Numerical Simulations of Laboratory-Scale, Hypervelocity-Impact
Experiments for Asteroid-Deflection Code Validation
Abstract
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 parameters, the
simulations closely resemble with the experimental results. Numerical
codes implementing these model and parameter selections may provide new
insight into the formation of asteroid families (Michel et al., 2015)
and predictions of deflection for the Double Asteroid Redirection (DART)
mission (Stickle et al., 2017).