NASA selected GIMLI to investigate Marius Hills Pit

In a September 30, 2026, announcement, NASA said it had selected GIMLI, a Planetary Science Institute (PSI)-led lunar investigation, through its PRISM program. The project is designed to investigate whether Marius Hills Pit opens into a subsurface void or lava tube, while also studying the pit’s formation and the Moon’s volcanic history.

NASA selected the PSI-led investigation through PRISM

GIMLI stands for Geophysical Instruments for Marius Lunar pit Investigation. NASA selected the project through its Payloads and Research Investigations on the Surface of the Moon (PRISM) program. Its target, Marius Hills Pit, lies in a volcanically diverse region of the Moon.

The selection announcement made GIMLI a planned surface investigation of a specific lunar feature. Its central scientific question is whether an underground void extends from the pit—not a result the project has already reported.

The possible underground connection is the research question

GIMLI will investigate whether the pit opens into a lava tube or another subsurface void. The project combines several kinds of geophysical measurements to study what lies beneath the lunar surface.

Nathaniel Putzig, GIMLI’s principal investigator, has described the planned approach as combining active-source seismic methods with ground-penetrating radar and gravity measurements to improve understanding of subsurface properties.

The planned instruments will study the pit and its surroundings

GIMLI’s proposed instruments include ground-penetrating radar, seismic sensors, a gravimeter and cameras. The cameras are intended to image the lunar surface and the pit’s exposed walls; the geophysical instruments are part of the investigation of the ground below.

The search for a possible cave is only one part of the project’s scientific purpose. GIMLI also aims to investigate how Marius Hills Pit formed and what it can reveal about lunar volcanism, even if the measurements do not identify a cave.

PSI leads the project; NASA plans delivery through CLPS

NASA says the payload is planned to reach the lunar surface through its Commercial Lunar Payload Services (CLPS) initiative. PSI identifies Honeybee Robotics as a commercial partner that will manage the project, build specified instruments, help integrate equipment with the lander and rover, and help lead surface operations with PSI. The Norwegian Space Agency is to provide the ground-penetrating radar.