Passively Safe Receding Horizon Control for Satellite Proximity Operations

Recent on-orbit mission performance illustrates a pressing need to develop passively safe formation flight trajectories and controllers for multiple satellite proximity operations. A Receding Horizon Control (RHC) approach is formulated that directly relates navigation uncertainty and process noise to non-convex quadratic constraints, which enforce passive safety in the presence of a large class of navigation or propulsion system failures. Several Keplerian simulations are executed to examine increased Delta v usage incurred by adding passive safety constraints, the corresponding reduction in collision probability, and resulting passively safe formation flight geometries. Results show that modest cross-track motion significantly reduces collision probability, and that once a passively safe relative orbit is achieved, steady-state Delta v usage rates are comparable to usage rates without passive safety constraints. Navigation uncertainty and process noise are found to be significant Delta v usage drivers for passively safe proximity operations. On-orbit autonomous RHC control with passive safety constraints applied to proximity operation missions enables trajectory generation and control that reduces collision probability to acceptable levels while minimizing Delta v usage.