Hybrid Multi-Objective Trajectory Optimization of Low-Thrust Space Mission Design by David Morante Gonz´alez A dissertation submitted by in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Programa Interuniversitario en Mec´anicade Fluidos Universidad Carlos III de Madrid Advisors: Manuel Sanjurjo-Rivo Manuel Soler-Arnedo Tutor: Manuel Sanjurjo-Rivo October 2019 This thesis is distributed under license\Creative Commons Attribution{ Non Commercial { Non Derivatives". Dedicated to M´ıriamFern´andezMata and to my mother iii Acknowledgements This work has been financially supported by Universidad Carlos III de Madrid through a PIF scholarship and has been made possible by the advocacy of several individuals. Firstly, I would like to express my most sincere gratitude to my advisors, Prof. Manuel Sanjurjo and Prof. Manuel Soler. Their guidance, sage advice, commitment, encouragement and understanding have been essential for the completion of the thesis. Thank you Sanjurjo for transmitting your passion and knowledge for Astrodynamics to me, and for always counting on me for the most exotic tasks. Your contribution has been indispensable to achieve the most challenging goals of this thesis. Thank you Soler for transmitting your passion and knowledge for Optimal Control to me, and for teaching me to write scientific documents. Your contribution has been fundamental to find the conductive thread of this thesis. Thank you both for your infinite patience when awaiting me to deliver the first draft. You must have learned that when I say \queda poco" or \ya casi est´a" may imply a several months. In the end, the wait was worth it. Next, I want to thank the remaining members of the ASAP research group. Thank you Dr. Daniel Gonz´alez-Arribas for being a unique office mate and for sharing good moments in and out the office. I will always admire how you always find a solution for every single coding problem and at the same time go to the gym and play tennis. Thank you Prof. Javier Garc´ıa- Heras for showing our group your amazing organizational skills and tools. Although you were once my teacher, now we have proven to make a great team, specially when it has to do with flying quadcopters. Thank you Daniele, Aniel, Eduardo and Nacho for sharing your amazing investigations with me during the research group meetings. I also offer my special thanks to Jos´eManuel S´anchex P´erezand the Mission Analysis pro- fessionals at ESOC for their warm welcome to Darmstadt, where I spent four months. There, I was fortunate to learn how the European Space Agency works and to discuss about the current needs of mission designers at the agency in terms of computational tools. The lessons I learnt there allowed me to make significant improvements related to the application of operational constraints in the algorithms presented herein. Jos´eManuel S´anchex P´erezalways offered ex- cellent input and advice. Besides, you and the people at ESOC, specially the Young Graduate Trainees, made the German winter more enjoyable than expected. My deepest gratitude to Prof. Bruce A. Conway, who supervised my three months stay at the University of Illinois. Thank you Bruce for your continuous help, dedication and support during my internship, which was inspirational and motivating, since you wrote the first book I read to start working with my thesis. Your invaluable feedback has been paramount for the completeness of this work. The lessons I learnt there allowed me to get a deeper insight into the problem of optimizing low-thrust interplanetary trajectories with maneuver scheduling constraints. Thank you Bruce because you made me feel like home in America, and because you let me fly in your plane over Urbana. v A special mention is deserved by Jacob A. Englander, who hosted me at NASA Goddard Spaceflight Center. Thank you Jacob for your continuous fights with the administration to get me there. Although I only spent one month within your team, it was one of the most amazing experiences I have ever lived, personally and professionally. I was fortunate to use the algorithms I had implemented for my thesis to prepare a proposal for a real mission within a team of renowned professionals. The lessons I learnt there allowed me to significantly enhance the capabilities of the implemented tool. Thank you Jacob because your guiding, advice, knowledge and encouragement is part of this thesis. Many thanks to Javier Roa and to Jes´usPel´aezfor their invaluable assistance and help during the implementation of the generalized logarithmic spirals code. Thank you also to Hodei, Gonzalo and Davide for guiding my first steps of this research venture, while I was a member of the Space Dynamics Group at the Universidad Polit´ecnicade Madrid. Many thanks to my colleagues at the aerospace department at the Universidad Carlos III de Madrid: Marco, Rocco, Luca, Gonzalo, Xin, V´ıctor,Manu, Carlos, Alex,´ Filippo, Alvaro,´ Adri, and the new incorporations. Thank you for your company during lunch and breaks, and because only you can understand what doing PhD thesis implies. Este documento no s´oloes fruto del trabajo realizado durante cuatro a~nosde investigaci´on pre-doctoral y 9 meses escribiendo (s´ı,un embarazo), sino tambi´ende 28 a~nos donde todos y cada uno de mis pasos me han hecho escribir esta tesis doctoral tal y como es. Por ello, nada de esto habr´ıasido posible sin el apoyo incondicional y constante de mi familia. Graci´as,Mam´a, por tu educaci´ony cari~no,por ense~narmeque puedo conseguir todo lo que me proponga a base de esfuerzo, por animarme en los momentos m´asdif´ıcilesy por ense~narmea ser mejor persona. Gracias, Pap´a,por ser mi modelo a seguir, por levantarte todos los d´ıaspara trabajar 12 horas en un bar con el objetivo de darnos lo mejor. Gracias a mi hermanos, Alberto, Jes´usy Paloma (mi ni~na)por ser fieles compa~neros de vida, aventuras y confesiones. En m´ıhay un poco de todos vosotros y por ende en esta tesis. Gracias a mis amigos de siempre, por eso, por seguir ah´ı.Gracias Tania por crear la leyenda del pato-pez, por no permitir que nos robasen los ´organosen Mallorca, por lo bailes de pasillo, por Reina Victoria y por Albacete y por tantas otras cosas que me dar´ıanpara escribir otra tesis. Gracias Rosa por mantenernos a todos siempre informados de cualquier cotilleo que pueda haber. Gracias Ferro por amenizar cualquier ocasi´oncon una bonita (?) canci´on.Gracias Edu, Fran y Yuste porque sin vosotros nuestras reuniones estar´ıanvac´ıas.Mil gracias a todos y cada uno de mis compa~nerosde carrera de ca~nitas: Enrique, Sara, Andrei, Miguel, Paula, Koldo, Marta, Roci, Sergio y Osorio. Gracias porque juntos a vosotros logr´eterminar la carrera que me abri´olas puertas al doctorado, y junto a vosotros consegu´ıescribir esta tesis. Gracias Bea por ense~narmeel mundo amarillo. Gracias a mis amigos de BP: Samu, J. Luis, Alvaro´ y dem´as por ense~narmeque siempre hay vivir apostando el all-in. Gracias a ti, M´ıriam, por ser el pilar fundamental de mi vida. Gracias porque mientras escrib´ıatodas y cada una de las palabras de esta tesis t´uestabas en mi cabeza. Gracias por aguantar todos los contratiempos, por la paciencia, por la compresi´ony por cuidarme. Mil gracias por hacer que escribir est´atesis haya sido mucho m´asf´acil. Gracias por hacerme ver que hay mundo m´asall´adel doctorado y por ofrecerme el punto de vista de una periodista profesional. Gracias por animarme todos los d´ıasa seguir escribiendo y a empujarme siempre m´asalto. Gracias por ser y por estar. No podr´ıacerrar esta secci´onsin poner una mirada en el futuro, el cual tiene nombre de start-up: Ienai SPACE. Gracias Dani, Sara y Mick por permitirme formar parte de esta \as- troaventura" empresarial. Gracias por mostrarme que todas la habilidades y conocimientos adquiridos durante el doctorado pueden tener una aplicaci´onen el sector comercial. Gracias por adentrarme en el fascinante mundo del dise~node motores de propulsi´onel´ectrica.Gracias por ofrecerme la oportunidad de aprender sobre finanzas, ventas o negociaci´oncon inversores. Gracias por creer, por luchar, por ilusionar y por trabajar incansablemente por una idea. Gra- cias por hacer que lo mejor est´ea´unpor venir... Published and Submitted Content The following publications are partially included in the thesis. Journal Papers 1. D. Morante, M. Sanjurjo-Rivo, and M. Soler, \Multi-Objective Low-Thrust Inter- planetary Trajectory Optimization Based on Generalized Logarithmic Spirals", Jour- nal of Guidance, Control, and Dynamics, vol. 42, pp. 476-490, 2019 (https: //doi.org/10.2514/1.G003702). Material from this publication is included mainly in Chapter 3 and Chapter 5 and to a smaller extent in Chapter 1, Chapter 2. Author roles: Daniel Morante (DM) carried out the development and implementation of the method and the analysis of the results; the paper was written by DM with feedback from Sanjurjo-Rivo (MSR) and Manuel Soler (MS). Conference Proceedings 1. D. Morante, M. Sanjurjo-Rivo, and M. Soler, \MOLTO-OR: A Multi-Objective Low- Thrust Optimization Tool for Orbit Raising", in Proceedings of 7th International Conference on Astrodynamics Tools and Techniques (ICATT), nov 2018 (https:// indico.esa.int/event/224/contributions/3859/contribution.pdf). Material from this publication is included mainly in Chapter 4. Author roles: DM carried out the development and implementation of the algorithm and the analysis of the results; the paper was written by DM with feedback from MSR and MS. 2. D. Morante, M. Sanjurjo-Rivo, and M.