S-IV
Template:Short description Template:Infobox rocket stage 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 the Saturn IB and Saturn V rockets.<ref name="stages1">Template:Harvnb</ref>
The S-IV stage was a large LOX/LH2-fueled rocket stage used for the early test flights of the Saturn I rocket. It formed the second stage of the Saturn I and was powered by a cluster of six RL-10A-3 engines. Each one of the engines supplied Template:Convert of thrust for a total of about Template:Convert. The cryogenic LH2 (liquid hydrogen) and LOX (liquid oxygen) tanks were separated by a common bulkhead. The forward bulkhead of the LOX tank formed the aft bulkhead of the LH2 tank. This saved up to 20% of structural weight.<ref name="stages2">Template:Harvnb</ref><ref>Template:Harvnb</ref>
Flight history
| Mission serial number | Launch date (UTC) | Image | Launch notes |
|---|---|---|---|
| SA-1 | October 27, 1961 15:06:04 |
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| SA-2 | April 25, 1962 14:00:34 |
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| SA-3 | November 16, 1962 17:45:02 |
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| SA-4 | March 28, 1963 20:11:55 |
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| SA-5 | January 29, 1964 16:25:01 |
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| SA-6 | May 28, 1964 17:07:00 |
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| SA-7 | September 18, 1964 16:22:43 |
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| SA-9 | February 16, 1965 14:37:03 |
File:Second Stage for SA-9.jpg | Template:Bulleted list |
| SA-8 | May 25, 1965 07:35:01 |
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| SA-10 | July 30, 1965 13:00:00 |
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