Numerical Simulations of Laboratory-Scale, Hypervelocity-Impact Experiments for Asteroid-Deflection Code Validation

Asteroids and comets have the potential to impact Earth and cause damage at the local to global scale. Deflection or disruption of a potentially hazardous object could prevent future Earth impacts, but due to our limited ability to perform experiments directly on asteroids, our understanding of the process relies upon large-scale hydrodynamic simulations. Related simulations must be vetted through code validation by benchmarking against relevant laboratory-scale hypervelocity-impact experiments. To this end, we compare simulation results from Spheral, an Adaptive Smoothed-Particle Hydrodynamics (ASPH) code, to the fragment-mass and velocity data from the 1991 two-stage light gas-gun impact experiment on a basalt sphere target, conducted at Kyoto University by Nakamura and Fujiwara. We find that the simulations are sensitive to the selected strain models, strength models and material parameters. We find that, by using appropriate choices for these models in conjunction with well-constrained material parame...