Solar thermal propulsion engine and process of its operation

RU patent № 2197630

The solar thermal propulsion engine (STPE) can be used in propulsion systems of orbital transfer vehicles. The STPE with an electrothermal heat accumulator-exchanger energized by the solar battery, comprising liquid hydrogen and oxygen tanks, hydrogen and oxygen feed systems and an engine chamber, is fitted with a compressor and a gaseous hydrogen receiver, an oxygen gasifier and a gaseous oxygen receiver with an electric preheater. Besides, the STPE can have hydrogen electrothermal thrusters (ETT) of low power as part of its structure.
The main feature of STPE operation, which operates in modes with combustion of "cold" or "hot" hydrogen, also on "hot" hydrogen without its combustion, is that the engine is started and operated in all modes by supplying gaseous-phase oxygen and hydrogen to the engine chamber, and the hydrogen, which has evaporated in the tank owing to external heat inputs, is pumped out of the tank to the hydrogen receiver by a compressor and is used for engine startings. In the process of engine operation the hydrogen can be fed to the engine chamber from the receiver together with the hydrogen which is drawn from the tank in the liquid state, and before feeding it to the engine chamber it is passed in succession through the cooling passage of engine chamber, the oxygen gasifier and the heat accumulator-exchanger.
Such STPE device and the process of its operation with the high effectiveness of application as part of orbital transfer vehicles provide high combustion completeness and small losses of specific impulse, simple and reliable multistep firings in zero gravity, effective use of hydrogen vapours and minimization of pressure in the hydrogen tank, and with ETT in the STPE structure - a high efficiency of the use of solar energy for heating the hydrogen and shortening of the transfer time.