201 The G.K. Gilbert Award Session: Geology of Mars, Mercury, Asteroids, and Icy Satellites in Honor of Scott Murchie

This session honors our 2025 Gilbert awardee Dr. Scott Murchie and highlights the broad impact of the fields of research with which he has been involved, focusing on the composition, spectroscopy, and geomorphology of planetary bodies throughout the solar system.

Tuesday, 21 October 2025
1:30 PM - 5:30 PM
HBGCC, 214C

Impact Experiments to Investigate Impact Cratering Processes in Ice-Bearing Targets

Paper number: 201-5
Program: Technical Sessions
Time: 2:30 PM – 2:45 PM

Authors

Abstract

The lunar poles are high-priority targets for future human and robotic exploration. Furthermore, in the proposed Moon-to-Mars Architecture, Martian regions hosting volatiles may also be targets for exploration. Like the rest of the lunar surface, polar terrains are extensively impact cratered. However, unlike other areas of the Moon, the poles are thought to contain significant amounts of subsurface water ice mixed with the lunar regolith, based on previous studies. The effects of this icy component are currently poorly understood. To accurately interpret the lunar polar cratering record for scientific, exploration, and resource utilization purposes, this knowledge gap must be addressed. Here, we report on a series of hypervelocity impact experiments designed to reveal how silicate-ice mixtures behave during impact, which we conducted at the NASA Ames Vertical Gun Range.

During our experimental campaign in 2024 and 2025, we systematically varied the ratio of particulate ice to silicate regolith simulant to examine how changes in ice fraction affect cratering outcomes. For the silicate component, we used three different materials: the LHS-1E regolith simulant, powdered pumice, and #20-30 quartz sand. The typical impact speed was 5 km/s. We employed a suite of diagnostic tools to collect data before, during, and after the experiments, including thermocouple gauges, high-speed cameras, ejecta catchers, line lasers, a thermal camera, a 3D scanner, and still photography.

Most experiments were performed with the target at subzero temperatures, with the coldest experiments approaching -60 degrees Celsius in the target material at the time of impact. We had to overcome several technical barriers to do experiments at these low temperatures because our particulate targets were several times larger than the solid targets used in prior studies.

Initial assessments indicate that the crater depth-diameter ratio may depend on target temperature and that the icy component does not experience preferential excavation over the silicate component. Further analysis will assess changes in crater morphology and morphometry as a function of target properties, examine ejecta texture, and undertake 3D reconstruction of the ejecta curtain. All data will be archived to enable future studies of this extensive dataset.

This work was supported by NASA through the RASSLE SSERVI node, under contract number 80NSSC24M0016. CHvdB was also supported by DLR project 50OW2402.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413167

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