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The role of radiation hard solar cells in minimizing the costs of global satellite communications systemsAn analysis embodied in a PC computer program is presented which quantitatively demonstrates how the availability of radiation hard solar cells can minimize the cost of a global satellite communication system. The chief distinction between the currently proposed systems, such as Iridium Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation within the earth's radiation belts can reduce the total system cost by as much as a factor of two, so long as radiation hard components including solar cells, can be used. A detailed evaluation of several types of planar solar cells is given, including commercially available Si and GaAs/Ge cells, and InP/Si cells which are under development. The computer program calculates the end of life (EOL) power density of solar arrays taking into account the cell geometry, coverglass thickness, support frame, electrical interconnects, etc. The EOL power density can be determined for any altitude from low earth orbit (LEO) to geosynchronous (GEO) and for equatorial to polar planes of inclination. The mission duration can be varied over the entire range planned for the proposed satellite systems. An algorithm is included in the program for determining the degradation of cell efficiency for different cell technologies due to proton and electron irradiation. The program can be used to determine the optimum configuration for any cell technology for a particular orbit and for a specified mission life. Several examples of applying the program are presented, in which it is shown that the EOL power density of different technologies can vary by an order of magnitude for certain missions. Therefore, although a relatively radiation soft technology can be made to provide the required EOL power by simply increasing the size of the array, the impact on the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global coverage systems range from $1 Billion to $9 Billion, the availability of radiation hard solar cells could make a decisive difference in the selection of a particular constellation architecture.
Document ID
19960007883
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Summers, Geoffrey P.
(Naval Research Lab. Washington, DC, United States)
Walters, Robert J.
(Naval Research Lab. Washington, DC, United States)
Messenger, Scott R.
(SFA, Inc. Landover, MD., United States)
Burke, Edward A.
(Burke, Edward A., Woburn MA., United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1995
Publication Information
Publication: NASA. Lewis Research Center, Proceedings of the 14th Space Photovoltaic Research and Technology Conference (SPRAT 14)
Subject Category
Energy Production And Conversion
Accession Number
96N15049
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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