Teams from around the US are exploring the possibility of colonizing giant lava tubes beneath the surface of the moon and Mars. Two of them have began testing the necessary equipment here on Earth.
There are two ways a lava tube can form from natural geological activity
When lava flows close enough to the surface the top layer hardens in to a crust. Then after the eruption molten lava flows out of the lower section leaving an empty tunnel. These are called “over-crusted tubes”
When lava is extruded out of cracks and cavities beneath the surface a network of smoother tunnels are formed. These are called “inflated tubes”.
Using high resolution data Colleagues from the University of Padova and Bologna have finished a study comparing lava tube structures here on Earth with those on the moon and Mars. They’ve concluded that these underground fissures are large enough to contain homes, streets and entire communities.
On Earth, they can be up to thirty meters (98.5 feet) across.
In the lower gravity environment of Mars, we see evidence for lava tubes that are 250 meters (820 feet) in width or nearly one quarter of a kilometer.
Whereas on the moon at the lowest gravity of the three, tunnels can spread more than a kilometer wide and many hundreds of kilometers in length. Certainly large enough for a city. In fact some lunar lava tubes are big enough to contain the entire city of Philadelphia.
“These results have important implications for habitability and human exploration of the Moon but also for the search of extraterrestrial life on Mars,” Pozzobon said. “Lava tubes are environments shielded from cosmic radiation and protected from micrometeorites flux, potentially providing safe habitats for future human missions. They are also, potentially, large enough for quite significant human settlements – you could fit most of the historic city center of Riga into a lunar lava tube.”
However, in order for migrants to colonize underground lava tubes they need a method for locating them.
So this is where NASAs “Tube-X Project” comes in to the picture. At Lava Beds National Monument in California, scientists have begun testing a suite of portable tools including a ground-penetrating radar, magnetometer and gravimeter, in order to prepare for non-terrestrial environments.
“There’s never a tube that you get in that’s exactly like one you’ve been in before,”
Luckily for them the tools performed extremely well – complimenting each others weaknesses and allowing for a complete picture of each lava tube to form.
“In general, these tools are incredibly powerful at giving you a real-time look at what you’re standing on and what you’re exploring.”
said Kelsey Young, a geologist at NASA and principal investigator of the TubeX project
“You can’t always tell just from the surface which way the tube is going to go,” Young said. “Some of them can be quite sinuous, and these tubes are incredibly dark.”
This is the teams second visit to the national monument and they spent about a week conducting research..
“Obviously we had an inkling that those instruments would perform well or we wouldn’t have lugged them out here,” Young said.
Tools like this can inform astronauts where dead ends will stifle their search, and where narrow tunnels open up to reveal large swathes of inhabitable space. It also comes in handy for identifying tricky areas filled with rubble or dangerous entryways that have a chance of caving in.
“Until you explore it, it’s just a pit,” Young said.
Another company from Pittsburgh called Astrobiotic Technology has partnered with RIS4E of NASAs Solar System Exploration Research Virtual Institute. RIS4E is a research team that studies in situ, and synchrotron methods for science and exploration
Astrobiotic and NASA eventually plan to send a small drone-like craft called “AstroNav” to explore the lunar underground. The drone is powered by Astrobiotics navigation software and is currently being tested, along with other lunar technology, in the deserts of New Mexico. For two months the drone is expect to undergo rigorous testing as part of the agreement.
Under a research contract with space organization AstroNav will gather, curate and analyze geological samples by deploying modular instruments for different steps in the research process. Astrobiotic is funded in part by the NASA Small Business Technology Transfer program.
“Working with a leading commercial space exploration company like Astrobotic has given the RIS4E team a valuable perspective on how science and exploration can be best combined for future lunar missions,” said Timothy Glotch, from Stony Brook University, which leads the RIS4E team.
The Potrillo Lava Fields in New Mexico
“Working with RIS4E allowed us to work side by side with the planetary geologists for the first time. These field tests gave us a much more practical understanding of each other’s needs and current capabilities, and as a result, we can better design operational concepts, better technologies, and, ultimately, better missions,” said Fraser Kitchell, director of Astrobotic’s Future Missions and Technology team, in a prepared statement.