Photovoltaic solar arrays are the principal means of converting solar energy to electrical energy for satellites. Array configurations depend on the spacecraft stabilization concept, orbit, and power requirements. The current generation of communication satellites are spin-stabilized in synchronous equatorial orbits; their arrays are spinning cylinders. As satellite power requirements increase, it is expected that the trend will be toward extendible arrays on three-axis stabilized spacecraft. The single crystal silicon cell is the basic building block of today's solar arrays and is expected to be for some time, although cadmium sulfide thin film solar cells may offer several advantages once their development is completed. Several of the considerations in the design of solar arrays are discussed: radiation effects on solar cells, substrates, selection of array voltage, analysis of shadows, and overall performance.