地月系L1点的月球借力间接转移轨道设计

针对地月系L1点（LL1）的轨道转移问题,在平面圆型限制性三体问题模型下,提出了利用月球借力的间接转移设计方法.转移设计分为地月转移轨道段和月球至LL1流形段.首先,通过改变LL1点初始机动速度,逆向积分LL1点的拟流形,以寻找初始速度、月心会合坐标系下的轨道高度和相位角这三者之间的关系,确定月球—LL1流形段微分改正的初始条件.然后,借助地月系不同转移时间的霍曼转移轨道所对应的近月点高度和相位角的关系,获得使2段转移在近月点相拼接的地月转移轨道段.这种设计方法给出了一系列LL1点间接转移轨道,将此设计结果与其他文献中的转移设计方法进行比较,此间接转移轨道比低能量转移轨道节省时间,比直接转移轨道节约能量.

Indirect Transfer to the Earth-Moon L1 Point via Lunar Flyby

A lunar flyby is used to design a three-impulse indirect transfer to L1 point （LL1） of the earth-moon system with moderate transfer time and energy in the context of the planar circular restricted three-body problem.The design process is comprised of two segments,i.e.,the earth-moon transfer phase and the moon-LL1 transfer phase.First,the pseudo-manifold of the LL1 point is integrated backward to study the relationship among the perilune velocities,heights and phase angles of the trajectories in the synodic coordinates by changing the maneuver velocity at the LL1 point.Second,different earth-moon transfer trajectories corresponding to different flight time are calculated to obtain their perilune velocities,heights and phase angles.The two segments that intersect at the perilune are chosen and the total energy budgets are calculated.A series of transfer trajectories are obtained in this way and the results are compared with those in previous literature.The indirect transfer is time-saving in comparison with low energy transfer and it costs less energy than direct transfer.