Mission planning of safe approach and emergency evacuation to large slow-rotating space debris

Abstract

• A dynamic safety corridor approach strategy is developed with approach window and straight path. • The safe approach trajectory is planned to optimize transfer time and fuel consumption. • An emergency evacuation strategy is designed and the safety velocity is analyzed. • Motion precision and convergence time are ensured based on coupling control of orbit and attitude. The on-orbit service technology is expected to play an important role in space debris removal missions. In order to capture and remove space debris objects, servicing satellites need to have the ability of mission planning, to quickly approach space debris objects in limited time, to avoid possible collisions and other safety issues, and to have the ability of emergency suspension and evacuation in the event of sudden accidents. The mission planning of safe approach and emergency evacuation to large slow-rotating space debris is studied in this paper. Firstly, the relative orbit and attitude dynamics model of servicing satellite and space debris object is established. Then, a dynamic safety corridor approach strategy is proposed according to the motion characteristics of large slow-rotating space debris and the optimal safe approach trajectory is planned based on particle swarm algorithm. For the purpose of instant response to the possible accidents during the approach, an emergency evacuation strategy is proposed, while the safety velocity and the emergency evacuation time are analyzed. The relative orbit and attitude coupled control method is designed based on global terminal sliding mode control. The stability of this control method is proved by Lyapunov argument as well as the error convergence time is analyzed. Finally, the effectiveness of the mission planning and control method is verified by numerical simulations. The results of this paper can provide a preliminary technical exploration for the approach and capture strategy of large slow-rotating space debris.