A propulsion system for a spacecraft includes at least one chemical propulsion engine, at least one electrical propulsion engine, and a propellant feed system that includes a propellant supply system including at least one tank to store a common propellant. The propellant supply system is configured to deliver a controlled flow of the common propellant to both the chemical propulsion engine and the electrical propulsion engine. Also disclosed is the use of a common propellant in a spacecraft and a method of providing a common propellant to an electrical and a chemical propulsion engine.

A heat exchanger which may be used in an engine, such as a vehicle engine for an aircraft or orbital launch vehicle. is provided. The heat exchanger may be configured as generally drum-shaped with a multitude of spiral sections, each containing numerous small diameter tubes. The spiral sections may spiral inside one another. The heat exchanger may include a support structure with a plurality of mutually axially spaced hoop supports, and may incorporate an intermediate header. The heat exchanger may incorporate recycling of methanol or other antifreeze used to prevent blocking of the heat exchanger due to frost or ice formation.

A method for correcting non-rigid thin-walled tubular elements having geometric deficiencies, wherein, following correction, the tubular elements may perform over a wide range of pressure and temperatures, for example as a rocket motor beaker, from about −70 C to about 1000 C. Correction is required to remove asperities, maximize cylindricity, squaring a forward end wall and a rearward end wall, so that the forward end wall of the tube product may be fitted, bonded and sealed to a circular planar element using a labyrinth-joint closure. The method provides uniformity so that both the tubular elements and the circular planar elements are interchangeably uniform in size, shape and performance, and may be readily assembled into non-rigid thin-walled tube products.

A method of controlling a multi-engine bay in which the following steps are performed: a) controlling the bay so that it delivers desired thrust and each engine is operated in compliance with a set of operating limits for the engine; b) periodically evaluating a level of damage for each of the engines, the level of damage of an engine being information representative of a probability of the engine failing; c) for each engine, periodically evaluating whether its level of damage exceeds a predetermined value; and d) if the level of damage of an engine, referred to as a “damaged” engine, exceeds a predetermined value, modifying at least one operating limit of the damaged engine so that the rate of damage of the damaged engine is less than a predetermined maximum rate of engine damage.

A rocket fueling system includes an insulated jacket configured to removably couple to at least a portion of a rocket and form an enclosed space between the insulated jacket and the at least the portion of the rocket. The rocket fueling system also includes a cryogen inlet in the insulated jacket. The cryogen inlet is configured to receive a cryogen into an interior chamber of the insulated jacket. The rocket fueling system further includes a cryogen outlet in the insulated jacket. The cryogen outlet is configured to provide the cryogen from the interior chamber in the insulated jacket to the at least the portion of the rocket in the enclosed space. The rocket fueling system still further includes a gas outlet in the insulated jacket configured to exhaust the cryogen from the enclosed space, and a flammable gas sensor configured to detect a flammable gas at the gas outlet.

A rocket fueling system includes an insulated jacket configured to removably couple to at least a portion of a rocket and form an enclosed space between the insulated jacket and the at least the portion of the rocket. The rocket fueling system also includes a cryogen inlet in the insulated jacket. The cryogen inlet is configured to receive a cryogen into an interior chamber of the insulated jacket. The rocket fueling system further includes a cryogen outlet in the insulated jacket. The cryogen outlet is configured to provide the cryogen from the interior chamber in the insulated jacket to the at least the portion of the rocket in the enclosed space. The rocket fueling system still further includes a gas outlet in the insulated jacket configured to exhaust the cryogen from the enclosed space, and a flammable gas sensor configured to detect a flammable gas at the gas outlet.

An emergency landing apparatus for an aircraft and a method of operating the emergency landing apparatus is provided. The emergency landing apparatus comprises: one or more rocket motors arranged to eject efflux in order to provide upwards thrust to control descent of the aircraft during emergency landing of the aircraft; and control circuitry configured to: cause the one or more rocket motors to eject efflux and provide upwards thrust to control descent of the aircraft during emergency landing of the aircraft; and cause redirection of the efflux ejected by the one or more rocket motors, during the emergency landing of the aircraft, in order to reduce the upwards thrust provided by the one or more rocket motors.

A power module includes a turbo-generator with a propellant selector valve, a stored energy module connected to the propellant selector valve, and bleed air conduit. The bleed air conduit is connected to the propellant selector valve, wherein the propellant selector valve has a first position, wherein the stored energy tank is in fluid communication with the turbo-generator, and a second position, wherein the bleed air conduit is in fluid communication with the turbo-generator. Vehicles and methods of generating electrical power are also described.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer and an organically modified silicon dioxide preceramic polymer. A ceramic material comprising a reaction product of the polycarbosilane preceramic polymer and organically modified silicon dioxide preceramic polymer is also described. Articles comprising the ceramic material are also described, as are methods of forming the preceramic resin formulation and the ceramic material.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer and an organically modified silicon dioxide preceramic polymer. A ceramic material comprising a reaction product of the polycarbosilane preceramic polymer and organically modified silicon dioxide preceramic polymer is also described. Articles comprising the ceramic material are also described, as are methods of forming the preceramic resin formulation and the ceramic material.