火星引力捕获动力学与动态误差分析

火星探测的制动捕获机会唯一,是影响任务成败的关键. 从限制性三体问题出发,推导了火星引力球、作用球与希尔球半径的计算公式,比较了三者的特点与适用范围,并结合作用球的定义与物理意义,给出了一种火星探测制动捕获段的工程定义. 在作用球范围内建立了火星制动捕获段动力学模型,给出了对捕获轨道精度产生影响的各项误差源. 通过蒙特卡洛仿真,定量分析了导航初始误差、发动机推力误差、制动点火时间误差等对捕获轨道近火点与远火点高度的影响,并对不同误差源可能导致的超差概率进行了分析,指出了影响捕获精度的主导误差源,可为我国未来火星探测制动捕获段的任务实施提供参考. 

MARS GRAVITY CAPTURE DYNAMIC MODEL AND ERROR ANALYSIS

Mars orbit capture is a one and only opportunity for Mars probes and the key factor to determine whether the mission is successful. Starting with the constrained three-body problem, equations for calculating the Mars gravity sphere, influence sphere and Hill sphere are derived. Their property and applicability are discussed. Based on the definition and physical significance of influence sphere, an engineering definition of capture phase is proposed. The orbital dynamic model was built inside the influence sphere and the error sources that may affect the accuracy of capture orbit are presented. Finally, the influences on perigee and apogee of the capture orbit caused by the position and velocity navigation error, engine thrust error and timing errors are analyzed through Monte Carlo simulations. The limit exceed possibility caused by different error sources are also discussed and the dominating sources is pointed out. The result can be used as a reference for the orbit capture implementation of future Chinese Mars orbiters.