HYPERVELOCITY IMPACT TESTS AND SIMULATIONS OF SINGLE WHIPPLE BUMPER SHIELD CONCEPTS AT 10-KM/S

A series of experiments has been performed to evaluate the effectiveness of a Whipple bumper shield to orbital space debris at impact velocities of approximately 10 km/s. Upon impact by a 19 mm (0.87 mm thick, L/D approximately 0.5) flier plate, the thin aluminum bumper shield disintegrates into a debris cloud. The debris cloud front propagates axially at velocities of approximately 14 km/s and expands radially at a velocity of approximately 7 km/s. Subsequent loading by the debris on a 3.2 mm thick aluminum substructure placed 1 14 mm from the bumper penetrates the substructure completely. However, when the diameter of the flier plate is reduced to 12.7 mm, the substructure, although damaged, is not perforated. Numerical simulations performed using the multi-dimensional hydrodynamics code CTH also predict complete perforation of the substructure by the subsequent debris cloud for the larger flier plate. The numerical simulation for a 12.7 mm flier plate, however, shows a strong dependence on assumed impact geometry, i. e., a spherical projectile impact geometry does not result in perforation of the substructure by the debris cloud, while the flat plate impact geometry results in perforation.