From: Kathy Kasten <catraja.nul> Date: Fri, 15 Jul 2011 18:18:04 +0000 Archived: Fri, 15 Jul 2011 20:32:53 -0400 Subject: Planetary Cave Dwelling The Planetary Report; Volume 31; Number 3 June Solstice 2011: wwwplanetary.org Page 11-15; Planetary Cave Dwelling; A Strategy for Exploration by Jacques Blamont Professor Emeritius University of Paris [Begin Citation] Missions to Mars with humans aboard will face several challenging requirements for sheltering their crews. First is the radiation in the natural environment, a combination of galactic cosmic rays, solar particle events, and secondary radiation from the interaction of both of these with atmosphere and soil. Radiation would rise to peak levels during large solar eruptions, which occur one to three times per 11-year solar cycle. <snip> Using caves as habitats provides an intriguing possibility: the total dose (of radiation) equivalent for the same mission in a cave habitat would be 0.212 mSv (as opposed to the 540-day dose of 14,795 millisieverts, or mSv). Caves two or three meters below the surface can provide effective shielding, although a more conservative five-meter depth would give greater assurance of protection. (To date, no cost efficient shielding system has been engineered for Mars missions.) <snip> Caves also protect against temperature extremes at the Martian surface and make it easier to manage air filtration. Apollo missions showed that lunar dust is a health risk, triggering inflammatory lesions in lungs. Martian dust is even riskier because of oxidants. In caves, keeping the dust out is simply a problem that good engineering at the entrances could solve. Shielded from dust storms, structures and equipment would require less maintenance. <snip> Caves Near Volcanoes Mars has a ready supply of potentially habitable caves in the form of lava tubes. A lava tube results from a low-viscosity (fast-running) stream of lava cooling and solidifying on the outside while continuing to flow on the inside. When the last of the lava runs out, an empty cylinder remains, with smooth surfaces on the floor, walls and ceiling. <snip> Underground lava tubes become accessible when a section of the roof collapses, creating a pit, or skylight, and exposing two cave openings. After a skylight opens, other parts of the lava tube can remain geologically stable, surviving intact for millions of years. Guidelines for selecting stable and otherwise suitable caves will have to be developed, drawing on research of analog sites on Earth and the Moon. <snip> One limitation of lava tubes is their obligatory presence in volcanic terrains. The best sites for a Mars base will be at the lowest possible altitude and the highest possible latitude, with the hope of finding subterranean ice. Syrtis Mons, Nili Fossae, and Mawrth Vallis are regions that could contain lava tubes and offer scientific interest. Many lava tubes also will be found in the lava beds around Alba Patera and in the volcanic regions apart from Tharsis shield, such as Elysium. Several pit craters that may be skylights already have been identified on Mars. In 2007, Glen Cushing of the U.S. Geological Survey and colleagues compared images from the HiRISE camera aboard Mars Reconnaissance Orbiter with images from the THEMIS thermal mapper aboard Mars Odyssey and reported seven possible lava tubes on the slopes of Arisia Mons. The craters range in diameter from 100 to 225 meters. Another hole was found in 2010 on Pavonis Mons. On Earth's Moon, the Japanese SELENE imager discovered holes indicating the presence of underground lava tubes. [End of citation] The rest of the article discusses the material requirements for plants and humans, and how those needs could be met. Very exciting concepts are being developed for providing for astronauts to be able to live on other planets. KK Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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