Collision Avoidance Operations for LEO Satellites Controlled by GSOC

Abstract

The German Space Operations Center (GSOC) is currently building up an operational proximity monitoring and mitigation system. Proximity events are detected based on the “Two-line Elements” (TLEs) and precise orbit information from locally operated missions. Despite evident deficiencies in the quality and timeliness of the available orbit information, TLEs are currently the only source of orbit information for the numerous space objects. Therefore, the TLE uncertainty needs to be carefully assessed for the collision risk estimation. Even after a realistic error analysis, the orbit information of a possible encountering object has to be refined for a proper planning and implementation of collision avoidance maneuvers. For this purpose, the use of radar tracking is currently planned, for which an accuracy assessment is to be considered. In this paper, the collision avoidance procedure at GSOC is first presented. The orbit accuracy and its improvement by a radar tracking are then discussed, followed by a presentation of their application to the operational collision avoidance process.