S-IV

Template:Short description Template:Template other 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.

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 of thrust for a total of about . 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.

Flight history

Mission serial number	Launch date (UTC)	Image	Launch notes
SA-1	October 27, 1961 15:06:04	File:S-IV-1.jpg	Template:Bulleted list
SA-2	April 25, 1962 14:00:34	File:S-IV-2.jpg	Template:Bulleted list
SA-3	November 16, 1962 17:45:02	File:S-IV-3.jpg	Template:Bulleted list
SA-4	March 28, 1963 20:11:55	File:S-IV-4.jpg	Template:Bulleted list
SA-5	January 29, 1964 16:25:01	File:S-IV-5.jpg	Template:Bulleted list
SA-6	May 28, 1964 17:07:00		Template:Bulleted list
SA-7	September 18, 1964 16:22:43	File:S-IV second stage of SA-7.webp	Template:Bulleted list
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		Template:Bulleted list
SA-10	July 30, 1965 13:00:00		Template:Bulleted list