View source for S-IV

{{Short description|Upper stage for NASA's Saturn I rocket}}
{{Infobox rocket stage
|name = S-IV
|image = S-IV rocket stage.jpg
|caption = Schematics of the S-IV
|manufacturer = [[Douglas Aircraft Company]]
|country = United States
|rockets = [[Saturn I]] (stage 2)
|height = {{cvt|12.19|m|0}}
|diameter = {{cvt|5.49|m|0}}
|mass = {{cvt|50,576|kg}}
|propmass = {{cvt|45,359|kg|0}}
| empty         = {{cvt|5,217|kg|0}}
| status        = Retired
| launches      = 6
| success       = 6
| first         = January 29, 1964
| last          = July 30, 1965

{{Infobox rocket/stage
| name          = S-IV 100 series
|engines = 6 × [[RL-10 (rocket engine)|RL-10]]
|thrust = {{convert|400|kN|lbf|abbr=on}}
| SI            = {{Convert|410|isp|abbr=on}}
| burntime      = 482 s
| fuel          = [[LH2|LH<sub>2</sub>]] / [[Liquid oxygen|LOX]]
}}
|derivatives=[[S-IVB]]}}
The '''S-IV''' was the [[Multistage rocket|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">{{Harvnb|Bilstein|1999|loc=p. 157}}</ref>

The S-IV stage was a large LOX/LH<sub>2</sub>-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 [[RL10|RL-10A-3]] engines. Each one of the engines supplied {{convert|66.7|kN}} of thrust for a total of about {{convert|400|kN}}. The cryogenic LH<sub>2</sub> ([[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 LH<sub>2</sub> tank.  This saved up to 20% of structural weight.<ref name="stages2">{{Harvnb|Bilstein|1999|loc=pp. 166-168}}</ref><ref>{{Harvnb|Apollo Summary Report|1975|loc=p. 187}}</ref>
== Flight history ==
{{sticky header}}
{| class="wikitable sticky-header"
|+
!Mission serial number
!Launch date (UTC)
!Image
!Launch notes
|-
|[[SA-1 (Apollo)|SA-1]]
|October 27, 1961<br />15:06:04
|[[File:S-IV-1.jpg|frameless|150x150px]]
|{{Bulleted list
  | First test flight 
  | Block I 
  | Suborbital 
  | Range: {{cvt|398|km}} 
  | Apogee: {{cvt|1365|km}} 
  | Apogee Mass: {{cvt|52,500|kg}} 
  | Dummy S-IV and S-V stages
  }}
|-
|[[SA-2 (Apollo)|SA-2]]
|April 25, 1962<br />14:00:34
|[[File:S-IV-2.jpg|frameless|150x150px]]
|{{Bulleted list
  | Second test flight 
  | Block I 
  | Suborbital 
  | {{cvt|86,000|kg}} of water released at apogee of {{cvt|145|km}} as part of first [[Project Highwater]] flight
  }}
|-
|[[SA-3 (Apollo)|SA-3]]
|November 16, 1962<br />17:45:02
|[[File:S-IV-3.jpg|frameless|150x150px]]
|{{Bulleted list
  | Third test flight 
  | Block I 
  | Suborbital 
  | Dummy S-IV and S-V stages
  | {{cvt|86,000|kg}} of water released at apogee of {{cvt|167|km}} as part of second and last Project Highwater flight
  }}
|-
|[[SA-4 (Apollo)|SA-4]]
|March 28, 1963<br />20:11:55
|[[File:S-IV-4.jpg|frameless|150x150px]]
|{{Bulleted list
  | Fourth test flight 
  | Block I 
  | Suborbital 
  | Dummy S-IV second stage and S-V third stage 
  | Apogee: {{cvt|129|km}} 
  | Range: {{cvt|400|km}}
  }}
|-
|[[SA-5 (Apollo)|SA-5]]
|January 29, 1964<br />16:25:01
|[[File:S-IV-5.jpg|frameless]]
|{{Bulleted list
  | First live S-IV second stage 
  | First Block II 
  | First to orbit: {{cvt|760 x 264|km}} 
  | Mass: {{cvt|17,550|kg}} 
  | Decayed 30 April 1966
  }}
|-
|[[AS-101|SA-6]]
|May 28, 1964<br />17:07:00
|
|{{Bulleted list
  | First Apollo [[Boilerplate (spaceflight)|boilerplate]] CSM launch 
  | Block II 
  | Orbit: {{cvt|204 x 179|km}} 
  | Mass: {{cvt|17,650|kg}} 
  | Apollo BP-13 decayed 1 June 1964
  }}
|-
|[[AS-102|SA-7]]
|September 18, 1964<br />16:22:43
|[[File:S-IV second stage of SA-7.webp|frameless]]
|{{Bulleted list
  | Second Apollo boilerplate CSM launch 
  | Block II 
  | Orbit: {{cvt|203 x 178|km}} 
  | Mass: {{cvt|16,700|kg}}) 
  | Apollo BP-15 decayed 22 September 1964
  }}
|-
|[[AS-103|SA-9]]
|February 16, 1965<br />14:37:03
|[[File:Second Stage for SA-9.jpg|frameless]]
|{{Bulleted list
  | Third Apollo boilerplate CSM 
  | First [[Pegasus (satellite)|Pegasus]] micrometeoroid satellite 
  | Orbit: {{cvt|523 x 430|km}} 
  | Mass: {{cvt|1,450|kg}} 
  | Pegasus 1 decayed 17 September 1978 
  | Apollo BP-26 decayed 10 July 1985
  }}
|-
|[[AS-104|SA-8]]
|May 25, 1965<br />07:35:01
|
|{{Bulleted list
  | Fourth Apollo boilerplate CSM Only night launch 
  | Second Pegasus micrometeoroid satellite 
  | Orbit: {{cvt|594 x 467|km}} 
  | Mass: {{cvt|1,450|kg}} 
  | Pegasus 2 decayed 3 November 1979 
  | Apollo BP-16 decayed 8 July 1989
  }}
|-
|[[AS-105|SA-10]]
|July 30, 1965<br />13:00:00
|
|{{Bulleted list
  | Third Pegasus micrometeoroid satellite
  | Orbit: {{cvt|567 x 535|km}}
  | Mass: {{cvt|1,450|kg}}
  | Pegasus 3 decayed 4 August 1969
  | Apollo BP-9A decayed 22 November 1975
  }}
|}

== References ==
{{reflist}}
{{refbegin}}
*{{cite book|title=Stages to Saturn: A Technological History of the Apollo/Saturn Launch |url=https://books.google.com/books?id=JnoZTbVLx0MC|author=Bilstein, Roger E.|publisher=DIANE Publishing |year=1999|accessdate=2010-05-04|chapter=6| isbn=978-0-7881-8186-3 |ref=CITEREFBilstein1999}}
*{{cite web | url = https://history.nasa.gov/alsj/APSR-JSC-09423.pdf | title =  Apollo Program Summary Report (Large file) | author = NASA |date=April 1975 |ref=CITEREFApollo_Summary_Report1975}}
{{refend}}

{{Upper stages}}

[[Category:Apollo program]]
[[Category:Rocket stages]]
[[Category:Saturn I]]
[[Category:Saturn C-3]]
[[Category:Saturn C-2]]
[[Category:Saturn B-1]]