Attitude control
The body is constructed largely of composites. Propulsion is by a hydrazine monopropellant system, containing 544 kg of fuel in four exposed tanks. The titanium tanks were charged with gas to 24 bar (2.4 MPa) at 30 °C, and have tank diaphragms. Attitude control is via a star tracker, multiple Sun sensors, and multiple momentum wheels. The dual solar arrays, spanning 16 meters when deployed and producing 2.4 kW BoL, are backed up by dual nickel-cadmium battery sets.