ON-ORBIT SERVICEABILITY OF SPACE SYSTEM ARCHITECTURES by Matthew G. Richards S.B. Aeronautics and Astronautics – Massachusetts Institute of Technology, 2004 Submitted to the Department of Aeronautics and Astronautics and the Engineering Systems Division in Partial Fulfillment of the Requirements for the degrees of Master of Science in AERONAUTICS AND ASTRONAUTICS and Master of Science in TECHNOLOGY AND POLICY at the Massachusetts Institute of Technology June 2006 © 2006 Massachusetts Institute of Technology All rights reserved Signature of Author……………………………………………………….………………………................. Department of Aeronautics and Astronautics Engineering Systems Division May 19, 2006 Certified by…………………………………………………….…………………………………................. Daniel E. Hastings Professor of Aeronautics and Astronautics and Engineering Systems Dean for Undergraduate Education Thesis Supervisor Certified by…………………………………………………….…………………………………................. Donna H. Rhodes Senior Lecturer of Engineering Systems Thesis Supervisor Accepted by…………………………………...……………………………………………………………... Dava J. Newman Professor of Aeronautics and Astronautics and Engineering Systems Director, Technology and Policy Program Accepted by……………...…………………………………………………………………………………... Jaime Peraire Professor of Aeronautics and Astronautics Chair, Committee on Graduate Students 2 ON-ORBIT SERVICEABILITY OF SPACE SYSTEM ARCHITECTURES by Matthew G. Richards Submitted to the Department of Aeronautics and Astronautics and Engineering Systems Division on May 19, 2006 in Partial Fulfillment of the Requirements for the Degrees of Master of Science in Aeronautics and Astronautics and Master of Science in Technology and Policy. Abstract On-orbit servicing is the process of improving a space-based capability through a combination of in-orbit activities which may include inspection; rendezvous and docking; and value-added modifications to a satellite’s position, orientation, and operational status. As a means to extend the useful life or operational flexibility of spacecraft, on-orbit servicing constitutes one pathway to a responsive space enterprise. Following launch, traditional satellite operations are tightly constrained by an inability to access the orbiting vehicle. With the exception of software upgrades from ground controllers, operators are wedded to supporting payload technologies that become rapidly obsolete and to bus structures that deform during the stress of launch and degrade in the harsh environment of space. On-orbit servicing offers satellite operators an option for maintaining or improving space-based capabilities without launching a new spacecraft. Numerous studies have been performed on on-orbit servicing, particularly regarding the architecture of the servicing provider. Several customer valuation case studies have also been performed to identify the economic case (or lack thereof) for different categories of servicing missions. Little work, however, has been done to analyze the tradespace of potential on-orbit servicing customers—a global analysis of operational satellites currently orbiting the Earth. The goal of this research is to develop and test a methodology to assess the physical amenability of satellites currently in operation to on-orbit servicing. As defined here, physical amenability of a target satellite, or “serviceability,” refers to the relative complexity required of a teleoperated or autonomously controlled robotic vehicle to accomplish on-orbit servicing. A three-step process is followed to perform serviceability assessments. First, a taxonomy of space systems is constructed to add structure to the problem and to identify satellite attributes that drive servicing mission complexity. Second, a methodology is proposed to assess serviceability across the four servicing activities of rendezvous, acquire, access, and service. This includes development of an agent-based model based on orbital transfers as well as a generalized framework in which serviceability is decomposed into four elements: (1) knowledge, (2) scale, (3) precision, and (4) timing. Third, the value of architecture frameworks and systems engineering modeling languages for conducting serviceability assessments is explored through the development of a discrete event simulation of the Hubble Space Telescope. The thesis concludes with prescriptive technical considerations for designing serviceable satellites and a discussion of the political, legal, and financial challenges facing servicing providers. Thesis Supervisors: Daniel E. Hastings, Professor of Aeronautics and Astronautics and Engineering Systems Donna H. Rhodes, Senior Lecturer of Engineering Systems 3 To God for the opportunity, my family for the confidence, and Dr. Wheelon for the inspiration. 4 Acknowledgements Since the first “intellectual scrubbing” I witnessed in one of his group research meetings, I have been fascinated by Professor Hastings, his enjoyable leadership style and his thirst for meeting the challenges of our time. From the freedom he granted me to pursue on-orbit servicing to his rich stories of “fighting fires” down in Washington D.C., I was always challenged and motivated. Working as his research assistant is an intellectual treat and adventure; I look forward to the sequel as I pursue the Ph.D. As my research advisor for the Lean Aerospace Initiative (LAI), Donna Rhodes kept my mind well- nourished with the systems engineering tools and processes that enabled this thesis from both an intellectual and practical perspective. I thank her for her ideas and encouragement. I am also in debt to Professor Weigel, who served as my academic advisor during my first year. As a five-time Shuttle astronaut and Hubble mechanic, I thank Professor Hoffman for his insights as well as his awesome contributions to the practice of on-orbit servicing. This work would not have been possible without the support of the students in Professor Hastings’ research group. Between juggling a wife, four kids, and real options theory, Jason Bartolomei has been a role model to me for every aspect of life: professional, personal, and spiritual. With his quirky sense of humor and an aptitude for making profound insights at the least probable times, Spencer Lewis was a pleasure to turn to during late nights in lab. In addition to being a close friend, Andrew Long is a fellow believer in on-orbit servicing; his Master’s thesis provided a foundation for my own research. From the purposeful mindset he instilled in our research group to the lab he set up, I am grateful to have Adam Ross as one of the “architects” of my graduate school experience, and I look forward to working with him in the future. Finally, Nirav Shah never ceases to amaze me with his casual mastery of such a diverse range of topics; his contributions to this thesis, particularly the modeling activities, are immense. Thank you, Nirav, for making this research possible. Having worked with Michelle McVey and Phil Springmann at DARPA on space tugs, their fingerprints are all over this thesis. Thank you also to Phil for his critical feedback on my work. It would be impossible to acknowledge everyone who has influenced my thinking over my education at MIT, the University of Cambridge, and Campbell Hall School. I would like to thank fellow students David Broniatowski, Heidi Davidz, Nicole Jordan, Pedzi Makumbe, Charlotte Mathieu, Sam Prentice, Darlene Utter, Katie Walter, and Roland Weibel for contributing to my graduate school experience. Having begun my academic research career with LAI in January 2002, I am grateful to Professor Murman, Professor Nightingale, Kirk Bozdogan, Hugh McManus, Eric Rebentisch, and Tom Shields who have each supervised me on various projects. Thanks are due to Rob Perrons, my research supervisor in Cambridge, for his insights regarding servicing offshore oil platforms. I would also like to thank all of my teachers over the years, particularly Gay Seltzer, who reviewed a draft of this thesis. Amy Marshall deserves credit for keeping me sane, both on and off the basketball court. I thank her for her spirit, charm, and contagious enthusiasm for life. I thank my family for their unwavering support and encouragement. To my Dad for his feedback on just about every document that I have ever written, to my Mom for always making me do my best, and to my brother, Michael, for teaching me what it truly means to succeed; thank you for your contributions to my education. 5 Table of Contents ABSTRACT................................................................................................................................... 3 ACKNOWLEDGEMENTS ......................................................................................................... 5 TABLE OF CONTENTS ............................................................................................................. 6 LIST OF FIGURES .................................................................................................................... 10 LIST OF TABLES ...................................................................................................................... 12 ACRONYMS............................................................................................................................... 13 1 INTRODUCTION............................................................................................................... 15 1.1 BACKGROUND................................................................................................................ 17 1.1.1 Complex Systems Problems