NASA has selected a new scientific project called GIMLI to investigate a mysterious 34-to-45-meter deep pit on the Moon to determine if it opens into a massive underground lava tube. Researchers hope the mission will discover whether these ancient volcanic cavities can serve as natural radiation and temperature shelters for future astronaut crews.
NASA Selects GIMLI to Probe Marius Hills Pit
The target site is the Marius Hills Pit, situated within the Oceanus Procellarum region on the Moon's Earth-facing side. Japanese lunar orbiter Kaguya first spotted the feature in 2009. Scientists suspect the opening functions as a natural skylight into an extensive subsurface conduit. This exploration effort aims to verify if the cavity connects to a large subterranean tunnel system.
Volcanic activity formed these structural features between 3.8 billion and 3.0 billion years ago. As molten basalt flowed across the terrain, outer layers cooled and solidified while hot material continued rushing underneath. The drainage of that internal lava left behind hollow conduits that may remain intact today. Researchers plan to use a specialized payload package to pierce the subsurface and measure what lies beneath the volcanic floor.
Ground-Penetrating Radar and Seismic Equipment
To inspect the hidden geology, the GIMLI mission will deploy a suite of active instruments directly onto the lunar terrain. The payload includes a ground-penetrating radar provided by the Norwegian Space Agency, alongside seismic sensors and a gravimeter. Honeybee Robotics, a company linked to Blue Origin, is building a significant portion of this diagnostic hardware.
Putzig explained that combining active-source seismics with radar and gravity measurements will reveal detailed properties of the shallow subsurface. Gareth Morgan, deputy principal investigator for the project, noted that confirming a large-scale lava tube will clarify how lunar volcanism operated during the satellite’s formation. Even if an enormous cavern is absent, the collected data will expose buried regolith layers and ancient lava flows normally hidden from view.
Shielding Astronauts From Extreme Environments
Verifying a subterranean chamber carries immense practical value for crewed exploration programs. Lunar surface conditions present severe hazards, including harsh temperature swings, radiation, and frequent micrometeoroid impacts. Natural rock overhangs and basalt tubes could block these environmental dangers. Nicky Fox, associate administrator of the Science Mission Directorate at NASA, stated that projects selected under the PRISM initiative provide essential safety data and survival guidance for upcoming Artemis missions.
Additional investigations accompanying this landing include LEMS-SP, which monitors micrometeoroid strikes and volatile gases, and DISCO, which performs measurements of the surface. Commercial Lunar Payload Services landers will transport these scientific packages to the lunar surface ahead of scheduled human arrivals. Engineers will utilize the findings to determine whether subterranean spaces can safely house long-term base camps.
