Reachability-Driven Reference Governor for Hybrid-Actuated Spacecraft Attitude Control

This paper proposes a reachability-driven reference governor for hybrid-actuated spacecraft attitude control during docking. Actuator saturation and partial loss of effectiveness reduce the feasible torque set, which may render the desired attitude temporarily unreachable. Local and finite-horizon reachability are evaluated to determine whether the system can directly track the commanded target. When reachability is lost, the governor replaces the target with a feasible subgoal on the boundary of the reachable domain. Preliminary six-degree-of-freedom simulations show that the proposed method maintains stable attitude behavior under actuator degradation and provides an effective alternative to fault-detection-based switching strategies.