Looking at lunar lava tubes as possible living quarters
The Moon is not a habitable environment. Nor are volcanoes. Put them together though, and you might have an attractive bit of real estate for potential Moon colonies. The trick is to find places where the volcanic activity has actually died down, and then move into the resulting caverns lava leaves behind. On Earth, these lava tubes offer information about lava flows, plus a chance for some sight-seeing. On the Moon, they may be key locations safer than anywhere on the satellite’s surface.
As lava flows away from a volcano or other fissure in the Earth’s crust, it often branches out into various streams, like tendrils of very hot, sludgy water. Those streams can become lumped together, cohering into a single, thicker flow, but wrapped in an accumulation of cooler, solidifying rock. The result is a very lumpy, curdled-looking surface of hardened rock around a buried shaft of flowing lava. Occasionally, “skylights” will open to the surface, which vent gasses and heat, but also help keep pressure from building up underground. If an obstruction doesn’t block things up too much, these flows can actually allow all the molten material to pass by, leaving an empty, cave-like shaft behind. If no volcanic activity is present, lava tubes can be stable enough to enter and explore.
Skylights in space
The GRAIL spacecraft surveying the Moon has found some evidence of lunar lava tubes. As seen in photos of the Moon’s surface, the telltale signs are areas where a an empty channel has collapsed in a sort of wormy shape, as well as old skylights revealing deep pits likely connected to empty cave networks. Aside from the indication of the Moon’s geologic past, these lava tubes may be big enough for astronauts to one day call home.
Based on this early evidence and our understanding of the Moon’s composition and gravity, there’s a good chance lunar lava tubes can be much bigger than anything found on Earth. Scientists have calculated that there’s a good chance we could someday find stable lava tubes three miles wide and 2 miles tall, making them big enough to house a city. If confirmed, this would be an attractive location for a future colony, because the rock at the top of the lava tube could make up for the lack of atmosphere and magnetic field on the Moon, shielding people and buildings from the Sun’s radiation and asteroid impacts that could easily pose a threat to anyone living there. With similar skylights having been seen on Mars, these geological shelters could, at the very least, act as early staging areas for astronauts until more permanent structures can be developed.
Source: Lunar Shelter: Moon Caves Could Protect Astronauts by Nola Taylor Redd, Space.com