This paper examines the feasibility of a multi-kilowatt wireless radio frequency (RF) power system to transfer power between lunar base facilities. Theanalyses show that wireless power transfer (WPT) systems can be more efficient and less expensive than traditional wired approaches for certain lunar and terrestrial applications.We already have the available technology necessary to make large solar arrays on the moon, and then use wireless power transmission via microwaves to send the resulting electricity back to earth. Although the upfront cost would be high, it wouldn't be impossible. The study includes evaluations of the fundamental limitations of lunar WPT systems, the interrelationships of possible operational parameters, and a baseline design approach for a notional system that could be used in the near future to power remote facilities at a lunar base. Our notional system includes state-of-the-art photovoltaic (PVs), high-efficiency microwave transmitters, low-mass large-aperture high-power transmit antennas, high-efficiency large-area rectenna receiving arrays, and reconfigurable DC combining circuitry.

1. Prof. ZoyaPopovic, University of Colorado, Boulder, David R. Beckett, Scott R. Anderson, Diana Mann, Stuart Walker, Independent Consultants Sheldon Fried, Ph.D., National Security Technologies, LLCLunar Wireless Power Transfer Feasibility Study, March 2008.
2. N.D. Lopez, J. Hoversten, M. Poulton, Z. Popovic, “A 65-W High-Efficiency UHF GaNPower Amplifier,” accepted for presentation at the IEEE International Microwave Symposium,Atlanta, June 2008.
3. T. Paing, J. Morroni, A. Dolgov, J. Shin, J. Brannan, R. Zane, Z. Popovic, “Wirelessly-Powered Wireless Sensor Platform,” European Microwave Conference Digest, paper 1563,4 pages, presented in Munich, Germany, October 2007.
4. M.J. O’Neill, International Conference on Solar Concentrators for the Generation ofElectricity or Hydrogen, Scottsdale, May 1–5, 2005, “ENTECH’s Stretched Lens Array (SLA) for NASA’s Moon/Mars Exploration Missions, Including Near-Term Terrestrial Spin-Offs.”
5. M.J. O’Neill, 4th World Conference on Photovoltaic Energy Conversion, Waikoloa, Hawaii,May 7–12, 2006, “Stretched Lens Array (SLA) for Collection and Conversion of Infrared LaserLight: 45% Efficiency Demonstrated for Near-Term 800 W/kg Space Power System.”
6. USPTO Patent Application 20070090476, SURFACE-EMISSION CATHODES HAVINGCANTILEVERED ELECTRODES, Michael W. Geis, et al. (Massachusetts Institute ofTechnology), 2007.

Photovoltaic Rectenna Microwave transmitter Rectenna array stretched lens array Load station