Stage 1 (S-IC)

The Apollo 10 S-IC stage is hoisted in the VAB for stacking

The S-IC (pronounced "ess one see") was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer. It was 42 meters tall and 10 meters in diameter, and provided 33,000 kN of thrust to get the rocket through the first 61 kilometers of ascent. Of the five F-1 engines, one was fixed in the center, while the four on the outer ring could be hydraulically turned to control the rocket.


The Boeing Company was awarded the contract to manufacture the S-IC on December 15, 1961. By this time the general design of the stage had been decided on by the engineers at the Marshall Space Flight Center (MSFC). The main place of manufacture was the Michoud Assembly Facility, New Orleans. Wind tunnel testing took place in Seattle and the machining of the tools needed to build the stages at Wichita, Kansas.

MSFC built the first three test stages (S-IC-T, the S-IC-S, and the S-IC-F) and the first two flight models (S-IC-1 and -2). They were built using tools produced in Wichita.

It took roughly 7 to 9 months to build the tanks and 14 months to complete a stage. The first stage built by Boeing was S-IC-D, a test model.


Cutaway diagram of the S-IC

The largest and heaviest portion of the S-IC was the thrust structure, weighing 21 metric tons. It was designed to support the thrust of the five engines and redistribute it evenly across the base of the rocket. There were four anchors which held down the rocket as it built thrust. These were among the largest aluminum forgings produced in the U.S. at the time, 4.3 meters long and 816 kilograms in weight. The four stabilising fins withstood a temperature of 1100 °C.

Above the thrust structure was the fuel tank, containing 770,000 liters of RP-1 fuel. The tank itself had a mass of 11 metric tons dry and could release 7300 liters per second. Nitrogen was bubbled through the tank before launch to keep the fuel mixed. During flight the fuel was pressurized using helium, that was stored in tanks in the liquid oxygen tank above.

Saturn V first stages S-1C-10, S-1C-11, and S-1C-9 at Michoud Assembly Facility

Between the fuel and liquid oxygen tanks was the intertank.

The liquid oxygen tank held 1,204,000 liters of LOX. It raised special issues for the designer. The lines through which the LOX ran to the engine had to be straight and therefore had to pass through the fuel tank. This meant insulating these lines inside a tunnel to stop fuel freezing to the outside and also meant five extra holes in the top of the fuel tank.

Two solid motor retrorockets were located inside each of the four conical engine fairings. At separation of the S-IC from the flight vehicle, the eight retrorockets fired, blowing off removable sections of the fairings forward of the fins, and backing the S-IC away from the flight vehicle as the engines on the S-II stage were ignited.

Stages built
Serial number Use Launch date Current location Notes
S-IC-Tstatic test firingpart of Saturn V display at Kennedy Space Center
S-IC-Sstructural load testing (had no engines)location unknown (last seen at MSFC)
S-IC-Ffacilities testing for checking out launch complex assembly buildings and launch equipmentlocation unknown
S-IC-Dground test dynamics modelU.S. Space & Rocket Center, Huntsville, Alabama
S-IC-1Apollo 4November 9, 1967Manufactured by MSFC
S-IC-2Apollo 6April 4, 1968Manufactured by MSFC; carried TV and cameras on Boattail and Forward skirt
S-IC-3Apollo 8December 21, 196830.2N 74.117WManufactured by Boeing (as with all subsequent stages); weighed 560 kg less than previous allowing 36 kg more payload
S-IC-4Apollo 9March 3, 196930.183N 74.233W
S-IC-5Apollo 10May 18, 196930.183N 74.2WLast flight for S-IC R&D Instrumentation
S-IC-6Apollo 11July 16, 196930.217N 74.033W
S-IC-7Apollo 12November 14, 196930.267N 74.9W
S-IC-8Apollo 13April 11, 197030.183N 74.067W
S-IC-9Apollo 14January 31, 197129.833N 74.05W
S-IC-10Apollo 15July 26, 197129.7N 73.65W
S-IC-11Apollo 16April 16, 197230.2N 74.15W
S-IC-12Apollo 17December 7, 1972
S-IC-13Skylab 1May 14, 1973engine shutoff changed to 1-2-2 from 1-4 to lessen loads on Apollo Telescope Mount
S-IC-14UnusedSaturn V display at Johnson Space CenterScheduled for Apollo 18/19
S-IC-15UnusedMichoud Assembly FacilityDesignated but never used as a backup Skylab launch vehicle