The Saturn 1B was a rocket used to test various spacecraft
and other systems for the Apollo project
in advance of the Saturn V
A modified version of its predeccesor, the Block II Saturn I, the first stage was a cluster of eight lengthened Redstone missile tanks surrounding a lengthended Jupiter rocket tank. Eight H-1 engines provided thrust by burning a kerosene and liquid oxygen mix. This stage was lighter than the corresponding Block II Saturn I first stage and also had modified stabilizer fins, along with other minor improvements.
The second stage used an uprated version of the Block II Saturn I's S-IV stage, the S-IVB. The S-IVB had a larger diameter and used one J-2 engine instead of six RL-10 engines. Like the S-IV, it burnt liquid hydrogen and oxygen.
The third stage was either an Apollo spacecraft or a test/dummy payload.
The first Saturn IB flew on February 26, 1966. Test flights continued until the first manned Apollo mission, Apollo 7 that tested the Command and Service modules in Earth orbit. This was launched on October 11, 1968.
Although the Saturn I's role in the race the moon was over, it was used three times after the lunar landings to send crews to Skylab. A final fourth launch on July 15, 1975 launched the U.S.'s half of the Apollo-Soyuz mission.
The Saturn IB was 223.4 feet tall and 22.5 feet in diameter.