Low-Velocity Impact Experiments in Low-Duration Microgravity

Recreating environmental conditions (i.e., low-ambient pressure and low-gravity) found on small bodies is essential for the study of the dusty regolith that covers the surface of asteroids, comets, and other planetary satellites. Here we present the results of experiments designed to study the physics of regolith response to low-velocity impacts, which are relevant whether we are attempting to understand the origins of our solar system or working toward exploration activities. In our previous experiments, we have utilized various flight campaigns including shuttle missions, parabolic flights, and suborbital rockets; however, these types of experiment campaigns are expensive and difficult to repeat. To make these experiments more accessible, we utilize a laboratory drop tower (~11ft. tall producing ~.8s of freefall) and designed an experiment chamber to reproduce experiment campaigns similar to those we have flown. Impactors are propelled into a bed of regolith (lunar soil simulant JSC-1, or sieved quartz sand) in the evacuated experiment chambers. We control launch velocities (between ~30 - ~120 cm/s) and impactor energies (between ~2.1 - ~22.1 kJ) using springs and impactors of various masses. Impacts are observed using a high-resolution camera at 500 fps. We track impactor and regolith ejecta motion using manual and automated techniques to obtain values for impact velocities, impact energies, ejecta velocities and trajectories, ejecta mass limits, and coefficients of restitution.