Projectile shape effects on shielding performance at 7 km/s and 11 km/s

NASA has developed enhanced performance shields to improve the protection of spacecraft from orbital debris and meteoroid impacts. One of these enhanced shields includes a blanket of Nextel(TM) ceramic fabric and Kevlar(TM) high strength fabric that is positioned midway between an aluminum bumper and the spacecraft pressure wall. As part of the evaluation of this new shielding technology, impact data above 10 km/sec have been obtained by NASA Johnson Space Center (JSC) from the Sandia National Laboratories HVL (''hypervelocity launcher'') and the Southwest Research Institute inhibited shaped charge launcher (ISCL). The HVL launches flyer-plates in the velocity range of 10 to 15 km/s while the ISCL launches hollow cylinders at similar to 11.5 km/s. The >10 km/s experiments are complemented by hydrocode analysis and light-gas gun testing at the JSC Hypervelocity Impact Test Facility (HIT-F) to assess the effects of projectile shape on shield performance. Results from the testing and analysis indicate that nonspherical shapes are more penetrating than equal mass spheres (by factors of 1.2 to similar to 2). Impact data also demonstrated the Nextel(TM)/Kevlar(TM) shield provides superior protection performance compared to an all-aluminum shield alternative.