Spacecraft relative orbit finite-time control for proximity to non-cooperative target

The observer-based relative orbit finite-time control is investigated for rapid proximity to target spacecraft. A finite-time controller, based on non-singular terminal sliding mode technique, is firstly proposed to perform proximity maneuver, which can drive relative position and velocity to the expected value in finite time rather than in the asymptotie sense. In the consideration of escape maneuver of non-cooperative spacecraft, a finite-time observer is then proposed and included in the modified controller to deal with this problem. It should be noted that the acceleration of escape maneuver can be estimated in finite time, the globally finite-time convergence of closed-loop system is therefore guaranteed. Simulation results are finally provided and discussed to illustrate the performance of the proposed controllers.