Why we should build astronaut cities in the moon’s and Mars’ lava tubes

Lava tubes on the Moon and Mars may be large enough to accommodate downtown-sized groups of astronauts living on these other worlds, according to a new study.

Lava tubes are an underground tunnel that occurs due to the flow of molten rock during a volcanic explosion. We also have lava tubes on Earth, but those on the Moon and Mars are probably much larger, allowing huge communities of people to work, live, and explore on other worlds.

A typical tube on Earth is about 10 to 30 meters in diameter. But one on Mars could be the height of the Empire State Building, with a diameter 10 times that of Earth. If that sounds big, consider the moon, where its even lower gravity produces a tube up to 1,000 times the size of Earth’s – much taller than the massive Burj Khalifa tower in Dubai.

This is an exciting find because these small cramped spaces on Earth would instead open up into vast caverns of space on other worlds. Rather than imagine future astronauts working side-by-side all the time, these space explorers could easily wander around otherworldly boulevards, all safe from deadly outside radiation (and in the case of March, violent dust storms).

“These [lava tubes] represent ideal gateways or windows for underground exploration, ”study lead author Francesco Sauro said in a statement. Although we’ve known about these lava tubes for some time, the new study shows just how large they are – able to hold the same space as downtown Padua, Italy, in at least one case, Sauro said. .

Sauro is well versed in cave exploration, as he heads the European Space Agency’s Cooperative Adventure Program for the Assessment and Exercise of Human Behavior and Performance Skills (CAVES), which regularly sends astronauts underground in caves to train for space missions using an environment. He is also a caver at the University of Bologna.

The Japanese Kaguya spacecraft (SELENE) was the first to spot these tubes on the moon, according to NASA. Numerous tracking studies have been done using NASA’s Lunar Reconnaissance Orbiter, which takes high-definition images of the moon’s surface from pole to pole. The Orbiter has spotted dozens of intriguing holes and NASA is considering ways in which future missions could delve into them. It might be too steep for a rover, so the agency imagines using swarms of flying or climbing vehicles for exploration.

The researchers used data from images of the moon and Mars and compared it to literature available on Earth from caving (cave exploration) and aerial studies of our own lava tubes. The team also created digital terrain models to get a feel for what those lava tubes on Mars and the moon look like inside, and saw vast possibilities for future exploration.

“What is most important is that, despite the impressive size of the lunar tubes, they remain well below the stability threshold of the roof,” said Matteo Massironi, planetary geologist at the University of Padua who co -wrote the study. The models indicate: he added that most of the lava tubes remain intact and very stable, which means that there is little chance of an underground collapse (also, we can assume that future lunar engineers would be happy to provide a support structure for added security).

So how long can we get on one of these tubes to check things out? NASA plans to land humans on the moon in 2024, accompanied by a suite of private vehicles as part of the Commercial Lunar Services Program (CLPS). At first, these landers and rovers will be focused on supporting human missions, but there is the possibility of adding science payloads to explore the lava tubes.

The first missions to Mars would not take place until the mid-2030s, assuming of course that the funding and will persist long enough to make an international coalition possible. We can only send spaceships there every two years, so a feasibility study for lava tube life would likely be way into the future given the complication of even getting a vehicle in the tube in the first place. .

But perhaps we can be encouraged that NASA’s new Perseverance rover mission is carrying a vehicle that would take the first steps towards exploring the lunar tube on Mars. The Ingenuity helicopter is expected to be the first flying vehicle on the Red Planet, taking off in 2021. If the test mission goes as planned, Ingenuity’s design could be used for many other future Martian flying vehicles, including maybe some who could explore the lunar tubes up close.

A research-based study has been published in Earth-Science Reviews.