Editing Apollo 4

{{Short description|First test flight of the Apollo Saturn V rocket}}
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{{Infobox spaceflight
| name                  = Apollo 4
| image                 = File:Apollo 4 Launch - GPN-2000-000044.jpg
| image_caption         = The first flight of a Saturn{{nbs}}V launch vehicle
| mission_type          = Uncrewed Earth orbital CSM flight ([[List of Apollo missions#Alphabetical mission types|A]])
| operator              = [[NASA]]
| COSPAR_ID             = 1967-113A (command and service modules)<br>1967-113B (S-IVB){{sfn|Orloff & Harland 2006|p=124}}
| SATCAT                = 3032
| mission_duration      = 8 hours, 36 minutes, 59{{nbs}}seconds
| orbits_completed      = 3
| spacecraft            = [[Apollo command and service module|Apollo CSM]]-017<br>Apollo LTA-10R
| manufacturer          = [[North American Rockwell]]
| launch_mass           = {{convert|81253|lb|kg|order=flip}}
| landing_mass          =
| launch_date           = {{start-date|November 9, 1967, 12:00:01|timezone=yes}}{{nbs}}UTC 
| launch_rocket         = [[Saturn V]] SA-501
| launch_site           = [[Kennedy Space Center|Kennedy]] [[Kennedy Space Center Launch Complex 39|LC-39]][[Kennedy Space Center Launch Complex 39A|A]] 
| landing_date          = {{end-date|November 9, 1967, 20:37:00|timezone=yes}}{{nbs}}UTC 
| landing_site          = North Pacific Ocean<br>{{Coord|30|06|N|172|32|W|type:event|name=Apollo 4 splashdown}}
| recovery_by           = {{USS|Bennington|CV-20|6}}
| orbit_epoch           = November 9, 1967<ref name=satcat>{{cite web|last=McDowell|first=Jonathan|title=Master Satellite List|url=http://planet4589.org/space/log/satcat.txt|publisher=Jonathan's Space Pages|access-date=March 23, 2014}}</ref>
| orbit_reference       = [[geocentric orbit|Geocentric]]
| orbit_regime          = [[Highly elliptical orbit]]
| orbit_periapsis       = {{convert|-204|km|nmi|sp=us}}
| orbit_apoapsis        = {{convert|18092|km|nmi|sp=us}}
| orbit_inclination     = 31.9 degrees
| orbit_period          = 314.58 minutes (initial)
| apsis                 = gee
| previous_mission      = [[Apollo 1]]
| next_mission          = [[Apollo 5]]
| programme             = [[Apollo program]]
}}

'''Apollo 4''' (November 9, 1967), also known as '''SA-501''', was the uncrewed first test flight of the [[Saturn&nbsp;V]] launch vehicle, the rocket that eventually took astronauts to the [[Moon]]. The [[space vehicle]] was assembled in the [[Vehicle Assembly Building]], and was the first to be launched from [[Kennedy Space Center]] (KSC) in Florida, ascending from [[Kennedy Space Center Launch Complex 39|Launch Complex 39]], where facilities built specially for the Saturn{{nbs}}V had been constructed.

Apollo 4 was an "all-up" test, meaning all rocket stages and spacecraft were fully functional on the initial flight, a first for [[NASA]]. It was the first time the [[S-IC]] first stage and [[S-II]] second stage flew. It also demonstrated the [[S-IVB]] third stage's first in-flight restart. The mission used a Block{{nbs}}I [[command and service module]] modified to test several key Block{{nbs}}II revisions, including its [[heat shield]] at simulated lunar-return velocity and angle.

The launch was planned for early 1967, but delayed to November{{nbs}}9 because of problems with various elements of the spacecraft and difficulties during pre-flight testing. Additional inspections were also required after a fire killed the [[Apollo&nbsp;1]] crew in January 1967. 

The mission splashed down in the Pacific Ocean slightly less than nine hours after launch, having achieved its objectives. NASA considered the mission a complete success, proving that the Saturn{{nbs}}V worked, an important step towards achieving the main objective of landing astronauts on the Moon, and bringing them back safely, before the end of the 1960s.

==Background==
In 1961 [[U.S. President]] [[John F. Kennedy]] proposed that his nation land an astronaut on the [[Moon]] by the end of the decade, with a safe return to Earth.<ref name = "mission overview">{{cite web|title=Apollo 11 Mission Overview|url=https://www.nasa.gov/mission_pages/apollo/missions/apollo11.html|date=December 21, 2017|access-date=February 14, 2019|publisher=[[NASA]]}}</ref> One of the early choices that had to be made to accomplish this goal was what launch vehicle to use. [[NASA]] decided on the Saturn{{nbs}}C-5 rocket, a three-stage launch vehicle based on rockets already in development. In 1962 this was approved by NASA, which contemplated an initial test launch in 1965 and a first crewed flight by 1967, leaving plenty of time to accomplish Kennedy's goal.{{sfn|Orloff & Harland 2006|pp=21–22}} In early 1963, NASA redesignated the C-5 as the [[Saturn&nbsp;V]].{{sfn|Bilstein 1996|p=60}}

After considerable debate within NASA, it was decided in late 1962 that lunar missions would have a "[[lunar orbit rendezvous]]" mode whereby the complete Apollo spacecraft would be propelled towards lunar orbit by the third stage of the launch vehicle, the [[S-IVB]]. Once in lunar orbit, the astronauts who would land would enter what was then known as the [[Lunar Excursion Module]], which would separate from the rest of the spacecraft, land, and after taking off again be discarded once the crew had transferred back. The remainder of the vehicle would then return to Earth.{{sfn|Orloff & Harland 2006|pp=25–26}} The launch facilities under development would not be sufficient for the new launch vehicle, and in 1962, NASA announced plans for a new complex on the Florida coast from which the Apollo lunar missions could be launched.{{sfn|Bilstein 1996|p=70}} This was dubbed the Launch Operations Center, but after [[Assassination of John F. Kennedy|Kennedy's assassination]] in November 1963 was renamed the [[John F. Kennedy Space Center]] (KSC).{{sfn|Orloff & Harland 2006|p=34}} Apollo{{nbs}}4 was the first flight from KSC, and the first using [[Launch Complex 39]] (LC-39) there, built to accommodate the Saturn{{nbs}}V.{{sfn|Press Kit|pp=30–31}}

The first three flights carrying Apollo equipment were launched using [[Saturn&nbsp;IB]]s. This smaller launch vehicle did not use the facilities at KSC, but issues resolved by Saturn{{nbs}}IB flights would be valid for those to be launched by the Saturn{{nbs}}V. Both the Saturn{{nbs}}IB and the Saturn{{nbs}}V would use a S-IVB, though the IB would use it as its second, final stage, rather than the third stage as on the Saturn{{nbs}}V. Thus, many of the [[flight qualification]]s for the payload the Saturn{{nbs}}V would carry could be resolved without having to expend one of the large launch vehicles.<ref>{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=The Apollo-Saturn IB Space Vehicle |chapter-url=https://www.hq.nasa.gov/office/pao/History/SP-4204/ch17-3.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.17-3.</ref> In addition to flight-qualifying the hardware, it was necessary to prove that the ground systems at KSC could successfully launch a Saturn V before risking the lives of astronauts on one.{{sfn|Saturn V evaluation|p=xxxviii}}

Three Saturn IB launches (in order of launch, [[AS-201]], [[AS-203]] and [[AS-202]]) took place in 1966; all were successful. According to Charles D. Benson and William B. Flaherty in their history of KSC, "The Apollo-Saturn{{nbs}}IB launches of 1966 represented important gains for NASA's launch team. [[LC-34]] and [[LC-37]], testbeds for automated [[Operations and Checkout Building|checkout]], were found wanting. In the twenty months between AS-201 and SA-501 [Apollo{{nbs}}4], KSC corrected the major automation problems. Without these trial and error advances, SA-501, the toughest launch in Apollo's history, would have been far more difficult."<ref>{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=More Launches of the Saturn IB |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch17-7.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.17-7.</ref>

==Delays==
[[File:Apollo-Saturn 501 Vehicle Preparations - GPN-2000-000956.jpg|thumb|right|alt=A rocket inside a high, narrow building with multiple levels surrounding it|Apollo 4 inside the [[Vehicle Assembly Building|VAB]]]]

In January 1965 Major General [[Samuel C. Phillips]], the [[Apollo Program]] Director, scheduled SA-501, the first test flight of the Saturn{{nbs}}V, for January 1967. This left little spare time for delay, especially since two additional Saturn{{nbs}}V launches were planned to follow in 1967.<ref>{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=500-F-A Dress Rehearsal |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch15-4.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.15-4.</ref> Many Apollo officials lacked confidence in the proposed launch date, and these misgivings proved accurate. After an explosion involving a liquid oxygen line flowing to LC-39, from which SA-501 was to be launched, there was a potential for a delay of several weeks.<ref name = "delay" />

[[North American Aviation]] was the contractor for both the [[S-II]] Saturn{{nbs}}V second stage, and the [[Apollo command and service module]] (CSM) spacecraft. NASA had been experiencing problems with North American's schedule, cost, and quality performance on both programs, severe enough that Phillips led a team to North American's facility in California in November and December 1965 to investigate matters, and recommend solutions to the program management problems. He published his findings in [[Phillips Report|a report to his supervisor]], [[George Mueller (NASA)|George Mueller]].<ref>{{cite web|url=https://history.nasa.gov/Apollo204/phillip1.html|title=NASA Apollo Mission Apollo-1-- Phillips Report|date=October 22, 2004 |publisher=[[NASA]] History Division}}</ref> Technicians found cracks in the S-II, delaying its test firings prior to acceptance by NASA. As North American worked to fix the S-II, parts of the rocket began to arrive at KSC, beginning with the S-IVB on August 14, 1966, (by [[Pregnant Guppy]] aircraft) and followed closely by the first stage [[S-IC]] on September 12 (by barge). A spool-shaped "spacer" that took the place of the S-II allowed NASA to stack the vehicle as its checkout proceeded in the [[Vehicle Assembly Building]] (VAB). With the S-II still not arrived by November 1966 (it had originally been planned for July), NASA planned January 1967 for its arrival, with launch three months later. The CSM arrived on December 24, 1966, with the S-II arriving on January 21, 1967. Last to arrive was the aft [[interstage]] (the structure between the first and second stages), on January 31.<ref name = "delay">{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=Delay after Delay after Delay |chapter-url=https://www.hq.nasa.gov/office/pao/History/SP-4204/ch19-3.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.19-3.</ref>

The [[Apollo 1]] fire on January 27, 1967, which killed three astronauts during a launch pad test, threw NASA's schedules into further question{{snd}}even though SA-501 was uncrewed, NASA officials wanted to closely examine its CSM. NASA had planned to restack the vehicle once this was done,<ref name = "delay" /> but instead the inspections that took place found a total of 1,407 errors in the spacecraft.<ref name="delay"/> Inspectors found many haphazardly routed and skinned wires, prime material for short circuits.<ref name = "fire">{{cite journal |last=Giblin |first=Kelly A. |date=Spring 1998 |title ='Fire in the Cockpit!' |journal=[[American Heritage of Invention & Technology]] |volume=13 |issue=4 |publisher=American Heritage Publishing |url=http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_46.shtml |archive-url=https://web.archive.org/web/20081120153024/http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_46.shtml |archive-date=November 20, 2008}}</ref>
[[File:Aerial view of Apollo 4 rollout.jpg|thumb|left|alt=A tall rocket on a platform is rolled out along a track towards a launch site|The Apollo 4 launch vehicle (right) is rolled out from the [[Vehicle Assembly Building]] (far left) past the Mobile Servicing Structure.]]

Other problems were discovered, such as an extra, out-of-place bolt in one of the [[Rocketdyne J-2|J-2]] engines; NASA was concerned not only with retrieving the surplus hardware, but also with discovering how it got there. A meeting in March 1967, with Phillips in attendance, disclosed twelve hundred problems with the Saturn{{nbs}}V, which the technicians proposed to deal with at the rate of eighty per day.{{sfn|Bilstein 1996|p=352}} While the CSM was undergoing repairs, the spacer was removed from the vehicle stack, and the S-II positioned. On May 24 it was announced that the S-II would be removed for inspection following the discovery of hairline cracks in another S-II then being constructed, this work being completed by mid-June, after which the CSM was also returned to the stack, the first time the launch vehicle and spacecraft had been fully assembled. It was rolled out to LC-39 on August 26, 1967,<ref name = "delay" /> where it was joined by the Mobile Servicing Structure that allowed access to the launch vehicle and spacecraft two days later, also transported by [[Crawler-transporter|crawler]].{{sfn|Press Kit|p=28}} This was the first time a NASA spacecraft had been assembled away from its launch site, something allowing protection from Florida's hot and humid climate for equipment and personnel.{{sfn|Press Kit|p=31}}

The [[Terminal countdown demonstration test|countdown demonstration test]] had been scheduled for September 20 but was soon rescheduled for the 25th and did not begin until the evening of the 27th. By October{{nbs}}2 another two days had been lost to delays, but by October{{nbs}}4 it reached launch minus 45 minutes. Then a computer failed, and the count, reset to minus 13 hours before launch, resumed on October 9. More computer and equipment problems appeared. By then, the launch team was exhausted and a two-day break was declared. The test was completed on October 13,<ref name = "delay 2" /> meaning that it took three weeks rather than the expectation of a week or slightly over. With world attention on the launch, NASA public relations head [[Julian Scheer]] brought the skeptical questions from the media as to whether Apollo{{nbs}}4 would ever fly to the attention of NASA Administrator [[James E. Webb]], leading to a heated meeting in which Webb said he would announce the launch date when he wanted to.{{sfn|Bilstein 1996|p=353}}

These difficulties provided the launch crew with valuable experience, but meant that Apollo{{nbs}}4 could not be launched at the earliest until November 7. A flight readiness review on October 19 cleared Apollo{{nbs}}4 for launch, assuming the remaining tests and modifications were satisfactorily completed.<ref name = "delay 2">{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=More Delays for AS-501 |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch19-5.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.19-5.</ref> Concerned about the potential for leaks in the [[Teflon]] seal rings and drain valves of the [[liquid oxygen]] tanks on board the vehicle due to the long time it had been sitting on the launch pad in the Florida sun, on November{{nbs}}2 Phillips postponed the launch until November{{nbs}}9.{{sfn|Bilstein 1996|p=353}}

==Objectives==
The purpose of Apollo 4 (together with the Saturn{{nbs}}V's other uncrewed test flight, Apollo{{nbs}}6) was to qualify the launch vehicle, the Apollo spacecraft, and the ground systems, for the crewed lunar landing missions that would follow. In addition to being the first flight of the Saturn{{nbs}}V, Apollo{{nbs}}4 marked the first flight for two of its stages: the S-IC first stage and the S-II second stage (the S-IVB had flown as part of the Saturn{{nbs}}IB).{{sfn|Saturn V evaluation|p=xxxviii}}{{sfn|Orloff & Harland 2006|p=75}}

Objectives for the Apollo 4 mission were to gain flight data on the Saturn{{nbs}}V and spacecraft structural integrity and mutual compatibility, including on flight loads and during the separations as each Saturn{{nbs}}V stage was exhausted and was discarded. NASA also wanted data on subsystem operations, including the emergency detection subsystem, and sought to evaluate the Apollo CM's [[heat shield]] under conditions simulating a return from a lunar mission.{{sfn|Press Kit|p=1}} NASA was also seeking to test the restart capability of the S-IVB in space.<ref name="photoAnal" /> These objectives would all be achieved.{{sfn|Orloff & Harland 2006|pp=127–137}}

==Equipment==
[[File:S67-36022.jpg|thumb|left|alt=A conical spacecraft is maneuvered atop a rocket|CSM-017 is moved into position.]]

Apollo 4 carried CSM-017, a Block{{nbs}}I design of the command and service modules meant for testing and for Apollo's early Earth orbit flights. Unlike the Block{{nbs}}II spacecraft which would go to the Moon, it lacked the capability to dock with a [[lunar module]] (LM).<ref name="Brooks Apollo 4" /> CSM-017 was made up of command module CM-017 and service module SM-020.<ref name = "cm" /> CM-017 was the second fully-functional CM to be delivered to NASA; the first, CM-012, was designated for Apollo{{nbs}}1, and was severely damaged in the fire.<ref name = "fire" /> SM-020 was originally to be used in CSM-020, slated for the second Saturn{{nbs}}V test, but this changed after SM-017, which was intended to be part of CSM-017, was damaged in an explosion and was scrapped.<ref name = "cm">{{cite web|title=Apollo/Skylab ASTP and Shuttle Orbiter Major End Items|date=March 1978|url=https://s3.documentcloud.org/documents/6473665/Apollo-Skylab-ASTP-and-Shuttle-Orbiter-Major-End.pdf|publisher=[[NASA]]|page=10, 15}}</ref>

Several significant Block II modifications were made to CSM-017 for certification purposes, since no Block{{nbs}}II spacecraft would fly without a crew.<ref name="Brooks Apollo 4">[[#Brooks|Brooks 1979]], [http://www.hq.nasa.gov/office/pao/History/SP-4205/ch9-5.html "''Apollo 4'' and Saturn V"] {{Webarchive|url=https://web.archive.org/web/20161107133918/http://www.hq.nasa.gov/office/pao/History/SP-4205/ch9-5.html |date=November 7, 2016 }}, Ch. 9-5</ref> These included upgrading the heat shield to Block{{nbs}}II standards, using a Block{{nbs}}II CM-to-SM umbilical connector, and installing Block{{nbs}}II-style VHF and [[Unified S-band|S-band]] antennae. Additionally, there were modifications to the CM's hatch.{{sfn|Press Kit|p=19}} The fact that the spacecraft hatch could not be readily opened in case of emergency had trapped the Apollo{{nbs}}1 astronauts in the fire that took their lives, and led to a redesign of the hatch. The new hatch was not scheduled to fly until the second Saturn{{nbs}}V test ([[Apollo&nbsp;6]]), but its seals were to be flight-qualified on Apollo{{nbs}}4{{snd}}the hatch window was replaced with a test panel simulating the seals and exterior heat shield. The heat shield was upgraded to Block{{nbs}}II standards since Apollo{{nbs}}4's high-speed re-entry into Earth's atmosphere was intended to simulate a return from the Moon.{{sfn|Press Kit|pp=2, 19–20}} Special equipment had been installed to allow Mission Control to operate the CSM's systems remotely, and there was a camera that would automatically take pictures out of one of the CM's windows on its final orbit.{{sfn|Press Kit|pp=18–19}} Since Apollo{{nbs}}4 carried no crew the CM lacked couches, controls and displays.<ref name = "register" />

A Lunar Module Test Article, LTA-10R, was carried, and remained inside the Spacecraft–LM Adapter, numbered as SLA-8, on the third stage of the Saturn{{nbs}}V throughout its flight. The LTA consisted of a flight-type descent stage lacking landing gear, with its fuel and oxidizer tanks containing a mixture of water, [[Ethylene glycol|glycol]], and [[freon]]. There was an ascent stage mockup atop it, made of aluminum with ballast, and having no flight systems. The SLA and LTA were instrumented to measure stress on them as the Saturn{{nbs}}V made its way to orbit.<ref name = "cm" />{{sfn|Press Kit|p=20}} LTA-10R would be destroyed when the S-IVB re-entered the atmosphere.{{sfn|Press Kit|p=3}}
[[File:Apollo 4 on the night before launch, Kennedy Space Center, Florida, 1967.jpg|thumb|right|upright|alt=Night view of a rocket on a launch pad|Apollo 4 on the launch pad]]

Apollo 4 was the first flight of a Saturn{{nbs}}V. At the time, it was the largest launch vehicle to ever attempt a flight.{{sfn|Reynolds 2002|pp=81–82}} This mission was the first time NASA used "all-up" testing, requiring that each stage of the launch vehicle work and that the vehicle carry a working spacecraft; a decision that goes back to late 1963.{{sfn|Cadbury 2006|p=274}} Mueller, the head of the NASA Office of Manned Space Flight at that time, was a [[Systems engineering|systems engineer]] who previously worked on military missile projects. He had recognized that all-up testing was successfully used to rapidly develop the Air Force's [[LGM-30 Minuteman|Minuteman ICBM]] program, and thought it could be used to meet Apollo's schedule.{{sfn|Murray & Cox 1989|pp=156–162}} In a 1963 memo he ordered that both the first Saturn{{nbs}}IB flight and the first Saturn{{nbs}}V flight be uncrewed, that each stage be fully functional, and that each carry a working spacecraft. The second flight of each type of rocket would also be an uncrewed test flight, and the third flight would be crewed.{{sfn|Bilstein 1996|p=349}} Previously, the way [[Wernher von Braun]]'s team at the [[Marshall Space Flight Center]] tested new rockets was by testing each stage incrementally.{{sfn|Murray & Cox 1989|pp=156–162}} The Saturn{{nbs}}V would be tested all at once, with all stages live and fully flight-worthy, including an Apollo CSM.{{sfn|Cadbury 2006|p=274}} This decision dramatically streamlined the program's test flight phase, eliminating four missions, but it required everything to work properly the first time.{{sfn|Cadbury 2006|p=274}} Apollo program managers had misgivings about all-up testing but agreed to it with some reluctance since incremental component tests would inevitably push the lunar landing mission past the 1970 goal.{{sfn|Neufeld 2007|pp=388–389, 400}}

==Mission numbering==
Apollo 4 was the first mission to fly under the official Apollo mission numbering scheme approved by Mueller on April 24, 1967; the planned first crewed flight, in preparation for which three astronauts had died, was retroactively designated Apollo{{nbs}}1 as the widows of the crew members had requested. Although three uncrewed Saturn{{nbs}}IB flights had already occurred, only two had contained an Apollo spacecraft (AS-203 carried only the aerodynamic nose cone). Mueller resumed the numbering sequence at Apollo{{nbs}}4, without designating an Apollo 2 or{{nbs}}3.<ref name="MarAprChron">{{cite book |last1=Ertel |first1=Ivan D. |last2=Newkirk |first2=Roland W. |last3=Brooks |first3=Courtney G. |title=The Apollo Spacecraft: A Chronology |url=http://www.hq.nasa.gov/office/pao/History/SP-4009/contents.htm#Volume%20IV |access-date=March 3, 2011 |volume=IV |year=1969–1978 |publisher=[[NASA]] |location=Washington, D.C. |id=NASA SP-4009 |oclc=23818 |lccn=69060008 |chapter=Part 1 (H): Preparation for Flight, the Accident, and Investigation: March 16 through April 5, 1967 |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4009/v4p1h.htm |display-authors=2 |archive-date=February 5, 2008 |archive-url=https://web.archive.org/web/20080205020128/http://www.hq.nasa.gov/office/pao/History/SP-4009/contents.htm#Volume%20IV |url-status=dead }}</ref><ref>{{cite web |url=https://history.nasa.gov/ap11ann/missions.htm |title=Apollo 11 30th Anniversary: Manned Apollo Missions |publisher=NASA History Office |year=1999 |access-date=March 3, 2011 |archive-url=https://web.archive.org/web/20110220232013/https://history.nasa.gov/ap11ann/missions.htm |archive-date=February 20, 2011 |url-status=live}}</ref>

==Public interest and media coverage==
VIPs swarmed to KSC in the days before the launch. Von Braun arrived on November 6, scheduled for an exclusive executive dinner and conference that evening. NASA executives, figures from industry, Congressional leaders and diplomats also came for the launch.{{sfn|Bilstein 1996|p=355}} Each NASA center involved had a list of VIP guests, as did NASA headquarters in Washington, and duplications were sorted out so each center's director could invite guests personally. They watched the launch from uncovered [[bleacher]]s near the VAB. NASA set up press headquarters in [[Cocoa Beach, Florida|Cocoa Beach]], where media representatives were accredited, and offered tours of KSC to visiting journalists, as well as a half-hourly shuttle service. NASA provided extensive telephone facilities for the media at the press site near LC-39, at their expense. KSC workers and their dependents watched the launch from near their work assignments.<ref name = "moonport vip">{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=Press, VIPs, Tourists, Dependents |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch19-7.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.19-7.</ref> In addition, 43 employees of contractors who had performed in an exemplary manner were selected as "Manned Flight Awareness" honorees, given a VIP tour of KSC, a social evening in which six astronauts participated, and a view of the launch.<ref name = "moonport launch">{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=September 28, 2021 |year=1978 |publisher=NASA |id=NASA SP-4204 |chapter=The Launch of Apollo 4 |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch19-6.html |url-status=dead |archive-date=January 23, 2008 |archive-url=https://web.archive.org/web/20080123133438/https://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html }} Ch.19-6.</ref>

Apollo 4, being the first flight of the Saturn{{nbs}}V, gained intense media coverage, and writers struggled to convey to the public the size of the launch vehicle, stating that it would tower well over the [[Statue of Liberty]] and be thirteen times as heavy. North American, in a handout to the media, noted that the 3000-ton Saturn{{nbs}}V comfortably outweighed a "good-sized navy [[destroyer]]".{{sfn|Bilstein 1996|p=354}} On the day before launch, Mueller, Phillips, von Braun, Deputy Administrator [[Robert C. Seamans]] and Kennedy Space Center Director [[Kurt Debus]]<ref>{{cite web|title=Apollo 4 pre-launch press conference|publisher=[[NASA]]|date=November 8, 1967|url=https://uah.contentdm.oclc.org/digital/collection/p16608coll1/id/8428/|access-date=October 15, 2021|archive-date=January 19, 2022|archive-url=https://web.archive.org/web/20220119052603/https://uah.contentdm.oclc.org/digital/collection/p16608coll1/id/8428/|url-status=dead}}</ref> held an outdoor press conference for more than a thousand journalists, including some from the [[Soviet Union]], with the Saturn{{nbs}}V in the background.{{sfn|Seamans 2005|pp=78–80}}

==Launch and flight==
{{quote box | align = right | width = 24em | salign = right
| quote = Our building's shaking! The roar is terrific! The building's shaking! This big glass window is shaking. We're holding it with our hands! Look at that rocket go! Into the clouds at 3,000 feet! The roar is terrific! Look at it going! You can see it. Part of our roof has come in here.| source = —[[Walter Cronkite]], November 9, 1967<ref name = "register" >{{cite news|last=Speed|first=Richard|title='That roar is terrific ... look at that rocket go!' It's been 52 years since first Saturn V left the pad|newspaper=The Register|url=https://www.theregister.com/2019/11/11/apollo_4/|date=November 11, 2019|access-date=September 5, 2021}}</ref>{{sfn|Brinkley 2012|p=369}}}}

On November 6, 1967, at 10:30{{nbs}}pm [[Eastern Standard Time (North America)|EST]] (03:30 November{{nbs}}7 [[UTC]]),{{sfn|Orloff & Harland 2006|p=137}} the {{frac|56|1|2}}-hour countdown sequence began with propellant loading. In total there were 89 trailer-truck loads of liquid oxygen, 28 trailer loads of [[LH2]] (liquid hydrogen), and 27 rail cars of [[RP-1]] (highly refined [[kerosene]]). This time the problems encountered were few and minor,<ref name = "moonport launch" /> and did not delay the launch due to the use of built-in holds in the countdown, during which time accumulated delays were made good.{{sfn|Orloff & Harland 2006|p=122}}

Apollo 4 launched on November{{nbs}}9 at 7:00{{nbs}}am EST (noon UTC). Eight seconds before liftoff, the five [[F-1 (rocket engine)|F-1]] engines ignited, sending tremendous amounts of noise across Kennedy Space Center. Even though the launch pads at LC-39 were more than five kilometers (three miles) from the Vehicle Assembly Building, the [[sound pressure]] was much stronger than expected and buffeted the VAB, Launch Control Center and press buildings. Dust was dislodged from the ceiling of the Launch Control Center and formed a layer on the consoles of mission controllers.<ref>{{cite news|url=https://timesmachine.nytimes.com/timesmachine/1967/11/10/90414376.pdf|title= Saturn V places Apollo in Orbit in Smooth Test|first=John Noble| last= Wilford|authorlink=John Noble Wilford|work=The New York Times|date=November 10, 1967|access-date=February 22, 2021}}</ref> William Donn of [[Columbia University]] described the blast as one of the loudest noises, natural or artificial, in human history, excepting nuclear explosions.{{sfn|Seamans 2005|p=80}} CBS's commentator, [[Walter Cronkite]], and producer [[Jeff Gralnick]] put their hands on their trailer's observation window to stop it from shattering as ceiling tiles fell from above. Cronkite found Apollo{{nbs}}4 to be the most frightening space mission he covered.{{sfn|Brinkley 2012|p=368}}
[[File:Activity in the Mission Control Room during launch of Apollo 4.jpg|thumb|left|alt=Rows of men at consoles watching screens|Mission controllers watch Apollo{{nbs}}4 climb to orbit.]]

The launch placed the S-IVB and CSM into a nearly circular {{convert|100|nmi|km|adj=on|order=flip|sp=us}} orbit, a nominal parking orbit that would be used on the lunar missions. After two orbits, in a simulation of the [[trans-lunar injection]] burn that would take later Apollo missions towards the Moon,{{sfn|Orloff & Harland 2006|p=126}} the S-IVB's first in-space re-ignition put the spacecraft into an elliptical orbit with an apogee of {{convert|9297|nmi|km|0|order=flip|sp=us}} and a perigee deliberately aimed {{convert|45.7|nmi|km|order=flip|sp=us}} below the Earth's surface; this would ensure both a high-speed [[Atmospheric entry|atmospheric re-entry]] of the command module, and destruction after re-entry of the S-IVB. Shortly after this burn, the CSM separated from the S-IVB and fired its service module engine to adjust the apogee to {{convert|9769|nmi|km|0|order=flip|sp=us}}. After passing apogee, the service module engine fired again for 281 seconds to increase re-entry speed to {{convert|36639|ft/s|m/s|order=flip|sp=us}}, at an altitude of {{convert|400000|ft|km|order=flip|sp=us}} and a flight path angle of −6.93 degrees, simulating conditions on a return from the Moon.{{sfn|Orloff & Harland 2006|pp=126–127}}

The CM landed approximately {{convert|8.6|nmi|km|0}} from the target landing site northwest of [[Midway Atoll|Midway Island]] in the North Pacific Ocean. Its descent was visible from the deck of the aircraft carrier {{USS|Bennington|CV-20|6}}, the prime recovery ship, which within two hours had recovered it and one of its parachutes, the first time an Apollo parachute had been recovered for inspection. The spacecraft was brought to Hawaii for deactivation, after which it was taken to North American's facility in [[Downey, California]], for post-flight analysis.{{sfn|Orloff & Harland 2006|p=127}}

==Onboard cameras==
[[File:Separation of Rocket Stages During Apollo 4.webm |thumbtime=2:29 |thumb |right |200px |alt=Two cameras captured the staging event; one clip is shown.  The first stage falls away, followed by the [[Adapter (rocketry)|interstage ring]]. |Two cameras captured the staging event; one clip is shown.  The first stage falls away, followed by the [[Adapter (rocketry)|interstage ring]].]]
Two motion-picture cameras were aboard Apollo{{nbs}}4. These were mounted on the Saturn{{nbs}}V so as to capture the separation of the first stage and interstage from the launch vehicle. They would then be ejected, descend to the Atlantic Ocean in pods with parachutes and radio beacons, and be recovered about {{convert|470|nmi|km|order=flip|sp=us}} downrange of KSC.{{sfn|Press Kit|p=12}} 

[[File:AS4-1-410HR.jpg|right|thumb|alt=Earth, photographed from Apollo 4|Earth photographed with the command module camera]]
The command module contained an automatic [[Medium format (film)|70{{nbs}}mm film]] camera which captured photographs of almost the entire Earth. For a period of two hours and thirteen minutes as the craft approached and passed its [[apogee]], a total of 755 color images were taken through the Command Pilot's (left-hand) forward-looking window, at altitudes ranging from {{convert|7295|to|9769|nmi|km|sp=us|order=flip}}. These were the color images taken from the highest altitude at that time. The photographs were not of sufficient resolution to obtain detailed scientific data, but were still of interest to those involved in the [[Earth sciences]].<ref name="photoAnal">{{cite book |last=Dornbach |first=John E. |title=Analysis of Apollo AS-501 Mission Earth Photography |url=http://apollo.sese.asu.edu/SUPPORT_DATA/ap04_index.pdf |access-date=July 8, 2013 |date=February 1968 |publisher=[[Lyndon B. Johnson Space Center|Manned Spacecraft Center]], NASA |location=Houston, TX |id=NASA TM X-58015}}</ref><ref>{{cite web|publisher=[[The Planetary Society]]|first=Jason|last= Davis|date=May 23, 2018|title=The curious case of the Apollo 4 Earth images|access-date=September 7, 2021|url=https://www.planetary.org/articles/20180522-apollo-4-images}}</ref>

==Aftermath, assessment and spacecraft location==
{{quote box | align = right | width = 24em | salign = right
| quote = Technically, managerially, and psychologically, Apollo{{nbs}}4 was an important and successful mission, especially in view of the number of firsts it tackled. It was the first flight of the first and second stages of the Saturn{{nbs}}V (the S-IVB stage had flown on the Saturn{{nbs}}IB launch vehicles), the first launch of the complete Saturn{{nbs}}V, the first restart of the S-IVB in orbital flight, the first liftoff from Complex 39, the first flight test of the Block{{nbs}}II command module heatshield, the first flight of even a simulated lunar module, and so on. The fact that everything worked so well and with so little trouble gave NASA a confident feeling, as Phillips phrased it, that "Apollo [was] on the way to the moon."| source = —Courtney G. Brooks, James M. Grimwood and Loyd S. Swenson, ''Chariots for Apollo: A History of Manned Lunar Spacecraft'' (1979)<ref name="Brooks Apollo 4" />}}

All Apollo 4 launch vehicle and spacecraft systems performed satisfactorily. On the climb to orbit, each of the Saturn{{nbs}}V's three stages burned for slightly longer than expected. This left the craft in an orbit roughly one kilometer higher than expected, something well within tolerance. A burn eleven seconds longer than planned meant that the CM entered the Earth's atmosphere slightly faster and at a shallower angle than planned, but still within tolerance. This discrepancy happened not because of the performance of the guidance system (which was exemplary), but because the burn had been controlled from Earth. The CM's environmental control system kept the ship's cabin within acceptable temperatures and pressures throughout the mission, increasing by only {{convert|5.6|C-change|0}} during atmospheric entry.{{sfn|Orloff & Harland 2006|pp=124–127}}{{sfn|Press Kit|p=43}}

President [[Lyndon Johnson]] described the launch, "The whole world could see the awesome sight of the first launch of what is now the largest rocket ever flown. This launching symbolizes the power this nation is harnessing for the peaceful exploration of space."{{sfn|Seamans 2005|p=80}} Von Braun spoke of the mission as "an expert launching all the way through, from lift-off exactly on time to performance of every single stage".<ref name ="moonport launch" /> In his history of the Saturn{{nbs}}V, Roger E. Bilstein wrote that "the flawless mission of Apollo{{nbs}}4 elated the entire NASA organization; everyone looked ahead with buoyant spirits."{{sfn|Bilstein 1996|p=359}} Mueller stated that Apollo{{nbs}}4 dramatically increased the confidence of many and showed it should be possible for astronauts to land on the Moon by mid-1969.<ref name = "moonport launch" />

Apollo 6, the second flight of the Saturn{{nbs}}V, was launched on April 4, 1968. Although the Saturn{{nbs}}V's stages gave more trouble than on Apollo{{nbs}}4 (the mission experienced [[pogo oscillation]] during its first stage and had an early second-stage engine shutdown),{{sfn|Orloff & Harland 2006|pp=153–154}} it was decided that a third uncrewed flight was unnecessary. The Saturn{{nbs}}V flew with a crew for the first time on [[Apollo&nbsp;8]].{{sfn|Orloff & Harland 2006|pp=55–59}} A Saturn{{nbs}}V launched astronauts into space, and (except for [[Apollo 9]]) towards the Moon, on each of the Apollo missions that followed.{{sfn|Orloff & Harland 2006|pp=572–573}}

In January 1969 CM-017 was transferred to the [[Smithsonian Institution]].<ref name="Smithsonian-1967">{{cite web|url=https://airandspace.si.edu/collection-objects/command-module-apollo-4/nasm_A19700254000|title=Command Module, Apollo 4|website=airandspace.si.edu|access-date=July 19, 2020}}</ref> As of 1978, it was on display at the [[North Carolina Museum of Life and Science]].<ref name = "hardware">{{cite web|title=Apollo/Skylab ASTP and Shuttle Orbiter Major End Items|date=March 1978|url=https://s3.documentcloud.org/documents/6473665/Apollo-Skylab-ASTP-and-Shuttle-Orbiter-Major-End.pdf|publisher=[[NASA]]|page=15}}</ref> The CM was subsequently put on public display at NASA's [[Stennis Space Center]], where it remained until 2017. It is currently on display at Stennis Space Center's visitor center, the Infinity Science Center, in [[Pearlington, Mississippi]].<ref name="space-2017">{{cite web|first=Robert Z.|last=Pearlman|date=October 31, 2017|url=https://www.space.com/38626-apollo-4-lands-infinity-science-center.html|title=Apollo 4 Capsule From 1st Saturn V Launch Lands at Infinity Science Center|website=www.space.com|access-date=July 19, 2020}}</ref>

==References==
===Citations===
{{Reflist|2}}

===Bibliography===
{{Refbegin|2}}
*{{cite book|title=Apollo 4 Press Kit|publisher=NASA|location=Washington, D.C.|year=1968|url=http://libarchstor2.uah.edu/digitalcollections/items/show/10722|ref={{sfnRef|Press Kit}}}}
*{{cite book |title=Saturn V Launch Vehicle Flight Evaluation Report – AS-501 Apollo 4 Mission |url=http://klabs.org/history/history_docs/jsc_t/apollo_2004_Saturn_v.pdf |access-date=July 8, 2013 |date=January 15, 1968 |publisher=[[NASA]] |location=[[Marshall Space Flight Center|George C. Marshall Space Flight Center]] |id=MPR-SAT-FE-68-1 |archive-url=https://web.archive.org/web/20160303230517/http://klabs.org/history/history_docs/jsc_t/apollo_2004_Saturn_v.pdf |archive-date=March 3, 2016 |url-status=dead |ref={{sfnRef|Saturn V evaluation}} }}
*{{cite book |last1=Benson |first1=Charles D. |last2=Faherty |first2=William Barnaby |title=Moonport: A History of Apollo Launch Facilities and Operations |url=http://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |access-date=July 8, 2013 |series=NASA History Series |year=1978 |publisher=Scientific and Technical Information Office, [[NASA]] |location=Washington, D.C. |lccn=77029118 |id=NASA SP-4204 |ref=Benson & Faherty }}
*{{cite book |last=Bilstein |first=Roger E. |title=Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles |url=https://history.nasa.gov/SP-4206/sp4206.htm |access-date=July 8, 2013 |series=NASA History Series |year=1996 |publisher=NASA History Office, NASA |location=Washington, D.C. |isbn=978-0-16-048909-9 |lccn=97149850 |id=NASA SP-4206 |ref={{sfnRef|Bilstein 1996}} }}
*{{cite book |last=Brinkley |first=Douglas |author-link=Douglas Brinkley |year=2012 |title=Cronkite |location=New York |publisher=[[HarperCollins]] |isbn=978-0-06-137426-5 |lccn=2011051467 |url=https://archive.org/details/isbn_9780061374265 |ref={{sfnRef|Brinkley 2012}} }}
*{{cite book |last1=Brooks |first1=Courtney G. |last2=Grimwood |first2=James M. |last3=Swenson |first3=Loyd S. Jr. |title=Chariots for Apollo: A History of Manned Lunar Spacecraft |url=http://www.hq.nasa.gov/office/pao/History/SP-4205/cover.html |access-date=July 8, 2013 |series=NASA History Series |year=1979 |publisher=Scientific and Technical Information Office, NASA |location=Washington, D.C. |lccn=79001042 |id=NASA SP-4205 |ref=Brooks |archive-date=October 20, 2015 |archive-url=https://web.archive.org/web/20151020095653/http://www.hq.nasa.gov/office/pao/History/SP-4205/cover.html |url-status=dead }}
*{{cite book |last=Cadbury |first=Deborah |title=Space Race: The Epic Battle Between America and the Soviet Union for Dominion of Space |url=https://archive.org/details/spaceraceepicbat00cadb |url-access=registration |year=2006 |publisher=HarperCollins |location=New York |isbn=978-0-06-084553-7 |lccn=2005052693 |ref={{sfnRef|Cadbury 2006}} }}
*{{cite book |last1=Murray |first1=Charles A. |author-link=Charles Murray (political scientist) |last2=Cox |first2=Catherine Bly Cox |title=Apollo: The Race to the Moon |edition=1st Touchstone |year=1989 |publisher=Simon & Schuster |location=New York |isbn=978-0-671-70625-8 |lccn=89006333 |ref={{sfnRef|Murray & Cox 1989}}}}
*{{cite book |last=Neufeld |first=Michael J. |title=Von Braun: Dreamer of Space, Engineer of War |year=2007 |publisher=[[Alfred A. Knopf]] |location=New York |isbn=978-0-307-26292-9 |url=https://archive.org/details/vonbraundreamero00neuf |ref={{sfnRef|Neufeld 2007}} }}
*{{cite book|last1=Orloff|first1=Richard W.|last2=Harland|first2=David M.|author-link2=David M. Harland|title=Apollo: The Definitive Sourcebook|year=2006|publisher=Praxis Publishing Company|location=Chichester, UK|isbn=978-0-387-30043-6|ref={{sfnRef|Orloff & Harland 2006}}}}
*{{cite book |last=Reynolds |first=David West |title=Apollo: The Epic Journey to the Moon |edition=1st |year=2002 |publisher=[[Harcourt (publisher)|Harcourt]] |location=New York |isbn=0-15-100964-3 |lccn=2001051930 |ref={{sfnRef|Reynolds 2002}} |url=https://archive.org/details/apolloepicjourne00reyn }}
*{{cite book|last=Seamans|first=Robert C.|authorlink=Robert C. Seamans|title=Project Apollo: The Tough Decisions|isbn=978-0-16-074954-4|year=2005|publisher=[[NASA]]|location=Washington, DC|ref={{sfnRef|Seamans 2005}}}}
{{Refend}}

==External links==
{{Commons}}
*[https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1967-113A "Apollo 4"] at NASA's [[National Space Science Data Center]]
*{{Internet Archive short film | JSC_0457_Apollo4_and_Apollo5_Missions.wmv | The Apollo 4 Mission and The Apollo 5 Mission}}

{{Apollo program}}
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{{Orbital launches in 1967}}
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[[Category:Apollo program missions|Apollo 04]]
[[Category:1967 in the United States]]
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[[Category:Spacecraft launched by Saturn rockets]]
[[Category:Successful space missions]]