Dry mass optimization for the impulsive transfer trajectory of a near-Earth asteroid sample return mission

Asteroid sample return missions are an area of active research for deep space exploration. Trajectory optimization for near-Earth asteroid sample return missions with chemical propulsion is studied in this paper. In previous studies, minimizing the velocity increment was usually used as the optimization objective. This paper focuses on the optimization of the spacecraft dry mass, aiming to reasonably coordinate the lifting capability of the launch vehicle and the maneuvering capability of deep space probes. A multi-objective optimization model is proposed to find a Pareto-optimal solution for the maximization of the spacecraft dry mass and minimization of the transfer time, considering both impulsive maneuvers and gravity-assist maneuvers. Compared with the results of the previous optimization model to minimize the velocity increment, the simulation results show that solutions with a much higher spacecraft dry mass can be obtained, and hence, the group of feasible asteroid targets is enlarged. Multi-objective optimization of the spacecraft dry mass and transfer time can effectively redistribute the time for trajectory transfer and time available on asteroids, making mission design much more flexible.