Non-cooperative spacecrafts are those current or future assets in orbit which have lost their control authority in one or more degrees of freedom and cannot convey any information concerning their position, attitude or rates to facilitate Rendezvous and Docking/Berthing (RVD/B) process. A growing field of study in space research is to develop On-Orbit Servicing (OOS) technology capable of dealing with these space- crafts, called targets, which are designed without any intention to be serviced. To render services such as repair, refuel or removal of the target from orbit, the chaser spacecraft should exhibit sophisticated RVD/B technology for formation fly and final stage docking/berthing operations of the mission. Assuming that the terminal capture operations of the target are to be performed by a suitable manipulator system on-board chaser, this study relies upon proven technology and outlines guidance and control methodologies to achieve rendezvous during proximity phases. The entry gate of chaser after phasing can be defined at a distance of about 5 km in ± V-bar direction from the target in its orbit. To account for errors in modeling, navigation or actuation, proximity range operations from the entry gate are decomposed into three different subphases as far range, inspection or fly around and closer approach. From the entry gate and along the path of the chaser two hold points are defined: first to initiate an inspection and the second, which is close to the safe zone defined around the target, to initiate a capture. The chaser is assumed to perform a station keeping maneuver at the second hold point until initial conditions for the capture are met. Possible scenarios pertaining to the behavior of the target in a circular orbit are considered and guidance schemes for different subphases are presented using a combination of Hill-Clohessy-Willtshire (HCW) solution, elliptical fly around, glides- lope algorithm etc. Relative controllers both for position and attitude of the chaser are also presented. A Linear Quadratic (LQ) controller for relative position and a Proportional Integral Derivative (PID) controller for relative attitude with angular velocity constraints are chosen to track down the error to achieve rendezvous and attitude synchronization with the non-cooperative target. A comparative analysis between different guidance trajectories for important parameters such as time, fuel usage, minimum absolute distance and the maximum radial distance from the target is presented. Verification of the proposed guidance and control methods is done by applying them to two different case studies: the first study incorporating a stabilized target in Geostationary Earth Orbit (GEO) and the second, with a spinning target in Low Earth Orbit (LEO). The methods presented here are general and provide a simulator to the chaser to perform rendezvous analysis with non-cooperative targets. To achieve RVD/B, the study proposes a careful combination of guidance solutions for different phases of proximity operations, and for different scenario’s of the target encountered by the chaser.

Zusammenfassung: This conference attracts GN&C specialists from across the globe. The 2022 Conference was the 44th Annual GN&C conference with more than 230 attendees from six different countries with 44 companies and 28 universities represented. The conference presented more than 100 presentations and 16 posters across 18 topics. This year, the planning committee wanted to continue a focus on networking and collaboration hoping to inspire innovation through the intersection of diverse ideas. These proceedings present the relevant topics of the day while keeping our more popular and well-attended sessions as cornerstones from year to year. Several new topics including "Autonomous Control of Multiple Vehicles" and "Results and Experiences from OSIRIS-REx" were directly influenced by advancements in our industry. In the end, the 44th Annual GN&C conference became a timely reflection of the current state of the GN&C ins the space industry. The annual American Astronautical Society Rocky Mountain Guidance, Navigation and Control (GN&C) Conference began 1977 as an informal exchange of ideas and reports of achievements among guidance and control specialists local to the Colorado area. Bud Gates, Don Parsons, and Bob Culp organized the first conference, and began the annual series of meetings the following winter. In March 1978, the First Annual Rocky Mountain Guidance and Control Conference met at Keystone, Colorado. It met there for eighteen years, moving to Breckenridge in 1996 where it has been for over 25 years

While a paradigm shift in space industry has already started involving “mass production” of higher standardized, large distributed systems such as constellations, there are no effective solutions existing for the “mass removal” of satellites. Many indicators point to a further increase in the space traffic in Earth orbit in the near future, which could imply new dynamics in the evolution of the space debris environment. Even in case of diligent compliance with the Inter-Agency Space Debris Coordination Committee (IADC) mitigation guidelines, the growth in space traffic complicates its management and drastically increases the probability of accidents and system failures. NASA scientist Donald J. Kessler proposed a scenario in which the density of objects in low Earth orbit is high enough that collisions between objects could cause a cascade that renders space unusable for many generations. Therefore, a reliable and affordable capability of removing or servicing non-functional objects is essential to guarantee sustainable access to Earth orbit. Recently, the CubeSat design standard introduced a new class of cost-efficient small spacecraft and thereby offers a potential solution to the active debris removal (ADR) problem. The development of a novel “CubeSat-compatible” ADR technology has significant advantages such as the use of commercial off-the-shelf parts, reduced launch cost, and reduced design efforts. This thesis presents –in the frame of an ADR mission– an approach to advanced rendezvous and docking with non-cooperative targets via CubeSat. It covers the design process of simulation systems used for verification purposes, the ideation and implementation of novel guidance, control, and docking techniques, as well as their verification and evaluation. The outcome of this research is a series of validated software tools, processes, technical devices, and algorithms for automated approach and docking, that have been tested in simulation and with prototype hardware.