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.

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.

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.

A hot-gas-generating apparatus for reacting a propellant comprises a combustion chamber, at least one injector that is arranged upstream of the combustion chamber and can be closed, on the combustion chamber side, to the propellant, electrodes being integrated in said injector, and at least one supply line for the propellant. In this context, the propellant is a monopropellant and a substantially water-free ionic solution having low vapor pressure, preferably with a residual water content of less than five percent by mass, which is capable of self-sustaining combustion at a given combustion chamber pressure, and the electrodes have at least two electrodes of opposite polarity which are suitable for electrically igniting the propellant by means of a flow of current through the propellant when this propellant flows between the opposite-polarity electrodes.

A hot-gas-generating apparatus for reacting a propellant comprises a combustion chamber, at least one injector that is arranged upstream of the combustion chamber and can be closed, on the combustion chamber side, to the propellant, electrodes being integrated in said injector, and at least one supply line for the propellant. In this context, the propellant is a monopropellant and a substantially water-free ionic solution having low vapor pressure, preferably with a residual water content of less than five percent by mass, which is capable of self-sustaining combustion at a given combustion chamber pressure, and the electrodes have at least two electrodes of opposite polarity which are suitable for electrically igniting the propellant by means of a flow of current through the propellant when this propellant flows between the opposite-polarity electrodes.

An injection apparatus for a rocket engine comprises an injection plate which delimits a combustion chamber upstream. The injection apparatus further comprises a plurality of coaxial injection elements distributed in the injection plate, each of which injection elements forms an inner outlet opening, delimited by a central sleeve body, for a first propellant component and an outer outlet opening for a second propellant component. The outer outlet opening is formed between the central sleeve body and a wall section which surrounds the central sleeve body in an annular manner. At least in a partial number of the injection elements, the central sleeve body projects from the wall section in the direction towards the combustion chamber. In particular, the central sleeve body projects relative to the injection plate into the combustion chamber.

An injection apparatus for a rocket engine comprises an injection plate which delimits a combustion chamber upstream. The injection apparatus further comprises a plurality of coaxial injection elements distributed in the injection plate, each of which injection elements forms an inner outlet opening, delimited by a central sleeve body, for a first propellant component and an outer outlet opening for a second propellant component. The outer outlet opening is formed between the central sleeve body and a wall section which surrounds the central sleeve body in an annular manner. At least in a partial number of the injection elements, the central sleeve body projects from the wall section in the direction towards the combustion chamber. In particular, the central sleeve body projects relative to the injection plate into the combustion chamber.

A method of starting combustion of a space vehicle engine, the method comprising igniting a propellant tank heater (25); once the heater (25) has reached stable conditions, pressurizing a first tank (23) containing the first propellant and a second tank (24) containing a second propellant, and in parallel filling respectively a first igniter tank (13) with the first propellant in gaseous form and a second igniter tank (14) with the second propellant in gaseous form until ignition thresholds values of temperature (T.sub.13, T.sub.14) and of pressure (P.sub.13, P.sub.14) have been reached; and injecting the first and second propellants in gaseous form contained in the first and second igniter tanks (13 and 14) into an igniter (12) of the engine, so as to initiate combustion.

Power device based on alkali-water reaction, having a reaction chamber to carry out a chemical reaction between water and alkali element, having an exhaust nozzle to exhaust the reaction products generated in the reaction chamber, with a siphon tube connected to the exhaust nozzle, a nozzle shutter plate sealing the exhaust nozzle, and an external pressure inlet. The device has a water reservoir to store transfer water to the reaction chamber and an alkali reservoir to store and transfer an alkali element to the reaction chamber, and transfer device connecting the reaction chamber to both reservoirs to transmit the pressure generated in reaction chamber by part of the reaction products to the reservoirs, providing the transfer of water and alkali element from both reservoirs to the reaction chamber.

Power device based on alkali-water reaction, having a reaction chamber to carry out a chemical reaction between water and alkali element, having an exhaust nozzle to exhaust the reaction products generated in the reaction chamber, with a siphon tube connected to the exhaust nozzle, a nozzle shutter plate sealing the exhaust nozzle, and an external pressure inlet. The device has a water reservoir to store transfer water to the reaction chamber and an alkali reservoir to store and transfer an alkali element to the reaction chamber, and transfer device connecting the reaction chamber to both reservoirs to transmit the pressure generated in reaction chamber by part of the reaction products to the reservoirs, providing the transfer of water and alkali element from both reservoirs to the reaction chamber.