Thursday, September 4, 2008

NASA reaches out to students to help with the Moon's "dust problem"

At the top of the National Space Studies Board's priority recommendations, not to mention that of Apollo 17 veterans Captain Cernan and Senator Schmitt, is coming to grips with sub-micron lunar dust, which "literally gets into everything," Cernan recently said.

"And when I say 'everything,' I mean everything," Cernan reiterated, saying he had to wait for his fingernails to grow out before becoming apparently free from the finest of the fine lunar basalts that were originally thought to be similar to the shinny volcanic melt hardening after a lava flow cools back on Earth. After billions of years of bombardment by solar wind and cosmic rays, however, the smooth glassy melt of the lunar seas, for example, becomes split to consituent particles ranging from artifact agglutenates to grey dust too small to be visible to the naked eyes.

To complicate matters, the finest particles, when negatively charged by the steady proton wind of the sun, may actually levitate and eventually precipitate with a subsequent positive charge. The lunar daily cycle isn't much of a visible rain, though it may scatter light over the horizon to become the "terminator glow" first imaged by Surveyor landers 40 years ago, and later by astronauts Borman, Lovell and Anders during their pioneering ten orbits of the Moon in December 1968.

Will the Apollo landing sites, pictures of which are a primary target of Lunar Reconnaissance Orbiter, be covered by a thin precipitate of grey dust? Likely now, say experts, citing the little dust that was found on Surveyor 3 when cannibalized by Conrad and Bean after their landing 150 meters away from where it had landed (twice) three years before their pinpoint landing of Apollo 12 in November 1969.

Most of the dust and damage from dust later found on examining the parts of the lander that were retrieved and returned by Apollo 12 was discovered to be a result of the approach of the Apollo 12 Lunar Module descent stage. It has been pointed out, however, that the same rich spray picked up by Apollo 12 on approach might not just have impacted Surveyor but also have blown any incidental dust off the tiny unmanned vehicle.

Ian O'Neill, in the indispensible Universe Today, has written a "fine" article showing one of the many collaborative efforts NASA is utilizing to arrive at needed solutions, to preserve the integrity of delicate tools and lungs, not to mention hatch seals and such, when NASA returns to the Moon a decade from now.

Experiments have shown the pesky dust is more stubborn than beach sand in your shoes at the shore, with the integrity of vacuum bottle seals and the like best protected by a burst of pressurized gas, which does not completely work, and best treated with a gentle wipe by hand. This last method has been shown to work best, but still caused abrasion on seals and causing them to eventually fail as well.

But the Moon is out destiny, and solving the problem remains the highest priority for program planners. The LADEE probe, scheduled for launch in 2011, is being designed to probe the migratory habits of sub-micron dust, but planners are still struggling with coming up with a definitive method of measuring the dust, if only by inference, as studies continue.

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