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Friday, November 23, 2012

LADEE to Investigate Lunar Atmosphere


"By night the Glass Of Galileo ... observes Imagin'd Land and Regions in the Moon." - John Milton (Paradise Lost - 1667)
 
Most view the moon as having no atmosphere. Yet the 'lunar atmosphere' -  less than one hundred trillionth of Earth's atmospheric density at sea level - may be caused by multiple sources as science lifts the veil to gain more knowledge of the dusty environment.
 
Clementine moon probe
The Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA robotic mission that will orbit the moon to gather detailed information about the lunar atmosphere, conditions near the surface and environmental influences on lunar dust. The mission is set to launch from the Mid-Atlantic Regional Spaceport at Wallops Island in August 2013 - the first deep space probe ever launched from Virginia.
 
The latest lunar probe will examine the composition of the lunar atmosphere by analyzing light signatures of materials it finds, measure variations in the lunar atmosphere over multiple lunar orbits with the moon in different space environments, and collect and analyze samples of any lunar dust particles in the tenuous atmosphere. The probe will add significantly to human knowledge of the lunar environment and it may answer several puzzling questions.
 
In short, "LADEE will investigate this moon magic trick of levitating lunar dust," notes Live Science journalist Leonard David.
 
Boston University study
Nearly two decades ago, scientists found the wispy atmosphere of the Moon extends at least 9,000 miles above its surface through the faint glow of sodium gas. The most likely explanation is the evaporation of atoms from the lunar surface when it is struck by light particles called photons coming from sunlight. Sodium and other elements escape the surface through erosion caused by the bombardment of photons, as well as heat from sunlight warming surface materials
 
Clementine moon probe photo
Evidence has mounted that the tenuous atmosphere of moving dust particles constantly leaping up from and falling back to the Moon's surface, giving rise to a "dust atmosphere." The term "Moon fountain" has been used to describe this effect by analogy with the stream of molecules of water in a fountain following a ballistic trajectory while appearing static due to the constancy of the stream caused by electrostatic levitation.
 
Lunar atmosphere studies
Positive charges build up until the tiniest particles of lunar dust (measuring 1 micrometre and smaller) are repelled from the surface and lofted anywhere from metres to kilometres high, with the smallest particles reaching the highest altitudes. Eventually they fall back toward the surface where the process is repeated over and over again. On the night side, the dust is negatively charged by electrons in the solar wind. Indeed, the fountain model suggests that the night side would charge up to higher voltages than the day side, possibly launching dust particles to higher velocities and altitudes.

This past August 2012, NASA's Lunar Reconnaissance Orbiter detected helium in the moon's tenuous atmosphere, confirming observations made four decades ago on the lunar surface, corroborating measurements made by the Lunar Atmosphere Composition Experiment (LACE), which was deployed by moonwalking Apollo 17 astronauts in 1972, noted MSNBC.

Lunar Industries: "Moon" movie
LADEE's mission is one of importance in our understanding of the Moon, its atmosphere, and how subsequent human interaction in the coming two-world system development will impact its future. Humans are expected to return to the Moon's surface in the next decade and begin to develop human outposts and lunar industries on the surface. The surface and atmospheric dust must be better understood by future astronauts, cosmonauts, taikonauts and robonauts expected traverse its regolith, lava tubes and craters.

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