The S-IC stage

The S-IC in the transfer aisle of the Vertical Assembly Building (VAB). This particular stage is waiting to be installed as the first stage of the SA-507. SA-507 is the serial number of the Saturn V launch vehicle which was used for the Apollo 12 mission. May 7, 1969
credit to NASA
Scanning credit to Kipp Teague

General information

The S-IC stage had a relatively conservative design: separate LOx and fuel tanks connected with an intertank and a solid crossbeamlike thrust structure at the base. The concept of clustering engines to obtain higher thrust had been proven by the Saturn IB with its 8 thrust engines in the first stage. The development of the Saturn V could be built on that experience. The construction of the S-IC stage however was a real challenge because of its sheer size. Welding of large tank structures with very tight tolerances was one of the many challenges.

The F-1 engine
The gigantic F-1 engine used a conventional mixture of RP-1 (kerosene) and liquid oxygen. During the development of this engine, designers initially assumed that they basically had to scale up already proven designs of much smaller thrust engines. But the development appeared to be not that straightforward. Early firing tests on the F-1 engine revealed harmful combustion instabilities inside the combustion chamber, which turned out to be a major problem, difficult to tackle and threatened to jeopardize the Apollo Program. Lot of research went into the redesign of the F-1 engine propellant injector. The new designed injector plate with its around 5000 orifices, through which the RP-1 and the liquid oxygen was pumped into the combustion chamber with a high pressure turbo pump, resulted in an improved spray pattern of the propellants and gave the F-1 engine excellent damping qualities with respect to combustion instabilities.

S-IC stage main parts

From bottom up:
  1. The five F-1 engines
  2. The thrust structure
  3. The fuel tank
  4. The intertank
  5. The liquid oxygen tank
  6. The forward skirt


  1. Height      : 41.40 meter
    Diameter  : 9.90 meter (excluding fins)
    Mass empty stage           : 130.64 Ton
    Mass of propellants        : 2151.03 Ton
    Mass of loaded stage      : 2281.67 Ton
    Amount of fuel:
    Liquid Oxygen : 1499.82 Ton, 1 318 583 liter (Mass dens. LOx: 1.137 kg/ltr)
    Kerosene RP1 : 651.21 Ton, 815 089 liter (Mass dens. RP1: 0.799 kg/ltr).
  2. Typical flight profile
    Typical flight parameters at the moment of S-IC stage burn-out:
    • Altitude : 67 km
    • Downrange distance : 90 km
    • Velocity : 2 355 m/sec (8 479 km/hr; 7.2 Mach)
    • Time of operation : 160 sec.
  3. F-1 engines:
    F-1 engine thrust : 690 Tons (metric)
    It took the five F-1 engines 8 seconds to build up 3450 Tons (metric) of thrust from the moment of ignition.
    Height of F-1 engine      : 5.64 meter
    Diameter of F-1 engine  : 3.72 meter
    Mass of F-1 engine       : 8.4 Ton
    Combustion pressure inside an F-1 chamber : 77 bar
    Combustion chamber diameter probably around 1 meter.
    Fuel consumption rate per F-1 engine : 2.671 Ton/sec.
    Specific Impulse at ground level : 280 sec.
  4. Manufacturer of the F-1 engines: North American Aviation, Rocketdyne division
    Manufacturer of the S-IC stage: Boeing Aircraft Company

This picture shows the flight path of the SA-503 (Apollo 8) during ascent. The S-IC performed its task in only the first 2½ minutes of the flight and was then disposed of. After a nearly 7 minutes ballistic flight, the S-IC stage plunged into the Atlantic Ocean about 635 km off the east coast of Florida.

Apollo 8 ground track during ascent

This picture shows the ground track of the SA-503 (Apollo 8) during ascent. The S-IC performed its task in only the first 2½ minutes of the flight and was then disposed of. The S-IC stage plunged into the Atlantic Ocean about 655 km off the east coast of Florida.

Plan View S-IC stage Forward section, Looking down

The S-IC stage

From top to bottom: the forward skirt, the oxygen tank, the intertank, the fuel tank and the thrust structure

Plan View S-IC stage Aft section, Looking up

Five F-1 eingines

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Copyright 2006 by   Sander Panhuyzen
All pictures and drawings contained on and through these pages are the author's, unless otherwise noted. No unauthorized reproduction without permission.