page_title: Saturn IB
section_title: S-IVB-200 stage
hierarchical_section_title: Saturn IB / Specifications / S-IVB-200 stage
caption_attribution_description: English: Saturn IB second stage the S-IVB 日本語: サターンIB 型ロケット第二段S-IVB
context_page_description: The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration for the Apollo program. It replaced the S-IV second stage of the Saturn I with the much more powerful S-IVB, able to launch a partially fueled Apollo command and service module or a fully fueled Apollo Lunar Module into low Earth orbit for early flight tests before the larger Saturn V needed for lunar flight was ready.
  By sharing the S-IVB upper stage, the Saturn IB and Saturn V provided a common interface to the Apollo spacecraft. The only major difference was that the S-IVB on the Saturn V burned only part of its propellant to achieve Earth orbit, so it could be restarted for trans-lunar injection. The S-IVB on the Saturn IB needed all of its propellant to achieve Earth orbit.
  The Saturn IB launched two uncrewed CSM suborbital flights to a height of 162km, one uncrewed LM orbital flight, and the first crewed CSM orbital mission. It also launched one orbital mission, AS-203, without a payload so the S-IVB would have residual liquid hydrogen fuel.
context_section_description: The S-IVB was built by the Douglas Aircraft Company at Huntington Beach, California. The S-IVB-200 model was similar to the S-IVB-500 third stage used on the Saturn V, with the exception of the interstage adapter, smaller auxiliary propulsion control modules, and lack of on-orbit engine restart capability. It was powered by a single Rocketdyne J-2 engine. The fuel and oxidizer tanks shared a common bulkhead, which saved about ten tons of weight and reduced vehicle length over ten feet.
  General characteristics
  Length: 58.42 ft (17.81 m)
  Diameter: 21.67 ft (6.61 m)
  Engine
  1 J-2
  Thrust: 200,000 lbf (890 kN)
  Burn time: ~ 420 s
  Fuel: LH₂/LOX
caption: Diagram of the S-IVB second stage of the Saturn IB
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