大气-弹道捕获式火星探测器的轨道构建与优化方法研究

Mars exploration is becoming the key direction of China’s deep space activities. A huge amount of propellant mass is necessary to perform the convenient Mars capture process and in particular to break the spacecraft upon Mars arrival that may appear single-point failures. This method also delimits the insertion window. This proposal suggests an “aero-ballistic capture” (ABC) that properly patches ballistic capture and aerobraking methods, which is expected to satisfy the requirements of less fuel consumption, low hazard of failure, and flexible capture window. The spacecraft is assumed to be a “box-wing” configuration and the orbital dynamics involving multi-body gravities and the usable atmosphere is established for propagations. The construction of ABC orbits is studied, as well as the solution space. Then, the Δv-leveraging effect within the regions of weak stability boundaries is analyzed. A hierarchical optimization strategy, including the fuel consumption and the total flight time, is proposed to assess the performance of the obtained orbits. The yawing angle is used to freely adjust the orbital inclination during the aerobraking phase, in order to decrease the correction maneuvers. An analytical method is investigated to derive the yawed angle with respect to a minimum flight time. The ABC orbit is expected to provide theoretical results and judicious options for the future probes upon Mars and other planets or natural satellites.

火星探测是我国未来深空探测活动的重点方向。传统的火星捕获采用近火点冲量制动方式入轨，燃料消耗多，单点任务失败风险高且对地球发射和火星捕获窗口约束严格。本项目通过弹道捕获和大气制动的有机结合和无缝拼接，提出“大气-弹道捕获”方式来兼顾燃耗、风险和窗口三方面的要求。首先建立“盒-翼”构型探测器的轨道动力学模型，重点研究大气-弹道捕获轨道的构建方法及相应的解空间分布，通过分析弱稳定边界区域的Δv杠杆效应，得到以燃料消耗为主、飞行时间为辅的分层优化策略，提出利用姿态偏航角修正轨道倾角的方案进一步降低捕获燃耗，并借助解析推导确定时间最优偏航角。该捕获方式有望为未来火星或其他天体探测捕获任务轨道设计提供新的理论依据和技术支撑。

本项目针对“盒-翼”探测器提出了一种利用大气制动模式辅助弹道捕获的低燃耗入轨方式，设计了一套将大气制动与弹道捕获相结合的方法，提出了基于脉冲修正和姿态偏航角的两种轨道倾角调整策略，并解析推导了最优偏航角的选取方法；将所提方法应用于火星捕获任务、小行星采样返回任务和地球—金星探测任务。仿真结果表明：大气制动与弹道捕获相结合的入轨方式能够大幅降低将探测器捕获到目标天体绕飞轨道的燃耗。考虑到大气制动方式时间过长，本项目又针对飞船式探测器提出了一种利用大气捕获模式辅助弹道捕获的低燃耗入轨方式，设计了一套将大气捕获与弹道捕获相结合的方法，提出了一种半解析的近拱点动压快速计算方法。仿真结果表明：该入轨方式不仅能够大幅降低单次大气穿越的热压峰值，减轻热防护系统质量，而且能够规避传统大气捕获的“单点任务失败”风险。本项目拓展了弹道捕获的应用，将其与大气制动/大气捕获/大气进入相结合，实现了以较低燃耗将探测器捕获到大椭圆弱稳定轨道或任务圆轨道，可为我国未来开展的深空探测任务提供理论支持。