NASA's Lunar Reconnaissance Orbiter, using the on-board Lyman Alpha Mapping Project, or LAMP, spectrometer, has detected the presence of helium in the thin atmosphere of the moon, by examining far ultra violet rays above the lunar surface. The finding, detected over the course of 50 orbits made by the spacecraft around the moon, took into account the helium that could be from interplanetary background. Care was taken to remove signal contributions from such background helium to determine the amount of the element native to the moon.
The finding complements the measurements made by the Lunar Atmosphere Composition Experiment, or LACE, of the Apollo 17 mission in 1972.
According to Dr. Alan Stern, LAMP principal investigator and associate vice president of the Space Science and Engineering Division at Southwest Research Institute, Colorado, "The question now becomes, does the helium originate from inside the Moon, for example, due to radioactive decay in rocks, or from an exterior source, such as the solar wind?"
He added "If we find the solar wind is responsible, that will teach us a lot about how the same process works in other airless bodies."
According to the researchers, if the spacecraft observations do not reveal such correlation, radioactive decay or other internal processes on the satellite could be producing the helium which is released during lunar quakes or dispersed from the interior.
The principal investigator Dr. Stern said, "With LAMP's global views as it moves across the Moon in future observations, we'll be in a great position to better determine the dominant source of the helium."
Another focus of research would be the phenomenon of helium abundances. The LACE observations of the 1970s showed an increase in helium abundances as the night progressed due to atmospheric cooling , which concentrated atoms at lower altitudes. LAMP will investigate this phenomenon further by measuring how helium abundance varied with latitude.
LAMP will also look to detect the presence of Argon and other gases on the lunar surface that were earlier detected by LACE.
The finding was published in the journal Geophysical Letters in 2012.
by RTT Staff Writer
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