Collision Risk Assessment and Mitigation Strategy for the GSOC GEO Satellites

Kurzfassung

The collision avoidance strategy for geostationary satellites is discussed in the paper. The possible encountering objects were first analyzed from the past events and also from the object population in the geostationary ring. Compared with the conjunctions in LEO, an in-track maneuver for the collision avoidance has to be planned more carefully, because the satellites have to be kept inside the control box. To mitigate the high collision risk while keeping the satellites inside the box, different maneuver strategies were analyzed. Depending on the avoidance maneuver size as well as the drift time, an appropriate E/W maneuver strategy had to be applied. Another strategy using the N/S maneuver allows performing larger thrusting without violating the control box; however the achieved separation varied according to the orbital plane angle and the close approach epoch. The strategies were finally applied to high risk conjunctions in the past. For all cases, the conjunctions could be mitigated and the control requirements were satisfied.