Electricity from Orbit: The case for R & D
38Google Tech Talks
December, 5 2007
ABSTRACT
Cost-effective space solar power (SSP) -- the beaming abundant high-intensity solar power from space though atmospheric windows at laser or microwave frequencies for electric power at the surface -- could be a breakthrough technology for large-scale power generation, highly flexible power distribution and sustainable carbon-neutral base load for Earth; a goal comparable, but much closer to engineering maturity, to that of controlled thermonuclear fusion. Apart from much higher than the surface mean solar flux, continuous sunlight in space avoids otherwise cost-pacing massive storage and transmission of intermittent terrestrial solar and windpower to match electric demand curves. Access to space cost reductions will likely be driven by economies of scale from commercialization. But SSP would be markedly accelerated by experiments feasible now, some employing ISS, including orbital mirrors and microwave and and laser beaming in space.
The just-released report on SSP by the National Security Space Office (available at http://www.nss.org/settlement/ssp/library/nsso.htm) concludes that "it would be in the US Government's and the nation's interest to sponsor an immediate proof-of-concept demonstration project and a formally funded, follow-on architecture study conducted in full collaboration with industry and willing international partners." For example, I will describe our proposed demo of wireless power transmission from geosynchronous orbit (GEO) using diode laser transmitters in space and surface PV module receivers employing a self-deploying single launch one metric tonne satellite payload. Because diffractive beam spreading requires large antennas at microwave frequencies, it would be virtually impossible to launch microwave beamers large enough for efficient space-to-Earth power transfer without expensive multiple launches and in-space assembly. This limitation is overcome with the laser-based system proposed here although commercial SSP power stations might well utilize microwave beaming down the road.
This experiment would demonstrate continuous electric power transfer from orbit orders of magnitude greater than anything done before, perhaps powering a remote village off the grid in the developing world. With near term and "on the shelf" components and early launch opportunities like NASA's Geo QuickRide, piggybacks on communication satellite launches, and the ISS as testbed, near term experiments could accelerate SSP from paper studies to a real alternate energy option in as little as a three to five year time frame at relatively modest cost.
Speaker: Marty Hoffert
Martin I. Hoffert is Professor Emeritus of Physics and former Chair of the Department of Applied Science at New York University. His academic background includes a B.S. (1960) in Aeronautical Engineering from the University of Michigan, Ann Arbor; M.S. (1964) and Ph.D. (1967) from the Polytechnic Institute of Brooklyn (now the Polytechnic Institute of New York) in Astronautics; and a Master of Arts in Liberal Studies, M.A.L.S. (1969) from the New School for Social Research where he did graduate work in sociology and economics.
He has been on the research staff of the Curtiss-Wright Corporation, General Applied Science Laboratories, Advanced Technology Laboratories, Riverside Research Institute and National Academy of Sciences Senior Resident Research Associate at the NASA/Goddard Institute for Space Studies. Prof. Hoffert has published broadly in fluid mechanics, plasma physics, atmospheric science, oceanography, planetary atmospheres, environmental science, solar and winds energy conversion and space solar power. His work in geophysics aimed at development of theoretical models of atmospheres and oceans to address environmental issues, including the ocean/climate model first employed by the UN Intergovernmental Panel on Climate Change (IPCC) to assess global warming from different scenarios of fossil fuel use. His early model of the evolving CO2 greenhouse in Mars' atmosphere is also of interest today -- providing both an explanation of Mars' riverbed-like
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