The STEREO Spacecrafts Power System

The Solar TErrestrial RElations Observatory (STEREO) observatories are two NASA spacecrafts that will be orbiting the Sun close to Earth’s orbit with one spacecraft “ahead” of the Earth and the second “behind” the Earth for a two year mission. STEREO launch is planned for July 2006. The two spacecraft power systems are nearly identical. Each spacecraft has two deployed fixed solar array wings. Each wing has two panels. A peak power tracking system has been selected. A single 23AHr, eleven-cell Common Pressure Vessel NiH2 battery is used. Heritage designs were used to reduce cost , schedule risks and to insure mission success.