Abstract: A simplified rocket engine a rocket engine has a rotor assembly with an ultracentrifugal (over 200 meters/second tangential velocity) liquid pump arranged around a combustion chamber so as to provide both forced convective and Coriolis-effect and centripetal-acceleration enhanced free convective regenerative cooling to the combustion chamber while pressurizing the liquid propellant. Both fuel and oxidizer may be stored a cryogenic temperatures and pumped around the combustion chamber for regenerative cooling. The combustion chamber may be structured to rotate together with the pump to provide Coriolis-effect and centripetal-acceleration enhanced combustion. The rotor assembly is driven directly by a tangential component of the primary thrust vector by means of tilted nozzles or by vanes, flutes, or other reaction surfaces.