Simulating hypervelocity impacts into rubble pile structures for planetary defense

Kinetic impactors are one of the most mature technologies for planetary defense and this technique was tested for the first time by NASA's Double Asteroid Redirection Test (DART) mission. The material and physical properties of the asteroid are very important in understanding the efficacy of a kinetic impactor. To constrain how the local topography of an impactor alters the response to the hypervelocity impact of a kinetic impactor, we used the adaptive smoothed particle hydrodynamics code, Spheral++, to impact plates into a rubble pile asteroid. By varying both the impact location and the strength between the boulders and regolith of the formed asteroid, we find that variations in the rubble pile contributes approximately 10% uncertainty to the resulting momentum enhancement in regolith dominated impacts. We further demonstrate that the craters produced from the impacts into the rubble pile are wide, shallow, and show deviations from symmetry due to the presence of boulders on the surface near the impact site. These simulations help us constrain the potential outcomes that may occur from a hypervelocity kinetic impact in a planetary defense scenario.