Abstract: For the problem of noncooperative spacecraft approach, flyingaround and obstacle avoidance in unmanned onorbit service, the relative kinematical and dynamic model of orbit and attitude in the noncooperative spacecraft feature part body coordinate are established. The trajectory planning is carried out, with the objective function of optimal time and fuel, and the constraint of dynamics and path. The continuous optimal control problem is discretized by the Gauss Pseudospectral method. Then the optimal path is obtained by solving the transformed nonlinear programming problem. The sixdegreeoffreedom coordinated position and attitude trajectory tracking error model are established, and the trajectory tracking control law is designed. The results of the closedloop simulation show the effectiveness and stability of the control law.

Key words: noncooperative spacecraft, approach, flyingaround, Gauss Pseudospectral method, trajectory planning, trajectory tracking