NASA has selected the GIMLI project to study the Marius Hills pit on the Moon. The goal is to determine whether this depression opens into an extensive underground lava tube or cave.
The project Geophysical Instruments for Marius Lunar pit Investigation is led by the Planetary Science Institute (PSI). The principal investigator is senior scientist and PSI deputy director Than Putzig. The partner is Honeybee Robotics, which will build a significant portion of the equipment.
The instruments will be delivered to the Moon using a commercial lander and rover under the CLPS program. Once there, they will carry out comprehensive measurements directly from the surface.
GIMLI's arsenal includes ground-penetrating radar, seismic sensors, a gravimeter and cameras. Together they will make it possible to peer beneath the lunar soil and, if a cavity is found, to estimate its dimensions.
Particularly noteworthy is the active seismic sounding. This will be the first deliberate generation of seismic waves on the Moon since the Apollo 17 mission in 1972.
The Marius Hills pit is located in one of the most volcanically diverse regions of the Moon. Orbital observations have long pointed to possible lava tubes beneath the satellite's surface.
Such natural cavities could become reliable shelter for future astronauts. They would protect against radiation, sharp temperature swings and micrometeoroids — without the need to deliver heavy shielding from Earth.
Scientists emphasize that confirming the existence of an extensive cave would provide not only practical benefits for future missions but also new data on the Moon's volcanic history. How far does this possible cavity extend, and what will it reveal about the satellite's past?
The project was selected under the PRISM program. NASA announced it in early October 2026. The study will be one of the first direct geophysical soundings of lunar pits from the surface.
