University of Kentucky
Studies in Engineering and Physics: Study 1: The Physical State of Lunar Soil in the Permanently Shadowed Craters of the Moon
Institution
University of Kentucky
Faculty Advisor/ Mentor
Philip Metzger; Alan Male
Abstract
The physical state of the lunar soil in the permanently shadowed craters of the moon is inferred from experimental investigation. The surface density of lunar soil is predicted to significantly affect the erosion rate under a rocket exhaust plume due to the interaction of particle forces. The surface density of the regolith in these craters may be significantly less compacted when compared with unshadowed areas of the moon. The theory behind that statement deals with the thermal cycling of granular materials (which is known to be a very efficient compactor of soil). The angle of the sun on these craters prohibits any light (and thus heat) from entering. As a result the lunar regolith particles in the craters do not undergo the extreme temperature cycles that are experienced by the regolith in the other areas of the moon. With this said, the permanently shadowed craters of the moon must be studied because future missions plan to land in or around these craters. It is vital to know the density of the regolith in these regions so excavating, roving, and landing interactions, along with the energy budgets and employment schedules for related technology, can be scaled and calculated properly. Soil compaction was tested as a function of depth for the two main forces of compaction on the lunar surface: thermal cycling and vibration (moonquakes). As a result of this study is it now understood that the change in relative density due to thermal cycling lunar simulant JSC-1A is a function of depth. In addition, the relative density as a result of vibrational compaction is a function of amplitude, but normally not a function of depth.
Studies in Engineering and Physics: Study 1: The Physical State of Lunar Soil in the Permanently Shadowed Craters of the Moon
The physical state of the lunar soil in the permanently shadowed craters of the moon is inferred from experimental investigation. The surface density of lunar soil is predicted to significantly affect the erosion rate under a rocket exhaust plume due to the interaction of particle forces. The surface density of the regolith in these craters may be significantly less compacted when compared with unshadowed areas of the moon. The theory behind that statement deals with the thermal cycling of granular materials (which is known to be a very efficient compactor of soil). The angle of the sun on these craters prohibits any light (and thus heat) from entering. As a result the lunar regolith particles in the craters do not undergo the extreme temperature cycles that are experienced by the regolith in the other areas of the moon. With this said, the permanently shadowed craters of the moon must be studied because future missions plan to land in or around these craters. It is vital to know the density of the regolith in these regions so excavating, roving, and landing interactions, along with the energy budgets and employment schedules for related technology, can be scaled and calculated properly. Soil compaction was tested as a function of depth for the two main forces of compaction on the lunar surface: thermal cycling and vibration (moonquakes). As a result of this study is it now understood that the change in relative density due to thermal cycling lunar simulant JSC-1A is a function of depth. In addition, the relative density as a result of vibrational compaction is a function of amplitude, but normally not a function of depth.