Chance-Constrained Autonomous Spacecraft Formation Reconfiguration and Rendezvous with Passive Abort Safety

Abstract

This paper addresses fuel-efficient maneuver planning under uncertainty for spacecraft relative motion in low-Earth orbits with passive safety using relative orbital elements (ROE) framework. We adopt a chance-constrained optimal control formulation that explicitly incorporates operational uncertainty in the planning process and directly controls the state distribution. Motivated by the critical importance of collision safety in proximity operations, passive safety is guaranteed probabilistically by enforcing safe free-drift behavior under total loss of control. We derive two passive-safety chance constraints formulations based on keep-out-zone definitions that leverage geometry insights into relative motion provided from ROEs. This gives alternative formulations for different proximity operations scenarios under uncertainty. State-triggered-constraint logic is also developed to combine these passive-safety formulations and expand applicability. In addition, we apply iteratively reweighted [Formula: see text] minimization to promote minimal control intervention while maintaining passive safety under uncertainty. The resulting nonconvex optimal control problems are solved using sequential convex programming. Monte Carlo simulations of representative scenarios under uncertainty validate the proposed formulations with the intended risk level and achieve efficient performance by minimizing [Formula: see text].