identified risks is included. For more information on 
identifying technical risks, see Section 6.4.2.1.
6.4.1.2.3 Conduct T echnical Risk Assessment
Until recently, NASA’s Risk Management (RM) 
approach was based almost exclusively on Continuous 
Risk Management (CRM), which stresses the management of individual risk issues during imple -
mentation. In December of 2008, NASA revised its 
RM approach in order to more effectively foster pro -
active risk management. The new approach, which is 
outlined in NPR 8000.4, Agency Risk Management 
Procedural Requirements and further developed 
in NASA/SP-2011-3422, NASA Risk Management 
Handbook , evolves NASA‘s risk management to 
entail two complementary processes: Risk-Informed 
Decision Making (RIDM) and CRM. RIDM is 
intended to inform direction-setting systems engi -
neering (SE) decisions (e.g., design decisions) through 
better use of risk and uncertainty information in 
selecting alternatives and establishing baseline perfor -
mance requirements (for additional RIDM technical 
information, guidance, and process description, see 
NASA/SP-2010-576 Version 1, NASA Risk-Informed 
Decision Making Handbook ).
CRM is then used to manage risks over the course 
of the development and implementation phases of 
the life cycle to assure that requirements related to 
safety, technical, cost, and schedule are met. In the 
past, RM was considered equivalent to the CRM 
process; now, RM is defined as comprising both the 
RIDM and CRM processes, which work together to 
assure proactive risk management as NASA programs 
and projects are conceived, developed, and executed. 
FIGURE 6.4-4  illustrates the concept.
FIGURE 6.4-4 Risk Management as the Interaction of 
Risk-Informed Decision Making and Continuous Risk 
Management (Source: NASA/SP-2011-3422)1436.0 Crosscutting Technical Management
6.4.1.2.4 Prepare for T echnical Risk Mitigation
This includes selecting the risks that will be mitigated 
and more closely monitored, identifying the risk level 
or threshold that will trigger a risk mitigation action 
plan, and identifying for each risk which stakeholders 
will need to be informed that a mitigation/contin -
gency action is determined as well as which organi -
zations will need to become involved to perform the 
mitigation/contingency action.
6.4.1.2.5  Monitor the Status of Each T echnical Risk 
Periodically
Risk status will need to be monitored periodically at 
a frequency identified in the risk plan. Risks that are 
approaching the trigger thresholds will be monitored 
on a more frequent basis. Reports of the status are 
made to the appropriate program/project manage -
ment or board for communication and for decisions 
whether to trigger a mitigation action early. Risk sta -
tus will also be reported at most life cycle reviews.
6.4.1.2.6  Implement T echnical Risk Mitigation and 
Contingency Action Plans as Triggered
When the applicable thresholds are triggered, the

When the applicable thresholds are triggered, the 
technical risk mitigation and contingency action 
plans are implemented. This includes monitoring the 
results of the action plan implementation and mod -
ifying them as necessary, continuing the mitigation 
until the residual risk and/or consequence impacts 
are acceptable, and communicating the actions and 
results to the identified stakeholders. Action plan 
reports are prepared and results reported at appropri -
ate boards and at life cycle reviews.
6.4.1.2.7 Capture Work Products
Work products include the strategy and procedures for 
conducting technical risk management; the rationale 
for decisions made; assumptions made in prioritizing, 
handling, and reporting technical risks and action 
plan effectiveness; actions taken to correct action plan 
implementation anomalies; and lessons learned.6.4.1.3 Outputs
Following are key risk outputs from activities:
• Technical Risk Mitigation and/or Contingency 
Actions: Actions taken to mitigate identified risks 
or contingency actions taken in case risks are 
realized.
• Technical Risk Reports: Reports of the techni -
cal risk policies, status, remaining residual risks, 
actions taken, etc. Output at the agreed-to fre -
quency and recipients.
• Work Products: Includes the procedures for con -
ducting technical risk management; rationale for 
decisions made; selected decision alternatives; 
assumptions made in prioritizing, handling, and 
reporting technical risks; and lessons learned.
Guidance
For additional guidance on risk management, refer to 
NASA/SP-2010-576, NASA RIDM Handbook  and NASA/
SP-2011-3422, NASA Risk Management Handbook .
6.5 Configuration Management
Configuration management is a management disci -
pline applied over the product’s life cycle to provide 
visibility into and to control changes to perfor -
mance and functional and physical characteristics. 
Additionally, according to SAE Electronic Industries 
Alliance (EIA) 649B, improper configuration man -
agement may result in incorrect, ineffective, and/or 
unsafe products being released. Therefore, in order to 
protect and ensure the integrity of NASA products, 
NASA has endorsed the implementation of the five 
configuration management functions and the asso -
ciated 37 underlying principles defined within SAE/
EIA-649-2 Configuration Management Requirements 
for NASA Enterprises.1446.0 Crosscutting Technical Management
Together, these standards address what configuration 
management activities are to be done, when they are 
to happen in the product life cycle, and what plan -
ning and resources are required. Configuration man -
agement is a key systems engineering practice that, 
when properly implemented, provides visibility of a 
true representation of a product and attains the prod -
uct’s integrity by controlling the changes made to the 
baseline configuration and tracking such changes. 
Configuration management ensures that the con -
figuration of a product is known and reflected in 
product information, that any product change is ben -
eficial and is effected without adverse consequences, 
and that changes are managed.
CM reduces technical risks by ensuring correct prod -
uct configurations, distinguishes among product 
versions, ensures consistency between the product 
and information about the product, and avoids the 
embarrassment cost of stakeholder dissatisfaction and 
complaint. In general, NASA adopts the CM prin -
ciples as defined by SAE/EIA 649B, Configuration 
Management Standard , in addition to implementa -
tion as defined by NASA CM professionals and as 
approved by NASA management.
When applied to the design, fabrication/assembly, 
system/subsystem testing, integration, and opera -
tional and sustaining activities of complex technol -
ogy items, CM represents the “backbone” of the 
enterprise structure. It instills discipline and keeps 
the product attributes and documentation consistent. 
CM enables all stakeholders in the technical effort, at 
any given time in the life of a product, to use identical 
data for development activities and decision-making. 
CM principles are applied to keep the documentation 
consistent with the approved product, and to ensure 
that the product conforms to the functional and 
physical requirements of the approved design.6.5.1  Process Description
FIGURE 6.5-1  provides a typical flow diagram for the 
Configuration Management Process and identifies 
typical inputs, outputs, and activities to consider in 
addressing CM.
6.5.1.1 Inputs
The inputs for this process are:
• CM plan: This plan would have been developed 
under the Technical Planning Process and serves 
as the overall guidance for this process for the 
program/project
• Engineering change proposals:  These are the 
requests for changes to the established baselines 
in whatever form they may appear throughout the 
life cycle.
• Expectation, requirements and interface docu -
ments:  These baselined documents or models are 
key to the design and development of the product.
• Approved requirements baseline changes: The 
approved requests for changes will authorize the 
update of the associated baselined document or 
model.
• Designated configuration items to be controlled: 
As part of technical planning, a list or philosophy 
would have been developed that identifies the 
types of items that will need to be placed under 
configuration control.
6.5.1.2 Process Activities
There are five elements of CM (see FIGURE 6.5-2 ):
• configuration planning and management
• configuration identification,1456.0 Crosscutting Technical Management
• configuration change management,
• Configuration Status Accounting (CSA), and
• configuration verification.From project
From Requirements
 and Interface 
Management ProcessTo applicable
technical processes 
To project and
Technical Data
Management ProcessExpectation, 
Requirements, and
Interface Documents Engineering Change
ProposalsProject Configuration
Management Plan 
List of Configuration
Items Under
Control
Work Products Current
Baselines
Reports Approved
Baseline ChangesPrepare a strategy to conduct
configuration management
Identify baseline to be under
configuration control
Maintain the status of configuration Maintain the status of configuration 
documentation Manage configuration change control
Conduct configuration audits
Captur e work  products from
configuration management activities  
Identified Risk
to Be Contr olledDesignated
Configuration Items
to Be Contr olled
FIGURE 6.5 -1 Confi guration Management Process
6.5.1.2.1  Prepare a Strategy to Conduct CM
CM planning starts at a program’s or project’s incep -
tion. The CM office should carefully weigh the 
value of prioritizing resources into CM tools or into CM surveillance of the contractors. Reviews by the Ce
nter Configuration Management Organization 
(CMO) are warranted and will cost resources and time, but the correction of systemic CM problems before they erupt into losing configuration control are always preferable to explaining why incorrect or misidentified parts are causing major problems in the program/project.
VerificationConfiguration
Status
AccountingConfiguration
Change
ManagementConfiguration
Planning andConfiguration
IdentificationManagementCONFIG URATION
MANAGEMENT
FIGURE 6.5 -2 Five Elements of Configuration Management1466.0 Crosscutting Technical Management
One of the key inputs to preparing for CM imple -
mentation is a strategic plan for the project’s com -
plete CM process. This is typically contained in a 
CM plan. See Appendix M  for an outline of a typical 
CM plan.
This plan has both internal and external uses:
• Internal:  It is used within the program/project 
office to guide, monitor, and measure the over -
all CM process. It describes all the CM activities 
and the schedule for implementing those activities 
within the program/project.
• External:  The CM plan is used to communicate 
the CM process to the contractors involved in 
the program/project. It establishes consistent CM 
processes and working relationships.
The CM plan may be a standalone document or it 
may be combined with other program/project plan -
ning documents. It should describe the criteria for 
each technical baseline creation, technical approvals, 
and audits.
6.5.1.2.2  Identify Baseline to be Under Configuration 
Control
Configuration identification is the systematic process 
of selecting, organizing, and stating the product attri -
butes. Identification requires unique identifiers for a 
product and its configuration documentation. The 
CM activity associated with identification includes 
selecting the Configuration Items (CIs), determin -
ing the CIs’ associated configuration documentation, 
determining the appropriate change control author -

Control
ity, issuing unique identifiers for both CIs and CI 
documentation, releasing configuration documenta -
tion, and establishing configuration baselines.
NASA has four baselines, each of which defines a dis -
tinct phase in the evolution of a product design. The baseline identifies an agreed-to description of attri -
butes of a CI at a point in time and provides a known 
configuration to which changes are addressed. 
Baselines are established by agreeing to (and docu -
menting) the stated definition of a CI’s attributes. 
The approved “current” baseline defines the basis of 
the subsequent change. The system specification is 
typically finalized following the SRR. The functional 
baseline is established at the SDR and will usually 
transfer to NASA’s control at that time for contract -
ing efforts. For in-house efforts, the baseline is set/
controlled by the NASA program/project.
The four baselines (see FIGURE 6.5-3 ) normally con -
trolled by the program, project, or Center are the 
• Functional Baseline: The functional baseline 
is the approved configuration documentation 
that describes a system’s or top-level CI’s perfor -
mance requirements (functional, interoperability, 
and interface characteristics) and the verification 
required to demonstrate the achievement of those 
specified characteristics. The functional baseline 
is established at the SDR by the NASA program/
project. The program/project will direct through 
contractual agreements, how the functional base -
lines are managed at the different functional lev -
els. (Levels 1–4)
• Allocated Baseline:  The allocated baseline is 
the approved performance-oriented configura -
tion documentation for a CI to be developed 
that describes the functional, performance, and 
interface characteristics that are allocated from 
a higher level requirements document or a CI 
and the verification required to demonstrate 
achievement of those specified characteristics. 
The allocated baseline extends the top-level per -
formance requirements of the functional baseline 
to sufficient detail for defining the functional and 1476.0 Crosscutting Technical Management
performance characteristics and for initiating 
detailed design for a CI. The allocated baseline is usually controlled by the design organization until all design requirements have been verified. The allocated baseline is typically established at the successful completion of the PDR. Prior to CDR, NASA normally reviews design output for conformance to design requirements through incremental deliveries of engineering data. NASA control of the allocated baseline occurs through review of the engineering deliveries as data items.
• Product Baseline:  The product baseline is the 
approved technical documentation that describes Level 1 Technical
FUNCTIO NAL 
BASELINEConfiguration Information Non-Configuration 
Information (examples)Milestones
Major Architecture
Aspects of DesignComplete
ALLO CATED
BASELINE
Aspects of DesignComplete 
PROD UCT
BASELINE
Realization Aspects of 
Design Complete; Fabricationand Text Complete MDRConc ept
Partial analyses
and studies
Program and
project plans
Developmental
data 
 
Complete
analyses
data
Test plans 
 System Spec
 
Test information
Manuals
Certifications
Product 
structure  SDRSRR
PDR
ORRSARCDR
 Segment Spec
Prime Item
Design-to-Spec
End Item
End Item
Build-to-SpecEnd Item
Design-to-SpecEnd Item
Design-to-SpecSegment Spec Segment Spec
Prime Item
Design-to-SpecPrime Item
FIGURE 6.5 -3 Ev olution of Technical Baseline
the configuration of a CI during the production, 
fielding/deployment, and operational support phases of its life cycle. The established product baseline is controlled as described in the config -
uration management plan that was developed during Phase A. The product baseline is typically established at the completion of the CDR. The product baseline describes:
 »Detailed physical or form, fit, and function characteristics of a CI;
 »The selected functional characteristics desig -
nated for production acceptance testing; and
 »The production acceptance test requirements.1486.0 Crosscutting Technical Management
• As-Deployed Baseline: The as-deployed baseline 
occurs at the ORR. At this point, the design is consid -
ered to be functional and ready for flight. All changes 
will have been incorporated into the documentation.
6.5.1.2.3  Manage Configuration Change Control
Configuration change management is a process to manage approved designs and the implementation of approved changes. Configuration change man -
agement is achieved through the systematic proposal, justification, and evaluation of proposed changes followed by incorporation of approved changes and verification of implementation. Implementing con -
figuration change management in a given program/project requires unique knowledge of the program/project objectives and requirements. The first step establishes a robust and well-disciplined internal NASA Configuration Control Board (CCB) system, which is chaired by someone with program/project change authority. CCB members represent the stake -
holders with authority to commit the team they rep -
resent. The second step creates configuration change management surveillance of the contractor’s activity. The CM office advises the NASA program or project manager to achieve a balanced configuration change management implementation that suits the unique program/project situation. See 
FIGURE 6.5-4  for an 
example of a typical configuration change manage -
ment control process.
OriginatorNORMAL CONFIGURATION CHANGE PROCESS
CM Function ReviewersResponsible
Organization CCB Actionees
1.
• Prepare and
 submit change request
• Propose reviewers3. 4. 2.
5.• Receive and log 
 request in system
• Screen change
 package
• Release for reviewReview and 
submit comments
Schedule CCB and 
prepare agenda 
(if needed)
8b.Collect, track, 
and adjudicate
comments (with
reviewers and
originator)
6.
Prepare decision
package
9.7. 8a.
Complete
assigned actions• Disposition
 change request
• Assign action
 items as needed
• Release CCB minutes
• Track actions
10.
• Verify release
 package
• Release final
 documentation• Close change
 request• Execute approved  changes 
• Finalize
 documentation
FIGURE 6.5 -4 Ty pical Change Control Process1496.0 Crosscutting Technical Management
TYPES OF CONFIGURATION MANAGEMENT CHANGES
• Engineering Change: An engineering change is an iteration in the baseline. Changes can be major or 
minor. They may or may not include a specification change. Changes affecting an external interface must be coordinated and approved by all stakeholders affected.
> A “major” change is a change to the baseline configuration documentation that has significant impact (i.e., requires retrofit of delivered products or affects the baseline specification, cost, safety, compatibility with interfacing products, or operator, or maintenance training).
> A ”minor” change corrects or modifies configuration documentation or processes without impact to the interchangeability of products or system elements in the system structure.
• Wa
iver: A waiver is a documented agreement intentionally releasing a program or project from meeting a 
requirement. (Some Centers use deviations prior to Implementation and waivers during Implementation.) Authorized waivers do not constitute a change to a baseline.
6.5.1.2.4   Maintain the Status of Configuration 
Configuration Status Accounting (CSA) is the 
recording and reporting of configuration data nec -
essary to manage CIs effectively. An effective CSA system provides timely and accurate configuration information such as:
• Complete current and historical configuration documentation and unique identifiers.
• Status of proposed changes, deviations, and waiv -
ers from initiation to implementation.
• Status and final disposition of identified discrep -
ancies and actions identified during each config -
uration audit.
Some useful purposes of the CSA data include:
• An aid for proposed change evaluations, change decisions, investigations of design problems, war -
ranties, and shelf-life calculations• Historical traceability
• Software trouble reporting
• Performance measurement data
The following are critical functions or attributes to consider if designing or purchasing software to assist with the task of managing configuration.
• Ability to share data real time with internal and external stakeholders securely;
• Version control and comparison (track history of an object or product);
• Secure user checkout and check in;
• Tracking capabilities for gathering metrics (i.e., time, date, who, time in phases, etc.);
• Web based;
• Notification capability via e-mail;
• Integration with other databases or legacy systems;

• Compatible with required support contractors and/or suppliers (i.e., can accept data from a third party as required);
• Integration with drafting and modeling programs as required;1506.0 Crosscutting Technical Management
• Provide neutral format viewer for users;
• License agreement allows for multiple users within 
an agreed-to number;
• Workflow and life cycle management;
• Limited customization;
• Migration support for software upgrades;
• User friendly;
• Consideration for users with limited access;
• Ability to attach standard format files from 
desktop
• Workflow capability (i.e., route a CI as required 
based on a specific set of criteria); and
• Capable of acting as the one and only source for 
released information.
6.4.1.2.5 Conduct Configuration Audits
Configuration verification is accomplished by 
inspecting documents, products, and records; 
reviewing procedures, processes, and systems of 
operations to verify that the product has achieved its 
required performance requirements and functional 
attributes; and verifying that the product’s design is 
documented. This is sometimes divided into func -
tional and physical configuration audits. (See Section 
6.7.2.3 for more on technical reviews.)
6.4.1.2.6 Capture work Products
These include the strategy and procedures for config -
uration management, the list of identified configu -
ration items, descriptions of the configuration items, 
change requests, disposition of the requests, rational 
for dispositions, reports, and audit results.
6.5.1.3 Outputs
NPR 7120.5 defines a project’s life cycle in progressive 
phases. Beginning with Pre-Phase A, these steps in 
turn are grouped under the headings of Formulation 
and Implementation. Approval is required to transition between these phases. Key Decision Points 
(KDPs) define transitions between the phases. CM 
plays an important role in determining whether a 
KDP has been met. Major outputs of CM are:
• List of configuration items under control 
(Configuration Status Accounting (CSA) reports): 
This output is the list of all the items, documents, 
hardware, software, models, etc., that were iden -
tified as needing to be placed under configuration 
control. CSA reports are updated and maintained 
throughout the program and project life cycle.
• Current baselines: Baselines of the current configu -
rations of all items that are on the CM list are made 
available to all technical teams and stakeholders.
• CM reports: Periodic reports on the status of the 
CM items should be available to all stakeholders 
on an agreed-to frequency and at key life cycle 
reviews.
• Other CM work products: Other work products 
include the strategy and procedures used for CM; 
descriptions, drawings and/or models of the CM 
items; change requests and their disposition and 
accompanying rationale; reports; audit results as 
well as any corrective actions needed.
6.5.2  CM Guidance
Refer to Section 6.5.2 in the NASA Expanded 
• the impact of not doing CM,
• warning signs when you know you are in trouble, 
and
• when it is acceptable to use redline drawings.1516.0 Crosscutting Technical Management
6.6 Technical Data Management
The Technical Data Management Process is used 
to plan for, acquire, access, manage, protect, and use data of a technical nature to support the total life cycle of a system. Data Management (DM) includes the development, deployment, operations and support, eventual retirement, and retention of appropriate technical, to include mission and science, data beyond system retirement as required by NPR 1441.1, NASA Records Retention Schedules.
DM is illustrated in 
FIGURE 6.6-1 . Key aspects of DM 
for systems engineering include:
From all technical
processes and contractors To all technical processes
and  contractors 
To project and all
technical processes Technical Data
Mana ged 
Requests Technical Data
Electronic Exchange
Formats Form of Technical
Data Products 
Deli vered Technical
Data  Prepare for technical data
management implementation 
Collect and store required
technical data  
Provide technical data to authorize
Capture work products from technical
data management activitiesd
partiesMaintain stored technical data
FIGURE 6.6 -1 Te chnical Data Management Process• application of policies and procedures for data 
identification and control,
• timely and economical acquisition of technical data,
• assurance of the adequacy of data and its protection,
• facilitating access to and distribution of the data to the point of use,• analysis of data use,
• evaluation of data for future value to other pro -
grams/projects, and
• process access to information written in legacy software.
The Technical Data Management and Configuration Management Processes work side-by-side to ensure all information about the project is safe, known, and accessible. Changes to information under configu -
ration control require a Change Request (CR) and are typically approved by a Configuration Control Board. Changes to information under Technical Data Management do not need a CR but still need to be managed by identifying who can make changes to each type of technical data.
6.6.1  Process Description
FIGURE 6.6-1 provides a typical flow diagram for the 
Technical Data Management Process and identifies typical inputs, outputs, and activities to consider in addressing technical data management.1526.0 Crosscutting Technical Management
6.6.1.1 Inputs
• Technical data products to be managed: 
Technical data, regardless of the form or method 
of recording and whether the data are generated 
by the contractor or Government during the life 
cycle of the system being developed. (Electronic 
technical data should be stored with sufficient 
metadata to enable easy retrieval and sorting.)
• Technical data requests:  External or internal 
requests for any of the technical data generated by 
the program/project.
6.6.1.2 Process Activities
Each Center is responsible for policies and procedures 
for technical DM. NPR 7120.5 and NPR 7123.1 
define the need to manage data, but leave specifics to 
the individual Centers. However, NPR 7120.5 does 
require that DM planning be provided as either a 
section in the program/project plan, CM plan, or as 
a separate document. The program or project man -
ager is responsible for ensuring that the data required 
are captured and stored, data integrity is maintained, 
and data are disseminated as required.
Other NASA policies address the acquisition and 
storage of data and not just the technical data used in 
the life cycle of a system.
6.6.1.2.1  Prepare for T echnical Data Management 
The recommended procedure is that the DM plan be 
a separate plan apart from the program/project plan. 
DM issues are usually of sufficient magnitude to jus -
tify a separate plan. The plan should cover the follow -
ing major DM topics:
• Identification/definition/management of data sets.• Control procedures—receipt, modification, review, 
and approval.
• Guidance on how to access/search for data for users.
• Data exchange formats that promote data reuse 
and help to ensure that data can be used consis -
tently throughout the system, family of systems, 
or system of systems.
• Data rights and distribution limitations such as 
export-control Sensitive But Unclassified (SBU).
• Storage and maintenance of data, including mas -
ter lists where documents and records are main -
tained and managed.
Prepare a technical data management strategy. This 
strategy can document how the program/project data 
management plan will be implemented by the tech -
nical effort or, in the absence of such a program-level 
plan, be used as the basis for preparing a detailed 
technical data management plan, including:
• Items of data that will be managed according to 
program/project or organizational policy, agree -
ments, or legislation;
• The data content and format;
• A framework for data flow within the program/
project and to/from contractors including the lan -
guage(s) to be employed in technical effort infor -
mation exchanges;
• Technical data management responsibilities and 
authorities regarding the origin, generation, cap -
ture, archiving, security, privacy, and disposal of 
data products;1536.0 Crosscutting Technical Management
• Establishing the rights, obligations, and commit -
ments regarding the retention of, transmission of, 
and access to data items; and
• Relevant data storage, transformation, transmis -
sion, and presentation standards and conven -
tions to be used according to program/project or 
organizational policy, agreements, or legislative 
constraints.
• Obtain strategy/plan commitment from relevant 
stakeholders.

• Prepare procedures for implementing the techni -
cal data management strategy for the technical 
effort and/or for implementing the activities of 
the technical data management plan.
• Establish a technical database(s) to use for tech -
nical data maintenance and storage or work with 
the program/project staff to arrange use of the 
program/project database(s) for managing tech -
nical data.
• Establish data collection tools, as appropriate to 
the technical data management scope and avail -
able resources.
• Establish electronic data exchange interfaces in 
accordance with international standards/agree -
ments and applicable NASA standards.
Train appropriate stakeholders and other technical 
personnel in the established technical data manage -
ment strategy/plan, procedures, and data collection 
tools, as applicable
Data Identification/Definition
Each program/project determines data needs during 
the life cycle. Data types may be defined in standard 
documents. Center and Agency directives sometimes 
specify content of documents and are appropriately used for in-house data preparation. The standard 
description is modified to suit program/project-spe -
cific needs, and appropriate language is included 
in SOWs to implement actions resulting from the 
data evaluation. “Data suppliers” may be contrac -
tors, academia, or the Government. Procurement of 
data from an outside supplier is a formal procure -
ment action that requires a procurement document; 
in-house requirements may be handled using a less 
formal method. Below are the different types of data 
that might be utilized within a program/project:
• Data
 »“Data” is defined in general as “recorded 
information regardless of the form or method 
of recording.” However, the terms “data” and 
“information” are frequently used inter -
changeably. To be more precise, data gener -
ally should be processed in some manner to 
generate useful, actionable information.
 »“Data,” as used in SE DM, includes technical 
data; computer software documentation; and 
representation of facts, numbers, or data of 
any nature that can be communicated, stored, 
and processed to form information required 
by a contract or agreement to be delivered to, 
or accessed by, the Government.
 »Data include that associated with system 
development, modeling and simulation used 
in development or test, test and evaluation, 
installation, parts, spares, repairs, usage 
data required for product sustainability, and 
source and/or supplier data.
 »Data specifically not included in Technical 
Data Management would be data relating 
to general NASA workforce operations 
information, communications information 
(except where related to a specific require -
ment), financial transactions, personnel data, 1546.0 Crosscutting Technical Management
transactional data, and other data of a purely 
business nature.
• Data Call: Solicitation from Government stake -
holders (specifically Integrated Product Team 
(IPT) leads and functional managers) identi -
fies and justifies their data requirements from 
a proposed contracted procurement. Since 
data provided by contractors have a cost to the 
Government, a data call (or an equivalent activ -
ity) is a common control mechanism used to 
ensure that the requested data are truly needed. 
If approved by the data call, a description of each 
data item needed is then developed and placed 
on contract.
• Information:  Information is generally consid -
ered as processed data. The form of the processed 
data is dependent on the documentation, report, 
review formats, or templates that are applicable.
• Technical Data Package:  A technical data pack -
age is a technical description of an item adequate 
for supporting an acquisition strategy, produc -
tion, engineering, and logistics support. The 
package defines the required design configuration 
and procedures to ensure adequacy of item per -
formance. It consists of all applicable items such 
as drawings, associated lists, specifications, stan -
dards, performance requirements, quality assur -
ance provisions, and packaging details.
• Technical Data Management System:  The strat -
egies, plans, procedures, tools, people, data for -
mats, data exchange rules, databases, and other 
entities and descriptions required to manage the 
technical data of a program/project.
6.6.1.2.2 Collect and Store Data
Subsequent activities collect, store, and maintain 
technical data and provide it to authorized par -
ties as required. Some considerations that impact these activities for implementing Technical Data 
Management include:
• Requirements relating to the flow/delivery of data 
to or from a contractor should be specified in the 
technical data management plan and included in 
the Request for Proposal (RFP) and contractor 
agreement.
• NASA should not impose changes on existing 
contractor data management systems unless the 
program/project technical data management 
requirements, including data exchange require -
ments, cannot otherwise be met.
• Responsibility for data inputs into the technical 
data management system lies solely with the orig -
inator or generator of the data.
• The availability/access of technical data lies with 
the author, originator, or generator of the data in 
conjunction with the manager of the technical 
data management system.
• The established availability/access description and 
list should be baselined and placed under config -
uration control.
• For new programs/projects, a digital generation 
and delivery medium is desired. Existing pro -
grams/projects should weigh the cost/benefit 
trades of digitizing hard copy data.
TABLE 6.6-1  defines the tasks required to capture 
technical data.
6.6.1.2.3 Provide Data to Authorized Parties
All data deliverables should include distribution state -
ments and procedures to protect all data that contain 
critical technology information, as well as to ensure 
that limited distribution data, intellectual property 
data, or proprietary data are properly handled during 1556.0 Crosscutting Technical Management
systems engineering activities. This injunction applies 
whether the data are hard copy or digital.
As part of overall asset protection planning, NASA 
has established special procedures for the protection of Critical Program Information (CPI). CPI may include components; engineering, design, or manu -
facturing processes; technologies; system capabilities, and vulnerabilities; and any other information that gives a system its distinctive operational capability.
CPI protection should be a key consideration for the 
technical data management effort and is part of the asset protection planning process.
6.6.1.3  Outputs
Outputs include timely, secure availability of needed data in various representations to those authorized to receive it. Major outputs from the Technical Data Management Process include the following (see 
FIGURE 6.6-1 ):
• Form of Technical Data Products:  How each 
type of data is held and stored such as textual, graphic, video, etc.
• Technical Data Electronic Exchange Formats:  
Description and perhaps templates, models or other ways to capture the formats used for the var
ious data exchanges.
• Delivered Technical Data:  The data that were 
delivered to the requester.DATA COLLECTION CHECKLIST
• Have the frequency of collection and the points in the technical and technical management processes 
whe
n data inputs will be available been determined?
• Has th
e timeline that is required to move data from the point of origin to storage repositories or 
stakeholders been established?
• Who is r
esponsible for the input of the data?
• Who is r
esponsible for data storage, retrieval, and security?
• Have n
ecessary supporting tools been developed or acquired?
Oth
er work products generated as part of this process 
include the strategy and procedures used for techni -
cal data management, request dispositions, decisions, 
and assumptions.
Guidance
Refer to Section 6.6.2 in the NASA Expanded 
• data security and
• ITAR.
6.7 Technical Assessment
Technical assessment is the crosscutting process used to help monitor technical progress of a program/proj -
ect through periodic technical reviews and through monitoring of technical indicators such as MOEs, MOPs, Key Performance Parameters (KPPs), and TPMs. The reviews and metrics also provide status 1566.0 Crosscutting Technical Management
TABLE 6.6 -1 Technical Data Tasks
Description Tasks Expected Outcomes
Technical 
data captureCollect and store inputs and technical effort outcomes from the technical and technical management processes, including:
• results from technical assessments;
• descriptions of methods, tools, and metrics used;

Guidance
• ITAR.
Technical 
• recommendations, decisions, assumptions, and impacts of technical efforts and decisions;
• lessons learned;
• deviations from plan;
• anomalies and out-of-tolerances relative to requirements; and
• other data for tracking requirements.
Perform data integrity checks on collected data to ensure compliance with content and format as well as technical data checks to ensure there are no errors in specifying or recording the data.
Report integrity check anomalies or variances to the authors or generators of the data for 
correction.
Prioritize, review, and update data collection and storage procedures as part of regularly 
scheduled maintenance.Sharable data needed to perform and control the technical and technical management processes is collected and stored.
Stored data inventory.
Technical 
data maintenanceImplement technical management roles and responsibilities with technical data products received.
Manage database(s) to ensure that collected data have proper quality and integrity; and 
are properly retained, secure, and available to those with access authority.
Periodically review technical data management activities to ensure consistency and 
identify anomalies and variances.
Review stored data to ensure completeness, integrity, validity, availability, accuracy, 
currency, and traceability.
Perform technical data maintenance, as required.
Identify and document significant issues, their impacts, and changes made to technical 
data to correct issues and mitigate impacts.
Maintain, control, and prevent the stored data from being used inappropriately.Store data in a manner that enables easy and speedy retrieval.Maintain stored data in a manner that protects the technical data against foreseeable 
hazards, e.g., fire, flood, earthquake, etc.Records of technical data maintenance.
Technical effort data, 
including captured work 
products, contractor-delivered documents, and acquirer-provided documents are controlled and maintained.
Status of data stored is 
maintained to include: version description, timeline, and security classification.
Technical data/information distributionMaintain an information library or reference index to provide technical data availability and access instructions.
Receive and evaluate requests to determine data requirements and delivery instructions.Process special requests for technical effort data or information according to established 
procedures for handling such requests.
Ensure that required and requested data are appropriately distributed to satisfy the 
needs of the acquirer and requesters in accordance with the agreement, program/project 
directives, and technical data management plans and procedures.
Ensure that electronic access rules are followed before database access is allowed or any 
requested data are electronically released/transferred to the requester.
Provide proof of correctness, reliability, and security of technical data provided to internal 
and external recipients.Access information (e.g., available data, access means, security procedures, time period for availability, and personnel cleared for access) is readily available.
Technical data are provided 
to authorize requesters in the appropriate format, with the appropriate content, and by a secure mode of delivery, as applicable.
(continued)1576.0 Crosscutting Technical Management
Data 
management 
system 
maintenanceImplement safeguards to ensure protection of the technical database and of en route  
technical data from unauthorized access or intrusion.
Establish proof of coherence of the overall technical dataset to facilitate effective and 
efficient use.
Maintain, as applicable, backups of each technical database.
Evaluate the technical data management system to identify collection and storage 
performance issues and problems; satisfaction of data users; risks associated with 
delayed or corrupted data, unauthorized access, or survivability of information from 
hazards such as fire, flood, earthquake, etc.
Review systematically the technical data management system, including the database 
capacity, to determine its appropriateness for successive phases of the Defense 
Acquisition Framework.
Recommend improvements for discovered risks and problems:
Handle risks identified as part of technical risk management.
Control recommended changes through established program/project change management 
activities.Current technical data 
management system.
Technical data are 
appropriately and regularly 
backed up to prevent data 
loss.
information to support assessing system design, prod -
uct realization, and technical management decisions.
NASA has multiple review cycle processes for both 
space flight programs and projects (see NPR 7120.5), 
and research and technology programs and projects. 
(See NPR 7120.8, NASA Research and Technology 
Program and Project Management Requirements.) 
These different review cycles all support the same 
basic goals but with differing formats and formalities 
based on the particular program or project needs.
6.7.1 Process Description
FIGURE 6.7-1  provides a typical flow diagram for the 
Technical Assessment Process and identifies typical 
ing technical assessment. Technical assessment is 
focused on providing a periodic assessment of the 
program/project’s technical and programmatic sta -
tus and health at key points in the life cycle. There 
are 6 criteria considered in this assessment process: 
alignment with and contribution to Agency strategic 
goals; adequacy of management approach; adequacy 
of technical approach; adequacy of the integrated 
cost and schedule estimates and funding strategy; adequacy and availability of non-budgetary resources, 
and adequacy of the risk management approach.
6.7.1.1 Inputs
Typical inputs needed for the Technical Assessment 
Process would include the following:
• Technical Plans: These are the planning doc -
uments that will outline the technical reviews/
assessment process as well as identify the techni -
cal product/process measures that will be tracked 
and assessed to determine technical progress. 
Examples of these plans are the program (or 
project) plan, SEMP (if applicable), review plans 
(which may be part of the program or project 
plan), ILS plan, and EVM plan (if applicable). 
These plans contain the information and descrip -
tions of the program/project’s alignment with 
and contribution to Agency strategic goals, its 
management approach, its technical approach, its 
integrated cost and schedule, its budget, resource 
allocations, and its risk management approach.
• Technical Process and Product Measures: These 
are the identified technical measures that will be 1586.0 Crosscutting Technical Management
assessed or tracked to determine technical prog -
ress. These measures are also referred to as MOEs, 
MOPs, KPPs, and TPMs. (See Section 6.7.2.6.2 in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-re -
pository .) They provide indications of the program/
project’s performance in key management, techni -
cal, cost (budget), schedule, and risk areas.
• Reporting Requirements:  These are the require -
ments on the methodology in which the status of the technical measures will be reported with regard to management, technical cost (budget), sched -
ule, and risk. The requirements apply internally to the program/project and are used externally by the Centers and Mission Directorates to assess the performance of the program or project. The meth -
odology and tools used for reporting the status 
will be established on a project-by-project  basis.To Decision Analysis Process
Analysis Support 
Requests
Work Products from
Technical Assessment To Technical Data
Management Process To Technical Planning , 
Requirements , and  
Interface Management Processes  
Corrective Action
RecommendationsTechnical Cost and Schedule
Status Reports
Product Measurements
Decision Support
Recommendations and
Imp acts From Product Verification  and
Product Validation Processes 
From Decision Analysis Process Product and Process
Measures 
Technical PlansFrom Technical
Planning Process
From project
Risk Reporting
Technical Review
Reports To project and Technical Data
Management Process Assessment Results/
Findings To Technical Planning , 
Risk Management, and Requirements
Prepare strategy for conducting
technical assessments
Assess technical work product ivity 
(measure progress against plans)
Conduct horizontal and vertical progress
technical reviewsAssess technical produc t qua lity
(measure progress against requirements)
assessment activities
FIGURE 6.7 -1 Tech nical Assessment Process
6.7.1.2  Process Activities
6.7.1.2.1   Prepare Strategy for Conducting T echnical 
Assessments
As outlined in FIGURE 6.7-1 , the technical plans pro -

Measures 
vide the initial inputs into the Technical Assessment 
Process. These documents outline the technical reviews/assessment approach as well as identify the technical measures that will be tracked and assessed to determine technical progress. An important part of the technical planning is determining what is needed in time, resources, and performance to com -
plete a system that meets desired goals and objectives. Project managers need visibility into the progress of those plans in order to exercise proper management control. Typical activities in determining progress against the identified technical measures include sta -
tus reporting and assessing the data. Status report -
ing will identify where the project stands with regard to a particular technical measure. Assessing will 1596.0 Crosscutting Technical Management
analytically convert the output of the status report -
ing into a more useful form from which trends can 
be determined and variances from expected results 
can be understood. Results of the assessment activ -
ity then feed into the Decision Analysis Process (see 
Section 6.8 ) where potential corrective action may be 
necessary.
These activities together form the feedback loop 
depicted in FIGURE 6.7-2 .
(Re-)
PlanningStatus
ReportingAssessingDecision-
makingStatus Not OK
Status OKExecute
FIGURE 6.7 -2  Planning and Status  
Reporting Feedback Loop
This loop takes place on a continual basis throughout the project life cycle. This loop is applicable at each level of the project hierarchy. Planning data, status 
reporting data, and assessments flow up the hierar -
chy with appropriate aggregation at each level; deci -
sions cause actions to be taken down the hierarchy. 
Managers at each level determine (consistent with policies established at the next higher level of the project hierarchy) how often and in what form sta -
tus data should be reported and assessments should be made. In establishing these status reporting and assessment requirements, some principles of good practice are as follows:
• Use an agreed-upon set of well-defined technical measures. (See Section 6.7.2.6.2 in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-repository .)
• Report these technical measures in a consistent format at all project levels.• Maintain historical data for both trend identifica -
tion and cross-project analyses.
• Encourage a logical process of rolling up technical measures (e.g., use the WBS or PBS for project progress status).
• Support assessments with quantitative risk measures.
• Summarize the condition of the project by using color-coded (red, yellow, and green) alert zones for all technical measures.
6.7.1.2.2   Assess T echnical Work Productivity and Product 
Quality and Conduct Progress Reviews
Regular, periodic (e.g., monthly) tracking of the 
technical measures is recommended, although some measures should be tracked more often when there is 
rapid change or cause for concern. Key reviews, such 
as PDRs and CDRs, or status reviews are points at which technical measures and their trends should be carefully scrutinized for early warning signs of potential problems. Should there be indications that existing trends, if allowed to continue, will yield 
an unfavorable outcome, corrective action should 
begin as soon as practical. Section 6.7.2.6.1 in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-repository  pro-
vides additional information on status reporting and assessment techniques for costs and schedules 
(including EVM), technical performance, and sys -
tems engineering process metrics.
The measures are predominantly assessed during 
the program and project technical reviews. Typical activities performed for technical reviews include 
(1) identifying, planning, and conducting phase-to-
phase technical reviews; (2) establishing each review’s purpose, objective, and entry and success criteria; (3) 1606.0 Crosscutting Technical Management
establishing the makeup of the review team; and (4) 
identifying and resolving action items resulting from 
the review. Section 6.7.2.3 summarizes the types of 
technical reviews typically conducted on a program/
project and the role of these reviews in supporting 
management decision processes. This section address 
the types of technical reviews typically conducted 
for both space flight and research and technology 
programs/projects and the role of these reviews in 
supporting management decision processes. It also 
identifies some general principles for holding reviews, 
but leaves explicit direction for executing a review to 
the program/project team to define.
The process of executing technical assessment has 
close relationships to other areas, such as risk man -
agement, decision analysis, and technical planning. 
These areas may provide input into the Technical 
Assessment Process or be the benefactor of outputs 
from the process.
TABLE 6.7-1  provides a summary of the types of reviews 
for a space flight project, their purpose, and timing.
6.7.1.2.3 Capture Work Products
The work products generated during these activities 
should be captured along with key decisions made, 
supporting decision rationale and assumptions, 
and lessons learned in performing the Technical 
Assessment Process.
6.7.1.3 Outputs
Typical outputs of the Technical Assessment Process 
would include the following:
• Assessment Results, Findings, and 
Recommendations:  This is the collective data 
on the established measures from which trends 
can be determined and variances from expected 
results can be understood. Results then feed into 
the Decision Analysis Process where corrective 
action may be necessary.• Technical Review Reports/Minutes: This is the 
collective information coming out of each review 
that captures the results, recommendations, and 
actions with regard to meeting the review’s suc -
• Other Work Products:  These would include strat -
egies and procedures for technical assessment, key 
decisions and associated rationale, assumptions, 
and lessons learned.
6.7.2  Technical Assessment Guidance
Refer to Section 6.7.2 in the NASA Expanded 
nasa.gov/web/se/doc-repository  for additional guid -
ance on:
• the basis of technical reviews,
• audits,
• Key Decision Points,
• required technical reviews for space flight projects,
• other reviews,
• status reporting and assessment (including MOEs, 
MOPs, KPPs, TPMs, EVM and other metrics,
Additional information is also available in NASA/
SP-2014-3705, NASA Space Flight Program and 
Project Management Handbook.
6.8 Decision Analysis
The purpose of this section is to provide an over -
view of the Decision Analysis Process, highlighting 
selected tools and methodologies. Decision Analysis 
is a framework within which analyses of diverse types 
are applied to the formulation and characterization 
of decision alternatives that best implement the deci -
sion-maker’s priorities given the decision-maker’s 
state of knowledge.1616.0 Crosscutting Technical Management
TABLE 6.7-1  Purpose and Results for Life-Cycle Reviews for Spaceflight Projects
Name of 
ReviewPurpose Timing Entrance/Success CriteriaResults of Review
Mission Concept 
Review (MCR)The MCR will affirm the mission need and evaluates the proposed objectives and the concept for meeting those objectives.The MCR should be completed prior to entering the concept development phase (Phase A)The MCR entrance and success criteria are defined in Table G-3 of NPR 7123.1.A successful MCR supports the determination that the proposed mission meets the customer need and has sufficient quality and merit to support a field Center management decision to propose further study to the cognizant NASA program Associate Administrator as a candidate Phase A effort.
System Requirements Review (SRR)The SRR evaluates the functional and performance requirements defined for the system and the preliminary program or project plan and ensures that the requirements and selected concept will satisfy the mission.The SRR is conducted during the concept development phase (Phase A) and before conducting the SDR or MDR.The SRR entrance and success criteria for a program are defined in Table G-1 of NPR 7123.1. The SRR entrance and success criteria for projects and single-project programs are defined in Table G-4 of NPR 7123.1.Successful completion of the SRR freezes program/project requirements and leads to a formal decision by the cognizant program Associate Administrator to proceed with proposal request preparations for project implementation
Mission Definition 
Review (MDR)/  
System 
Definition Review (SDR)Sometimes called the MDR by robotic projects and SDR for 
human flight projects, this review

System 
human flight projects, this review 
evaluates whether the proposed architecture is responsive to the functional and performance requirements and that the requirements have been allocated to all functional elements of the mission/system.The MDR/SDR is conducted 
during the concept 
development phase (Phase A) prior to KDP B and the start of preliminary design.The MDR/SDR entrance and success criteria for 
a program are defined in 
Table G-2 of NPR 7123.1. The MDR/SDR entrance and success criteria for projects and single-project programs are defined in Table G-5 of NPR 7123.1.A successful MDR/SDR supports the decision to further develop the 
system architecture/design and any 
technology needed to accomplish the mission. The results reinforce the mission/system’s merit and provide a basis for the system acquisition strategy. As a result of successful completion, the mission/system and its operation are well enough understood to warrant design and acquisition of the end items.
Preliminary Design Review (PDR)The PDR demonstrates that the preliminary design meets all system requirements with 
acceptable risk and within the 
cost and schedule constraints and establishes the basis for proceeding with detailed design. It shows that the correct design options have been selected, interfaces have been identified, and verification methods have been described. The PDR should address and resolve critical, system-wide issues and show that work can begin on detailed design.PDR occurs near the completion of the preliminary 
design phase 
(Phase B) as the 
last review in the Formulation Phase.The entrance and success criteria for the PDR are defined in Table G-6 of NPR 7123.1.As a result of successful completion of the PDR, the design-to baseline is approved. A successful review result also authorizes the project to proceed into the Implementation Phase and toward final design.
(continued)1626.0 Crosscutting Technical Management
Name of 
Critical Design 
Review (CDR)The CDR demonstrates that the maturity of the design is appropriate to support proceeding with full scale fabrication, assembly, integration, and test. CDR determines if the technical effort is on track to complete the system development, 
meeting mission performance 
requirements within the identified cost and schedule constraints.CDR occurs during the final design phase (Phase C).The entrance and success criteria for the CDR are defined in Table G-7 of NPR 7123.1.As a result of successful completion of the CDR, the build-to baseline, production, and verification plans are approved. A successful review result also authorizes coding of deliverable software (according to the build-to baseline and coding standards presented in the review) and 
system qualification testing and 
integration. All open issues should be resolved with closure actions and schedules.
Production Readiness Review (PRR)A PRR is held for projects developing or acquiring multiple or similar systems greater than three or as determined by the project. The PRR determines the readiness of the system developers to efficiently produce the required number of systems. It ensures that the production plans; fabrication, assembly, and 
integration-enabling products; 
and personnel are in place and ready to begin production.PRR occurs during the final design phase (Phase C).The entrance and success criteria for the PRR are defined in Table G-8 of NPR 7123.1.As a result of successful completion of the PRR, the final production build-to baseline, production, and verification plans are approved. Approved drawings are released and authorized for production. A successful review result also authorizes coding of deliverable software (according to the build-to baseline and coding 
standards presented in the review) 
and system qualification testing and integration. All open issues should be resolved with closure actions and schedules.
System Integration Review (SIR)An SIR ensures segments, components, and subsystems are on schedule to be integrated into the system. Integration facilities, support personnel, and integration plans and procedures are on schedule to support integration.SIR occurs at the end of the final design phase (Phase C) and before the systems assembly, integration, and test phase (Phase D) begins.The entrance and success criteria for the SIR are defined in Table G-9 of NPR 7123.1.As a result of successful completion of the SIR, the final as-built baseline and verification plans are approved. Approved drawings are released and authorized to support integration. All open issues should be resolved with closure actions and schedules. The subsystems/systems 
integration procedures, ground 
support equipment, facilities, logistical needs, and support personnel are planned for and are ready to support integration.
System Acceptance Review (SAR)The SAR verifies the completeness of the specific end products in relation to their expected maturity level and assesses compliance to stakeholder expectations. It also ensures that the system has sufficient technical maturity to authorize its shipment to the 
designated operational facility or 
launch site.The entrance and success criteria for the SAR are defined in Table G-11 of 
NPR 7123.1.As a result of successful completion of the SAR, the system is accepted by the buyer, and authorization is given to ship the hardware to the launch site or operational facility and to install software and hardware for operational use.
(continued)1636.0 Crosscutting Technical Management
Name of 
Operational 
Readiness Review (ORR)The ORR examines the actual system characteristics and procedures used in the system or end product’s operation. It ensures that all system and support (flight and ground) hardware, software, personnel, procedures, and user documentation accurately reflect 
the deployed state of the system.The entrance and success 
criteria for the ORR are defined in Table G-12 of NPR 7123.1.As a result of successful ORR completion, the system is ready to assume normal operations.
Flight Readiness Review (FRR)The FRR examines tests, demonstrations, analyses, and audits that determine the system’s readiness for a safe and successful flight or launch and for subsequent flight operations. It also ensures that all flight and ground hardware, software, personnel, and procedures are operationally ready.The entrance and success criteria for the FRR are defined in Table G-13 of NPR 7123.1.As a result of successful FRR completion, technical and procedural maturity exists for system launch and flight authorization and, in some cases, initiation of system operations.
Post-Launch Assessment Review (PLAR)A PLAR is a post-deployment evaluation of the readiness of the spacecraft systems to proceed with full, routine operations. The review evaluates the status, performance, and capabilities of the project evident from the flight operations experience since launch. This can also mean assessing readiness to transfer responsibility from the development organization to the operations organization. The review also evaluates the status of the project plans and the capability to conduct the mission with emphasis on near-term operations and mission-critical events.This review is typically held after the early flight operations and initial checkout.The entrance and success criteria for the PLAR are defined in Table G-14 of NPR 7123.1.As a result of successful PLAR completion, the system is ready to assume in-space operations.
Critical Event Readiness Review (CERR)A CERR confirms the project’s readiness to execute the mission’s critical activities during flight operation. These include orbital insertion, rendezvous and docking, re-entry, scientific observations/encounters, etc.The CERR entrance and success criteria for a program are defined in Table G-15 of NPR 7123.1.As a result of successful CER completion, the system is ready to assume (or resume) in-space operations.
Post-Flight Assessment Review (PFAR)The PFAR evaluates the activities from the flight after recovery. The review identifies all anomalies that occurred during the flight and 
mission and determines the actions 
necessary to mitigate or resolve the anomalies for future flights.The entrance and success criteria for the PFAR are defined in Table G-16 of NPR 7123.1.As a result of successful PFAR completion, the report documenting flight performance and recommendations for future 
missions is complete and all 
anomalies have been documented and dispositioned.
(continued)1646.0 Crosscutting Technical Management
Name of 
Decommissioning

Name of 
Decommissioning 
Review (DR)The DR confirms the decision to terminate or decommission the system and assesses the readiness of the system for the safe decommissioning and disposal of system assets.The DR is normally held near the end of routine mission operations upon accomplishment of planned mission objectives. It may be advanced if some unplanned event gives rise to a need to prematurely terminate the mission, or delayed if operational life is extended to permit additional investigations.The entrance and success criteria for the DR are defined in Table G-17 of NPR 7123.1.A successful DR completion ensures that the decommissioning and disposal of system items and processes are appropriate and effective.
Disposal Readiness Review (DRR)A DRR confirms the readiness for the final disposal of the system assets.The DRR is held as major assets are ready for final disposal.The DRR entrance and success criteria for a program are defined in Table G-18 of NPR 7123.1.A successful DRR completion ensures that the disposal of system items and processes are appropriate and effective.
The Decision Analysis Process is used in support of 
decision making bodies to help evaluate technical, cost, and schedule issues, alternatives, and their uncertain -
ties. Decision models have the capacity for accepting and quantifying human subjective inputs: judgments of experts and preferences of decision makers.
The outputs from this process support the decision 
authority’s difficult task of deciding among compet -
ing alternatives without complete knowledge; there -
fore, it is critical to understand and document the assumptions and limitation of any tool or method -
ology and integrate them with other factors when deciding among viable options.
6.8.1  Process Description
A typical process flow diagram is provided in FIGURE 
6.8-1, including inputs, activities, and outputs. The 
first step in the process is understanding the deci -
sion to be made in the context of the system/mission. Understanding the decision needed requires knowl -
edge of the intended outcome in terms of technical performance, cost, and schedule. For an issue that follows the decision analysis process, the definition of the decision criteria or the measures that are import -
ant to characterize the options for making a decision should be the next step in the process. With this defined, a set of alternative solutions can be defined for evaluation. These solutions should cover the full decision space as defined by the understanding of the decision and definition of the decision criteria. The need for specific decision analysis tools (defined in Section 6.8.3 in the NASA Expanded Guidance for Systems Engineering at 
web/se/doc-repository ) can then be determined and 
employed to support the formulation of a solution. Following completion of the analysis, a description of how each alternative compares with the decision criteria can be captured for submission to the deci -
sion-making body or authority. A recommendation is typically provided from the decision analysis, but is not always required depending on the discretion of the decision-making body. A decision analysis report should be generated including: decision to be made, 1656.0 Crosscutting Technical Management
decision criteria, alternatives, evaluation methods, 
evaluation process and results, recommendation, and final decision.From all technical
processes 
Work Products From
Decision AnalysisTo Technical Data
Management Process Decision Need,
Alternatives, Issues, or 
Problems and
Supporting Data 
Decision Support  
ImpactsTo all technical processes
Alternative Selection
ImpactsFrom Technical
Assessment Process 
Analysis Support
RequestsEstablish guidelines to determine
which technical issues are subject to a
formal analysis/evaluation process
Identify alternative solutions to 
address decision issues
Select evaluation methods and toolsfor evaluating
alternative solutions
Evaluat e alternative solutions with 
the established criteria and
selected methods
Select recommended solutions from 
the alternatives based on the
evaluation criteria
Report analysis results with 
recommendations, impacts, and
corrective actions  
Captu re wor k products from 
decision analysis activities
FIGURE 6.8 -1 Deci sion Analysis Process
De
cision analysis covers a wide range of timeframes. 
Complex, strategic decisions may require weeks or months to fully assess all alternatives and potential outcomes. Decisions can also be made in hours or in a few days, especially for smaller projects or activi -
ties. Decisions are also made in emergency situations. Under such conditions, process steps, procedures, and meetings may be combined. In these cases, the focus of the systems engineer is on obtaining accurate deci -
sions quickly. Once the decision is made, the report can be generated. The report is usually generated in an ongoing fashion during the decision analysis pro -
ce
ss. However, for quick or emergency decisions, the 
report information may be captured after the deci -
sion has been made.
Not all decisions require the same amount of analysis 
effort. The level and rigor required in a specific situa -
tion depend essentially on how clear-cut the decision is. If there is enough uncertainty in the alternatives’ performance that the decision might change if that uncertainty were to be reduced, then consideration needs to be given to reducing that uncertainty. A robust decision is one that is based on sufficient tech -
nical evidence and characterization of uncertainties to determine that the selected alternative best reflects 1666.0 Crosscutting Technical Management
decision-maker preferences and values given the state 
of knowledge at the time of the decision. This is sug -
gested in FIGURE 6.8-2 .
Note that in FIGURE 6.8-2 , the phrase “net beneficial” 
in the decision node “Net beneficial to reduce uncer -
tainty?” is meant to imply consideration of all factors, including whether the project can afford any sched -
ule slip that might be caused by additional informa -
tion collection and additional analysis.Decision 
Alternatives for 
AnalysisExamples of Decisions
• Architecture A vs. Architecture V vs. Archicture C
• Extending the life of existing systems• Contingency Plan A vs. Contingency Plan B• Changing requirements• Launch or no launch• Making changes to existing systems•  Responding to operational occurrences in 
real time
• Technology A vs. Technology B• Prioritization
Preliminary Risk 
& Performance 
Measurement 
Results
NoYes
YesNo
Iteration
Additional Uncertainty Reduction Necessary per StakeholdersRisk Analysis 
Techniques
Spectrum 
of Available 
TechniquesQualitative 
Quantitative 
TechniquesRisk & 
Results
IdentifyAnalyzeDeliberation and 
Recommending a 
Decision Alternative
Is the ranking/
comparison robust?Scoping & 
Determination of 
Methods to  
Be Used
Net beneficial to 
reduce uncertainty?AnalyzeIdentify
FIGURE 6.8-2  Ris k Analysis of Decision Alternatives
6.8.1.1  Inputs
The technical, cost, and schedule inputs need to be 
comprehensively understood as part of the general decision definition. Based on this understanding, decision making can be addressed from a simple meeting to a formal analytical analysis. As illustrated in 
FIGURE 6.8-2 , many decisions do not require exten -
sive analysis and can be readily made with clear input from the responsible engineering and programmatic disciplines. Complex decisions may require more for -
mal decision analysis when contributing factors have complicated or not well defined relationships. Due to t
his complexity, formal decision analysis has the 
potential to consume significant resources and time. Typically, its application to a specific decision is war -
ranted only when some of the following conditions are met:
• Complexity:  The actual ramifications of alterna -
tives are difficult to understand without detailed analysis;
• Uncertainty: Uncertainty in key inputs creates 
substantial uncertainty in the ranking of alter -
natives and points to risks that may need to be managed;
• Multiple Attributes: Greater numbers of attributes 
cause a greater need for formal analysis; and
• Diversity of Stakeholders: Extra attention is war -
ranted to clarify objectives and formulate TPMs 1676.0 Crosscutting Technical Management
when the set of stakeholders reflects a diversity of 
values, preferences, and perspectives.
Satisfaction of all of these conditions is not a require -
ment for initiating decision analysis. The point is, 
rather, that the need for decision analysis increases 
as a function of the above conditions. In addition, 
often these decisions have the potential to result in 
high stakes impacts to cost, safety, or mission success 
criteria, which should be identified and addressed in 
the process. When the Decision Analysis Process is 
triggered, the following are inputs:
• Decision need, identified alternatives, issues, or 
problems and supporting data:  This information 
would come from all technical, cost, and sched -

ule management processes. It may also include 
high-level objectives and constraints (from the 
program/project).
• Analysis support requests:  Requests will arise 
from the technical, cost, and schedule assessment 
processes.
6.8.1.2 Process Activities
For the Decision Analysis Process, the following 
activities are typically performed.
It is important to understand the decision needed in 
the context of the mission and system, which requires 
knowledge of the intended outcome in terms of tech -
nical performance, cost, and schedule. A part of this 
understanding is the definition of the decision crite -
ria, or the measures that are important to character -
ize the options for making a decision. The specific 
decision-making body, whether the program/project 
manager, chief engineer, line management, or con -
trol board should also be well defined. Based on this 
understanding, then the specific approach to deci -
sion-making can be defined.Decisions are based on facts, qualitative and quan -
titative data, engineering judgment, and open com -
munications to facilitate the flow of information 
throughout the hierarchy of forums where technical 
analyses and evaluations are presented and assessed 
and where decisions are made. The extent of technical 
analysis and evaluation required should be commen -
surate with the consequences of the issue requiring 
a decision. The work required to conduct a formal 
evaluation is significant and applicability should be 
based on the nature of the problem to be resolved. 
Guidelines for use can be determined by the magni -
tude of the possible consequences of the decision to 
be made.
6.8.1.2.1  Define the Criteria for Evaluating Alternative 
Solutions
This step includes identifying the following:
• The types of criteria to consider, such as customer 
expectations and requirements, technology lim -
itations, environmental impact, safety, risks, total 
ownership and life cycle costs, and schedule impact;
• The acceptable range and scale of the criteria; and
• The rank of each criterion by its importance.
Decision criteria are requirements for individually 
assessing the options and alternatives being consid -
ered. Typical decision criteria include cost, sched -
ule, risk, safety, mission success, and supportability. 
However, considerations should also include tech -
nical criteria specific to the decision being made. 
Criteria should be objective and measurable. Criteria 
should also permit differentiating among options or 
alternatives. Some criteria may not be meaningful to 
a decision; however, they should be documented as 
having been considered. Criteria may be mandatory 
(i.e., “shall have”) or enhancing. An option that does 1686.0 Crosscutting Technical Management
not meet mandatory criteria should be disregarded. 
For complex decisions, criteria can be grouped into 
categories or objectives.
6.8.1.2.2  Identify Alternative Solutions to Address 
Decision Issues
With the decision need well understood, alterna -
tives can be identified that fit the mission and system 
context. There may be several alternatives that could 
potentially satisfy the decision criteria. Alternatives 
can be found from design options, operational 
options, cost options, and/or schedule options.
Almost every decision will have options to choose 
from. These options are often fairly clear within the 
mission and system context once the decision need is 
understood. In cases where the approach has uncer -
tainty, there are several methods to help generate 
various options. Brainstorming decision options with 
those knowledgeable of the context and decision can 
provide a good list of candidate alternatives. A litera -
ture search of related systems and approaches to iden -
tify options may also provide some possible options. 
All possible options should be considered. This can 
get unwieldy if a large number of variations is possi -
ble. A “trade tree” (discussed later) is an excellent way 
to prune the set of variations before extensive analysis 
is undertaken, and to convey to other stakeholders 
the basis for that pruning.
A good understanding of decision need and criteria 
will include the definition of primary and secondary 
factors. Options should be focused on primary fac -
tors in the decision as defined by the decision criteria. 
Non-primary factors (i.e., secondary, tertiary) can be 
included in evaluations but should not, in general, 
define separate alternatives. This will require some 
engineering judgment that is based on the mission 
and system context as well as the identified decision 
criteria. Some options may quickly drop out of con -
sideration as the analysis is conducted. It is important to document the fact that these options were consid -
ered. A few decisions might only have one option. It 
is a best practice to document a decision matrix for 
a major decision even if only one alternative is deter -
mined to be viable. (Sometimes doing nothing or not 
making a decision is an option.)
6.8.1.2.3 Select Evaluation Methods and Tools
Based on the decision to be made, various approaches 
can be taken to evaluate identified alternatives. These 
can range from simple discussion meetings with con -
tributing and affected stakeholders to more formal 
evaluation methods. In selecting the approach, the 
mission and system context should be kept in mind 
and the complexity of the decision analysis should 
fit the complexity of the mission, system, and corre -
sponding decision.
Evaluation methods and tools/techniques to be used 
should be selected based on the purpose for analyzing 
a decision and on the availability of the information 
used to support the method and/or tool. Typical eval -
uation methods include: simulations; weighted trade-
off matrices; engineering, manufacturing, cost, and 
technical opportunity trade studies; surveys; human-
in-the-loop testing; extrapolations based on field expe -
rience and prototypes; user review and comment; and 
testing. Section 6.8.2  provides several options.
6.8.1.2.4 Evaluate Alternative Solutions with the 
Established Criteria and Selected Methods
The performance of each alternative with respect to 
each chosen performance measure is evaluated. In all 
but the simplest cases, some consideration of uncer -
tainty is warranted. Uncertainty matters in a partic -
ular analysis only if there is a non-zero probability 
that uncertainty reduction could alter the ranking 
of alternatives. If this condition is obtained, then it 
is necessary to consider the value of reducing that 
uncertainty, and act accordingly.1696.0 Crosscutting Technical Management
Regardless of the methods or tools used, results 
should include the following:
• Evaluation of assumptions related to evaluation 
criteria and of the evidence that supports the 
assumptions; and
• Evaluation of whether uncertainty in the values 
for alternative solutions affects the evaluation.
When decision criteria have different measurement 
bases (e.g., numbers, money, weight, dates), normal -
ization can be used to establish a common base for 
mathematical operations. The process of “normaliza -
tion” is making a scale so that all different kinds of 
criteria can be compared or added together. This can 
be done informally (e.g., low, medium, high), on a 
scale (e.g., 1-3-9), or more formally with a tool. No 
matter how normalization is done, the most import -
ant thing to remember is to have operational defi -
nitions of the scale. An operational definition is a 
repeatable, measurable number. For example, “high” 
could mean “a probability of 67 percent and above.” 
“Low” could mean “a probability of 33 percent and 
below.” For complex decisions, decision tools usually 
provide an automated way to normalize. It is import -
ant to question and understand the operational defi -
nitions for the weights and scales of the tool.
NOTE: Completing the decision matrix can 
be thought of as a default evaluation method. 
Completing the decision matrix is iterative. Each 
cell for each criterion and each option needs to be 
completed by the team. Use evaluation methods as 
needed to complete the entire decision matrix.6.8.1.2.5  Select Recommended Solutions from the 
Alternatives Based on the Evaluation Criteria 
and Report to the Decision-Maker
Once the decision alternative evaluation is completed, 
recommendations should be brought back to the deci -
sion maker including an assessment of the robustness 
of the ranking (i.e., whether the uncertainties are such 
that reducing them could credibly change the rank -
ing of the alternatives). Generally, a single alternative 
should be recommended. However, if the alternatives 
do not significantly differ, or if uncertainty reduction 
could credibly alter the ranking, the recommenda -
tion should include all closely ranked alternatives for 
a final selection by the decision-maker. In any case,

a final selection by the decision-maker. In any case, 
the decision-maker is always free to select any alter -
native or ask for additional alternatives to be assessed 
(often with updated guidance on selection criteria). 
This step includes documenting the information, 
including assumptions and limitations of the evalu -
ation methods used, and analysis of the uncertainty 
in the analysis of the alternatives’ performance that 
justifies the recommendations made and gives the 
impacts of taking the recommended course of action, 
including whether further uncertainty reduction 
would be justifiable.
The highest score (e.g., percentage, total score) is 
typically the option that is recommended to man -
agement. If a different option is recommended, an 
explanation should be provided as to why the lower 
score is preferred. Usually, if an alternative having 
a lower score is recommended, the “risks” or “dis -
advantages” were too great for the highest ranking 
alternative indicating the scoring methods did not 
properly rank the alternatives. Sometimes the bene -
fits and advantages of a lower or close score outweigh 
the highest score. If this occurs, the decision criteria 
should be reevaluated, not only the weights, but the 1706.0 Crosscutting Technical Management
basic definitions of what is being measured for each 
alternative. The criteria should be updated, with con -
currence from the decision-maker, to more correctly 
reflect the suitability of each alternative.
6.8.1.2.6 Report Analysis Results
These results are reported to the appropriate stake -
holders with recommendations, impacts, and correc -
tive actions
6.8.1.2.7 Capture Work Products
These work products may include the decision anal -
ysis guidelines, strategy, and procedures that were 
used; analysis/evaluation approach; criteria, meth -
ods, and tools used; analysis/evaluation assumptions 
made in arriving at recommendations; uncertainties; 
sensitivities of the recommended actions or corrective 
actions; and lessons learned.
6.8.1.3 Outputs
6.8.1.3.1  Alternative Selection and Decision Support 
Recommendations and Impacts
Once the technical team recommends an alterna -
tive to a NASA decision-maker (e.g., a NASA board, 
forum, or panel), all decision analysis information 
should be documented. The team should produce a 
report to document all major recommendations to 
serve as a backup to any presentation materials used. 
A report in conjunction with a decision matrix pro -
vides clearly documented rationale for the presen -
tation materials (especially for complex decisions). 
Decisions are typically captured in meeting minutes 
and should be captured in the report as well. Based 
on the mission and system context and the decision 
made, the report may be a simple white paper or a 
more formally formatted document. The important 
characteristic of the report is the content, which fully 
documents the decision needed, assessments done, 
recommendations, and decision finally made.This report includes the following:
• mission and system context for the decision
• decision needed and intended outcomes
• decision criteria
• identified alternative solutions
• decision evaluation methods and tools employed
• assumptions, uncertainties, and sensitivities in 
the evaluations and recommendations
• results of all alternative evaluations
• alternative recommendations
• final decision made with rationale
• lessons learned
Typical information captured in a decision report is 
shown in TABLE 6.8-1 .
6.8.2  Decision Analysis Guidance
Refer to Section 6.8.2 in the NASA Expanded 
ance on decision analysis methods supporting all SE 
processes and phases including:
• trade studies,
• cost-benefit analysis,
• influence diagrams,
• decision trees,
• analytic hierarchy process,
• Borda counting, and
• utility analysis,
Additional information on tools for decision making 
can be found in NASA Reference Publication 1358, 
System Engineering “Toolbox” for Design-Oriented 
Engineers  located at https://nen.nasa.gov/web/se/
doc-repository .1716.0 Crosscutting Technical Management
TABLE 6.8 -1 Typical Information to Capture in a Decision Report
#Section Section Description
1 Executive 
SummaryProvide a short half-page executive summary of the report:
• Recommendation (short summary—1 sentence)
• Problem/issue requiring a decision (short summary—1 sentence)
2 Problem/Issue 
DescriptionDescribe the problem/issue that requires a decision. Provide background, history, the 
decision maker(s) (e.g., board, panel, forum, council), and decision recommendation team, 
etc.
3 Decision Matrix 
Setup RationaleProvide the rationale for setting up the decision matrix:
• Criteria selected
• Options selected
• Weights selected
• Evaluation methods selected
Provide a copy of the setup decision matrix.
4 Decision Matrix 
Scoring RationaleProvide the rationale for the scoring of the decision matrix. Provide the results of populating 
the scores of the matrix using the evaluation methods selected.
5 Final Decision 
MatrixCut and paste the final spreadsheet into the document. Also include any important 
snapshots of the decision matrix.
6 Risk/Benefits For the final options being considered, document the risks and benefits of each option.
7 Recommendation 
and/or Final 
DecisionDescribe the recommendation that is being made to the decision maker(s) and the rationale 
for why the option was selected. Can also document the final decision in this section.
8 Dissent If applicable, document any dissent with the recommendation. Document how dissent was 
addressed (e.g., decision matrix, risk).
9 References Provide any references.
A Appendices Provide the results of the literature search, including lessons learned, previous related 
decisions, and previous related dissent. Also document any detailed data analysis and risk 
analysis used for the decision. Can also document any decision metrics.1726.0 Crosscutting Technical Management
NASA SYSTEMS ENGINEERING HANDBOOK173
Appendix A: Acronyms
AADL Architecture Analysis and Design Language
AD2Advancement Degree of Difficulty 
Assessment
AIAA American Institute of Aeronautics and Astronautics
AO Announcement of Opportunity
AS9100 Aerospace Quality Management Standard
ASME American Society of Mechanical Engineers
ASQ American Society for Quality
CAIB Columbia Accident Investigation Board
CCB Configuration Control Board
CDR Critical Design Review
CE Concurrent Engineering or Chief Engineer
CEQ Council on Environmental Quality
CERR Critical Event Readiness Review
CHSIP Commercial Human Systems Integration Processes
CI Configuration Item
CM Configuration Management
CMO Configuration Management Organization
ConOps Concept of Operations
COSPAR Committee on Space Research
COTS Commercial Off-The-Shelf
CPI Critical Program Information
CR Change Request
CRM Continuous Risk Management
CSA Configuration Status Accounting
D&C Design and Construction
DDT&E Design, Development, Test, and Evaluation
DM Data Management
DOD (U.S.) Department of Defense
DODAF DOD Architecture Framework
DR Decommissioning Review
DRM Design Reference Mission
DRR Disposal Readiness Review
EDL Entry, Descent, and LandingEEE Electrical, Electronic, and Electromechanical
EFFBD Enhanced Functional Flow Block Diagram
EIA Electronic Industries Alliance
EMC Electromagnetic Compatibility
EMI Electromagnetic Interference
EO (U.S.) Executive Order
EOM End of Mission
EVM Earned Value Management
FA Formulation Agreement
FAD Formulation Authorization Document
FAR Federal Acquisition Regulation
FCA Functional Configuration Audit
FFBD Functional Flow Block Diagram
FIPS Federal Information Processing Standard
FM Fault Management
FMEA Failure Modes and Effects Analysis
FMR Financial Management Requirements
FRR Flight Readiness Review
FTE Full Time Equivalent
GEO Geostationary
GOTS Government Off-The-Shelf
GSE Government-Supplied Equipment or Ground Support Equipment
GSFC Goddard Space Flight Center
HCD Human-Centered Design
HF Human Factors
HITL Human-In-The-Loop
HQ Headquarters
HSI Human Systems Integration
HSIP Human System Integration Plan
HWIL HardWare-In-the-Loop
I&T Integration and Test
ICD Interface Control Document/Drawing
ICP I
nterface Control Plan
IDD Interface Definition Document174
NASA SYSTEMS ENGINEERING HANDBOOKAppendix A: Acronyms
IDEF0 Integration Definition (for functional modeling)
IEEE Institute of Electrical and Electronics 
Engineers
ILS Integrated Logistics Support
INCOSE International Council on Systems Engineering
IPT Integrated Product Team
IRD Interface Requirements Document
ISO International Organization for Standardization
IT Information Technology
ITA Internal Task Agreement
ITAR International Traffic in Arms Regulation
IV&V Independent Verification and Validation
IVHM Integrated Vehicle Health Management
IWG Interface Working Group

ICP I
Engineers
JCL Joint (cost and schedule) Confidence Level
JPL Jet Propulsion Laboratory
KBSI Knowledge Based Systems, Inc.
KDP Key Decision Point
KDR Key Driving Requirement
KPP Key Performance Parameter
KSC Kennedy Space Center
LCC Life Cycle Cost
LEO Low Earth Orbit or Low Earth Orbiting
M&S Modeling and Simulation or Models and 
Simulations
MBSE Model-Based Systems Engineering
MCR Mission Concept Review
MDAA Mission Directorate Associate Administrator
MDR Mission Definition Review
MEL Master Equipment List
MODAF (U.K.) Ministry of Defense Architecture Framework
MOE Measure of Effectiveness
MOP Measure of Performance
MOTS Modified Off-The-Shelf
MOU Memorandum of Understanding
MRB Material Review Board
MRR Mission Readiness Review
MSFC Marshall Space Flight Center
NASA (U.S.) National Aeronautics and Space Administration
NEN NASA Engineering Network
NEPA National Environmental Policy Act
NFS NASA FAR SupplementNGO Needs, Goals, and Objectives
NIAT NASA Integrated Action Team
NID NASA Interim Directive
NOA New Obligation Authority
NOAA (U.S.) National Oceanic and Atmospheric Administration
NODIS NASA Online Directives Information System
NPD NASA Policy Directive
NPR NASA Procedural Requirements
NRC (U.S.) Nuclear Regulatory Commission
NSTS National Space Transportation System
OCE (NASA) Office of the Chief Engineer
OCIO (NASA) Office of the Chief Information Officer
OCL Object Constraint Language
OMB (U.S.) Office of Management and Budget
ORR Operational Readiness Review
OTS Off-the-Shelf
OWL Web Ontology Language
PBS Product Breakdown Structure
PCA Physical Configuration Audit or Program Commitment Agreement
PD/NSC (U.S.) Presidential Directive/National 
Security Council
PDR Preliminary Design Review
PFAR Post-Flight Assessment Review
PI
Performance Index or Principal Investigator
PIR Program Implementation Review
PKI Public Key Infrastructure
PLAR Post-Launch Assessment Review
PM Program Manager or Project Manager
PMC Program Management Council
PPD (U.S.) Presidential Policy Directive
PRA Probabilistic Risk Assessment
PRD Project Requirements Document
PRR Production Readiness Review
QA Quality Assurance
QVT Query View Transformations
R&M Reliability and Maintainability
R&T Research and Technology
RACI Responsible, Accountable, Consulted, 
Informed
REC Record of Environmental Consideration
RF Radio Frequency175
RFA Requests for Action
RFP Request for Proposal
RID Review Item Discrepancy or Review Item 
Disposition
RIDM Risk-Informed Decision-Making
RM Risk Management
RMA Rapid Mission Architecture
RUL Remaining Useful Life
SAR System Acceptance Review or Safety 
Analysis Report (DOE)
SBU Sensitive But Unclassified
SDR Program/System Definition Review
SE Systems Engineering
SECoP Systems Engineering Community of Practice
SEMP Systems Engineering Management Plan
SI International System of Units (French: 
Système international d’unités)
SIR System Integration Review
SMA Safety and Mission Assurance
SME Subject Matter Expert
SOW Statement Of Work
SP Special Publication
SRD System Requirements DocumentSRR Program/System Requirements Review
SRS Software Requirements Specification
STI Scientific and Technical Information
STS Space Transportation System
SysML System Modeling Language
T&E Test and Evaluation
TA Technical Authority
TBD To Be Determined
TBR To Be Resolved
ToR Terms of Reference
TPM Technical Performance Measure
TRL Technology Readiness Level
TRR Test Readiness Review
TVC Thrust Vector Controller
UFE Unallocated Future Expenses
UML Unified Modeling Language
V&V Verification and Validation
WBS Work Breakdown Structure
WYE Work Year Equivalent
XMI XML Metadata Interchange
XML Extensible Markup Language176
Appendix B: Glossary
Acceptable Risk: The risk that is understood and 
agreed to by the program/project, governing author -
ity, mission directorate, and other customer(s) such 
that no further specific mitigating action is required.
Acquisition: The process for obtaining the systems, 
research, services, construction, and supplies that NASA needs to fulfill its missions. Acquisition, which may include procurement (contracting for products and services), begins with an idea or pro -
posal that aligns with the NASA Strategic Plan and fulfills an identified need and ends with the comple -
tion of the program or project or the final disposition of the product or service.
Activity: A set of tasks that describe the technical 
effort to accomplish a process and help generate expected outcomes.
Advancement Degree of Difficulty Assessment 
(AD2): The process to develop an understanding 
of what is required to advance the level of system 
maturity.
Allocated Baseline (Phase C): The allocated base -
line is the approved performance-oriented configu -
ration documentation for a CI to be developed that describes the functional and interface characteristics that are allocated from a higher level requirements document or a CI and the verification required to demonstrate achievement of those specified charac -
teristics. The allocated baseline extends the top-level performance requirements of the functional baseline to sufficient detail for initiating manufacturing or coding of a CI. The allocated baseline is controlled by NASA. The allocated baseline(s) is typically estab -
lished at the Preliminary Design Review.
Analysis: Use of mathematical modeling and analytical 
techniques to predict the compliance of a design to its requirements based on calculated data or data derived from lower system structure end product validations.
Analysis of Alternatives: A formal analysis method 
that compares alternative approaches by estimating their ability to satisfy mission requirements through an effectiveness analysis and by estimating their life cycle costs through a cost analysis. The results of these two analyses are used together to produce a cost-effectiveness comparison that allows decision makers to assess the relative value or potential pro -
grammatic returns of the alternatives. An analysis of alternatives broadly examines multiple elements of program or project alternatives (including technical performance, risk, LCC, and programmatic aspects).
Analytic Hierarchy Process: A multi-attribute meth -
odology that provides a proven, effective means to deal with complex decision- making and can assist with identifying and weighting selection criteria, analyzing the data collected for the criteria, and expe -
diting the decision-making process.
Anomaly: The unexpected performance of intended 
function.177
NASA SYSTEMS ENGINEERING HANDBOOKAppendix B: Glossary
Approval: Authorization by a required management 
official to proceed with a proposed course of action. 
Approvals are documented.
Approval (for Implementation): The acknowledg -
ment by the decision authority that the program/
project has met stakeholder expectations and for -
mulation requirements, and is ready to proceed to 
implementation. By approving a program/project, 
the decision authority commits the budget resources 
necessary to continue into implementation. Approval 
(for Implementation) is documented.
Architecture (System): Architecture is the high-level 
unifying structure that defines a system. It provides 
a set of rules, guidelines, and constraints that defines 
a cohesive and coherent structure consisting of con -
stituent parts, relationships and connections that 
establish how those parts fit and work together. It 
addresses the concepts, properties and characteristics 
of the system and is represented by entities such as 
functions, functional flows, interfaces, relationships, 
resource flow items, physical elements, containers, 
modes, links, communication resources, etc. The 
entities are not independent but interrelated in the 
architecture through the relationships between them 
(NASA HQ).
Architecture (ISO Definition): Fundamental concepts 
or properties of a system in its environment embod -
ied in its elements, relationships, and in the principles 
of its design and evolution (ISO 42010).
As-Deployed Baseline: The as-deployed baseline 
occurs at the Operational Readiness Review. At this 
point, the design is considered to be functional and 
ready for flight. All changes will have been incorpo -
rated into the documentation.
Automated: Automation refers to the allocation of 
system functions to machines (hardware or software) 
versus humans.Autonomous: Autonomy refers to the relative loca -
tions and scope of decision-making and control func -
tions between two locations within a system or across 
the system boundary.
Baseline : An agreed-to set of requirements, designs, 
or documents that will have changes controlled 
through a formal approval and monitoring process.
Bidirectional Traceability : The ability to trace any 
given requirement/expectation to its parent require -
ment/expectation and to its allocated children 
requirements/expectations.
Brassboard: A medium fidelity functional unit that

Brassboard: A medium fidelity functional unit that 
typically tries to make use of as much operational 
hardware/software as possible and begins to address 
scaling issues associated with the operational sys -
tem. It does not have the engineering pedigree in 
all aspects, but is structured to be able to operate in 
simulated operational environments in order to assess 
performance of critical functions.
Breadboard: A low fidelity unit that demonstrates 
function only, without respect to form or fit in the 
case of hardware, or platform in the case of software. 
It often uses commercial and/or ad hoc components 
and is not intended to provide definitive information 
regarding operational performance.
Component Facilities: Complexes that are geo -
graphically separated from the NASA Center or 
institution to which they are assigned, but are still 
part of the Agency.
Concept of Operations (ConOps) (Concept 
Documentation): Developed early in Pre-Phase A, 
the ConOps describes the overall high-level concept 
of how the system will be used to meet stakeholder 
expectations, usually in a time-sequenced manner. It 
describes the system from an operational perspective 
and helps facilitate an understanding of the system 178
goals. It stimulates the development of the require -
ments and architecture related to the user elements 
of the system. It serves as the basis for subsequent 
definition documents and provides the foundation 
for the long-range operational planning activities.
Concurrence: A documented agreement by a manage -
ment official that a proposed course of action is acceptable.
Concurrent Engineering: Design in parallel rather 
than serial engineering fashion. It is an approach to 
product development that brings manufacturing, 
testing, assurance, operations and other disciplines 
into the design cycle to ensure all aspects are incorpo -
rated into the design and thus reduce overall product 
development time.
Configuration Items (CI): Any hardware, software, or 
combination of both that satisfies an end use func -
tion and is designated for separate configuration 
management. For example, configuration items can 
be referred to by an alphanumeric identifier which 
also serves as the unchanging base for the assignment 
of serial numbers to uniquely identify individual 
units of the CI.
Configuration Management Process: A management 
discipline that is applied over a product’s life cycle to 
provide visibility into and to control changes to perfor -
mance and functional and physical characteristics. It 
ensures that the configuration of a product is known 
and reflected in product information, that any prod -
uct change is beneficial and is effected without adverse 
consequences, and that changes are managed.
Context Diagram: A diagram that shows external sys -
tems that impact the system being designed.
Continuous Risk Management: A systematic and 
iterative process that efficiently identifies, ana -
lyzes, plans, tracks, controls, communicates, and documents risks associated with implementation of 
designs, plans, and processes.
Contract: A mutually binding legal relationship obli -
gating the seller to furnish the supplies or services 
(including construction) and the buyer to pay for 
them. It includes all types of commitments that obli -
gate the Government to an expenditure of appropri -
ated funds and that, except as otherwise authorized, 
are in writing. In addition to bilateral instruments, 
contracts include (but are not limited to) awards and 
notices of awards; job orders or task letters issued 
under basic ordering agreements; letter contracts; 
orders, such as purchase orders under which the 
contract becomes effective by written acceptance or 
performance; and bilateral contract modifications. 
Contracts do not include grants and cooperative 
agreements.
Contractor: An individual, partnership, company, 
corporation, association, or other service having a 
contract with the Agency for the design, develop -
ment, manufacture, maintenance, modification, 
operation, or supply of items or services under the 
terms of a contract to a program or project. Research 
grantees, research contractors, and research subcon -
tractors are excluded from this definition.
Control Account Manager: A manager responsible 
for a control account and for the planning, develop -
ment, and execution of the budget content for those 
accounts.
Control Gate (or milestone): A defined point in 
the program/project life cycle where the decision 
authority can evaluate progress and determine next 
actions. These may include a key decision point, life 
cycle review, or other milestones identified by the 
program/project.179
Cost-Benefit Analysis: A methodology to determine 
the advantage of one alternative over another in terms 
of equivalent cost or benefits. It relies on totaling pos -
itive factors and subtracting negative factors to deter -
mine a net result.
Cost-Effectiveness Analysis: A systematic quanti -
tative method for comparing the costs of alternative 
means of achieving the same equivalent benefit for a 
specific objective.
Critical Design Review: A review that demonstrates 
that the maturity of the design is appropriate to sup -
port proceeding with full-scale fabrication, assembly, 
integration, and test, and that the technical effort is 
on track to complete the system development meet -
ing performance requirements within the identified 
cost and schedule constraints.
Critical Event (or key event): An event in the opera -
tions phase of the mission that is time-sensitive and is 
required to be accomplished successfully in order to 
achieve mission success. These events should be consid -
ered early in the life cycle as drivers for system design.
Critical Event Readiness Review: A review that eval -
uates the readiness of a project’s flight system to exe -
cute the critical event during flight operation.
Customer: The organization or individual that has 
requested a product and will receive the product to 
be delivered. The customer may be an end user of 
the product, the acquiring agent for the end user, or 
the requestor of the work products from a technical 
effort. Each product within the system hierarchy has 
a customer.
Data Management: DM is used to plan for, acquire, 
access, manage, protect, and use data of a technical 
nature to support the total life cycle of a system.Decision Analysis Process: A methodology for 
making decisions that offers techniques for model -
ing decision problems mathematically and finding 
optimal decisions numerically. The methodology 
entails identifying alternatives, one of which should 
be decided upon; possible events, one of which occurs 
thereafter; and outcomes, each of which results from 
a combination of decision and event.
Decision Authority: The individual authorized by the 
Agency to make important decisions for programs 
and projects under his or her authority.
Decision Matrix: A methodology for evaluating 
alternatives in which valuation criteria are typically 
displayed in rows on the left side of the matrix and 
alternatives are the column headings of the matrix. A 
“weight” is typically assigned to each criterion.
Decision Support Package: Documentation submitted 
in conjunction with formal reviews and change requests.
Decision Tree: A decision model that displays the 
expected consequences of all decision alternatives by 
making discreet all “chance” nodes, and, based on 
this, calculating and appropriately weighting the pos -
sible consequences of all alternatives.
Decommissioning Review: A review that confirms 
the decision to terminate or decommission a system 
and assess the readiness for the safe decommissioning 
and disposal of system assets. The DR is normally 
held near the end of routine mission operations upon 
accomplishment of planned mission objectives. It 
may be advanced if some unplanned event gives rise 
to a need to prematurely terminate the mission, or 
delayed if operational life is extended to permit addi -
tional investigations.
Deliverable Data Item: Consists of technical 
data, such as requirements specifications, design 180
documents, management data plans, and metrics 
reports, that have been identified as items to be deliv -
ered with an end product.
Demonstration: Showing that the use of an end 
product achieves the individual specified requirement 
(verification) or stakeholder expectation (validation). 
It is generally a basic confirmation of performance 
capability, differentiated from testing by the lack of 
detailed data gathering. Demonstrations can involve 
the use of physical models or mock-ups; for example, 
a requirement that all controls shall be reachable by 
the pilot could be verified by having a pilot perform 
flight-related tasks in a cockpit mock-up or simulator. 
A demonstration could also be the actual operation

A demonstration could also be the actual operation 
of the end product by highly qualified personnel, 
such as test pilots, who perform a one-time event that 
demonstrates a capability to operate at extreme limits 
of system performance.
Derived Requirements: Requirements arising from 
constraints, consideration of issues implied but not 
explicitly stated in the high-level direction provided 
by NASA Headquarters and Center institutional 
requirements, factors introduced by the selected 
architecture, and the design. These requirements are 
finalized through requirements analysis as part of 
the overall systems engineering process and become 
part of the program or project requirements baseline. 
Requirements arising from constraints, consideration 
of issues implied but not explicitly stated in the high-
level direction provided by NASA Headquarters and 
Center institutional requirements, factors introduced 
by the selected architecture, and the design. These 
requirements are finalized through requirements 
analysis as part of the overall systems engineering 
process and become part of the program or project 
requirements baseline.
Descope: As a verb, take out of (or remove from) 
the scope of a project. As a noun, as in “performance descope,” it indicates the process or the result of the 
process of narrowing the scope; i.e., removing part of 
the original scope.
Design Solution Definition Process: The process used 
to translate the outputs of the logical decomposition 
process into a design solution definition. It includes 
transforming the defined logical decomposition 
models and their associated sets of derived technical 
requirements into alternative solutions and analyzing 
each alternative to be able to select a preferred alterna -
tive and fully define that alternative into a final design 
solution that will satisfy the technical requirements.
Designated Governing Authority: For the technical 
effort, this is the Center Director or the person that 
has been designated by the Center Director to ensure 
the appropriate level of technical management over -
sight. For large programs, this will typically be the 
Engineering Technical Authority. For smaller proj -
ects, this function can be delegated to line managers.
Detection: Determination that system state or behav -
ior is different from expected performance.
Diagnosis: Determining the possible locations and/
or causes of an anomaly or a failure.
Discrepancy: Any observed variance from, lack of 
agreement with, or contradiction to the required or 
expected outcome, configuration, or result.
Earned Value: The sum of the budgeted cost for tasks 
and products that have actually been produced (com -
pleted or in progress) at a given time in the schedule.
Earned Value Management: A tool for measur -
ing and assessing project performance through the 
integration of technical scope with schedule and 
cost objectives during the execution of the project. 
EVM provides quantification of technical progress, 181
enabling management to gain insight into project sta -
tus and project completion costs and schedules. Two 
essential characteristics of successful EVM are EVM 
system data integrity and carefully targeted monthly 
EVM data analyses (i.e., risky WBS elements).
Emergent Behavior: An unanticipated behavior 
shown by a system due to interactions between large 
numbers of simple components of that system.
End Product: The hardware/software or other prod -
uct that performs the operational functions. This 
product is to be delivered to the next product layer or 
to the final customer.
Enabling Products: The life cycle support products 
and services (e.g., production, test, deployment, 
training, maintenance, and disposal) that facili -
tate the progression and use of the operational end 
product through its life cycle. Since the end prod -
uct and its enabling products are interdependent, 
they are viewed as a system. Project responsibility 
thus extends to acquiring services from the relevant 
enabling products in each life cycle phase. When a 
suitable enabling product does not already exist, 
the project that is responsible for the end product 
may also be responsible for creating and using the 
enabling product.
Engineering Unit: A high fidelity unit that demon -
strates critical aspects of the engineering processes 
involved in the development of the operational unit. 
Engineering test units are intended to closely resem -
ble the final product (hardware/software) to the max -
imum extent possible and are built and tested so as to 
establish confidence that the design will function in 
the expected environments. In some cases, the engi -
neering unit will become the final product, assuming 
that proper traceability has been exercised over the 
components and hardware handling.Enhanced Functional Flow Block Diagram: A block 
diagram that represents control flows and data flows 
as well as system functions and flow.
Entrance Criteria: Guidance for minimum accom -
plishments each project needs to fulfill prior to a life 
cycle review.
Environmental Impact: The direct, indirect, or 
cumulative beneficial or adverse effect of an action 
on the environment.
Environmental Management: The activity of ensur -
ing that program and project actions and decisions 
that potentially impact or damage the environment 
are assessed and evaluated during the formulation 
and planning phase and reevaluated throughout 
implementation. This activity is performed according 
to all NASA policy and Federal, state, and local envi -
ronmental laws and regulations.
Establish (with respect to processes): The act of 
developing policy, work instructions, or procedures 
to implement process activities.
Evaluation: The continual self- and independent 
assessment of the performance of a program or proj -
ect and incorporation of the evaluation findings to 
ensure adequacy of planning and execution accord -
ing to plan.
Extensibility: The ability of a decision to be extended 
to other applications.
Failure: The inability of a system, subsystem, com -
ponent, or part to perform its required function 
within specified limits (Source: NPR 8715.3 and 
Avizienis  2004).
Failure Tolerance: The ability to sustain a certain 
number of failures and still retain capability (Source: 182
NPR 8705.2). A function should be preserved despite 
the presence of any of a specified number of coinci -
dent, independent failure causes of specified types.
Fault: A physical or logical cause, which explains a 
failure (Source: Avizienis 2004).
Fault Identification: Determining the possible loca -
tions of a failure or anomaly cause(s), to a defined 
level of granularity.
Fault Isolation: The act of containing the effects of a 
fault to limit the extent of failure.
Fault Management: A specialty engineering disci -
pline that encompasses practices that enable an oper -
ational system to contain, prevent, detect, diagnose, 
identify, respond to, and recover from conditions that 
may interfere with nominal mission operations.
Fault Tolerance: See “Failure Tolerance.”
Feasible: Initial evaluations show that the concept 
credibly falls within the technical cost and schedule 
constraints for the project.
Flexibility: The ability of a decision to support more 
than one current application.
Flight Readiness Review: A review that examines 
tests, demonstrations, analyses, and audits that 
determine the system’s readiness for a safe and 
successful flight/launch and for subsequent flight 
operations. It also ensures that all flight and ground 
hardware, software, personnel, and procedures are 
operationally ready.
Float: The amount of time that a task in a project net -
work schedule can be delayed without causing a delay 
to subsequent tasks or the project completion date.Formulation Phase: The first part of the NASA man -
agement life cycle defined in NPR 7120.5 where sys -
tem requirements are baselined, feasible concepts are 
determined, a system definition is baselined for the 
selected concept(s), and preparation is made for pro -
gressing to the Implementation Phase.
Functional Analysis: The process of identifying, 
describing, and relating the functions a system should 
perform to fulfill its goals and objectives.
Functional Baseline (Phase B): The functional base -
line is the approved configuration documentation 
that describes a system’s or top-level CIs’ performance 
requirements (functional, interoperability, and inter -
face characteristics) and the verification required 
to demonstrate the achievement of those specified 
characteristics.
Functional Configuration Audit (FCA): Examines the 
functional characteristics of the configured product 
and verifies that the product has met, via test results, 
the requirements specified in its functional baseline 
documentation approved at the PDR and CDR plus 
any approved changes thereafter. FCAs will be con -
ducted on both hardware- and software-configured

ducted on both hardware- and software-configured 
products and will precede the PCA of the configured 
product.
Functional Decomposition: A subfunction under 
logical decomposition and design solution definition, 
it is the examination of a function to identify sub -
functions necessary for the accomplishment of that 
function and functional relationships and interfaces.
Functional Flow Block Diagram: A block diagram 
that defines system functions and the time sequence 
of functional events.
Gantt Chart: A bar chart depicting start and finish 
dates of activities and products in the WBS.183
Goal: Goals elaborate on the need and constitute a 
specific set of expectations for the system. They fur -
ther define what we hope to accomplish by address -
ing the critical issues identified during the problem 
assessment. Goals need not be in a quantitative or 
measurable form, but they must allow us to assess 
whether the system has achieved them.
Government Mandatory Inspection Points: 
Inspection points required by Federal regulations 
to ensure 100 percent compliance with safety/mis -
sion-critical attributes when noncompliance can 
result in loss of life or loss of mission.
Health Assessment: The activity under Fault Man -
agement that carries out detection, diagnosis, and 
identification of faults and prediction of fault prop -
agation states into the future.
Health Monitoring: The activity under Fault 
Management that implements system state data col -
lection, storage, and reporting though sensing and 
communication.
Heritage (or legacy): Refers to the original manufactur -
er’s level of quality and reliability that is built into the 
parts, which have been proven by (1) time in service, 
(2) number of units in service, (3) mean time between 
failure performance, and (4) number of use cycles.
Human-Centered Design: An approach to the devel -
opment of interactive systems that focuses on making 
systems usable by ensuring that the needs, abilities, 
and limitations of the human user are met through -
out the system’s life cycle.
Human Factors Engineering: The discipline that 
studies human-system interfaces and provides 
requirements, standards, and guidelines to ensure the 
human component of an integrated system is able to 
function as intended.Human Systems Integration: An interdisciplinary 
and comprehensive management and technical pro -
cess that focuses on the integration of human consid -
erations into the system acquisition and development 
processes to enhance human system design, reduce 
life cycle ownership cost, and optimize total system 
performance.
Implementation Phase: The part of the NASA man -
agement life cycle defined in NPR 7120.5 where the 
detailed design of system products is completed and the 
products to be deployed are fabricated, assembled, inte -
grated, and tested and the products are deployed to their 
customers or users for their assigned use or mission.
Incommensurable Costs: Costs that cannot be easily 
measured, such as controlling pollution on launch or 
mitigating debris.
Influence Diagram: A compact graphical and mathe -
matical representation of a decision state. Its elements are 
decision nodes, chance nodes, value nodes, and arrows 
to indicate the relationships among these elements.
Inspection: The visual examination of a realized end 
product. Inspection is generally used to verify phys -
ical design features or specific manufacturer identi -
fication. For example, if there is a requirement that 
the safety arming pin has a red flag with the words 
“Remove Before Flight” stenciled on the flag in black 
letters, a visual inspection of the arming pin flag can 
be used to determine if this requirement was met.
Integrated Logistics Support: The management, 
engineering activities, analysis, and information 
management associated with design requirements 
definition, material procurement and distribution, 
maintenance, supply replacement, transportation, 
and disposal that are identified by space flight and 
ground systems supportability objectives.184
Interface Management Process: The process to assist 
in controlling product development when efforts are 
divided among parties (e.g., Government, contrac -
tors, geographically diverse technical teams) and/or 
to define and maintain compliance among the prod -
ucts that should interoperate.
Iterative: Application of a process to the same product 
or set of products to correct a discovered discrepancy 
or other variation from requirements. (See “recursive” 
and “repeatable.”)
Key Decision Point: The event at which the decision 
authority determines the readiness of a program/proj -
ect to progress to the next phase of the life cycle (or 
to the next KDP).
Key Event (or Critical Event): See “Critical Event.”
Key Performance Parameter: Those capabilities or 
characteristics (typically engineering-based or related to 
health and safety or operational performance) consid -
ered most essential for successful mission accomplish -
ment. They characterize the major drivers of operational 
performance, supportability, and interoperability.
Knowledge Management: A collection of policies, 
processes, and practices relating to the use of intellec -
tual- and knowledge-based assets in an organization.
Least-Cost Analysis: A methodology that identifies 
the least-cost project option for meeting the techni -
cal requirements.
Liens: Requirements or tasks not satisfied that have 
to be resolved within a certain assigned time to allow 
passage through a control gate to proceed.
Life Cycle Cost (LCC): The total of the direct, indi -
rect, recurring, nonrecurring, and other related 
expenses both incurred and estimated to be incurred in the design, development, verification, production, 
deployment, prime mission operation, maintenance, 
support, and disposal of a project, including closeout, 
but not extended operations. The LCC of a project or 
system can also be defined as the total cost of own -
ership over the project or system’s planned life cycle 
from Formulation (excluding Pre–Phase A) through 
Implementation (excluding extended operations). 
The LCC includes the cost of the launch vehicle.
Logical Decomposition Models: Mathematical 
or visual representations of the relationships 
between requirements as identified in the Logical 
Decomposition Process.
Logical Decomposition Process: A process used 
to improve understanding of the defined technical 
requirements and the relationships among the require -
ments (e.g., functional, behavioral, performance, and 
temporal) and to transform the defined set of techni -
cal requirements into a set of logical decomposition 
models and their associated set of derived technical 
requirements for lower levels of the system and for 
input to the Design Solution Definition Process.
Logistics (or Integrated Logistics Support): See 
“Integrated Logistics Support.”
Loosely Coupled Program: Programs that address 
specific objectives through multiple space flight proj -
ects of varied scope. While each individual project 
has an assigned set of mission objectives, architec -
tural and technological synergies and strategies that 
benefit the program as a whole are explored during 
the formulation process. For instance, Mars orbiters 
designed for more than one Mars year in orbit are 
required to carry a communication system to support 
present and future landers.
Maintain (with respect to establishment of pro -
cesses): The act of planning the process, providing 185
resources, assigning responsibilities, training people, 
managing configurations, identifying and involving 
stakeholders, and monitoring process effectiveness.
Maintainability: The measure of the ability of an item 
to be retained in or restored to specified conditions 
when maintenance is performed by personnel having 
specified skill levels, using prescribed procedures and 
resources, at each prescribed level of maintenance.
Margin: The allowances carried in budget, projected 
schedules, and technical performance parameters 
(e.g., weight, power, or memory) to account for 
uncertainties and risks. Margins are allocated in the 
formulation process based on assessments of risks and 
are typically consumed as the program/project pro -
ceeds through the life cycle.
Master Equipment List (MEL): The MEL is a listing 
of all the parts of a system and includes pertinent 
information such as serial numbers, model numbers, 
manufacturer, equipment type, system/element it is 
located within, etc.
Measure of Effectiveness (MOE): A measure by 
which a stakeholder’s expectations are judged in 
assessing satisfaction with products or systems pro -
duced and delivered in accordance with the associated 
technical effort. The MOE is deemed to be critical to 
not only the acceptability of the product by the stake -
holder but also critical to operational/mission usage.

holder but also critical to operational/mission usage. 
A MOE is typically qualitative in nature or not able 
to be used directly as a design-to requirement.
Measure of Performance (MOP): A quantitative 
measure that, when met by the design solution, helps 
ensure that a MOE for a product or system will be 
satisfied. These MOPs are given special attention 
during design to ensure that the MOEs to which 
they are associated are met. There are generally two 
or more measures of performance for each MOE.Metric: The result of a measurement taken over a 
period of time that communicates vital information 
about the status or performance of a system, process, 
or activity. A metric should drive appropriate action.
Mission: A major activity required to accomplish an 
Agency goal or to effectively pursue a scientific, tech -
nological, or engineering opportunity directly related 
to an Agency goal. Mission needs are independent of 
any particular system or technological solution.
Mission Concept Review: A review that affirms the 
mission/project need and examines the proposed 
mission’s objectives and the ability of the concept to 
fulfill those objectives.
Mission Definition Review: A life cycle review that 
evaluates whether the proposed mission/system 
architecture is responsive to the program mission/sys -
tem functional and performance requirements and 
requirements have been allocated to all functional 
elements of the mission/system.
Mitigation: An action taken to mitigate the effects 
of a fault towards achieving existing or redefined 
system goals.
Model: A model is a physical, mathematical, or logi -
cal representation of reality.
Need: A single statement that drives everything else. 
It should relate to the problem that the system is sup -
posed to solve, but not be the solution.
Nonconforming product: Software, hardware, or 
combination, either produced, acquired, or in some 
combination that is identified as not meeting docu -
mented requirements.
Objective: Specific target levels of outputs the sys -
tem must achieve. Each objective should relate to a 186
particular goal. Generally, objectives should meet 
four criteria:
1. Specific:  Objectives should aim at results and 
reflect what the system needs to do, but they don’t 
outline how to implement the solution. They need 
to be specific enough to provide clear direction, so 
developers, customers, and testers can understand 
them.
2. Measurable:  Objectives need to be quantifiable 
and verifiable. The project needs to monitor the 
system’s success in achieving each objective.
3. Aggressive, but attainable:  Objectives need to be 
challenging but reachable, and targets need to be 
realistic. At first, objectives “To Be Determined” 
(TBD) may be included until trade studies 
occur, operations concepts solidify, or technology 
matures. But objectives need to be feasible before 
starting to write requirements and design systems.
4. Results-oriented:  Objectives need to focus on 
desired outputs and outcomes, not on the meth -
ods used to achieve the target (what, not how).
Objective Function (sometimes Cost Function): 
A mathematical expression of the values of combi -
nations of possible outcomes as a single measure of 
cost-effectiveness.
Operational Environment: The environment in 
which the final product will be operated. In the case 
of space flight hardware/software, it is space. In the 
case of ground-based or airborne systems that are not 
directed toward space flight, it is the environments 
defined by the scope of operations. For software, the 
environment is defined by the operational platform.
Operational Readiness Review: A review that exam -
ines the actual system characteristics and the proce -
dures used in the system or product’s operation and ensures that all system and support (flight and ground) 
hardware, software, personnel, procedures, and user 
documentation accurately reflects the deployed state 
of the system and are operationally ready.
Operations Concept: A description of how the flight 
system and the ground system are used together to 
ensure that the concept of operation is reasonable. This 
might include how mission data of interest, such as 
engineering or scientific data, are captured, returned to 
Earth, processed, made available to users, and archived 
for future reference. (Source: NPR 7120.5)
Optimal Solution: A feasible solution that best meets 
criteria when balanced at a system level.
Other Interested Parties (Stakeholders): A subset of 
“stakeholders,” other interested parties are groups or 
individuals who are not customers of a planned tech -
nical effort but may be affected by the resulting prod -
uct, the manner in which the product is realized or 
used, or have a responsibility for providing life cycle 
support services.
Peer Review: Independent evaluation by internal or 
external subject matter experts who do not have a 
vested interest in the work product under review. Peer 
reviews can be planned, focused reviews conducted 
on selected work products by the producer’s peers to 
identify defects and issues prior to that work product 
moving into a milestone review or approval cycle.
Performance Standards: Defines what constitutes 
acceptable performance by the provider. Common 
metrics for use in performance standards include cost 
and schedule.
Physical Configuration Audits (PCA) or configura -
tion inspection: The PCA examines the physical con -
figuration of the configured product and verifies that 
the product corresponds to the build-to (or code-to) 
product baseline documentation previously approved 187
at the CDR plus the approved changes thereafter. 
PCAs are conducted on both hardware-and soft -
ware-configured products.
Post-Flight Assessment Review: Evaluates how well 
mission objectives were met during a mission and 
identifies all flight and ground system anomalies 
that occurred during the flight and determines the 
actions necessary to mitigate or resolve the anomalies 
for future flights of the same spacecraft design.
Post-Launch Assessment Review: A review that 
evaluates the readiness of the spacecraft systems 
to proceed with full, routine operations after post-
launch deployment. The review also evaluates the sta -
tus of the project plans and the capability to conduct 
the mission with emphasis on near-term operations 
and mission-critical events.
Precedence Diagram: Workflow diagram that places 
activities in boxes connected by dependency arrows; 
typical of a Gantt chart.
Preliminary Design Review: A review that demon -
strates that the preliminary design meets all system 
requirements with acceptable risk and within the cost 
and schedule constraints and establishes the basis for 
proceeding with detailed design. It will show that the 
correct design option has been selected, interfaces 
have been identified, and verification methods have 
been described.
Process: A set of activities used to convert inputs 
into desired outputs to generate expected outcomes 
and satisfy a purpose.
Producibility: A system characteristic associated with 
the ease and economy with which a completed design 
can be transformed (i.e., fabricated, manufactured, or 
coded) into a hardware and/or software realization.Product: A part of a system consisting of end prod -
ucts that perform operational functions and enabling 
products that perform life cycle services related to 
the end product or a result of the technical efforts in 
the form of a work product (e.g., plan, baseline, or 
test result).
Product Baseline (Phase D/E): The product base -
line is the approved technical documentation that 
describes the configuration of a CI during the produc -
tion, fielding/deployment, and operational support 
phases of its life cycle. The product baseline describes 
detailed physical or form, fit, and function character -
istics of a CI; the selected functional characteristics 
designated for production acceptance testing; and the 
production acceptance test requirements.
Product Breakdown Structure: A hierarchical break -
down of the hardware and software products of a 
program/project.
Product Implementation Process: A process used to 
generate a specified product of a product layer through 
buying, making, or reusing in a form consistent with 
the product life cycle phase exit (success) criteria and 
that satisfies the design solution definition-specified 
requirements (e.g., drawings, specifications).
Product Integration Process: A process used to 
transform the design solution definition into the 
desired end product of the product layer through 
assembly and integration of lower-level validated end 
products in a form that is consistent with the product 
life cycle phase exit (success) criteria and that satis -
fies the design solution definition requirements (e.g., 
drawings, specifications).
Product Realization: The act of making, buying, or

Product Realization: The act of making, buying, or 
reusing a product, or the assembly and integration 
of lower-level realized products into a new product, 
as well as the verification and validation that the 188
product satisfies its appropriate set of requirements 
and the transition of the product to its customer.
Product Transition Process: A process used to tran -
sition a verified and validated end product that has 
been generated by product implementation or prod -
uct integration to the customer at the next level in the 
system structure for integration into an end product 
or, for the top-level end product, transitioned to the 
intended end user.
Product Validation Process: A process used to con -
firm that a verified end product generated by product 
implementation or product integration fulfills (satis -
fies) its intended use when placed in its intended envi -
ronment and to assure that any anomalies discovered 
during validation are appropriately resolved prior to 
delivery of the product (if validation is done by the 
supplier of the product) or prior to integration with 
other products into a higher-level assembled product 
(if validation is done by the receiver of the product). 
The validation is done against the set of baselined 
stakeholder expectations.
Product Verification Process: A process used to 
demonstrate that an end product generated from 
product implementation or product integration con -
forms to its design solution definition requirements 
as a function of the product life cycle phase and the 
location of the product layer end product in the sys -
tem structure.
Production Readiness Review (PRR): A review for 
projects developing or acquiring multiple or similar 
systems greater than three or as determined by the 
project. The PRR determines the readiness of the 
system developers to efficiently produce the required 
number of systems. It ensures that the production 
plans, fabrication, assembly, integration-enabling 
products, operational support, and personnel are in 
place and ready to begin production.Prognosis: The prediction of a system’s future health 
states, degradation, and Remaining Useful Life (RUL).
Program: A strategic investment by a mission direc -
torate or mission support office that has a defined 
architecture and/or technical approach, require -
ments, funding level, and a management structure 
that initiates and directs one or more projects. A pro -
gram defines a strategic direction that the Agency has 
identified as critical.
Program/System Definition Review: A review that 
examines the proposed program architecture and the 
flowdown to the functional elements of the system. 
The proposed program’s objectives and the concept 
for meeting those objectives are evaluated. Key tech -
nologies and other risks are identified and assessed. 
The baseline program plan, budgets, and schedules 
are presented.
Program Requirements: The set of requirements 
imposed on the program office, which are typically 
found in the program plan plus derived requirements 
that the program imposes on itself.
Program System Requirements Review: A review 
that evaluates the credibility and responsiveness of a 
proposed program requirements/architecture to the 
mission directorate requirements, the allocation of 
program requirements to the projects, and the matu -
rity of the program’s mission/system definition.
Programmatic Requirements: Requirements set 
by the mission directorate, program, project, and 
PI, if applicable. These include strategic scientific 
and exploration requirements, system performance 
requirements, and schedule, cost, and similar non -
technical constraints.
Project: A specific investment having defined goals, 
objectives, requirements, life cycle cost, a beginning, 189
and an end. A project yields new or revised products 
or services that directly address NASA’s strategic 
needs. The products may be produced or the services 
performed wholly in-house; by partnerships with 
Government, industry, or academia; or through con -
tracts with private industry.
Project Plan: The document that establishes the 
project’s baseline for implementation, signed by the 
responsible program manager, Center Director, proj -
ect manager, and the MDAA, if required.
Project Requirements: The set of requirements 
imposed on the project and developer, which are typ -
ically found in the project plan plus derived require -
ments that the project imposes on itself. It includes 
identification of activities and deliverables (end prod -
ucts and work products) and outputs of the develop -
ment and operations.
Phase Product: An end product that is to be provided 
as a result of the activities of a given life cycle phase. 
The form depends on the phase—a product of early 
phases might be a simulation or model; a product of 
later phases may be the (final) end product itself.
Product Form: A representation of a product that 
depends on the development phase, current use, and 
maturity. Examples include mock-up, model, engi -
neering unit, prototype unit, and flight unit.
Product Realization: The desired output from the appli -
cation of the four product realization processes. The 
form of this product is dependent on the phase of the 
product life cycle and the phase exit (success) criteria.
Prototype: The prototype unit demonstrates form, 
fit, and function at a scale deemed to be representa -
tive of the final product operating in its operational 
environment. A subscale test article provides fidelity 
sufficient to permit validation of analytical mod -
els capable of predicting the behavior of full-scale systems in an operational environment. The proto -
type is used to “wring out” the design solution so that 
experience gained from the prototype can be fed back 
into design changes that will improve the manufac -
ture, integration, and maintainability of a single flight 
item or the production run of several flight items.
Quality Assurance: An independent assessment per -
formed throughout a product’s life cycle in order to 
acquire confidence that the system actually produced 
and delivered is in accordance with its functional, 
performance, and design requirements.
Realized Product: The end product that has been 
implemented/integrated, verified, validated, and 
transitioned to the next product layer.
Recovery: An action taken to restore the functions 
necessary to achieve existing or redefined system 
goals after a fault/failure occurs.
Recursive: Value is added to the system by the 
repeated application of processes to design next low -
er-layer system products or to realize next upper-layer 
end products within the system structure. This also 
applies to repeating the application of the same pro -
cesses to the system structure in the next life cycle 
phase to mature the system definition and satisfy 
phase exit (success) criteria.
Relevant Stakeholder: A subset of the term “stake -
holder” that applies to people or roles that are des -
ignated in a plan for stakeholder involvement. Since 
“stakeholder” may describe a very large number of 
people, a lot of time and effort would be consumed 
by attempting to deal with all of them. For this rea -
son, “relevant stakeholder” is used in most practice 
statements to describe the people identified to con -
tribute to a specific task.
Relevant Environment: Not all systems, subsys -
tems, and/or components need to be operated in 190
the operational environment in order to satisfacto -
rily address performance margin requirements or 
stakeholder expectations. Consequently, the relevant 
environment is the specific subset of the operational 
environment that is required to demonstrate critical 
“at risk” aspects of the final product performance in 
an operational environment.
Reliability: The measure of the degree to which a 
system ensures mission success by functioning prop -
erly over its intended life. It has a low and acceptable 
probability of failure, achieved through simplicity, 
proper design, and proper application of reliable parts 
and materials. In addition to long life, a reliable sys -
tem is robust and fault tolerant.
Repeatable: A characteristic of a process that can be 
applied to products at any level of the system struc -
ture or within any life cycle phase.
Requirement: The agreed-upon need, desire, want, 
capability, capacity, or demand for personnel, equip -
ment, facilities, or other resources or services by 
specified quantities for specific periods of time or 
at a specified time expressed as a “shall” statement. 
Acceptable form for a requirement statement is indi -
vidually clear, correct, feasible to obtain, unambig -
uous in meaning, and can be validated at the level 
of the system structure at which it is stated. In pairs 
of requirement statements or as a set, collectively,

of requirement statements or as a set, collectively, 
they are not redundant, are adequately related with 
respect to terms used, and are not in conflict with 
one another.
Requirements Allocation Sheet: Documents the 
connection between allocated functions, allocated 
performance, and the physical system.
Requirements Management Process: A process 
used to manage the product requirements identified, 
baselined, and used in the definition of the products of each product layer during system design. It pro -
vides bidirectional traceability back to the top prod -
uct layer requirements and manages the changes to 
established requirement baselines over the life cycle 
of the system products.
Risk: In the context of mission execution, risk is the 
potential for performance shortfalls that may be real -
ized in the future with respect to achieving explicitly 
established and stated performance requirements. 
The performance shortfalls may be related to any one 
or more of the following mission execution domains: 
(1) safety, (2) technical, (3) cost, and (4) schedule. 
(Source: NPR 8000.4, Agency Risk Management 
Procedural Requirements)
Risk Assessment: An evaluation of a risk item that 
determines (1) what can go wrong, (2) how likely it 
is to occur, (3) what the consequences are, and (4) 
what the uncertainties associated with the likelihood 
and consequences are, and 5) what the mitigation 
plans are.
Risk-Informed Decision Analysis Process: A five-
step process focusing first on objectives and next 
on developing decision alternatives with those 
objectives clearly in mind and/or using decision 
alternatives that have been developed under other 
systems engineering processes. The later steps of the 
process interrelate heavily with the Technical Risk 
Risk Management: Risk management includes 
Risk-Informed Decision-Making (RIDM) and 
Continuous Risk Management (CRM) in an inte -
grated framework. RIDM informs systems engi -
neering decisions through better use of risk and 
uncertainty information in selecting alternatives and 
establishing baseline requirements. CRM manages 
risks over the course of the development and the 
Implementation Phase of the life cycle to ensure that 191
safety, technical, cost, and schedule requirements 
are met. This is done to foster proactive risk man -
agement, to better inform decision-making through 
better use of risk information, and then to more effec -
tively manage Implementation risks by focusing the 
CRM process on the baseline performance require -
ments emerging from the RIDM process. (Source: 
NPR 8000.4, Agency Risk Management Procedural 
Requirements) These processes are applied at a level 
of rigor commensurate with the complexity, cost, and 
criticality of the program.
Safety: Freedom from those conditions that can 
cause death, injury, occupational illness, damage to 
or loss of equipment or property, or damage to the 
environment.
Search Space (or Alternative Space): The envelope 
of concept possibilities defined by design constraints 
and parameters within which alternative concepts 
can be developed and traded off.
Single-Project Programs: Programs that tend to 
have long development and/or operational lifetimes, 
represent a large investment of Agency resources, and 
have contributions from multiple organizations/agen -
cies. These programs frequently combine program 
and project management approaches, which they 
document through tailoring.
Software: Computer programs, procedures, rules, 
and associated documentation and data pertaining 
to the development and operation of a computer sys -
tem. Software also includes Commercial Off-The-
Shelf (COTS), Government Off-The-Shelf (GOTS), 
Modified Off-The-Shelf (MOTS), embedded soft -
ware, reuse, heritage, legacy, autogenerated code, 
firmware, and open source software components.
Note 1:  For purposes of the NASA Software Release 
program only, the term “software,” as redefined in NPR 2210.1, Release of NASA Software, does not include 
computer databases or software documentation.
Note 2: Definitions for the terms COTS, GOTS, 
heritage software, MOTS, legacy software, software 
reuse, and classes of software are provided in NPR 
7150.2, NASA Software Engineering Requirements. 
(Source: NPD 7120.4, NASA Engineering and 
Program/Project Management Policy)
Solicitation: The vehicle by which information is 
solicited from contractors for the purpose of award -
ing a contract for products or services. Any request 
to submit offers or quotations to the Government. 
Solicitations under sealed bid procedures are called 
“invitations for bids.” Solicitations under negoti -
ated procedures are called “requests for proposals.” 
Solicitations under simplified acquisition procedures 
may require submission of either a quotation or 
an offer.
Specification: A document that prescribes com -
pletely, precisely, and verifiably the requirements, 
design, behavior, or characteristics of a system or 
system component. In NPR 7123.1, “specification” is 
treated as a “requirement.”
Stakeholder: A group or individual who is affected 
by or has an interest or stake in a program or project. 
There are two main classes of stakeholders. See “cus -
tomers” and “other interested parties.”
Stakeholder Expectations: A statement of needs, 
desires, capabilities, and wants that are not expressed 
as a requirement (not expressed as a “shall” statement) 
is referred to as an “expectation.” Once the set of 
expectations from applicable stakeholders is collected, 
analyzed, and converted into a “shall” statement, the 
expectation becomes a requirement. Expectations 
can be stated in either qualitative (non-measurable) 
or quantitative (measurable) terms. Requirements are 192
always stated in quantitative terms. Expectations can 
be stated in terms of functions, behaviors, or con -
straints with respect to the product being engineered 
or the process used to engineer the product.
Stakeholder Expectations Definition Process: A 
process used to elicit and define use cases, scenarios, 
concept of operations, and stakeholder expectations 
for the applicable product life cycle phases and prod -
uct layer. The baselined stakeholder expectations are 
used for validation of the product layer end product.
Standing Review Board: The board responsible for 
conducting independent reviews (life-cycle and spe -
cial) of a program or project and providing objective, 
expert judgments to the convening authorities. The 
reviews are conducted in accordance with approved 
Terms of Reference (ToR) and life cycle requirements 
per NPR 7123.1.
State Diagram: A diagram that shows the flow in the 
system in response to varying inputs in order to char -
acterize the behavior of the system.
Success Criteria: Specific accomplishments that 
need to be satisfactorily demonstrated to meet the 
objectives of a technical review so that a technical 
effort can progress further in the life cycle. Success 
criteria are documented in the corresponding techni -
cal review plan. Formerly referred to as “exit” criteria, 
a term still used in some NPDs/NPRs.
Surveillance : The monitoring of a contractor’s activ -
ities (e.g., status meetings, reviews, audits, site visits) 
for progress and production and to demonstrate fis -
cal responsibility, ensure crew safety and mission suc -
cess, and determine award fees for extraordinary (or 
penalty fees for substandard) contract execution.
System: (1) The combination of elements that func -
tion together to produce the capability to meet a need. The elements include all hardware, software, 
equipment, facilities, personnel, processes, and pro -
cedures needed for this purpose. (2) The end product 
(which performs operational functions) and enabling 
products (which provide life cycle support services to 
the operational end products) that make up a system.
System Acceptance Review: The SAR verifies the 
completeness of the specific end products in relation 
to their expected maturity level, assesses compliance 
to stakeholder expectations, and ensures that the 
system has sufficient technical maturity to authorize 
its shipment to the designated operational facility or 
launch site.
System Definition Review: The Mission/System 
Definition Review (MDR/SDR) evaluates whether 
the proposed mission/system architecture is respon -
sive to the program mission/system functional and 
performance requirements and requirements have 
been allocated to all functional elements of the mis -
sion/system. This review is used for projects and for 
single-project programs.
System Integration Review: A SIR ensures that seg -
ments, components, and subsystems are on schedule 
to be integrated into the system and that integration 
facilities, support personnel, and integration plans and 
procedures are on schedule to support integration.
System Requirements Review: For a program, the

System Requirements Review: For a program, the 
SRR is used to ensure that its functional and per -
formance requirements are properly formulated and 
correlated with the Agency and mission directorate 
strategic objectives.
For a system/project, the SRR evaluates whether the 
functional and performance requirements defined for 
the system are responsive to the program’s require -
ments and ensures that the preliminary project plan 
and requirements will satisfy the mission.193
System Safety Engineering: The application of engi -
neering and management principles, criteria, and 
techniques to achieve acceptable mishap risk within 
the constraints of operational effectiveness and suit -
ability, time, and cost throughout all phases of the 
system life cycle.
System Structure: A system structure is made up 
of a layered structure of product-based WBS mod -
els. (See “Work Breakdown Structure” and Product 
Breakdown Structure.”)
Systems Approach: The application of a systematic, 
disciplined engineering approach that is quantifiable, 
recursive, iterative, and repeatable for the develop -
ment, operation, and maintenance of systems inte -
grated into a whole throughout the life cycle of a 
project or program.
Systems Engineering (SE) Engine: The SE model 
shown in Figure 2.1-1 that provides the 17 technical 
processes and their relationships with each other. The 
model is called an “SE engine” in that the appropriate 
set of processes is applied to the products being engi -
neered to drive the technical effort.
Systems Engineering Management Plan (SEMP): 
The SEMP identifies the roles and responsibility 
interfaces of the technical effort and specifies how 
those interfaces will be managed. The SEMP is the 
vehicle that documents and communicates the tech -
nical approach, including the application of the com -
mon technical processes; resources to be used; and 
the key technical tasks, activities, and events along 
with their metrics and success criteria.
Tailoring: A process used to adjust or seek relief from 
a prescribed requirement to accommodate the needs 
of a specific task or activity (e.g., program or proj -
ect). The tailoring process results in the generation of deviations and waivers depending on the timing 
of the request.
OR
The process used to seek relief from NPR 7123.1 
requirements consistent with program or project 
objectives, allowable risk, and constraints.
Technical Assessment Process: A process used to 
help monitor progress of the technical effort and 
provide status information for support of the system 
design, product realization, and technical manage -
ment processes. A key aspect of the process is con -
ducting life cycle and technical reviews throughout 
the system life cycle.
Technical Cost Estimate: The cost estimate of the 
technical work on a project created by the techni -
cal team based on its understanding of the system 
requirements and operational concepts and its vision 
of the system architecture.
Technical Data Management Process: A process 
used to plan for, acquire, access, manage, protect, 
and use data of a technical nature to support the total 
life cycle of a system. This process is used to cap -
ture trade studies, cost estimates, technical analyses, 
reports, and other important information.
Technical Data Package: An output of the Design 
Solution Definition Process, it evolves from phase to 
phase, starting with conceptual sketches or models 
and ending with complete drawings, parts list, and 
product integration.
Technical Measures: An established set of measures 
based on the expectations and requirements that will 
be tracked and assessed to determine overall system or 194
product effectiveness and customer satisfaction. Com -
mon terms for these measures are Measures Of Effec -
tiveness (MOEs), Measures Of Performance (MOPs), 
and Technical Performance Measures (TPMs).
Technical Performance Measures: A set of perfor -
mance measures that are monitored by comparing 
the current actual achievement of the parameters 
with that anticipated at the current time and on 
future dates. TPMs are used to confirm progress and 
identify deficiencies that might jeopardize meeting a 
system requirement. Assessed parameter values that 
fall outside an expected range around the anticipated 
values indicate a need for evaluation and corrective 
action. Technical performance measures are typi -
cally selected from the defined set of Measures Of 
Performance (MOPs).
Technical Planning Process: A process used to plan 
for the application and management of each common 
technical process. It is also used to identify, define, 
and plan the technical effort applicable to the prod -
uct life cycle phase for product layer location within 
the system structure and to meet project objectives 
and product life cycle phase exit (success) criteria. A 
key document generated by this process is the SEMP.
Technical Requirements: A set of requirements imposed 
on the end products of the system, including the system 
itself. Also referred to as “product requirements.”
Technical Requirements Definition Process: A pro -
cess used to transform the stakeholder expectations 
into a complete set of validated technical require -
ments expressed as “shall” statements that can be 
used for defining a design solution for the Product 
Breakdown Structure (PBS) model and related 
enabling products.
Technical Risk: Risk associated with the achievement 
of a technical goal, criterion, or objective. It applies to undesired consequences related to technical perfor -
mance, human safety, mission assets, or environment.
Technical Risk Management Process: A process 
used to make risk-informed decisions and examine, 
on a continuing basis, the potential for deviations 
from the project plan and the consequences that 
could result should they occur.
Technical Team: A group of multidisciplinary indi -
viduals with appropriate domain knowledge, experi -
ence, competencies, and skills who are assigned to a 
specific technical task.
Technology Readiness Assessment Report: A doc -
ument required for transition from Phase B to Phase 
C/D demonstrating that all systems, subsystems, and 
components have achieved a level of technological 
maturity with demonstrated evidence of qualification 
in a relevant environment.
Technology Assessment: A systematic process that 
ascertains the need to develop or infuse technologi -
cal advances into a system. The technology assess -
ment process makes use of basic systems engineering 
principles and processes within the framework of the 
Product Breakdown Structure (PBS). It is a two-step 
process comprised of (1) the determination of the cur -
rent technological maturity in terms of Technology 
Readiness Levels (TRLs) and (2) the determination 
of the difficulty associated with moving a technol -
ogy from one TRL to the next through the use of the 
Advancement Degree of Difficulty Assessment (AD2).
Technology Development Plan: A document required 
for transition from Phase A to Phase B identifying 
technologies to be developed, heritage systems to be 
modified, alternative paths to be pursued, fallback 
positions and corresponding performance descopes, 
milestones, metrics, and key decision points. It is 
incorporated in the preliminary project plan.195
Technology Maturity Assessment: A process to 
determine a system’s technological maturity based on 
Technology Readiness Levels (TRLs).
Technology Readiness Level: Provides a scale against 
which to measure the maturity of a technology. TRLs 
range from 1, basic technology research, to 9, systems 
test, launch, and operations. Typically, a TRL of 6 
(i.e., technology demonstrated in a relevant environ -
ment) is required for a technology to be integrated 
into an SE process.
Test: The use of a realized end product to obtain 
detailed data to verify or validate performance or to 
provide sufficient information to verify or validate 
performance through further analysis.
Test Readiness Review: A review that ensures that 
the test article (hardware/software), test facility, sup -
port personnel, and test procedures are ready for test -
ing and data acquisition, reduction, and control.
Threshold Requirements: A minimum acceptable set 
of technical and project requirements; the set could 
represent the descope position of the project.
Tightly Coupled Programs: Programs with multi -
ple projects that execute portions of a mission(s). No 
single project is capable of implementing a complete 
mission. Typically, multiple NASA Centers con -
tribute to the program. Individual projects may be 
managed at different Centers. The program may also 
include contributions from other agencies or interna -
tional partners.
Traceability: A discernible association among two or

Traceability: A discernible association among two or 
more logical entities such as requirements, system ele -
ments, verifications, or tasks.
Trade Study: A means of evaluating system designs 
by devising alternative means to meet functional requirements, evaluating these alternatives in terms of 
the measures of effectiveness and system cost, rank -
ing the alternatives according to appropriate selection 
criteria, dropping less promising alternatives, and 
proceeding to the next level of resolution, if needed.
Trade Study Report: A report written to document 
a trade study. It should include: the system under 
analysis; system goals, objectives (or requirements, as 
appropriate to the level of resolution), and constraints; 
measures and measurement methods (models) used; 
all data sources used; the alternatives chosen for anal -
ysis; computational results, including uncertainty 
ranges and sensitivity analyses performed; the selec -
tion rule used; and the recommended alternative.
Trade Tree: A representation of trade study alter -
natives in which each layer represents some system 
aspect that needs to be treated in a trade study to 
determine the best alternative.
Transition: The act of delivery or moving of a product 
from one location to another. This act can include 
packaging, handling, storing, moving, transporting, 
installing, and sustainment activities.
Uncoupled Programs: Programs implemented 
under a broad theme and/or a common program 
implementation concept, such as providing frequent 
flight opportunities for cost-capped projects selected 
through AO or NASA Research Announcements. 
Each such project is independent of the other projects 
within the program.
Utility: A measure of the relative value gained from an 
alternative. The theoretical unit of measurement for 
utility is the “util.”
Validated Requirements: A set of requirements that 
are well formed (clear and unambiguous), complete 
(agree with customer and stakeholder needs and 196
expectations), consistent (conflict free), and individ -
ually verifiable and traceable to a higher level require -
ment or goal.
Validation (of a product): The process of showing 
proof that the product accomplishes the intended 
purpose based on stakeholder expectations and the 
Concept of Operations. May be determined by a 
combination of test, analysis, demonstration, and 
inspection. (Answers the question, “Am I building 
the right product?”)
Variance: In program control terminology, a differ -
ence between actual performance and planned costs 
or schedule status.
Verification (of a product): Proof of compliance with 
specifications. Verification may be determined by 
test, analysis, demonstration, or inspection or a com -
bination thereof. (Answers the question, “Did I build 
the product right?”)
Waiver: A documented authorization releasing a pro -
gram or project from meeting a requirement after the requirement is put under configuration control at the 
level the requirement will be implemented.
Work Breakdown Structure (WBS): A product-ori -
ented hierarchical division of the hardware, software, 
services, and data required to produce the program/
project’s end product(s) structured according to the 
way the work will be performed, reflecting the way 
in which program/project costs, schedule, technical, 
and risk data are to be accumulated, summarized, 
and reported.
WBS Model: A WBS model describes a system that 
consists of end products and their subsystems (which 
perform the operational functions of the system), the 
supporting or enabling products, and any other work 
products (plans, baselines) required for the develop -
ment of the system.
Workflow Diagram: A scheduling chart that 
shows activities, dependencies among activities, 
and milestones.197
Appendix C:  Ho w to Write a Good Requirement— 
Checklist
C.1 Use of Correct Terms
 Shall = requirement
 Will = facts or declaration of purpose
 Should = goal
C.2 Editorial Checklist
Personnel Requirement
 The requirement is in the form “responsible party 
shall perform such and such.” In other words, use the active, rather than the passive voice. A require -
ment should state who shall (do, perform, provide, weigh, or other verb) followed by a description of what should be performed.
Product Requirement
 The requirement is in the form “product ABC shall XYZ.” A requirement should state “The product shall” (do, perform, provide, weigh, or other verb) followed by a description of what should be done.
 The requirement uses consistent terminology to refer to the product and its lower-level entities.
 Complete with tolerances for qualitative/perfor -
mance values (e.g., less than, greater than or equal to, plus or minus, 3 sigma root sum squares).
 Is the requirement free of implementation? (Requirements should state WHAT is needed, NOT HOW to provide it; i.e., state the problem not the solution. Ask, “Why do you need the requirement?” The answer may point to the real requirement.)
 Free of descriptions of operations? (Is this a need the product should satisfy or an activity involv -
ing the product? Sentences like “The operator shall…” are almost always operational statements not requirements.)
Example Product Requirements
 The system shall operate at a power level of…
 The software shall acquire data from the…
 The structure shall withstand loads of…
 The hardware shall have a mass of…
C.3 General Goodness Checklist
 The requirement is grammatically correct.
 The requirement is free of typos, misspellings, and punctuation errors.
 The requirement complies with the project’s tem -
plate and style rules.
 The requirement is stated positively (as opposed to negatively, i.e., “shall not”).
 The use of “To Be Determined” (TBD) values should be minimized. It is better to use a best 198
NASA SYSTEMS ENGINEERING HANDBOOKAppendix C: How to Write a Good Requirement— Checklist
estimate for a value and mark it “To Be Resolved” 
(TBR) with the rationale along with what should 
be done to eliminate the TBR, who is responsi -
ble for its elimination, and by when it should be 
eliminated.
 The requirement is accompanied by an intel -
ligible rationale, including any assumptions. 
Can you validate (concur with) the assump -
tions? Assumptions should be confirmed before 
baselining.
 The requirement is located in the proper section of 
the document (e.g., not in an appendix).
C.4 Requirements Validation 
Checklist
Clarity
 Are the requirements clear and unambiguous? 
(Are all aspects of the requirement understand -
able and not subject to misinterpretation? Is the 
requirement free from indefinite pronouns (this, 
these) and ambiguous terms (e.g., “as appropri -
ate,” “etc.,” “and/or,” “but not limited to”)?)
 Are the requirements concise and simple?
 Do the requirements express only one thought per 
requirement statement, a stand-alone statement as 
opposed to multiple requirements in a single state -
ment, or a paragraph that contains both require -
ments and rationale?
 Does the requirement statement have one subject 
and one predicate?
Completeness
 Are requirements stated as completely as possible? 
Have all incomplete requirements been captured as TBDs or TBRs and a complete listing of them 
maintained with the requirements?
 Are any requirements missing? For example, 
have any of the following requirements areas 
been overlooked: functional, performance, inter -
face, environment (development, manufacturing, 
test, transport, storage, and operations), facility 
(manufacturing, test, storage, and operations), 
transportation (among areas for manufacturing, 
assembling, delivery points, within storage facil -
ities, loading), training, personnel, operability, 
safety, security, appearance and physical charac -
teristics, and design.
 Have all assumptions been explicitly stated?
Compliance
 Are all requirements at the correct level (e.g., sys -
tem, segment, element, subsystem)?
 Are requirements free of implementation specif -
ics? (Requirements should state what is needed, 
not how to provide it.)
 Are requirements free of descriptions of opera -
tions? (Don’t mix operation with requirements: 
update the ConOps instead.)
 Are requirements free of personnel or task assign -
ments? (Don’t mix personnel/task with product 
requirements: update the SOW or Task Order 
instead.)
Consistency
 Are the requirements stated consistently without 
contradicting themselves or the requirements of 
related systems?
 Is the terminology consistent with the user and 
sponsor’s terminology? With the project glossary?199
 Is the terminology consistently used throughout 
the document? Are the key terms included in the 
project’s glossary?
 Are all requirements needed? Is each requirement 
necessary to meet the parent requirement? Is each 
requirement a needed function or characteristic?

instead.)
requirement a needed function or characteristic? 
Distinguish between needs and wants. If it is not 
necessary, it is not a requirement. Ask, “What is 
the worst that could happen if the requirement 
was not included?”
 Are all requirements (functions, structures, and 
constraints) bidirectionally traceable to high -
er-level requirements or mission or system-of-in -
terest scope (i.e., need(s), goals, objectives, 
constraints, or concept of operations)?
 Is each requirement stated in such a manner that it 
can be uniquely referenced (e.g., each requirement 
is uniquely numbered) in subordinate documents?
Correctness
 Is each requirement correct?
 Is each stated assumption correct? Assumptions 
should be confirmed before the document can be 
baselined.
 Are the requirements technically feasible?
Functionality
 Are all described functions necessary and together 
sufficient to meet mission and system goals and 
objectives?
 Are all required performance specifications and 
margins listed (e.g., consider timing, throughput, 
storage size, latency, accuracy and precision)? Is each performance requirement realistic?
 Are the tolerances overly tight? Are the tolerances 
defendable and cost-effective? Ask, “What is the 
worst thing that could happen if the tolerance was 
doubled or tripled?”
Interfaces
 Are all external interfaces clearly defined?
 Are all internal interfaces clearly defined?
 Are all interfaces necessary, sufficient, and consis -
tent with each other?
Maintainability
 Have the requirements for maintainability of the 
system been specified in a measurable, verifiable 
manner?
 Are requirements written so that ripple effects 
from changes are minimized (i.e., requirements 
are as weakly coupled as possible)?
Reliability
 Are clearly defined, measurable, and verifiable 
reliability requirements specified?
 Are there error detection, reporting, handling, 
and recovery requirements?
 Are undesired events (e.g., single-event upset, data 
loss or scrambling, operator error) considered and 
their required responses specified?
 Have assumptions about the intended sequence 
of functions been stated? Are these sequences 
required?
 Do these requirements adequately address the 
survivability after a software or hardware fault of 200
the system from the point of view of hardware, 
software, operations, personnel and procedures?
Verifiability/Testability
 Can the system be tested, demonstrated, 
inspected, or analyzed to show that it satisfies 
requirements? Can this be done at the level of the 
system at which the requirement is stated? Does 
a means exist to measure the accomplishment of 
the requirement and verify compliance? Can the 
criteria for verification be stated?
 Are the requirements stated precisely to facilitate 
specification of system test success criteria and 
requirements? Are the requirements free of unverifiable terms 
(e.g., flexible, easy, sufficient, safe, ad hoc, ade -
quate, accommodate, user-friendly, usable, when 
required, if required, appropriate, fast, portable, 
light-weight, small, large, maximize, minimize, 
sufficient, robust, quickly, easily, clearly, other 
“ly” words, other “ize” words)?
Data Usage
 Where applicable, are “don’t care” conditions 
truly “don’t care”? (“Don’t care” values identify 
cases when the value of a condition or flag is irrel -
evant, even though the value may be important 
for other cases.) Are “don’t care” conditions values 
explicitly stated? (Correct identification of “don’t 
care” values may improve a design’s portability.)201
Appendix D: Requirements Verification Matrix
When developing requirements, it is important to 
identify an approach for verifying the requirements. This appendix provides an example matrix that defines how all the requirements are verified. Only “shall” requirements should be included in these matrices. The matrix should identify each “shall” by unique identifier and be definitive as to the source, i.e., document from which the requirement is taken. This matrix could be divided into multiple matri -
ces (e.g., one for each requirements document) to delineate sources of requirements depending on the project. The example is shown to provide suggested guidelines for the minimum information that should be included in the verification matrix.
NOTE: 
See Appendix I  for an outline of the 
Verification and Validation Plan. The matrix shown 
here ( TABLE D-1 ) is Appendix C in that outline.202
NASA SYSTEMS ENGINEERING HANDBOOKAppendix D: Requirements Verification MatrixTABLE D-1 Requirements Verification Matrix 
Require -
ment No.Document Para -
graphShall 
State -
mentVerifi -
cation 
Success 
CriteriaVerifi -
cation 
MethodFacility or 
LabPhaseaAccep -
tance 
Require -
ment?Preflight 
Accep -
tance?Perform -
ing Orga -
nizationResults
Unique iden -
tifier or each 
requirementDocument 
number the 
requirement 
is contained 
withinParagraph 
number of the 
requirementText (within 
reason) of the 
requirement, 
i.e., the 
“shall”Success 
criteria for the 
requirementVerification 
method 
for the 
(analysis, 
inspection, 
demonstration, 
test)Facility or 
laboratory 
used to per -
form the ver -
ification and 
validation.Phase in 
which the 
verification 
and valida -
tion will be 
performed.Indicate 
whether this 
is also ver -
ified during 
initial accep -
tance testing 
of each unit.Indicate 
any pre-flight 
or recurring 
acceptance 
testing of 
each unitOrganization 
responsible 
for per -
forming the 
verificationIndicate 
documents 
that contain 
the objective 
evidence that 
was satisfied
P-1 xxx 3.2.1.1 
Capability: 
Support 
Uplinked Data 
(LDR)System X 
shall provide 
a max. 
ground-to-
station uplink 
of…1. System 
X locks to 
forward link 
at the min 
and max 
data rate 
tolerances
2. System 
X locks to 
the forward 
link at the 
min and max 
operating 
frequency 
tolerancesTest xxx 5 Yes No xxx TPS  
xxxx
P-i xxx Other 
paragraphsOther “shalls” 
in PTRSOther criteria xxx xxx xxx Yes/No Yes/No xxx Memo xxx
S-i or other 
unique 
designatorxxxxx (other 
specs, ICDs, 
etc.)Other 
paragraphsOther 
“shalls” in 
etc.Other criteria xxx xxx xxx Yes/No Yes/No xxx Report xxx
a  Phases defined as: (1) Pre-Declared Development, (2) Formal Box-Level Functional, (3) Formal Box-Level Environmental, (4) Formal System-Level Environmental, (5) 
Formal System-Level Functional, (6) Formal End-to-End Functional, (7) Integrated Vehicle Functional,  
(8) On-Orbit Functional  .203
Appendix E:  C reating the Validation Plan with a 
Validation Requirements Matrix
NOTE:  See Appendix I  for an outline of the 
here ( TABLE E-1 ) is Appendix D  in that outline.
identify a validation approach for how additional val -
idation evaluation, testing, analysis, or other demon -
strations will be performed to ensure customer/sponsor satisfaction.
There are a number of sources to draw from for creat -
ing the validation plan:
• ConOps
• Stakeholder/customer needs, goals, and objectives 
documentation
• Rationale statements for requirements and in ver -
ification requirements
• Lessons learned database
• System architecture modeling
• Test-as-you-fly design goals and constraints
• SEMP, HSIP, V&V plansValidation products can take the form of a wide range of deliverables, including:
• Stakeholder evaluation and feedback
• Peer reviews
• Physical models of all fidelities
• Simulations
• Virtual modeling
• Tests
• Fit-checks
• Procedure dry-runs
• Integration activities (to inform on-orbit mainte -
nance procedures)
• Phase-level review solicitation and feedback
Particular attention should be paid to the planning 
for life cycle phase since early validation can have a 
profound impact on the design and cost in the later life cycle phases.
TABLE E-1 shows an example validation matrix.204
NASA SYSTEMS ENGINEERING HANDBOOKAppendix E: Creating the Validation Plan with a Validation Requirements Matrix
TABLE E-1 Validation Requirements Matrix
Validation 
Product #Activity Objective Validation 
MethodFacility 
or LabPhase Performing 
OrganizationResults
Unique 
identifier for 
validation 
productDescribe 
evaluation 
by the 
customer/
sponsor 
that will be 
performedWhat is to be 
accomplished 
by the 
customer/
sponsor 
evaluationValidation 
method 
for the 
demonstra -
tion, or test)Facility or 
used to 
perform 
the 
validationPhase in 
which the 
verification/
will be 
performedaOrganization 
responsible for 
coordinating 
the validation 
activityIndicate the 
objective 
evidence 
that 
activity 
occurred
1 Customer/
sponsor 
will 
evaluate 
the 
candidate 
displays1. Ensure 
legibility is 
acceptable 2.

Unique 
by the 
customer/
sponsor 
by the 
customer/
sponsor 
method 
for the 
used to 
perform 
the 
which the 
will be 
objective 
evidence 
that 
activity 
occurred
sponsor 
will 
evaluate 
the 
candidate 
acceptable 2. 
Ensure overall 
appearance is 
acceptableTest xxx Phase A xxx TPS 123456
a .  Example: (1) during product selection process, (2) prior to final product selection (if COTS) or prior to PDR, (3) prior to CDR, 
(4) during box-level functional, (5) during system-level functional, (6) during end-to-end functional, (7) during integrated vehicle 
functional, (8) during on-orbit functional  .205
Appendix F: Functional, Timing, and State Analysis
This appendix was removed. For additional guidance 
on functional flow block diagrams, requirements allo -
cation sheets/models, N-squared diagrams, timing analysis, and state analysis refer to Appendix F in the NASA Expanded Guidance for Systems Engineering at 
https://nen.nasa.gov/web/se/doc-repository .206
Appendix G: Technology Assessment/Insertion
G.1 Introduction, Purpose,  
and Scope
In 2014, the Headquarters Office of Chief Engineer 
and Office of Chief Technologist conducted an Agency-wide study on Technical Readiness Level (TRL) usage and Technology Readiness Assessment (TRA) implementation. Numerous findings, observa -
tions, and recommendations were identified, as was a wealth of new guidance, best practices, and clarifica -
tions on how to interpret TRL and perform TRAs. These are presently being collected into a NASA TRA Handbook (in work), which will replace this appendix. In the interim, contact HQ/Steven Hirshorn on any specific questions on interpretation and application of TRL/TRA. Although the information contained in this appendix may change, it does provide some infor -
mation until the TRA Handbook can be completed.
Agency programs and projects frequently require 
the development and infusion of new technologi -
cal advances to meet mission goals, objectives, and resulting requirements. Sometimes the new techno -
logical advancement being infused is actually a heri -
tage system that is being incorporated into a different architecture and operated in a different environment from that for which it was originally designed. It is important to recognize that the adaptation of heritage systems frequently requires technological advance -
ment. Failure to account for this requirement can result in key steps of the development process being given short shrift—often to the detriment of the program/project. In both contexts of technological advancement (new and adapted heritage), infusion is a complex process that is often dealt with in an ad hoc manner differing greatly from project to project with varying degrees of success.
Technology infusion frequently results in schedule 
slips, cost overruns, and occasionally even in cancel -
lations or failures. In post mortem, the root cause of such events is often attributed to “inadequate defi -
nition of requirements.” If such is indeed the root cause, then correcting the situation is simply a matter of defining better requirements, but this may not be the case—at least not totally.
In fact, there are many contributors to schedule 
slip, cost overrun, and project cancellation and fail -
ure—among them lack of adequate requirements definition. The case can be made that most of these contributors are related to the degree of uncertainty at the outset of the project and that a dominant factor in the degree of uncertainty is the lack of understand -
ing of the maturity of the technology required to bring the project to fruition and a concomitant lack of understanding of the cost and schedule reserves required to advance the technology from its present state to a point where it can be qualified and suc -
cessfully infused with a high degree of confidence. Although this uncertainty cannot be eliminated, it can be substantially reduced through the early appli -
cation of good systems engineering practices focused on understanding the technological requirements; the maturity of the required technology; and the technological advancement required to meet pro -
gram/project goals, objectives, and requirements.207
NASA SYSTEMS ENGINEERING HANDBOOKAppendix G: Technology Assessment/Insertion
A number of processes can be used to develop the 
appropriate level of understanding required for successful technology insertion. The intent of this appendix is to describe a systematic process that can be used as an example of how to apply standard systems engineering practices to perform a compre -
hensive Technology Assessment (TA). The TA com -
prises two parts, a Technology Maturity Assessment (TMA) and an Advancement Degree of Difficulty Assessment (AD
2). The process begins with the TMA 
which is used to determine technological maturity via NASA’s Technology Readiness Level (TRL) scale. It then proceeds to develop an understanding of what is required to advance the level of maturity through the AD
2. It is necessary to conduct TAs at various 
stages throughout a program/project to provide the Key Decision Point (KDP) products required for transition between phases. (See 
TABLE G.1-1 .)
The initial TMA provides the baseline maturity of the system’s required technologies at program/project outset and allows monitoring progress throughout development. The final TMA is performed just prior to the Preliminary Design Review (PDR). It forms the basis for the Technology Readiness Assessment Report (TRAR), which documents the maturity of the technological advancement required by the systems, subsystems, and components demonstrated through test and analysis. The initial AD
2 provides the 
material necessary to develop preliminary cost and to schedule plans and preliminary risk assessments. In subsequent assessments, the information is used to build the Technology Development Plan and in the process, identify alternative paths, fallback positions, and performance descope options. The information is also vital to preparing milestones and metrics for 
subsequent Earned Value Management  (EVM).
The TMA is performed against the hierarchical breakdown of the hardware and software products of the program/project PBS to achieve a systematic, overall understanding at the system, subsystem, and component levels. (See 
FIGURE G.1-1 .)TABLE G.1-1 Products Provided by the TA as a Function of Program/Project Phase
Gate Product
KDP A:  Transition from Requires an assessment of potential technology needs versus current and planned 
Pre-Phase A to Phase A technology readiness levels, as well as potential opportunities to use commercial, 
academic, and other government agency sources of technology. Included as part of the draft integrated baseline. Technology Development Plan is baselined that identifies technologies to be developed, heritage systems to be modified, alternative paths to be pursued, fallback positions and corresponding performance descopes, milestones, metrics, and key decision points. Initial Technology Readiness Assessment (TRA) is available.
KDP B:  Transition from Technology Development Plan and Technology Readiness Assessment (TRA) are updated. 
Phase A to Phase B Incorporated in the preliminary project plan.
KDP C:  Transition from Requires a TRAR demonstrating that all systems, subsystems, and components have 
Phase B to Phase C/D achieved a level of technological maturity with demonstrated evidence of qualification in a relevant environment.
Source: NPR 7120  .5 .
G.2 Inputs/Entry Criteria
It is extremely important that a TA process be defined 
at the beginning of the program/project and that it be performed at the earliest possible stage (concept development) and throughout the program/proj -
ect through PDR. Inputs to the process will vary in level of detail according to the phase of the program/project, and even though there is a lack of detail in Pre-Phase A, the TA will drive out the major critical 208
technological advancements required. Therefore, at 
the beginning of Pre-Phase A, the following should be provided:
• Refinement of TRL definitions.
• Definition of AD2.
• Definition of terms to be used in the assessment process.
• Establishment of meaningful evaluation criteria and metrics that will allow for clear identification of gaps and shortfalls in performance.
• Establishment of the TA team.
• Establishment of an independent TA review team..1: Integ MPS
.2: LH System.3: O2 F luid Sys.
.4: Pressure &
Pneumatic Sys.
.5: Umbilicals & 
Disconnect Crew Launch
Vehicle1.3
Launch
Vehicle1.3.8
First Stage1.3.8.1
Upper Stage1.3.8.2
Upper Stage
Engine1.3.8.3...
MPS1.3.8.2.4...
US R CS1.3.8.2.5
FS R CS1.3.8.2.6
TVCS1.3.8.2.7
Avionics1.3.8.2.8
Software1.3.8.2.9
...Integrated
Test H/W1.3.8.2.10...
.1: Integ RCS
.2: Integ Energy
Support.1: Integ RCS .1: Integ TVCS
.2: Actuator
.3: Hydraulic
Power
.4: APU.1: Integ Avionic s
.2: C&DH System
.3: GN&C H/W
.4: Radio Frequency
System
.5: EPS
.6: Electrical Integration
.7: Develop Flight Instrument
.8: Sensor & Instrument System
.9: EGSE.10: Integ CLV Avionics System

Launch
Power
System
.5: EPS
Element Testing.11: Flight Safe ty Sys tem.1: Integ S/W
System
.2: Flight S/W.
1: MPTA
.2: GVT.3: STA.4: US for DTF-1.5: US for VTF-2
.6: US for RRF-3
.7: Struc. Therma l
Component Test
FIGURE G.1-1  P BS Example
G.3 How to Do Technology 
The technology assessment process makes use of basic 
systems engineering principles and processes. As mentioned previously, it is structured to occur within 
the framework of the Product Breakdown Structure 
(PBS) to facilitate incorporation of the results. Using the PBS as a framework has a twofold benefit—it breaks the “problem” down into systems, subsys -
tems, and components that can be more accurately assessed; and it provides the results of the assessment 
in a format that can be readily used in the generation 209
of program costs and schedules. It can also be highly 
beneficial in providing milestones and metrics for progress tracking using EVM. As discussed above, it is a two-step process comprised of (1) the determina -
tion of the current technological maturity in terms of TRLs and (2) the determination of the difficulty associated with moving a technology from one TRL to the next through the use of the AD
2.
Conceptual Level ActivitiesThe overall process is iterative, starting at the concep -
tual level during program Formulation, establishing the initial identification of critical technologies, and establishing the preliminary cost, schedule, and risk mitigation plans. Continuing on into Phase A, the process is used to establish the baseline maturity, the Technology Development Plan, and the associated costs and schedule. The final TA consists only of the TMA and is used to develop the TRAR, which val -
idates that all elements are at the requisite maturity level. (See 
FIGURE G.3-1 .)
Identify systems, sub-
systems, and components
per hierarchical product
breakdown of the WBS Assign TRL to subsystems
based on lowest TRL of
components and TRL 
state of integration Assign TRL to all
components based on
assessment of maturity
Assign TRL to systems
subsystems and TRL 
state of integration Identify all components,
subsystems, and systems
that are at lower TRLs
than required by programBaseline technology
maturity assessment
Perform AD2 on all
components, subsystems,
and systems that are below
requisite maturity level
Technology Development Plan
Cost Plan
Schedule Plan
Risk Assessment
FIGURE G.3-1  Te chnology Assessment ProcessE
ven at the conceptual level, it is important to use 
the formalism of a PBS to avoid allowing important technologies to slip through the cracks. Because of the preliminary nature of the concept, the systems, subsystems, and components will be defined at a level that will not permit detailed assessments to be made. The process of performing the assessment, however, is the same as that used for subsequent, more detailed steps that occur later in the program/project where systems are defined in greater detail.
Architectural Studies
Once the concept has been formulated and the ini -
tial identification of critical technologies made, it is 210
necessary to perform detailed architecture studies 
with the Technology Assessment Process intimately 
interwoven. (See FIGURE G.3-2. )
Requir e-
ments
TRL/AD2 AssessmentArchitectural
Studies
Technology Maturation ConceptsSystem
Design
FIGURE G.3-2 Architectural Studies and Technology 
Development
The purpose of the architecture studies is to refine 
end-item system design to meet the overall scientific 
requirements of the mission. It is imperative that 
there be a continuous relationship between architec -
tural studies and maturing technology advances. The 
architectural studies should incorporate the results of 
the technology maturation, planning for alternative 
paths and identifying new areas required for devel -
opment as the architecture is refined. Similarly, it 
is incumbent upon the technology maturation pro -
cess to identify requirements that are not feasible 
and development routes that are not fruitful and to 
transmit that information to the architecture studies 
in a timely manner. It is also incumbent upon the 
architecture studies to provide feedback to the tech -
nology development process relative to changes in 
requirements. Particular attention should be given 
to “heritage” systems in that they are often used in 
architectures and environments different from those 
in which they were designed to operate.
G.4 Establishing TRLs
A Technology Readiness Level (TRL) is, at its most 
basic, a description of the performance history of a 
given system, subsystem, or component relative to 
a set of levels first described at NASA HQ in the 1980s. The TRL essentially describes the state of a 
given technology and provides a baseline from which 
maturity is gauged and advancement defined. (See 
FIGURE G.4-1 .)
Programs are often undertaken without fully under -
standing either the maturity of key technologies 
or what is needed to develop them to the required 
level. It is impossible to understand the magnitude and 
scope of a development program without having a clear 
understanding of the baseline technological maturity of 
all elements of the system. Establishing the TRL is a 
vital first step on the way to a successful program. A 
frequent misconception is that in practice, it is too 
difficult to determine TRLs and that when you do, 
it is not meaningful. On the contrary, identifying 
TRLs can be a straightforward systems engineering 
process of determining what was demonstrated and 
under what conditions it was demonstrated.
Terminology
At first glance, the TRL descriptions in FIGURE G.4-1  
appear to be straightforward. It is in the process of 
trying to assign levels that problems arise. A primary 
cause of difficulty is in terminology; e.g., everyone 
knows what a breadboard is, but not everyone has 
the same definition. Also, what is a “relevant envi -
ronment?” What is relevant to one application may 
or may not be relevant to another. Many of these 
terms originated in various branches of engineering 
and had, at the time, very specific meanings to that 
particular field. They have since become commonly 
used throughout the engineering field and often 
acquire differences in meaning from discipline to 
discipline, some differences subtle, some not so sub -
tle. “Breadboard,” for example, comes from electrical 
engineering where the original use referred to check -
ing out the functional design of an electrical circuit 
by populating a “breadboard” with components to 
verify that the design operated as anticipated. Other 
terms come from mechanical engineering, referring 211
primarily to units that are subjected to different levels 
of stress under testing, e.g., qualification, protoflight, and flight units. The first step in developing a uni -
form TRL assessment (see 
FIGURE G.4-2 ) is to define 
the terms used. It is extremely important to develop and use a consistent set of definitions over the course of the program/project.TRL 1          Basic principles observed and reportedTRL 2         Technology concept and/or application form ulated
  __TRL 3 Analytical and experimental critical function and/or
 __ characteristic proof-of-conceptTRL 4 Component and/or breadboard validation in laboratory   __ environment TRL 5 Component and/or breadboard validation in relevant  __ environmentTRL 6 System/subsystem model or prototype demonstration  __  in a relevant environment (ground or space)TRL 7 
System prototype demonstration in a target/space environment
  __TRL 8 Actual system completed and “flight qualified” through
test and demonstration (ground or flight)” 
  __ TRL 9 Actual system “flight proven” thr ough su cces sful
  __ mission operationsSystem test, launch, 
and operations
System/subsystem
development
Technology
demonstration
Research to prove
feasibility
Basic technology
research
FIGURE G.4-1  Tec hnology Readiness Levels
Jud
gment Calls
Having established a common set of terminology, it 
is necessary to proceed to the next step: quantifying “judgment calls” on the basis of past experience. Even with clear definitions, judgment calls will be required wh
en it comes time to assess just how similar a given 
element is relative to what is needed (i.e., is it close enough to a prototype to be considered a proto -
type, or is it more like an engineering breadboard?). Describing what has been done in terms of form, fit, and function provides a means of quantifying an element based on its design intent and subsequent performance. The current definitions for software TRLs are contained in NPR 7123.1, NASA Systems Engineering Processes and Requirements.212
Assessment Team

research
Jud
A third critical element of any assessment relates to the question of who is in the best position to make judgment calls relative to the status of the technol -
ogy in question. For this step, it is extremely import -
ant to have a well-balanced, experienced assessment team. Team members do not necessarily have to be discipline experts. The primary expertise required for a TRL assessment is that the systems engineer/user understands the current state of the art in applica -
tions. User considerations are evaluated by HFE per -
sonnel who understand the challenges of technology insertions at various stages of the product life cycle. Having established a set of definitions, defined a pro -
cess for quantifying judgment calls, and assembled an expert assessment team, the process primarily consists of asking the right questions. The flowchart depicted in 
FIGURE G.4-2  demonstrates the questions to ask to 
determine TRL at any level in the assessment.Has an identical unit been successfully
operated/ launched in i dentical
configu ration/environment?
Has an identical unit in a different configuration/
system architecture been successfully operated
in space or the target environment or launched?
If so, then this initially drops to TRL 5 until
differences are evaulated.
Has an identical unit been flight qualified but
not yet operated in space or the target
environment or launched?
Has a prototype unit (or one similar enough to be
considered a prototype) been successfully operated
in space or the  target environment or launched?
Has a prototype unit (or one similar enough 
to be considered a prototype) been 
demonstrated in a relevant environment?
Has a breadboard unit been demonstrated in 
a relevant environment?
a laboratory environment?
Has analytical and experimental
proof-of-concept been demonstrated?
Has concept or application
been formulated?
Have basic principles been observed
and reported?
RETHINK POSITION REGARDING
THIS TECHNOLOGY!NONONONONONONONONONOTRL 9YES
TRL 5YES
TRL 2YES
TRL 1YESTRL 3YESTRL 4YESTRL 5YESTRL 6YESTRL 7YESTRL 8YES
FIGURE G.4-2  TM A Thought ProcessH
eritage Systems
Note the second box particularly refers to heritage 
systems. If the architecture and the environment have changed, then the TRL drops to TRL 5—at least initially. Additional testing may need to be done for heritage systems for the new use or new environ -
ment. If in subsequent analysis the new environment is sufficiently close to the old environment or the new architecture sufficiently close to the old architecture, then the resulting evaluation could be TRL 6 or 7, but the most important thing to realize is that it is no longer at TRL 9. Applying this process at the system level and then proceeding to lower levels of subsystem and component identifies those elements that require development and sets the stage for the subsequent phase, determining the AD
2.213
Formal Process for Determining TRLs
A method for formalizing this process is shown in 
FIGURE G.4-3 . Here, the process has been set up as a 
table: the rows identify the systems, subsystems, and 
components that are under assessment. The columns 
identify the categories that will be used to determine 
the TRL; i.e., what units have been built, to what 
scale, and in what environment have they been tested. 
Answers to these questions determine the TRL of an 
item under consideration. The TRL of the system is 
determined by the lowest TRL present in the system; 
i.e., a system is at TRL 2 if any single element in the system is at TRL 2. The problem of multiple ele -
ments being at low TRLs is dealt with in the AD2 
process. Note that the issue of integration affects the 
TRL of every system, subsystem, and component. All 
of the elements can be at a higher TRL, but if they 
have never been integrated as a unit, the TRL will 
be lower for the unit. How much lower depends on 
the complexity of the integration. The assessed com -
plexity depends upon the combined judgment of the 
engineers. It is important to have a good cross-section 
of senior people sitting in judgment.
 Red = Below TRL 3
 Yellow = TRL 3, 4 & 5
 Green = TRL 6 and above
 White = Unknown
 X = Exists
ConceptDemonstration Units Environment Unit Description
Overall TRLBreadboard
Brassboard
Developmental Model
Protogype
Flight Qualified
Laboratory Environment
Relevant Environment
Space Environment
Space Launch Operation
Form
Fit
Function
Appropriatae Scale
1.0 System
1.1 Subsystem X
1.1.1 Mechanical Components
1.1.2 Mechanical Systems
1.1.3 Electrical Components X X X X X
1.1.4 Electrical Systems
1.1.5 Control Systems
1.1.6 Thermal Systems X X X
1.1.7 Fluid Systems X
1.1.8 Optical Systems
1.1.9 Electro-Optical Systems
1.1.10 Software Systems
1.1.11 Mechanisms X
1.1.12 Integration
1.2 Subsystem Y
1.2.1 Mechanical Components
FIGURE G.4-3 TRL Assessment Matrix214
Appendix H: Integration Plan Outline
H.1 Purpose
The integration plan defines the integration and ver -
ification strategies for a project interface with the 
system design and decomposition into the lower-level elements.
1 The integration plan is structured to bring 
the elements together to assemble each subsystem and to bring all of the subsystems together to assem -
ble the system/product. The primary purposes of the integration plan are: (1) to describe this coordinated integration effort that supports the implementation strategy, (2) to describe for the participants what needs to be done in each integration step, and (3) to identify the required resources and when and where they will be needed.
H.2 Questions/Checklist
• Does the integration plan include and cover inte -
gration of all of the components and subsystems of the project, either developed or purchased?
• Does the integration plan account for all exter -
nal systems to be integrated with the system (for example, communications networks, field equip -
ment, other complete systems owned by the gov -
ernment or owned by other government agencies)?
• Does the integration plan fully support the imple -
mentation strategy, for example, when and where the subsystems and system are to be used?
1  The material in this appendix is adapted from Federal 
Highway Administration and CalTrans, Systems Engineering 
Guidebook for ITS, Version 2  0 .• Does the integration plan mesh with the verifica -
tion plan?
• For each integration step, does the integration plan define what components and subsystems are to be integrated?
• For each integration step, does the integration plan identify all the needed participants and define what their roles and responsibilities are?
• Does the integration plan establish the sequence and schedule for every integration step?
• Does the integration plan spell out how integra -
tion problems are to be documented and resolved?
H.3 Integration Plan Contents
Title PageThe title page should follow the NASA procedures or style guide. At a minimum, it should contain the follow -
ing information:
• INTEGRATION PLAN FOR THE [insert name 
of project]  AND [insert name of organization]
• Contract number
• Date that the document was formally approved
• The organization responsible for preparing the document215
NASA SYSTEMS ENGINEERING HANDBOOKAppendix H: Integration Plan Outline
• Internal document control number, if available
• Revision version and date issued
1.0 Purpose of Document
This section gives a brief statement of the purpose of this 
document. It is the plan for integrating the components 
and subsystems of the project prior to verification.
2.0 Scope of Project
This section gives a brief description of the planned proj -
ect and the purpose of the system to be built. Special 
emphasis is placed on the project’s deployment complex -
ities and challenges.
3.0 Integration Strategy
This section tells the reader what the high-level plan for 
integration is and, most importantly, why the integra -
tion plan is structured the way it is. The integration plan 
is subject to several, sometimes conflicting, constraints. 
Also, it is one part of the larger process of build, inte -
grate, verify, and deploy, all of which should be syn -
chronized to support the same project strategy. So, for 
even a moderately complex project, the integration strat -
egy, which is based on a clear and concise statement of 
the project’s goals and objectives, is described here at a 
high but all-inclusive level. It may also be necessary to 
describe the analysis of alternative strategies to make it 
clear why this particular strategy was selected.
The same strategy is the basis for the build plan, the 
verification plan, and the deployment plan. This section 
covers and describes each step in the integration process. 
It describes what components are integrated at each step 
and gives a general idea of what threads of the opera -

tional capabilities (requirements) are covered. It ties the 
plan to the previously identified goals and objectives so 
the stakeholders can understand the rationale for each 
integration step. This summary-level description also 
defines the schedule for all the integration efforts.4.0 Phase 1 Integration
This and the following sections define and explain each 
step in the integration process. The intent here is to iden -
tify all the needed participants and to describe to them 
what they have to do. In general, the description of each 
integration step should identify the following:
• The location of the activities.
• The project-developed equipment and software prod -
ucts to be integrated. Initially this is just a high-level 
list, but eventually the list should be exact and com -
plete, showing part numbers and quantity.
• Any support equipment (special software, test hard -
ware, software stubs, and drivers to simulate yet-to-
be-integrated software components, external systems) 
needed for this integration step. The same support 
equipment is most likely needed for the subsequent 
verification step.
• All integration activities that need to be performed 
after installation, including integration with onsite 
systems and external systems at other sites.
• A description of the verification activities, as defined 
in the applicable verification plan, that occur after 
this integration step.
• The responsible parties for each activity in the inte -
gration step.
• The schedule for each activity.
5.0  Multiple Phase Integration Steps  
(1 or N steps)
This and any needed additional sections follow the 
format for Section 3.0. Each covers each step in a 
multiple-step integration effort.216
Appendix I: Verification and Validation Plan Outline
Sample Outline
The Verification and Validation (V&V) Plan needs 
to be baselined after the comments from PDR are incorporated. In this annotated outline, the use of the term “system” is indicative of the entire scope for which this plan is developed. This may be an entire spacecraft, just the avionics system, or a card within the avionics system. Likewise, the terms “end item,” “subsystem,” or “element” are meant to imply the lower-level products that, when integrated together, will produce the “system.” The general term “end item” is used to encompass activities regardless of whether the end item is a hardware or software element.
The various sections are intended to move from the 
high-level generic descriptions to the more detailed. The sections also flow from the lower-level items in the product layer to larger and larger assemblies and to the completely integrated system. The sections also describe how that system may be integrated and fur -
ther verified/validated with its externally interfacing elements. This progression will help build a complete understanding of the overall plans for verification and validation.
1.0 Introduction
1.1 Purpose and Scope
This section states the purpose of this Verification and Validation Plan and the scope (i.e., systems) to which it applies. The purpose of the V&V Plan is to identify the activities that will establish compliance with the requirements (verification) and to establish that the sys -
tem will meet the customers’ expectations (validation).
1.2  Responsibility and Change 
Authority
This section will identify who has responsibility for the 
maintenance of this plan and who or what board has the authority to approve any changes to it.
1.3 Definitions
This section will define any key terms used in the plan. The section may include the definitions of verification, validation, analysis, test, demonstration, and test. See 
appendix B  of this handbook for definitions of these and 
other terms that might be used.
2.0 Applicable and Reference 
Documents
2.1 Applicable Documents
These are the documents that may impose additional 
requirements or from which some of the requirements have been taken.
2.2 Reference Documents
These are the documents that are referred to within the V&V Plan that do not impose requirements, but which may have additional useful information.
2.3 Order of Precedence
This section identifies which documents take precedence whenever there are conflicting requirements.217
NASA SYSTEMS ENGINEERING HANDBOOKAppendix I: Verification and Validation Plan Outline
3.0 System Description
3.1 System Requirements Flowdown
This section describes where the requirements for this 
system come from and how they are flowed down to 
subsystems and lower-level elements. It should also 
indicate what method will be used to perform the flow -
down and bidirectional traceability of the requirements: 
spreadsheet, model, or other means. It can point to the 
file, document, or spreadsheet that captures the actual 
requirements flowdown.
3.2 System Architecture
This section describes the system that is within the scope 
of this V&V Plan. The description should be enough so 
that the V&V activities will have the proper context and 
be understandable.
3.3 End Item Architectures
This section describes each of the major end items (sub -
systems, elements, units, modules, etc.) that when inte -
grated together, will form the overall system that is the 
scope of this V&V Plan.
3.3.1 System End Item A
This section describes the first major end item/subsystem 
in more detail so that the V&V activities have context 
and are understandable.
3.3.n System End Item n
Each end item/subsystem is separately described in a sim -
ilar manner as above.
3.4 Ground Support Equipment
This section describes any major ground-support equip -
ment that will be used during the V&V activities. This 
may include carts for supplying power or fuel, special test 
fixtures, lifting aids, simulators, or other type of support.
3.5 Other Architecture Descriptions
This section describes any other items that are import -
ant for the V&V activities but which are not included in the sections above. This may be an existing control 
center, training facility, or other support.
4.0 Verification and Validation 
Process
This section describes the process that will be used to per -
form verification and validation.
4.1  Verification and Validation 
Management Responsibilities
This section describes the responsibilities of key players 
in the V&V activities. It may include identification and 
duty description for test directors/conductors, managers, 
facility owners, boards, and other key stakeholders.
4.2 Verification Methods
This section defines and describes the methods that will 
be used during the verification activities.
4.2.1 Analysis
Defines what this verification method means (See 
Appendix B  of this handbook) and how it will be 
applied to this system.
4.2.2 Inspection
4.2.3 Demonstration
Appendix B  of this handbook) and how it will be applied 
to this system.
4.2.4 Test
to this system. This category may need to be broken down 
into further categories.218
4.2.4.1 Qualification T esting
This section describes the test philosophy for the envi -
ronmental and other testing that is performed at higher 
than normal levels to ascertain margins and perfor -
mance in worst-case scenarios. Includes descriptions 
of how the minimum and maximum extremes will be 
determined for various types of tests (thermal, vibra -
tion, etc.), whether it will be performed at a component, 
subsystem, or system level, and the pedigree (flight unit, 
qualification unit, engineering unit, etc.) of the units 
these tests will be performed on.
4.2.4.2 Other T esting
This section describes any other testing that will be used 
as part of the verification activities that are not part 
of the qualification testing. It includes any testing of 
requirements within the normal operating range of the 
end item. It may include some engineering tests that will 
form the foundation or provide dry runs for the official 
verification testing.
4.3 Validation Methods
This section defines and describes the methods to be used 
during the validation activities.
Defines what this validation method means (See 
to this system.4.2.4 Test
to this system. This category may need to be broken down

into further categories such as end-to-end testing, testing 
with humans, etc.)
4.4 Certification Process
Describes the overall process by which the results of these 
verification and validation activities will be used to cer -
tify that the system meets its requirements and expec -
tations and is ready to be put into the field or fly. In 
addition to the verification and validation results, the 
certification package may also include special forms, 
reports, safety documentation, drawings, waivers, or 
other supporting documentation.
4.5 Acceptance Testing
Describes the philosophy of how/which of the verification/
validation activities will be performed on each of the 
operational units as they are manufactured/coded and 
are readied for flight/use. Includes how/if data packages 
will be developed and provided as part of the delivery.
5.0 Verification and Validation 
5.1  System Design and Verification 
and Validation Flow
This section describes how the system units/modules will 
flow from manufacturing/coding through verification 
and validation. Includes whether each unit will be veri -
fied/validated separately, or assembled to some level and 
then evaluated or other statement of flow.
5.2 Test Articles
This section describes the pedigree of test articles that will 
be involved in the verification/validation activities. This 219
may include descriptions of breadboards, prototypes, 
engineering units, qualification units, protoflight units, 
flight units, or other specially named units. A definition 
of what is meant by these terms needs to be included to 
ensure clear understanding of the expected pedigree of 
each type of test article. Descriptions of what kind of test/
analysis activities will be performed on each type of test 
article is included.
5.3 Support Equipment
This section describes any special support equipment that 
will be needed to perform the verification/validation 
activities. This will be a more detailed description than 
is stated in Section 3.4 of this outline.
5.4 Facilities
This section identifies and describes major facilities that 
will be needed in order to accomplish the verification 
and validation activities. These may include environ -
mental test facilities, computational facilities, simula -
tion facilities, training facilities, test stands, and other 
facilities as needed.
6.0 End Item Verification and 
Validation
This section describes in detail the V&V activities that 
will be applied to the lower-level subsystems/elements/
end items. It can point to other stand-alone descrip -
tions of these tests if they will be generated as part of 
organizational responsibilities for the products at each 
product  layer.
6.1 End Item A
This section focuses in on one of the lower-level end items 
and describes in detail what type of verification activi -
ties it will undergo.6.1.1 Developmental/Engineering Unit Evaluations
This section describes what kind of testing, analysis, 
demonstrations, or inspections the prototype/engineering 
or other types of units/modules will undergo prior to per -
forming official verification and validation.
6.1.2 Verification Activities
This section describes in detail the verification activities 
that will be performed on this end item.
6.1.2.1 Verification by T esting
This section describes all verification testing that will be 
performed on this end item.
6.1.2.1.1  Qualification Testing
This section describes the test environmental and other 
testing that is performed at higher than normal levels 
to ascertain margins and performance in worst-case 
scenarios. It includes what minimum and maximum 
extremes will be used on qualification tests (thermal, 
vibration, etc.) of this unit, whether it will be performed 
at a component, subsystem, or system level, and the ped -
igree (flight unit, qualification unit, engineering unit, 
etc.) of the units these tests will be performed on.
6.1.2.1.2  Other Testing
This section describes all other verification tests that are 
not performed as part of the qualification testing. These 
will include verification of requirements in the normal 
operating ranges.
6.1.2.2 Verification by Analysis
This section describes the verifications that will be per -
formed by analysis (including verification by similarity). 
This may include thermal analysis, stress analysis, anal -
ysis of fracture control, materials analysis, Electrical, 
Electronic, and Electromechnical (EEE) parts analysis, 
and other analyses as needed for the verification of this 
end item.220
6.1.2.3 Verification by Inspection
formed for this end item by inspection.
6.1.2.4 Verification Demonstration
formed for this end item by demonstration.
6.1.3 Validation Activities
6.1.3.1 Validation by T esting
This section describes what validation tests will be per -
formed on this end item.
6.1.3.2 Validation by Analysis
This section describes the validation that will be per -
formed for this end item through analysis.
6.1.3.3 Validation by Inspection
formed for this end item through inspection.
6.1.3.4 Validation by Demonstration
This section describes the validations that will be per -
6.1.4 Acceptance Testing
This section describes the set of tests, analysis, demonstra -
tions, or inspections that will be performed on the flight/
final version of the end item to show it has the same 
design as the one that is being verified, that the work -
manship on this end item is good, and that it performs 
the identified functions properly.
6.n End Item n
In a similar manner as above, a description of how each 
end item that makes up the system will be verified and 
validated is made.7.0 System Verification and 
7.1 End-Item Integration
This section describes how the various end items will be 
assembled/integrated together, verified and validated. 
For example, the avionics and power systems may be 
integrated and tested together to ensure their interfaces 
and performance is as required and expected prior to 
integration with a larger element. This section describes 
the verification and validation that will be performed 
on these major assemblies. Complete system integration 
will be described in later sections.
7.1.1 Developmental/Engineering Unit Evaluations
This section describes the unofficial (not the formal ver -
ification/validation) testing/analysis that will be per -
formed on the various assemblies that will be tested 
together and the pedigree of the units that will be used. 
This may include system-level testing of configurations 
using engineering units, breadboard, simulators, or 
other forms or combination of forms.
7.1.2 Verification Activities
This section describes the verification activities that will 
be performed on the various assemblies.
7.1.2.1 Verification by T esting
performed on the various assemblies. The section may be 
broken up to describe qualification testing performed on 
the various assemblies and other types of testing.
7.1.2.2 Verification by Analysis
This section describes all verification analysis that will be 
performed on the various assemblies.
7.1.2.3 Verification by Inspection
This section describes all verification inspections that 
will be performed on the various assemblies.221
7.1.2.4 Verification by Demonstration
This section describes all verification demonstrations 
that will be performed on the various assemblies.
7.1.3 Validation Activities
7.1.3.1 Validation by T esting
This section describes all validation testing that will be 
7.1.3.2 Validation by Analysis
This section describes all validation analysis that will be 
7.1.3.3 Validation by Inspection
This section describes all validation inspections that will 
7.1.3.4 Validation by Demonstration
This section describes all validation demonstrations that 
will be performed on the various assemblies.
7.2 Complete System Integration
This section describes the verification and validation 
activities that will be performed on the systems after all 
its assemblies are integrated together to form the complete 
integrated system. In some cases this will not be practical. 
Rationale for what cannot be done should be captured.
7.2.1 Developmental/Engineering Unit Evaluations
This section describes the unofficial (not the formal 
verification/validation) testing/analysis that will be 
performed on the complete integrated system and the

performed on the complete integrated system and the 
pedigree of the units that will be used. This may include 
system-level testing of configurations using engineering 
units, breadboard, simulators, or other forms or combi -
nation of forms.
7.2.2 Verification Activities
be performed on the completely integrated system7.2.2.1 Verification T esting
performed on the integrated system. The section may be 
broken up to describe qualification testing performed at 
the integrated system level and other types of testing.
7.2.2.2 Verification Analysis
performed on the integrated system.
7.2.2.3 Verification Inspection
will be performed on the integrated system.
7.2.2.4 Verification Demonstration
that will be performed on the integrated system.
7.2.3 Validation Activities
This section describes the validation activities that will 
be performed on the completely integrated system.
7.2.3.1 Validation by T esting
7.2.3.2 Validation by Analysis
7.2.3.3 Validation by Inspection
This section describes the validation inspections that will 
be performed on the integrated system.
7.2.3.4 Validation by Demonstration
This section describes the validation demonstrations that 
will be performed on the integrated system.222
8.0 Program Verification and 
This section describes any further testing that the system 
will be subjected to. For example, if the system is an 
instrument, the section may include any verification/vali -
dation that the system will undergo when integrated into 
its spacecraft/platform. If the system is a spacecraft, the 
section may include any verification/validation the system 
will undergo when integrated with its launch vehicle.
8.1 Vehicle Integration
This section describes any further verification or valida -
tion activities that will occur when the system is inte -
grated with its external interfaces.
8.2 End-to-End Integration
This section describes any end-to-end testing that the 
system may undergo. For example, this configuration 
would include data being sent from a ground control 
center through one or more relay satellites to the system 
and back.
8.3 On-Orbit V&V Activities
This section describes any remaining verification/valida -
tion activities that will be performed on a system after it 
reaches orbit or is placed in the field.
9.0 System Certification 
Products
This section describes the type of products that will 
be generated and provided as part of the certification 
process. This package may include the verification and 
validation matrix and results, pressure vessel certifica -
tions, special forms, materials certifications, test reports 
or other products as is appropriate for the system being 
verified and validated.Appendix A:  Acronyms and Abbreviations
This is a list of all the acronyms and abbreviations used 
in the V&V Plan and their spelled-out meaning.
Appendix B: Definition of Terms
This section is a definition of the key terms that are used 
in the V&V Plan.
Appendix C:  Requirement Verification 
Matrix
The V&V Plan needs to be baselined after the comments 
from PDR are incorporated. The information in this 
section may take various forms. It could be a pointer to 
another document or model where the matrix and its 
results may be found. This works well for large projects 
using a requirements-tracking application. The infor -
mation in this section could also be the requirements 
matrix filled out with all but the results information and 
a pointer to where the results can be found. This allows 
the key information to be available at the time of base -
lining. For a smaller project, this may be the completed 
verification matrix. In this case, the V&V Plan would 
be filled out as much as possible before. See Appendix D  
for an example of a verification matrix.
Appendix D:  Validation Matrix
As with the verification matrix, this product may take 
various forms from a completed matrix to just a pointer 
for where the information can be found. Appendix E  
provides an example of a validation matrix.223
Appendix J: SEMP Content Outline
J.1 SEMP Content
The Systems Engineering Management Plan (SEMP) 
is the foundation document for the technical and engineering activities conducted during the project. The SEMP conveys information to all of the person -
nel on the technical integration methodologies and activities for the project within the scope of the proj -
ect plan. SEMP content can exist as a stand-alone document or, for smaller projects, in higher-level project documentation.
The SEMP provides the specifics of the technical 
effort and describes what technical processes will be used, how the processes will be applied using appro -
priate activities, how the project will be organized to accomplish the activities, and the resources required for accomplishing the activities. The SEMP provides the framework for realizing the appropriate work products that meet the entry and success criteria of the applicable project life cycle phases to provide management with necessary information for assess -
ing technical progress.
Because the SEMP provides the specific technical 
and management information to understand the technical integration and interfaces, its documenta -
tion and approval serve as an agreement within the project of how the technical work will be conducted. The SEMP communicates to the team itself, manag -
ers, customers, and other stakeholders the technical effort that will be performed by the assigned techni -
cal team.The technical team, working under the overall pro -
gram/project plan, develops and updates the SEMP as necessary. The technical team works with the proj -
ect manager to review the content and obtain con -
currence. The SEMP includes the following three general sections:
1. Technical program planning and control, which describe the processes for planning and control of the engineering efforts for the design, develop -
ment, test, and evaluation of the system.
2. Systems engineering processes, which include spe -
cific tailoring of the systems engineering process as described in the NPR, implementation pro -
cedures, trade study methodologies, tools, and models to be used.
3. Engineering specialty integration describes the integration of the technical disciplines’ efforts into the systems engineering process and sum -
marizes each technical discipline effort and cross references each of the specific and relevant plans.
The SEMP outline in this appendix is guidance to be used in preparing a stand-alone project SEMP. The level of detail in the project SEMP should be adapted based on the size of the project. For a small project, the material in the SEMP can be placed in the project plan’s technical summary, and this annotated outline should be used as a topic guide.
Some additional important points on the SEMP:224
NASA SYSTEMS ENGINEERING HANDBOOKAppendix J: SEMP Content Outline
• The SEMP is a living document. The initial SEMP 
is used to establish the technical content of the 
engineering work early in the Formulation Phase 
for each project and updated as needed through -
out the project life cycle. Table J-1 provides some 
high level guidance on the scope of SEMP con -
tent based on the life cycle phase.
• Project requirements that have been tailored or 
significant customization of SE processes should 
be described in the SEMP.
• For multi-level projects, the SEMP should be consis -
tent with higher-level SEMPs and the project plan.• For a technical effort that is contracted, the SEMP 
should include details on developing requirements 
for source selection, monitoring performance, and 
transferring and integrating externally produced 
products to NASA.
J.2 Terms Used
Terms used in the SEMP should have the same mean -
ing as the terms used in the NPR 7123.1, Systems 
Engineering Processes and Requirements.225
J.3 Annotated Outline
Title Page
(Provide a title for the candidate program/project and designate  
a short title or proposed acronym in parenthesis, if appropriate.)
.
.
.
Designated Governing Authority/Technical Authority Date
Program/Project Manager Date
Chief Engineer Date
Date
Date
By signing this document, signatories are certifying that the content herein is acceptable as direction 
for engineering and technical management of this program/project and that they will ensure its

Title Page
.
.
.
Date
Date
for engineering and technical management of this program/project and that they will ensure its 
implementation by those over whom they have authority.226
1.0 Purpose and Scope
This section provides a brief description of the purpose, 
scope, and content of the SEMP.
• Purpose: This section should highlight the intent of 
the SEMP to provide the basis for implementing and 
communicating the technical effort.
• Scope: The scope describes the work that encompasses 
the SE technical effort required to generate the work 
products. The plan is used by the technical team to 
provide personnel the information necessary to suc -
cessfully accomplish the required task.
• Content:  This section should briefly describe the orga -
nization of the document.
2.0 Applicable Documents
This section of the SEMP lists the documents applicable 
to this specific project and its SEMP implementation. 
This section should list major standards and procedures 
that this technical effort for this specific project needs 
to follow. Examples of specific procedures to list could 
include procedures for hazardous material handling, 
crew training plans for control room operations, special 
instrumentation techniques, special interface documen -
tation for vehicles, and maintenance procedures specific 
to the project.
3.0 Technical Summary
This section contains an executive summary describing 
the problem to be solved by this technical effort and the 
purpose, context, and products to be developed and inte -
grated with other interfacing systems identified.
Key Questions
1. What is the problem we’re trying to solve?
2. What are the influencing factors?
3. What are the critical questions?4. What are the overall project constraints 
in terms of cost, schedule, and technical 
performance
5. How will we know when we have adequately 
defined the problem?
6. Who are the customers?
7. Who are the users?
8. What are the customer and user priorities?
9. What is the relationship to other projects?
3.1 System Description
This section contains a definition of the purpose of the 
system being developed and a brief description of the 
purpose of the products of the product layer of the system 
structure to which this SEMP applies. Each product layer 
includes the system end products and their subsystems 
and the supporting or enabling products and any other 
work products (plans, baselines) required for the devel -
opment of the system. The description should include 
any interfacing systems and system products, including 
humans with which the system products will interact 
physically, cognitively, functionally, or electronically.
3.2 System Structure
This section contains an explanation of how the tech -
nical portion of the product layer (including enabling 
products, technical cost, and technical schedule) will be 
developed, how the resulting product layers will be inte -
grated into the project portion of the WBS, and how the 
overall system structure will be developed. This section 
contains a description of the relationship of the specifica -
tion tree and the drawing tree with the products of the 
system structure and how the relationship and interfaces 
of the system end products and their life cycle-enabling 
products will be managed throughout the planned tech -
nical effort.
3.3 Product Integration
This section contains an explanation of how the products 
will be integrated and describes clear organizational 227
responsibilities and interdependencies and whether the 
organizations are geographically dispersed or managed 
across Centers. This section should also address how 
products created under a diverse set of contracts are to 
be integrated, including roles and responsibilities. This 
includes identifying organizations—intra-and inter-
NASA, other Government agencies, contractors, or 
other partners—and delineating their roles and respon -
sibilities. Product integration includes the integration of 
analytical products.
When components or elements will be available for inte -
gration needs to be clearly understood and identified on 
the schedule to establish critical schedule issues.
3.4 Planning Context
This section contains the programmatic constraints (e.g., 
NPR 7120.5) that affect the planning and implemen -
tation of the common technical processes to be applied 
in performing the technical effort. The constraints pro -
vide a linkage of the technical effort with the applicable 
product life cycle phases covered by the SEMP including, 
as applicable, milestone decision gates, major technical 
reviews, key intermediate events leading to project com -
pletion, life cycle phase, event entry and success criteria, 
and major baseline and other work products to be deliv -
ered to the sponsor or customer of the technical effort.
3.5 Boundary of Technical Effort
This section contains a description of the boundary of 
the general problem to be solved by the technical effort, 
including technical and project constraints that affect 
the planning. Specifically, it identifies what can be con -
trolled by the technical team (inside the boundary) and 
what influences the technical effort and is influenced by 
the technical effort but not controlled by the technical 
team (outside the boundary). Specific attention should 
be given to physical, cognitive, functional, and elec -
tronic interfaces across the boundary.A description of the boundary of the system can include 
• Definition of internal and external elements/items 
involved in realizing the system purpose as well as 
the system boundaries in terms of space, time, physi -
cal, and operational.
• Identification of what initiates the transitions of 
the system to operational status and what initiates 
its disposal is important. General and functional 
descriptions of the subsystems inside the boundary.
• Current and established subsystem performance 
• Interfaces and interface characteristics.
• Functional interface descriptions and functional 
flow diagrams.
• Key performance interface characteristics.
• Current integration strategies and architecture.
• Documented Human System Integration Plan (HSIP)
3.6 Cross References
This section contains cross references to appropriate 
nontechnical plans and critical reference material that 
interface with the technical effort. It contains a sum -
mary description of how the technical activities covered 
in other plans are accomplished as fully integrated parts 
of the technical effort.
4.0 Technical Effort Integration
This section describes how the various inputs to the tech -
nical effort will be integrated into a coordinated effort 
that meets cost, schedule, and performance objectives.228
The section should describe the integration and coordina -
tion of the specialty engineering disciplines into the systems 
engineering process during each iteration of the processes. 
Where there is potential for overlap of specialty efforts, 
the SEMP should define the relative responsibilities and 
authorities of each specialty. This section should contain, 
as needed, the project’s approach to the following:
• Concurrent engineering
• The activity phasing of specialty engineering
• The participation of specialty disciplines
• The involvement of specialty disciplines,
• The role and responsibility of specialty disciplines,
• The participation of specialty disciplines in system 
decomposition and definition
• The role of specialty disciplines in verification and 
• Reliability
• Maintainability
• Quality assurance
• Integrated logistics
• Human engineering
• Safety
• Producibility
• Survivability/vulnerability
• National Environmental Policy Act (NEPA) 
compliance
• Launch approval/flight readiness
The approach for coordination of diverse technical dis -
ciplines and integration of the development tasks should 
be described. For example, this can include the use of 
multidiscipline integrated teaming approaches—e.g., 
an HSI team—or specialized control boards. The scope 
and timing of the specialty engineering tasks should be 
described along with how specialty engineering disci -
plines are represented on all technical teams and during 
all life cycle phases of the project.4.1 Responsibility and Authority
This section describes the organizing structure for the 
technical teams assigned to this technical effort and 
includes how the teams will be staffed and managed.
1. What organization/panel will serve as the des -
ignated governing authority for this project?
2. How will multidisciplinary teamwork be achieved?
3. What are the roles, responsibilities, and 
authorities required to perform the activities 
of each planned common technical process?
4. What should be the planned technical staff -
ing by discipline and expertise level?
5. What is required for technical staff training?
6. How will the assignment of roles, respon -
sibilities, and authorities to appropriate

sibilities, and authorities to appropriate 
project stakeholders or technical teams 
be accomplished?
7. How are we going to structure the project to 
enable this problem to be solved on sched -
ule and within cost?
8. What does systems engineering manage -
ment bring to the table?
The section should provide an organization chart and 
denote who on the team is responsible for each activity. It 
should indicate the lines of authority and responsibility. 
It should define the resolution authority to make deci -
sions/decision process. It should show how the engineers/
engineering disciplines relate.
The systems engineering roles and responsibilities need 
to be addressed for the following: project office, user, 
Contracting Officer’s Representative (COR), systems 
engineering, design engineering, specialty engineering, 
and contractor.229
4.2 Contractor Integration
This section describes how the technical effort of in-house 
and external contractors is to be integrated with the 
NASA technical team efforts. The established technical 
agreements should be described along with how contrac -
tor progress will be monitored against the agreement, 
how technical work or product requirement change 
requests will be handled, and how deliverables will be 
accepted. The section specifically addresses how inter -
faces between the NASA technical team and the con -
tractor will be implemented for each of the 17 common 
technical processes. For example, it addresses how the 
NASA technical team will be involved with reviewing 
or controlling contractor-generated design solution defi -
nition documentation or how the technical team will be 
involved with product verification and product valida -
tion activities.
Key deliverables for the contractor to complete their sys -
tems and those required of the contractor for other proj -
ect participants need to be identified and established on 
the schedule.
4.3 Analytical Tools that Support Integration
This section describes the methods (such as integrated 
computer-aided tool sets, integrated work product data -
bases, and technical management information systems) 
that will be used to support technical effort integration.
5.0  Common Technical Processes 
Each of the 17 common technical processes will have a 
separate subsection that contains a plan for performing 
the required process activities as appropriately tailored. 
(See NPR 7123.1 for the process activities required and 
tailoring.) Implementation of the 17 common techni -
cal processes includes (1) the generation of the outcomes 
needed to satisfy the entry and success criteria of the 
applicable product life cycle phase or phases identified in 
D.4.4.4, and (2) the necessary inputs for other technical processes. These sections contain a description of the 
approach, methods, and tools for:
• Identifying and obtaining adequate human and 
nonhuman resources for performing the planned 
process, developing the work products, and providing 
the services of the process.
• Assigning responsibility and authority for perform -
ing the planned process (e.g., RACI matrix, [ http://
en.wikipedia.org/wiki/Responsibility_assignment_
matrix ]), developing the work products, and provid -
ing the services of the process.
• Training the technical staff performing or supporting 
the process, where training is identified as needed.
• Designating and placing designated work products 
of the process under appropriate levels of configura -
tion management.
• Identifying and involving stakeholders of the process.
• Monitoring and controlling the systems engineering 
• Identifying, defining, and tracking metrics and 
success.
• Objectively evaluating adherence of the process and 
the work products and services of the process to the 
applicable requirements, objectives, and standards 
and addressing noncompliance.
• Reviewing activities, status, and results of the process 
with appropriate levels of management and resolving 
issues.
This section should also include the project-specific 
description of each of the 17 processes to be used, including 230
the specific tailoring of the requirements to the system 
and the project; the procedures to be used in implement -
ing the processes; in-house documentation; trade study 
methodology; types of mathematical and/or simulation 
models to be used; and generation of specifications.
1. What are the systems engineering processes 
for this project?
2. What are the methods that we will apply for 
each systems engineering task?
3. What are the tools we will use to support these 
methods? How will the tools be integrated?
4. How will we control configuration development?
5. How and when will we conduct technical 
reviews?
6. How will we establish the need for and man -
age trade-off studies?
7. Who has authorization for technical change 
control?
8. How will we manage requirements? inter -
faces? documentation?
6.0 Technology Insertion
This section describes the approach and methods for 
identifying key technologies and their associated risks 
and criteria for assessing and inserting technologies, 
including those for inserting critical technologies from 
technology development projects. An approach should be 
developed for appropriate level and timing of technology 
insertion. This could include alternative approaches to 
take advantage of new technologies to meet systems needs 
as well as alternative options if the technologies do not 
prove appropriate in result or timing. The strategy for 
an initial technology assessment within the scope of the 
project requirements should be provided to identify tech -
nology constraints for the system.Key Questions
1. How and when will we insert new of special 
technology into the project?
2. What is the relationship to research and 
development efforts? How will they sup -
port the project? How will the results be 
incorporated?
3. How will we incorporate system elements 
provided by others? How will these items be 
certified for adequacy?
4. What facilities are required?
5. When and how will these items be transi -
tioned to be part of the configuration?
7.0  Additional SE Functions and 
Activities
This section describes other areas not specifically included 
in previous sections but that are essential for proper plan -
ning and conduct of the overall technical effort.
7.1 System Safety
This section describes the approach and methods for con -
ducting safety analysis and assessing the risk to operators, 
the system, the environment, or the public.
7.2 Engineering Methods and Tools
This section describes the methods and tools that are 
not included in the technology insertion sections but 
are needed to support the overall technical effort. It 
identifies those tools to be acquired and tool training 
This section defines the development environment for 
the project, including automation, simulation, and soft -
ware tools. If required, it describes the tools and facilities 
that need to be developed or acquired for all disciplines 
on the project. It describes important enabling strategies 
such as standardizing tools across the project, or utiliz -
ing a common input and output format to support a 231
broad range of tools used on the project. It defines the 
requirements for information management systems and 
for using existing elements. It defines and plans for the 
training required to use the tools and technology across 
the project.
7.3 Specialty Engineering
This section describes engineering discipline and spe -
cialty requirements that apply across projects and the 
WBS models of the system structure. Examples of these 
requirement areas would include planning for safety, 
reliability, human factors, logistics, maintainability, 
quality, operability, and supportability. It includes esti -
mates of staffing levels for these disciplines and incorpo -
rates them with the project requirements.
7.4 Technical Performance Measures
a. This section describes the TPMs that have been 
derived from the MOEs and MOPs for the project. 
The TPMs are used to define and track the techni -
cal progress of the systems engineering effort. (The 
unique identification numbers in red reference the 
corresponding requirement in NPR 7123.1.) The 
performance metrics need to address the minimally 
required TPMs as defined in NPR 7123.1. These 
include:
1. Mass margins for projects involving hardware  
[SE-62] .
2. Power margins for projects that are powered 
[SE-63] .
3. Review Trends including closure of review action 
documentation (Request for Action, Review Item 
Discrepancies, and/or Action Items as established 
by the project) for all software and hardware 
projects [SE-64] .b. Other performance measure that should be con -
sidered by the project include:
 »Requirement trends (percent growth, TBD/TBR

include:
[SE-62] .
[SE-63] .
 »Requirement trends (percent growth, TBD/TBR 
closures, number of requirement changes);
 »Interface trends (percent ICD approval, TBD/
TBR burndown, number of interface require -
ment changes);
 »Verification trends (closure burndown, number 
of deviations/waivers approved/open);
 »Software-unique trends (number of require -
ments per build/release versus plan);
 »Problem report/discrepancy report trends (num -
ber open, number closed);
 »Cost trends (plan, actual, UFE, EVM, NOA);
 »Schedule trends (critical path slack/float, critical 
milestone dates); and
 »Staffing trends (FTE, WYE).
1. What metrics will be used to measure tech -
nical progress?
2. What metrics will be used to identify process 
improvement opportunities?
3. How will we measure progress against the 
plans and schedules?
4. How often will progress be reported? By 
whom? To whom?
7.5 Heritage
This section describes the heritage or legacy products that 
will be used in the project. It should include a discussion 
of which products are planned to be used, the rationale 
for their use, and the analysis or testing needed to assure 
they will perform as intended in the stated use.232
7.6 Other
This section is reserved to describe any unique SE func -
tions or activities for the project that are not covered in 
other sections.
8.0  Integration with the Project Plan 
and Technical Resource Allocation
This section describes how the technical effort will inte -
grate with project management and defines roles and 
responsibilities. It addresses how technical requirements 
will be integrated with the project plan to determine 
the allocation of resources, including cost, schedule, and 
personnel, and how changes to the allocations will be 
coordinated.
1. How will we assess risk? What thresholds 
are needed for triggering mitigation activi -
ties? How will we integrate risk management 
into the technical decision process?
2. How will we communicate across and out -
side of the project?
3. How will we record decisions?
4. How do we incorporate lessons learned from 
other projects?
This section describes the interface between all of the tech -
nical aspects of the project and the overall project man -
agement process during the systems engineering planning 
activities and updates. All activities to coordinate tech -
nical efforts with the overall project are included, such 
as technical interactions with the external stakeholders, 
users, and contractors.9.0 Compliance Matrices
Appendix H.2 in NPR 7123.1A is the basis for the com -
pliance matrix for this section of the SEMP. The proj -
ect will complete this matrix from the point of view of 
the project and the technical scope. Each requirement 
will be addressed as compliant, partially compliant, or 
noncompliant. Compliant requirements should indicate 
which process or activity addresses the compliance. For 
example, compliance can be accomplished by using a 
Center process or by using a project process as described 
in another section of the SEMP or by reference to another 
documented process. Noncompliant areas should state 
the rationale for noncompliance.
Appendices
Appendices are included, as necessary, to provide a 
glossary, acronyms and abbreviations, and informa -
tion published separately for convenience in document 
maintenance. Included are: (1) information that may 
be pertinent to multiple topic areas (e.g., description of 
methods or procedures); (2) charts and proprietary data 
applicable to the technical efforts required in the SEMP; 
and (3) a summary of technical plans associated with 
the project. Each appendix should be referenced in one 
of the sections of the engineering plan where data would 
normally have been provided.
Templates
Any templates for forms, plans, or reports the technical 
team will need to fill out, like the format for the veri -
fication and validation plan, should be included in the 
appendices.
References
This section contains all documents referenced in the text 
of the SEMP.233
NASA SYSTEMS ENGINEERING HANDBOOKAppendix J: SEMP Content OutlineTABLE J-1  Guidance on SEMP Content per Life-Cycle Phase
SEMP 
SectionSEMP 
Subsec -
tionPre-Phase A
KDP APhase A
KDP BPhase B
KDP CPhase C
KDP DPhase D
KDP EPhase E
KDP FPhase F
MCR SRR SDR/MDR PDR CDR SIR ORR MRR/FRR DR DRR
Purpose and 
ScopeFinal Final Final Final Final Final Final Final Final Final
Applicable DocumentsInitial Initial Initial Final Final Final Final Final Final Final
Technical SummaryFinal Final Final Final Final Final Final Final Final Final
System DescriptionInitial Initial Initial Final Final Final Final Final Final Final
System StructureProduct IntegrationDefine thru SDR 
timeframeDefine 
thru SDR 
thru SDR 
timeframeDefine thru 
SIRDefine thru SIRDefine thru SIRDefine sustaining thru 
end of programDefine 
sustaining 
thru end of 
programDefine sustaining 
thru end of 
thru end of 
program
Planning 
ContextDefine thru SDR 
thru SDR 
thru SDR 
thru end of 
thru end of 
thru end of 
program
Boundary 
of Technical 
EffortInitial Initial Initial Final Final Final Final Final Final Final
Cross ReferencesInitial Initial Initial Final Final Final Final Final Final Final
Technical Effort IntegrationResponsi -
bility and AuthorityDefine thru SDR timeframeDefine thru SDR timeframeDefine thru SDR timeframeDefine thru SIR timeframeDefine thru SIR timeframeDefine thru SIR timeframeDefine sustain -
ing Roles and Responsibilities 
through end of 
programDefine sus -
taining Roles and Respon -
sibilities through end 
of programDefine sus -
taining Roles 
and Respon -
of program
Contractor 
IntegrationDefine acquisitions neededDefine insight/oversight 
through SIR 
timeframeDefine sustaining insight/
oversight 
through end of program
Support IntegrationDefine acquisitions neededDefine insight/oversight 
timeframeDefine sus -
taining insight/oversight 
program
(continued)234
NASA SYSTEMS ENGINEERING HANDBOOKAppendix J: SEMP Content OutlineSEMP 
Subsec -
Common 
Technical Pro -
cesses Imple -
mentationProcesses 
defined for 
Concept 
Develop -
ment and 
FormulationProcesses 
the Design 
PhaseProcesses 
added for the 
integration 
and 
PhaseUpdate 
processes. 
Define close 
out processes 
and sustaining 
engineering 
processes
InsertionDefine 
technologies 
to be 
developedDefine deci -
sion process 
for on ramps 
and off 
ramps of 
technology 
effortsDefine technol -
ogy sustaining 
effort through 
end of program.
Additional SE 
Functions and 
ActivitiesSystem 
SafetyDefine process 
through CDRDefine sustain -
ing Roles and 
Responsibilities 
program
Engineering 
Methods 
and toolsDefine process 
program
Specialty 
EngineeringDefine process 
program
Integration 
with the 
Project Plan 
and Technical 
Resource 
AllocationDefine 
through SDR 
through SIRDefine 
programDefine 
through end 
of programDefine 
of program
Compliance 
Matrix 
(Appendix H.2 
of SE NPR)Initial Initial Initial Final Final Final Final Final Final Final
Appendices As required As required As required As required As required As required As required As required As required As required
Templates As required As required As required As required As required As required As required As required As required As required
References As required As required As required As required As required As required As required As required As required As required235
Appendix K: Technical Plans
The following table represents a typical expectation of maturity of some of the key technical plans developed 
during the SE processes. This example is for a space flight project. Requirements for work product maturity can be found in the governing PM document (i.e., NPR 7120.5) for the associated type of project.
TABLE K-1  Example of Expected Maturity of Key Technical Plans
Plan Pre-
Phase APhase A Phase BPhase C Phase D Phase EPhase FRef. Page
MCR SRR SDR/MDRPDR CDR SIR ORR MRR/ FRRDR DRR
Systems Engineering 
Management PlanP B U U U U U U U U
Risk Management Plan A B U U U
Integrated Logistics Support PlanA P P B U
Technology Development PlanB U U U
Review Plan P B U U U U U U U U
Verification and Validation PlanA A P B U
Integration Plan P B U

Plan Pre-
Configuration Management PlanB U U
Data Management Plan B U U
Human Systems Integration PlanB U U U
Software Management PlanP B U
Reliability and Maintainability PlanP B U
Mission Operations Plan P B U
Project Protection Plan P B U U U U U U
Decommissioning Plan A B U
Disposal Plan A B U U
A = Approach  B = B aseline  P = P reliminary  U = U pdate236
Appendix L:  I nterface Requirements  
Document Outline
State the purpose of this document and briefly iden -
tify the interface to be defined. (For example, “This 
IRD defines and controls the interface(s) requirements 
between ______ and ______.”)
1.2 Precedence
Define the relationship of this document to other pro -
gram documents and specify which is controlling in the 
event of a conflict.
1.3  Responsibility and Change 
Authority
State the responsibilities of the interfacing organiza -
tions for development of this document and its contents. 
Define document approval authority (including change 
approval authority).
2.0 Documents
List binding documents that are invoked to the extent 
specified in this IRD. The latest revision or most recent version should be listed. Documents and requirements 
imposed by higher-level documents (higher order of pre -
cedence) should not be repeated.
List any document that is referenced in the text in this 
subsection.3.0 Interfaces
3.1 General
In the subsections that follow, provide the detailed descrip -
tion, responsibilities, coordinate systems, and numerical requirements as they relate to the interface plane.
3.1.1  Interface Description
Describe the interface as defined in the system specifi -
cation. Use tables, figures, or drawings as appropriate.
3.1.2  Interface Responsibilities
Define interface hardware and interface boundary responsibilities to depict the interface plane. Use tables, figures, or drawings as appropriate.
3.1.3  Coordinate Systems
Define the coordinate system used for interface require -
ments on each side of the interface. Use tables, figures, or drawings as appropriate.
3.1.4   Engineering Units, Tolerances, and  
Conversion
Define the measurement units along with tolerances. If required, define the conversion between measure -
ment systems.
3.2 Interface Requirements
In the subsections that follow, define structural limiting values at the interface, such as interface loads, forcing functions, and dynamic conditions. Define the interface 
requirements on each side of the interface plane.237
NASA SYSTEMS ENGINEERING HANDBOOKAppendix L: Interface RequirementsDocument Outline 
3.2.1 Mass Properties
Define the derived interface requirements based on the 
allocated requirements contained in the applicable speci -
fication pertaining to that side of the interface. For exam -
ple, this subsection should cover the mass of the element.
3.2.2 Structural/Mechanical
Define the derived interface requirements based on 
the allocated requirements contained in the applicable 
specification pertaining to that side of the interface. For 
example, this subsection should cover attachment, stiff -
ness, latching, and mechanisms.
3.2.3 Fluid
example, this subsection should cover fluid areas such as 
thermal control, O2 and N2, potable and waste water, 
fuel cell water, and atmospheric sampling.
3.2.4 Electrical (Power)
example, this subsection should cover various electric 
current, voltage, wattage, and resistance levels.
3.2.5 Electronic (Signal)
example, this subsection should cover various signal types 
such as audio, video, command data handling, and 
navigation.
3.2.6 Software and Data
specification pertaining to that side of the interface. For example, this subsection should cover various data stan -
dards, message timing, protocols, error detection/correc -
tion, functions, initialization, and status.
3.2.7 Environments
example, cover the dynamic envelope measures of the ele -
ment in English units or the metric equivalent on this 
side of the interface.
3.2.7.1 Electromagnetic Effects
3.2.7.1.a  Electromagnetic Compatibility
Define the appropriate electromagnetic compatibility 
requirements. For example, the end-item-1-to-end-item-2 
interface shall meet the requirements [to be determined] 
of systems requirements for electromagnetic compatibility.
3.2.7.1.b  Electromagnetic Interference
Define the appropriate electromagnetic interference 
requirements. For example, the end-item-1-to-end-
item-2 interface shall meet the requirements [to be 
determined] of electromagnetic emission and susceptibil -
ity requirements for electromagnetic compatibility.
3.2.7.1.c  Grounding
Define the appropriate grounding requirements. For exam -
ple, the end-item-1-to-end-item-2 interface shall meet the 
requirements [to be determined] of grounding requirements.
3.2.7.1.d  Bonding
Define the appropriate bonding requirements. For 
example, the end-item-1-to-end-item-2 structural/
mechanical interface shall meet the requirements [to be 
determined] of electrical bonding requirements.
3.2.7.1.e Cable and Wire Design
Define the appropriate cable and wire design require -
ments. For example, the end-item-1-to-end-item-2 238
cable and wire interface shall meet the requirements [to 
be determined] of cable/wire design and control require -
ments for electromagnetic compatibility.
3.2.7.2 Acoustic
Define the appropriate acoustics requirements. Define 
the acoustic noise levels on each side of the interface in 
accordance with program or project requirements.
3.2.7.3 Structural Loads
Define the appropriate structural loads requirements. Define 
the mated loads that each end item should accommodate.3.2.7.4 Vibroacoustics
Define the appropriate vibroacoustics requirements. 
Define the vibroacoustic loads that each end item should 
accommodate.
3.2.7.5 Human Operability
Define the appropriate human interface requirements. 
Define the human-centered design considerations, con -
straints, and capabilities that each end item should 
3.2.8 Other Types of Interface Requirements
Define other types of unique interface requirements that 
may be applicable.239
Appendix M: CM Plan Outline
A comprehensive Configuration Management (CM) 
Plan that reflects efficient application of configura -
tion management principles and practices would nor -
mally include the following topics:
• General product definition and scope
• Description of CM activities and procedures for each major CM function
• Organization, roles, responsibilities, and resources
• Definitions of terms
• Programmatic and organizational interfaces
• Deliverables, milestones, and schedules
• Subcontract flow down requirementsThe documented CM planning should be reevalu -
ated following any significant change affecting the context and environment, e.g., changes in suppliers or supplier responsibilities, changes in diminishing 
manufacturing sources/part obsolescence, changes in 
resource availabilities, changes in customer contract, and changes in the product. CM planning should also be reviewed on a periodic basis to make sure that an organization’s application of CM functions is current.
For additional information regarding a CM Plan, 
refer to SAE EIA-649, Rev. B.240
Appendix N:  Guidance on Technical Peer Reviews/
Inspections
This appendix has been removed. For additional guid -
ance on how to perform technical peer reviews refer 
to Appendix N in the NASA Expanded Guidance for 
Systems Engineering at https://nen.nasa.gov/web/se/
doc-repository .241
Appendix O: Reserved242
Appendix P: SOW Review Checklist
This appendix has been removed. For additional 
guidance on checklists for editorial and content review questions refer to Appendix P in the NASA 
https://nen.nasa.gov/web/se/doc-repository .243
Appendix Q: Reserved244
Appendix R: HSI Plan Content Outline
R.1 HSI Plan Overview

The Human Systems Integration (HSI) Plan docu -
ments the strategy for and planned implementation 
of HSI through a particular program’s/project’s life cycle. The intent of HSI is:
• To ensure the human elements of the total system are effectively integrated with hardware and soft -
ware elements,
• To ensure all human capital required to develop and operate the system is accounted for in life cycle costing, and
• To ensure that the system is built to accommodate the characteristics of the user population that will operate, maintain, and support the system.
The HSI Plan is specific to a program or project and applies to NASA systems engineering per NPR 7123.1, NASA Systems Engineering Processes and Requirements. The HSI Plan should address the following:
• Roles and responsibilities for integration across HSI domains;
• Roles and responsibilities for coordinating inte -
grated HSI domain inputs with the program team and stakeholders;
• HSI goals and deliverables for each phase of the life cycle;• Entry and exit criteria with defined metrics for each phase, review, and milestone;
• Planned methods, tools, requirements, processes, and standards for conducting HSI;
• Strategies for identifying and resolving HSI risks; and
• Alignment strategy with the SEMP.
The party or parties responsible for program/project HSI implementation—e.g., an HSI integrator (or team)—should be identified by the program/proj -
ect manager. The HSI integrator or team develops and maintains the HSI Plan with support from and coordination with the project manager and systems engineer.
Implementation of HSI on a program/project utilizes 
many of the tools and products already required by systems engineering; e.g., development of a ConOps, clear functional allocation across the elements of a system (hardware, software, and human), and the use of key performance measurements through the life cycle to validate and verify HSI’s effectiveness. It is not the intent of the HSI Plan or its implementation to duplicate other systems engineering plans or pro -
cesses, but rather to define the uniquely HSI effort being made to ensure the human element is given equal consideration to hardware/software elements of a program/project.245
NASA SYSTEMS ENGINEERING HANDBOOKAppendix R: HSI Plan Content Outline
R.2 HSI Plan Content Outline
Each program/project-specific HSI Plan should be 
tailored to fit the program/project’s size, scope, and 
purpose. The following is an example outline for a 
major program; e.g., space flight or aeronautics.
This section briefly identifies the ultimate objectives for this 
program/project’s HSI Plan. This section also introduces 
the intended implementers and users of this HSI Plan.
1.2 Scope
This section describes the overall scope of the HSI Plan’s 
role in documenting the strategy for and implementa -
tion of HSI. Overall, this section describes that the HSI 
Plan:
• Is a dynamic document that will be updated at key 
life cycle milestones.
• Is a planning and management guide that describes 
how HSI will be relevant to the program/project’s 
goals.
• Describes planned HSI methodology, tools, sched -
ules, and deliverables.
• Identifies known program/project HSI issues and 
concerns and how their resolutions will be addressed.
• Defines program/project HSI organizational ele -
ments, roles, and responsibilities.
• May serve as an audit trail that documents HSI 
data sources, analyses, activities, trade studies, and 
decisions not captured in other program/project 
documentation.1.3 Definitions
This section defines key HSI terms and references rele -
vant program/project-specific terms.
This section lists all documents, references, and data 
sources that are invoked by HSI’s implementation on 
the program/project, that have a direct impact on HSI 
outcomes, and/or are impacted by the HSI effort.
3.0 HSI Objectives
This section describes the system, missions to be per -
formed, expected operational environment(s), predecessor 
and/or legacy systems (and lessons learned), capability 
gaps, stage of development, etc. Additionally, reference 
should be made to the acquisition strategy for the system; 
e.g., if it is developed in-house within NASA or if major 
systems are intended for external procurement. The over -
all strategy for program integration should be referenced.
Note that this information is likely captured in other 
program/project documentation and can be referenced 
in the HSI Plan rather than repeated.
3.2 HSI Relevance
At a high level, this section describes HSI’s relevance 
to the program/project; i.e., how the HSI strategy will 
improve the program/project’s outcome. Known HSI 
challenges should be described along with mention of 
areas where human performance in the system’s oper -
ations is predicted to directly impact the probability of 
overall system performance and mission success.
4.0 HSI Strategy
4.1 HSI Strategy Summary
This section summarizes the HSI approaches, planning, 
management, and strategies for the program/project. It 
should describe how HSI products will be integrated 
across all HSI domains and how HSI inputs to program/
project systems engineering and management processes 246
contribute to system performance and help contain life 
cycle cost. This section (or Implementation Summary, 
Section 6  of this outline) should include a top-level 
schedule showing key HSI milestones.HSI RELEVANCE
Key Points
• Describe performance characteristics of the human elements known to be key drivers to a desired total 
system performance outcome.
• Describe the total system performance goals that require HSI support.
• Identify HSI concerns with legacy systems; e.g., if operations and logistics, manpower, skill selection, required training, logistics support, operators’ time, maintenance, and/or risks to safety and success exceeded expectations.
• Identify potential cost, schedule, risk, and trade-off concerns with the integration of human elements; e.g., quantity and skills of operators, maintainers, ground controllers, etc.
HSI STRATEGY
Key Points
• Identify critical program/project-specific HSI key decision points that will be used to track HSI implementation and success.
• Identify key enabling (and particularly, emerging) technologies and methodologies that may be overlooked in hardware/software systems trade studies but that may positively contribute to HSI implementation; e.g., in the areas of human performance, workload, personnel management, training, safety, and survivability.
• Describe HSI products that will be integrated with program/project systems engineering products, analyses, risks, trade studies, and activities.
• Describe efforts to ensure HSI will contribute in critically important Phase A and Pre-Phase A cost-effective design concept studies.
• Describe the plan and schedule for updating the HSI Plan through the program/project life cycle.
4.2 HSI Domains
This section identifies the HSI domains applicable to the 
program/project including rationale for their relevance.5.0  HSI Requirements, Organization, 
and Risk Management
5.1 HSI Requirements
This section references HSI requirements and stan -
dards applicable to the program/project and identi -
fies the authority that invokes them; e.g., the NASA 
Procedural Requirements (NPR) document(s) that 
invoke applicability.247
HSI DOMAINS
Key Points
• Identify any domain(s) associated with human performance capabilities and limitations whose integration 
into the program/project is likely to directly affect the probability of successful program/project outcome.
• An overview of processes to apply, document, validate, evaluate, and mitigate HSI domain knowledge and to integrate domain knowledge into integrated HSI inputs to program/project and systems engineering processes.
HSI REQUIREMENTS
Key Points
• Describe how HSI requirements that are invoked on the program/project contribute to mission success, affordability, operational effectiveness, and safety.
• HSI should include requirements that influence the system design to moderate manpower (operators, maintainers, system administrative, and support personnel), required skill sets (occupational specialties with high aptitude or skill requirements), and training requirements.
• Define the program/project-specific HSI strategy derived from NASA-STD-3001, NASA Space Flight Human-System Standard, Volume 2: Human Factors, Habitability, and Environmental Health, Standard 3.5 [V2 3005], “Human-Centered Design Process”, if applicable.
• Capture the development process and rationale for any program/project-specific requirements not derived from existing NASA standards. In particular, manpower, skill set, and training HSI requirements/goals may be so program/project-specific as to not have NASA parent standards or requirements.

Key Points
• Identify functional connections between HSI measures of effectiveness used to verify requirements and key performance measures used throughout the life cycle as indicators of overall HSI effectiveness.
5.2 HSI Organization, Roles, and Responsibilities
In this section, roles and responsibilities for program/
project personnel assigned to facilitate and/or manage HSI tasks are defined; e.g., the HSI integrator (and/or team if required by NPR 8705.2). HSI integrator/team functional responsibilities to the program are described in addition to identification of organizational elements with HSI responsibilities. Describe the relationships between HSI integrator/team, stakeholders, engineering technical teams, and governing bodies (control boards).5.2.1  HSI Organization
• Describe the HSI management structure for the program/project and identify its leaders and membership.
• Reference the organizational structure of the pro -
gram (including industry partners) and describe the roles and responsibilities of the HSI integrator/team within that structure. Describe the HSI responsible party’s relationship to other teams, including those 248
for systems engineering, logistics, risk management, 
test and evaluation, and requirements verification.
• Provide the relationship of responsible HSI person -
nel to NASA Technical Authorities (Engineering, 
Safety, and Health/Medical).
• Identify if the program/project requires NASA- 
(Government) and/or contractor-issued HSI Plans, 
and identify the responsible author(s). Describe 
how NASA’s HSI personnel will monitor and assess 
contractor HSI activities. For contractor-issued 
HSI Plans, identify requirements and processes for 
NASA oversight and evaluation of HSI efforts by 
subcontractors.
5.2.2 HSI Roles & Responsibilities
• Describe the HSI responsible personnel’s functional 
responsibilities to the program/project, addressing (as 
examples) the following:
 »developing HSI program documentation;
 »validating human performance requirements;
 »conducting HSI analyses;
 »designing human machine interfaces to provide 
the level of human performance required for 
operations, maintenance, and support, includ -
ing conduct of training;
 »describing the role of HSI experts in document -
ing and reporting the results from tests and 
evaluations.
• Define how collaboration will be performed within 
the HSI team, across program/project integrated 
product teams and with the program/project man -
ager and systems engineer.
• Define how the HSI Plan and the SEMP will be 
kept aligned with each other.• Define responsibility for maintaining and updating 
the HSI Plan through the program/project’s life cycle.
5.3 HSI Issue and Risk Processing
This section describes any HSI-unique processes for iden -
tifying and mitigating human system risks. HSI risks 
should be processed in the same manner and system as 
other program/project risks (technical, programmatic, 
schedule). However, human system risks may only be 
recognized by HSI domain and integration experts. 
Therefore, it may be important to document any unique 
procedures by which the program/project HSI integra -
tor/team identifies, validates, prioritizes, and tracks the 
status of HSI-specific risks through the program/project 
risk management system. Management of HSI risks may 
be deemed the responsibility of the program’s/project’s 
HSI integrator/team in coordination with overall pro -
gram/project risk management.
• Ensure that potential cost, schedule, risk, and trade-
off concerns with the integration of human elements 
(operators, maintainers, ground controllers, etc.) 
with the total system are identified and mitigated.
• Ensure that safety, health, or survivability concerns 
that arise as the system design and implementation 
emerge are identified, tracked, and managed.
• Identify and describe any risks created by limitations 
on the overall program/project HSI effort (time, 
funding, insufficient availability of information, 
availability of expertise, etc.).
• Describe any unique attributes of the process by 
which the HSI integrator/team elevates HSI risks to 
program/project risks.
• Describe any HSI-unique aspects of how human sys -
tem risk mitigation strategies are deemed effective.249
6.0 HSI Implementation
6.1 HSI Implementation Summary
This section summarizes the HSI implementation 
approach by program/project phase. This section shows 
how an HSI strategy for the particular program/project 
is planned to be tactically enabled; i.e., establishment 
of HSI priorities; description of specific activities, tools, 
and products planned to ensure HSI objectives are met; 
application of technology in the achievement of HSI 
objectives; and an HSI risk processing strategy that 
identifies and mitigates technical and schedule concerns 
when they first arise.
6.2 HSI Activities and Products
In this section, map activities, resources, and products 
associated with planned HSI technical implementation 
to each systems engineering phase of the program/project. 
Consideration might be given to mapping the needs and 
products of each HSI domain by program/project phase. 
Examples of HSI activities include analyses, mockup/
prototype human-in-the-loop evaluations, simulation/
modeling, participation in design and design reviews, formative evaluations, technical interchanges, and trade 
studies. Examples of HSI resources include acquisition 
of unique/specific HSI skill sets and domain expertise, 
facilities, equipment, test articles, specific time alloca -
tions, etc.
When activities, products, or risks are tied to life cycle 
reviews, they should include a description of the HSI 
entrance and exit criteria to clearly define the boundaries 
of each phase, as well as resource limitations that may be 
associated with each activity or product (time, funding, 
data availability, etc.). A high-level, summary example 
listing of HSI activities, products, and known risk mit -
igations by life cycle phase is provided in TABLE R.2-1 .
6.3 HSI Plan Update
The HSI Plan should be updated throughout the pro -
gram/project’s life cycle management and systems 
engineering processes at key milestones. Milestones rec -
ommended for HSI Plan updates are listed in appendix 
G of NPR 7123.1, NASA Systems Engineering Processes 
and Requirements.
HSI IMPLEMENTATION
Key Points
• Relate HSI strategic objectives to the technical approaches planned for accomplishing these objectives.
• Overlay HSI milestones—e.g., requirements definition, verification, known trade studies, etc.—on the 
program/project schedule and highlight any inconsistencies, conflicts, or other expected schedule 
challenges.
• Describe how critical HSI key decision points will be dealt with as the program/project progresses 
through its life cycle. Indicate the plan to trace HSI key performance measures through the life cycle; 
i.e., from requirements to human/system functional performance allocations, through design, test, and 
operational readiness assessment.
• Identify HSI-unique systems engineering processes—e.g., verification using human-in-the-loop 
evaluations—that may require special coordination with program/project processes.
• As the system emerges, indicate plans to identify HSI lessons learned from the application of HSI on the 
• Include a high-level summary of the resources required.250
TABLE R.2-1 HSI Activity, Product, or Risk Mitigation by Program/Project Phase
Life-Cycle 
PhasePhase Description Activity, Product, or Risk Mitigation
Pre-Phase A Concept Studies ConOps (Preliminary—to include training, maintenance, logistics, etc.)
Phase A Concept & Technology 
DevelopmentHSI Plan (baseline)
ConOps (initial)
HSI responsible party(ies) and/or team identified before SRR
Develop mockup(s) for HSI evaluations
Crew Workload Evaluation Plan
Functional allocation, crew task lists
Validation of ConOps (planning)
Phase B Preliminary Design & 
Technology CompletionHSI Plan (update)
ConOps (baseline)
Develop engineering-level mockup(s) for HSI evaluations
Define crew environmental and crew health support needs (e.g., aircraft 
flight decks, human space flight missions)
Assess operator interfaces through task analyses (for, e.g., aircraft 
cockpit operations, air traffic management, spacecraft environments, 
mission control for human space flight missions)
Human-in-the-loop usability plan
Human-rating report for PDR
Phase C Final Design & Fabrication HSI Plan (update)
First Article HSI Tests
Human-rating report for CDR
Phase D System Assembly, Integ. & 
Test, Launch & CheckoutHuman-rating report for ORR
Validation of human-centered design activities
Validation of ConOps
Phase E Operations & Sustainment Monitoring of human-centered design performance

Phase F Closeout Lessons learned report
HSI PLAN UPDATES
Key points to be addressed in each update
• Identify the current program/project phase, the publication date of the last iteration of the HSI Plan, and 
the HSI Plan version number. Update the HSI Plan revision history.
• Describe the HSI entrance criteria for the current phase and describe any unfinished work prior to the 
current phase.
• Describe the HSI exit criteria for the current program/project phase and the work that must be 
accomplished to successfully complete the current program/project phase.251
Appendix S:  C oncept of Operations  
Annotated Outline
This Concept of Operations (ConOps) annotated 
outline describes the type and sequence of informa -
tion that should be contained in a ConOps, although 
the exact content and sequence will be a function of 
the type, size, and complexity of the project. The text in italics describes the type of information that would be provided in the associated subsection. Additional subsections should be added as necessary to fully describe the envisioned system.
Cover Page
Table of Contents
1.1 Project Description
This section will provide a brief overview of the devel -
opment activity and system context as delineated in the 
following two subsections.
1.1.1  Background
Summarize the conditions that created the need for the new system. Provide the high-level mission goals and objective of the system operation. Provide the rationale 
for the development of the system.
1.1.2  Assumptions and Constraints
State the basic assumptions and constraints in the devel -
opment of the concept. For example, that some technol -
ogy will be matured enough by the time the system is ready to be fielded, or that the system has to be provided 
by a certain date in order to accomplish the mission.
1.2 Overview of the Envisioned System
This section provides an executive summary overview of the envisioned system. A more detailed description will be provided in Section 3.0
1.2.1  Overview
This subsection provides a high-level overview of the sys -
tem and its operation. Pictorials, graphics, videos, mod -
els, or other means may be used to provide this basic 
understanding of the concept.
1.2.2  System Scope
This section gives an estimate of the size and complex -
ity of the system. It defines the system’s external inter -
faces and enabling systems. It describes what the project will encompass and what will lie outside of the project’s 
development.
This section lists all the documents, models, standards or other material that are applicable and some or all of which will form part of the requirements of the project.
This section provides supplemental information that might be useful in understanding the system or its scenarios.252
NASA SYSTEMS ENGINEERING HANDBOOKAppendix S: Concept of OperationsAnnotated Outline 
3.0 Description of Envisioned 
System
This section provides a more detailed description of the 
envisioned system and its operation as contained in the 
following subsections.
3.1  Needs, Goals and Objectives of 
Envisioned System
This section describes the needs, goals, and objectives as 
expectations for the system capabilities, behavior, and oper -
ations. It may also point to a separate document or model 
that contains the current up-to-date agreed-to expectations.
3.2  Overview of System and Key 
Elements
This section describes at a functional level the vari -
ous elements that will make up the system, including 
the users and operators. These descriptions should be 
implementation free; that is, not specific to any imple -
mentation or design but rather a general description of 
what the system and its elements will be expected to do. 
Graphics, pictorials, videos, and models may be used to 
aid this description.
3.3 Interfaces
This section describes the interfaces of the system with 
any other systems that are external to the project. It may 
also include high-level interfaces between the major 
envisioned elements of the system. Interfaces may include 
mechanical, electrical, human user/operator, fluid, 
radio frequency, data, or other types of interactions.
3.4 Modes of Operations
This section describes the various modes or configura -
tions that the system may need in order to accomplish 
its intended purpose throughout its life cycle. This may 
include modes needed in the development of the sys -
tem, such as for testing or training, as well as various 
modes that will be needed during it operational and 
disposal  phases.3.5 Proposed Capabilities
This section describes the various capabilities that the 
envisioned system will provide. These capabilities cover 
the entire life cycle of the system’s operation, including 
special capabilities needed for the verification/validation 
of the system, its capabilities during its intended oper -
ations, and any special capabilities needed during the 
decommissioning or disposal process.
4.0 Physical Environment
This section should describe the environment that the 
system will be expected to perform in throughout its 
life cycle, including integration, tests, and transpor -
tation. This may include expected and off-nominal 
temperatures, pressures, radiation, winds, and other 
atmospheric, space, or aquatic conditions. A description 
of whether the system needs to operate, tolerate with 
degraded performance, or just survive in these condi -
tions should be noted.
5.0 Support Environment
This section describes how the envisioned system will be 
supported after being fielded. This includes how opera -
tional planning will be performed and how command -
ing or other uploads will be determined and provided, 
as required. Discussions may include how the envi -
sioned system would be maintained, repaired, replaced, 
it’s sparing philosophy, and how future upgrades may be 
performed. It may also include assumptions on the level 
of continued support from the design teams.
6.0 Operational Scenarios, 
Use Cases and/or Design 
Reference Missions
This section takes key scenarios, use cases, or DRM and 
discusses what the envisioned system provides or how 
it functions throughout that single-thread timeline. 253
The number of scenarios, use cases, or DRMs discussed 
should cover both nominal and off-nominal conditions 
and cover all expected functions and capabilities. A good 
practice is to label each of these scenarios to facilitate 
requirements traceability; e.g., [DRM-0100], [DRM-
0200], etc.
6.1 Nominal Conditions
These scenarios, use cases, or DRMs cover how the envi -
sioned system will operate under normal circumstances 
where there are no problems or anomalies taking place.
6.2 Off-Nominal Conditions
These scenarios cover cases where some condition has 
occurred that will need the system to perform in a way 
that is different from normal. This would cover failures, 
low performance, unexpected environmental conditions, 
or operator errors. These scenarios should reveal any 
additional capabilities or safeguards that are needed in 
7.0 Impact Considerations
This section describes the potential impacts, both positive 
and negative, on the environment and other areas.
7.1 Environmental Impacts
Describes how the envisioned system could impact the 
environment of the local area, state, country, world -
wide, space, and other planetary bodies as appropriate 
for the systems intended purpose. This includes the pos -
sibility of the generation of any orbital debris, potential 
contamination of other planetary bodies or atmosphere, 
and generation of hazardous wastes that will need dis -
posal on earth and other factors. Impacts should cover 
the entire life cycle of the system from development 
through disposal.7.2 Organizational Impacts
Describes how the envisioned system could impact existing or 
future organizational aspects. This would include the need 
for hiring specialists or operators, specialized or widespread 
training or retraining, and use of multiple organizations.
7.3 Scientific/Technical Impacts
This subsection describes the anticipated scientific or 
technical impact of a successful mission or deploy -
ment, what scientific questions will be answered, what 
knowledge gaps will be filled, and what services will be 
provided. If the purpose of this system is to improve oper -
ations or logistics instead of science, describe the antici -
pated impact of the system in those terms.
8.0 Risks and Potential Issues
This section describes any risks and potential issues asso -
ciated with the development, operations or disposal of 
the envisioned system. Also includes concerns/risks with 
the project schedule, staffing support, or implementation 
approach. Allocate subsections as needed for each risk 
or issue consideration. Pay special attention to closeout

or issue consideration. Pay special attention to closeout 
issues at the end of the project.
This part lists each acronym used in the ConOps and 
spells it out.
Appendix B: Glossary of Terms
The part lists key terms used in the ConOps and provides 
a description of their meaning.254
Appendix T: Systems Engineering in Phase E
T.1 Overview
In general, normal Phase E activities reflect a reduced 
emphasis on system design processes but a continued focus on product realization and technical manage -
ment. Product realization process execution in Phase E takes the form of continued mission plan generation (and update), response to changing flight conditions (and occurrence of in-flight anomalies), and update of mission operations techniques, procedures, and guidelines based on operational experience gained. 
Technical management processes ensure that appro -
priate rigor and risk management practices are applied 
in the execution of the product realization processes.
Successful Phase E execution requires the prior estab -
lishment of mission operations capabilities in four 
(4) distinct categories: tools, processes, products, and trained personnel. These capabilities may be developed as separate entities, but need to be fused together in Phase E to form an end-to-end opera -
tional capability.
Although systems engineering activities and pro -
cesses are constrained throughout the entire project 
life cycle, additional pressures exist in Phase E:
• Increased resource constraints:  Even when 
additional funding or staffing can be secured, building new capabilities or training new person -
nel may require more time or effort than is avail -
able. Project budget and staffing profiles generally decrease at or before entry into Phase E, and the remaining personnel are typically focused on mis-sion execution.• Unforgiving schedule:  Unlike pre-flight test 
activities, it may be difficult or even impossible to pause mission execution to deal with technical 
issues of a spacecraft in operation. It is typically 
difficult or impossible to truly pause mission exe -
cution after launch.
These factors must be addressed when consider -
ing activities that introduce change and risk during 
Phase E.
NOTE:
 When significant hardware or software 
changes are required in Phase E, the logical decom -
position process may more closely resemble that 
exercised in earlier project phases. In such cases, it may be more appropriate to identify the modifi -
cation as a new project executing in parallel—and coordinated with—the operating project.
T.2 Transition from Development 
to Operations
An effective transition from development to opera -
tions phases requires prior planning and coordina -
tion among stakeholders. This planning should focus 
not only on the effective transition of hardware and 
software systems into service but also on the effec -
tive transfer of knowledge, skills, experience, and processes into roles that support the needs of flight operations.
Development phase activities need to clearly and 
concisely document system knowledge in the form 255
NASA SYSTEMS ENGINEERING HANDBOOKAppendix T: Systems Engineering in Phase E
of operational techniques, characteristics, limits, 
and constraints—these are key inputs used by flight 
operations personnel in building operations tools 
and techniques. Phase D Integration and Test (I&T) 
activities share many common needs with Phase E 
operations activities. Without prior planning and 
agreement, however, similar products used in these 
two phases may be formatted so differently that one 
set cannot be used for both purposes. The associated 
product duplication is often unexpected and results 
in increased cost and schedule risk. Instead, system 
engineers should identify opportunities for product 
reuse early in the development process and establish 
common standards, formats, and content expecta -
tions to enable transition and reuse.
Similarly, the transfer of skills and experience should 
be managed through careful planning and placement 
of key personnel. In some cases, key design, integra -
tion, and test personnel may be transitioned into the 
mission operations team roles. In other cases, dedi -
cated mission operations personnel may be assigned 
to shadow or assist other teams during Phase A–D 
activities. In both cases, assignees bring knowledge, 
skills, and experience into the flight operations envi -
ronment. Management of this transition process can, 
however, be complex as these personnel may be con -
sidered key to both ongoing I&T and preparation for 
upcoming operations. Careful and early planning of 
personnel assignments and transitions is key to suc -
cess in transferring skills and experience.
T.3 System Engineering 
Processes in Phase E
T.3.1  System Design Processes
In general, system design processes are complete well 
before the start of Phase E. However, events during 
operations may require that these processes be revis -
ited in Phase E.T.3.1.1 Stakeholder Expectations Definition
Stakeholder expectations should have been identi -
fied during development phase activities, including 
the definition of operations concepts and design ref -
erence missions. Central to this definition is a con -
sensus on mission success criteria and the priority of 
all intended operations. The mission operations plan 
should state and address these stakeholder expec -
tations with regard to risk management practices, 
planning flexibility and frequency of opportunities 
to update the plan, time to respond and time/scope 
of status communication, and other key parameters 
of mission execution. Additional detail in the form 
of operational guidelines and constraints should be 
incorporated in mission operations procedures and 
flight rules.
The Operations Readiness Review (ORR) should 
confirm that stakeholders accept the mission opera -
tions plan and operations implementation products.
However, it is possible for events in Phase E to require 
a reassessment of stakeholder expectations. Significant 
in-flight anomalies or scientific discoveries during 
flight operations may change the nature and goals of 
a mission. Mission systems engineers, mission oper -
ations managers, and program management need to 
remain engaged with stakeholders throughout Phase 
E to identify potential changes in expectations and to 
manage the acceptance or rejection of such changes 
during operations.
T.3.1.2 Technical Requirements Definition
New technical requirements and changes to existing 
requirements may be identified during operations as 
a result of:
• New understanding of system characteristics 
through flight experience;
• The occurrence of in-flight anomalies; or256
• Changing mission goals or parameters (such as 
mission extension).
These changes or additions are generally handled as 
change requests to an operations baseline already under 
configuration management and possibly in use as part 
of ongoing flight operations. Such changes are more 
commonly directed to the ground segment or opera -
tions products (operational constraints, procedures, 
etc.). Flight software changes may also be considered, 
but flight hardware changes for anything other than 
human-tended spacecraft are rarely possible.
Technical requirement change review can be more 
challenging in Phase E as fewer resources are avail -
able to perform comprehensive review. Early and 
close involvement of Safety and Mission Assurance 
(SMA) representatives can be key in ensuring that 
proposed changes are appropriate and within the 
project’s allowable risk tolerance.
T.3.1.3 Logical Decomposition
In general, logical decomposition of mission oper -
ations functions is performed during development 
phases. Additional logical decomposition during 
operations is more often applied to the operations 
products: procedures, user interfaces, and operational 
constraints. The authors and users of these products 
are often the most qualified people to judge the 
appropriate decomposition of new or changed func -
tionality as a series of procedures or similar products.
T.3.1.4 Design Solution Definition
Similar to logical decomposition, design solution 
definition tasks may be better addressed by those who 
develop and use the products. Minor modifications 
may be handled entirely within an operations team 
(with internal reviews), while larger changes or addi -
tions may warrant the involvement of program-level 
system engineers and Safety and Mission Assurance 
(SMA) personnel.Scarcity of time and resources during Phase E can 
make implementation of these design solutions chal -
lenging. The design solution needs to take into account 
the availability of and constraints to resources.
T.3.1.5 Product Implementation
Personnel who implement mission operations prod -
ucts such as procedures and spacecraft command 
scripts should be trained and certified to the appro -

priate level of skill as defined by the project. Processes 
governing the update and creation of operations 
products should be in place and exercised prior to 
Phase E.
T.3.2  Product Realization Processes
Product realization processes in Phase E are typically 
executed by Configuration Management (CM) and 
test personnel. It is common for these people to be 
“shared resources;” i.e., personnel who fulfil other 
roles in addition to CM and test roles.
T.3.2.1 Product Integration
Product integration in Phase E generally involves bring -
ing together multiple operations products—some pre -
existing and others new or modified—into a proposed 
update to the baseline mission operations capability.
The degree to which a set of products is integrated may 
vary based on the size and complexity of the project. 
Small projects may define a baseline—and update to 
that baseline—that spans the entire set of all opera -
tions products. Larger or more complex projects may 
choose to create logical baseline subsets divided along 
practical boundaries. In a geographically disperse set 
of separate mission operations Centers, for example, 
each Center may be initially integrated as a separate 
product. Similarly, the different functions within a 
single large control Center—planning, flight dynam -
ics, command and control, etc.—may be established 
as separately baselined products. Ultimately, however, 257
some method needs to be established to ensure that 
the product realization processes identify and assess 
all potential impacts of system changes.
T.3.2.2 Product Verification
Product verification in Phase E generally takes the 
form of unit tests of tools, data sets, procedures, and 
other items under simulated conditions. Such “thread 
tests” may exercise single specific tasks or functions. 
The fidelity of simulation required for verification 
varies with the nature and criticality of the product. 
Key characteristics to consider include:
• Runtime:  Verification of products during flight 
operations may be significantly time constrained. 
Greater simulation fidelity can result in slower 
simulation performance. This slower performance 
may be acceptable for some verification activities 
but may be too constraining for others.
• Level of detail:  Testing of simple plans and pro -
cedures may not require high-fidelity simulation 
of a system’s dynamics. For example, simple state 
change processes may be tested on relatively 
low-fidelity simulations. However, operational 
activities that involve dynamic system attributes – 
such as changes in pressure, temperature, or other 
physical properties may require testing with much 
higher-fidelity simulations.
• Level of integration:  Some operations may impact 
only a single subsystem, while others can affect 
multiple systems or even the entire spacecraft.
• Environmental effects:  Some operations products 
and procedures may be highly sensitive to envi -
ronmental conditions, while others may not. For 
example, event sequences for atmospheric entry 
and deceleration may require accurate weather 
data. In contrast, simple system reconfiguration procedures may not be impacted by environmen -
tal conditions at all.
T.3.2.3 Product Validation
Product validation is generally executed through the 
use of products in integrated operational scenarios 
such as mission simulations, operational readiness 
tests, and/or spacecraft end-to-end tests. In these 
environments, a collection of products is used by a 
team of operators to simulate an operational activ -
ity or set of activities such as launch, activation, ren -
dezvous, science operations, or Entry, Descent, and 
Landing (EDL). The integration of multiple team 
members and operations products provides the con -
text necessary to determine if the product is appropri -
ate and meets the true operations need.
T.3.2.4 Product Transition
Transition of new operational capabilities in Phase 
E is generally overseen by the mission operations 
manager or a Configuration Control Board (CCB) 
chaired by the mission operations manager or the 
project manager.
Proper transition management includes the inspec -
tion of product test (verification and validation) 
results as well as the readiness of the currently oper -
ating operations system to accept changes. Transition 
during Phase E can be particularly challenging as the 
personnel using these capabilities also need to change 
techniques, daily practices, or other behaviors as a 
result. Careful attention should be paid to planned 
operations, such as spacecraft maneuvers or other 
mission critical events and risks associated with per -
forming product transition at times near such events.
T.3.3   Technical Management 
Processes
Technical management processes are generally a 
shared responsibility of the project manager and 258
the mission operations manager. Clear agreement 
between these two parties is essential in ensuring that 
Phase E efforts are managed effectively.
T.3.3.1 Technical Planning
Technical planning in Phase E generally focuses 
on the management of scarce product develop -
ment resources during mission execution. Key 
decision-makers, including the mission operations 
manager and lower operations team leads, need to 
review the benefits of a change against the resource 
cost to implement changes. Many resources are 
shared in Phase E – for example, product developers 
may also serve other real-time operations roles– and 
the additional workload placed on these resources 
should be viewed as a risk to be mitigated during 
operations.
T.3.3.2 Requirements Management
Requirements management during Phase E is simi -
lar in nature to pre-Phase E efforts. Although some 
streamlining may be implemented to reduce process 
overhead in Phase E, the core need to review and val -
idate requirements remains. As most Phase E changes 
are derived from a clearly demonstrated need, pro -
gram management may reduce or waive the need 
for complete requirements traceability analysis and 
documentation.
T.3.3.3 Interface Management
It is relatively uncommon for interfaces to change in 
Phase E, but this can occur when a software tool is 
modified or a new need is uncovered. Interface defi -
nitions should be managed in a manner similar to 
that used in other project phases.
T.3.3.4 Technical Risk Management
Managing technical risks during operations can be 
more challenging during Phase E than during other 
phases. New risks discovered during operations may be the result of system failures or changes in the sur -
rounding environment. Where additional time may 
be available to assess and mitigate risk in other proj -
ect phases, the nature of flight operations may limit 
the time over which risk management can be exe -
cuted. For this reason, every project should develop a 
formal process for handling anomalies and managing 
risk during operations. This process should be exer -
cised before flight, and decision-makers should be 
well versed in the process details.
T.3.3.5 Configuration Management
Effective and efficient Configuration Management 
(CM) is essential during operations. Critical oper -
ations materials, including procedures, plans, flight 
datasets, and technical reference material need to 
be secure, up to date, and easily accessed by those 
who make and enact mission critical decisions. CM 
systems—in their intended flight configuration—
should be exercised as part of operational readiness 
tests to ensure that the systems, processes, and par -
ticipants are flight-ready.
Access to such operations products is generally 
time-critical, and CM systems supporting that access 
should be managed accordingly. Scheduled mainte -
nance or other “downtime” periods should be coor -
dinated with flight operations plans to minimize 
the risk of data being inaccessible during critical 
activities.
T.3.3.6 Technical Data Management
Tools, procedures, and other infrastructure for 
Technical Data Management must be baselined, 
implemented, and verified prior to flight operations. 
Changes to these capabilities are rarely made during 
Phase E due to the high risk of data loss or reduc -
tion in operations efficiency when changing during 
operations.259
Mandatory Technical Data Management infrastruc -
ture changes, when they occur, should be carefully 
reviewed by those who interact with the data on a 
regular basis. This includes not only operations per -
sonnel, but also engineering and science customers of 
that data.
T.3.3.7 Technical Assessment
Formal technical assessments during Phase E are typ -
ically focused on the upcoming execution of a spe -
cific operational activity such as launch, orbit entry, 
or decommissioning. Reviews executed while flight 
operations are in progress should be scoped to answer

that data.
operations are in progress should be scoped to answer 
critical questions while not overburdening the project 
or operations team.
Technical Performance Measures (TPMs) in Phase E 
may differ significantly from those in other project phases. Phase E TPMs may focus on the accomplish -
ment of mission events, the performance of the sys -
tem in operation, and the ability of the operations 
team to support upcoming events.
T.3.3.8 Decision Analysis
The Phase E Decision Analysis Process is similar to 
that in other project phases but may emphasize dif -
ferent criteria. For example, the ability to change a 
schedule may be limited by the absolute timing of 
events such as an orbit entry or landing on a plan -
etary surface. Cost trades may be more constrained 
by the inability to add trained personnel to support 
an activity. Technical trades may be limited by the 
inability to modify hardware in operation.260
References Cited
This appendix contains references that were cited in 
the sections of the handbook.
Preface
NPR 7123.1, Systems Engineering Processes and 
NASA Chief Engineer and the NASA Integrated 
Action Team (NIAT) report, Enhancing Mission 
Success – A Framework for the Future , December 
21, 2000. Authors: McBrayer, Robert O and 
Thomas, Dale, NASA Marshall Space Flight Center, Huntsville, AL United States.
NASA. Columbia Accident Investigation Board 
(CAIB) Report , 6 volumes: Aug. 26, Oct. 2003. 
http://www.nasa.gov/columbia/caib/html/report.
html
NASA. Diaz Report, A Renewed Commitment to 
Excellence : An Assessment of the NASA Agency-
wide Applicability of the Columbia Accident 
Investigation Board Report , January 30, 2004. 
Mr. Al Diaz, Director, Goddard Space Flight 
Center, and team.
International Organization for Standardization 
(ISO) 9000:2015, Quality management sys -
tems – Fundamentals and vocabulary . Geneva: 
International Organization for Standardization, 2015.Section 1.1  P urpose
NPR 7123.1. Systems Engineering Processes and 
Section 1.2  S cope and Depth
NASA Office of Chief Information Officer (OCIO), 
Information Technology Systems Engineering Handbook Version 2.0
NASA-HDBK-2203, NASA Software Engineering 
Handbook  (February 28, 2013)
Section 2.0  F undamentals of Systems 
EngineeringNPR 7120.5, NASA Space Flight Program and 
Project Management Requirements
NPR 7120.7, NASA Information Technology and 
Institutional Infrastructure Program and Project Management Requirements
NPR 7120.8, NASA Research and Technology 
Program and Project Management Requirements
NPR 7123.1, NASA Systems Engineering Processes 
NASA Engineering Network (NEN) Systems 
Engineering Community of Practice (SECoP), located at 
https://nen.nasa.gov/web/se
Griffin, Michael D., NASA Administrator. 
“System Engineering and the Two Cultures 261
NASA SYSTEMS ENGINEERING HANDBOOKReferences Cited
of Engineering.” Boeing Lecture, Purdue 
University, March 28, 2007.
Rechtin, Eberhardt. Systems Architecting of 
Organizations: Why Eagles Can’t Swim . Boca 
Raton: CRC Press, 2000.
Section 2.1 The Common Technical 
Society of Automotive Engineers (SAE) and the 
European Association of Aerospace Industries 
(EAAI). AS9100C Quality Management Systems 
(QMS) – Requirements for Aviation, Space, and 
Defense Organizations  Revision C: January 15, 
2009.
Section 2.3 Example of Using the SE 
Engine
NPD 1001.0, 2006 NASA Strategic Plan
NPR 7120.5, NASA Space Flight Program and 
Section 2.5  Cost Effectiveness 
Department of Defense (DOD) Defense Acquisition 
University (DAU). Systems Engineering 
Fundamentals Guide . Fort Belvoir, VA, 2001.
INCOSE-TP-2003-002-04, Systems Engineering 
Handbook: A Guide for System Life Cycle Processes 
and Activities , Version 4, edited by Walden, 
David D., et al., 2015
Section 2.6 Human Systems Integration 
Project Management RequirementsNPR 7123.1, NASA Systems Engineering Processes 
Section 3.0 NASA Program/Project Life 
Cycle
Program and Project Management 
NASA Office of the Chief Information Officer 
(OCIO), Information Technology Systems 
Engineering Handbook  Version 2.0
NASA/SP-2014-3705, NASA Space Flight Program 
and Project Management Handbook
Section 3.1  Program Formulation
Institutional Infrastructure Program and Project 
Management Requirements
Section 3.2  Program Implementation
and Requirements262
Section 3.3 Project Pre-Phase A: Concept 
Studies
Section 3.4 Project Phase A: Concept and 
Technology Development
NPD 1001.0, 2014 NASA Strategic Plan
NPR 2810.1, Security of Information Technology
NPR 7150.2, NASA Software Engineering 
NASA-STD-8719.14, Handbook for Limiting Orbital 
Debris . Rev A with Change 1. December 8, 
2011.
National Institute of Standards and Technology 
(NIST), Federal Information Processing 
Standard Publication (FIPS PUB) 199, 
Standards for Security Categorization of Federal 
Information and Information Systems , February 
2004.
Section 3.5 Project Phase B: Preliminary 
Design and Technology Completion
and RequirementsSection 3.6 Project Phase C: Final Design 
and Fabrication
Section 3.7 Project Phase D: System 
Assembly, Integration and Test, Launch
(OCIO),  Information Technology Systems 
Engineering Handbook Version 2.0
Section 3.8 Project Phase E: Operations 
and Sustainment
Section 3.9 Project Phase F: Closeout
NPD 8010.3, Notification of Intent to 
Decommission or Terminate Operating Space 
Systems and Terminate Missions
NPR 8715.6, NASA Procedural Requirements for 
Limiting Orbital Debris263
Section 3.10 Funding: The Budget Cycle
NASA’s Financial Management Requirements (FMR)  
Volume 4
Section 3.11  Tailoring and Customization 
NPR 8705.4, Risk Classification for NASA Payloads
Engineering Community of Practice (SECoP), 
located at https://nen.nasa.gov/web/se
Section 4.1  Stakeholder Expectations 
NASA Science Mission Directorate strategic plansPresidential Policy Directive PPD-4 (2010), 
National Space Policy
Presidential Policy Directive PPD-21 (2013), Critical 
Infrastructure Security and Resilience
Ball, Robert E. (Naval Postgraduate School), The 
Fundamentals of Aircraft Combat Survivability 
Analysis and Design , 2nd Edition, AIAA 
Education Series, 2003
Larson (Wiley J.), Kirkpatrick, Sellers, Thomas, 
and Verma. Applied Space Systems Engineering: 
A Practical Approach to Achieving Technical 
Baselines.  2nd Edition, Boston, MA: McGraw-
Hill Learning Solutions, CEI Publications, 
2009.
Section 4.2  Technical Requirements 
NPR 7120.10, Technical Standards for NASA

2009.
NPR 7120.10, Technical Standards for NASA 
Programs and Projects
NPR 8705.2, Human-Rating Requirements for 
Space Systems
NPR 8715.3, NASA General Safety Program 
NASA-STD-3001, NASA Space Flight Human 
System Standard  – 2 volumes
NASA-STD-8719.13, Software Safety Standard , Rev 
C. Washington, DC, May 7, 2013.
NA SA /SP-2010 -3407, Human Integration Design 
Handbook (HIDH)264
Section 4.3  Logical Decomposition
Department of Defense (DOD) Architecture 
Framework (DODAF)  Version 2.02 Change 1, 
Januar y 2015
Institute of Electrical and Electronics Engineers 
(IEEE) STD 610.12-1990, IEEE Standard 
Glossary of Software Engineering Terminology . 
Reaffirmed 2002. Superseded by ISO/IEC/
IEEE 24765:2010, Systems and Software 
Engineering – Vocabulary
Section 4.4 Design Solution Definition
NPD 8730.5, NASA Quality Assurance Program 
Policy
NPR 8735.2, Management of Government Quality 
Assurance Functions for NASA Contracts
NASA-HDBK-1002, Fault Management (FM) 
Handbook , Draft 2, April 2012.
NASA-STD-8729.1, Planning, Developing, and 
Maintaining an Effective Reliability and 
Maintainability (R&M) Program . Washington, 
DC, December 1, 1998.
Code of Federal Regulations (CFR), Title 48 – 
Federal Acquisition Regulation (FAR) System, 
Part 46.4 Government Contract Quality 
Assurance (48 CFR 46.4)
International Organization for Standardization, ISO 
9001:2015 Quality Management Systems (QMS)
Society of Automotive Engineers and the 
European Association of Aerospace Industries. 
AS9100C Quality Management Systems (QMS)—Requirements for Aviation, Space, and 
Defense Organizations  Revision C: 2009-01-15
Blanchard, Benjamin S., System Engineering 
Management . 4th Edition, Hoboken, NJ: John 
Wiley & Sons, Inc., 2008
Section 5.1  Product Implementation
NASA Engineering Network (NEN) V&V 
Community of Practice, located at https://nen.
nasa.gov/web/se
American Institute of Aeronautics and Astronautics 
(AIAA) G-118-2006e. AIAA Guide for 
Managing the Use of Commercial Off the Shelf 
(COTS) Software Components for Mission-
Critical Systems . Reston, VA, 2006
Section 5.2  Product Integration
NASA Lyndon B. Johnson Space Center (JSC-
60576), National Space Transportation System 
(NSTS), Space Shuttle Program, Transition 
Management Plan, May 9, 2007
Section 5.3  Product Verification
and Requirements265
NASA-STD-7009, Standard for Models and 
Simulations . Washington, DC, October 18, 
2013
NASA GSFC-STD-7000, Goddard Technical 
Standard: General Environmental Verification 
Standard (GEVS) for GSFC Flight Programs and 
Projects . Goddard Space Flight Center. April 
2005
Department of Defense (DOD). MIL-STD-1540D, 
Product Verification Requirements for Launch, 
Upper Stage, and Space Vehicles . January 15, 
1999
Section 5.4  Product Validation
NPD 7120.4, NASA Engineering and Program/
Project Management Policy
Section 5.5  Product Transition
(The) National Environmental Policy Act of 1969 
(NEPA). See 42 U.S.C. 4321-4347. https://ceq.
doe.gov/welcome.html
Section 6.1 Technical Planning
NPD 7120.6, Knowledge Policy on Programs and 
Projects
NASA-SP-2010-3403, NASA Schedule Management 
HandbookNASA-SP-2010-3404, NASA Work Breakdown 
Structure Handbook
NASA Cost Estimating Handbook (CEH) , Version 4, 
Februar y 2015.
DOD. MIL-STD-881C, Work Breakdown Structure 
(WBS) for Defense Materiel Items . Washington, 
DC, October 3, 2011.
(IEEE) STD 1220-2005. IEEE Standard for 
Application and Management of the Systems 
Engineering Process , Washington, DC, 2005.
Office of Management and Budget (OMB) Circular 
A-94, “Guidelines and Discount Rates for 
Benefit-Cost Analysis of Federal Programs” 
(10/29/1992)
Joint (cost and schedule) Confidence Level (JCL). 
Frequently asked questions (FAQs) can be found 
at: http://www.nasa.gov/pdf/394931main_JCL_
FAQ_10_12_09.pdf
The U. S. Chemical Safety Board (CSB) case study 
reports on mishaps found at: http://www.csb.gov/
Section 6.3 Interface Management
Section 6.4 Technical Risk Management
NASA/SP-2010-576, NASA Risk-Informed Decision 
Making Handbook266
NASA/SP-2011-3421, Probabilistic Risk Assessment 
Procedures Guide for NASA Managers and 
Practitioners
NASA/SP-2011-3422, NASA Risk Management 
Handbook
Code of Federal Regulations (CFR) Title 22 – 
Foreign Relations, Parts 120-130 Department of 
State: International Traffic in Arms Regulations 
(ITAR) (22 CFR 120-130). Implements 22 
U.S.C. 2778 of the Arms Export Control Act 
(AECA) of 1976 and Executive Order 13637, 
“Administration of Reformed Export Controls,” 
March 8, 2013
Section 6.5  Configuration Management
http://www.nasa.gov/columbia/caib/html/report.html
NASA. NOAA N-Prime Mishap Investigation Final 
Report , Sept. 13, 2004 http://www.nasa.gov/pdf/
65776main_noaa_np_mishap.pdf
SAE International (SAE)/Electronic Industries 
Alliance (EIA) 649B-2011, Configuration 
Management Standard (Aerospace Sector)  April 1, 
2011
American National Standards Institute (ANSI)/
Electronic Industries Alliance (EIA). ANSI/
EIA-649, National Consensus Standard for 
Configuration Management , 1998–1999
Section 6.6 Technical Data Management
NPR 1441.1, NASA Records Retention SchedulesNPR 1600.1, NASA Security Program Procedural 
NID 1600.55, Sensitive But Unclassified (SBU) 
Controlled Information
NASA Form (NF) 1686, NASA Scientific and 
Technical Document Availability Authorization 
(DAA) for Administratively Controlled 
Information.
The Invention Secrecy Act of 1951, 35 U.S.C. 
§181–§188. Secrecy of Certain Inventions and 
Filing Applications in Foreign Country; §181 – 
Secrecy of Certain Inventions and Withholding 
of Patent.
Code of Federal Regulations (CFR) Title 37 – 
Patents, Trademarks, and Copyrights; Part 5 
Secrecy of Certain Inventions and Licenses 
to Export and File Applications in Foreign 
Countries; Part 5.2 Secrecy Order. (37 CFR 5.2)
Section 6.7  Technical Assessment
NPR 1080.1, Requirements for the Conduct of 
NASA Research and Technology (R&T)267
NPR 8705.6, Safety and Mission Assurance (SMA) 
Audits, Reviews, and Assessments
Handbook . February 28, 2013
NASA/SP-2012-599, NASA’s Earned Value 
Management (EVM) Implementation Handbook
NASA Federal Acquisition Regulation (FAR) 
Supplement (NFS) 1834.201, Earned Value 
Management System Policy.
NASA EVM website http://evm.nasa.gov/index.html
NASA Engineering Network (NEN) EVM 
Community of Practice located at https://nen.
nasa.gov/web/pm/evm
Engineering Community of Practice (SECoP) 
under Tools and Methods at https://nen.nasa.gov/web/se/tools/  and then NASA Tools & 
Methods
American National Standards Institute/Electronic 
Industries Alliance (ANSI-EIA), Standard 
748-C Earned Value Management Systems . 
March, 2013.
International Council on Systems Engineering 
(INCOSE). INCOSE-TP-2003-020-01,

Methods
(INCOSE). INCOSE-TP-2003-020-01, 
Technical Measurement , Version 1.0, 27 
December 2005. Prepared by Garry J. Roedler 
(Lockheed Martin) and Cheryl Jones (U.S. 
Army).
Section 6.8  Decision Analysis
Brughelli, Kevin (Lockheed Martin), Deborah 
Carstens (Florida Institute of Technology), 
and Tim Barth (Kennedy Space Center), 
“Simulation Model Analysis Techniques,” 
Lockheed Martin presentation to KSC, 
November 2003
Saaty, Thomas L. The Analytic Hierarchy Process . 
New York: McGraw-Hill, 1980
NPR 2210.1, Release of NASA Software
Project Management Requirements268
(ISO). ISO/IEC/IEEE 42010:2011. Systems and 
Software Engineering – Architecture Description . 
Geneva: International Organization for 
Standardization, 2011. ( http://www.iso-architec -
ture.org/ieee-1471/index.html )
Avizienis, A., J.C. Laprie, B. Randell, C. Landwehr, 
“Basic concepts and taxonomy of dependable 
and secure computing,” IEEE Transactions on 
Dependable and Secure Computing  1 (1), 11–33, 
2004
Appendix F: Functional, Timing, and State 
Analysis
NASA Reference Publication 1370, Training 
Manual for Elements of Interface Definition and 
Control . 1997
Defense Acquisition University. Systems Engineering 
Fundamentals Guide . Fort Belvoir, VA, 2001
Buede, Dennis. The Engineering Design of Systems: 
Models and Methods . New York: Wiley & Sons, 
2000Long, James E.  Relationships Between Common 
Graphical Representations in Systems Engineering.  
Vienna, VA: Vitech Corporation, 2002
Sage, Andrew, and William Rouse. The Handbook 
of Systems Engineering and Management . New 
York: Wiley & Sons, 1999
Appendix G:  Technology Assessment/
Insertion
Federal Highway Administration and CalTrans, 
Systems Engineering Guidebook for ITS , Version 
2.0. Washington, DC: U.S. Department of 
Transportation, 2007
Appendix K:  Technical Plans
2011269
Appendix N: Guidance on Technical Peer 
Reviews/Inspections
NASA Langley Research Center (LARC), 
Instructional Handbook for Formal Inspections . 
http://sw-eng.larc.nasa.gov/files/2013/05/
Instructional-Handbook-for-Formal-Inspections.
pdf
NASA Langley Research Center (LaRC) Procedural 
Requirements (LPR) 5000.2 Procurement 
Initiator’s GuideNASA Langley Research Center (LaRC) Guidance 
on System and Software Metrics for Performance-
Based Contracting  sites-e.larc.nasa.gov/sweng/
files/2013/05/Guidance_on_Metrics_for_PBC_
R1V01.doc
NASA-STD-3001, Space Flight Human-System 
Standard , Volume 2: Human Factors, 
Habitability, and Environmental Health, 
Section 3.5 [V2 3005], “Human-Centered 
Design Process.” February 10, 2015270
Bibliography
The bibliography contains sources cited in sections of 
the document and additional sources for developing the material in the document.
AIAA American Institute of Aeronautics and 
Astronautics
ANSI American National Standards Institute
CCSDS Consultative Committee for Space Data Systems
CFR (U.S.) Code of Federal Regulations
COSPAR The Committee on Space Research
GEIA Government Electronics Information Technology Association
IEEE Institute of Electrical and Electronics Engineers
NIST National Institute of Standards and Technology
SAE Society of Automotive Engineers
TOR Technical Operating Report
U.S.C. United States CodeA
Adams, R. J., et al. Software Development Standard 
for Space Systems, Aerospace Corporation Report  
No. TOR-2004(3909)3537, Revision B. March 
11, 2005. Prepared for the U.S. Air Force.
AIAA G-118-2006e, AIAA Guide for Managing the 
Use of Commercial Off the Shelf (COTS) Software Components for Mission-Critical Systems , Reston, 
VA, 2006
AIAA S-120-2006, Mass Properties Control for Space 
Systems . Reston, VA, 2006
AIAA S-122-2007, Electrical Power Systems for 
Unmanned Spacecraft , Reston, VA, 2007
ANSI/AIAA G-043-1992, Guide for the Preparation 
of Operational Concept Documents , Washington, 
DC, 1992
ANSI/EIA-632, Processes for Engineering a System , 
Arlington, VA, 1999
ANSI/EIA-649, National Consensus Standard for 
Configuration Management , 1998-1999
ANSI/GEIA-649, National Consensus Standard for 
Configuration Management , National Defense 
Industrial Association (NDIA), Arlington, VA 1998
ANSI/EIA-748-C Standard: Earned Value 
Management Systems , March, 2013271
NASA SYSTEMS ENGINEERING HANDBOOKBibliography
ANSI/GEIA GEIA-859, Data Management , 
National Defense Industrial Association 
(NDIA), Arlington, VA 2004
ANSI/IEEE STD 1042. IEEE Guide to Software 
Configuration Management . Washington, DC, 
1987
Architecture Analysis & Design Language (AADL): 
https://wiki.sei.cmu.edu/aadl/index.php/Main_Page
(The) Arms Export Control Act (AECA) of 1976, 
see 22 U.S.C. 2778
ASME Y14.24, Types and Applications of Engineering 
Drawings , New York, 1999
ASME Y14.100, Engineering Drawing Practices , New 
York, 2004
ASQ, Statistics Division, Statistical Engineering, 
http://asq.org/statistics/quality-information/
statistical-engineering
2004
B
Ball, Robert E. The Fundamentals of Aircraft Combat 
Survivability Analysis and Design . 2nd Edition, 
AIAA Education Series, 2003
Bayer, T.J., M. Bennett, C. L. Delp, D. Dvorak, 
J. S. Jenkins, and S. Mandutianu. “Update: 
Concept of Operations for Integrated Model-
Centric Engineering at JPL,” paper #1122, IEEE 
Aerospace Conference 2011Blanchard, Benjamin S., System Engineering 
Blanchard, Benjamin S., and Wolter J. Fabrycky. 
Systems Engineering and Analysis , 5th Edition 
Prentice Hall International Series in Industrial 
& Systems Engineering; February 6, 2010
Brown, Barclay. “Model-based systems engineer -
ing: Revolution or Evolution,” IBM Software, 
Thought Leadership White Paper, IBM 
Rational , December 2011
2000.
Business Process Modeling Notation (BPMN)  http://
www.bpmn.org/
C
CCSDS 311.0-M-1, Reference Architecture for 
Space Data Systems, Recommended Practice 
(Magenta), Sept 2008. http://public.ccsds.org/
publications/MagentaBooks.aspx
CCSDS 901-0-G-1, Space Communications Cross 
Support Architecture Description Document , 
Informational Report (Green) Sept 2013. http://
public.ccsds.org/publications/GreenBooks.aspx
Chapanis, A. “The Error-Provocative Situation: 
A Central Measurement Problem in Human 272
Factors Engineering.” In The Measurement of 
Safety Performance . Edited by W. E. Tarrants. 
New York: Garland STPM Press, 1980
Chattopadhyay, Debarati, Adam M. Ross, and 
Donna H. Rhodes, “A Method for Tradespace 
Exploration of Systems of Systems,” presen -
tation in Track 34-SSEE-3: Space Economic 
Cost Modeling, AIAA Space 2009 , September 
15, 2009. © 2009 Massachusetts Institute

2000.
C
15, 2009. © 2009 Massachusetts Institute 
of Technology (MIT), SEARI: Systems 
Engineering Advancement Research Initiative, 
seari.mit.edu
Chung, Seung H., Todd J. Bayer, Bjorn Cole, Brian 
Cooke, Frank Dekens, Christopher Delp, 
Doris Lam. “Model-Based Systems Engineering 
Approach to Managing Mass Margin,” in 
Proceedings of the 5th International Workshop 
on Systems & Concurrent Engineering for Space 
Applications (SECESA),  Lisbon, Portugal, 
October, 2012
Clark, J.O. “System of Systems Engineering 
and Family of Systems Engineering From 
a Standards, V-Model, and Dual-V Model 
Perspective,” 3rd Annual IEEE International 
Systems Conference , Vancouver, Canada, March 
23–26, 2009
Clemen, R., and T. Reilly. Making Hard Decisions 
with DecisionTools Suite . Pacific Grove, CA: 
Duxbury Resource Center, 2002
CFR, Title 14 – Aeronautics and Space, Part 1214 
NASA Space Flight (14 CFR 1214)
CFR, Title 14 – Aeronautics and Space, Part 1216.3 
NASA Environmental Quality: Procedures for 
Implementing the National Environmental 
Policy Act (NEPA) (14 CFR 1216.3)CFR Title 22 – Foreign Relations, Parts 120-130 
Department of State: International Traffic in 
Arms Regulations (ITAR) (22 CFR 120-130). 
Implements 22 U.S.C. 2778 of the Arms Export 
Control Act (AECA) of 1976 and Executive 
Order 13637, “Administration of Reformed 
Export Controls,” March 8, 2013
CFR Title 37 – Patents, Trademarks, and 
Copyrights; Part 5 Secrecy of Certain 
Inventions and Licenses to Export and File 
Applications in Foreign Countries; Part 5.2 
Secrecy Order. (37 CFR 5.2)
CFR Title 40 – Protection of Environment, Part 
1508.27 Council on Environmental Quality: 
Terminology “significantly.” (40 CFR 1508.27)
CFR Title 48 – Federal Acquisition Regulation 
(FAR) System, Part 1214 NASA Acquisition 
Planning: Acquisition of Commercial Items: 
Space Flight. (48 CFR 1214)
(FAR) System, Part 46.103 Government 
Contract Quality Assurance: Contracting office 
responsibilities. (48 CFR 46.103)
(FAR) System, Part 46.4 Government Contract 
Quality Assurance (48 CFR 46.4)
(FAR) System, Part 46.407 Government 
Contract Quality Assurance: Nonconforming 
Supplies or Services (48 CFR 46.407)
COSPAR, Planetary Protection Policy . March 
24, 2005. http://w.astro.berkeley.edu/~kalas/
ethics/documents/environment/COSPAR%20
Planetary%20Protection%20Policy.pdf273
D
Deming, W. Edwards, see https://www.deming.org/
Dezfuli, H. “Role of System Safety in Risk-informed 
Decisionmaking.” In Proceedings, the NASA 
Risk Management Conference 2005 . Orlando, 
December 7, 2005
DOD Architecture Framework (DODAF)  Version 
2.02 Change 1, January 2015 http://dodcio.
defense.gov/Library/DoDArchitectureFramework.
aspx
DOD. Defense Acquisition Guidebook (DAG).  2014
DOD Defense Acquisition University (DAU). 
Systems Engineering Fundamentals Guide . Fort 
Belvoir, VA, 2001
DOD Defense Logistics Agency (DLA). Cataloging 
Handbook, H4/H8 Series . Washington, DC, 
February 2003
DOD Defense Technical Information Center 
(DTIC). Directory of Design Support Methods 
(DDSM) . 2007. http://www.dtic.mil/dtic/tr/fulltext/
u2/a437106.pdf
DOD MIL-HDBK-727 (Validation Notice 1). 
Military Handbook:  Design Guidance for 
Producibility , U.S. Army Research Laboratory, 
Weapons and Materials Research Directorate: 
Adelphi,MD, 1990
DOD. MIL-HDBK-965. Acquisition Practices 
for Parts Management . Washington, DC, 
September 26, 1996. Notice 1: October 2000
DOD. MIL-STD-881C. Work Breakdown Structure 
DC, October 3, 2011DOD. MIL-STD-1472G, DOD Design Criteria 
Standard: Human Engineering . Washington, 
DC, January 11, 2012
DOD. MIL-STD-1540D, Product Verification 
Requirements for Launch, Upper Stage, and Space 
Vehicles . January 15, 1999
DOD. MIL-STD-46855A, Human Engineering 
Requirements for Military Systems, Equipment, 
and Facilities . May 24, 2011. Replacement for 
DOD HDBK 763 and DOD MIL-HDBK-
46855A, which have been cancelled.
DOD Office of the Under Secretary of Defense, 
Acquisition, Technology, & Logistics. SD-10. 
Defense Standardization Program: Guide 
for Identification and Development of Metric 
Standards . Washington, DC, April, 2010
DOD Systems Management College. Systems 
Engineering Fundamentals . Defense Acquisition 
University Press: Fort Belvoir, VA 22060-
5565, 2001 http://ocw.mit.edu/courses/
aeronautics-and-astronautics/16-885j-air -
craft-systems-engineering-fall-2005/readings/sef -
guide_01_01.pdf
Duren, R. et al., “Systems Engineering for the 
Kepler Mission: A Search for Terrestrial 
Planets,” IEEE Aerospace Conference , 2006
E
Eggemeier, F. T., and G. F. Wilson. “Performance 
and Subjective Measures of Workload in 
Multitask Environments.” In Multiple-Task 
Performance . Edited by D. Damos. London: 
Taylor and Francis, 1991
Endsley, M. R., and M. D. Rogers. “Situation 
Awareness Information Requirements 274
Analysis for En Route Air Traffic Control.” In 
Proceedings of the Human Factors and Ergonomics 
Society 38th Annual Meeting . Santa Monica: 
Human Factors and Ergonomics Society, 1994
Eslinger, Suellen. Software Acquisition Best Practices 
for the Early Acquisition Phases . El Segundo, CA: 
The Aerospace Corporation, 2004
Estefan, Jeff, Survey of Model-Based Systems 
Engineering (MBSE) Methodologies , Rev B, 
Section 3.2. NASA Jet Propulsion Laboratory 
(JPL), June 10, 2008. The document was orig -
inally authored as an internal JPL report, and 
then modified for public release and submitted 
to INCOSE to support the INCOSE MBSE 
Initiative.
Executive Order (EO) 12114, Environmental Effects 
Abroad of Major Federal Actions . January 4, 
1979.
Executive Order (EO) 12770, Metric Usage in 
Federal Government Programs , July 25, 1991.
Executive Order (EO) 13637, Administration of 
Reformed Export Controls , March 8, 2013.
Extensible Markup Language (XML)  http://www.
w3.org/TR/REC-xml/
Extensible Markup Language (XML) Metadata 
Interchange (XMI)  http://www.omg.org/spec/XMI/
F
Federal Acquisition Regulation (FAR). See: Code of 
Federal Regulations (CFR), Title 48.
Federal Aviation Administration (FAA), 
HF-STD-001, Human Factors Design Standard (HFDS).  Washington, DC, May 2003. 
Updated: May 03, 2012. hf.tc.faa.gov/hfds
Federal Highway Administration, and CalTrans. 
Friedenthal, Sanford, Alan Moore, and Rick Steiner. 
A Practical Guide to SysML: Systems Modeling 
Language , Morgan Kaufmann Publishers, Inc., 
July 2008
Fuld, R. B. “The Fiction of Function Allocation.” 
Ergonomics in Design  (January 1993): 20–24
G
Garlan, D., W. Reinholtz, B. Schmerl, N. 
Sherman, T. Tseng. “Bridging the Gap 
between Systems Design and Space Systems 
Software,” Proceedings of the 29th IEEE/NASA 
Software Engineering Workshop , 6-7 April 2005, 
Greenbelt, MD, USA
Glass, J. T., V. Zaloom, and D. Gates. “A Micro-
Computer-Aided Link Analysis Tool.” 
Computers in Industry  16, (1991): 179–87
Gopher, D., and E. Donchin. “Workload: An 
Examination of the Concept.” In Handbook 
of Perception and Human Performance: Vol. II. 
Cognitive Processes and Performance . Edited by 
K. R. Boff, L. Kaufman, and J. P. Thomas. New 
York: John Wiley & Sons, 1986
“System Engineering and the Two Cultures 
University, March 28, 2007275
H
Hart, S. G., and C. D. Wickens. “Workload 
Assessment and Prediction.” In MANPRINT: 
An Approach to Systems Integration . Edited by H. 
R. Booher. New York: Van Nostrand Reinhold, 
1990
Hoerl, R.W. and R.S. Snee, Statistical Thinking – 
Improving Business Performance , John Wiley & 
Sons. 2012
Hoffmann, Hans-Peter, “Harmony-SE/SysML 
Deskbook: Model-Based Systems Engineering 
with Rhapsody,” Rev. 1.51, Telelogic/I-Logix 
white paper, Telelogic AB, May 24, 2006
Hofmann, Hubert F., Kathryn M. Dodson, Gowri 
S. Ramani, and Deborah K. Yedlin. Adapting 
CMMI® for Acquisition Organizations: A 
Preliminary Report , CMU/SEI-2006-SR-005. 
Pittsburgh: Software Engineering Institute, 
Carnegie Mellon University, 2006, pp. 338–40
Huey, B. M., and C. D. Wickens, eds. Workload 
Transition . Washington, DC: National Academy 
Press, 1993
I
IEEE STD 610.12-1990. IEEE Standard Glossary 
of Software Engineering Terminology . 1999, 
superceded by ISO/IEC/IEEE 24765:2010 , 
Systems and Software Engineering – Vocabulary . 
Washington, DC, 2010
IEEE STD 828. IEEE Standard for Software 
Configuration Management Plans . Washington, 
DC, 1998
IEEE STD 1076-2008 IEEE Standard VHDL 
Language Reference Manual , 03 February 2009IEEE STD 1220-2005. IEEE Standard for 
Engineering Process , Washington, DC, 2005

I
DC, 1998
IEEE Standard12207.1, EIA Guide for Information 
Technology Software Life Cycle Processes—Life 
Cycle Data , Washington, DC, 1997
INCOSE. Systems Engineering Handbook , Version 
3.2.2. Seattle, 2011
and Activities , Version 4, Edited by Walden, 
INCOSE-TP-2003-020-01, Technical Measurement , 
Version 1.0, 27 December 2005. Prepared by 
Garry J. Roedler (Lockheed Martin) and Cheryl 
Jones (U.S. Army).
INCOSE-TP-2004-004-02, Systems Engineering 
Vision 2020 , Version 2.03, September 2007, 
http://www.incose.org/ProductsPubs/pdf/
SEVision2020_20071003_v2_03.pdf
INCOSE-TP-2005-001-03, Systems Engineering 
Leading Indicators Guide , Version 2.0, January 
29, 2010; available at http://seari.mit.edu/docu -
ments/SELI-Guide-Rev2.pdf . Edited by Garry J. 
Roedler and Howard Schimmoller (Lockheed 
Martin), Cheryl Jones (U.S. Army), and 
Donna H. Rhodes (Massachusetts Institute of 
Technology)
ISO 9000:2015, Quality management systems – 
Fundamentals and vocabulary . Geneva: 
International Organization for Standardization, 
2015276
ISO 9001:2015 Quality Management Systems 
(QMS).  Geneva: International Organization for 
Standardization, September 2015
ISO 9100/AS9100, Quality Systems Aerospace—
Model for Quality Assurance in Design, 
Development, Production, Installation, and 
Servicing . Geneva: International Organization 
for Standardization, 1999
ISO 10007: 1995(E). Quality Management—
Guidelines for Configuration Management , 
Standardization, 1995
ISO 10303-AP233, Application Protocol (AP) for 
Systems Engineering Data Exchange (AP-233)  
Working Draft 2 published July 2006
ISO/TS 10303-433:2011 Industrial automation 
systems and integration – Product data representa -
tion and exchange – Part 433: Application mod -
ule: AP233 systems engineering . ISO: Geneva, 
2011
ISO/IEC 10746-1 to 10746-4, ITU-T Specifications 
X.901 to x.904, Reference Model of Open 
distributed Processing (RM-ODP),  Geneva: 
1998. http:// www.rm-odp.net
ISO 13374-1, Condition monitoring and diagnostics of 
machines—Data processing, communication and 
presentation – Part 1: General guidelines . Geneva: 
2002
ISO/IEC 15288:2002. Systems Engineering—System 
Life Cycle Processes . Geneva: International 
Organization for Standardization, 2002ISO/TR 15846. Information Technology—Software 
Life Cycle Processes Configuration Management , 
Standardization, 1998
ISO/IEC TR 19760:2003. Systems Engineering—A 
Guide for the Application of ISO/IEC 15288. 
Standardization, 2003
ISO/IEC/IEEE 24765:2010, Systems and 
Software Engineering – Vocabulary. Geneva: 
2010
ISO/IEC/IEEE 42010:2011. Systems and Software 
Engineering—Architecture Description. 
Standardization, 2011 http://www.iso-architec -
ture.org/ieee-1471/index.html
(The) Invention Secrecy Act of 1951, see 35 U.S.C. 
of Patent
J
Jennions, Ian K. editor. Integrated Vehicle Health 
Management (IVHM): Perspectives on an 
Emerging Field . SAE International, Warrendale 
PA (IVHM Book) September 27, 2011
Management (IVHM): Business Case Theory and 277
Practice . SAE International, Warrendale PA 
(IVHM Book) November 12, 2012
Management (IVHM): The Technology . SAE 
International, Warrendale PA (IVHM Book) 
September 5, 2013
Johnson, Stephen B. et al., editors. System Health 
Management with Aerospace Applications . John 
Wiley & Sons, Ltd, West Sussex, UK, 2011
Jones, E. R., R. T. Hennessy, and S. Deutsch, 
eds. Human Factors Aspects of Simulation . 
Washington, DC: National Academy Press, 
1985
K
Kaplan, S., and B. John Garrick. “On the 
Quantitative Definition of Risk.” Risk Analysis  
1(1). 1981
Karpati, G., Martin, J., Steiner, M., Reinhardt, 
K., “The Integrated Mission Design Center 
(IMDC) at NASA Goddard Space Flight 
Center,” IEEE Aerospace Conference 2003 
Proceedings , Volume 8, Page(s): 8_3657–8_3667, 
2003
Keeney, Ralph L. Value-Focused Thinking: A Path 
to Creative Decisionmaking . Cambridge, MA: 
Harvard University Press, 1992
Keeney, Ralph L., and Timothy L. McDaniels. “A 
Framework to Guide Thinking and Analysis 
Regarding Climate Change Policies.” Risk 
Analysis  21(6): 989–1000. 2001
Keeney, Ralph L., and Howard Raiffa. Decisions 
with Multiple Objectives: Preferences and Value Tradeoffs . Cambridge, UK: Cambridge 
University Press, 1993
Kirwin, B., and L. K. Ainsworth. A Guide to Task 
Analysis . London: Taylor and Francis, 1992
Kluger, Jeffrey with Dan Cray, “Management 
Tips from the Real Rocket Scientists,” Time 
Magazine , November 2005
Knowledge Based Systems, Inc. (KBSI), Integration 
Definition for functional modeling (IDEF0) ISF0 
Function Modeling Method , found at http://www.
idef.com/idef0.htm
Kruchten, Philippe B. The Rational Unified Process: 
An Introduction , Third Edition, Addison-Wesley 
Professional: Reading, MA, 2003
Kruchten, Philippe B. “A 4+1 view model of soft -
ware architecture,” IEEE Software Magazine  
12(6) (November 1995), 42–50
Kurke, M. I. “Operational Sequence Diagrams in 
System Design.” Human Factors  3: 66–73. 1961
L
Larson, Wiley J.et al.. Applied Space Systems 
Engineering: A Practical Approach to Achieving 
Technical Baselines . 2nd Edition, Boston, 
MA: McGraw-Hill Learning Solutions, CEI 
Publications, 2009
Long, James E., Relationships Between Common 
Graphical Representations in Systems Engineering . 
Long, James E., “Systems Engineering (SE) 101,” 
CORE®: Product & Process Engineering Solutions , 
Vitech training materials. Vienna, VA: Vitech 
Corporation, 2000278
M
Maier, M.W. “Architecting Principles for Systems-of-
Systems,” Systems Engineering  1(1998), 267-284, 
John Wiley & Sons, Inc.
Maier, M.W., D. Emery, and R. Hillard, “ANSI/
IEEE 1471 and Systems Engineering,” 
Systems Engineering  7 (2004), 257–270, Wiley 
InterScience, http:// www.interscience.wiley.com
Maier, M.W. “System and Software Architecture 
Reconciliation,” Systems Engineering  9 (2006), 
146–159, Wiley InterScience, http:// www.inter -
science.wiley.com
Maier, M.W., and E. Rechtin, The Art of Systems 
Architecting , 3rd Edition, CRC Press, Boca 
Raton, FL, 2009
Martin, James N., Processes for Engineering a System: 
An Overview of the ANSI/GEIA EIA-632 
Standard and Its Heritage . New York: Wiley & 
Sons, 2000
Martin, James N., Systems Engineering Guidebook: A 
Process for Developing Systems and Products . Boca 
Raton: CRC Press, 1996.
Mathworks: Matlab  http://www.mathworks.com/
McGuire, M., Oleson, S., Babula, M., and Sarver-
Verhey, T., “Concurrent Mission and Systems 
Design at NASA Glenn Research Center: The 
origins of the COMPASS Team,” AIAA Space 
2011 Proceedings , September 27-29, 2011, Long 
Beach, CA
Meister, David, Behavioral Analysis and Measurement 
Methods . New York: John Wiley & Sons, 1985Meister, David, Human Factors: Theory and Practice . 
New York: John Wiley & Sons, 1971
(The) Metric Conversion Act of 1975 (Public Law 
94-168) amended by the Omnibus Trade and 
Competitiveness Act of 1988 (Public Law 100-
418), the Savings in Construction Act of 1996 
(Public Law 104-289), and the Department of 
Energy High-End Computing Revitalization 
Act of 2004 (Public Law 108-423). See 15 
U.S.C. §205a et seq.
Miao, Y., and J. M. Haake. “Supporting Concurrent 
Design by Integrating Information Sharing and 
Activity Synchronization.” In Proceedings of the 
5th ISPE International Conference on Concurrent 
Engineering Research and Applications (CE98) . 
Tokyo, 1998, pp. 165–74
The Mitre Corporation, Common Risks and Risk 
Mitigation Actions for a COTS-based System . 
McLean, VA. http://www2.mitre.org/…/files/
CommonRisksCOTS.doc  (no date)
MODAF http://www.modaf.com/
Moeller, Robert C., Chester Borden, Thomas 
Spilker, William Smythe, Robert Lock , 
“Space Missions Trade Space Generation 
and Assessment using the JPL Rapid Mission 
Architecture (RMA) Team Approach,” IEEE 
Aerospace Conference , Big Sky, Montana, March 
2011
Morgan, M. Granger, and M. Henrion, Uncertainty: 
A Guide to Dealing with Uncertainty in 
Quantitative Risk and Policy Analysis . 
Cambridge, UK: Cambridge University Press, 
1990279

2011
1990279
M. Moshir, et al., “Systems engineering and appli -
cation of system performance modeling in SIM 
Lite mission,” Proceedings. SPIE  7734, 2010
Mulqueen, J.; R. Hopkins; D. Jones, “The MSFC 
Collaborative Engineering Process for 
Preliminary Design and Concept Definition 
Studies.” 2012 http://ntrs.nasa.gov/archive/nasa/
casi.ntrs.nasa.gov/20120001572.pdf
NASA Publications
Management System Policy
Information
Reports
Action Team (NIAT) report, “Enhancing 
Mission Success—A Framework for the Future,” 
December 21, 2000. Authors: McBrayer, Robert 
O and Thomas, Dale, NASA Marshall Space 
Flight Center, Huntsville, AL United States
html
Report , Sept. 13, 2004. http://www.nasa.gov/pdf/
Excellence: An Assessment of the NASA Agency-
wide Applicability of the Columbia Accident Investigation Board Report , January 30, 2004. 
Center, and team
NASA JPL D-71990, Europa Study 2012 Full Report . 
May 1 2012, publicly available here: http://
solarsystem.nasa.gov/europa/2012study.cfm
NASA Office of Inspector General. Final 
Memorandum on NASA’s Acquisition Approach 
Regarding Requirements for Certain Software 
Engineering Tools to Support NASA Programs , 
Assignment No. S06012. Washington, DC, 
2006
NASA Office of Inspector General. Performance-
Based Contracting https://oig.nasa.gov/august/
report/FY06/s06012
Specialty Web Sites
under Tools and Methods at https://nen.nasa.
gov/web/se/tools/  and then NASA Tools & 
Methods
Community of Practice, https://nen.nasa.gov/
web/pm/evm
NASA EVM website http://evm.nasa.gov/index.html280
NASA Procurement Library found at http://www.
hq.nasa.gov/office/procurement/
Conference Publications
NASA 2011 Statistical Engineering Symposium, 
Proceedings . http://engineering.larc.nasa.gov/2011_
NASA_Statistical_Engineering_Symposium.html
Aerospace Conference, 2007 IEEE  Big Sky, MT 3–10 
March 2007. NASA/Aerospace Corp. paper: 
“Using Historical NASA Cost and Schedule 
Growth to Set Future Program and Project 
Reserve Guidelines,” by Emmons, D. L., R.E. 
Bitten, and C.W. Freaner. IEEE Conference 
Publication pages: 1–16, 2008. Also presented 
at the NASA Cost Symposium, Denver CO, 
July 17–19, 2007
NASA Cost Symposium 2014 , NASA “Mass Growth 
Analysis: Spacecraft & Subsystems.” LaRC, 
August 14th, 2014. Presenter: Vincent Larouche 
– Tecolote Research, also James K. Johnson, 
NASA HQ Study Point of Contact
Planetary Science Subcommittee, NASA Advisory 
Council, 23 June, 2008, NASA GSFC. NASA/
Aerospace Corp. presentation; “An Assessment 
of the Inherent Optimism in Early Conceptual 
Designs and its Effect on Cost and Schedule 
Growth,” by Freaner, Claude, Bob Bitten, Dave 
Bearden, and Debra Emmons
Technical Documents
NASA Office of Chief Information Officer (OCIO). 
Information Technology Systems Engineering 
Handbook  Version 2.0
NASA Science Mission Directorate, Risk 
Communication Plan for Planetary and Deep 
Space Missions , 1999NASA PD-EC-1243, Preferred Reliability Practices 
for Fault Protection , October 1995
NASA-CR-192656, Contractor Report:  Research 
and technology goals and objectives for Integrated 
Vehicle Health Management (IVHM).  October 
10, 1992
NASA Jet Propulsion Laboratory (JPL), JPL-
D-17868 (REV.1), JPL Guideline: Design, 
Verification/Validation and Operations Principles 
for Flight Systems . February 16, 2001
65995), Commercial Human Systems Integration 
Processes (CHSIP) , May 2011
NASA/TP-2014-218556, Technical Publication: 
Human Integration Design Processes (HIDP).  
NASA ISS Program, Lyndon B. Johnson Space 
Center, Houston TX, September 2014. http://
ston.jsc.nasa.gov/collections/TRS/_techrep/
TP-2014-218556.pdf
Management Plan , May 9, 2007
NASA Langley Research Center (LARC) Guidance 
Based Contracting . 2013 sites-e.larc.nasa.gov/
sweng/files/2013/05/Guidance_on_Metrics_for_
PBC_R1V01.doc
2013 http://sw-eng.larc.nasa.gov/files/2013/05/
pdf281
NASA/TM-2008-215126/Volume II (NESC-
RP-06-108/05-173-E/Part 2), Technical 
Memorandum: Design Development Test and 
Evaluation (DDT&E) Considerations for Safe and 
Reliable Human-Rated Spacecraft Systems . April 
2008.Volume II: Technical Consultation Report . 
James Miller, Jay Leggett, and Julie Kramer-
White, NASA Langley Research Center, 
Hampton VA, June 14, 2007
NASA Reference Publication 1370. Training 
Control.  Vincent R. Lalli, Robert E. Kastner, 
and Henry N. Hartt. NASA Lewis Research 
Center, Cleveland OH, January 1997
NASA. Systems Engineering Leading Indicators 
Guide , http://seari.mit.edu/
Februar y 2015
NASA  Financial Management Requirements (FMR)  
Volume 4
Special Publications
NASA/SP-2010-576 NASA Risk-Informed Decision 
Making Handbook
Handbook
NASA/SP-2010-3404, NASA Work Breakdown 
NASA/SP-2010-3406, Integrated Baseline Review 
(IBR) HandbookNA SA /SP-2010 -3407, Human Integration Design 
Handbook (HIDH)
Handbook
NASA/SP-2013-3704, Earned Value Management 
(EVM) System Description
NASA /SP-2015-3709, Human Systems Integration 
Practitioners Guide
Handbooks and Standards
Handbook , Draft 2, April 2012
Handbook , February 28, 2013
NASA Safety Standard (NSS) 1740.14, Guidelines 
and Assessment Procedures for Limiting Orbital 
Debris . Washington, DC, 1995 http://www.
hq.nasa.gov/office/codeq/doctree/174014.htm  
NASA-STD 8719.14 should be used in place 
of NSS 1740.14 to implement NPR 8715.6. See 
NPR 8715.6  for restrictions on the use of NSS 
1740.14.
NASA GSFC-STD-1000, Rules for the Design, 
Development, Verification, and Operation of 
Flight Systems . NASA Goddard Space Flight 
Center, February 8, 2013282
NASA-STD-3001, Space Flight Human System 
Standard . Volume 1: Crew Health . Rev. A, July 
30, 2014
Standard . Volume 2: Human Factors, 
Habitability, and Environmental Health . Rev. A, 
February 10, 2015
Projects . Goddard Space Flight Center, April 
2005
NASA KSC-NE-9439 Kennedy Space Center Design 
Engineering Handbook, Best Practices for Design 
and Development of Ground Systems . Kennedy 
Space Center, November 20 2009
2013
C. Washington, DC, May 7, 2013
Debris . Rev A with Change 1. December 8, 2011
DC, December 1, 1998
Policy Directives
Controlled InformationNPD 2820.1, NASA Software Policy
Projects
NPD 8010.2, Use of the SI (Metric) System of 
Measurement in NASA Programs

2013
Projects
NPD 8020.7, Biological Contamination Control for 
Outbound and Inbound Planetary Spacecraft
Policy
Procedural Requirements
NASA Research and Technology (R&T)
NPR 1441.1, NASA Records Retention Schedules
NPR 1600.1, NASA Security Program Procedural 
LPR 5000.2, Procurement Initiator’s Guide. NASA 
Langley Research Center (LARC)
JPR 7120.3, Project Management: Systems 
Engineering & Project Control Processes and 
Requirements. NASA Lyndon B. Johnson Space 
Center (JSC)283
NPR 7120.5, NASA Space Flight Program 
and Project Management Processes and 
NPR 7120.11, NASA Health and Medical Technical 
Authority (HMTA) Implementation
NPR 8000.4, Risk Management Procedural 
NPI 8020.7, NASA Policy on Planetary Protection 
Requirements for Human Extraterrestrial 
Missions
NPR 8020.12, Planetary Protection Provisions for 
Robotic Extraterrestrial Missions
APR 8070.2, EMI/EMC Class D Design and 
Environmental Test Requirements. NASA Ames 
Research Center (ARC)
NPR 8580.1, Implementing the National 
Environmental Policy Act and Executive Order 
12114NPR 8705.2, Human-Rating Requirements for 
NPR 8705.3, Probabilistic Risk Assessment 
NPR 8705.5, Probabilistic Risk Assessment (PRA) 
Procedures for NASA Programs and Projects
NPR 8710.1, Emergency Preparedness Program
NPR 8715.2, NASA Emergency Preparedness Plan 
Limiting Orbital Debris
NPR 8900.1, NASA Health and Medical 
Requirements for Human Space Exploration
Work Instructions
MSFC NASA MWI 8060.1, Off-the-Shelf Hard -
ware Utilization in Flight Hardware Develop -
ment. NASA Marshall Space Flight Center.
JSC Work Instruction EA-WI-016, Off-the-Shelf 
Hardware Utilization in Flight Hardware 
Development. NASA Lyndon B. Johnson Space 
Center.284
Acquisition Documents
NASA. The SEB Source Evaluation Process . 
Washington, DC, 2001
NASA. Solicitation to Contract Award . Washington, 
DC, NASA Procurement Library, 2007
NASA. Statement of Work Checklist . Washington, 
DC. See: Appendix P  in this handbook.
N
National Research Council (NRC) of the National 
Academy of Sciences (NAS), The Planetary 
Decadal Survey 2013–2022, Vision and Voyagers 
for Planetary Science in the Decade 2013 –2022 , 
The National Academies Press: Washington, 
D.C., 2011. http://www.nap.edu
NIST Special Publication 330: The International 
System of Units (SI)  Barry N. Taylor and Ambler 
Thompson, Editors, March 2008. The United 
States version of the English text of the eighth 
edition (2006) of the International Bureau of 
Weights and Measures publication Le Système 
International d’ Unités (SI)
NIST Special Publication 811: NIST Guide for the 
Use of the International System of Units (SI)  A. 
Thompson and B. N. Taylor, Editors. Created 
July 2, 2009; Last updated January 28, 2016
NIST, Federal Information Processing Standard 
Publication (FIPS PUB) 199, Standards for 
Security Categorization of Federal Information 
and Information Systems,  February 2004O
Oberto, R.E., Nilsen, E., Cohen, R., Wheeler, R., 
DeFlorio, P., and Borden, C., “The NASA 
Exploration Design Team; Blueprint for a 
New Design Paradigm”, 2005 IEEE Aerospace 
Conference , Big Sky, Montana, March 2005
Object Constraint Language (OCL)  http://www.omg.
org/spec/OCL/
A-94, Guidelines and Discount Rates for Benefit-
Cost Analysis of Federal Programs , October 29, 
1992
Oliver, D., T. Kelliher, and J. Keegan, Engineering 
Complex Systems with Models and Objects , New 
York, NY, USA: McGraw-Hill 1997
OOSEM Working Group, Object-Oriented Systems 
Engineering Method (OOSEM) Tutorial , Version 
03.00, Lockheed Martin Corporation and 
INCOSE, October 2008
OWL, Web Ontology Language (OWL)  http://www.
w3.org/2001/sw/wiki/OWL
P
Paredis, C., Y. Bernard, R. Burkhart, H.P. Koning, 
S. Friedenthal, P. Fritzon, N.F. Rouquette, 
W. Schamai. “Systems Modeling Language 
(SysML)-Modelica Transformation.” INCOSE 
2010
Pennell, J. and Winner, R., “Concurrent 
Engineering: Practices and Prospects,” Global 
Telecommunications Conference, GLOBECOM 
‘89, 1989
Presidential Directive/National Security Council 
Memorandum No. 25 (PD/NSC-25), “Scientific 285
or Technological Experiments with Possible 
Large-Scale Adverse Environmental Effects 
and Launch of Nuclear Systems into Space,” as 
amended May 8, 1996
Presidential Policy Directive PPD-4 (2010), National 
Space Policy
Price, H. E. “The Allocation of Functions in 
Systems.” Human Factors  27: 33–45. 1985
The Project Management Institute® (PMI). Practice 
Standards for Work Breakdown Structures . 
Newtown Square, PA, 2001
Q
Query View Transformation (QVT)  http://www.omg.
org/spec/QVT/1.0/
R
Rasmussen, Robert. “Session 1: Overview of 
State Analysis,” (internal document), State 
Analysis Lite Course , Jet Propulsion Laboratory, 
California Institute of Technology, Pasadena, 
CA, 2005
R. Rasmussen, B. Muirhead, Abridged Edition:  
A Case for Model-Based Architecting in NASA , 
California Institute of Technology, August 2012
Raton: CRC Press, 2000
S
New York: McGraw-Hill, 1980SAE Standard AS5506B, Architecture Analysis & 
Design Language (AADL) , SAE International, 
September 10, 2012
SAE International and the European Association of 
Aerospace Industries (EAAI) AS9100C, Quality 
Management Systems (QMS): Requirements for 
Aviation, Space, and Defense Organizations 
Revision C, January 15, 2009
SAE International/Electronic Industries Alliance 
(EIA) 649B-2011, Configuration Management 
Standard (Aerospace Sector) , April 1, 2011
of Systems Engineering and Management , New 
Shafer, J. B. “Practical Workload Assessment in the 
Development Process.” In Proceedings of the 
Human Factors Society 31st Annual Meeting , 
Santa Monica: Human Factors Society, 1987
Shames, P., and J. Skipper. “Toward a Framework 
for Modeling Space Systems Architectures,” 
SpaceOps 2006 Conference , AIAA 2006-5581, 
2006
Shaprio, J., “George H. Heilmeier,” IEEE Spectrum , 
31(6), 1994, pg. 56–59 http://ieeexplore.ieee.org/
iel3/6/7047/00284787.pdf?arnumber=284787
Software Engineering Institute (SEI). A Framework 
for Software Product Line Practice , Version 5.0. 
Carnegie Mellon University, http:// www.sei.cmu.
edu/productlines/frame_report/arch_def.htm
Stamelatos, M., H. Dezfuli, and G. Apostolakis. 
“A Proposed Risk-Informed Decision making 
Framework for NASA.” In Proceedings of the 8th 
International Conference on Probabilistic Safety 286
Assessment and Management . New Orleans, LA, 
May 14–18, 2006
Stern, Paul C., and Harvey V. Fineberg, eds. 
Understanding Risk: Informing Decisions in a 
Democratic Society . Washington, DC: National 
Academies Press, 1996
Systems Modeling Language (SysML)  http://www.
omgsysml.org/
T
Taylor, Barry. Guide for the Use of the International 
System of Units (SI),  Special Publication 811. 
Gaithersburg, MD: NIST, Physics Laboratory, 
2007
U
Unified Modeling Language (UML)  http://www.uml.
org/
UPDM: Unified Profile for the (US) Department 
of Defense Architecture Framework (DoDAF) 
and the (UK) Ministry Of Defense Architecture 
Framework (MODAF)  http://www.omg.org/spec/
UPDM/
U.S. Air Force. SMC Systems Engineering Primer 
and Handbook , 3rd ed. Los Angeles: Space and 
Missile Systems Center, 2005
U. S. Chemical Safety Board (CSB) case study 
U.S. Navy. Naval Air Systems Command, Systems 
Engineering Guide : 2003 (based on require -
ments of ANSI/EIA 632:1998). Patuxent River,

T
2007
U
org/
UPDM/
ments of ANSI/EIA 632:1998). Patuxent River, 
MD, 2003
U.S. Nuclear Regulatory Commission. SECY-
98-144, White Paper on Risk-Informed and Performance-Based Regulation , Washington, DC, 
1998
U.S. Nuclear Regulatory Commission. NUREG-
0700, Human-System Interface Design Review 
Guidelines , Rev.2. Washington, DC, Office of 
Nuclear Regulatory Research, 2002
United Nations, Office for Outer Space Affairs. 
Treaty of Principles Governing the Activities of 
States in the Exploration and Use of Outer Space, 
Including the Moon and Other Celestial Bodies . 
Known as the “Outer Space Treaty of 1967”
W
Wall, S., “Use of Concurrent Engineering in Space 
Mission Design,” Proceedings of EuSEC 2000 , 
Munich, Germany, September 2000
Warfield, K., “Addressing Concept Maturity in the 
Early Formulation of Unmanned Spacecraft,” 
Proceedings of the 4th International Workshop 
on System and Concurrent Engineering for Space 
Applications , October 13–15, 2010, Lausanne, 
Switzerland
Web Ontology Language (OWL) http://www.
Wessen, Randii R., Chester Borden, John Ziemer, 
and Johnny Kwok. “Space Mission Concept 
Development Using Concept Maturity Levels,” 
Conference paper presented at the American 
Institute of Aeronautics and Astronautics 
(AIAA) Space 2013 Conference and Exposition; 
September 10–12, 2013; San Diego, CA. 
Published in the AIAA Space 2013 Proceedings
Winner, R., Pennell, J., Bertrand, H., and 
Slusarczuk, M., The Role Of Concurrent 
Engineering In Weapons System Acquisition , 287
Institute of Defense Analyses (IDA) Report 
R-338, Dec 1988
Wolfram, Mathematica http://www.wolfram.com/
mathematica/
X
XMI: Extensible Markup Language (XML) 
Metadata Interchange (XMI) http://www.omg.
org/spec/XMI/XML: Extensible Markup Language (XML) http://
www.w3.org/TR/REC-xml/
Z
Ziemer, J., Ervin, J., Lang, J., “Exploring Mission 
Concepts with the JPL Innovation Foundry 
A-Team,” AIAA Space 2013 Proceedings , 
September 10–12, 2013, San Diego, CA