Https nen nasa gov web se doc repository

1. What output comes from the systems engineering process?

2. Why does Mr. Ryen consider stakeholder involvement to be key?

3. What is meant by a “Tops Down/Bottoms up” process?

4. What do ConOps contain?

5. What benefit do “use cases” provide?

**The sources to be used are uploaded. Please do not use any other sources.

· Systems Engineering Process Overview, Ed Ryen (PE), North Dakota Dept of Transportation, March 2008 (Page 1- 9)Only

· NASA Systems Engineering Handbook, NASA SP-2016-6105 REV 2 (Page 43-53)Only

· Systems Engineering Fundamentals, US DoD Systems Management College, January 2001, Defense Acquisition University Press (chapter3)Only

National Aeronautics and Space Administration

NASA SYSTEMS ENGINEERING

HANDBOOK

design

test

integrate

fly

www.nasa.gov

NASA 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.gov

http://steven.r.hirshorn@nasa.gov
iiiNASA SYSTEMS ENGINEERING HANDBOOK

Table 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 . . . . . . . 31

3.10 Funding: The Budget Cycle . . . . . . . 33 3.11 Tailoring and Customization of

NPR 7123 .1 Requirements . . . . . . . 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 . . . . . . . . . . . 88

ivNASA SYSTEMS ENGINEERING HANDBOOK

Table of Contents

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 112

6.0 Crosscutting Technical Management 113

6.1 Technical Planning . . . . . . . . . . 113 6.1.1 Process Description 114

6.1.2 Technical Planning Guidance 130

6.2 Requirements Management . . . . . 130 6.2.1 Process Description 131

6.2.2 Requirements Management Guidance 135

6.3 Interface Management . . . . . . . . 135 6.3.1 Process Description 136

6.3.2 Interface Management Guidance 138

6.4 Technical Risk Management . . . . . 138 6.4.1 Risk Management Process

Description 141

6.4.2 Risk Management Process Guidance 143

6.5 Configuration Management . . . . . . 143 6.5.1 Process Description 144

6.5.2 CM Guidance 150

6.6 Technical Data Management . . . . . 151 6.6.1 Process Description 151

6.6.2 Technical Data Management Guidance 155

6.7 Technical Assessment . . . . . . . . 155 6.7.1 Process Description 157

6.7.2 Technical Assessment Guidance 160

6.8 Decision Analysis . . . . . . . . . . . 160 6.8.1 Process Description 164

6.8.2 Decision Analysis Guidance 170

Appendix 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 270

vNASA SYSTEMS ENGINEERING HANDBOOK

Table 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 . . . 79

Figure 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 . . . . . . . 213

viNASA SYSTEMS ENGINEERING HANDBOOK

Table 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 . . . . 118

Table 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 . . . . . 250

viiNASA SYSTEMS ENGINEERING HANDBOOK

Table of Boxes

The Systems Engineer’s Dilemma . . . . . . . . . . 12

Space Flight Program Formulation . . . . . . . . . . 20

Space Flight Program Implementation . . . . . . . . 21

Space Flight Pre-Phase 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 . . . . . . . . . . . . . . . 78

Differences 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 . . . . . . . . . . . . . . . . . 250

viiiNASA SYSTEMS ENGINEERING HANDBOOK

Preface

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.

ixNASA SYSTEMS ENGINEERING HANDBOOK

Acknowledgments

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 Center

Grantier, 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

Killebrew, Jana, NASA/Ames Research Center

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 Center

xNASA SYSTEMS ENGINEERING HANDBOOK

Acknowledgments

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 Laboratory

Trase, 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 Center

1NASA SYSTEMS ENGINEERING HANDBOOK

1.0 Introduction

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 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.

https://nen.nasa.gov/web/se
2

1.0 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.

https://nen.nasa.gov/web/se/doc-repository
3NASA SYSTEMS ENGINEERING HANDBOOK

2.0 Fundamentals 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 . Griffin, NASA Administrator .

4

2.0 Fundamentals of Systems Engineering