- 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.