The thruster for the ATS-6 test consisted of two electron bombardment engines using cesium propellant. The thruster anode diameter was 8 cm, and a cesiated tungsten neutralizer was used. Beam power supply voltage was 5600 V, and the power per thruster was 0.15 kW, producing 4.5 mN thrust at a specific impulse of 2500 seconds. About 3.6 kg of propellant was carried. The longest ground test prior to launch was 2614 hours, and on ATS-6 the thruster operated for 92 hours before further testing was terminatd due to feed system flooding problems.