B&P Project 25-3: Regolith Gas Permeability Tester Project (REGAPT2)

Regolith particles accelerated by gases from plume-surface interactions (PSI) during the
descent and landing of a lander vehicle on the Moon represent a potential risk to the sustainable human
exploration of the lunar surface. However, the nature of gas flow through granular materials also has broad implications across many fields. For example, gases escaping from the interior of comets permeate through regolith to create a coma around the nucleus and a tail of primordial dust; gas volatiles liberated from planetary surfaces for in situ resource utilization must diffuse through regolith; and gas has been used in touch-and-go sample acquisition maneuvers to excite asteroid regolith into collection pads. The permeability of regolith is additionally important when considering the construction of subterranean habitats. This FY25 Research and Technology (R&T) project at NASA KSC focused on measuring the gas permeability of granular lunar regolith simulant material in support of the Human Landing System (HLS) PSI project (see https://ntrs.nasa.gov/citations/20230018215). For each HLS PSI ground test case (or computational modeling of PSI effects), the gas permeability of lunar regolith is a fundamentally important parameter needed to understand the efficiency of gas flow in producing plume-surface interaction effects during a lunar landing.