The S-III (pronounced "S 3") was a proposed third stage of the early Saturn C designs for a five-stage
Saturn launch vehicle. The Saturn C configurations were based on a "building block" approach, in which the upper stages would be test-flown before the intermediate stages. The S-III was to have been fueled with
liquid oxygen
Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an a ...
and
liquid hydrogen
Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...
and powered by two
J-2 engines. The original
Saturn C-2
The Saturn C-2 was the second rocket in the Saturn (rocket family), Saturn C series studied from 1959 to 1962. The design was for a four-stage launch vehicle that could launch 21,500 kg (47,300 lb) to low Earth orbit and send 6,800 ...
design would have been a three- or four-stage launch vehicle using the
S-I plus S-III plus
S-IV
The S-IV was the second stage of the Saturn I rocket used by NASA for early flights in the Apollo program.
The S-IV was manufactured by the Douglas Aircraft Company and later modified by them to the S-IVB, a similar but distinct stage used on th ...
stages plus, for some missions,
S-V
The S-V (pronounced "S-five") was the third stage of the Saturn I rocket. It was built by Convair. It was designed to use two RL-10A-1 engines fueled by liquid hydrogen (LH2) and liquid oxygen (LOX) in tanks utilizing a common bulkhead to separat ...
.
References
Free return trajectory simulation, Robert A. Braeunig, August 2008*
*Stuhlinger, Ernst, et al., Astronautical Engineering and Science: From Peenemuende to Planetary Space, McGraw-Hill, New York, 1964.
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Rocket stages