A thruster control device has an opening degree estimating section and an opening degree control section. The opening degree estimating section calculates an estimated opening degree of a valve showing a rate at which the valve is opened, based on a balance of an acting force applied to a valve element of the valve to adjust a quantity of combustion gas to be ejected from a thruster and a fluid force applied to the valve element by the ejected combustion gas. The opening degree control section determines a target opening degree based on the estimated opening degree to control the opening degree of the valve.

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.

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.

An attitude control and thrust boosting system (100) for a space launcher is disclosed, wherein the space launcher is equipped with a rocket engine (303) provided with an exhaust nozzle. The exhaust nozzle comprises a divergent portion (302) so designed as to make a supersonic gas flow exit through an exit section defined by a given angle of divergence with respect to a longitudinal axis of the rocket engine. The attitude control and thrust boosting system (100) comprises flaps (110, 111, 112, 113) that are arranged around the exit section, are shaped so as to extend the divergent portion of the exhaust nozzle, are mechanically decoupled from said exhaust nozzle and can be actuated to take different angular positions with respect to the longitudinal axis of the rocket engine. Control means (130) are also provided to receive quantities indicative of an actual attitude of the space launcher and an ambient static pressure, and to make the flaps (110,111,112,113) take a neutral angular position where the flaps (110,111,112,113) are inclined, with respect to the longitudinal axis of the rocket engine, according to an inclination angle greater than, or equal to, the given angle of divergence, in order to control the neutral angular position taken by the flaps (110,111,112,113) according to the ambient static pressure and to make one or more flaps (110,111,112,113) take an angular position different than the neutral angular position according to the actual attitude of the space launcher and to a required attitude for said space launcher.

An attitude control and thrust boosting system (100) for a space launcher is disclosed, wherein the space launcher is equipped with a rocket engine (303) provided with an exhaust nozzle. The exhaust nozzle comprises a divergent portion (302) so designed as to make a supersonic gas flow exit through an exit section defined by a given angle of divergence with respect to a longitudinal axis of the rocket engine. The attitude control and thrust boosting system (100) comprises flaps (110, 111, 112, 113) that are arranged around the exit section, are shaped so as to extend the divergent portion of the exhaust nozzle, are mechanically decoupled from said exhaust nozzle and can be actuated to take different angular positions with respect to the longitudinal axis of the rocket engine. Control means (130) are also provided to receive quantities indicative of an actual attitude of the space launcher and an ambient static pressure, and to make the flaps (110,111,112,113) take a neutral angular position where the flaps (110,111,112,113) are inclined, with respect to the longitudinal axis of the rocket engine, according to an inclination angle greater than, or equal to, the given angle of divergence, in order to control the neutral angular position taken by the flaps (110,111,112,113) according to the ambient static pressure and to make one or more flaps (110,111,112,113) take an angular position different than the neutral angular position according to the actual attitude of the space launcher and to a required attitude for said space launcher.

A rocket motor has a nozzle that is reconfigurable by erosion or ablation of the material around the throat of the nozzle. The nozzle throat has layers of materials with different erosion characteristics, with the erosion occurring so as to achieve the desired nozzle characteristics (configurations) during different parts of the fuel burn. The nozzle throat includes relatively-high-erosion material layers and relatively-low-erosion material layers, with some layers of the throat resisting erosion, while other of the layers erode or ablate relatively quickly. The relatively-low-erosion material layers may act as thermal barriers to fix the throat at relatively stable geometry for long periods of time, such as during most of the burn of different fuel segments, with the relatively-high-erosion material layers allowing rapid transition of the throat from one geometry to the next. The layers may be made by resin transfer molding (RTM).

A rocket motor has a nozzle that is reconfigurable by erosion or ablation of the material around the throat of the nozzle. The nozzle throat has layers of materials with different erosion characteristics, with the erosion occurring so as to achieve the desired nozzle characteristics (configurations) during different parts of the fuel burn. The nozzle throat includes relatively-high-erosion material layers and relatively-low-erosion material layers, with some layers of the throat resisting erosion, while other of the layers erode or ablate relatively quickly. The relatively-low-erosion material layers may act as thermal barriers to fix the throat at relatively stable geometry for long periods of time, such as during most of the burn of different fuel segments, with the relatively-high-erosion material layers allowing rapid transition of the throat from one geometry to the next. The layers may be made by resin transfer molding (RTM).

A rocket in one example includes separate chambers for storing two thrust grains: an initial thrust grain and a boost thrust grain. The initial thrust grain is stored in a first chamber and the boost thrust grain is stored in a second chamber. The initial thrust grain is ignited separately from the boost thrust grain, such as in a two-stage process where the initial thrust grain is ignited before, or at the same time as, the boost thrust grain. The initial thrust grain has a large surface area (different burn pattern) relative to the boost thrust grain, which causes the initial thrust grain to have a shorter burn time than the boost thrust grain.

A rocket in one example includes separate chambers for storing two thrust grains: an initial thrust grain and a boost thrust grain. The initial thrust grain is stored in a first chamber and the boost thrust grain is stored in a second chamber. The initial thrust grain is ignited separately from the boost thrust grain, such as in a two-stage process where the initial thrust grain is ignited before, or at the same time as, the boost thrust grain. The initial thrust grain has a large surface area (different burn pattern) relative to the boost thrust grain, which causes the initial thrust grain to have a shorter burn time than the boost thrust grain.

A system for multiple burns from a solid fuel rocket motor may extinguish rocket fuel after the rocket has been ignited. The motor may be extinguished via rapid decompression of the combustion chamber. The fuel may then be reignited by a suitable igniter, and the process of extinguishing and reigniting may be repeated, enabling multi-burn maneuvers. A decompressive extinguishing plug nozzle may extinguish solid rocket fuel after the rocket has been ignited and/or keep a rocket in a disarmed (zero thrust) state until the rocket is to be armed. The nozzle may include a plug that mostly impedes the opening of the nozzle and an outer cowl that is movable to rapidly decompress the combustion chamber. This rapid decompression extinguishes the solid rocket fuel. In some aspects, the fuel can be reignited and extinguished multiple times.