Editing Apollo program (section)

===Saturn I===
{{main|Saturn I}}
[[File:Apollo 7 launch2.jpg|thumb|right|upright=0.7|A Saturn IB rocket launches [[Apollo 7]], 1968]]

Saturn I, the first US heavy lift launch vehicle, was initially planned to launch partially equipped CSMs in low Earth orbit tests. The [[S-I]] first stage burned [[RP-1]] with liquid oxygen (LOX) oxidizer in eight clustered [[Rocketdyne H-1]] engines, to produce {{convert|1500000|lbf|kN|sigfig=3}} of thrust. The [[S-IV]] second stage used six liquid hydrogen-fueled [[Pratt & Whitney Rocketdyne|Pratt & Whitney]] [[RL-10]] engines with {{convert|90000|lbf|kN|sigfig=3}} of thrust. The [[S-V]] third stage flew inactively on Saturn I four times.<ref>[[#Dawson & Bowles|Dawson & Bowles 2004]], p. 85. See footnote 61.</ref>

The first four Saturn I test flights were launched from LC-34, with only the first stage live, carrying dummy upper stages filled with water. The first flight with a live S-IV was launched from LC-37. This was followed by five launches of [[Boilerplate (spaceflight)|boilerplate]] CSMs (designated [[AS-101]] through [[AS-105]]) into orbit in 1964 and 1965. The last three of these further supported the Apollo program by also carrying [[Pegasus (satellite)|Pegasus]] satellites, which verified the safety of the translunar environment by measuring the frequency and severity of [[micrometeorite]] impacts.{{sfn|Brooks|Grimwood|Swenson|1979|loc=Ch. 7.6: [http://www.hq.nasa.gov/office/pao/History/SP-4205/ch7-6.html "Portents for Operations"]}}

In September 1962, NASA planned to launch four crewed CSM flights on the Saturn I from late 1965 through 1966, concurrent with Project Gemini. The {{convert|22500|lb|kg|adj=on}} payload capacity<ref>{{cite book|url=http://www.alternatewars.com/SpaceRace/Saturn/ASD_II_Saturn_Launch_Vehicles-2-1964.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.alternatewars.com/SpaceRace/Saturn/ASD_II_Saturn_Launch_Vehicles-2-1964.pdf |archive-date=2022-10-09 |url-status=live|title=Apollo Systems Description|date=February 1, 1964|publisher=NASA|volume=II: Saturn Launch Vehicles|page=3|type=Technical Memorandum|id=NASA TM-X-881|access-date=August 1, 2013}}<!----Original URL for document on NTRS server: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710065502_1971065502.pdf----></ref> would have severely limited the systems which could be included, so the decision was made in October 1963 to use the uprated [[Saturn IB]] for all crewed Earth orbital flights.<ref>{{cite encyclopedia |url=http://www.astronautix.com/flights/apoosa11.htm |last=Wade |first=Mark |title=Apollo SA-11 |encyclopedia=Encyclopedia Astronautica |access-date=June 21, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120617193358/http://www.astronautix.com/flights/apoosa11.htm |archive-date=June 17, 2012 |df=mdy-all}}</ref>