通过动能撞击潜在威胁小行星以使其轨道偏转,是目前而言技术成熟度最高且也是未来最为可行的行星防御方案之一。分析确定对小行星的最优撞击位置和撞击方位,以最大化轨道偏转效果,对于动能撞击防御方案的设计具有重要意义。论文以偏转Apophis小行星为例,给出一种最优撞击方案的初步设计方法。首先,根据小行星和地球的轨道交会几何关系,分析确定动能撞击的轨道偏转目标;随后,将小行星受动能撞击简化为航天器的脉冲推力变轨,利用二体轨道理论,推导得到在预定偏转目标下,撞击器对小行星的最优撞击位置和撞击方位;最后,建立小行星受摄运动的数值轨道预报模型,对最优撞击方案下小行星的实际轨道偏转量进行评估验证。结果表明,该撞击方案的轨道偏转效果与实际情况基本吻合,证明所提的优化方法对于精细化的撞击防御方案设计具有一定参考价值。
Deflecting the orbit of a potentially hazard asteroid by kinetic impact is currently the most technically feasible defense concept.Finding the optimal interception orbit of the impactor to the asteroid so as to achieve the maximum orbit deflection under a given fuel consumption,is of great significance to the design of the defense scenario.This paper takes the kinetic impact on the Apophis asteroid as an example,a method to design the optimal interception trajectory of the impactor is proposed and illustrated.Firstly,the orbit deflection of the asteroid caused by impact is regarded as an impulse maneuver,and the motion of the asteroid is simplified into a two-body problem.Then,the optimal interception position and interception orientation of the impactor on the asteroid is determined using classical theories of orbital dynamics and control,which maximizes the orbit deflection of the asteroid for a given fuel consumption.Finally,a numerical orbit prediction model for Apophis is established,which is used to evaluate the actual orbit deflection of the optimal impact solution.The results show that orbit deflection given by optimal impact solution is basically consistent with the actual situation,which proves that the optimization method has a certain reference value for the design of elaborate impact schemes.
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