S-IV

Schematics of the S-IV
Manufacturer	Douglas Aircraft Company
Country of origin	United States
Used on	Saturn I (stage 2)
General characteristics
Height	12.19 m (40 ft)
Diameter	5.49 m (18 ft)
Gross mass	50,576 kg (111,501 lb)
Propellant mass	45,359 kg (99,999 lb)
Empty mass	5,217 kg (11,502 lb)
Associated stages
Derivatives	S-IVB
Launch history
Status	Retired
Total launches	6
Successes (stage only)	6
First flight	January 29, 1964
Last flight	July 30, 1965
S-IV 100 series
Powered by	6 ×RL-10
Maximum thrust	400 kN (90,000 lbf)
Specific impulse	410 s (4.0 km/s)
Burn time	482 s
Propellant	LH2 /LOX

TheS-IV was thesecond stage of theSaturn Irocket used byNASA for early flights in theApollo program.

The S-IV was manufactured by theDouglas Aircraft Company and later modified by them to theS-IVB, a similar but distinct stage used on theSaturn IB andSaturn V rockets.^[1]

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 sixRL-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.^[2][3]

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 firstProject 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		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 Apolloboilerplate 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		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		Third Apollo boilerplate CSM FirstPegasus 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

• Apollo program
• Rocket stages
• Saturn I
• Saturn C-3
• Saturn C-2
• Saturn B-1

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