Seventh graders in a Cottonwood, California, school have been studying lava tubes, a common volcanic feature both on Earth and on Mars. The students were studying Mars-orbiter images and chanced on a small, round, black spot on the 14 km (8.7 mile) high Pavonis Mons, a volcano near the Martian equator whose name means ‘Peacock Mountain’ (top pic).
Skylight on Mars
Experts reckon the students have found a ‘skylight’, a place where the roof of a sub-surface cave has collapsed, and only the second of its kind found on this particular Martian peak.
Caves like these are caused when hot lava punches through rock on its way to the surface during an eruption. The middle picture shows such a lava tube at Lava Beds National Monument, California. The Pavonis Mons cave is reckoned to be a biggie, estimated at some 115 m (380 ft) deep and perhaps 190 m (620 ft) wide. If such caves are common on Mars, and in some areas it’s highly likely, then they could make superb underground bases for future human missions.
Protection from the Sun
The advantages of using natural features like these are massive, not least of which is good protection from the elements. By spraying rock with plastic sealant and installing a suitable airlock, such a cave could be made into a warm, airtight, and comfortable environment. It would also be dust-free, and give the Marsnauts inside excellent protection from the effects of solar radiation on the surface.
Domes first, caves later
While the first Mars explorers (bottom pic) will almost certainly use the familiar dome design for a temporary base, any long-term habitation would be better served by reworking existing Martian natural features.
Valentine Cave picture courtesy Dave Bunnell.
Pavonis Mons, Marsnauts pictures courtesy NASA/Pat Rawlings.