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.

Carbide-based fuel assembly includes outer structural member of ceramic matrix composite material, the interior surface of which is lined in higher temperature regions with an insulation layer of porous refractory ceramic material. A continuous insulation layer extends the length of the fuel assembly or separate insulation layer sections have a thickness increasing step-wise along the length of the fuel assembly from upper (inlet) section towards bottom (outlet) section. A fuel element positioned inward of the insulation layer and between support meshes has a fuel composition including HALEU and has the form of a plurality of individual elongated fuel bodies or one or more fuel monolith bodies containing coolant flow channels. Fuel assemblies are distributively arranged in a moderator block, with upper end of the outer structural member attached to an inlet for propellant and lower end of the outer structural member operatively interfaced with a nozzle forming a NTP reactor.

Carbide-based fuel assembly includes outer structural member of ceramic matrix composite material (e.g., SiC—SiC composite), insulation layer of porous refractory ceramic material (e.g., zirconium carbide with open-cell foam structure or fibrous zirconium carbide), and interior structural member of refractory ceramic-graphite composite material (e.g., zirconium carbide-graphite or niobium carbide-graphite). Spacer structures between various layers provide a defined and controlled spacing relationship. A fuel element bundle positioned between support meshes includes a plurality of distributively arranged fuel elements or a solid, unitary fuel element with coolant channels, each having a fuel composition including high assay, low enriched uranium (HALEU). Fuel assemblies are distributively arranged in a moderator block and the upper end of the outer structural member is attached to a metallic inlet tube for hydrogen propellant and the lower end of the outer structural member is interfaced with a support plate, forming a NTP reactor.

A space propulsion system can serve miniaturised satellites, but can be scaled easily, and includes: a combustion chamber implemented by a cylindrical container having cylindrical walls, a first end provided with at least an injection duct for a combustion agent, a fuel and/or a mixture thereof, for the injection according to a direction tangential to the cylindrical walls so as to induce a helical combustion path in the combustion chamber, a possible additional perpendicular injection duct for a fuel or a combustion agent, and an opposite end provided with a discharge duct arranged according to a direction tangential to the cylindrical walls so as to receive and direct the helical path, wherein the cylindrical walls in case have a deposition of catalytic material inside thereof, for accelerating the combustion reaction; and a supersonic nozzle, connected to the discharge duct for discharging the combustion products in the combustion chamber.

A method of replacing a module in a modular gas turbine engine having a first fan module; a first propulsor module including an engine core and a gearbox; and a first fan case module having a fan case; includes the steps of: disassembling the gas turbine engine, replacing one of the fan module, propulsor module or fan case module with a replacement fan module, a replacement propulsor module or a replacement fan case module, the replacement module, having the same configuration as the first module; and reassembling the gas turbine engine using the replacement module.

A method of replacing a module in a modular gas turbine engine having a first fan module; a first propulsor module including an engine core and a gearbox; and a first fan case module having a fan case; includes the steps of: disassembling the gas turbine engine, replacing one of the fan module, propulsor module or fan case module with a replacement fan module, a replacement propulsor module or a replacement fan case module, the replacement module, having the same configuration as the first module; and reassembling the gas turbine engine using the replacement module.

A vapor jet system to continuously jet vapors while suppressing cavitation. One vapor jet system includes a liquid storage part for separately storing two or more kinds of mutually insoluble liquids; a jet orifice; and a jet control part. Jetting the vapors is from a state where pressure in the space storing the vapors in the liquid storage part is higher than the saturated vapor pressure in any of the two or more kinds of liquids. Alternatively, a vapor jet system can include a fluid storage part storing one kind of liquid and at least one kind of inactive gas having a composition different from the liquid; a similar jet orifice; and a similar jet control part. Jetting the vapors and inactive gas(es) is (are) from a state where pressure in a vapor storing space in the fluid storage part is higher than the saturated vapor pressure in the liquid.

A vapor jet system to continuously jet vapors while suppressing cavitation. One vapor jet system includes a liquid storage part for separately storing two or more kinds of mutually insoluble liquids; a jet orifice; and a jet control part. Jetting the vapors is from a state where pressure in the space storing the vapors in the liquid storage part is higher than the saturated vapor pressure in any of the two or more kinds of liquids. Alternatively, a vapor jet system can include a fluid storage part storing one kind of liquid and at least one kind of inactive gas having a composition different from the liquid; a similar jet orifice; and a similar jet control part. Jetting the vapors and inactive gas(es) is (are) from a state where pressure in a vapor storing space in the fluid storage part is higher than the saturated vapor pressure in the liquid.

A jet engine assembly and a method of operation in which nitrogen is removed from air using a nitrogen adsorption system to create an O.sub.2-rich product which adds to the air combusted in the jet engine, thus reducing fuel usage. In addition, a nitrogen product produced by the nitrogen adsorption system is preferably used for producing greater thrust.

A jet engine assembly and a method of operation in which nitrogen is removed from air using a nitrogen adsorption system to create an O.sub.2-rich product which adds to the air combusted in the jet engine, thus reducing fuel usage. In addition, a nitrogen product produced by the nitrogen adsorption system is preferably used for producing greater thrust.