Information-Based Guidance and Control Architecture for Multi-Spacecraft On-Orbit Inspection

Abstract

Inspection or mapping of a target spacecraft in a low Earth orbit using multiple observer spacecraft in stable passive relative orbits (PROs) is a key enabling technology for future space missions. Our guidance and control architecture uses an information gain approach to directly consider the tradeoff between gathered data and fuel/energy cost. The architecture has four components: information estimation, spacecraft’s absolute and relative state estimation, motion planning for relative orbit initialization and reconfiguration, and relative orbit control. The information estimation quantifies the information gain during inspection of a spacecraft, given past and potential future poses of all spacecraft. The estimated information gain is a crucial input to the motion planner, which computes PROs and reconfiguration strategies for each observer to maximize the information gain from distributed observations of the target spacecraft. The resulting motion trajectories jointly consider observational coverage of the target spacecraft and fuel/energy cost. For the PRO trajectories, a fuel-optimal attitude trajectory that minimizes rest-to-rest energy for each observer to inspect the target spacecraft is designed. The validation on a mission simulation to visually inspect the target spacecraft and on a three-degree-of-freedom robotic spacecraft dynamics simulator testbed demonstrates the effectiveness and versatility of our approach.