In the context of Human Spaceflight exploration mission scenario, with the Deep Space Gateway (DSG) on a Near Rectilinear Halo Orbit (NRHO) about Earth-Moon Lagrangian Point (EML), Rendezvous and Docking (RVD) operational activities are mandatory and critical for assembly of the DSG to be performed by the Orion spacecraft. Orion will also handle cargo delivery and crew exchange missions and they all require RVD. There is extensive experience with RVD in the two-body problem in Low Earth Orbit to various space stations or around Low Lunar Orbit quasi circular, the latter by Apollo in manual RVD. Despite that no operational RVD has yet been performed in the vicinity of the Lagrangian points, where Keplerian dynamics is not applicable. There are some drawbacks from the complexity, but also some strong advantages that need to be researched in depth by the work proposed here. Despite vast literature on families of trajectories about the Lagrangian points and transfers in the Cis-Lunar realm, the scientific community has, at the moment, very few relevant research results in the non Keplerian dynamic domain. However, in recent years one can be seen the emergence of some sparse publications on the subject, which can be explained by the studies related to DSG and Orion missions. Within the partners, semi-analytical tools have been developed to compute and model families of orbits like NRHO, DRO, Lyapunov, Halo and Lissajous about the Lagrangian points in the Circular Restricted Three Body Problem (CR3BP). Hence there is a good starting point for the research for the overall rendezvous strategy considering vehicle and operations constraints. The proposed PhD project is expected to further and strengthen the work already carried out and some of the celestial mechanics tools developed. Further to that research shall be performed regarding the GNC design for such missions and the accuracies that can be achieved with today technologies and what is required. Assuming the DSG to be the target, RVD will be performed in this project by visiting vehicles arriving from the Earth.

The new age space value chain is a complex interconnected system with diverse actors, which involves cross-sector and cross-border collaborations. This book helps to enrich the knowledge of Artificial Intelligence (AI) across the value chain in the space-related domains. Advancements of AI and Machine Learning have impactfully supported the space sector transformation as it is shown in the book. "This book embarks on a journey through the fascinating realm of AI in space, exploring its profound implications, emerging trends, and transformative potential." Prof. Dr. Oliver Ullrich - Director Innovation Cluster Space and Aviaton (UZH Space Hub), University of Zurich, Switzerland Aimed at space engineers, risk analysts, policy makers, technical experts and non-specialists, this book demonstrates insights into the implementation of AI in the space sector, alongside its limitations and use-case examples. It covers diverse AI-related topics applicable to space technologies or space big data such as AI-based technologies for improving Earth Observation big data, AI for space robotics exploration, AI for astrophysics, AI for emerging in-orbit servicing market, and AI for space tourism safety improvement. Key Features: Provides an interdisciplinary approach, with chapter contributions from expert teams working in the governmental or private space sectors, with valuable contributions from computer scientists and legal experts Presents insights into AI implementation and how to unlock AI technologies in the field Up-to-date with the latest developments and cutting-edge applications

The research presented in this dissertation aims at characterizing the relative motion between spacecraft in periodic orbits in the circular restricted three-body problem. Proximity operations maneuvers, such as rendezvous and station-keeping, are approximated using a semi-analytical approach, i.e. by combining the analytical approximation of the nominal periodic orbit of the targeted spacecraft or targeted orbital location with simplified equations of motion that are derived by assuming that the chasing spacecraft and target (or targeted location) are always "close" to each other. The presented method is compared to the "exact" solutions obtained by numerically integrating the non-linear equations of motion of the circular restricted three-body problem. Orbit propagation examples, i.e. control-free trajectories, are shown along with proximity operation maneuvers for which delta-v's are computed. Suitable initial conditions for proximity operations are also computed based on known orbital transfers to specific orbits of interest, including halo orbits and distant retrograde orbits in the Earth-Moon and Mars-Phobos systems. Propellant-optimal results are found and compared to nearby local minima for a given set of time constraints in order to find a maneuver that allows for flexibility regarding departure and arrival time along with contingency plans. This approximation is validated against the use of the more computationally expensive full nonlinear equations of motion of the three-body problem and the "area of applicability" of this method is defined based on a metric that takes into account the initial conditions used when initiating proximity operations and the time-of-flight required to accomplish such maneuvers. Sample results for the Earth-Moon and Mars-Phobos systems are presented for cis-lunar and cis-Martian orbits of interest. The implementation of this method in pre-phase A mission design is also demonstrated in a sample end-to-end Earth-to-Mars mission. The method presented in this dissertation is shown to accurately describe the control-free relative motion between spacecraft in addition to being able to predict the necessary delta-v maneuvers for various proximity operations. Additionally, this method requires less computational time than full numerical methods while being able to assess its accuracy and the validity of the results obtained. Limitations of this method are imposed on the initial relative position between spacecraft as a function of the time required to accomplish proximity operation maneuvers.

Recent space missions rely more and more on the cooperation between different spacecraft in order to achieve a desired objective. Among the spacecraft proximity operations, the orbital rendezvous is a classical example that has generated a large amount of studies since the beginning of the space exploration. However, the motivations and objectives for the proximity operations have considerably changed. The need for higher autonomy, better security and lower costs prompts for the development of new guidance and control algorithms. The presence of different types of constraints and physical limitations also contributes to the increased complexity of the problem. In this challenging context, this dissertation represents a contribution to the development of new spacecraft guidance and control algorithms. The works presented in this dissertation are based on a structural analysis of the spacecraft relative dynamics. Using a simplified model, a new set of parametric expressions is developed for the relative motion. This parametrization is very well suited for the analysis of the geometric properties of periodic relative trajectories and for handling different types of state constraints. A formal connection is evidenced between the set of parameters that define constrained trajectories and the cone of positive semi-definite matrices. This result is exploited in the design of spacecraft relative trajectories for proximity operations, in the impulsive control framework. The resulting guidance algorithms enable the guaranteed continuous constraints satisfaction, while still relying on semi-definite programming tools. The problem of the robustness of the computed maneuvers with respect to navigation uncertainties is also addressed.

This book focuses on the theory and design methods for guidance, navigation, and control (GNC) in the context of spacecraft rendezvous and docking (RVD). The position and attitude dynamics and kinematics equations for RVD are presented systematically in accordance with several different coordinate systems, including elliptical orbital frame, and recommendations are supplied on which of these equations to use in different phases of RVD. The book subsequently explains the basic principles and relative navigation algorithms of RVD sensors such as GNSS, radar, and camera-type RVD sensors. It also provides guidance algorithms and schemes for different phases of RVD, including the latest research advances in rapid RVD. In turn, the book presents a detailed introduction to intelligent adaptive control and proposes corresponding theoretical approaches to thruster configuration and control allocation for RVD. Emphasis is placed on the design method of active and passive trajectory protection in different phases of RVD, and on the safety design of the RVD mission as a whole. For purposes of verification, the Shenzhou spacecraft’s in-orbit flight mission is introduced as well. All issues addressed are described and explained from basic principles to detailed engineering methods and examples, providing aerospace engineers and students both a basic understanding of, and numerous practical engineering methods for, GNC system design in RVD.

Satellites at geosynchronous orbital altitudes are highly valuable for national defense, but are also difficult to access and monitor. Uncrewed inspection spacecraft could supervise various essential defense platforms and deter covert rendezvous by adversaries with malicious intent. 'Neighborhood watch' satellites tasked with this situational awareness mission should be designed and operated in such a way as to maximize their lifespan and efficacy. Motivated by this requirement, this thesis explores the prolonged medium- to close-range spacecraft proximity operations problem from the perspective of continuous optimal trajectory control. A numerical optimization framework is presented for developing and analyzing fuel-, energy-, and time-optimal trajectories with multiple phases using Gauss pseudospectral collocation software. Emphasis is placed on energy efficiency during inspection, for which accurate dynamical models play a critical role in formationkeeping fuel consumption. Various scenarios are analyzed for minimum-energy solutions, such as tactical phasing and insertion into periodic trajectories, avoidance of 'no-fly' zones, inclusion of coupling attitude dynamics, and operations with highly-eccentric targets. This thesis focuses primarily on proximity operations carried out in geosynchronous orbital regimes and neglects orbit perturbations, instead determining the pure cost of linearizing Keplerian gravity using the Hill-Clohessy-Wiltshire model. Error in relative position, angular rate of circumnavigation, and fuel use to enforce linearized periodic trajectories are characterized. It was determined that proximity operations utilizing low-thrust high-specific-impulse solar electric propulsion are well-suited to minimum-energy trajectory optimization with this method. While the contributed analysis tool is not suitable for on-board optimal trajectory generation, it provides a framework to perform useful pre-mission analyses.

This guide instructs users in the operation of a Proximity Operations Planning System. This system uses an interactive graphical method for planning fuel-efficient rendezvous trajectories in the multi-spacecraft environment of the space station and allows the operator to compose a multi-burn transfer trajectory between orbit initial chaser and target trajectories. The available task time (window) of the mission is predetermined and the maneuver is subject to various operational constraints, such as departure, arrival, spatial, plume impingement, and en route passage constraints. The maneuvers are described in terms of the relative motion experienced in a space station centered coordinate system. Both in-orbital plane as well as out-of-orbital plane maneuvering is considered. A number of visual optimization aids are used for assisting the operator in reaching fuel-efficient solutions. These optimization aids are based on the Primer Vector theory. The visual feedback of trajectory shapes, operational constraints, and optimization functions, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool is an example of operator-assisted optimization of nonlinear cost functions. Grunwald, Arthur J. and Ellis, Stephen R. Ames Research Center...