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Measurements of Charging of Apollo 17 Lunar Dust Grains by Electron ImpactIt is well known since the Apollo missions that the lunar surface is covered with a thick layer of micron size dust grains with unusually high adhesive characteristics. The dust grains observed to be levitated and transported on the lunar surface are believed to have a hazardous impact on the robotic and human missions to the Moon. The observed dust phenomena are attributed to the lunar dust being charged positively during the day by UV photoelectric emissions, and negatively during the night by the solar wind electrons. The current dust charging and the levitation models, however, do not fully explain the observed phenomena, with the uncertainty of dust charging processes and the equilibrium potentials of the individual dust grains. It is well recognized that the charging properties of individual dust grains are substantially different from those determined from measurements made on bulk materials that are currently available. An experimental facility has been developed in the Dusty Plasma Laboratory at MSFC for investigating the charging and optical properties of individual micron/sub-micron size positively or negatively charged dust grains by levitating them in an electrodynamic balance in simulated space environments. In this paper, we present the laboratory measurements on charging of Apollo 17 individual lunar dust grains by a low energy electron beam. The charging rates and the equilibrium potentials produced by direct electron impact and by secondary electron emission process are discussed.
Document ID
20080015655
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Abbas, Mian M. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Tankosic, Dragana (Alabama Univ. Huntsville, AL, United States)
Spann, James F. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Dube, Michael J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
February 10, 2008
Subject Category
Geophysics
Meeting Information
Meeting: Space Technology and Applications International Forum (STAIF-2008)
Location: Albuquerque
Country: Mexico
Start Date: February 10, 2008
End Date: February 14, 2008
Distribution Limits
Public
Copyright
Public Use Permitted.

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