Experimental comparison of Al sphere hypervelocity impact on Al-foam sandwiched shield and Al-foam stuffed shield

Hypervelocity impacts on spacecraft in low earth orbit by meteoroids and space debris poses a threat to space missions, and the use of a shield can significantly decrease the probability of a catastrophic failure. Aluminum foam is a new type of material for shield of spacecrafts for it bears favorable characteristics when subjected to hypervelocity impact of space debris. An Al-foam Sandwiched Shield and an Al-foam Stuffed Shield were presented under the concept of light-weight shield structure and their shield performances were compared through hypervelocity impact experiments using two-stage light gas gun. The base materials of the open-cell foam used were Al-Si alloy ZL102 and pure aluminum respectively. The total bumper areal density, rear wall excluded, was about 0.8g/cm² for most shields tested. The projectile launched was 2017 aluminum sphere with its diameter fixed to be 3.97mm and the impact velocity was between 2.6-6.3km/s with a 0 degree incident angle. The damages of the bumpers included and the rear wall were examined thoroughly after impact and compared to each other to evaluate the shield performance of different configurations and the influence of different base materials as well. The experimental results indicated that within the speed range tested, the Al-foam Stuffed Shield has significantly better performance than the Al-foam Sandwiched Shield. And for a same shield configuration, the base material of Al-Si alloy used can provide slightly better performance than that of pure aluminum.