Patent ID: 7886519

Claim:
A method of controlling solid propellant burn rate, comprising the steps of: disposing the solid propellant in a vessel; disposing a control valve between, and in fluid communication with, the vessel and a propellant gas load, the control valve movable between a closed position and a full-open position; igniting the solid propellant in the vessel to thereby generate propellant gas; moving the control valve between the closed position, in which the propellant gas load is fluidly isolated from the vessel, and the full-open position, in which the propellant gas load is fluidly coupled to the combustion chamber, at an operating frequency and with a valve duty cycle, the valve duty cycle being a ratio of time the control valve is in the full-open position to time it takes the control valve to complete one movement cycle at the operating frequency; and varying the valve duty cycle with time to attain a desired solid propellant burn rate.