{"id":804051,"date":"2026-10-16T12:44:31","date_gmt":"2026-10-16T17:44:31","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=804051"},"modified":"2026-10-16T12:44:31","modified_gmt":"2026-10-16T17:44:31","slug":"caves-on-the-moon-are-target-of-new-nasa-mission","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=804051","title":{"rendered":"Caves on the moon are target of new NASA mission"},"content":{"rendered":"
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NASA wants to search for caves on the moon.<\/strong> How will it search? And where?<\/li>\n
A new mission named GIMLI<\/strong> will land and examine a volcanic pit \u2014 the Marius Hills Pit \u2014 in Oceanus Procellarum. It\u2019s one of 300 such pits known on the moon.<\/li>\n
GIMLI will use radar and other instruments<\/strong> to probe beneath the surface, looking for evidence of a lava tube-type cave.<\/li>\n<\/ul>\n
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Searching for caves on the moon<\/h3>\n
Are there caves on the moon? We don\u2019t know for sure yet, but evidence has been growing that they\u2019re there. <\/p>\n
Now, NASA has announced a new mission to search for moon caves. It\u2019s called GIMLI for Geophysical Instruments for Marius Lunar pit Investigation. The plan is to land the mission at the volcanic Marius Hills Pit in Oceanus Procellarum (\u201cOcean of Storms\u201d<\/em>), a vast, dark lava plain or lunar <\/strong>mare<\/em> (\u201csea\u201d) located on the western edge of the moon\u2019s near side.<\/p>\n
NASA announced it had selected the new mission on September 30, 2026. Brooks Mendenhall\u00a0described it in Astronomy<\/em> magazine on October 9. An official targeted launch or arrival date for the GIMLI payload hasn\u2019t yet been announced. <\/p>\n
Fun fact: the mission is named after J.R.R. Tolkien\u2019s cave-loving dwarf Gimli in The Lord of the Rings<\/em>!<\/p>\n
The Marius Hills Pit is \u2014 often called the Marius Hills \u201chole\u201d \u2014 is a steep-sided circular opening located within the Marius Hills volcanic region. GIMLI will peer down into the pit to see if it opens into a lava tube-type cave below the lunar surface. The pit is about 90 meters (295 feet) across. It\u2019s approximately 50 meters (164 feet) deep.<\/p>\n
And it could be a skylight, an opening in the roof of a lava tube, scientists believe.<\/p>\n
On Earth, lava tubes form when the outer layer of a lava flow cools down while molten rock keeps moving beneath it. Later, the lava flow eventually stops. Then, when the lava drains away, it leaves behind a hollow channel or tunnel.<\/p>\n
The mission was selected as part of the Payloads and Research Investigations on the Surface of the Moon (PRISM) program.<\/p>\n\n
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“The Gimli of Tolkien lore discovered a sprawling cave system which he described to his elven companion as, ‘chamber after chamber, Legolas; hall opening out of hall, dome after dome, stair beyond stair.'” Fingers crossed we don’t find any orcs on the Moon!buff.ly\/wT9bQNP<\/p>\n
\u2014 Planetary Science Institute (@psi.edu) 2026-10-15T17:30:37.529Z<\/p><\/blockquote>\n<\/div>\n<\/figure>\n
Science first<\/h3>\n
It will be exciting to see GIMLI land and to watch as it starts peering down into the pit. But the science will come first, according to Nicky Fox, associate administrator of NASA\u2019s Science Mission Directorate. She said:<\/p>\n
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NASA Science is building the ultimate interplanetary survival guide to ensure that science goes first to the lunar surface to provide our future astronaut crews with the vital information, resources and safety precautions needed ahead of time to survive the night on the moon.<\/p>\n<\/blockquote>\n
\nView larger. | Here are 3 different lunar pits. Because they are openings and not just shallow pits, scientists say that pits on the moon could lead to caves or lava tubes where temperatures might be comfortable for future human explorers to live and work. Image via NASA\/ GSFC\/ Arizona State University\/ Lunar Reconnaissance Orbiter Camera.<\/figcaption><\/figure>\n<\/div>\n
How GIMLI will search for caves on the moon<\/h3>\n
GIMLI won\u2019t enter the pit itself. Instead, it\u2019ll use a suite of instruments to scan below the surface.<\/p>\n
For example, it\u2019ll use the Norwegian Space Agency\u2019s ground-penetrating radar. Plus, a gravimeter \u2014 a specialized scientific instrument used to measure local variations in a gravitational field \u2014 will help look for places in the pit where empty lava chambers might exist. And seismic sensors will measure sound waves moving through the ground. And there will be cameras, too, of course.<\/p>\n
Notably, this kind of subsurface scanning hasn\u2019t been done on the lunar surface in decades. GIMLI\u2019s principal investigator Than Putzig at the Planetary Science Institute said it:<\/p>\n
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\u2026 has essentially not been done since the Apollo astronauts.<\/p>\n
That\u2019s a long time, since the 1970s.<\/p>\n<\/blockquote>\n
\nView larger. | The temperatures in the shaded area of this pit in the Mare Tranquillitatis region hold steady at around 63 degrees Fahrenheit (17 degrees Celsius). Scientists said the pit likely leads to a similarly temperate lava cave. That\u2019s one reason scientists think moon caves could be an option for future habitation for human explorers. Image via NASA\/ GSFC\/ Arizona State University\/ UCLA.<\/figcaption><\/figure>\n<\/div>\n
Why confirming a lava tube would be exciting<\/h3>\n
There are two reasons why confirming a lava tune on the moon would be exciting and important. Most intriguingly, it could offer protection to future astronauts. It could help shield them from the dangers of radiation from the sun, micro-meteoroids and extreme temperatures.<\/p>\n
And for scientists the planned GIMLI mission is an unprecedented opportunity to study a lava tube somewhere other than Earth. Scientists believe this moon cave would record the history of past volcanic activity on the moon. As Gareth Morgan at the Planetary Science Institute explained:<\/p>\n
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Confirming a substantial lava tube would give us an insight into how volcanism operated on the moon. Lava tubes are a common feature of basaltic volcanism on Earth, so identifying them on the moon means we could use knowledge of such terrestrial caves to better understand lunar history.<\/p>\n<\/blockquote>\n
And even if GIMLI doesn\u2019t find any caves, it could still determine how the pit formed. It would find more clues about the geologic and volcanic history of the moon overall.<\/p>\n
\nScientists believe that some lunar pits could lead to lava tubes, similar to this one in Hawaii Volcanoes National Park. The moon is home to similar tunnels, left behind after molten lava flows beneath the surface. Image via Frank Schulenberg\/ Creative Commons\/ UCLA.<\/figcaption><\/figure>\n<\/div>\n
\nArtist\u2019s concept of the lunar lava tube in Mare Tranquillitatis. This image depicts the Lunar Reconnaissance Orbiter (LRO) and Earth in space, from the view of the cave opening. Image via University of Trento\/ A. Romeo\/ NASA\/ JPL-Caltech (Brian Kumanchik\/ Christian Lopez)\/ Bill Anders.<\/figcaption><\/figure>\n<\/div>\n
What\u2019s the evidence for lava tubes on the moon?<\/h3>\n
We know there are lava tubes on both Earth, Mars and Venus, so what about the moon?<\/p>\n
Earthly lava tubes only get to about 100 feet (30 meters) across. But on the moon \u2014 with its weaker gravity \u2014 lava tubes might be larger. In fact, scientists estimate they could reach 1,260 feet (385 meters) across.<\/p>\n
Scientists have found nearly 300 pits like Marius Hills Pit on the moon so far. Do any of them lead to subsurface lava tubes? These are the places to go when searching for caves on the moon.<\/p>\n
NASA\u2019s Lunar Reconnaissance Orbiter used radar to investigate one of those pits, in Mare Tranquillitatis, in 2024. The data suggested a possible lava tube about 100 feet long.<\/p>\n
The Marius Hills Pit is another good contender. Radar data from the Kaguya orbiter plus gravity measurements from NASA\u2019s GRAIL mission pointed strongly to a void beneath the surface.<\/p>\n
\nArtist\u2019s conception of a future moon base at the south pole. The other 2 PRISM selections \u2014 LEMS-SP and DISCO \u2014 will help NASA design the base for future Artemis astronauts. Image via NASA.<\/figcaption><\/figure>\n<\/div>\n
Other PRISM selections<\/h3>\n
NASA officially released its first PRISM call for proposals on February <\/strong>14,<\/strong> 2020. The other two PRISM selections include the Lunar Environment Monitoring Station \u2013 South Pole (LEMS-SP) and the Depth Imager with Spectral and Color Optics (DISCO).<\/p>\n
LEMS-SP is an autonomous instrument suite. It is a a long-term environmental and hazard monitoring station. It will monitor falling micro-meteoroids and track the abundance of volatiles. Those are materials that can easily change into gas, that drift into the moon\u2019s thin outer layer of gases.<\/p>\n
Plus, it can also detect seismic activity, ie. moonquakes, with a short-period seismometer.<\/p>\n
No, DISCO won\u2019t play music on the moon. But it will search for ice below the surface in micro-cold traps. In addition, it will study how the lunar surface behaves, from how rocket exhaust disturbs the ground to how stable it is for mobility.<\/p>\n
All of this will help NASA design the first moon base at the south pole. Fox said:<\/p>\n
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These PRISM selections will directly help NASA minimize risks to our astronauts while maximizing our agency goals as we set up humanity\u2019s first lunar outpost in preparation for sending the first astronauts to Mars.<\/p>\n<\/blockquote>\n
Bottom line: NASA is searching for caves on the moon. A new mission, GIMLI, will land at the volcanic Marius Hills Pit to look for a subsurface lava tube. Will it find one?<\/p>\n
Via NASA.<\/p>\n
Via Astronomy.<\/p>\n
Read more: 1st lunar lava tube discovered by NASA moon orbiter<\/p>\n
Read more: Moon caves and pits are a comfy 63 degrees<\/p>\n
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Paul Scott Anderson<\/h4>\n
View Articles\n <\/p><\/div>\n
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About the Author:<\/h6>\n
Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
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\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
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\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
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