NASA announced on October 1, 2026, that it has selected three new scientific payload suites under its PRISM (Payloads and Research Investigations on the Surface of the Moon) program — and the standout is a mission that will hunt for a hidden lunar lava tube beneath the Marius Hills Pit, in what will be the first intentional seismic survey of the Moon's surface since the Apollo 17 astronauts detonated explosives there in December 1972.
What GIMLI Will Do at the Marius Hills Pit
GIMLI — the Geophysical Investigation for Mapping Lunar Interior — is led by Dr. Nathaniel Putzig of the Planetary Science Institute (PSI) in Tucson, with Honeybee Robotics (acquired by Blue Origin in 2022) building most of the hardware and the Norwegian Space Agency supplying radar expertise. The roughly 65-meter-wide (213-foot-wide) pit, first spotted by Japan's Kaguya orbiter around 2009, may be a skylight opening onto a vast underground lava tube.
The payload combines four instruments into the most direct surface-based investigation of any lunar pit ever attempted:
- Ground-penetrating radar — contributed by the Norwegian Space Agency — to read reflections from subsurface voids at far closer range than any orbital instrument.
- Active-source seismic system — hardware built by Honeybee Robotics — to generate seismic waves and measure how they travel through different materials. There has been no intentional generation of seismic waves on the lunar surface since Apollo 17 astronauts set out explosive charges in December 1972.
- A gravimeter to detect minute gravitational dips caused by underground voids — a surface echo of how NASA's GRAIL mission identified a candidate lava tube at Marius Hills from orbit a decade ago.
- Cameras to capture the exposed lava-flow layers of the pit walls at high resolution.
"It's long been a desire of mine to reintroduce intentional active-source seismic methods to planetary science, as it has essentially not been done since the Apollo astronauts conducted the first seismic surveys on the Moon," Putzig said.
Why Lunar Lava Tubes Could Become Astronaut Shelters
The Moon's surface is brutally inhospitable: solar and galactic radiation is unshielded, micrometeoroids bombard it continuously, and temperatures swing between roughly −173°C (−279°F) at night and 127°C (261°F) in daylight — a range of more than 250°C. A confirmed lava tube could provide all of that protection for free, without requiring shielding to be launched from Earth.
Lava tubes form when the crust of a flowing lava stream hardens while molten rock keeps moving beneath; when the eruption ends, the liquid drains, leaving a hollow tunnel. On the Moon — with gravity one-sixth of Earth's and the flood-basalt eruptions that built the lunar maria — studies suggest tubes more than 1 kilometer (0.6 miles) wide could have remained stable for billions of years, with theoretical cross-sections exceeding 1 billion cubic meters. A 2017 study combining Kaguya radar and GRAIL gravity data gave the strongest orbital evidence yet of a large stable void beneath the Marius Hills Pit; GIMLI would be the first attempt to confirm it from the surface.
"Such a cave may one day provide a safe haven for astronauts to escape the radiation and extreme temperature swings present at the Moon's surface," NASA stated alongside the selection announcement.
Two More Missions Join the Moon Base Science Push
GIMLI is one of three new PRISM payload suites announced together, all feeding NASA's Moon Base program and all to be delivered through the agency's Commercial Lunar Payload Services (CLPS) initiative:
- DISCO (Depth Imager with Spectral and Color Optics), led by Dr. Ariel Deutsch of NASA's Ames Research Center, will search for water ice in micro-cold traps near the lunar South Pole and study how rocket-plume landings disturb the surface.
- LEMS-SP (Lunar Environment Monitoring Station–South Pole), led by Dr. Mehdi Benna of the University of Maryland, Baltimore County, will operate as an autonomous, long-term station tracking seismic activity, micrometeoroid impacts, and volatile compounds — the hazard baseline engineers need before permanent hardware goes in.
"These PRISM selections will directly help NASA minimize risks to our astronauts while maximizing our agency goals as we set up humanity's first lunar outpost in preparation for sending the first astronauts to Mars," said Nicky Fox, NASA's associate administrator for the Science Mission Directorate.
There is no confirmed launch date yet — CLPS scheduling is finalized closer to flight — but with the selection complete, hardware development and mission planning can formally begin.
Watch: NASA Moon Base: The First Six Months — NASA's official video update on the Moon Base program, the lunar outpost effort that the new GIMLI lava-tube hunt is being built to support.