Pintle injector rocket with expansion-deflection nozzle

The present invention provides a rocket engine (10) that is self-compensating on nozzle thrust coefficient for varying ambient backpressures. The rocket engine (10) includes a combustion chamber (12) having an injector end (14) and a nozzle end (16). A propellant injector (20) is in fluid communication between a propellant line and an inside periphery of the combustion chamber injector end (14). A nozzle throat (18) is formed at the nozzle end (14) of the combustion chamber (12). A nozzle exit cone (22) extends outwardly from the nozzle throat (18). A plug support (30) is coupled between a nozzle plug (28) and the propellant injector (20). The nozzle plug (28) aerodynamically self-compensates for changes in ambient backpressure at the nozzle exit cone (22) such that the nozzle thrust coefficient is maximized for any ambient backpressure.