STOCHASTIC FEASIBILITY ASSESSMENTS OF ORBITAL PROPELLANT DEPOT AND COMMERCIAL LAUNCH ENABLED SPACE EXPLORATION ARCHITECTURES A Thesis Presented to The Academic Faculty by Patrick R. Chai In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Aerospace Engineering Georgia Institute of Technology December 2014 Copyright c 2014 by Patrick R. Chai STOCHASTIC FEASIBILITY ASSESSMENTS OF ORBITAL PROPELLANT DEPOT AND COMMERCIAL LAUNCH ENABLED SPACE EXPLORATION ARCHITECTURES Approved by: Dr. Alan W. Wilhite, Advisor Dr. Carlee A. Bishop School of Aerospace Engineering Georgia Tech Research Institute Georgia Institute of Technology Georgia Institute of Technology Dr. Brian J. German Dr. David J. Chato School of Aerospace Engineering Propulsion and Propellants Branch Georgia Institute of Technology NASA Glenn Research Center Dr. Mitchell L.R. Walker Date Approved: October 31, 2014 School of Aerospace Engineering Georgia Institute of Technology ACKNOWLEDGEMENTS First and foremost, I would like to thank my advisor, Dr. Alan Wilhite, for his support through my entire graduate career. There have been many times during the past six years when I doubted whether or not I would ever complete the degree, but he always provided enough motivation to keep me going. This dissertation would not have been possible without his continued support and his unwavering belief in me. I would like to acknowledge my colleagues and friends for their support in my academic work. To Dr. Erik Axdhal, Dr. Dale Arney, Christopher Jones, Dr. Rafael Lugo, Dr. Ashley Korzun, and Dr. Brad Steinfeldt - thank you so much for all of your help getting my proposal, dissertation, and defense in order. I couldn’t have done it without you. To my dearest friends Phyllis Petronello, Brent Rivard, Alex Rivard, Mannfred Slotnick, and Dana Notestine - thanks for believing in me. Additionally, I would like to thank Dr. Doug Stanley and the entire Graduate Education staff at the National Institute of Aerospace for their support. Finally, I would like to thank my family for providing me with every opportunity to be successful in life. I am truly blessed to have their support and their love. They say good things in life are worth waiting, sorry it took so long. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS .......................... iii LIST OF TABLES ............................... viii LIST OF FIGURES .............................. xi NOMENCLATURE ............................... xvi SUMMARY .................................... xxiv I INTRODUCTION ............................. 1 1.1 Motivation ................................ 1 1.2 ResearchGoals.............................. 7 1.3 DissertationOutline........................... 9 II BACKGROUND .............................. 12 2.1 PropellantDepotBackground . 13 2.2 RecentLiteratureReview . 15 2.3 PropellantDepotTaxonomy . 22 2.4 PropellantDepotTechnology . 24 2.4.1 CryogenicFluidManagement. 27 2.4.2 PropellantAcquisitionandTransfer . 30 2.4.3 PropellantMassGauging . 34 2.5 PropellantDepotConceptofOperation . 34 2.6 CommercialLaunchIndustry . 38 2.7 Challenges to Propellant Depot Based Architecture . .... 42 III METHODOLOGY ............................. 45 3.1 FeasibilityDefinition .......................... 45 3.1.1 LiteratureReview . 47 3.2 FeasibilityAssessment. 51 3.2.1 PerformanceEvaluation. 51 iv 3.2.2 ReadinessLevels......................... 53 3.2.3 FeasibilityStudyDeficiencies . 56 3.3 StochasticFeasibilityAssessment. .. 59 3.3.1 UncertaintyDefinition. 60 3.3.2 UncertaintyAssessment. 62 3.3.3 Requirements&Constraints . 63 3.4 ArchitectureFeasibility . 65 IV TECHNICAL AND PERFORMANCE FEASIBILITY ASSESS- MENTS .................................... 67 4.1 SpaceThermalEnvironment . 67 4.2 PassiveThermalManagement . 72 4.3 ActiveThermalManagement . 77 4.3.1 CryocoolerLimitationsinSpace . 80 4.3.2 CryocoolerPerformanceEstimation . 81 4.3.3 CryocoolerMassEstimation . 83 4.4 ThermalSystemPerformanceEvaluation . 86 4.4.1 All-PassiveThermalSystemPerformance . 88 4.4.2 Integrated Passive & Active Thermal System Performance.. 91 4.5 ThermalSystemMassTrades. 91 4.5.1 SubsystemSizingandMassEstimation . 93 4.5.2 MassTrades ........................... 96 4.6 Uncertainty Analysis and Probabilistic Simulation . ..... 100 4.7 Summary of Technical Feasibility Assessment . ... 106 V LAUNCH RELIABILITY AND PROPELLANT AGGREGATION FEASIBILITY ASSESSMENT ..................... 108 5.1 HistoricalLaunchReliability . 108 5.2 LaunchVehicleInfancyReliability . 113 5.3 BayesianReliabilityMethod . 120 5.4 Propellant Aggregation Launch Requirements . ... 128 v 5.5 Propellant Aggregation Launch Success Probability . ..... 137 5.6 SummaryofFeasibilityAssessment . 146 VI ARCHITECTURE COST ANALYSIS AND ECONOMIC FEASI- BILITY ASSESSMENT .......................... 148 6.1 SpaceExplorationBudgetConstraints . 148 6.2 BaselineArchitectureExplorationCost . 151 6.3 AlternateArchitectureCostAnalysis . 154 6.3.1 LaunchVehicleCost. 154 6.3.2 UniqueElementCosts. 156 6.3.3 CostEstimationMethodComparison . 165 6.4 TotalArchitectureCostComparison . 168 6.5 Impact of CER Uncertainty in Architecture Cost . 171 6.6 CostofMissionReliability . 174 6.7 Summary of Economic Feasibility Assessment . 177 VII INTEGRATED ARCHITECTURE FEASIBILITY ASSESSMENT179 7.1 StochasticFeasibilityAssessment. 179 7.1.1 Launch Success Feasibility versus Economic Feasibility. 181 7.1.2 Performance Feasibility versus Economic Feasibility ..... 189 7.2 TotalArchitectureFeasibilitySummary . 190 VIIIDISSERTATION SUMMARY AND CONCLUSIONS ....... 198 8.1 ResearchGoals.............................. 198 8.2 Conclusions ............................... 200 8.3 ContributionsandFutureWork . 203 APPENDIX A — SURVEY OF CRYOCOOLERS .......... 206 APPENDIX B — HISTORICAL AEROSPACE SYSTEM MASS DATA ..................................... 213 APPENDIX C — RESULT OF THE FIRST TEN LAUNCHES OF 99 LAUNCH VEHICLE FAMILY ................... 217 vi REFERENCES .................................. 226 vii LIST OF TABLES 1 Human Exploration Framework Team Program Total Cost Estimate inFY11$millionfor2030NearEarthAsteroidMission . 5 2 Breakdown of Assembled Mass in Orbit for Various Human Exploration Missions .................................. 14 3 Assessment of Technologies for a Cryogenic Propellant Depot..... 28 4 Potential Propellant Depot Architecture Design Space . ..... 37 5 U.S. Commercial Launch Vehicle Payload Capability Summary .... 39 6 NASA’sDefinition ofTechnologyReadinessLevels. 54 7 NASA’s Definition of Research & Development Degrees of Difficulty. 55 8 Yearly Average Temperature Experience by a Spherical Node with White Paint Absorptivity and Emissivity Range in a 400 km 28.5o InclinationCircularOrbit . 72 9 Heat Load Through Insulation Comparison between Experimental Data andAnalyticalModel........................... 76 10 MLIMaterialsProperty ......................... 77 11 CryocoolerSubsystemMassBreakdown. 86 12 CryogenicFluidsThermalProperties . 87 13 SummaryofMassEstimatingRelationships . 95 14 Minimal Thermal System Dry Mass for Zero Boil Off for 32 mT of Hydrogenand192mTofOxygen . 98 15 Cryogenic Fluid Management Scenario Description . .... 98 16 Propellant Depot System Dry Mass Breakdown for Different Cryogenic FluidManagementScenarios. 99 17 MER Correction Factor Statistical Analysis Summary . .... 101 18 Nominal Payload Capability to Low Earth Orbit for Various Launch Vehicles .................................. 104 19 Probability of Depot System Dry Mass of Meeting Launch Vehicle PayloadConstraint . 105 20 Summary of the Results of the First Ten Launches for the Family of LaunchVehicleinAppendixC. 115 viii 21 z-Values for Hypothesis Test of the Failure Rates for the First Ten LaunchesofLaunchVehicles . 119 22 Observed Launch Record for Launch Vehicles of Interest and Related Family,throughJanuary31,2014 . 125 23 Summary of the Bayesian Prior and Posterior Distribution for the Four LaunchVehicleofInterest . 128 24 LaunchVehicleUpperStageMassSummary . 130 25 Launch Vehicle Flight Rates for Selected Launch Vehicles ....... 131 26 Breakdown of Average Propellant Aggregation Rates for Each of the Launch Vehicles and Scenarios Assuming a Tanker Oxidizer-to-Fuel Ratioof6 ................................. 133 27 Tanker Required Oxidizer-to-Fuel Ratio for On-Orbit Propellant Ag- gregationOxidizer-to-FuelRatioof6 . 135 28 Total Propellant Aggregation Rates With Optimized Tanker Oxidizer- to-Fuel Ratio Ensuring Final Oxidizer-to-Fuel Ratio of 6 . ..... 136 29 Number of Launches Required to Fill 225 mT Propellant Depot with Tanker Propellant Mass Fraction of 0.87 with Optimized Oxidizer-to- FuelRatio................................. 137 30 Summary of Propellant Aggregation Mission Success Probability in the Zero-Boil-Off Scenario without Launch Redundancy . 140 31 Summary of Propellant Aggregation Launch Success Probability in the Zero-Boil-Off Scenario with Bayesian Launch Reliability . ..... 143 32 U.S.LaunchVehicleLaunchPriceSummary . 155 33 TranscostDevelopmentCostFactors . 160 34 Deterministic Development Cost Summary for Propellant Depot with VariousCryogenicThermalSystems. 163 35 Deterministic Theoretical First Unit Cost Summary for Propellant De- potwithVariousCryogenicThermalSystems . 165 36 Deterministic Development and Theoretical First Unit Cost Summary for Propellant Tankers for Each Launch Vehicles with Propellant Mass Fractionof0.87 .............................. 166 37 Deterministic Development and Unit Cost Summary for Deep Space Habitat, Multi-Mission Space Exploration Vehicle, and