The development and flight history of the first generation 490N liquid apogee engine

The Liquid Apogee Engine is used to provide the thrust for apogee injection manoeuver required for the spacecraft planned mission. The Chinese unique 490N Liquid apogee engine, model FY-25, was developed by Shanghai Institute of Space Propulsion, has the features of long duration, high reliability and stable performance using storable nitrogen tetrxoide and monomethylhydrazine propellants. The thruster chamber made from NbHf10-1M niobium alloy has successfully demonstrated a nominal vacuum impulse specific of 2990N • s/kg at a nozzle area ratio of 154:1 and chamber pressure of 0.68MPa, the maximum operating temperature of 1360°C at the throat. The engine has demonstrated the capability of 84 accumulated restart and about 28 702.5 seconds accumulated burning time with single unit. In November of 1994, the engine was used on the first DFH-3 communication satellite firstly. Later, the engine was used on the other satellites, such as the Moon exploring Chang-E Satellites, BeiDou Navigation Satellites, Sinsat-2 Satellite, Nigcomsat-1 Satellite and Venesta-1 Satellite. Up to now, it has been flight qualified in 30 satellites with 100% success, including 6 DFH-4 platform and 24 DFH-3 platform satellites. The design, the characteristics, and the flight history of the mode FY-25 490N liquid apogee engine was described in detail in this paper. Particularly, in the case of some failures occurring on several satellites, the engine completed the maneuver task successfully. The development and qualification hot firing test of the next generation high performance 490N liquid apogee engine have been accomplished. The impulse specific of the next generation 490N engine is about 3090N • s/kg, the first flight product was delivered in April 2011 and will fly at the beginning of next year.