7-4. Central-station Electric Power for Spacecraft JERRY GREY & LUCIEN DESCHAMPS Summary Central-station electric power for spacecraft has been explored conceptually for over two decades as a solution to the economic delivery of high power levels over long periods of time. However, all spacecraft designs to date have been based on the use of onboard supplies—solar, nuclear, and chemical—because the total space power demand has not yet reached the levels at which dedicated space power depots would be economically viable. Nevertheless, the growth in projected power demand for the next several decades could warrant the use of such dedicated space-based powerplants. This paper examines and assesses the various technological options for space power generation and transmission and the system considerations associated with the space-based centralpower-station concept. Space Power Generation Space power requirements to date have been met by five generic technologies: photovoltaic arrays, nuclear reactors used with direct conversion devices, radioisotope generators employing direct conversion devices, chemical fuel cells, and chemical batteries. Of these, only photovoltaics, nuclear reactors, and fuel cells are prospective candidates for the power levels that would be economically viable for central-station space powerplants. Other prospective candidates that have not yet seen space service are solar thermal power systems, nuclear reactors used with dynamic power conversion systems, various forms of chemically powered generators, and high-density energy storage devices (for peak loading requirements and solar-panel eclipse periods). Some of these energy sources can be used with a variety of power conversion subsystems, power conditioning devices, radiator designs, and power transmission mechanisms. Energy Sources Solar. All current operational spacecraft solar power systems employ single-crystal silicon photovoltaic cells ranging in size from 2 X 2 cm to 6 X 6 cm, mounted in fixed or deploy able arrays able to provide up to 6 kWe peak power. All such systems employ chemical batteries (generally nickel-cadmium) to store energy for eclipse periods. The batteries are charged by the photovoltaic arrays. The desired system voltage is obtained by series-connecting the arrays and the batteries. Production capability now exists in Japan (Mitsubishi Electric) and the USA (Applied Solar Energy Corporation) for gallium arsenide (GaAs) cells, manufactured Jerry Grey, Consultant, USA and Lucien Deschamps, Electricite de France. Paper number IAF-ICOSP89-7-4.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==