A combustion chamber suitable in particular for use in a rocket engine comprises a combustion space, a first wall enclosing the combustion space and cooling duct fins, which extend from a surface of the first wall and separate adjacent cooling ducts from one another. At least one of the cooling duct fins has at its end facing away from the surface of the first wall a bent section, which at least partially covers a cooling duct adjacent to the cooling duct fin.

A photonic reflector device includes a first layer, a second layer, and a third layer. The first layer, which functions as a retro-reflector, is formed of a first material contacting a second material and having a non-planar interface therebetween. The second layer, which functions as a photonic crystal, includes third and fourth materials that have different refractive indices from one another and are configured such that the second layer has a periodic optical potential along at least one dimension. The third layer, which functions as a Lambertian scatterer, includes a plurality of inclusions in a first matrix material. In combination, the layers may be optimized to synergistically reflect targeted wavelengths and/or polarizations of light.

To provide an ejector for a rocket engine in which an engine nozzle body having a simpler structure can be used. A hydrogen ejector 10 for a rocket engine comprises an engine nozzle body 12 for ejecting hydrogen gas and an ejection unit 14 for ejecting hydrogen gas while controlling the temperature of the hydrogen gas within a temperature range in which a material constituting the engine nozzle body 12 through which the hydrogen gas flows can maintain its strength. The temperature range is 500° C. to 1000° C. The hydrogen gas comprises hydrogen gas generated by incomplete combustion during a combustion reaction between liquid hydrogen and liquid oxygen.

To provide an ejector for a rocket engine in which an engine nozzle body having a simpler structure can be used. A hydrogen ejector 10 for a rocket engine comprises an engine nozzle body 12 for ejecting hydrogen gas and an ejection unit 14 for ejecting hydrogen gas while controlling the temperature of the hydrogen gas within a temperature range in which a material constituting the engine nozzle body 12 through which the hydrogen gas flows can maintain its strength. The temperature range is 500° C. to 1000° C. The hydrogen gas comprises hydrogen gas generated by incomplete combustion during a combustion reaction between liquid hydrogen and liquid oxygen.

An integrated propulsion system for hybrid rockets includes an oxidizer tank, a rocket engine, a pressurization device, a pressurization device and an oxidizer pipe and valve unit. The rocket engine is disposed within the oxidizer tank partially and located on a first side of the oxidizer tank. The pressurization device is disposed, at least in part, within the oxidizer tank, is located on a second side of the oxidizer tank opposite to the first side of the oxidizer tank, and is configured to regulate an overall pressure level within the oxidizer tank. The oxidizer pipe and valve unit is connected to the oxidizer tank and the rocket engine, and is configured to control feeding of an oxidizer from the oxidizer tank into the rocket engine.

An integrated propulsion system for hybrid rockets includes an oxidizer tank, a rocket engine, a pressurization device, a pressurization device and an oxidizer pipe and valve unit. The rocket engine is disposed within the oxidizer tank partially and located on a first side of the oxidizer tank. The pressurization device is disposed, at least in part, within the oxidizer tank, is located on a second side of the oxidizer tank opposite to the first side of the oxidizer tank, and is configured to regulate an overall pressure level within the oxidizer tank. The oxidizer pipe and valve unit is connected to the oxidizer tank and the rocket engine, and is configured to control feeding of an oxidizer from the oxidizer tank into the rocket engine.

A hybrid propulsion unit, for a space vehicle or rocket, includes an external body defining a combustion chamber configured to receive a block of solid propellant, a pressurized reservoir configured to receive a liquid propellant, and a nozzle to eject the combustion gases produced by the reaction of the propellants. The pressurized reservoir being placed inside the external body, surrounded by the block of solid propellant. The propulsion unit further includes a plurality of liquid-propellant injectors disposed axially between parts of the solid propellant to improve the efficacy of the combustion. A space vehicle, of the launch vehicle type, equipped with such hybrid propulsion unit.

A hybrid propulsion unit, for a space vehicle or rocket, includes an external body defining a combustion chamber configured to receive a block of solid propellant, a pressurized reservoir configured to receive a liquid propellant, and a nozzle to eject the combustion gases produced by the reaction of the propellants. The pressurized reservoir being placed inside the external body, surrounded by the block of solid propellant. The propulsion unit further includes a plurality of liquid-propellant injectors disposed axially between parts of the solid propellant to improve the efficacy of the combustion. A space vehicle, of the launch vehicle type, equipped with such hybrid propulsion unit.

A photonic reflector device includes a first layer, a second layer, and a third layer. The first layer, which functions as a retro-reflector, is formed of a first material contacting a second material and having a non-planar interface therebetween. The second layer, which functions as a photonic crystal, includes third and fourth materials that have different refractive indices from one another and are configured such that the second layer has a periodic optical potential along at least one dimension. The third layer, which functions as a Lambertian scatterer, includes a plurality of inclusions in a first matrix material. In combination, the layers may be optimized to synergistically reflect targeted wavelengths and/or polarizations of light.

A hybrid metal composite (HMC) structure comprises tiers comprising fiber composite material structures, and additional tiers longitudinally adjacent one or more of the tiers and comprising perforated metallic structures and additional fiber composite material structures laterally adjacent the perforated metallic structures. Methods of forming an HMC structure, and related rocket motors and multi-stage rocket motor assemblies are also disclosed.