On October 5, 2026, NASA selected the Geophysical Instruments for Marius Lunar pit Investigation (GIMLI) project through its Payloads and Research Investigations on the Surface of the Moon (PRISM) programme. Led by Planetary Science Institute senior scientist Than Putzig, GIMLI will investigate the Marius Hill Pit, an approximately 34-meter-deep opening measuring 65 by 90 meters in the volcanically diverse Marius Hills region, to determine whether it connects to a large underground cave or lava tube.
GIMLI will combine ground-penetrating radar, seismic sensors, gravity measurements, and cameras aimed at the surface and exposed pit walls. A confirmed void could provide natural protection from lunar radiation, micrometeoroids, and severe surface temperature fluctuations, reducing shielding mass, power demand, and exposure risk for long-duration habitation and preserved biological, cultural, and industrial assets.
The Ark team should track GIMLI's deployment schedule, instrument data, detected void geometry, access constraints, structural stability, and environmental conditions. Ark site-selection models should treat the Marius Hills Pit as a high-priority candidate while requiring follow-on measurements of radiation dose, regolith properties, volatile availability, seismic hazard, communications, logistics, and construction feasibility before committing critical archives.