A GNC simulation of a far range approach towards a target in geostationary orbit

Abstract

This paper describes a GNC simulation as part of a feasibility analysis conducted by DLR/GSOC for future on-orbit servicing missions in near-geostationary orbit. The simulation addresses a far-range approach from several kilometers down to a few hundred meters, which includes relative orbit determination based on simulated optical measurements, and autonomous maneuver planning for relative trajectory control. One hundred simulation runs are performed with varying initial conditions based on the expected absolute orbit determination errors prior to the approach initiation. The safety of the formation is granted, as the servicer satellite never enters a pre-defined collision-avoidance area around the target spacecraft. The results of the simulation show that a low-cost far range approach based on optical measurements is feasible up to a safe transition to a mid-range sensor. The results of the paper as well as the proposed GNC algorithm itself can find applications in future on-orbit servicing missions in near-geostationary orbit.