Electric propulsion (EP) is nowadays a mature technology used on board space vehicles. In comparison with chemical thrusters, electric thrusters can advantageously accelerate propellant at a high exhaust speed. The corresponding propellant mass saving makes essential the utilization of electric thrusters for low thrust and long duration missions. Different types of EP devices have been developed for covering a large variety of maneuvers and mission requirements. To date, EP appears as a solid candidate for future manned missions. Research and development programs about EP standard technologies and new concepts are still ongoing in Europe, Russia, United States and Japan to fulfil future needs.