地月自由返回轨道设计

摘要

载人月球探测任务需要着重考虑任务的安全性,能否"自由返回"是很重要的一项指标.在轨道设计上存在两项要求,首先是地月转移,然后是经月球近旁转向并判断能否返回地球,即实现飞越月球以后的无动力返回.文章结合精确的行星历表(DE405),首先比较不同力模型中同一条轨道的返回情况,以确定初始轨道设计过程中需要考虑的摄动力;然后分析了返回时近地距的各种影响因素,包括出发时刻、转移时间、倾角组合等,提出了一种可使返回近地距逐渐向设定的目标值靠拢的单向搜索方法,该方法简单易行,可信度高,能够满足轨道设计时要求的各项约束条件.该工作对中国将要进行的载人月球探测任务中需要用到的自由返回轨道的设计具有一定的参考价值.%The most important thing in manned lunar explorations is safety, whether the probe can free return when facing power failure at the perilune is an important criterion. With the aim of designing cislunar free return trajectory, two requirements should be satisfied,the first is transfer trajectory design between the earth and moon,the second is whether the probe can fly back after lunar swing-by.Combined with the precise astronomical ephemeris (DE405),one trajectory in different mechanical models was compared in order to determine what perturbations should be considered in the preliminary trajectory design.Then, almost all factors (departure time, transfer time, inclination angles combination, etc.) affecting the return perigee distance of the probe was analyzed.A unidirectional search method was proposed,which could make the probe's return perigee distance tend to the set target value gradually. The method is simple and reliable, and it can satisfy all the requirements of initial trajectory design. The work is of some value to the cislunar free return trajectory design of our manned lunar explorations in the near future.