 The Space Shuttle Main Engine's turbopumps spun at over 30,000 rpm, delivering 150 lb (68 kg) of liquid hydrogen and 896 lb (406 kg) of liquid oxygen to the engine per second.Most turbopumps are centrifugal - the fluid enters the pump near the axis and the rotor accelerates the fluid to high speed.The fluid then passes through a diffuser which is a progressively enlarging pipe, which permits recovery of the dynamic pressure.