A descendant of the early V-2 engines, the H-1 was a liquid-propellant rocket engine developed for use in the Saturn 1 and Saturn 1B rockets of the Apollo program. Launched with a cluster of eight H-1 engines, the Saturn 1 was used for testing and the Saturn 1B was used for testing and manned launches including Apollo 7, the three Skylab missions, and the Apollo-Soyuz mission. On these missions, eight H-1 engines provided over 1.6 million lbf of thrust to place payloads in Low Earth Orbit. The engine used RP-1 kerosene and liquid oxygen as fuel and oxidizer, produced 205,000 lbf of thrust, and was manufactured by the Rocketdyne Division of North American Aviation. On November 21, 1963, the day before he was assassinated, President John F. Kennedy cited the Saturn 1 SA-5 launch with its eight H-1 engines as the event that would finally place the U.S. heavy lift capability ahead of the Soviet Union after six years of Soviet advantage since the launch of Sputnik.