Table of Contents Acknowledgements. 4 Abbreviations and Acronyms 5 Nomenclature..... 6 Definitions..… 6 Table of Contents.… 7 List of Figures. 9 List of Tables. 10 1.0 Introduction..… 11 1.1 Science and Mission Basis............. 11 1.2 Definition and Purpose.................. 13 2.0 Problem Description and Background. 14 2.1 Planetary Exploration Challenges 14 2.1.1 Available Power............. 14 2.1.2 Propulsion Requirements.................. 15 2.1.3 Energy,Power,Mass and Time......... 17 2.1.4 Potential Missions for Nuclear Electric Propulsion. 18 2.2 Architectural Challenges..... 20 2.3 Fundamentals of Nuclear Electric Propulsion 21 2.4 Approach and Thesis Structure.............. 24 3.0 Review of Progress in Nuclear Electric Propulsion 26 3.1 Historical Context of Nuclear Space Systems....... 26 3.2 Recent and Relevant Program Results.... 30 4.0 Definition of Architectural Space and Influences.............................. 32 4.1D0main0 f Study.… 32 4.2 Functional Decomposition.. 34 4.3 Emergence of Form......... 38 4.4 NEPP Domain and Functional Interrelationships. 39 4.5 Determination of Top Level System Goals and Objectives 44 4.6 Architectural Framework................ 45 4.6.1 Safety and Regulation........... 46 4.6.2 Corporate Strategy.............. 49 4.6.3 Competition..... 52 4.6.4 Customer and Market Strategy 55 4.6.5 Technology. 58 4.6.6 Downstream Influences................... 61 4.6.7 Legacy and Current Capability............. 62 5.0 Expanded Sets of Candidate Architectures.. 64 5.1 Description of Concepts and Components. 64 5.1.1 Nuclear Reactors.............. 64Table of Contents Acknowledgements............................................................................................................. 4 Abbreviations and Acronyms ............................................................................................. 5 Nomenclature...................................................................................................................... 6 Definitions .......................................................................................................................... 6 Table of Contents................................................................................................................ 7 List of Figures..................................................................................................................... 9 List of Tables.................................................................................................................... 10 1.0 Introduction................................................................................................................. 11 1.1 Science and Mission Basis...................................................................................... 11 1.2 Definition and Purpose ........................................................................................... 13 2.0 Problem Description and Background........................................................................ 14 2.1 Planetary Exploration Challenges........................................................................... 14 2.1.1 Available Power............................................................................................... 14 2.1.2 Propulsion Requirements................................................................................. 15 2.1.3 Energy, Power, Mass and Time ....................................................................... 17 2.1.4 Potential Missions for Nuclear Electric Propulsion......................................... 18 2.2 Architectural Challenges......................................................................................... 20 2.3 Fundamentals of Nuclear Electric Propulsion ........................................................ 21 2.4 Approach and Thesis Structure............................................................................... 24 3.0 Review of Progress in Nuclear Electric Propulsion.................................................... 26 3.1 Historical Context of Nuclear Space Systems........................................................ 26 3.2 Recent and Relevant Program Results.................................................................... 30 4.0 Definition of Architectural Space and Influences....................................................... 32 4.1 Domain of Study..................................................................................................... 32 4.2 Functional Decomposition...................................................................................... 34 4.3 Emergence of Form................................................................................................. 38 4.4 NEPP Domain and Functional Interrelationships................................................... 39 4.5 Determination of Top Level System Goals and Objectives.................................... 44 4.6 Architectural Framework........................................................................................ 45 4.6.1 Safety and Regulation...................................................................................... 46 4.6.2 Corporate Strategy ........................................................................................... 49 4.6.3 Competition...................................................................................................... 52 4.6.4 Customer and Market Strategy ........................................................................ 55 4.6.5 Technology ...................................................................................................... 58 4.6.6 Downstream Influences ................................................................................... 61 4.6.7 Legacy and Current Capability ........................................................................ 62 5.0 Expanded Sets of Candidate Architectures................................................................. 64 5.1 Description of Concepts and Components.............................................................. 64 5.1.1 Nuclear Reactors.............................................................................................. 64 7