Hydrocode modeling of advanced debris shield designs

Abstract

The NASA Johnson Space Center (JSC) Hypervelocity Impact Test Facility (HIT-F) has developed several low mass, high performance shielding concepts to protect spacecraft from orbital debris and meteoroid impact. Development testing requires shield concept validation in the impact velocity regime from <1 km/s to ∼14.5 km/s. Current two-stage light gas gun testing limits maximum impact velocities to 8 km/s; therefore, Sandia National Laboratories and Southwest Research Institute have developed advanced launchers capable of accelerating non-spherical shaped masses to ∼15 km/s. Since the shape of the impactor influences final rear wall damage, hydrocodes are employed to evaluate the so called shape effect at velocities greater than 8 km/s. A series of 14 hypervelocity impact simulations were conducted using the CTH hydrocode. Simulations modeled spherical aluminum (Al) and Al flat plate projectiles of various masses impacting double bumper all Al Whipple shields (DB). Experimental results at ∼7 km/s are compared with simulation and ballistic limit curves are constructed for the DB Whipple shield in the velocity regime greater than 7 km/s. Comments are also made on the shape effect mass ratio for spherical and flat plate projectiles.