Revealing the impact of operational constraints on aerodynamic collision avoidance maneuvers: In-flight results from the BEESAT-4 CubeSat

Abstract

Effective collision avoidance strategies will play a central role in the future in order to take account of the rapidly increasing number of satellites in Low Earth Orbit and the associated increase in collision probabilities. For small, lightweight satellites (e.g. CubeSats), propellantless options represent a highly attractive solution. A targeted change in the satellite’s ballistic coefficient alters the drag experienced and thus provides a way to actively adjust the satellite’s trajectory, e.g. to avoid an imminent collision. Despite extensive theoretical progress in this field, no in-orbit demonstrations of propellantless collision avoidance have been carried out to date. Thus, there exists a lack of experience on how potential operational limitations affect the theoretical considerations. To bridge the gap, a collaborative effort between the Julius-Maximilian Universität Würzburg, the Technische Universität Berlin, and the Universität Stuttgart has been initiated. This article presents the results of a joint study utilizing BEESAT-4, a conventional 1U CubeSat operated by the Technische Universität Berlin and launched into a 500 km Sun-synchronous orbit in June 2016. The study investigates how operational constraints impact the feasibility of maneuver sequences. To achieve this research objective, the impact of operational constraints on the effectiveness of orbital drag manipulation was evaluated. The analysis reveals that a consideration of the operational constraints reduces the maneuver effectiveness of an aerodynamically controlled collision avoidance maneuver for the BEESAT-4 satellite by almost 90 %. The reduction is revealed via theoretical considerations as well as an analysis of the in-orbit flight data conducted by OKAPI:Orbits GmbH. Overall, the findings are intended to enhance the practical deployment of sophisticated aerodynamic maneuvers in orbit, benefiting both the academic community and broader aerospace applications.