The thruster for the Snapshot test was a contact ionization engine using cesium propellant. The thruster anode diameter was 5 cm, and a barium-coated wire filament neutralizer was used. Beam power supply voltage was 4500 V, and the power per thruster was 0.4 kW, producing 8.5 mN thrust at a specific impulse of 5100 seconds. The Snapshot engine operated in space stably for about an hour, but continuous arcing at the high voltage terminals induced severe electromagnetic interference in other spacecraft systems.