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Lunar Surface Potential Increases during Terrestrial Bow Shock TraversalsSince the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. We present an analysis of Apollo 14 SIDE "resonance" events that indicate the lunar surface potential increases when the Moon traverses the dawn bow shock. By analyzing Wind spacecraft crossings of the terrestrial bow shock at approximately this location and employing current balancing models of the lunar surface, we suggest causes for the increasing potential. Determining the origin of this phenomenon will improve our ability to predict the lunar surface potential in support of human exploration as well as provide models for the behavior of other airless bodies when they traverse similar features such as interplanetary shocks, both of which are goals of the NASA Lunar Science Institute's Dynamic Response of the Environment At the Moon (DREAM) team.
Document ID
20090026593
Document Type
Other
Authors
Collier, Michael R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Stubbs, Timothy J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hills, H. Kent (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Halekas, Jasper (California Univ. Berkeley, CA, United States)
Farrell, William M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Delory, Greg T. (California Univ. Berkeley, CA, United States)
Espley, Jared (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Freeman, John W. (Rice Univ. Houston, TX, United States)
Vondrak, Richard R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kasper, Justin (Lunar Science Inst. Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
May 15, 2009
Subject Category
Lunar and Planetary Science and Exploration
Distribution Limits
Public
Copyright
Other