NASA Systems Engineering Handbook SP-610S June 1995 Contents Foreword ................................ ................................ ................................ ............................ ix Foreword to the September 1992 Draft ................................ ................................ .. x Preface ................................ ................................ ................................ ............................... xi Acknowledgements ................................ ................................ ................................ .......... xii Introduction ................................ ................................ ................................ ....................... 1 Purpose ................................ ................................ ................................ ................... 1 Scope and Depth ................................ ................................ ................................ .... 1 Fundamentals of System Engineering ................................ ................................ ........... 3 Systems, Supersystems, and Subsystems ................................ ............................ 3 Definition of Systems Engineering ................................ ................................ .......... 4 Objective of Systems Engineering ................................ ................................ .......... 4 Disciplines Related to Systems Engineering ................................ .......................... 6 The Doctrine of Successive Rinfinement ................................ ................................ 7 The Project Cycle for Major NASA Systems ................................ ................................ 13 Pre-Phase A - Advanced Studies ................................ ................................ ........... 13 Phase A - Preliminary Analysis ................................ ................................ ............... 14 Phase B - Definition ................................ ................................ ................................ 17 Phase C - Design ................................ ................................ ................................ .... 18 Phase D - Development ................................ ................................ .......................... 19 Phase E - Operations ................................ ................................ .............................. 19 Role of Systems Engineering in the Project Life Cycle ................................ .......... 20 The “Vee” Chart ................................ ................................ ........................... 20 The NASA Program/Project Life Cycle Process Flow................................. 22 Funding: The Budget Cycle ................................ ................................ .................... 25 Management Issues in Systems Engineering ................................ ............................... 27 Harmony of Goals, Work Products, and Organizations ................................ ......... 27 Managing the Systems Engineering Process: The Systems Engineering Management Plan ................................ ................................ ................................ ... 28 Role of the SEMP ................................ ................................ ........................ 28 Contents of the SEMP ................................ ................................ ................. 28 Development of the SEMP ................................ ................................ .......... 29 Managing the Systems Engineering Process: Summary .......................... 30 The Work Breakdown Structure ................................ ................................ .............. 30 Role of the WBS ................................ ................................ .......................... 31 Techniques for Developing the WBS ................................ .......................... 31 Common Errors in Developing a WBS ................................ ....................... 32 Scheduling ................................ ................................ ................................ ............... 33 Role of Scheduling ................................ ................................ ....................... 33 Network Schedule Data and Graphical Formats ................................ ........ 33 Establishing a Network Schedule ................................ ................................ 34 Reporting Techniques ................................ ................................ ................. 35 Resource Leveling ................................ ................................ ....................... 35 Contents Budgeting and Resource Planning ................................ ................................ ..................... 35 Risk Management ................................ ................................ ................................ ............... 37 Types of Risks ................................ ................................ ................................ ........ 39 Risk Identification and Characterization Techniques ................................ ............. 40 Risk Analysis Techniques ................................ ................................ ...................... 41 Risk Mitigation and Tracking Techniques ................................ .............................. 42 Risk Management: Summary ................................ ................................ ............... 44 Configuration Management ................................ ................................ ................................ 44 Baseline Evolution ................................ ................................ ................................ .. 45 Techniques of Configuration Management ................................ ............................ 45 Data Management ................................ ................................ ................................ .. 48 Reviews, Audits, and Control Gates ................................ ................................ ................... 48 Purpose and Definitions ................................ ................................ ......................... 48 General Principles for Reviews ................................ ................................ .............. 49 Major Control Gates ................................ ................................ ............................... 50 Interim Review ................................ ................................ ................................ ....... 55 Status Reporting and Assessment ................................ ................................ ..................... 58 Cost and Schedule Control Measures ................................ ................................ ... 59 Technical Performance Measures ................................ ................................ ......... 61 Systems Engineering Process Metrics ................................ ................................ .. 64 Systems Analysis and Modeling Issues ................................ ................................ ..................... 67 The Trade Study Process ................................ ................................ ................................ ... 67 Controlling the Trade Study Process ................................ ................................ ..... 70 Using Models ................................ ................................ ................................ .......... 71 Selecting the Selection Rule ................................ ................................ .................. 73 Trade Study Process: Summary ................................ ................................ ........... 77 Cost Definition and Modeling ................................ ................................ .............................. 77 Life-Cycle Cost and Other Cost Measures ................................ ............................ 77 Controlling Life-Cycle Costs ................................ ................................ ................... 79 Cost Estimating ................................ ................................ ................................ ...... 80 Effectiveness Definition and Modeling ................................ ................................ ............... 83 Strategies for Measuring System Effectiveness ................................ .................... 83 NASA System Effectiveness Measures ................................ ................................ 84 Availability and Logistics Supportability Modeling ................................ ................. 85 Probabilistic Treatment of Cost and Effectiveness ................................ ............................ 87 Sources of Uncertainty in Models ................................ ................................ .......... 88 Modeling Techniques for Handling Uncertainty ................................ ..................... 88 Integrating Engineering Specialties Into the Systems Engineering Process ........................ 91 Role of the Engineering Specialties ................................ ................................ ................... 91 Reliability ................................ ................................ ................................ ............................. 91 Role of the Reliability ................................ ................................ ............................. 92 Designing Reliable Space-Based Systems ...............................