PIEZOELECTRIC INJECTION SYSTEM FOR VERNIER IMPULSE THRUSTERS.

Pulsed vernier rocket engines have shown distinct control advantages in many limit-cycle operations of space and re-entry vehicles. Weight reduction requirements preclude the optimal economy of propellant utilization that can be realized by delivery of small but accurate impulse bits of thrust. The propellant flow control for production of small impulse bits by vernier rocket engines is accomplished in developed systems by pressure-fed systems employing fast-acting pneumatic or solenoid valves. Control of impulse bit repeatability and response time for bi-propellant systems is, however, limited by the opening and closing characteristics of the valves. The pulse-pumped vernier engine concept provides accurate metering of the propellants through a rapid and controllable movement of a pump plunger. The total impulse required for a programmed space maneuver is delivered in a number of discrete but accurate impulses.