The Aerojet M-1 was the largest and most powerful liquid-hydrogen-fueled liquid-fuel rocket engine to be designed and component-tested. It was originally developed during the 1950s by the US Air Force. The M-1 offered a baseline thrust of 6.67 MN (1.5 million lbf) and an immediate growth target of 8 MN (1.8 million lbf). If built, the M-1 would have been larger and more efficient than the famed F-1 that powered the first stage of the Saturn V rocket to the Moon.