PRESSURE AND GRAVITY EFFECTS ON THE SIMULATION OF METEORITE IMPACT CRATERS.

Meteorite impact craters were simulated by detonation of chemical explosives in a cohesionless medium at various air pressures 0.0005 mm Hg to 1000 mm Hg and at four gravity conditions 0.17 g, 0.38 g, 1.0 g, and 2.5 g. Crater parameters diameter and depth were measured to determine the effects of pressure and gravity on the cratering process. Lip height was measured only in the pressure work. Diameter and depth increased approximately 12 and 10 respectively with decreasing pressure while lip height remained relatively constant. Crater diameter decreased from a mean value of 47.9 cm at 0.17 g to 33.7 cm at 2.5 g. Depth did not vary appreciably from 1.0 g to 2.5 g 7.7 cm to 5.7 cm. A scaling equation was derived to relate crater diameter, pressure, gravity, and energy in a cohesionless medium within the pressure range of 300 mm Hg to 1000 mm Hg and the gravity range of 0.17 g to 2.5 g. To obtain additional information on the mechanics of crater formation, craters were formed in mediums with horizontal layering. Scouring and compaction were found to be predominant processes in both the pressure and gravity phases. Author