Astronomy: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 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 66.7 kilonewtons (15,000 lb_f) of thrust for a total of about 400 kilonewtons (90,000 lb_f). 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		First test flight Block I Suborbital Range: 398 km (247 mi) Apogee: 1,365 km (848 mi) Apogee Mass: 52,500 kg (115,700 lb) Dummy S-IV and S-V stages
SA-2	April 25, 1962 14:00:34		Second test flight Block I Suborbital 86,000 kg (190,000 lb) of water released at apogee of 145 km (90 mi) as part of first Project Highwater flight
SA-3	November 16, 1962 17:45:02		Third test flight Block I Suborbital Dummy S-IV and S-V stages 86,000 kg (190,000 lb) of water released at apogee of 167 km (104 mi) as part of second and last Project Highwater flight
SA-4	March 28, 1963 20:11:55		Fourth test flight Block I Suborbital Dummy S-IV second stage and S-V third stage Apogee: 129 km (80 mi) Range: 400 km (250 mi)
SA-5	January 29, 1964 16:25:01	frameless	First live S-IV second stage First Block II First to orbit: 760 km × 264 km (472 mi × 164 mi) Mass: 17,550 kg (38,690 lb) Decayed 30 April 1966
SA-6	May 28, 1964 17:07:00		First Apollo boilerplate CSM launch Block II Orbit: 204 km × 179 km (127 mi × 111 mi) Mass: 17,650 kg (38,910 lb) Apollo BP-13 decayed 1 June 1964
SA-7	September 18, 1964 16:22:43	frameless	Second Apollo boilerplate CSM launch Block II Orbit: 203 km × 178 km (126 mi × 111 mi) Mass: 16,700 kg (36,800 lb)) Apollo BP-15 decayed 22 September 1964
SA-9	February 16, 1965 14:37:03	frameless	Third Apollo boilerplate CSM First Pegasus micrometeoroid satellite Orbit: 523 km × 430 km (325 mi × 267 mi) Mass: 1,450 kg (3,200 lb) 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 km × 467 km (369 mi × 290 mi) Mass: 1,450 kg (3,200 lb) 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 km × 535 km (352 mi × 332 mi) Mass: 1,450 kg (3,200 lb) Pegasus 3 decayed 4 August 1969 Apollo BP-9A decayed 22 November 1975

References

• Bilstein, Roger E. (1999). "6". Stages to Saturn: A Technological History of the Apollo/Saturn Launch. DIANE Publishing. ISBN 978-0-7881-8186-3. https://books.google.com/books?id=JnoZTbVLx0MC. Retrieved 2010-05-04. 
• NASA (April 1975). "Apollo Program Summary Report (Large file)". https://history.nasa.gov/alsj/APSR-JSC-09423.pdf.