A numerical investigation on effectiveness of kinetic impact deflection of near-Earth asteroids with material point method

Near-Earth asteroids (NEAs) pose a potential threat to human life and property due to their risk of collision with Earth, making NEA defense a longstanding focus of research. Kinetic impact deflection, exemplified by NASA's DART mission, has emerged as a promising method, yet its effectiveness remains sensitive to material properties and impact parameters. This study employs the Material Point Method (MPM), an integrated Lagrangian-Eulerian computational framework capable of resolving large deformations and multi-phase flow, to numerically simulate the deflection efficiency of idealized asteroids under kinetic impacts. MPM models incorporate elastic-plastic material behavior and granular flow to capture large deformations and fragmentation processes, and characterize energy dissipation in porous and solid targets. MPM results align well with hypervelocity impact experiments for crater scaling laws, validating the approach. Parametric studies are then conducted to investigate the momentum transfer efficiency for different types of asteroids, varying a range of asteroid properties and impact conditions. The findings highlight MPM's capability in resolving complex fragmentation physics, providing actionable insights for optimizing impactor design in future planetary defense missions.