The thermosphere, ionosphere, mesosphere energetics and dynamics (TIMED) spacecraft power system

The TIMED spacecraft is a three axis stabilized nadir pointing low Earth orbit scientific satellite with one side of the spacecraft always pointing away from the Sun. The instruments fields of view, pointing accuracy, jitter requirements, anti-sun pointing of one spacecraft side and sun angle variation during the year impose special demands on the power system design. The power subsystem selected to meet the mission requirements is a peak power tracking system with a single 50 Ahr 22 cell individual pressure vessel Ni-H/sub 2/ battery. Each battery cell is bypassed by a contactor. The two driven solar array wings are populated with 5.5 mil GaAs/Ge cells. The solar power generated by each wing has a sinusoidal shape.