Mysterious Moon Caves: a Shelter for Future Colonists Or Something More?
2nd Feb 2025
Ever since Neil Armstrong left the first trace of humanity in the lunar dust, scientists have hypothesised about the existence of underground voids on our satellite, which may have formed billions of years ago as a result of volcanic activity. Caves on the Moon remained a mystery for over 50 years, and finally, quite recently, their secret has been revealed. This time we will discuss everything scientists know about the Moon caves nowadays: what makes them special and what role they may play in future colonisation.
What is a lunar cave?
Billions of years ago, volcanoes erupted on the Moon. Hot lava flowed across the surface while its upper layer gradually cooled and hardened, forming a “crust.” Under this crust, the lava continued to flow, burning a void in the lunar rocks. When the eruption ended, the lava flowed out, leaving behind a long hollow tunnel — a lava tube. These underground tunnels are the Moon caves.
How Did They Find Caves on the Moon?
Since the mid-20th century, scientists have assumed that underground cavities similar to lava tubes on Earth may exist on our satellite. The hypothesis was actively developed at the beginning of Moon exploration. Various geologists and planetologists, studying images of the lunar surface obtained from spacecraft, tried to find lunar pits, which could indicate potential places to form caves.
What are lunar pits? Imagine lava tubes formed billions of years ago, the ceiling collapsed under meteorite impacts or other factors. As a result, a hole appeared on the surface, forming a kind of skylight that opens up the entrance to an underground cavity.

In 2009, the Japanese probe Kaguya, while conducting a topographic survey of the lunar surface with a resolution of 15 km, discovered the first lunar pit in the Marius Hills area.
A year later, NASA’s Lunar Reconnaissance Orbiter (LRO), equipped with more powerful cameras and radars, produced a 3-D map of our satellite’s surface with a resolution of 100 meters and 98.2 per cent coverage, including images of the Apollo landing sites at a resolution of 0.5 meters. This allowed researchers to discover even more pits that may have been caused by the collapse of hardened lava tubes.
The final verdict on the existence of moon caves was given by an international team of scientists led by Leonardo Carrera from the University of Trento in Italy in 2024. After re-analyzing data from the LRO SAR (Miniature Radio-Frequency instrument (Mini-RF)), the team discovered a large lava tube in the Sea of Tranquillity region, 230 miles northeast of where Neil Armstrong and Buzz Aldrin landed. This cave, which is believed to extend for 200 feet, became the first confirmed evidence of the existence of an underground world on our satellite.
How Many Caves Are There on the Moon?
The exact number of moon caves remains a mystery. Underground tunnels can extend for hundreds of kilometres. How many pits are on the Moon? So far, scientists have managed to find about 200 potential entrances to lava tubes. Unfortunately, modern technology does not allow us to identify more due to the difficult terrain and imperfect remote sensing methods.
Where Are Moon Caves Located?
Besides the Sea of Tranquility, scientists have also found potential lava tubes in such areas as:
- Marius Hills — a group of volcanic domes located in the Ocean of Storms (Oceanus Procellarum). These domes were formed from lava that was more viscous than that which formed the lunar seas. The height of the domes ranges from approximately 200 to 500 meters.
- Mare Serenitatis (Sea of Serenity) is a lunar sea 674 m in diameter, located east of the Sea of Rains (Mare Imbrium). The basalt of the sea covers most of the basin and flows into the Lake of Dreams (Lacus Somniorum) in the northeast. The most notable feature is the crater Posidonius on the northeastern edge of the sea.
- Mare Imbrium (Sea of Rains) — a vast lava plain within the Imbrium Basin. It is one of the largest impact basins on the visible side of our satellite. The basin is approximately 1,160 km in diameter. Mare Imbrium was formed by a gigantic ancient cosmic impact and then filled with lava that cooled and turned into dark rock.
These areas are of greatest interest for studying moon caves, but how is NASA going to do this and, most importantly, for what purpose?
Lunar Caves And the Artemis Program: New Opportunities For Space Exploration
The discovery of caves on the Moon takes on special significance in the context of the Artemis program, NASA’s effort to return humans to the Moon and create a permanent moon base. These underground shelters could be key to a successful lunar environment and colonisation.
How Can Caves Help Future Colonists?
- Protection from harsh environment: A thick layer of lunar soil serves as a natural shield from solar radiation, meteorites and lunar surface temperature variations. Inside the lava tubes, the temperature is constant at around -20°C, which is much more comfortable than on the surface, where the temperature fluctuates between +120°C and -170°C.
- Space to live and work: Lava tubes can be hundreds of meters wide and kilometres long, providing ample space for housing modules, research labs, warehouses, and other infrastructure, such as transport tunnels linking colonies.
- Access to resources: Underground cavities may contain water ice, which can be used to produce water and rocket fuel. In addition, the lunar soil contains rare metals and helium-3, which may become an energy source in the future.
How Is NASA Going to Explore the Moon Caves?
Besides LRO, NASA is counting on several other projects that should help study the structure of moon caves and determine their potential usefulness for lunar missions.
BRAILLE

The BRAILLE (Biologic and Resource Analog Investigations in Low Light Environments) project is a NASA initiative to develop and test technologies for exploring volcanic caves, primarily on Mars but with potential applications on the Moon. The project uses a Spot quadruped robot developed by Boston Dynamics and a CaveR wheeled robot equipped with cameras, LIDARs, spectrometers, and other instruments to operate in low- or no-light environments, allowing them to explore, map, and assist in remote astrobiology research. Testing is underway at various locations on Earth, including the Lava Tubes of California’s Lava Beds National Monument and New Mexico.
CADRE
The project, which stands for Cooperative Autonomous Distributed Robotic Exploration, aims to deploy a network of small autonomous robots to explore the lunar surface, including potential underground tunnels. These robots can coordinate their actions without human intervention, which allows them to effectively collect scientific data under challenging conditions.
Skylight
Skylight is another robotic project aimed at exploring and modelling lunar pits and underground cavities. The key difference of Skylight is its use of tethered microrobots that can descend into the pits and explore the underground structures. The robots create high-quality 3D models of these structures, helping scientists understand their potential for human habitation.
These projects, which can be conditionally united under a single name, “NASA operation “big cave,” are aimed at making the exploration of the Moon and Mars safer and more efficient, as well as expanding our knowledge of the geology and history of these celestial bodies.
From Space to Dungeon And Back

When Neil Armstrong stepped onto the lunar surface, he didn’t even think, are there caves on the moon. The discovery of moon caves is not just a scientific sensation; it is an important step towards space exploration. These mysterious space dungeons open up incredible opportunities for us: creating permanent lunar bases, conducting unique scientific research, mining, and much more. What today may become the first refuge for lunar colonists, tomorrow may serve as a springboard for further human expansion in the Universe. After all, the next stop after the Moon is Mars, and there are probably underground worlds there as well that we will have to explore.
References and Additional Information:
- Radar evidence of an accessible cave conduit on the Moon below the Mare Tranquillitatis pit https://www.nature.com/articles/s41550-024-02302-y.epdf
- New Evidence Adds to Findings Hinting at Network of Caves on Moon https://science.nasa.gov/solar-system/new-evidence-adds-to-findings-hinting-at-network-of-caves-on-moon/
- NASA Braille https://nasa-braille.org/about-braille/
- Cooperative Autonomous Distributed Robotic Exploration https://www.nasa.gov/cooperative-autonomous-distributed-robotic-exploration-cadre/
- Technologies Enabling Exploration of Skylights, Lava Tubes and Caves https://www.nasa.gov/wp-content/uploads/2017/07/niac_2011_phasei_whittaker_lavatubesandcaves_tagged.pdf
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