Saturn 1B

The Saturn IB rocket for the AS-202 mission.

The Saturn IB was an uprated version of the Saturn I, which featured a much more powerful second stage, the S-IVB. Unlike the earlier Saturn I, the IB had enough throw weight to launch the Apollo Command/Service Module or Lunar Module into Earth orbit, which made it invaluable for testing the Apollo spacecraft while the larger Saturn V needed to send them to the moon was still being developed. The Saturn IB was later used for manned Skylab flights, and the Apollo-Soyuz Test Project. The final production run (such as Skylab launch vehicles) did not have the alternating black and white tanks on the first stage that were hallmarks of the earlier runs.

S-IB stage

The S-IB stage is an eight engine booster for Earth orbital missions. It is composed of nine propellant containers, eight fins, a thrust structure assembly, eight H-1 rocket engines, and many other components. The propellant containers consist of eight Redstone tanks (Four holding LOX and four holding RP-1.) clustered around a Jupiter rocket tank, which contains LOX. The four outboard engines can gimbal, meaning they can be steered to properly guide the rocket. This requires a few more engine components.

Technical Data
Parameter S-IB - 1st Stage S-IVB - 2nd Stage Instrument Unit Apollo Spacecraft
Height (m)25.517.81.0024
Diameter (m)
Gross mass (kg)458,107119,9201,98020,788
Empty mass (kg)45,26713,31122514,098
EnginesEight - H-1One - J-2-One SPS
Thrust (kN)7,5821,020-97.86
Isp (s)288421-314
Isp (kNĚs/kg)2.824.13-3.08
Burn duration (s)150470-635
Saturn IB Launches
Launch Event Time (s) Altitude (km) Range (km)
Ignition Command-3.02..
First Motion-0.19..
Initiate Pitch Maneuver10.0..
Initiate Roll Maneuver10.0..
End Roll Maneuver38.0..
Mach One62.187.63.
Max Q75.512.16.
Freeze Tilt134.40..
Inboard Engine Cutoff140.65..
Outboard Engine Cutoff144.32..
Ullage Rockets Ignition145.37..
S-IB / S-IVB Separation145.59..
S-IVB Ignition146.97..
Ullage Rocket Burnout148.33..
Ullage Rocket Jettison156.58..
Jettison LES163.28..
Start Pitch Over613.95..
S-IVB Cutoff616.76..
Orbit Insertion626.76..
Start S/C Sep Sequence663.11..
Spacecraft Separation728.31..


  • Height: 83.6 ft (25.5 m)
  • Diameter: 21.7 ft (6.6 m)
  • Number of fins: 8
  • Finspan: 18 ft (5.5 m)
  • Engines: 8 H-1
  • Thrust: 1,600,000 lbf (7.1 MN)
  • Fuel: RP-1 (Refined kerosene) 41,000 US gal (155 m³)
  • Oxidizer: Liquid oxygen (LOX) 66,000 US gal (250 m³)
  • Burn time: 2.5 min
  • Burnout altitude: 42 miles (68 km)

S-IVB stage

The S-IVB stage is generally identical to the third stage of the Saturn V, with the notable exceptions of its interstage adapter, smaller auxiluary propulsion control modules, and its lack of an on-orbit engine restart capability. It is powered by a single J-2 engine, which is gimballed for flight control. This stage has a "common bulkhead," meaning that the propellant and oxidizer tanks share a bulkhead. This saved about ten tons of weight and reduced vehicle length over ten feet.

  • Height: 58.4 ft (17.8 m)
  • Diameter: 21.7 ft (6.6 m)
  • Number of fins: 0
  • Engines: 1 J-2
  • Thrust: 200,000 lbf (890 kN)
  • Fuel: Liquid hydrogen (LH2) 64,000 US gal (242 m³)
  • Oxidizer: Liquid oxygen (LOX) 20,000 US gal (76 m³)
  • Burn time: approx. 7 min
  • Burnout altitude (for Saturn IB): orbit