Snecma pioneered electric propulsion for satellites in Europe, kicking off work in this field as early as the 1960s. Since 1993, Snecma has focused on plasma propulsion, initially developed in Russia, while designing its own Hall effect (plasma) thruster using Western technologies.
Snecma is part of International Space Technology, Inc. (ISTI), a joint venture created in 1993 with Russian specialist Fakel, Space Systems/Loral and Atlantic Research Corporation (ARC) to offer the SPT thrusters produced by Fakel in Western markets. Snecma designs and builds thruster modules based on the SPT100 thruster. Four Astrium communications satellites already in orbit are equipped with these Thruster Module Assemblies (TMA) by Snecma: Intelsat 10-02, Inmarsat 4-F1, 4-F2 and 4-F3. Each satellite is fitted with two TMAs, each comprising two SPT100 thrusters. Snecma is also developing EPTA subassemblies for the Small Geo satellite made by SSC-OHB.
Snecma has also developed, in conjunction with Fakel, its own PPS1350 plasma thruster, designed for orbital control of communications satellites. In March 2005, a PPS® 1350 propelled the European Space Agency’s Smart-1 lunar probe into observation orbit around the Moon. The Alphasat communications satellite being built by Thales Alenia Space will be equipped with four PPS1350 thrusters.
Plasma propulsion offers considerable advantages, especially for geostationary satellites and planetary probes. These thrusters use xenon gas as a propellant and electrical power from the solar panels. They offer very high efficiency, for significant weight savings over conventional chemical propulsion systems. The PPS®1350, for instance, consumes 5 to 6 times less propellant than a chemical thruster for the same mission.
Chemical thrusters
Snecma developed the 200-Newton bipropellant (MMH-N2O4) engine for attitude control and docking maneuvers on the ATV (Automated Transfer Vehicle) that ferries supplies to the International Space Station. Twenty-eight engines of this type were used on the first ATV, dubbed “Jules Verne”, during its mission to the International Space Station in 2008. The second ATV, slated for a launch at the end of 2010, is also fitted with Snecma’s 200N engines.
Because of the demanding specifications for a pulsed 200-N bipropellant engine of this type, spanning a broad operating envelope, Snecma had to carry out extensive modeling and testing. The engine is fitted with a four-chamber titanium injector, and a niobium combustion chamber cooled by a propellant film. It is also equipped with dual-solenoid valves to provide very short thrust pulses.