The CONTOUR spacecraft power subsystem

The Johns Hopkins University Applied Physics Laboratory (APL) has developed the CONTOUR (Comet Nucleus Tour) spacecraft for the NASA discovery satellite program. The spacecraft is an octagonal-shaped cylinder with 26.5% efficient triple-junction solar cells mounted on all eight side-panels and one top panel. The coarse solar power control is done using digital shunts while fine control is performed using six-stage sequential analog dissipative shunts with shunt dissipators mounted on the dust shield. The power system electronic provides redundant linear battery chargers and NiCd battery. NiCd battery is required to support lunch, Earth flybys and emergency conditions.