HR: 0800h
AN: P51B-0491    [Abstracts]
TI: Electrostatic Levitation of Lunar Dust: Preliminary Experimental Observations
AU: * Marshall, J
EM: jmarshall@seti.org
AF: SETI Institute, 515 N Whisman Rd, Mountain View, CA 94043, United States
AU: Davis, S
EM: sdavis@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035, United States
AU: Laub, J
EM: j.laub@comcast.net
AF: SETI Institute, 515 N Whisman Rd, Mountain View, CA 94043, United States
AB: A lunar dust laboratory has been established in the Space Science Division at NASA Ames to evaluate fundamental electrostatic processes at the Moon's surface. Photoelectric charging, triboelectric charging, and interactions of these processes are investigated for dust-size materials. An electric field simulating the solar- plasma induced E-field of the lunar surface has been created with parallel charged capacitance plates. The field is linear, but field-shaping to create lunar-like exponentially decaying E-fields will be conducted in the near future. Preliminary tests of dust tribocharging have been conducted using a vibrating base plate within the electric field and have produced electrostatic levitation of 1.6 micron diameter silicate particles. We were able to achieve levitation in a modest vacuum environment (1.7 Torr) with the particles charged to approximately 15 percent of the Gaussian limit (defined as 2.64 E-5 C/m-2 for atmospheric air) at a threshold field strength of 2250 V/m. This charging corresponds to only a few hundred (negative) charges per particle; the field strength drops to 375 V/m when gravitationally scaled for the Moon, while dust tribocharging to greater than 100 percent of the Gaussian limit would be possible in the ultra high vacuum environment on the Moon and result in even lower threshold field strengths. We conclude therefore, that anthropogenic disturbance of lunar dust (as a result of NASA's proposed base construction, mining, vehicle motion, etc) could potentially pollute the lunar environment with levitated dust and severely impair scientific experiments requiring a pristine lunar exosphere.
DE: 2461 Plasma interactions with dust and aerosols (7849)
DE: 6250 Moon (1221)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting