A turbopump is an assembly consisting of a liquid pump driven by a gas turbine, connected via a shaft. They were initially developed in the US and Germany in the 1930s and 1940s. While other use cases can exist, the primary purpose of turbopumps is to dramatically raise the pressure of liquid propellants and feed them to the combustion chamber of a rocket engine. While they have considerably higher design complexity, turbopump fed systems scale much more favorably in large rockets than pressure-fed systems, which require increasingly thick and heavy tanks to supply high chamber pressures in the engines.