Rocket engine burner with porous metal injector for throttling over a large thrust range

A rocket engine with stable combustion over a thrust range of full thrust to very low thrust, the rocket engine comprising:

• a secondary propellant source that provides a gaseous fuel at a flow rate that varies over the thrust range;
• a primary propellant source that provides a liquid oxidizer at a flow rate that varies over the thrust range;
• a rocket engine burner comprising:
• a combustion chamber having an inlet and an outlet;
• a propellant injector assembly comprising:
• one or more hollow injectors;
• a porous injector that extends across the inlet of the combustion chamber and has one or more openings therethrough to receive the hollow injectors;
• a secondary propellant manifold in communication with the secondary propellant source and the hollow injectors to provide the hollow injectors with the gaseous fuel, the provided gaseous fuel flowing through the hollow injectors and being injected into the combustion chamber with an injection velocity that is approximately constant despite changes in the flow rate of the gaseous fuel;
• and
• a primary propellant manifold in communication with the primary propellant source and the porous injector to provide the porous injector with the liquid oxidizer, the provided liquid oxidizer flowing through the porous injector and being injected into the combustion chamber with a pressure drop across the porous injector that is approximately linear with changes in the flow rate of the liquid oxidizer;
• and
• an ignitor in communication with the combustion chamber to ignite the injected gaseous fuel and liquid oxidizer to produce the stable combustion over the thrust range as the flow rates of the gaseous fuel and the liquid oxidizer are varied, the stable combustion having combustion products that exit the outlet of the combustion chamber.