Comparison of Crater Behavior of Water Ice by Low and High Density Projectiles under Hypervelocity Impact

Hypervelocity impact tests have been performed on water ice in the velocity range of 3 to 7 km/s, by using low and high density projectiles. The projectile materials included polycarbonate and stainless steel, with diameter of 1.0 mm. The ice targets were solid cylinders at 253K made from pure water. The crater morphology in the solid ice caused by different projectile and different velocity were observed. The crater sizes were measured and compared with previous tests impacted by aluminum projectiles. The results showed that: 1) the crater diameter and crater depth were dominated by different mechanisms, the crater depth was mainly caused by the projectile penetration, while the crater diameter was mainly caused by the ice spallation; 2) the crater depth showed stronger projectile density dependence than crater diameter, while the crater diameter by higher density projectile showed stronger velocity dependence than that by lower density projectile; 3) the crater volume scaled with the impact energy, the crater diameter by high density projectile showed 'energy scaling' behavior, while the crater diameter by lower density projectile showed 'momentum scaling' behavior.