Dome Pressurization and Regolith Porosity

Long term settlement of lunar or Mars caves or subsurface features on planetary bodies where large pit openings exist provide an opportunity to substantially increase livable volume areas and allow inhabitants freedom from confines of living in modules or enclosed in a cave environment. Various studies centered on enclosing a lunar skylight pit with a pressurized dome are under investigation by the authors. An intuitive approach of merely placing a dome cap over the skylight pit is fraught with a number of issues. Accomplishing this in a practical fashion without having the seal independent of the regolith surface is a challenge for understanding the porosity of the lunar regolith along the pit walls and outer rim of the pit. Not least among these issues is prevention of the regolith from consuming too much gas and never reaching an equilibrium pressure. Essentially, what happens to gas pumped into the dome? How much of it will simply pass into the surrounding desiccated regolith? How much of this valuable atmospheric resource will simply diffuse away into the skylight walls? Lunar regolith porosity studies investigate various challenges associated with pressurizing a large porous geologic feature.