Huge lava cave could offer optimum protection for astronauts

Perfect for a moon station: Researchers have discovered a huge lava cave on the moon. The cave is located in an old volcano in the Ocean of Storms and is several kilometers big. It could offer the inhabitants of a future moon station perfect protection against the cosmic radiation and the temperature fluctuations of the lunar surface, as the scientists report.

The moon probe Selene has discovered a huge lava cave in the Ocean of Storms. It could become the location for a future moon station. © JAXA / SELENE / Crescent / Akihiro Ikeshita for Kaguya image

Recently, US Vice President Mike Pence has announced that the US government is seeking a return to the moon. The Earth's moon is supposed to become an intermediate station and test field for manned space travel to Mars, but also attracts valuable raw materials - which is why private companies have already developed plans for manned lunar missions.

Cave with a hole in the ceiling

The suitable habitat for future moon astronauts could now have been discovered by scientists from the Japanese space agency JAXA together with US colleagues. In the evaluation of data from the moon probe Selene, they found a striking signature in the Marius Hills region in the Ocean of Storms: the radar data showed a double echo during the illumination of the underground - a reference to a cavity under the surface.

Remarkable: Previously, at this point researchers had discovered a 50-meter-long hole in the lunar surface. Even then they suspected that it could be a so-called skylight - an opening in the ceiling of a lava cave. These cavities are formed when lava solidifies on the surface, but continues to flow below. On the Earth, lava caves are mainly known from Hawaii.

Relic of a lava flow stream

The fact that such lava caves can also exist in the lunar Ocean of Storms, scientists suspect for a long time. Because the entire valley was once flooded by lava, later volcanic domes formed in the region of Marius Hills. From these, winding valleys and columns, which are very similar to the lobed lava slopes, emerge. As early as 2015, researchers speculated about the existence of intact lava caves in this area.

Now new data confirm this presumption. After the radar measurements of the Selene probe gave first indications for the existence of a large lava cave, Jay Melosh and his team from the Purdue University evaluated additional gravity field data from the GRAIL space probe.

Using these gravity field data, we were able to determine how large and deep these lava caves are, explains Melosh.

Big enough for a moon station

The result: The lava cave near the Marius Hills is probably about 50 kilometers long and could be up to a kilometer wide and high. It would be large enough to accommodate a whole city, or a large moon station, as the researchers explain. There could even be water ice in this cavity under the surface of the moon.

For a future lunar station this lava cave could therefore be a perfect location. Because the moon has no atmosphere and no magnetic field, astronauts would be exposed to the hard radiation from space, unprotected on its surface. Also the extreme temperature differences between day and night are a hard burden for humans and material. In the lava cave, on the other hand, a future lunar habitat would be protected against radiation and temperature extremes.

Source: Geophysical Research Letters