星历模型下地月自由返回全飞行过程轨道设计

Aiming at the need of manned lunar landing missions, the trajectory design problem of Earth-Moon transfer with free return capability under the ephemeris model is studied. The three-dimensional Earth-Moon free return trajectory is solved under the three-body model, by which the distribution of free return trajectories in the eislunar space is obtained. Under the assumption of two-body model, the three-pulse maneuvers strategy near the Moon is proposed. Furthermore, a two-step optimization correction method is proposed, during which the orbital altitude and reentry corridor are respectively considered as the main constraints. The interior-point method and SQP algorithm are used to optimize and correct the initial states of free return trajectory under the ephemeris model. Then, the lunar three-pulse maneuvers are optimized and corrected by SQP algorithm, and then the entire Earth-Moon transfer trajectory consisting of free return segment and lunar three-pulse maneuvers segment are obtained. The simulation results have verified the feasibility of the proposed method.