Advanced space photovoltaic technology: applications to telecommunication systems

For nearly two decades, most NASA and commercial space power systems were typically in the 1 to 2 kilowatt range. Now, however, the demand for more power per unit mass and area of satellite solar arrays is rising dramatically, driven entirely by the telecommunications industry and some US Military applications. Commercial satellites with power system capabilities exceeding 10 kilowatts have already been launched, and hundreds more are in the planning stages. At the same time, however, NASA mission programs are striving for smaller, more specialized spacecraft which can still achieve complex mission objectives, but at lower total mission cost. These apparently divergent sets of requirements are surprisingly synergistic: both place a high priority on developing power systems with high efficiency, low mass and long life in the space environment. Key elements of the near term NASA advanced technology program include (1) development and eventual commercial production of multibandgap (MBG) solar cells with air mass zero (AM0) efficiencies approaching 30%; and (2) commercial availability of a night qualified concentrator solar array with superior lifetime and lower cost than conventional planar solar arrays. For the far term, the program is focussed on development of ultra lightweight, thin film solar arrays. The potential impact of all these technologies on telecommunication satellites is discussed.