砾石堆结构超高速撞击溅射物特性

Research on Characteristics of Hypervelocity Impact-Induced Ejecta in Rubble-Pile Targets

动能撞击偏转是小行星防御可实施性与成熟度较高的方案,且已在相关深空探测任务得到了应用。面向不同类型的小行星,如何在撞击过程中产生更大的动量传递并利用溅射物观测数据评估撞击效果是该技术待解决的关键问题。建立了不同粒径与质量占比的砾石堆靶体模型,开展了铝制撞击体超高速撞击砾石堆靶体的数值模拟研究,分析了砾石粒径与质量占比对撞击溅射物特性的影响规律与机制。结果显示:砾石堆结构在超高速撞击作用下,形成非对称形貌溅射物,且在砾石缝隙区域可形成射线形溅射物;射线部分溅射物具有更大的溅射角,射线长度、射线数量与砾石直径及其质量占比相关,针对建立的砾石堆靶体模型,大粒径砾石靶体产生的沿撞击速度反方向的溅射物动量最大,可为未来动能撞击任务的区域选取提供参考。

Kinetic impact deflection is a highly feasible and mature technique in the field of asteroid defense,and has been successfully implemented in related deep space exploration missions.However,a critical issue associated with this technology pertains to the optimization of momentum transfer during the impact process,as well as the evaluation of impact efficacy through analysis of ejecta observation data,for a diverse range of asteroid types.In this study,a target model composed of rubble-piles,constructed with varying proportions of boulder size and mass ratio,was developed and subsequently subjected to numerical simulations of hypervelocity impact of aluminum impactors.The impact of boulder size and mass proportion on the morphology of the ejecta was investigated,and the underlying mechanisms governing these effects were elucidated.The results of the investigation demonstrated that asymmetrical ejecta morphologies were produced as a result of the hypervelocity impact of aluminum impactors on rubble-pile targets,with ray-like ejecta emerging in the gaps between the boulders.The ray part of the ejecta has a larger eject angle,and the ray length and quantity are related to boulder diameter and mass ratio.Based on the rubble-pile target model established in this study,it was found that the maximum momentum of the ejecta produced in the opposite direction of the impact velocity was generated by large-diameter boulder targets.This paper can provide valuable reference for the selection of impact zones in future kinetic impact deflection missions.