Lava Tubes May Make
Lunar And Martian Homes
By Michael Ray Taylor
Discovery News Brief

Giant lava tubes on the moon and Mars could provide low cost, ready-built enclosures for future lunar bases, say a trio of researchers working under a NASA grant.
The researchers presented their findings last week at the International Space Development Conference in Houston.
By comparing lava tubes on Earth with astronomical data suggesting collapsed caverns on the moon, team members calculate that caves up to 400 meters wide should exist in several places near the lunar surface.
They believe that the lava tubes on Mars will have slightly smaller diameters, but may in some cases extend for hundreds of miles along the slopes of ancient shield volcanoes.
"The diameter of a lava tube is the function of the gravity where the lava flows -- with less gravity, you get very large diameters," says team member Cheryl York, president of the Oregon-based L5 Lunar Base Research Team.
York says features on the moon such as the Hadley Rill, a meandering lunar valley, are often interrupted by smooth sections, as though parts of a collapsed lava tube remain intact.
New data from the Clementine lunar probe and the Mars Global Surveyor seem to point to dozens of previously undetected lava tube systems existing near the surface of both worlds, York says.
After testing lightweight plastic liners and construction methods in Oregon lava tubes, the team concluded that pressurized enclosures could be built by small crews at a fraction of the cost and effort required to build planetary habitats on the surfaces of the moon or Mars.
Such habitats would provide thermal insulation and would protect people and equipment from damaging solar radiation.
"Apollo measurements found that just a few feet down into the lunar surface the temperature is a constant 20 degrees below zero Celsius," team member Bryce Walden says. "That's no colder than Minnesota in the wintertime."
The Oregon caves studied by the team had thin ceilings but were still capable of supporting tons of weight. The team expects cave ceilings on the moon and Mars to be up to 10 times thicker and more than 100 times stronger than those on Earth.
"The use of lava tubes for future habitats on the Moon and Mars is a very plausible idea and one that we have been exploring for more than a decade," says Cassandra Coombs, assistant professor of Geology at the College of Charleston.