According to the new observations from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft, there are over 200 lunar pits that could provide shelter to the future astronauts.
The pits range in size from about 5 meters across to more than 900 meters in diameter, and three of them were first identified using images from the Japanese Kaguya spacecraft. Hundreds more were found using a new computer algorithm that automatically scanned thousands of high-resolution images of the lunar surface from LRO's Narrow Angle Camera (NAC).
Robert Wagner, Arizona State University, said that pits would be useful in a support role for human activity on the lunar surface as a habitat placed in a pit ideally several dozen meters back under an overhang would provide a very safe location for astronauts: no radiation, no micrometeorites, possibly very little dust, and no wild day-night temperature swings.
Most pits were found either in large craters with impact melt ponds, areas of lava that formed from the heat of the impact and later solidified, or in the lunar maria, dark areas on the moon that are extensive solidified lava flows hundreds of miles across.
There are almost certainly more pits out there, given that LRO has only imaged about 40 percent of the moon with appropriate lighting for the automated pit searching program, according to Wagner. He expects there might be at least two to three more mare pits and several dozen to over a hundred more impact melt pits, not including any pits that likely exist in already-imaged areas, but are too small to conclusively identify even with the NAC's resolution.
Wagner further explained that the ideal follow-up would be to drop probes into one or two of these pits, and get a really good look at what's down there, however, Pits, by their nature, cannot be explored very well from orbit, but even a few pictures from ground-level would answer a lot of the outstanding questions about the nature of the voids that the pits collapsed into, so they are currently in the very early design phases of a mission concept to do exactly this, exploring one of the largest mare pits.