S-IB

The S-IB stage was the first stage of the Saturn IB launch vehicle, which was used for Earth orbital missions.^[2] It was an upgraded version of the S-I stage used on the earlier Saturn I rocket and was composed of nine propellant containers, eight fins, a thrust structure assembly, eight H-1 rocket engines, and many other components. It also contained the ODOP transponder. The propellant containers consisted of eight Redstone-derived tanks (four holding liquid oxygen (LOX) and four holding RP-1) clustered around a Jupiter rocket-derived tank containing LOX. The four outboard engines gimballed to steer the rocket in flight, which required a few more engine components. The S-IB burned for nearly 2.5 minutes before separating at an altitude of 42 miles (68 km).

S-IB

Diagram of the S-IB first stage of the Saturn IB rocket
Manufacturer	Chrysler[1]
Country of origin	United States
Used on	Saturn IB (stage 1)
General characteristics
Height	25.5 m (84 ft)
Diameter	6.6 m (22 ft)
Gross mass	448,648 kg (989,100 lb)
Derived from	S-I
Launch history
Status	Retired
Total launches	9
Successes (stage only)	9
First flight	February 26, 1966
Last flight	July 15, 1975
Powered by	8 H-1 engines
Maximum thrust	7.1 MN (1,600,000 lbf)
Specific impulse	296 s (2.90 km/s)
Burn time	155 seconds
Propellant	RP-1/LOX

Specifications

• Height: 80.17 ft (24.44 m)
• Diameter: 21.42 ft (6.53 m)
• Number of fins: 8
• Finspan: 39.42 ft (12.02 m)
• Engines: 8 Rocketdyne H-1
• Thrust: 1,600,000 lbf (7,100 kN)
• Fuel: RP-1 (Refined kerosene) 41,000 US gal (155 m³)
• Oxidizer: Liquid oxygen (LOX) 66,277 US gal (251 m³) nominal capacity including 1.5% ullage volume (43,284 US gal / 163 m³ in four outer tanks plus 22,993 US gal / 87 m³ in center tank^[3])
• Burn time: 2.5 min
• Burnout altitude: 37 nmi (69 km)

Stages built

Apollo flights:^[1]

• S-IB-1: Launched 2/26/1966 on suborbital AS-201 mission.
• S-IB-3: Launched 7/5/1966 as AS-203 orbital test mission.
• S-IB-2: Launched 8/25/1966 on suborbital AS-202 test mission.
• S-IB-4: Launched 1/22/1968 on Apollo 5 orbital mission.  
• S-IB-5: Launched 10/11/1968 on crewed Apollo 7 orbital mission.

Post-Apollo Flights:^[1] 

• S-IB-6: Launched 5/25/1973 on Skylab-2 orbital mission.
• S-IB-7: Launched 7/23/1973 on Skylab-3 orbital mission.
• S-IB-8: Launched 11/16/1973 on Skylab-4 orbital mission.
• S-IB-10: Launched 7/15/1975 on ASTP orbital mission.

Hardware Not Flown:^[1]

• S-IB-9: Stacked on MLP ready to fly as Skylab backup. Now on display at Kennedy Space Center Visitor Complex.
• S-IB-11: Flight not assigned. Displayed vertically at Alabama Welcome Center until late 2023, when it was dismantled due to weathering.^[4]
• S-IB-12: Flight not assigned. Presumed scrapped at Marshall Space Flight Center in late 1970s.
• S-IB-13: Hardware scrapped.  
• S-IB-14: Hardware scrapped.  
• S-IB-15: Not built, cancelled by NASA in 1968.
• S-IB-16: Not built, cancelled by NASA in 1968.

Proposed variants

Besides the version flown as the Saturn IB stage, other versions were proposed for several vehicle concepts:^[5]

Saturn S-IB-2

The S-IB-2 stage was studied in 1960 to power the Saturn C-3.^[6] It was planned to be larger (with a height of 34.50 m and a diameter of 8.25 m), powered by two F-1 engines developing 3 million pounds-force (13 MN) of thrust, with a fueled mass of 1.6 million pounds (730 t).^[7]

Saturn S-IB-4

The S-IB-4 stage was studied in 1960 to power the Saturn C-4, using four F-1 engines.^[8]

Saturn S-IB-A

The S-IB-A stage was studied in 1965 to power the Saturn IB-A and Saturn IB-B, using eight H-1c engines.^[9]

Saturn IB-11

The IB-11 stage was studied in 1966 to power the Saturn INT-11, Saturn INT-13 and Saturn INT-14, using eight H-1b engines and UA1207 solid boosters.^[10]

Saturn IB-15

The IB-15 stage was studied in 1966 to power the Saturn INT-15, using eight H-1b engines and Minuteman first-stage strap-ons.^[11]

Saturn S-1B-4

The S-1B-4 stage was studied in 1966 to power the Saturn INT-12, using four H-1b engines and UA1205 solid boosters.^[12]