A long duration and high reliability liquid apogee engine for satellites

Abstract

The Chinese unique 490 N liquid apogee engine, Model FY-25, is described in detail in this paper. The engine, which was developed by Shanghai Institute of Space Propulsion (SISP) and used to provide thrust for apogee injection maneuver required for the telecommunication satellite, has been flight qualified for use in 6 satellites using storable nitrogen tetroxide (NTO) and monomethylhydrazine (MMH) propellants. It has the characteristics such as long operation duration, high reliability and stable performance. The thrust chamber made from NbHf10-1M niobium alloy has been successfully demonstrated with a nominal vacuum specific impulse of 3030 N s / kg at nozzle area ratio of 154:1 and chamber pressure of 0.68 MPa . The maximum operating temperature is 1360°C at the throat. The engine has demonstrated the capability of 26 accumulated restarts and about 26 110 s accumulated burning time with single unit. The investigation to improve the specific impulse, including adoption of secondary combustion assembly, Re/Ir and C/SiC composite materials combustion chamber is described in detail. Both the rhenium/iridium and the C/SiC are advanced materials that can withstand higher temperature than the conventional NbHf10-1M niobium alloy.