Nonimaging optical design for microconcentrating photovoltaics in space

Rapid growth in the number of Earth-orbiting satellites with electric propulsion as well as plans for colonizing the Moon will dramatically increase the demand for solar photovoltaic (PV) power in space. Most of these missions will be commercially-driven, heightening the need for PV systems that are more compact, lower-mass, more efficient, reliable, and affordable than ever before. In this talk, I will describe how microscale PV cells integrated with ultracompact concentrating optics offer a new opportunity to improve performance and reduce cost without sacrificing reliability. I will overview the unique constraints imposed on nonimaging concentrator design by operation in space and describe an experimental prototype <2 mm thick that achieves 26% power conversion efficiency at a geometric gain of 18x with a specific power >100 W/kg and an acceptance angle of nearly ±10°.