The thruster selected for primary propulsion on SMART-1 is the PPS-1350 developed by SNECMA. This is a stationary plasma thruster (SPT) with a chamber diameter of 100 mm, a maximum discharge power of 1.5 kW and a minimum demonstrated discharge power of 480 W. At the beginning of the SMART-1 mission, 1190 W will be available for powering the thruster, giving a nominal thrust of 68 mN at a specific impulse of 1640 seconds. The qualified lifetime of the thruster is 7000 hours at maximum power, corresponding to a total impulse of 2 x 10⁶ Ns.

Artist's impression of SMART-1's ion engine in operation.

In addition to the thruster, the electric propulsion system is composed of the following components:

• Power processing unit, which controls the electrical functions of the thruster
• Pressure regulator, which supplies gas from the storage tank to the flow control unit at the required pressure
• Remote terminal unit, which interfaces the propulsion system components to the spacecraft command and telemetry systems
• Electrical filter unit, which suppresses the conducted electromagnetic emissions produced by the discharge current
• Xenon flow control unit, which modulates the mass flow rate of gas entering the thruster
• Propellant storage tank with a volume of 49 litres, capable of storing 82 kilograms of xenon at a pressure of 150 bar
• Thruster orientation mechanism, to allow adjustment of the direction of thrust relative to the spacecraft axes
• Harness and piping connecting the various components together

Hall Effect Thrusters