These snapshots were taken during testing at Rice University on October 7-8, 2002
Hypervelocity test gun. The gun uses hydrogen, compressed by a piston driven by a shotgun shell, to accelerate small particles to a velocity of 7 km/s.
The particle enters the evacuated target chamber through the hole just visible at the corner of the target (upper left). The target is the micrometeoroid shield, with a plastic scintillator and phototube behind it to simulate the orbital condition.
Close-up of damage to the shield caused by a 2.2 mm aluminum ball. The layers have been folded back to show the interface between the outer layers (ceramic fabric separated by foam) and the backing layers (Kevlar). In the distance of 20 mm from the point of impact, the shield has dispersed the energy of the projectile into an area approximately 30 mm in diameter. The Kevlar stopped the debris (in this case).
Close-up of damage to the scintillator wrapping caused by debris penetrating the shield (a thinner shield than in the photo to the left). The hole is 8 mm in diameter, smaller than the hole within the shield, but large enough to alow light to reach the scintillator. If this happens in orbit, the ACD tile will be disabled.