Patent ID: 7849695

Claim:
A rocket thruster assembly comprising: a nozzle providing an internal passageway-defining surface structure for receiving and expelling combustion products, the internal passageway-defining structure comprising a converging region that converges in cross section into a throat region, and a diverging region located aft of the throat region and extending radially outwardly; a valve subassembly comprising a pintle with a head portion, the head portion having a truncated substantially conical surface region terminating at an aft truncated portion coaxial with the throat region, the truncated substantially conical surface region facing the converging region and the throat region to provide a variable effective throat area therebetween, the truncated portion having a bleed passageway opening in communication with a passage leading through the head portion to a bleed cavity located on an opposite side of the head portion relative to the throat region for receiving and expelling the combustion products to counterbalance the pintle; and a thrust control subassembly operatively coupled to the pintle for moving the pintle axially back and forth relative to the throat region to a plurality of axial positions and for selectively retaining the pintle at the plurality of axial positions for changing the effective throat area; wherein the thrust control subassembly further comprises an actuator operatively coupled to the pintle for moving the pintle axially back and forth relative to the throat region and retaining the pintle at a plurality of open positions in which the pintle is spaced from the converging region and the throat region, and at a closed position in which the pintle contacts the internal passageway-defining surface structure to close at least one of the throat region and the converging region.