Why is NASA probing the Marius Hills Pit on the Moon?

The Marius Hills Pit is a roughly 65-by-90-meter hole in an ancient volcanic region of the Moon that may open into a subsurface lava tube. NASA selected the GIMLI instrument suite under its PRISM program to send ground-penetrating radar, seismic sensors, a gravimeter, and cameras there on a commercial lunar lander and rover. The goal is to test whether a large underground void extends from the pit; if it does, such a lava tube could offer future astronauts natural shelter from radiation, extreme temperatures, and micrometeoroids.

Source: Planetary Science Institute — PSI-led team selected for NASA PRISM program to explore potential lunar cave

Image: Marius Hills Pit — possible lava tube skylight. NASA/GSFC/Arizona State University, public domain.