星历模型下地月自由返回全飞行过程轨道设计

面向载人登月任务需要，针对星历模型下具备自由返回能力的地月转移轨道设计问题进行了研究。在三体模型下对地月三维自由返回轨道进行了求解，得到了地月空间内的自由返回轨道分布情况。在二体模型假设下对近月段的三脉冲变轨进行了求解，给出了变平面机动的计算方法。进一步提出了两轮逐次优化修正策略，分别以高度和再入走廊为主要约束，采用内点法和SQP算法在高精度星历模型下对自由返回轨道初值进行逐次优化修正。之后，采用SQP算法在星历模型下对近月三脉冲变轨进行优化修正，得到了星历模型下的自由返回+近月三脉冲变轨地月转移策略。仿真校验结果表明本文提出的方法能够在给定约束下有效求解星历模型下具备自由返回能力的地月转移轨道，为载人登月任务的转移轨道设计提供参考。

Design of Earth Moon Free Return Transfer Trajectory under Ephemeris Model during the Entire Flight Process

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 cislunar 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.