考虑星历的火卫一邻近区域限制性多体问题建模与分析

MODELING AND ANALYSIS OF RESTRICTED N-BODY PROBLEM WITH EPHEMERIS IN VICINITY OF PHOBOS

火星及其天然卫星火卫一在深空探测领域的重要性日渐显现.由于火星强烈的三体引力摄动,传统二体问题下的受摄开普勒轨道在火卫一的邻近区域无法存在,研究探测器在火卫一邻近区域的轨道运动时,需要建立限制性多体问题模型.为提高现有轨道模型精度,在火卫一本体系建立了一种考虑星历的限制性多体动力学模型.该模型考虑的因素有:考虑真实星历、真实姿态运动与多面体引力势的火卫一引力;考虑J2项的火星三体引力摄动;太阳,地球及木星的三体引力摄动.在保留上述高精度模型主要特征的基础上,为减小数值仿真计算量,对该模型进行简化,提出了考虑火卫一简谐天平动和球谐引力势的椭圆型限制性三体问题模型.在两种模型和现有动力学模型中,对准卫星轨道进行仿真,分析了轨道的形状和星下点轨迹,证实了本文提出的两种模型在轨道设计中的必要性.

Mars and its natural moon,Phobos,are of great significance for deep space explorations.The N-Body Prob⁃lem is necessary for the design of orbits around Phobos,since the traditional perturbed Keplerian orbit is proved to be impossible in the vicinity of Phobos.A restricted N-Body Problem model with the ephemeris of celestial bodies is estab⁃lished in Phobos’body-fixed reference frame.The influencing factors considered in this model include:the polyhedron gravity field of Phobos with the real attitude libration;Mars attractive force with J2;gravitational perturbations of Sun,Jupiter and Earth.This model is further simplified according to its characteristics with an elliptical restricted three-body problem model considering Phobos’approximated harmonic libration and gravity harmonics being established.Orbits are simulated with different models with the trajectories and ground tracks being depicted.Comparisons are made among simplified models and the high-fidelity model to confirm the necessity of the proposed models.