Receding-Horizon Trajectory Planning Algorithm for Passively Safe On-Orbit Inspection Missions

Abstract

This paper presents a sampling-based receding-horizon inspection algorithm that allows observation of a tumbling target vehicle while guaranteeing an arbitrary low risk of collision between the chaser performing the inspection and the target. The proposed algorithm relies on a simple heuristic search of the best inspection trajectory, and it can be suited to both onboard implementation as an autonomous guidance module and offline trajectory design. The main strength of the algorithm resides in its ability to quickly solve black-box optimal control problems, exploiting an input sampling approach that is commonly used in robotic motion planning. A new and computationally simple method to verify the safety of the two vehicles is also presented and implemented into the algorithm. The proposed method allows taking into account relative navigation and maneuver execution errors, as well as the effects of unmodeled perturbations. The results obtained with the algorithm are compared to the ones obtained with a classic inspection strategy making use of inclined football orbits. It is shown that the proposed guidance algorithm consistently ensures the completion of the inspection mission, and it takes advantage of the characteristics of the natural dynamics of the relative motion to outperform the classic approach.