Saturn I and Saturn IB, the Saturn V's smaller siblings
The Saturn V was only the largest member of a family. Before it, the Saturn I flew 10 times from 1961 to 1965 to prove engine clustering and hydrogen propulsion; the Saturn IB, an upgraded version carrying the same S-IVB stage later used as the Saturn V's third stage, flew 9 times from 1966 to 1975. A Saturn IB launched Apollo 7, the first crewed Apollo flight, and the last Saturn rocket of all lifted off for the Apollo-Soyuz mission in July 1975.
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Why "Saturn"?
In 1958, Wernher von Braun's team at Redstone Arsenal in Huntsville was studying a heavy booster provisionally called Juno V. Early in 1959 it was renamed Saturn, because it followed the Jupiter missile, just as the planet Saturn comes after Jupiter in distance from the Sun. A series of configurations, C-1 through C-5, followed; the C-1 became the Saturn I and the C-5, selected in 1962 for the lunar missions, became the Saturn V.
Saturn I: a flying test bed
Without time to develop a giant engine, the Saturn I used an ingenious shortcut. Its S-I first stage clustered eight Rocketdyne H-1 engines beneath a bundle of tanks derived from existing missiles: eight Redstone-diameter tanks arranged around a central Jupiter-diameter tank. Many engineers doubted such a cluster could work without destructive vibration or interference; the first flight, on 27 October 1961, proved them wrong. Early first stages were built by Marshall Space Flight Center, later ones by Chrysler.
The first four flights ("Block I") carried a dummy upper stage; two even released their water ballast in the upper atmosphere as a scientific experiment. From January 1964, "Block II" flights carried a real second stage, Douglas's S-IV, powered by six small RL10 hydrogen engines, the first operational use of that technology on a large launcher. The final flights orbited boilerplate Apollo spacecraft and three Pegasus satellites, huge panels that measured how often micrometeoroids struck. Ten flights, no failures.
Saturn IB: Apollo's Earth-orbit rocket
The Saturn IB kept a lighter, more powerful S-IB first stage, built by Chrysler with eight uprated H-1s, but replaced the S-IV with Douglas's S-IVB, powered by a single J-2 engine. That was essentially the stage that would become the Saturn V's third stage, so the Saturn IB flight-qualified a third of the Moon rocket before the big vehicle ever flew. It could put about 20 t (44,000 lb) into low Earth orbit, enough for a full Apollo spacecraft or a lunar module.
Three uncrewed flights in 1966 tested the Apollo spacecraft and the behavior of liquid hydrogen in orbit. On 27 January 1967, during a ground test atop vehicle AS-204, a fire in the command module killed astronauts Gus Grissom, Ed White and Roger Chaffee: the Apollo 1 tragedy. A year later the same rocket launched the first lunar module, uncrewed, on Apollo 5.
On 11 October 1968, Apollo 7 (Walter Schirra, Donn Eisele, Walter Cunningham) lifted off on a Saturn IB for eleven days in Earth orbit. The Apollo spacecraft, redesigned after the fire, proved sound, clearing the way for Apollo 8, the first crewed Saturn V, two months later.
After the Moon: Skylab and Apollo-Soyuz
The Saturn IB returned to service in 1973 to carry all three crews to the Skylab station. These flights left from Pad 39B, built for the Saturn V; the shorter rocket stood on a pedestal nicknamed the "milkstool" so that its spacecraft lined up with the tower's access arms.
The family's final flight, on 15 July 1975, carried Thomas Stafford, Vance Brand and Deke Slayton on the Apollo-Soyuz Test Project. On 17 July their spacecraft docked with Soyuz 19, crewed by Alexei Leonov and Valeri Kubasov: the first joint US-Soviet space mission and a symbolic handshake at the height of détente. Americans would not fly in orbit again until the Space Shuttle in 1981.
The Saturn family at a glance
| Rocket | Flights | Years | Stages | Liftoff thrust | Payload to low Earth orbit |
|---|---|---|---|---|---|
| Saturn I | 10 | 1961–1965 | S-I (8 H-1), S-IV (6 RL10) | about 6.7 MN (1.5 million lbf) | about 9 t |
| Saturn IB | 9 | 1966–1975 | S-IB (8 H-1), S-IVB (1 J-2) | about 7.1 MN (1.6 million lbf) | about 20 t |
| Saturn V | 13 | 1967–1973 | S-IC (5 F-1), S-II (5 J-2), S-IVB (1 J-2) | about 34.5 MN (7.5 million lbf) | about 140 t |
An unused Saturn IB, SA-209, kept in reserve for a possible Skylab rescue, lies on its side in the Rocket Garden at Kennedy Space Center. Other examples and mock-ups can be seen in Huntsville, as described on where to see a Saturn V. The full flight list of the big sister is in Saturn V launches.
FAQ
What is the difference between the Saturn I and Saturn IB?
Both used a first stage with eight H-1 engines, more powerful on the IB. The main difference was the second stage: the S-IV with six RL10 engines on the Saturn I, the S-IVB with one J-2 on the Saturn IB, which roughly doubled payload.
What rocket launched Apollo 7?
A Saturn IB, on 11 October 1968, from Launch Complex 34 at Cape Canaveral. It was the first crewed flight of the Apollo program.
Was there a Saturn II, III or IV?
No. Intermediate configurations were studied on paper, but only the Saturn I, IB and V were built and flown.
When was the last Saturn rocket launched?
On 15 July 1975, when a Saturn IB launched the Apollo crew of Apollo-Soyuz. The last Saturn V had flown two years earlier, for Skylab.
Sources
- Roger E. Bilstein, Stages to Saturn, NASA SP-4206, 1980.
- Edward Clinton Ezell and Linda Neuman Ezell, The Partnership: A History of the Apollo-Soyuz Test Project, NASA SP-4209, 1978.
- NASA History Office