Optimal Control of Gravity-Tractor Spacecraft for Asteroid Deflection

摘要

Near-Earth objects can pose amajor threat to Earth.New ideas and concepts are continually proposed tomitigaternpossible impact. Among them, the gravity tractor is promising and has been the focus of many recent studies onrnasteroid deflection. The gravity-tractor concept is studied and trajectories are designed to lessen the risk of impact ofrna near-Earth object. By means of a mathematical model of the gravity tractor, a high-fidelity trajectory designrnmethod for deflection is proposed. The optimal deflection of an asteroid is computed by an indirect method, and therntrajectory of the spacecraft is deduced by an inversion of dynamics and optimal control.When the deflection achievedrnis compared with results published to date, the better performance of the deflection is clear. This paper shows thatrncurrent literature analyses of the gravity-tractor designmay be nonoptimal because the assumption made about therncontrol penalizes the concept. The use of optimal control actually improves the robustness of the designed trajectoryrnwhile obtaining higher deflection.