火卫一周期准卫星轨道及入轨分析

围绕火卫一的准卫星轨道（QSOs）因其具有良好的稳定性，是火卫一探测任务最为实用的轨道。在平面圆型限制性三体问题模型下，利用庞加莱截面和KAM环迭代方法探究了准卫星轨道的周期轨道族，并给出不同能量准卫星周期轨道的初始条件。针对火卫一周期准卫星轨道入轨，提出一种转移轨道设计方法:对准卫星周期轨道调整速度后进行反向积分，直至离开火卫一邻近区域，从而得到由火星环绕轨道向火卫一周期准卫星轨道的转移轨道，并调整转移轨道参数对燃料与时间消耗进行优化。研究结果表明，当周期准卫星轨道能量处于特定区间时，存在特定速度脉冲区间，可利用火卫一引力实现较少燃料消耗的轨道转移；在该速度脉冲区间中，通过选取较小的速度脉冲，可缩短转移时间。 

Periodic quasi-satellite orbits around Phobos and their injections

The Quasi-Satellite Orbits (QSOs) around Phobos are the most practical orbits in Phobos exploration missions due to their stability. With the planar circular restricted three-body problem model, Poincaré's surface of section and KAM tori iterations are employed to investigate the periodic QSOs. Initial conditions of periodic QSOs with different energy are determined. A method to design transfer orbits from orbits around the Mars to periodic QSOs is proposed, which propagates orbits backward from injection points on QSOs with a ΔV to somewhere away from Phobos to complete a transfer. The fuel consumption and transfer time are optimized by changing transfer parameters. It is found that when the energy of the periodic quasi-satellite orbit is in a specific interval, a specific interval of impulsive velocity exists, in which the Phobos' gravity can be used for fuel saving, and a shorter transfer time can be achieved with a small impulsive velocity.