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Underground towns on the Moon and Mars: Future human habitats could be hidden in lava tubes

ESA astronauts training in terrestrial lava tubes in Lanzarote during the PANGEA 2016 course

ESA astronauts training in terrestrial lava tubes in Lanzarote during the PANGEA 2016 course. (Click for full view) Photo Credit: L. Ricci / ESA

New research conducted by European scientists suggests that underground caves created by volcanic activity on the Moon and possibly on Mars could be large enough to house even underground towns. The “lava tubes” could, therefore, be excellent hidden locations for future human habitats.

“Our research, conducted jointly by [the] University of Padova and [the] University of Bologna scientists, provides new insights on the size of lava tubes to be expected on Moon and Mars,” Riccardo Pozzobon of the University of Padova in Italy told

The researchers have carried out the first systematic comparison of lava tube candidates on the Earth, the Moon, and Mars, based on high-resolution Digital Terrain Models (DTM) created from data from spacecraft instrumentation. They found that lava tubes on Mars could be up to 820 feet (250 meters) in width. On the Moon, these caves could be even 3,300 feet (one kilometer) or more across and many hundreds of miles in length. On Earth, lava tubes normally only measure around 100 feet (30 meters) across.

“By analyzing the collapse pits found along the lava tube paths on digital terrain models compared with the largest ones on Earth, we have calculated that the size of the voids on Moon and Mars can be up to one or even two orders of magnitude,” Pozzobon noted.

The new findings align with recent research conducted by Dave Blair from Purdue University suggesting that suggest such large lava tubes can be stable in low gravity conditions. The study conducted by Pozzobon and his colleagues appears to confirm that huge voids could exist in the subsurface of both Mars and on the Moon.

Artist’s impression of the radar instrument to probe for lava tubes beneath the lunar surface.

Artist’s impression of the radar instrument to probe for lava tubes beneath the lunar surface. Image Credit: U. Trento / NASA

Moreover, the existence of one large open lava tube on the Moon was lately confirmed by scientists analyzing radar data from Japan’s SELENE lunar orbiter. The spacecraft orbited the Moon between October 2007 and June 2009, studying its origins and geologic evolution. Data gathered from SELENE allowed the researchers to find an enormous cavern that stretches for about 30 miles (50 kilometers) in the Marius Hills region.

Lava tubes are naturally occurring channels formed by flowing lava which moves beneath the hardened surface of a lava flow. These structures could prove important for future space exploration missions, providing shelter from cosmic radiation, extreme temperature, and meteorite impacts.

“The possibility to establish a settlement within a lava tube provides benefits both in economic and safety terms. The thick roofs shields from cosmic radiation and meteorites, but also reduces daytime/nighttime thermal excursion, providing a thermally controlled environment as happens in terrestrial caves,” Pozzobon said.

Large voids on the Moon and on Mars could possibly contain a human settlement. The possible size of lunar lava tubes means that they could be large enough to host significant settlements like underground towns with streets.

However, in order to better understand lava tubes beyond Earth and to precisely pinpoint their location, more studies are required. According to Leonardo Carrer of the University of Trento in Italy, one of the co-authors of the new research paper, future robotic missions equipped with specialized instruments could help us improve our knowledge about extraterrestrial lava tubes.

“Our research, performed at the Remote Sensing Laboratory [RSLab] of the University of Trento, shows that, by using an orbiting radar using very low electromagnetic frequencies, it is possible to directly probe the subsurface of the Moon and infer the concealed lava tubes size and physical composition. Therefore our concept study proves that a future orbital mission carrying this type of instrument could greatly improve our knowledge regarding these structures and their location. Moreover, the global mapping would be a crucial information for selecting the best site for establishing a human outpost,” Carrer told

He added that Mars rovers, such as Curiosity and Opportunity, which are currently operating on the Red Planet, could help estimate the local environmental conditions, morphologies, and to verify the actual volume of the voids. Sending human-made objects within such cavities would also serve to push forward remote operational capabilities in difficult environments and to develop new roving abilities.

Currently, Pozzobon and Carrer are in the process of scanning the interior of one of the largest terrestrial lava tubes to gain a better understanding of extraterrestrial caverns. They want to relate the results with digital terrain models of the collapsed roof traces seen from satellite photos, so as to have a fully complete understanding of its surface-subsurface three-dimensional framework.

“Regarding other planetary bodies, up to now there is no evidence of lava tubes on other bodies apart from Moon and Mars, but I have great expectations on the data that will eventually come out from ESA-JAXA BepiColombo mission to Mercury, that is going to be launched next year,” Pozzobon concluded.



Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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