火星探测转移轨道初始设计与分析

Transfer orbit initial design and analysis for Mars exploration mission

根据推进方式和是否采用金星借力,火星转移轨道分为大推力直接转移轨道、大推力金星借力转移轨道、小推力直接转移轨道和小推力金星借力转移轨道4类。传统的轨道设计方法只是针对某一类特定的转移方案进行轨道优化,而并未针对不同的转移方案进行详细对比分析。文章以2020/2022年发射窗口为例,针对4类基本火星转移轨道进行研究。首先,基于不同轨道初始设计方法,对4类轨道进行了初始设计,得到了每类转移方案的能量最优转移轨道。然后,基于设计结果和能耗对4类转移方案进行了横向对比分析,得到了不同策略下的转移轨道的特性。基于小推力的火星探测任务轨道对发射能量要求低;大推力直接转移和借力金星的发射窗口交替分布,可以互为备份;基于小推力推进的探测器采用金星借力转移策略相比直接转移能够减少10%的能耗,优势十分明显。

According to the propulsion mode and whether to use Venus gravity-assist,Mars transfer orbit is divided into four types：the impulse direct transfer orbit,the impulse Venus′gravity-assist transfer orbit,the low-thrust direct transfer orbit,and the low-thrustVenus′ gravity-assist transfer orbit.In order to comprehensively analyze the orbit characteristics of the four Mars transfer strategies,the energy optimal transfer orbits for every transfer orbit strategy respectively were designed. In addition,the orbital characteristics of different Mars transfer strategies were obtained by numerical simulation and computation.The beneficial conclusions were drawn based on the comparative analysis of the simulation results.The low-thrust Mars transfer trajectory design is not restricted by launch windows.The launch windows open alternately for impulse direct transfer and impulse Venus′gravity-assist transfer.The energy consumption of low-thrust probe, which adopts Venus′gravity-assist transfer strategy,is reduced by 10% compared with direct transfer.The effect of Venus gravity assist transfer in energy consumption is very obvious.