地月转移自由返回轨道偏差传播分析

地月转移自由返回轨道的稳定性分析对载人登月任务轨道设计及中途修正策略规划有着重要意义。本文在地月会合坐标系下,推导了地月转移自由返回轨道的偏差传递方程,并基于标称轨道数据和解析方法,得到了轨道偏差随时间的扩散规律。研究结果表明:轨道偏差会随着时间推移逐渐增大,特别是在绕月飞行后,偏差量迅速增加,偏差累积将使飞行器无法返回地球。因此,工程实际中不存在严格意义上的自由返回轨道,飞行器在地月飞行过程中必须要进行中途修正。

Analysis of Deviation Propagation for Translunar Free Return Orbit

Stability analysis of translunar free return orbit is significant for manned lunar mission orbit design and midcourse correction strategy programming. In this paper, a deviation propagation equation for free return orbit is derived in the synodic coordinate system. Based on the nominal orbit data and analysis method, the propagation law of orbit deviation is obtained. The simulation result indicates that the orbit deviation increases with the increasing fly time, and the deviation increased more quickly after the spacecraft orbiting the moon so that it could not return to the Earth. So the strict free return orbit in engineering is not existed, and the midcourse correction in earth-moon transfer fly is necessary.