The FAST solar array: challenging requirements, novel design

The Small Explorer (SMEX) Fast Auroral Snapshot (FAST) spacecraft was developed to investigate plasma physics of auroral phenomena at high orbital altitude. The FAST spacecraft has a variety of deployable booms with sensors on the ends and instruments that protrude from the main body of the spacecraft to collect plasma and electromagnetic field data. This requires that the plasma disturbance around the spacecraft be kept to a minimum. This requirement led to the development of a body mounted solar array with a Faraday box covering the outer surface and magnetic field cancellation circuitry to minimize this plasma disturbance. Solar array power is generated by 8225 GaAs/Ge solar cells covered by fused silica coverglasses coated with indium-tin-oxide as one component of the Faraday box. The key design features and trade studies performed for this solar array are discussed.