Debris Mitigation, Assembly, Integration, and Test, in the Context of the Istsat-1 Project
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Debris Mitigation, Assembly, Integration, and Test, in the context of the ISTsat-1 project Paulo Luís Granja Macedo Thesis to obtain the Master of Science Degree in Aerospace Engineering Supervisors: Prof. Paulo Jorge Soares Gil Prof. Agostinho Rui Alves da Fonseca Examination Committee Chairperson: Prof. José Fernando Alves da Silva Supervisor: Prof. Paulo Jorge Soares Gil Member of the Committee: Prof. Elsa Maria Pires Henriques November 2018 ii Dedicado ao meu Pai, Mae˜ e Irma˜ iii iv Acknowledgments I want to thank my supervisors, Professor Paulo Gil and Professor Agostinho Fonseca, for guiding me thorough the project. I also want to thank the ISTsat-1 team members, both professors and students, for giving me the opportunity to be part of such a great project and for the availability they had for my questions. The project would not happen if we did not have the University help and the ESA initiative Fly Your Satellite. I want to thank both organizations, that provided and will keep providing financial support, development rooms, test facilities and expertise in Space related matters. I want to thank all the other people that helped me through this phase, my fiends and girlfriend, thank you. Tambem´ quero agradecer aos meus pais e irma,˜ que me ajudaram em tudo o que foi preciso para chegar a este dia, sem eles nao˜ seria poss´ıvel. Obrigado. v vi Resumo O ISTsat-1 e´ um CubeSat desenvolvido por estudantes e professores do Instituto Superior Tecnico´ (IST), com a ajuda de um programa da ESA chamado Fly Your Satellite (FYS). O objectivo principal e´ educar estudantes em cienciaˆ e tecnologia espacial. A missao˜ e´ de estudar a viabilidade de uma antena plana com elevado campo de visao,˜ que recebe sinais ADS-B de aeronaves. O ambiente onde o CubeSat ira´ orbitar faz com este seja suscept´ıvel a erros mecanicosˆ e electricos,´ por isso planos de qualidade terao˜ de ser implementados. Estes providenciam confianc¸a que o sistema cumpre os requisitos de missao,˜ atraves´ de planeamento e implementac¸ao˜ de metodos.´ O objectivo desta tese e´ de detalhar esses planos. Um desses planos mitiga a criac¸ao˜ de lixo espacial. Este e´ efeito secundario´ da explorac¸ao˜ espacial. A implementac¸ao˜ deste plano e´ essencial para assegurar um futuro seguro para satelites´ que orbitam a Terra e pessoas que exploram o Espac¸o. Outro elemento crucial para o sucesso de uma missao˜ espacial e´ a sua montagem, integrac¸ao˜ e verificac¸ao.˜ Este plano foi implementado de acordo com os padroes˜ da industria´ espacial, e in- cluem verificac¸oes˜ ao n´ıvel do componente, subsistema e sistema, tanto em condic¸oes˜ terrestres, de lanc¸amento e espaciais. Finalmente, o procedimento de montagem e integrac¸ao˜ para o CubeSat foi detalhado. O trabalho realizado e´ um plano de montagem e verificac¸ao,˜ podendo ser reutilizado em futuros projetos com o mesmo ambito.ˆ Palavras-chave: ISTsat-1, CubeSat, Lixo Espacial, Montagem, Integrac¸ao,˜ Verificac¸ao˜ vii viii Abstract The ISTsat-1 is a 1U CubeSat developed by students and professors of Instituto Superior Tecnico´ (IST), with the help from an ESA backed program called Fly Your Satellite (FYS). Its main goal is to educate students into space science and technology. The mission is to perform a feasibility study of a wide field-of-view patch antenna built at IST, which receives ADS-B signals from aircraft. The space environment makes spacecraft susceptible to functional and mechanical failures, so qual- ity assurance plans shall be considered. They provide confidence that the design fulfils all mission requirements, by planning and implementing verification methods. This Thesis scope is to provide such quality assurance plans. One of those plans mitigates the creation of space debris. They have become an unintended side- effect of space exploration. These measures are essential to ensure a safe future for the spacecraft orbiting the Earth and the Humans that choose to explore it. Another crucial element for a spacecraft program success is its assembly, integration and verification phase. This plan was implemented according to space industry standards, that included verification at component, subsystem and system level, and at ambient, launch and environmental conditions. Finally, the assembly and integration procedure was detailed. It provides a step-by-step procedure of the final CubeSat assembly. The plan provides details about equipment, handling and wiring. The work performed plans the assembly and verification campaign, and can be reused for future CubeSat projects with the same scope. Keywords: ISTsat-1, CubeSat, Space Debris, Assembly, Integration, Verification ix x Contents Acknowledgments...........................................v Resumo................................................. vii Abstract................................................. ix List of Tables.............................................. xv List of Figures............................................. xvii List of Acronyms............................................ xix 1 Introduction 1 1.1 The ISTsat-1 Mission......................................1 1.2 Scope...............................................1 1.3 Small Satellites..........................................2 1.4 CubeSat Subsystems......................................4 1.4.1 Attitude Determination and Control System......................4 1.4.2 Command and Data Handling..............................6 1.4.3 Communications.....................................7 1.4.4 Electric Power System.................................8 1.4.5 Payload..........................................9 1.4.6 Propulsion........................................9 1.4.7 Structure and Mechanisms............................... 10 1.4.8 Thermal Control..................................... 11 1.4.9 Ground Segment and Operations............................ 12 1.4.10 Launch Vehicles..................................... 12 1.5 Space Debris Mitigation..................................... 13 1.6 Assembly, Integration and Verification Plan.......................... 15 2 Verification of Nanosatellites 17 2.1 Space Debris Mitigation..................................... 18 2.2 Assembly, Integration and Verification plan........................... 19 2.2.1 Quality Assurance on CubeSats............................ 20 2.2.2 Model Philosophy.................................... 21 2.2.3 Verification Methods................................... 21 xi 2.2.4 Verification Stages.................................... 22 2.2.5 Verification Levels.................................... 23 2.2.6 Non conformance.................................... 28 2.3 Assembly and Integration Plan................................. 29 3 ISTsat-1 Development 31 3.1 Operational modes........................................ 31 3.2 Subsystems............................................ 32 3.2.1 On Board Computer (OBC)............................... 32 3.2.2 Communications (COM)................................. 33 3.2.3 Electric Power System (EPS).............................. 33 3.2.4 Structure and Mechanisms (STR)........................... 34 3.2.5 Payload (PL)....................................... 35 3.2.6 ADS-B antenna...................................... 36 3.2.7 Telemetry, Tracking and Command (TTC)....................... 36 3.2.8 U/V antenna....................................... 37 3.2.9 Thermal Control (TC).................................. 37 4 Space Debris Mitigation 39 4.1 Scope and purpose....................................... 39 4.2 Mission profile.......................................... 40 4.3 Space system description.................................... 42 4.4 Mitigation compliance verification................................ 42 4.4.1 Mission-related objects................................. 42 4.4.2 Fragmentation and explosion risk............................ 43 4.4.3 Pyrotechnic particle release............................... 43 4.4.4 On-orbit collision risk................................... 43 4.4.5 Disposal.......................................... 45 4.4.6 Passivation........................................ 46 4.4.7 Re-entry.......................................... 46 4.5 Discussion............................................ 47 5 Assembly, Integration and Verification Plan 49 5.1 Model Philosophy......................................... 50 5.2 Verification Facilities....................................... 51 5.3 Verification on Subsystem Level................................ 51 5.3.1 Soldering......................................... 51 5.3.2 Conformal Coating.................................... 52 5.3.3 Anodization and Thermal Cycling............................ 52 5.3.4 Battery.......................................... 53 xii 5.3.5 ADS-B antenna...................................... 57 5.3.6 U/V antennas....................................... 58 5.3.7 ADCS calibration..................................... 58 5.3.8 Flat-sat.......................................... 59 5.3.9 Other subsystem verification.............................. 59 5.4 Verification on System Level................................... 59 5.4.1 Physical Properties................................... 60 5.4.2 ADCS Characterization................................. 60 5.4.3 Full Functional Test................................... 61 5.4.4 Reduced Functional Test................................ 63 5.4.5 Mission Test....................................... 63 5.4.6 End-to-end Test..................................... 65 5.4.7 Mechanical Testing.................................... 65 5.4.8