Initial Approach Segment Control for Out-of-Plane Capture Based on a Space Tether System

Study of the release of a tether from a base station spacecraft to a given rendezvous maneuver feasibility point for the out-of-plane capture of space debris by a space tether system. Considering the out-of-plane angle of the system, the pseudospectral method is used to plan the optimal trajectory of the initial approach section, and the effect of the initial state error on the initial approach segment trajectory is analyzed. In turn, the system model is controlled by segmental feedback using sliding mode control based on an adaptive convergence law to overcome the initial state error. The results show that initial approach section control can be achieved by adjusting the tether tension and the out-of-plane thrust on the capture mechanism, provided that the relevant constraints are met.