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I "asked an expert" about SPSS and here is what they wrote back.


Energy Efficiency and Renewable Energy Clearinghouse (EREC)
PO Box 3048, Merrifield, VA 22116
Phone: in USA: 1-800-363-3732
Re: 'Has any research (possibly Russian) gone into direct use of solar radiation outside the Earth atmosphere? (concentration and transmission to supplant Earth-based resources, renewable or not)'

Dear Paul Suckow:

Thank you for your inquiry (see copy above) to Ask an Energy Expert.

We have the info brief and lists of resources below (scroll down) which may be helpful.

For your information, there are numerous factsheets, information briefs, reading lists, and referrals on a wide variety of renewable energy and energy efficiency topics available on the World Wide Web at: *

For quick access to our factsheets, go to URL:  *  [*moved:  see Links]

We hope this helps, and on behalf of the US Department of Energy thank you for your interest in energy efficiency and renewable energy. Please contact us again if we can be of additional assistance.

Sincerely, Paul Hesse

The following information was prepared by the staff of the EREC:

Solar Power Satellites

The feasibility of solar power stations orbiting the Earth and sending power to the surface, was investigated during the 1970's energy crisis. The National Aeronautics and Space Administration (NASA) and the U.S. Department of Energy (DOE) studied the concept of the Solar Power Satellites System (SPSS), which consisted of placing about 60 satellites containing large photovoltaic arrays in stationary orbits above the earth. Each satellite would have a matching receiving rectifying antenna (rectenna) on the ground. The satellites would have transmitted a fixed microwave beam to the ground station. The microwave transmission system envisioned by NASA and DOE would have had three aspects:

  1. the conversion of direct current (DC) power (from the photovoltaic cells on the satellites) to microwave power.
  2. the formation and control of microwave beams aimed precisely at fixed locations on the earth's surface.
  3. the collection of the microwave energy and its conversion into DC electrical energy at the earth's surface.

Each SPSS would have been massive, measuring 6.5 miles (10.5 kilometers[km]) long and 3.3 miles (5.3 km) wide, or 21 square miles (55.7 square kilometers) in area. The surface of each satellite would have been covered with 400 million solar cells.

Because of their size, the satellites would have been constructed in space. The plan envisioned sending small segments of the satellites into space using the Space Shuttle. The materials would have been stored at work stations in low earth orbit, and then towed to the assembly point by a purpose-built "space tug."

Cost was the major obstacle to development of the SPSS. When the NASA-DOE report was completed in 1979, the estimated cost for building a prototype was $74 billion. Construction of an SPSS system would have taken about 30 years to complete. At the time, the United States did not appropriate funds to begin construction, but other countries, including Russia, are currently exploring the concept.

The following publications contain additional information on solar power satellites. This bibliography was reviewed in April 2000.
  • Leadership and America's Future in Space, S. Ride, NASA, 1987. Available from Center for Aerospace Information, 7121 Standard Drive, Hanover, Maryland 21076-1230: Phone: (301) 621-0390; Fax: (301) 621-0134. 64 pp., Report No. # NASA-TM-89638.
    Personal note: I ordered this document, what CAI sent was very poor photocopy reproduction of the original report. Not worth the expense and not recommended.
  • Pioneering the Space Frontier: The Report of the National Commission on Space, Bantam Books, New York, NY, 1986. 211 pp. Out of print, check your local library for availability.
  • "Renewed Interest in Space Solar Power," T. Moore, EPRI Journal, (25:1), pp. 6-17, Spring 2000.


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