Asteroid Hypervelocity Collisions and Defenses

To address the challenges of complex asteroid geometries, low modeling efficiency, and unclear momentum transfer mechanisms during hypervelocity collisions, this study developed a voxelization modeling method accelerated by a Bounding Volume Hierarchy（BVH） structure. Key momentum transfer laws under hypervelocity impact were computationally analyzed using the Smoothed Particle Hydrodynamics（SPH） method. The results demonstrate that compared to GPU-based voxelization methods, the present approach achieves an 86.8% efficiency gain in voxelization processing, with 96.5% voxel identification accuracy and particle mass errors below 3.5%. A strong correlation exists between impact angle and the momentum transfer factor（β）, peaking at β = 3.82 for a 60° impact—representing a 41.7% increase over the 30° impact case. Ejecta-induced recoil contributes 68.3% of the total momentum change imparted to the asteroid. This study confirms that the BVH-accelerated voxelization method efficiently handles concave geometries（7.3 times faster than conventional methods） and identifies 60° as the optimal impact angle for maximizing momentum transfer efficiency in rubble-pile asteroids（β > 3.5）. The established technical framework is scalable to kilometer-scale celestial body deflection scenarios, providing critical tool support for optimizing multi-impactor collaborative trajectories.