Susanne Peters

ADReS-A: Mission architecture for the removal of SL-8 rocket bodies

The awareness of space debris as a threat for the safe operation of satellites in Earths orbit increased rapidly over the last few years. Attempts such as improving trajectory predictions of non-functional objects in space, guidelines for safer launches nowadays, and post-mission disposal maneuver, however, will not stop the growth in debris numbers, as simulations predict. Mitigation needs therefore the realization of removal missions. This paper introduces an exemplary removal mission for 5 Russian SL-8 rocket bodies at an inclination of 83° orbiting at an altitude of 970 km - an area crowded with space debris and thus involving a high collision risk. By removing large objects, the potential for the creation of smaller fragments due to collisions shall be reduced. The mission itself consists of a main satellite (Autonomous Debris Removal satellite - ADReS-A) and smaller De-orbit Kits being launched together into an orbit close to the targets position. While the De-orbit Kits are equipped with a de-orbit thruster, the task of ADReS-A is, to approach the uncooperative target, perform berthing operations, stabilize the compound system and attach one De-orbit Kit onto the rocket body. The main satellite will take each De-orbit Kit separately to the individual targets, shuttling between the parking orbit and the target orbits. Future investigations concentrate on autonomy for highly critical situations resulting from the interaction with an uncooperative target. A prospect is given towards the end of the paper with a preliminary design for a decision process for autonomy.

Simulation Environment for the Rendezvous Path and Abort Trajectory of ADReS-A

The threat of space debris to operational satellites is a growing concern for satellite op- erators. Large objects with high collision probability, e.g. rocket bodies and non-functional satellites on highly frequented orbits, form hereby the largest source for the debris’ increase in number. Various ideas on how to remove those objects have been proposed, always point- ing out, that the handling of an uncooperative target comes with many difficulties. Being in close vicinity, the spacecraft relies on its on-board sensors to calculate relative position and velocity. A flawless connection to ground control cannot be ensured and is, moreover, time consuming, which creates the need for high-level autonomy and on-board processing of the spacecraft. The idea of implementing autonomy in spacecraft in general has been followed for some time, however, requirements for a specific implementation need to be de- rived from a designated mission architecture. Therefore, this paper introduces the concept of ADReS-A, short for Autonomous Debris Removal Satellite #A, its mission architecture and a first approach of how to visualize the rendezvous path of the satellite and the abort in case of a failure. The simulation shall serve as a testbed for the coming autonomy and is based on the sensor data of ADReS-A, derived from the spacecraft preliminary design, also presented briefly within this work.

Mission Architecture for active Space Debris Removal using the Example of SL-8 Rocket Bodies

Space debris has become a serious problem for the safe operations of spacecraft in low Earth orbit. Attempts such as improving trajectory predictions of non-functional objects in space, guidelines for safer launches nowadays, and an implementation of post-mission disposal however will not stop the growth in debris numbers. One solution for mitigation is therefore the realization of removal missions.Due to space debris being an issue for all space faring nations, this paper introduces an exemplary removal mission for 5 Russian SL-8 rocket bodies at an inclination of 83∘ orbiting at an altitude of 970 km - an area crowded with space debris and thus involving a high collision risk.The mission draft presented is based on a main satellite (Autonomous Debris Removal Satellite - ADReS-A) and - according to the number of targets - 5 de-orbit kits. The idea presented includes a parking orbit close to the targets positions, into which the set-up is launched. While the kits are equipped with a de-orbit thruster, the task of ADReS-A is, to approach the uncooperative target, berth it, stabilize the compound system and attach the de-orbit kit onto the target. The main satellite will take each de-orbit kit separately to the individual targets, shuttling between the parking orbit and the target orbits.A prospect addressing the highly critical situations resulting from the interaction with an uncooperative target is given towards the end of the paper with a preliminary design for a decision process for autonomy.