Three-Dimensional Crater Formation Measurements During Plume-Surface Interaction in a Reduced Gravity Environment

Abstract

Plume-surface interaction experiments were conducted in a 4.27 m tall drop tower facility to achieve 0g conditions, where g is Earth gravity at 9.81 m/s^2. Following the drop tower experiments, Martian (0.38g) and Lunar (0.16g) gravity conditions were simulated via parabolic flight. A stereo photogrammetry technique was used to capture crater formation under these gravity conditions, allowing for the quantification of the effect of gravity on crater depth and volume evolution. Three nozzle heights of 25D, 40D, and 50D, where D is the nozzle exit diameter, and three nozzle pressures of 5, 10, and 15 psig were investigated using the drop tower at both 0g and 1g. Results from the 0g experiments were compared to the results obtained using the same nozzle heights and pressures under 1g. The results indicated that crater evolution occurred more rapidly during 0g conditions, resulting in deeper and wider craters compared to those formed under 1g. During the parabolic flight, five nozzle heights between 25D and 60D at 15 psig were tested. It was found that the trend of more rapid crater evolution with decreasing gravity followed for Lunar and Martian gravity.