Saturn is a family of large rockets developed for the U.S. Apollo program. The Saturn rocket was the outcome of studies begun
in the late 1950s by Wernher von Braun and his research group at the Army Ballistic Missile Agency (later named the George C. Marshall Space Flight Center) in Huntsville, Ala. (See rockets, missiles, and space launch vehicles.) Saturn I The two-stage Saturn I had a cluster of eight Rocketdyne H-1
engines in the first stage, each of which delivered a thrust of 836,000 newtons, or 85,277 kg (188,000 lb). A central
liquid-oxygen tank 255 cm (105 in) in diameter was surrounded by a cluster of eight tanks 178 cm (70 in) in diameter, four of which contained kerosene and four liquid oxygen. The second stage of the Saturn had six liquid oxygen-liquid hydrogen Pratt & Whitney RL-10 engines, each of which gave 66,700 newtons, or 6,804 kg (15,000 lb) of thrust. The first test launch of the Saturn I rocket was made at Cape Canaveral, Fla., in October 1961 with only the first stage "live." A live upper stage was flown for the first time in January 1964, placing a payload of 17,191 kg (37,900 lb) into Earth orbit. After two test flights of engineering models of the Apollo spacecraft, Saturn I rockets orbited three huge Pegasus meteoroid-detection satellites in 1965. Saturn IB The need to fly still heavier payloads in the Apollo program led to the development of the Saturn IB. The first stage of the Saturn IB, built by the Chrysler Corporation, was a slightly upgraded first stage of Saturn I, in which the eight H-1 engines developed a total thrust of about 7,117,000 newtons, or 725,700 kg (1,600,000 lb). The second stage (S-IVB), built by Douglas Aircraft Company, had a single J-2 engine developing 900,000 newtons, or 90,720 kg (200,000 lb) of thrust from liquid oxygen and liquid hydrogen. On Oct. 11, 1968, after only four test flights, the improved Saturn launched Walter Schirra, Donn Eisele, and Walter Cunningham on the Apollo 7 flight, which completed 163 Earth orbits. Saturn IBs were also used to fly three astronaut crews to the Skylab space station in 1973-74. A final mission in July 1975 involved the launch of a manned Apollo spacecraft in the Apollo-Soyuz Test Project. Altogether a total of 19 Saturn I and IB rockets were launched between October 1961 and July 1975, without any failures. Saturn V The Saturn V rocket stood 110.6 m (363 ft) tall with the Apollo spacecraft installed. Fully loaded it weighed 2.9 million kg (6.4 million lb). Its S-IC first stage, built by the Boeing Company, had a diameter of 10.1 m (33 ft) and was powered by five Rocketdyne F-1 engines that burned liquid oxygen and kerosene to produce more than 33.8 million newtons, or 3.45 million kg (7.6 million lb) of thrust. The four outer engines could swivel to steer the rocket. The S-II second stage, built by Rockwell International, had a similar arrangement of five Rocketdyne J-2 engines burning liquid oxygen and liquid hydrogen. Total thrust of this stage was about 5,132,000 newtons, or 523,328 kg (1,153,712 lb). The S-IVB third stage, built by McDonnell Douglas Astronautics, had a diameter of 6.6 m (21.7 ft). A single gimbal-mounted Rocketdyne J-2 engine burning liquid oxygen and liquid hydrogen delivered a thrust of 926,300 newtons, or 94,458 kg (208,242 lb). Atop the third stage was the IBM-built Instrument Unit (IU), which contained the guidance equipment for all three stages. Above the IU were the Apollo modules. Altogether, 13 Saturn V rockets were launched without a single loss. The first was launched unmanned on Nov. 9, 1967. It placed the Apollo 4 spacecraft into orbit for a reentry test of the command module. After one more unmanned test flight, the third rocket, launched Dec. 21, 1968, allowed the Apollo 8 astronauts to reach the vicinity of and complete ten orbits around the MoonÑthe first manned spaceflight to another celestial body. After two additional manned Apollo spacecraft were launched, the sixth Saturn V, launchedon July 16, 1969, resulted in the first manned lunar landing during the Apollo 11 mission. Six more Saturn V rockets were used for the remaining Apollo missions. After the Apollo program ended, a two-stage Saturn V placed the Skylab space station into Earth orbit on May 14, 1973. This two-stage Saturn V exchanged the "live" third stage for the Skylab, which itself was made from an S-IVB stage without the propulsion system. Overall height of the Saturn V/Skylab combination was 101.8 m (334 ft).