Trajectory Design and Control for Missed-Thrust Rendezvous

Safe and reliable spacecraft rendezvous maneuvers are crucial for numerous space missions. However, missed-thrust events (MTEs), characterized by a sudden loss of thrust, present significant challenges that can jeopardize mission success. In this research, rendezvous strategies are designed to mitigate the impact of MTE on spacecraft equipped with electric propulsion. A resilient trajectory shaping and control methodology is developed to mitigate the effect of thrust failures. The new approach introduces a missed-thrust sensitivity grade to generate trajectories with reduced sensitivity to MTE, incorporating a finite-horizon linear quadratic regulator and zero-effort miss/zero-effort velocity guidance, together with an optimization of the final time. The MTE-resilient rendezvous is designed while accounting for a realistic thruster operation mode, including conversion from continuous to pulsed commands. The results indicate that the proposed methodology significantly enhances the resilience of rendezvous maneuvers to MTE. Rendezvous plans designed using the MTSG approach demonstrate improved performance, with reduced variations in miss distances and miss velocities, as well as minimized variations in maneuver timing and approach direction, both in low Earth orbits and geostationary orbits.