Multiple Asteroid Retrieval Mission Gustavo Gargioni Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science in Aerospace Engineering Jonathan T Black, Chair Shane D Ross Scott L England May 11, 2020 Blacksburg, Virginia Keywords: Near-Earth Objects, Asteroid, S-Type, M-Type, Close Approach, Relative Velocity, Asteroid Return Mission, API, L2-Halo, Hohmann, Manifold, Absolute Magnitude, Albedo, BFR, Starship, Tanker, Spacecraft Reusability, Rocket Reusability, in-space refueling, CNEOS, JPL, NASA, KISS, Cislunar, Gateway Copyright 2020, Gustavo Gargioni Multiple Asteroid Retrieval Mission Gustavo Gargioni (ABSTRACT) In this thesis, the possibility of enabling space-mining for the upcoming decade is explored. Making use of recently-proven reusable rockets, we envision a fleet of spacecraft capable of reaching Near-Earth asteroids. To analyze this idea, the goal of this problem is to maximize the asteroid mass retrieved within a spacecraft max life span. Explicitly, the maximum lifetime of the spacecraft fleet is set at 30 years. A fuel supply-chain is proposed and designed so that each spacecraft is refueled before departing for each asteroid. To maximize access to the number of asteroids and retrievable mass for each mission, we propose launching each mission from an orbit with low escape velocity. The L2-Halo orbit at the libration point in the Earth-Moon system was selected due to its easy access from Low-Earth Orbit and for a cislunar synergy with NASA Gateway. Using data from NASA SmallBody and CNEOS databases, we investigated NEAs in the period between 2030 and 2060 could be captured in the ecliptic plane and returned to L2-Halo with two approaches, MARM-1 and MARM- 2. Together, these databases provide all information for every asteroid’s close approach known today. Returning the asteroid as a whole is explored in the MARM-1 method, while MARM-2 evaluates the possibility of reaching larger asteroids and returning a fragment of their masses, such that it optimizes the available cargo weight per time of flight of each mission. The following results are compared with previous work from the community. The results show a 96% reduction in the cost per kg, with an enormous increase in retrieved mass. With these results, this thesis shows that not solely energy or dynamic optimization will be responsible for proving space mining feasibility, but rather a combination of those and business best practices. Proving feasibility for space mining is a complex and immense problem. Although this thesis opens new possibilities for future work on the field and sparkes the interest of private endeavors, the final solution for this problem still requires additional exploration. Multiple Asteroid Retrieval Mission Gustavo Gargioni (GENERAL AUDIENCE ABSTRACT) In this thesis, the possibility of enabling space-mining for the upcoming decade is explored. Making use of recently-proven reusable rockets, we envision a fleet of spacecraft capable of reaching Near-Earth asteroids, NEAs. To analyze this idea, the goal of this problem is to maximize the asteroid mass retrieved within a spacecraft max life span. Explicitly, the maximum lifetime of the spacecraft fleet is set at 30 years. A fuel supply-chain is proposed and designed so that each spacecraft is refueled before departing for each asteroid. To maximize access to the number of asteroids and retrievable mass for each mission, we propose launching each mission from an orbit with low escape velocity. A location after the Moon, at the L2-Halo orbit, was selected due to its easy access from Low-Earth Orbit and for a synergy with the proposed new space station at the Moon orbit. Using data from NASA databases, we investigated the asteroids in the period between 2030 and 2060 that could be captured and returned with two approaches, MARM-1 and MARM-2. Together, these databases provide all information for every asteroid’s close approach known today. Returning the asteroid as a whole is explored in the MARM-1 method, while MARM-2 evaluates the possibility of reaching larger asteroids and returning a fragment of their masses, such that it optimizes the available cargo weight per time of flight of each mission. The following results are compared with previous work from the community. The results show a 96% reduction in the cost per kg, with an enormous increase in retrieved mass. With these results, this thesis shows that not solely energy or dynamic optimization will be responsible for proving space mining feasibility, but rather a combination of those and business best practices. Proving feasibility for space mining is a complex and immense problem. Although this thesis opens new possibilities for future work on the field and sparkes the interest of private endeavors, the final solution for this problem still requires additional exploration. v Dedication to my wife and kids for their love and support during graduate school. I could not have concluded this work without you, thank you. to my parents that forged me believing that nothing is unreachable if you desire and work sedulously. vi Acknowledgments I want to thank my advisor, Dr. Jonathan Black, for his support and counsel. I am grateful for my other two committee members, Dr. Shane Ross and Dr. Scott England. For all staff and faculty from Space@VT and the Hume Center, I would like to mention that you made all the difference. Your dedication and care are incommensurate; thank you so much. I would also like to thank my department, the Aerospace and Ocean Engineering Department, for supporting this thesis, unique to its fantastic staff that guided me along the way. And, finally, a special thanks to my friend Marco Peterson for his support and guidance, for the long hours spent encouraging me through the difficult times. vii Contents List of Figures x List of Tables xiv 1 Introduction 1 1.1 Motivation ..................................... 1 1.2 The Earth mining market ............................ 5 1.2.1 CAPEX .................................. 7 1.2.2 Contemporary mining availability .................... 8 1.3 Space mining overview .............................. 9 1.4 Case for Near Earth Asteroids .......................... 11 1.5 Case for L2-Halo ................................. 15 1.6 Case for SpaceX’s Starship ............................ 19 1.7 Introduction Summary .............................. 24 2 Problem Definition 26 2.1 Asteroid Size and Density ............................ 27 2.2 Near-Earth Asteroid Data Consolidation .................... 31 2.3 MARM 1 Method ................................. 36 viii 2.4 MARM 2 Method ................................. 41 2.5 Fuel supply-chain ................................. 49 2.6 Review of Literature and Previous Missions .................. 56 3 Result and Analysis 60 3.1 Number of Available Close Approaches ..................... 60 3.2 MARM 1 - Results ................................ 63 3.3 MARM 2 - Results ................................ 71 3.4 MARM Cost Analysis .............................. 79 3.5 Results Summary ................................. 85 4 Conclusions and Future Work 87 Bibliography 93 Appendices 99 Appendix A First Appendix 100 A.1 Section one .................................... 100 A.2 Section two .................................... 130 A.3 Section three ................................... 157 Appendix B Second Appendix 179 ix List of Figures 1.1 NASA Inflation-Adjusted Budget and Share of U.S. Federal Budget from 1967 to 2018. [14] .................................... 2 1.2 Market Share of the top 25 companies, from the Earth-based mining industry in 2017. ...................................... 6 1.3 Evolution of CAPEX for the Earth-based mining industry over the last 6 years. 7 1.4 The Space-mining process envisioned in comparison with Earth’s mining process 10 1.5 Center for Near Earth Objects Studies discoveries in the last 30 years, up to March 26 of 2020. This chart shows the total quantity of NEAs discovered classified by their size in diameter (m). ..................... 12 1.6 Percentage Distribution from Quantity of NEAs by Group of Asteroid along- side with distance profile for Earth’s close approaches. ............ 13 1.7 DeltaV required to escape Earth’s SOI x distance from Earth on a log10 scale. 17 1.8 Lagrange points in the Earth-Moon system ................... 18 1.9 BFR system presented by E. Musk in the 2017 International Astronautical Congress. This chart shows its 150 metric ton payload capability to LEO com- pared to current SpaceX’s rocket launch systems, such as the Falcon Heavy with 30 metric ton and Falcon 9 with 15 metric ton. .............. 20 x 1.10 BFR system presented by E. Musk in the 2017 International Astronautical Congress. This chart shows its refilling capability. Here it is presented a Tanker BFR refueling a Spacecraft BFR using a control thrusters milli-g ac- celeration to transfer the fuel. .......................... 21 1.11 SpaceX’s Starship payload delivery [38]. .................... 22 2.1 This diagram show the method used to combine segregated information from Near-Earh Objects from CNEOS and Small-Body databases into a single Data Preparation point in a Google SpreadSheet ................... 33 2.2 This diagram show the method used to combine segregated information from Near-Earh Objects from CNEOS and Small-Body databases into a single Data Preparation point in a Google SpreadSheet ................... 34 2.3 Conceptual