In the early 1990s, Lockheed Martin utilized a new thruster, the hydrazine arcjet for North-South station keeping (NSSK) on its geostationary orbit satellites. The early R&D (through preflight qualification) on the hydrazine arcet was done at NASA Glenn
Research Center. The current production arcjet thrusters are manufactured by Aerojet Redmond. The Lockheed Martin series 7000
satellites use the Aerojet MR 509 hydrazine arcjet system (1.8 kW power level, Isp of 502 sec). The archet continues to evolve with the
latest Lockheed satellite bus, the A2100 satellites, which utilize the MR-510 arcjet system (2.2 kW, 582-sec nominal Isp thrusters) for
NSSK. Again, the archet thruster takes advantage of the higher satellite power available to substantially increase the performance
over catalytic hydrazine (Isp = 225 sec to Isp = 570 to 600 sec).