Aas 15-116 a Sampling-based Approach to Spacecraft Autonomous Maneuvering with Safety Specifications

This paper presents a method for safe spacecraft autonomous maneuvering that leverages robotic motion planning techniques to spacecraft control. Specifically, the scenario we consider is an in-plane rendezvous of a chaser spacecraft in proximity to a target spacecraft at the origin of the Clohessy-Wiltshire-Hill frame. The trajectory for the chaser spacecraft is generated in a receding-horizon fashion by executing a sampling-based robotic motion planning algorithm named Fast Marching Trees (FMT∗), which efficiently grows a tree of trajectories over a set of probabilistically-drawn samples in the state space. To enforce safety, the tree is only grown over actively safe samples, from which there exists a one-burn collision avoidance maneuver that circularizes the spacecraft orbit along a collision-free coasting arc and that can be executed under potential thruster failures. The overall approach establishes a provably-correct framework for the systematic encoding of safety specifications into the spacecraft trajectory generation process and appears promising for real-time implementation on orbit. Simulation results are presented for a two-fault tolerant spacecraft during autonomous approach to a single client in Low Earth Orbit.