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)	Launch notes
SA-1	October 27, 1961 15:06:04	File:S-IV-1.jpg First test flight. Block I. Suborbital. Range: 398 km. Apogee: 136.5 km. Apogee Mass: 115,700 lb (52,500 kg). Dummy S-IV and S-V stages.
SA-2	April 25, 1962 14:00:34	File:S-IV-2.jpg Second test flight. Block I. Suborbital. 86,000 kg water released at apogee of 145 km as part of Project Highwater. Dummy S-IV and S-V stages.
SA-3	November 16, 1962 17:45:02	File:S-IV-3.jpg Third test flight. Block I. Suborbital. 86,000 kg water released at apogee of 167 km. Dummy S-IV and S-V stages. Second and last Project Highwater flight.
SA-4	March 28, 1963 20:11:55	File:S-IV-4.jpg Fourth test flight. Block I. Suborbital. Dummy S-IV second stage and S-V third stage. Apogee: 129 km. Range: 400 km.
SA-5	January 29, 1964 16:25:01	File:S-IV-5.jpg First live S-IV second stage. First Block II. First to orbit: 760 x 264 km. Mass: 38,700 lb (17,550 kg). Decayed 30 April 1966.
SA-6	May 28, 1964 17:07:00	First Apollo boilerplate CSM launch. Block II. Orbit: 204 x 179 km. Mass: 38,900 lb (17,650 kg). Apollo BP-13 decayed 1 June 1964.
SA-7	September 18, 1964 16:22:43	File:S-IV second stage of SA-7.webp Second Apollo boilerplate CSM launch. Block II. Orbit: 203 x 178 km. Mass: 36,800 lb (16,700 kg). Apollo BP-15 decayed 22 September 1964.
SA-9	February 16, 1965 14:37:03	File:Second Stage for SA-9.jpg Third Apollo boilerplate CSM. First Pegasus micrometeoroid satellite. Orbit: 523 x 430 km. Mass: 3,200 lb (1,450 kg). Pegasus 1 decayed 17 September 1978. Apollo BP-26 decayed 10 July 1985.
SA-8	May 25, 1965 07:35:01	Fourth Apollo boilerplate CSM. Only night launch. Second Pegasus micrometeoroid satellite. Orbit: 594 x 467 km. Mass: 3,200 lb (1,450 kg). Pegasus 2 decayed 3 November 1979. Apollo BP-16 decayed 8 July 1989.
SA-10	July 30, 1965 13:00:00	Third Pegasus micrometeoroid satellite. Orbit: 567 x 535 km. Mass: 3,200 lb (1,450 kg). Pegasus 3 decayed 4 August 1969. Apollo BP-9A decayed 22 November 1975.

References

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