Research Progress on impact ejecting behavior of granular targets

Impact ejecting, deemed a crucial constituent of the impact process, is recognized for its pivotal role in both engineering applications and scientific analyses within the domain of deep space exploration. Its importance is underscored across diverse activities, encompassing anchoring on small asteroid surfaces, impact sampling, kinetic impact deflection, and the evaluation of ejecta deposition on planetary surfaces. With small asteroids commonly featuring surfaces covered with regolith, granular targets are employed in laboratory settings to simulate and conduct research. This paper presents a comprehensive review of the research progress concerning the behavior of impact ejecting on granular targets. The formation process of impact ejecting and methods for describing ejecta curtains are expounded upon, while an analysis of the dimensional similarity laws governing impact ejecta, along with their applicability and limitations, is conducted. Additionally, the influence of factors such as target material parameters, impact conditions, target surface morphology, and impactor shape and structure on impact ejecta behavior is summarized. Finally, existing research challenges are objectively identified, and potential direction for further scientific inquiry into the behavior of impact ejecta on granular targets are proposed.