Optical performance of thin film, inflatable, solar concentrators for illuminating PV arrays

Inflatable technology for antennas and solar concentrators is rapidly maturing. Large inflatable paraboloids, developed for space propulsion systems and antennas are now available for ground test of power systems. Inflatable structures can potentially reduce spacecraft weight and decrease the volume required by a power system. Reflective surfaces do not require much mass so that inflatable antennas or concentrators can be very lightweight. Inflatables can also be packaged more compactly than rigid structures thereby reducing volume constraints in a faring. Therefore, we believe that space power applications could benefit from this technology. This paper includes a basic analysis of a candidate power system using an optical ray-trace code. By using a large area concentrator, it is hoped that the paraboloid concentrators for solar-thermal propulsion. This analysis will show if a uniform distribution of light can be concentrated on a photovoltaic array so that useful power might be generated. In the future, other technical challenges must be addressed. In particular, heat rejection will be a problem since then must be accomplished from the smaller area of the photovoltaic array as opposed to the area of the concentrator.