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

Abstract

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.

Key words： asteroid defense; rubble-pile structure; hypervelocity impact; impact-induced ejecta

References

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