Trajectory Optimization and Orbit Design of Spacecraft in Hovering Mission

Abstract

The typical hovering mission contains three stages: the orbit transfer from the original orbit to the hovering orbit; hovering in the orbit; and the orbit transfer returning to the original orbit. This paper provides an in-depth study for the hovering mission in two aspects: the trajectory optimization for orbit transfer and the orbit design for the hovering stage. Using the Gauss pseudospectral method, the trajectory optimization for the orbit transfer is transformed into the nonlinear programming problem. To solve the nonlinear programming problem, a calculation method combining interior-point method with sequence quadratic programming is proposed to guarantee convergence rate and computational efficiency. The position of the mission spacecraft is fixed relative to the target spacecraft in the spacecraft hovering stage. Aiming at the orbit design of the spacecraft hovering stage, the expression of the required control to maintain spacecraft hovering is deduced by taking advantage of the characteristic of the relatively static operation state of the mission spacecraft. The simulation results prove the validity of the Gauss pseudospectral method in trajectory optimization of the hovering mission, and provide the required control to maintain hovering for the mission spacecraft.