 The telemetry system aboard the spacecraft, consisting of two 960 MHz transmitters, one at 3 W power output and the other at 50 mW power output, the high-gain antenna, and an omnidirectional antenna.White paint, gold and chrome plating, and a silvered plastic sheet encasing the retrorocket furnished thermal control.Because heat sterilization was suspected to have caused the malfunction of Ranger 3's computer, this procedure was dropped on Ranger 4.