IIId-2 - Operation of Solar Cells in a Space Environment

Abstract

This chapter discusses the operation of solar cells in a space environment. The first 30 years of space solar cell development focused on silicon solar cells. The concept of a tandem cell was proposed in the early days to enhance the overall efficiency. An optimized three-cell stack followed with a theoretical optimum efficiency of 37%. However, it was 40 years later before a multijunction solar cell flew in space. Today, silicon cells still fly in space, but the cell of choice is a multijunction solar cell. While commercial satellites use silicon, dual, or triple junction GaInP/GaAs/Ge, there is a marked interest in military applications of thin-film cells. NASA also has planned missions in which a large specific power (kW/kg) and lower cost would be beneficial. The advantages of thin film solar cells are their large specific power when deposited on a flexible, lightweight substrate with a suitably lightweight support structure. This chapter discusses space missions and their environments. Concepts of air mass zero spectrum, trapped radiation environment, solar flares, neutral environment, the particulate environment, and thermal environment are explained in detail.