A variable flow area injector for a liquid rocket engine. The injector has a poppet with a variable outer width portion and a housing with a variable inner width portion. An annular flow path is defined between the variable width portions. Increased throttling of the engine passively increases the annular flow area of the injector by forcing the poppet in a distal direction. Decreased throttling allows a restoring spring to move the poppet in a proximal direction to decrease the annular flow area. A bellows can be included to dampen movement of the poppet. The bellows may be in a propellant-filled cavity separate from the main propellant flow path and have a series of openings through which the separate propellant flows.

Rocket propulsion systems and associated methods are disclosed. A representative system includes a combustion chamber having an inwardly-facing chamber wall enclosing a combustion zone. The chamber has a generally spherical shape and is exposed to the combustion zone. A propellant injector is coupled to the combustion chamber and has at least one fuel injector nozzle positioned to direct a flow of cooling fuel radially outwardly along the inwardly-facing chamber wall. In addition to or in lieu of the foregoing features, the injector can include an oxidizer piston and a fuel piston that deliver oxidizer and fuel, respectively, to the combustion chamber, in a sequenced manner so that the oxidizer is introduced prior to the fuel.

According to one contemplated embodiment of the rocket engine invention, water is first pumped from a water tank through a rocket nozzle cooling heat exchanger wherein it is evaporated into said superheated steam. A generator supplies electricity to an electrolyzer that electrolyzes superheated steam into gaseous hydrogen and gaseous oxygen. The gaseous hydrogen and gaseous oxygen is employed for forming an annular curtain of secondary combustion in a divergent rocket engine. The secondary combustion gas surrounds a central thrust of combustion gas produced in an upstream combustion chamber by a primary injection of hydrogen/oxygen supplied from a liquid hydrogen tank and liquid oxygen tank. The rocket liquid hydrogen tank and liquid oxygen tank are pressurized by gaseous hydrogen and gaseous oxygen generated by the electrolyzer.

According to one contemplated embodiment of the rocket engine invention, water is first pumped from a water tank through a rocket nozzle cooling heat exchanger wherein it is evaporated into said superheated steam. A generator supplies electricity to an electrolyzer that electrolyzes superheated steam into gaseous hydrogen and gaseous oxygen. The gaseous hydrogen and gaseous oxygen is employed for forming an annular curtain of secondary combustion in a divergent rocket engine. The secondary combustion gas surrounds a central thrust of combustion gas produced in an upstream combustion chamber by a primary injection of hydrogen/oxygen supplied from a liquid hydrogen tank and liquid oxygen tank. The rocket liquid hydrogen tank and liquid oxygen tank are pressurized by gaseous hydrogen and gaseous oxygen generated by the electrolyzer.

A method for managing propellant in a spacecraft is disclosed. The method includes storing liquid propellant in a tank under an operating pressure controlled using a product of chemical decomposition of the propellant. The method may include transferring the liquid propellant out of the tank and chemically decomposing a portion of it using, for example electrolysis. Thus generated one or more gas components may be introduced to the tank to control the operating pressure in the tank.

A high density, generally recognized as safe, hybrid rocket motor is described, having a density-specific impulse similar to a solid rocket motor, with good performance approaching or equal to a liquid rocket motor. These high density hybrid motors resolve the packaging efficiency/effectiveness problems limiting the application of safe, low cost hybrid motor technology.

A monopropellant rocket thruster includes a thruster, a pump, a decomposition catalyst, and an igniter. The thruster housing includes a reaction chamber and a divergent nozzle. The pump, coupled to the thruster housing, is operable to pump a monopropellant liquid into an inlet of the reaction chamber. The decomposition catalyst, located near the inlet between the pump and the reaction chamber, is configured to decompose at least one component of the monopropellant liquid into a mixture of liquid and gas in an exothermic reaction. The igniter is disposed at an outlet of the reaction chamber, such that the igniter ignites the mixture of liquid and gas for producing expanding gas into the divergent nozzle.

A monopropellant rocket thruster includes a thruster, a pump, a decomposition catalyst, and an igniter. The thruster housing includes a reaction chamber and a divergent nozzle. The pump, coupled to the thruster housing, is operable to pump a monopropellant liquid into an inlet of the reaction chamber. The decomposition catalyst, located near the inlet between the pump and the reaction chamber, is configured to decompose at least one component of the monopropellant liquid into a mixture of liquid and gas in an exothermic reaction. The igniter is disposed at an outlet of the reaction chamber, such that the igniter ignites the mixture of liquid and gas for producing expanding gas into the divergent nozzle.

A cryogenic engine for a space apparatus is provided. The cryogenic engine includes an injector body, a thrust chamber, and a spark plug, where the injector body is provided therein with an accommodating space; the spark plug is provided on one side of the injector body, and an electrode provided on the spark plug extends into the accommodating space; the thrust chamber is provided on the other side of the injector body and is communicated with the accommodating space; the injector body is provided with a combustion improver flow channel and a combustible agent flow channel; and the combustion improver flow channel and combustible agent flow channel are connected with the accommodating space.

A turbojet engine capable of operation in an Air Turbo Rocket (ATR) mode includes a compressor, a rotatable turbine wheel comprising turbine blades, a non-rotating guide vane ring comprising guide vanes, a turbine shaft configured to power said compressor, a combustor, a gas generator, and a main combustor. The main combustor is configured to combust hot, fuel rich gas from the gas generator in air compressed by the compressor. Hot, fuel rich gas from the gas generator is directed towards the turbine blades by a directing means.