 The communications system included the high-gain antenna and an omnidirectional medium-gain antenna and two transmitters at approximately 960 MHz, one with 0.25 W power output and the other with 3 W power output.Power was to be furnished by 8680 solar cells on the two panels, a 53.5 kg silver-zinc battery, and smaller batteries on some of the experiments.Attitude control was provided by a solid state timing controller, Sun and Earth sensors, gyroscopes, and pitch and roll jets.