Small thruster throttle valve with integrated positive isolation

An integrated throttle valve system for propellant flow modulation, comprising:

• a housing defining a centerline and an internal cavity forming a cavitating venturi, the internal cavity comprising a converging inlet, a throat, and a diverging diffuser arranged sequentially along the centerline;
• a modulating pintle translatable along the centerline within the internal cavity and comprising a bulb;
• an actuator assembly coupled to the housing and comprising a mechanical drive train configured to translate the modulating pintle to define a variable annular orifice between the modulating pintle and the throat to modulate a propellant flow;
• and
• a magnetic circuit positioned within the actuator assembly and configured to generate a passive latching force that biases the modulating pintle toward a position where the bulb contacts the converging inlet to provide positive isolation of the propellant flow in a fail-closed state.

A method for propellant flow modulation in a spacecraft propulsion system, the method comprising:

• translating a modulating pintle along a centerline of a housing to define a variable annular orifice between the modulating pintle and a throat of the housing;
• inducing cavitation at the throat to decouple a propellant flow from downstream pressure fluctuations;
• modulating the propellant flow through a linear range of at least 10:1 based on a longitudinal position of the modulating pintle;
• and
• biasing a bulb of the modulating pintle toward a converging inlet of the housing using a passive magnetic force to form a fluidic seal for positive isolation of the propellant flow during a non-operational state.