Method and apparatus for controlling pressure in a pressure vessel. A plurality of valves between a pressure source and a pressure vessel can be selectively opened or turned off, singularly or in combinations, to control pressure in the pressure vessel. A maximum pressure threshold and a minimum pressure threshold can be established based on operating considerations of the pressure vessel. One or more of the valves can be turned on when the pressure in the pressure vessel reaches the minimum pressure threshold. One or more of the valves can be turned off when the pressure in the pressure vessel reaches the maximum pressure threshold.

Method and apparatus for controlling pressure in a pressure vessel. A plurality of valves between a pressure source and a pressure vessel can be selectively opened or turned off, singularly or in combinations, to control pressure in the pressure vessel. A maximum pressure threshold and a minimum pressure threshold can be established based on operating considerations of the pressure vessel. One or more of the valves can be turned on when the pressure in the pressure vessel reaches the minimum pressure threshold. One or more of the valves can be turned off when the pressure in the pressure vessel reaches the maximum pressure threshold.

Provided herein are various improvements to rocket engine components and rocket engine operational techniques. In one example, a rocket engine propellant injection apparatus is provided that includes a manifold formed into a single body by an additive manufacturing process and comprising a fuel cavity and an oxidizer cavity. The manifold also includes one or more propellant feed stubs, the one or more propellant feed stubs protruding from the manifold and formed into the single body of the manifold by the additive manufacturing process, with at least a first stub configured to carry fuel to the fuel cavity and at least a second stub configured to carry oxidizer to the oxidizer cavity. The manifold also includes a plurality of injection features formed by apertures in a face of the manifold, ones of the plurality of injection features configured to inject the fuel and the oxidizer for combustion.

A feed system for feeding a rocket engine with a liquid propellant includes a feed circuit, and a device to vary a volume of gas in the feed circuit. The device is configured to cause a volume of gas in the feed circuit to vary while the rocket engine is in operation. The device to vary gas volume includes at least one variable-flow-rate gas injector to inject gas into the liquid propellant in the feed circuit. Methods of suppressing a POGO effect are also provided.

A system for managing propellant and pressurant for in-space propulsion of a spacecraft is provided. The system includes a conformal fuel tank having an ullage operatively connected for pressurization and a propellant management device (PMD) to wick propellant to a liquid port of the conformal fuel tank. The system further includes a pneumatic circuit including a tank pressurant vent valve for adjustment of operating pressure prior to refueling operations; a vent to release excess pressurant; a pressurant metering vent valve to provide control and safety relief for the pressurant; a check valve to prevent backflow; a pressurant cat bed for decomposing propellant into pressurant; a repressurizing valve to release pressurant once cooled; a burst disk to provide overpressure safety relief; a series of propellant extraction valves to intake a predetermined quantity of propellant for decomposition; and a pressure regulator that delivers proper pressure to a series of thrusters.

Provided is an ignition safety system arming confirmation device and an arming monitoring system including the same, and more particularly, an electro-mechanical ignition safety system arming confirmation device for ignition of a rocket motor and an arming monitoring system including the same, which provides greater accuracy in detecting an arming status and a safe status by using a permanent magnet and a Hall sensor.