Analysis of the impactor simulation modeling on the dynamic response of kinetic impact for asteroid defense

Due to the limitations of simulation scale and computational time on resolution, simplified impactor models used in current kinetic impact defense simulations for asteroids often fail to accurately reproduce the complex impact responses caused by the internal structure of the real impactor. In order to investigate the influence of different impactor simulation modeling approaches on the impact response in kinetic impact defense for asteroids, a systematic comparison was conducted using the three-dimensional SPH method. The results show that different impactor modeling approaches can have a significant influence on the simulation results, with each simplified model failing to fully replicate the impact response of the real impactor. Compared to the real impactor, the momentum enhancement factor for solid aluminum spheres and low bulk density aluminum spheres is 10 % to 50 % higher. In terms of the ejection cone angle, the results for low solid density aluminum spheres tend to be larger than those for the real impactor, with the differences being more pronounced at early stages. In the study of the distribution of the azimuthal angle of the ejection momentum, the results for aluminum cubes with 90 % porosity are typically closer to those of the real impactor than those for aluminum cubes with 63 % porosity. However, the extremely high porosity also causes deviations in the ejected momentum distribution in scenarios of complete asteroid damage, differing from the real impactor. Therefore, when focusing on specific impact response results, simplified models with minimal errors can be selected. Among these, aluminum materials with 63 % or higher porosity offer the best overall performance as simplified impactor models, followed by low solid density aluminum materials. These findings provide experimental evidence for optimizing impactor modeling selection and clarify the applicable scenarios and limitations of different modeling approaches.