Electric thrusters are much more efficient than chemical drives in controlling the orbit and attitude of a satellite. Specific impulse is the yardstick of efficiency. A high specific impulse reduces fuel consumption and prolongs the duration of a mission. Powered by ionised xenon gas, the high-efficiency multi-stage plasma (HEMP) thruster delivers a specific impulse that is five times that of even the best chemical drives. A highly efficient power supply and control unit (PSCU) supplies high-voltage power to four thrusters. In 2014, a small geostationary satellite (SmallGEO) will be launched to demonstrate in orbit for the first time that new technologies are capable of significantly reducing the operating cost of telecommunication satellites. The HEMP thrusters, their power supply, the xenon gas flow controller, and other components will form a HEMP thruster assembly (HTA) that will be integrated in the SmallGeo satellite. The HTA project was commissioned by DLR's Space Administration.