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| Title: |
Measurements of Charging of Apollo 17 Lunar Dust Grains by Electron Impact
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| Author(s): |
Abbas, Mian M.; Tankosic, Dragana; Spann, James F.; Dube, Michael J.
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| Abstract: |
It 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.
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| NASA Center: |
Goddard Space Flight Center; Marshall Space Flight Center
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| Publication Date: |
February 10, 2008
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| Document Source: |
CASI |
| No Digital Version Available: |
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| Document ID: |
20080015655
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| Publication Information: |
Number of Pages = 9 |
| Price Code: |
A02 |
| Meeting Information: |
Space Technology and Applications International Forum (STAIF-2008), 10-14 Feb. 2008, Albuquerque, Mexico |
| Keywords: |
LUNAR DUST; PHOTOELECTRIC EMISSION; AEROSPACE ENVIRONMENTS; ELECTRON EMISSION; ELECTRON IMPACT; LUNAR SURFACE; SOLAR WIND; SECONDARY EMISSION; OPTICAL PROPERTIES;
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| Accessibility: |
Unclassified; Copyright; Unlimited; Publicly available; |
| Updated/Added to NTRS: |
2008-04-28 |
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