View source for Apollo 8

{{Short description|First crewed space mission to orbit the Moon}}
{{Featured article}}
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{{Use American English|date=January 2014}}
{{Use mdy dates|date=April 2024}}
{{Infobox spaceflight
| name               = Apollo 8
| image              = NASA-Apollo8-Dec24-Earthrise.jpg
| image_caption      = ''[[Earthrise]]''<br />Taken from Apollo{{nbsp}}8 by [[William Anders]]<ref name="NYT-20181221" /><ref name="NYT-20181224a" /><ref name="NYT-20181224b" />
| image_alt          = A black sky with a grey, cratered lunar horizon. A small blue Earth with scattered white clouds is just above the horizon, with about two-thirds of the Earth lit by the Sun and the remainder in darkness.
| insignia           = Apollo-8-patch.png
| mission_type       = Crewed lunar orbital CSM flight ([[List of Apollo missions#Alphabetical mission types|C']])
| operator           = [[NASA]]
| mission_duration   = 6{{nbsp}}days, 3{{nbsp}}hours, 42{{nbsp}}seconds<ref>{{Cite web |date=July 9, 2009 |title=Apollo 8 |url=https://www.nasa.gov/mission_pages/apollo/missions/apollo8.html |access-date=November 25, 2018 |publisher=NASA}}</ref>
| spacecraft         = {{Unbulleted list
 |[[Apollo command and service module|Apollo CSM]]-103
 |Apollo LTA-B
}}
| manufacturer       = [[North American Rockwell]]
| launch_mass        = {{Unbulleted indent list
 |CSM: {{convert|63650|lb|kg|order=flip|abbr=on}}<ref name="PressKit">{{Cite web |date=December 15, 1968 |title=Apollo 8 Press Kit |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690003059_1969003059.pdf |url-status=live |archive-url=https://ghostarchive.org/archive/20221009/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690003059_1969003059.pdf |archive-date=October 9, 2022 |access-date=June 28, 2013 |publisher=NASA |pages=33–34 |type=Press kit |id=Release No. 68-208}} The spacecraft mass at launch includes the CM and SM, but excludes the {{convert|8900|lb|kg|order=flip}} Launch Escape System (LES), which was discarded before reaching Earth orbit.</ref>
 |CM:{{convert|12392|lb|kg|order=flip|abbr=on}}
 |SM:{{convert|51258|lb|kg|order=flip|abbr=on}}
 |SC/LM Adapter (jettisoned; connects LTA to CSM; not part of the CSM craft): {{convert|4060|lb|kg|order=flip|abbr=on}}<ref name="prelaunch">{{Cite web |date=December 17, 1968 |title=Pre-Launch Mission Operation Report No. M-932-68-08 |url=https://history.nasa.gov/afj/ap08fj/pdf/a08-prelaunch-rep.pdf |url-status=live |archive-url=https://ghostarchive.org/archive/20221009/https://history.nasa.gov/afj/ap08fj/pdf/a08-prelaunch-rep.pdf |archive-date=October 9, 2022 |access-date=February 12, 2019 |publisher=NASA |page=30 |type=Memorandum |id=M-932-68-08}}</ref>
 |LTA (not part of CSM; fixed to rocket): {{convert|19900|lb|kg|order=flip|abbr=on}}<ref>{{Cite web |date=February 1969 |title=Apollo 8 Mission Report |url=https://history.nasa.gov/ap08fj/pdf/a08-missionreport.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130302223118/http://history.nasa.gov/ap08fj/pdf/a08-missionreport.pdf |archive-date=March 2, 2013 |access-date=June 28, 2013 |publisher=NASA |at=p. A-14 |id=MSC-PA-R-69-1}} The mass for LTA-B was less than that of a flying LM, because it was essentially a boilerplate descent stage. A fully loaded, flight-ready LM, like the ''Eagle'' from Apollo 11, had a mass of {{convert|33278|lb|kg|order=flip|abbr=on}}, including propellants.</ref>
}}
| landing_mass       = {{convert|10977|lb|kg|order=flip|abbr=on}}
| launch_date        = {{start date text|December 21, 1968, 12:51:00|timezone=yes}}{{nbsp}}[[UTC]] (7:51&nbsp;am&nbsp;[[Eastern Time Zone (North America)|EST]])<ref>{{Cite web |title=Apollo 8 |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-118A |access-date=January 9, 2023 |publisher=[[NASA Space Science Data Coordinated Archive]]}}</ref>
| launch_rocket      = [[Saturn V]] SA-503<ref name="serialnote" group="n">Serial numbers were initially assigned by the [[Marshall Space Flight Center]] in the format "SA-5xx" (for Saturn-Apollo). By the time the rockets achieved flight, the [[Lyndon B. Johnson Space Center|Manned Spacecraft Center]] started using the format "AS-5xx" (for Apollo-Saturn).</ref>
| launch_site        = [[Kennedy Space Center|Kennedy]], [[Kennedy Space Center Launch Complex 39A|LC-39A]]
| landing_date       = {{end date text|December 27, 1968, 15:51:42|timezone=yes}}&nbsp;UTC (5:51:42&nbsp;am&nbsp;[[Hawaii Standard Time|HST]])<ref name="MissionReport">{{Cite web |date=February 1969 |title=Apollo 8 Mission Report |url=http://www.hq.nasa.gov/alsj/a410/A08_MissionReport.pdf |url-status=dead |archive-url=https://web.archive.org/web/20161222031006/http://www.hq.nasa.gov/alsj//a410/A08_MissionReport.pdf |archive-date=December 22, 2016 |access-date=June 28, 2013 |publisher=NASA |at=p. 3-2 |id=MSC-PA-R-69-1}}</ref>
| landing_site       = North Pacific Ocean, southwest of [[Hawaii]], ({{Coord|8|8|N|165|1|W|type:event|name=Apollo 8 landing}})<ref name="MissionReport" />
| recovery_by        = {{USS|Yorktown|CV-10|6}}
| orbit_epoch        = December 21, 1968, ~13:02&nbsp;UTC
| orbit_reference    = 
| orbit_periapsis    = {{convert|99.57|nmi|km|disp=out|abbr=on|1}} (99.57&nbsp;[[Nautical mile|nmi]]; {{convert|99.57|nmi|mi|disp=out|abbr=on|1}})
| orbit_apoapsis     = {{convert|99.99|nmi|km|disp=out|abbr=on|1}} (99.99&nbsp;nmi; {{convert|99.99|nmi|mi|disp=out|abbr=on|1}})
| orbit_inclination  = 32.15°
| orbit_period       = 88.19 minutes
| orbit_rev_number   = 2
| apsis              = gee
|interplanetary      = 
 {{Infobox spaceflight/IP
   |type             = orbiter
   |object           = [[Moon|Lunar]]
   |orbits           = 10
   |component        = CSM
   |arrival_date     = December 24, 1968, 9:59:20&nbsp;UTC<ref>{{Cite web |date=February 1969 |title=Apollo 8 Mission Report |url=http://www.hq.nasa.gov/alsj/a410/A08_MissionReport.pdf |url-status=dead |archive-url=https://web.archive.org/web/20161222031006/http://www.hq.nasa.gov/alsj//a410/A08_MissionReport.pdf |archive-date=December 22, 2016 |access-date=May 8, 2015 |publisher=NASA |at=p. 3-1 |id=MSC-PA-R-69-1}}</ref>
   |departure_date   = December 25, 1968, 6:10:17&nbsp;UTC<ref name="MissionReport" />
<!--Orbit parameters, ONLY USE IF THE ABOVE ORBIT PARAMETERS SECTION DOESN'T APPLY TO THE TARGET-->
   |epoch            = December 24, 1968, ~02:30&nbsp;UTC
   |periapsis        = {{convert|59.7|nmi|km|disp=out|abbr=on|1}} (59.7&nbsp;nmi; {{convert|59.7|nmi|mi|disp=out|abbr=on|1}})
   |apoapsis         = {{convert|60.7|nmi|km|disp=out|abbr=on|1}} (60.7&nbsp;nmi; {{convert|60.7|nmi|mi|disp=out|abbr=on|1}})
   |inclination      = 12°
   |apsis            = selene
   |period           = 2 hours
 }}
| crew_size          = 3
| crew_members       = {{Unbulleted list
  | [[Frank Borman|Frank F. Borman II]]
  | [[Jim Lovell|James A. Lovell Jr.]]
  | [[William Anders|William A. Anders]]
  }}
| crew_callsign      = Apollo 8
| crew_photo         = Apollo8 Prime Crew.jpg
| crew_photo_caption = Left to right: [[William Anders|Anders]], [[Jim Lovell|Lovell]] and [[Frank Borman|Borman]]
| programme          = [[Apollo program]]
| previous_mission   = [[Apollo 7]]
| next_mission       = [[Apollo 9]]
}}

'''Apollo 8''' (December 21–27, 1968) was the first crewed [[spacecraft]] to leave [[Sphere of influence (astrodynamics)|Earth's gravitational sphere of influence]], and the first [[human spaceflight]] to reach the [[Moon]]. The crew orbited the Moon ten times without landing and then returned to Earth.<ref name="NYT-20181221">{{Cite news |last=Overbye |first=Dennis |author-link=Dennis Overbye |date=December 21, 2018 |title=Apollo 8's Earthrise: The Shot Seen Round the World—Half a century ago today, a photograph from the moon helped humans rediscover Earth. |url=https://www.nytimes.com/2018/12/21/science/earthrise-moon-apollo-nasa.html |url-access=limited |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2018/12/21/science/earthrise-moon-apollo-nasa.html |archive-date=January 1, 2022 |access-date=December 24, 2018 |work=[[The New York Times]]}}{{cbignore}}</ref><ref name="NYT-20181224a">{{Cite news |last=Boulton |first=Matthew Myer |last2=Heithaus |first2=Joseph |date=December 24, 2018 |title=We Are All Riders on the Same Planet—Seen from space 50 years ago, Earth appeared as a gift to preserve and cherish. What happened? |url=https://www.nytimes.com/2018/12/24/opinion/earth-space-christmas-eve-apollo-8.html |url-access=limited |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2018/12/24/opinion/earth-space-christmas-eve-apollo-8.html |archive-date=January 1, 2022 |access-date=December 25, 2018 |work=[[The New York Times]]}}{{cbignore}}</ref><ref name="NYT-20181224b">{{Cite news |last=Widmer |first=Ted |date=December 24, 2018 |title=What Did Plato Think the Earth Looked Like?—For millenniums, humans have tried to imagine the world in space. Fifty years ago, we finally saw it. |url=https://www.nytimes.com/2018/12/24/opinion/plato-earth-christmas-eve-apollo-8.html |url-access=limited |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2018/12/24/opinion/plato-earth-christmas-eve-apollo-8.html |archive-date=January 1, 2022 |access-date=December 25, 2018 |work=[[The New York Times]]}}{{cbignore}}</ref> The three [[astronaut]]s—[[Frank Borman]], [[Jim Lovell]], and [[William Anders]]—were the first humans to see and photograph the [[far side of the Moon]] and an [[Earthrise]].

Apollo 8 launched on December 21, 1968, and was the second [[crewed spaceflight]] mission flown in the United States [[Apollo space program]] (the first, [[Apollo 7|Apollo{{nbsp}}7]], stayed in Earth orbit). Apollo{{nbsp}}8 was the third flight and the first crewed launch of the [[Saturn V]] rocket. It was the first human spaceflight from the [[Kennedy Space Center]], adjacent to [[Cape Canaveral Space Force Station|Cape Kennedy Air Force Station]] in Florida.

Originally planned as the second crewed [[Apollo Lunar Module]] and [[Apollo command and service module|command module]] test, to be flown in an elliptical [[medium Earth orbit]] in early 1969, the mission profile was changed in August 1968 to a more ambitious command-module-only lunar orbital flight to be flown in December, as the lunar module was not yet ready to make its first flight. Astronaut [[Jim McDivitt]]'s crew, who were training to fly the first Lunar Module flight in low Earth orbit, became the crew for the [[Apollo 9|Apollo{{nbsp}}9]] mission, and Borman's crew were moved to the Apollo{{nbsp}}8 mission. This left Borman's crew with two to three months' less training and preparation time than originally planned, and replaced the planned Lunar Module training with translunar navigation training.

Apollo 8 took 68 hours to travel to the Moon. The crew orbited the Moon ten times over the course of twenty hours, during which they made a Christmas Eve [[Apollo TV camera|television broadcast]] where they [[Apollo 8 Genesis reading|read the first ten verses from]] the [[Book of Genesis]]. At the time, the broadcast was the most watched TV program ever. Apollo{{nbsp}}8's successful mission paved the way for [[Apollo 10]] and, with [[Apollo 11|Apollo{{nbsp}}11]] in July 1969, the fulfillment of U.S. president [[John F. Kennedy]]'s goal of landing a man on the Moon before the end of the decade. The Apollo{{nbsp}}8 astronauts returned to Earth on December 27, 1968, when their spacecraft splashed down in the northern Pacific Ocean. The crew members were named [[Time (magazine)|''Time'' magazine]]'s [[Time Person of the Year|"Men of the Year"]] for 1968 upon their return.

==Background==

In the late 1950s and early 1960s, the United States was engaged in the [[Cold War]], a geopolitical rivalry with the [[Soviet Union]].{{sfn|Logsdon|1976|p=134}} On October 4, 1957, the Soviet Union launched [[Sputnik 1]], the first [[Satellite|artificial satellite]]. This unexpected success stoked fears and imaginations around the world. It not only demonstrated that the Soviet Union had the capability to deliver nuclear weapons over intercontinental distances, it challenged American claims of military, economic, and technological superiority.{{sfn|Logsdon|1976|pp=13–15}} The launch precipitated the [[Sputnik crisis]] and triggered the [[Space Race]].{{sfn|Brooks|Grimwood|Swenson|1979|p=1}}

[[President of the United States|President]] [[John F. Kennedy]] believed that not only was it in the national interest of the United States to be superior to other nations, but that the perception of American power was at least as important as the actuality. It was therefore intolerable to him for the Soviet Union to be more advanced in the field of space exploration. He was determined that the United States should compete, and sought a challenge that maximized its chances of winning.{{sfn|Logsdon|1976|p=134}}

The Soviet Union had heavier-lifting [[carrier rocket]]s, which meant Kennedy needed to choose a goal that was beyond the capacity of the existing generation of rocketry, one where the US and Soviet Union would be starting from a position of equality—something spectacular, even if it could not be justified on military, economic, or scientific grounds. After consulting with his experts and advisors, he chose such a project: to land a man on the Moon and return him to the Earth.{{sfn|Logsdon|1976|pp=112–117}} This project already had a name: [[Project Apollo]].{{sfn|Brooks|Grimwood|Swenson|1979|p=15}}

An early and crucial decision was the adoption of [[lunar orbit rendezvous]], under which a specialized spacecraft would land on the lunar surface. The [[Apollo (spacecraft)|Apollo spacecraft]] therefore had three primary components: a [[Apollo command and service module#Command module (CM)|command module]] (CM) with a cabin for the three astronauts, and the only part that would return to Earth; a [[service module]] (SM) to provide the command module with propulsion, electrical power, oxygen, and water; and a two-stage [[lunar module]] (LM), which comprised a descent stage for landing on the Moon and an ascent stage to return the astronauts to lunar orbit.{{sfn|Brooks|Grimwood|Swenson|1979|pp=72–77}} This configuration could be launched by the [[Saturn V]] rocket that was then under development.{{sfn|Brooks|Grimwood|Swenson|1979|pp=48–49}} 

==Framework==
===Prime crew===

{{Spaceflight crew
|terminology = Astronaut
|position1   = Commander
|crew1_up    = [[Frank Borman|Frank F. Borman II]]
|flights1_up = Second and last
|position2   = Command Module Pilot
|crew2_up    = [[Jim Lovell|James A. Lovell Jr.]]
|flights2_up = Third
|position3   = Lunar Module Pilot{{refn | group = n |Lunar Module Pilot was the official title used for the third pilot position in Block II missions, regardless of whether the [[Apollo Lunar Module|LM spacecraft]] was present or not.}}
|crew3_up    = [[William Anders|William A. Anders]]
|flights3_up = Only
|notes       = 
}}

The initial crew assignment of [[Frank Borman]] as Commander, [[Michael Collins (astronaut)|Michael Collins]] as Command Module Pilot (CMP) and [[William Anders]] as Lunar Module Pilot (LMP) for the third crewed Apollo flight was officially announced on November 20, 1967.{{sfn|Brooks|Grimwood|Swenson|1979|p=374}}{{refn | group = n |On a lunar mission, the Command Module Pilot was assigned the role of [[Celestial navigation|navigator]], while the Lunar Module Pilot was assigned the role of [[flight engineer]], responsible for monitoring all spacecraft systems, even if the flight did not include a lunar module. The navigational systems console was in front of the center seat and the environmental and electrical systems console in front of the right hand seat. }} Collins was replaced by [[Jim Lovell]] in July 1968, after suffering a [[intervertebral disc|cervical]] [[Spinal disc herniation|disc herniation]] that required surgery to repair.{{sfn|Collins|2001|pp=288–294}} This crew was unique among pre-[[Space Shuttle]] era missions in that the commander was not the most experienced member of the crew: Lovell had flown twice before, on [[Gemini 7|Gemini VII]] and [[Gemini 12|Gemini XII]]. This would also be the first case of a commander of a previous mission (Lovell, Gemini XII) flying as a non-commander.{{sfn|Hacker|Grimwood|1977|p=533}}{{sfn|Orloff|2000|p=33}} This was also the first mission to reunite crewmates from a previous mission (Lovell and Borman, Gemini VII).

===Backup crew===

{{Spaceflight crew
|terminology = Astronaut
|position1   = Commander
|crew1_up    = [[Neil Armstrong|Neil A. Armstrong]]
|flights1_up = 
|position2   = Command Module Pilot
|crew2_up    = [[Buzz Aldrin|Edwin E. Aldrin Jr.]]
|position3   = Lunar Module Pilot
|crew3_up    = [[Fred Haise|Fred W. Haise Jr.]]
}}

The backup crew assignment of [[Neil Armstrong]] as Commander, Lovell as CMP, and [[Buzz Aldrin]] as LMP for the third crewed Apollo flight was officially announced at the same time as the prime crew.{{sfn|Brooks|Grimwood|Swenson|1979|p=374}} When Lovell was reassigned to the prime crew, Aldrin was moved to CMP, and [[Fred Haise]] was brought in as backup LMP. Armstrong would later command Apollo{{nbsp}}11, with Aldrin as LMP and Collins as CMP. Haise served on the backup crew of Apollo{{nbsp}}11 as LMP and flew on [[Apollo 13|Apollo{{nbsp}}13]] as LMP.{{sfn|Orloff|2000|p=33}}{{sfn|Cunningham|2010|p=109}}

===Support personnel===

During Projects Mercury and Gemini, each mission had a prime and a backup crew. For Apollo, a third crew of astronauts was added, known as the support crew. The support crew maintained the flight plan, checklists, and mission ground rules, and ensured that the prime and backup crews were apprised of any changes. The support crew developed procedures in the simulators, especially those for emergency situations, so that the prime and backup crews could practice and master them in their simulator training.{{sfn|Brooks|Grimwood|Swenson|1979|p=261}} For Apollo{{nbsp}}8, the support crew consisted of [[Ken Mattingly]], [[Vance Brand]], and [[Gerald P. Carr|Gerald Carr]].{{sfn|Orloff|2000|p=33}}{{sfn|Brooks|Grimwood|Swenson|1979|p=375}}

The [[capsule communicator]] (CAPCOM) was an astronaut at the [[Christopher C. Kraft Jr. Mission Control Center|Mission Control Center]] in [[Houston, Texas]], who was the only person who communicated directly with the flight crew.{{sfn|Kranz|2000|p=27}} For Apollo{{nbsp}}8, the CAPCOMs were Michael Collins, Gerald Carr, Ken Mattingly, Neil Armstrong, Buzz Aldrin, Vance Brand, and Fred Haise.{{sfn|Orloff|2000|p=33}}{{sfn|Brooks|Grimwood|Swenson|1979|p=375}}

The mission control teams rotated in three shifts, each led by a flight director. The directors for Apollo{{nbsp}}8 were [[Clifford E. Charlesworth]] (Green team), [[Glynn Lunney]] (Black team), and [[Milton Windler]] (Maroon team).{{sfn|Orloff|2000|p=33}}{{sfn|Phillips|1975|p=179}}{{sfn|Kranz|2000|pp=230, 236, 273, 316, 320}}

===Mission insignia and callsign===

[[File:Apollo 8 Flown Silver Robbins Medallion (SN-264).jpg|thumb|Apollo 8 space-flown silver [[NASA space-flown Robbins medallions of the Apollo missions|Robbins medallion]]]]

The triangular shape of the insignia refers to the shape of the Apollo CM. It shows a red figure{{nbsp}}8 looping around the Earth and Moon to reflect both the mission number and the circumlunar nature of the mission. On the bottom of the{{nbsp}}8 are the names of the three astronauts. The initial design of the insignia was developed by Jim Lovell, who reportedly sketched it while riding in the back seat of a [[Northrop T-38 Talon|T-38]] flight from [[California]] to [[Houston]] shortly after learning of Apollo{{nbsp}}8's re-designation as a lunar-orbital mission.{{sfn|Lattimer|1985|p=53}}

The crew wanted to name their spacecraft, but NASA did not allow it. The crew would have likely chosen ''Columbiad'',{{sfn|Lattimer|1985|p=53}} the name of the giant cannon that launches a space vehicle in [[Jules Verne]]'s 1865 novel ''[[From the Earth to the Moon]]''. The Apollo{{nbsp}}11 CM was named ''Columbia'' in part for that reason.{{sfn|Collins|2001|pp=334–335}}

==Preparations==
===Mission schedule===

{{Main|List of Apollo missions#Alphabetical mission types|l1=List of Apollo missions}}

On September 20, 1967, NASA adopted a seven-step plan for Apollo missions, with the final step being a Moon landing. [[Apollo 4|Apollo{{nbsp}}4]] and [[Apollo 6|Apollo{{nbsp}}6]] were "A" missions, tests of the [[Saturn V|Saturn{{nbsp}}V]] launch vehicle using an uncrewed Block I production model of the command and service module (CSM) in Earth orbit. [[Apollo 5|Apollo{{nbsp}}5]] was a "B" mission, a test of the LM in Earth orbit. Apollo{{nbsp}}7, scheduled for October 1968, would be a "C" mission, a crewed Earth-orbit flight of the CSM. Further missions depended on the readiness of the LM. It had been decided as early as May 1967 that there would be at least four additional missions. Apollo{{nbsp}}8 was planned as the "D" mission, a test of the LM in a low Earth orbit in December 1968 by [[James McDivitt]], [[David Scott]], and [[Rusty Schweickart|Russell Schweickart]], while Borman's crew would fly the "E" mission, a more rigorous LM test in an elliptical medium Earth orbit as Apollo{{nbsp}}9, in early 1969. The "F" Mission would test the CSM and LM in lunar orbit, and the "G" mission would be the finale, the Moon landing.{{sfn|Brooks|Grimwood|Swenson|1979|pp=231–234}}
[[File:Apollo 8 first stage in the Vehicle Assembly Building.jpg|thumb|left|upright|The first stage of AS-503 being erected in the [[Vehicle Assembly Building]] (VAB) on February 1, 1968]]

Production of the LM fell behind schedule, and when Apollo{{nbsp}}8's LM-3 arrived at the [[Kennedy Space Center]] (KSC) in June 1968, more than a hundred significant defects were discovered, leading [[Bob Gilruth]], the director of the [[Manned Spacecraft Center]] (MSC), and others to conclude that there was no prospect of LM-3 being ready to fly in 1968.{{sfn|Brooks|Grimwood|Swenson|1979|p=256}} Indeed, it was possible that delivery would slip to February or March 1969. Following the original seven-step plan would have meant delaying the "D" and subsequent missions, and endangering the program's goal of a lunar landing before the end of 1969.{{sfn|Ertel|Newkirk|Brooks|1978|pp=237–238}} [[George Low]], the Manager of the Apollo Spacecraft Program Office, proposed a solution in August 1968 to keep the program on track despite the LM delay. Since the next CSM (designated as "CSM-103") would be ready three months before LM-3, a CSM-only mission could be flown in December 1968. Instead of repeating the "C" mission flight of Apollo{{nbsp}}7, this CSM could be sent all the way to the Moon, with the possibility of entering a lunar orbit and returning to Earth. The new mission would also allow NASA to test lunar landing procedures that would otherwise have had to wait until [[Apollo 10|Apollo{{nbsp}}10]], the scheduled "F" mission. This also meant that the medium Earth orbit "E" mission could be dispensed with. The net result was that only the "D" mission had to be delayed, and the plan for lunar landing in mid-1969 could remain on timeline.{{sfn|Brooks|Grimwood|Swenson|1979|p=257}}

On August 9, 1968, Low discussed the idea with Gilruth, Flight Director [[Chris Kraft]], and the Director of Flight Crew Operations, [[Donald Slayton]]. They then flew to the [[Marshall Space Flight Center]] (MSFC) in [[Huntsville, Alabama]], where they met with KSC Director [[Kurt Debus]], Apollo Program Director [[Samuel C. Phillips]], [[Rocco Petrone]], and [[Wernher von Braun]]. Jerry Wittenstein, deputy chief of flight mechanics, presented trajectories for the new mission.<ref>family history</ref> Kraft considered the proposal feasible from a flight control standpoint; Debus and Petrone agreed that the next Saturn V, AS-503, could be made ready by December 1; and von Braun was confident the [[pogo oscillation]] problems that had afflicted Apollo{{nbsp}}6 had been fixed. Almost every senior manager at NASA agreed with this new mission, citing confidence in both the hardware and the personnel, along with the potential for a circumlunar flight providing a significant morale boost. The only person who needed some convincing was [[James E. Webb]], the NASA administrator. Backed by the full support of his agency, Webb authorized the mission. Apollo{{nbsp}}8 was officially changed from a "D" mission to a "C-Prime" lunar-orbit mission.{{sfn|Brooks|Grimwood|Swenson|1979|pp=257–260}}

With the change in mission for Apollo 8, Slayton asked McDivitt if he still wanted to fly it. McDivitt turned it down; his crew had spent a great deal of time preparing to test the LM, and that was what he still wanted to do. Slayton then decided to swap the prime and backup crews of the D{{nbsp}}and E{{nbsp}}missions. This swap also meant a swap of spacecraft, requiring Borman's crew to use CSM-103, while McDivitt's crew would use CSM-104, since CM-104 could not be made ready by December. David Scott was not happy about giving up CM-103, the testing of which he had closely supervised, for CM-104, although the two were almost identical, and Anders was less than enthusiastic about being an LMP on a flight with no LM.{{sfn|Brooks|Grimwood|Swenson|1979|p=262}}{{sfn|Collins|2001|pp=296–298}} Instead, Apollo{{nbsp}}8 would carry the<!--LM is pronounced "LEM"--> LM test article, a [[Boilerplate (spaceflight)|boilerplate]] model that would simulate the correct weight and balance of LM-3.{{sfn|Brooks|Grimwood|Swenson|1979|pp=257–260}}

Added pressure on the Apollo program to make its 1969 landing goal was provided by the [[Soviet Union]]'s [[Zond 5|Zond{{nbsp}}5]] mission, which flew some living creatures, including [[Russian tortoise]]s, in a [[cislunar]] loop around the Moon and returned them to Earth on September 21.{{sfn|Chaikin|1994|p=76}} There was speculation within NASA and the press that they might be preparing to launch [[astronaut#Cosmonaut|cosmonauts]] on a similar [[Zond program#Circumlunar missions|circumlunar mission]] before the end of 1968.<ref name="Moon Race 1968">{{Cite magazine |date=December 6, 1968 |title=Poised for the Leap |url=http://www.time.com/time/subscriber/article/0,33009,844661-1,00.html |url-status=dead |archive-url=https://archive.today/20130204221712/http://www.time.com/time/subscriber/article/0,33009,844661-1,00.html |archive-date=February 4, 2013 |access-date=December 15, 2011 |magazine=[[Time (magazine)|Time]]}}</ref>  Compounding these concerns, American reconnaissance satellites observed a mockup [[N1 (rocket)|N1]] being rolled to the pad at Baikonur on November 25, 1967.<ref>{{Cite web |last=Uri |first=John |date=November 17, 2017 |title=50 Years Ago: Soviet's Moon Rocket's Rollout to Pad Affects Apollo Plans |url=https://www.nasa.gov/history/50-years-ago-soviets-moon-rockets-rollout-to-pad-affects-apollo-plans/ |access-date=January 18, 2024 |publisher=NASA}}</ref>
[[File:Mating of Apollo 8 spacecraft with Saturn-V.jpg|thumb|right|Erection and mating of spacecraft 103 to Launch Vehicle AS-503 in the VAB for the Apollo{{nbsp}}8 mission]]
The Apollo 8 crew, now living in the crew quarters at Kennedy Space Center, received a visit from [[Charles Lindbergh]] and his wife, [[Anne Morrow Lindbergh]], the night before the launch.<ref>{{Cite news |last=Benke |first=Richard |date=December 21, 1998 |title=Astronauts look back 30 years after historic lunar launch |url=http://cgi.canoe.ca/SpaceArchive/981221_30.html |url-status=usurped |archive-url=https://archive.today/20121206004702/http://cgi.canoe.ca/SpaceArchive/981221_30.html |archive-date=December 6, 2012 |access-date=June 28, 2013 |work=[[The Augusta Chronicle]] |publisher=[[Morris Communications]] |agency=[[Associated Press]]}}</ref> They talked about how, before his [[Spirit of St. Louis|1927 flight]], Lindbergh had used a piece of string to measure the distance from New York City to Paris on a globe and from that calculated the fuel needed for the flight. The total he had carried was a tenth of the amount that the Saturn V would burn every second. The next day, the Lindberghs watched the launch of Apollo{{nbsp}}8 from a nearby dune.{{sfn|Kluger|2017|pp=149–151}}

===Saturn V redesign===

The Saturn V rocket used by Apollo{{nbsp}}8 was designated AS-503, or the "03rd" model of the Saturn{{nbsp}}V ("5") rocket to be used in the Apollo-Saturn ("AS") program. When it was erected in the [[Vehicle Assembly Building]] on December 20, 1967, it was thought that the rocket would be used for an uncrewed Earth-orbit test flight carrying a [[Boilerplate (spaceflight)|boilerplate]] command and service module. Apollo{{nbsp}}6 had suffered several major problems during its April 1968 flight, including severe [[pogo oscillation]] during its first stage, two second-stage engine failures, and a third stage that failed to reignite in orbit. Without assurances that these problems had been rectified, NASA administrators could not justify risking a crewed mission until additional uncrewed test flights proved the Saturn V was ready.{{sfn|Bilstein|1996|pp=360–370}}

Teams from the MSFC went to work on the problems. Of primary concern was the pogo oscillation, which would not only hamper engine performance, but could exert significant g-forces on a crew. A task force of contractors, NASA agency representatives, and MSFC researchers concluded that the engines vibrated at a frequency similar to the frequency at which the spacecraft itself vibrated, causing a resonance effect that induced oscillations in the rocket. A system that used helium gas to absorb some of these vibrations was installed.{{sfn|Bilstein|1996|pp=360–370}}
[[File:Ap8-KSC-68PC-147.jpg|thumb|upright=1.4|left|Apollo 8 atop Saturn{{nbsp}}V being rolled out to [[Kennedy Space Center Launch Complex 39|Pad 39A]] atop the [[crawler-transporter]]]]

Of equal importance was the failure of three engines during flight. Researchers quickly determined that a leaking hydrogen fuel line ruptured when exposed to vacuum, causing a loss of fuel pressure in engine two. When an automatic shutoff attempted to close the liquid hydrogen valve and shut down engine two, it had accidentally shut down engine three's liquid oxygen due to a miswired connection. As a result, engine three failed within one second of engine two's shutdown. Further investigation revealed the same problem for the third-stage engine—a faulty igniter line. The team modified the igniter lines and fuel conduits, hoping to avoid similar problems on future launches.{{sfn|Bilstein|1996|pp=360–370}}

The teams tested their solutions in August 1968 at the MSFC. A Saturn stage IC was equipped with shock-absorbing devices to demonstrate the team's solution to the problem of pogo oscillation, while a Saturn Stage II was retrofitted with modified fuel lines to demonstrate their resistance to leaks and ruptures in vacuum conditions. Once NASA administrators were convinced that the problems had been solved, they gave their approval for a crewed mission using AS-503.{{sfn|Bilstein|1996|pp=360–370}}

The Apollo 8 spacecraft was placed on top of the rocket on September 21, and the rocket made the slow {{convert|3|mi|adj=on}} journey to the launch pad atop one of NASA's two massive [[crawler-transporter]]s on October{{nbsp}}9.<ref name="satVillust">{{Cite book |last=Akens |first=David S. |url=https://history.nasa.gov/MHR-5/cover.htm |title=Saturn Illustrated Chronology |publisher=[[Marshall Space Flight Center]] |year=1971 |location=Huntsville, AL |chapter=Appendix H—Saturn at the Cape |id=MSFC MHR-5 |access-date=February 1, 2008 |chapter-url=https://history.nasa.gov/MHR-5/app_h.htm |archive-url=https://web.archive.org/web/20080307132427/https://history.nasa.gov/MHR-5/app_h.htm |archive-date=March 7, 2008 |url-status=live}}</ref> Testing continued all through December until the day before launch, including various levels of readiness testing from December{{nbsp}}5 through 11. Final testing of modifications to address the problems of pogo oscillation, ruptured fuel lines, and bad igniter lines took place on December 18, three days before the scheduled launch.{{sfn|Bilstein|1996|pp=360–370}}

==Mission==
===Parameter summary===

[[File:Apollo 8 TLI.jpg|thumb|upright=3.0|Mission profile]]

As the first crewed spacecraft to orbit more than one celestial body, Apollo{{nbsp}}8's profile had two different sets of orbital parameters, separated by a translunar injection maneuver. Apollo lunar missions would begin with a nominal {{convert|100|nmi|km|sigfig=4|adj=on}} circular Earth parking orbit. Apollo{{nbsp}}8 was launched into an initial orbit with an [[apogee]] of {{convert|99.99|nmi|km}} and a [[perigee]] of {{convert|99.57|nmi|km}}, with an [[inclination]] of 32.51° to the [[Equator]], and an [[orbital period]] of 88.19 minutes. Propellant venting increased the apogee by {{convert|6.4|nmi|km}} over the 2{{nbsp}}hours, 44 minutes, and 30 seconds spent in the parking orbit.{{sfn|Orloff|2000|p=45}}

This was followed by a [[trans-lunar injection]] (TLI) burn of the [[S-IVB]] third stage for 318 seconds, accelerating the {{convert|63650|lb|kg|abbr=on}} command and service module and {{convert|19900|lb|kg|abbr=on}} LM test article from an orbital velocity of {{convert|25567|ft/s|m/s}} to the injection velocity of {{convert|35505|ft/s|m/s|abbr=on}}{{sfn|Orloff|2000|p=46}}<ref name="PressKit" /> which set a record for the highest speed, relative to Earth, that humans had ever traveled.{{sfn|Phillips|1975|p=178}} This speed was slightly less than the Earth's [[escape velocity]] of {{convert|36747|ft/s|m/s}}, but put Apollo{{nbsp}}8 into an elongated elliptical Earth orbit, close enough to the Moon to be captured by the Moon's gravity.{{sfn|Woods|2008|pp=108–109}}

The standard lunar orbit for Apollo missions was planned as a nominal {{convert|60|nmi|km|adj=on}} circular orbit above the Moon's surface. Initial lunar orbit insertion was an ellipse with a [[perilune]] of {{convert|60.0|nmi|km}} and an [[apolune]] of {{convert|168.5|nmi|km}}, at an inclination of 12° from the lunar equator. This was then circularized at {{convert|60.7|by|59.7|nmi|km}}, with an orbital period of 128.7 minutes.{{sfn|Orloff|2000|p=46}} The effect of lunar [[mass concentration (astronomy)|mass concentrations]] ("mascons") on the orbit was found to be greater than initially predicted; over the course of the ten lunar orbits lasting twenty hours, the orbital distance was perturbed to {{convert|63.6|by|58.6|nmi|km}}.{{sfn|Orloff|2000|p=39}}

Apollo 8 achieved a maximum distance from Earth of {{convert|203752|nmi|smi km|abbr=off|sp=us}}.{{sfn|Orloff|2000|p=39}}

===Launch and trans-lunar injection===

[[File:Apollo 8 liftoff.jpg|thumb|Apollo 8 launch]]

Apollo 8 was launched at 12:51:00&nbsp;[[UTC]] (7:51&nbsp;am&nbsp;[[Eastern Time Zone (North America)|EST]]) on December 21, 1968, using the Saturn V's [[Multistage rocket|three stages]] to achieve Earth orbit.{{sfn|Orloff|2000|p=39}} The [[S-IC]] first stage landed in the [[Atlantic Ocean]] at {{Coord|30|12|N|74|7|W|name=Apollo 8 S-IC impact}}, and the [[S-II]] second stage landed at {{Coord|31|50|N|37|17|W|name=Apollo 8 S-II impact}}.{{sfn|Orloff|2000|p=34}} The [[S-IVB]] third stage injected the craft into Earth orbit and remained attached to perform the TLI burn that would put the spacecraft on a trajectory to the Moon.{{sfn|Orloff|2000|p=35}}

Once the [[space vehicle|vehicle]] reached Earth orbit, both the crew and [[Christopher C. Kraft Jr. Mission Control Center|Houston flight controllers]] spent the next 2{{nbsp}}hours and 38 minutes checking that the spacecraft was in proper working order and ready for TLI.{{sfn|Brooks|Grimwood|Swenson|1979|p=276}} The proper operation of the S-IVB third stage of the rocket was crucial, and in the last uncrewed test, it had failed to reignite for this burn.{{sfn|Brooks|Grimwood|Swenson|1979|pp=250–252}} Collins was the first CAPCOM on duty, and at 2{{nbsp}}hours, 27 minutes and 22 seconds after launch he radioed, "Apollo{{nbsp}}8. You are Go for TLI."{{sfn|Brooks|Grimwood|Swenson|1979|p=276}} This communication meant that Mission Control had given official permission for Apollo{{nbsp}}8 to go to the Moon. The S-IVB engine ignited on time and performed the TLI burn perfectly.{{sfn|Brooks|Grimwood|Swenson|1979|p=276}} Over the next five minutes, the spacecraft's speed increased from {{convert|7600|to|10800|m/s|sp=us}}.{{sfn|Brooks|Grimwood|Swenson|1979|p=276}}

After the S-IVB had placed the mission on course for the Moon, the command and service modules (CSM), the remaining Apollo{{nbsp}}8 spacecraft, separated from it. The crew then rotated the spacecraft to take photographs of the spent stage and then practiced flying in formation with it. As the crew rotated the spacecraft, they had their first views of the Earth as they moved away from it—this marked the first time humans had viewed the whole Earth at once. Borman became worried that the S-IVB was staying too close to the CSM and suggested to Mission Control that the crew perform a separation maneuver. Mission Control first suggested pointing the spacecraft towards Earth and using the small [[Apollo CSM#Reaction control system|reaction control system]] (RCS) thrusters on the [[Apollo command and service module#Service module (SM)|service module]] (SM) to add {{convert|1.1|ft/s|m/s|abbr=on|sp=us}} to their velocity away from the Earth, but Borman did not want to lose sight of the S-IVB. After discussion, the crew and Mission Control decided to burn in the Earth direction to increase speed, but at {{convert|7.7|ft/s|m/s|abbr=on}} instead. The time needed to prepare and perform the additional burn put the crew an hour behind their onboard tasks.{{sfn|Orloff|2000|p=35}}{{sfn|Brooks|Grimwood|Swenson|1979|pp=276–278}}
[[File:As8-16-2583.jpg|thumb|Apollo 8 [[S-IVB]] rocket stage shortly after separation. The LM test article, a circular boilerplate model of the LM, is visible with four triangular legs connecting it to the stage.]]

Five hours after launch, Mission Control sent a command to the S-IVB to vent its remaining fuel, changing its trajectory. The S-IVB, with the test article attached, posed no further hazard to Apollo{{nbsp}}8, passing the orbit of the Moon and going into a {{convert|0.99|by|0.92|AU|Gm|lk=on|adj=on}} solar orbit with an [[inclination]] of 23.47° from the Earth's equatorial plane, and an orbital period of 340.80 days.{{sfn|Orloff|2000|p=35}} It became a [[:Category:Derelict satellites in heliocentric orbit|derelict object]], and will continue to [[heliocentric orbit|orbit the Sun]] for many years, if not retrieved.<ref name="ha20130923">{{Cite web |title=Saturn S-IVB-503N—Satellite Information |url=http://www.heavens-above.com/SatInfo.aspx?satid=3627&lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT |access-date=September 23, 2013 |website=Satellite database |publisher=Heavens-Above}}</ref>

The Apollo 8 crew were the first humans to pass through the [[Van Allen radiation belt]]s, which extend up to {{convert|15000|mi|km}} from Earth. Scientists predicted that passing through the belts quickly at the spacecraft's high speed would cause a radiation dosage of no more than a chest [[X-ray]], or 1{{nbsp}}[[Gray (unit)|milligray]] (mGy; during a year, the average human receives a dose of 2{{nbsp}}to 3{{nbsp}}mGy from [[background radiation]]). To record the actual radiation dosages, each crew member wore a Personal Radiation [[Dosimeter]] that transmitted data to Earth, as well as three passive film dosimeters that showed the cumulative radiation experienced by the crew. By the end of the mission, the crew members experienced an average radiation dose of 1.6 mGy.<ref name="Biomedical">{{Cite book |last=Bailey |first=J. Vernon |url=http://lsda.jsc.nasa.gov/books/apollo/eboard2.htm |title=Biomedical Results of Apollo |publisher=[[Lyndon B. Johnson Space Center]] |year=1975 |chapter=Radiation Protection and Instrumentation |id=[https://history.nasa.gov/SP-368/sp368.htm NASA SP-368] |access-date=January 28, 2008 |chapter-url=http://lsda.jsc.nasa.gov/books/apollo/S2ch3.htm |archive-url=https://web.archive.org/web/20080117135912/http://lsda.jsc.nasa.gov/books/apollo/S2ch3.htm |archive-date=January 17, 2008 |url-status=dead}} Sec. 2, Ch. 3.</ref>

===Lunar trajectory===

Lovell's main job as Command Module Pilot was as [[flight officer|navigator]]. Although Mission Control normally performed all the navigation calculations, it was necessary to have a crew member adept at navigation so that the crew could return to Earth in case communication with Mission Control was lost. Lovell navigated by star sightings using a [[sextant]] built into the spacecraft, measuring the angle between a star and the Earth's (or the Moon's) [[horizon]]. This task was made difficult by a large cloud of debris around the spacecraft, which made it hard to distinguish the stars.<ref name="journal day 1 green">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 1: Green Team |url=http://history.nasa.gov/ap08fj/03day1_green_sep.htm |url-status=dead |archive-url=https://web.archive.org/web/20080114013205/http://history.nasa.gov/ap08fj/03day1_green_sep.htm |archive-date=January 14, 2008 |access-date=January 30, 2008 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref>

By seven hours into the mission, the crew was about 1{{nbsp}}hour and 40 minutes behind flight plan because of the problems in moving away from the S-IVB and Lovell's obscured star sightings. The crew placed the spacecraft into Passive Thermal Control (PTC), also called "barbecue roll", in which the spacecraft rotated about once per hour around its long axis to ensure even heat distribution across the surface of the spacecraft. In direct sunlight, parts of the spacecraft's outer surface could be heated to over {{convert|200|C|F}}, while the parts in shadow would be {{convert|-100|C|F}}. These temperatures could cause the [[atmospheric reentry#Thermal protection systems|heat shield]] to crack and propellant lines to burst. Because it was impossible to get a perfect roll, the spacecraft swept out a [[Conical surface|cone]] as it rotated. The crew had to make minor adjustments every half hour as the cone pattern got larger and larger.<ref name="journal day 1 Maroon">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 1: Maroon Team |url=https://history.nasa.gov/ap08fj/04day1_maroon.htm |url-status=dead |archive-url=https://web.archive.org/web/20080107002315/https://history.nasa.gov/ap08fj/04day1_maroon.htm |archive-date=January 7, 2008 |access-date=February 4, 2008 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref>
[[File:AS08-16-2593 remastered.jpg|thumb|left|The [[first images of Earth from space|first image taken by humans of the whole Earth]], probably photographed by [[William Anders]].<ref name="journal day 1 green" /> (time tag:  003:42:55) South America is visible in the lower half.]]

The first mid-course correction came eleven hours into the flight. The crew had been awake for more than 16 hours. Before launch, NASA had decided at least one crew member should be awake at all times to deal with problems that might arise. Borman started the first sleep shift but found sleeping difficult because of the constant radio chatter and mechanical noises. Testing on the ground had shown that the [[Apollo command and service module#Service propulsion system|service propulsion system]] (SPS) engine had a small chance of exploding when burned for long periods unless its [[combustion chamber]] was "coated" first by burning the engine for a short period. This first correction burn was only 2.4 seconds and added about {{convert|20.4|ft/s|m/s|abbr=on|sp=us}} velocity [[Retrograde and prograde motion|prograde]] (in the direction of travel).{{sfn|Orloff|2000|p=35}} This change was less than the planned {{convert|24.8|ft/s|m/s|abbr=on|sp=us}}, because of a bubble of [[helium]] in the [[nitrogen tetroxide|oxidizer]] lines, which caused unexpectedly low propellant pressure. The crew had to use the small RCS thrusters to make up the shortfall. Two later planned mid-course corrections were canceled because the Apollo{{nbsp}}8 trajectory was found to be perfect.<ref name="journal day 1 Maroon" />

About an hour after starting his sleep shift, Borman obtained permission from [[flight controller|ground control]] to take a [[Secobarbital|Seconal]] [[Barbiturate|sleeping pill]]. The pill had little effect. Borman eventually fell asleep, and then awoke feeling ill. He vomited twice and had a bout of diarrhea; this left the spacecraft full of small globules of vomit and feces, which the crew cleaned up as well as they could. Borman initially did not want everyone to know about his medical problems, but Lovell and Anders wanted to inform Mission Control. The crew decided to use the Data Storage Equipment (DSE), which could tape voice recordings and telemetry and dump them to Mission Control at high speed. After recording a description of Borman's illness they asked Mission Control to check the recording, stating that they "would like an evaluation of the voice comments".<ref name="journal day 2 green">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 2: Green Team |url=https://history.nasa.gov/ap08fj/06day2_green.htm |url-status=dead |archive-url=https://web.archive.org/web/20080311114001/https://history.nasa.gov/ap08fj/06day2_green.htm |archive-date=March 11, 2008 |access-date=January 30, 2008 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref>

The Apollo 8 crew and Mission Control medical personnel held a conference using an unoccupied second-floor control room (there were two identical control rooms in Houston, on the second and third floors, only one of which was used during a mission). The conference participants concluded that there was little to worry about and that Borman's illness was either a [[Gastroenteritis|24-hour flu]], as Borman thought, or a reaction to the sleeping pill.{{sfn|Collins|2001|p=306}} Researchers now believe that he was suffering from [[space adaptation syndrome]], which affects about a third of astronauts during their first day in space as their [[Labyrinth (inner ear)|vestibular system]] adapts to [[weightlessness]].<ref>{{Cite journal |last=Quine |first=Tony |date=April 2007 |title=Addicted to space: An appreciation of Anousheh Ansari, Part II |journal=Spaceflight |publisher=[[British Interplanetary Society]] |volume=49 |issue=4 |page=144 |issn=0038-6340}}</ref> Space adaptation syndrome had not occurred on previous spacecraft ([[Project Mercury|Mercury]] and [[Project Gemini|Gemini]]), because those astronauts could not move freely in the small cabins of those spacecraft. The increased cabin space in the Apollo command module afforded astronauts greater freedom of movement, contributing to symptoms of space sickness for Borman and, later, astronaut [[Rusty Schweickart]] during Apollo{{nbsp}}9.<ref>{{Cite web |last=Kozlovskaya |first=Inessa B |last2=Bloomberg |first2=Jacob J. |last3=Layne |first3=Charles S. |display-authors=2 |year=2004 |title=The Effects of Long-Duration Space Flight on Eye, Head, and Trunk Coordination During Locomotion |url=http://lsda.jsc.nasa.gov/scripts/experiment/exper.aspx?exp_index=747 |access-date=June 28, 2013 |website=Life Sciences Data Archive |publisher=Lyndon B. Johnson Space Center |id=LSDA Exp ID: 9307191}}</ref>
[[File:Ap8-S68-56531.jpg|thumb|right|Still from film of the crew taken while they were in orbit around the Moon. Frank Borman is in the center.]]

The cruise phase was a relatively uneventful part of the flight, except for the crew's checking that the spacecraft was in working order and that they were on course. During this time, NASA scheduled a television broadcast at 31 hours after launch. The Apollo{{nbsp}}8 crew used a {{convert|2|kg|lb|adj=on}} camera that broadcast in [[black-and-white]] only, using a [[Video camera tube|Vidicon]] tube. The camera had two [[lens (optics)|lenses]], a very [[wide-angle lens|wide-angle (160°) lens]], and a [[telephoto lens|telephoto (9°) lens]].{{sfn|Orloff|2000|p=36}}<ref name="journal day 2 Maroon">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 2: Maroon Team |url=http://history.nasa.gov:80/ap08fj/07day2_maroon.htm |url-status=dead |archive-url=https://web.archive.org/web/20080404232523/http://history.nasa.gov/ap08fj/07day2_maroon.htm |archive-date=April 4, 2008 |access-date=February 4, 2008 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref>

During this first broadcast, the crew gave a tour of the spacecraft and attempted to show how the Earth appeared from space. However, difficulties aiming the narrow-angle lens without the aid of a monitor to show what it was looking at made showing the Earth impossible. Additionally, without proper [[Optical filter|filters]], the Earth image became saturated by any bright source. In the end, all the crew could show the people watching back on Earth was a bright blob.{{sfn|Orloff|2000|p=36}} After broadcasting for 17 minutes, the rotation of the spacecraft took the [[high-gain antenna]] out of view of the receiving stations on Earth and they ended the transmission with Lovell wishing his mother a happy birthday.<ref name="journal day 2 Maroon" />

By this time, the crew had completely abandoned the planned sleep shifts. Lovell went to sleep {{frac|32|1|2}} hours into the flight&nbsp;– three-and-a-half hours before he had planned to. A short while later, Anders also went to sleep after taking a sleeping pill.<ref name="journal day 2 Maroon" /> The crew was unable to see the Moon for much of the outward cruise. Two factors made the Moon almost impossible to see from inside the spacecraft: three of the five windows fogging up due to out-gassed oils from the [[silicone]] [[sealant]], and the [[Orientation (geometry)|attitude]] required for passive thermal control. It was not until the crew had gone behind the Moon that they would be able to see it for the first time.{{sfn|Brooks|Grimwood|Swenson|1979|p=277}}

Apollo 8 made a second television broadcast at 55 hours into the flight. This time, the crew rigged up filters meant for the still cameras so they could acquire images of the Earth through the telephoto lens. Although difficult to aim, as they had to maneuver the entire spacecraft, the crew was able to broadcast back to Earth the first television pictures of the Earth. The crew spent the transmission describing the Earth, what was visible, and the colors they could see. The transmission lasted 23 minutes.{{sfn|Orloff|2000|p=36}}

===Lunar sphere of influence===

[[File:Apollo 8 Image of the Moon (AS08-14-2506).jpg|thumb|This photograph of the Moon was taken from Apollo{{nbsp}}8 at a point above 70 degrees east longitude.]]

At about 55 hours and 40 minutes into the flight, and 13 hours before entering lunar orbit, the crew of Apollo{{nbsp}}8 became the first humans to enter the gravitational [[Sphere of influence (astrodynamics)|sphere of influence]] of another celestial body. In other words, the effect of the Moon's [[Newton's law of universal gravitation|gravitational force]] on Apollo{{nbsp}}8 became stronger than that of the Earth. At the time it happened, Apollo{{nbsp}}8 was {{convert|38759|mi|km}} from the Moon and had a speed of {{convert|3990|ft/s|m/s|abbr=on}} relative to the Moon. This historic moment was of little interest to the crew, since they were still calculating their [[trajectory]] with respect to the launch pad at Kennedy Space Center. They would continue to do so until they performed their last mid-course correction, switching to a [[Frame of reference|reference frame]] based on ideal orientation for the second engine burn they would make in lunar orbit.{{sfn|Orloff|2000|p=36}}

The last major event before Lunar Orbit Insertion (LOI) was a second mid-course correction. It was in [[Retrograde and direct motion|retrograde]] (against the direction of travel) and slowed the spacecraft down by {{convert|2.0|ft/s|m/s|abbr=on}}, effectively reducing the closest distance at which the spacecraft would pass the Moon. At exactly 61 hours after launch, about {{convert|24200|mi|km}} from the Moon, the crew burned the RCS for 11 seconds. They would now pass {{convert|71.7|mi|km}} from the [[Geology of the Moon#Lunar landscape|lunar surface]].{{sfn|Orloff|2000|p=46}}

At 64 hours into the flight, the crew began to prepare for Lunar Orbit Insertion{{nbsp}}1 (LOI-1). This maneuver had to be performed perfectly, and due to [[orbital mechanics]] had to be on the far side of the Moon, out of contact with the Earth. After Mission Control was polled for a "[[Launch status check|go/no go]]" decision, the crew was told at 68 hours that they were Go and "riding the best bird we can find".<ref name="journal day 3 LOI">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 3: The Black Team—Approaching the Moon |url=https://history.nasa.gov/ap08fj/11day3_black_approach.htm |url-status=dead |archive-url=https://web.archive.org/web/20080204015340/https://history.nasa.gov/ap08fj/11day3_black_approach.htm |archive-date=February 4, 2008 |access-date=February 7, 2008 |website=Apollo{{nbsp}}8 Flight Journal |publisher=NASA}}</ref> Lovell replied, "We'll see you on the other side", and for the first time in history, humans travelled behind the Moon and out of radio contact with the Earth.<ref name="journal day 3 LOI" /> [[Frances Northcutt|Frances "Poppy" Northcutt]], who was the first woman in NASA's mission control and helped calculate the return to Earth trajectory for this mission, recounts what it was like when Apollo 8 went behind the Moon for the first time in an interview: "That was a very nerve-racking period on the team I was on, and I think it was a very nerve-racking period in general because of this thing with losing signal. You've got this big mystery going on there on the backside of the Moon. You do not know what's happening and there's not a darn thing anybody here can do about it until we hear from them."<ref>{{Cite web |date=November 14, 2018 |title=NASA Johnson Space Center Oral History Project – Edited Oral History Transcript |url=https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/oral_histories/NorthcuttFM/NorthcuttFM_11-14-18.pdf}}</ref>

With ten minutes remaining before LOI-1, the crew began one last check of the spacecraft systems and made sure that every switch was in its correct position. At that time, they finally got their first glimpses of the Moon. They had been flying over the unlit side, and it was Lovell who saw the first shafts of sunlight [[wiktionary:oblique|oblique]]ly illuminating the lunar surface. The LOI burn was only two minutes away, so the crew had little time to appreciate the view.{{sfn|Lovell|Kluger|1994|pp=48–49}}

===Lunar orbit===

The SPS was ignited at 69 hours, 8{{nbsp}}minutes, and 16 seconds after launch and burned for 4{{nbsp}}minutes and 7{{nbsp}}seconds, placing the Apollo{{nbsp}}8 spacecraft in orbit around the Moon. The crew described the burn as being the longest four minutes of their lives. If the burn had not lasted exactly the correct amount of time, the spacecraft could have ended up in a highly [[ellipse|elliptical]] lunar orbit or even been flung off into space. If it had lasted too long, they could have struck the Moon. After making sure the spacecraft was working, they finally had a chance to look at the Moon, which they would orbit for the next 20 hours.<ref name="nssdc orbit">{{Cite web |title=Apollo 8 |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-118A |access-date=June 28, 2013 |website=[[National Space Science Data Center]] |publisher=NASA}}</ref>

On Earth, Mission Control continued to wait. If the crew had not burned the engine, or the burn had not lasted the planned length of time, the crew would have appeared early from behind the Moon. Exactly at the calculated moment the signal was received from the spacecraft, indicating it was in a {{convert|193.3|by|69.5|mi|km|adj=on}} orbit around the Moon.<ref name="nssdc orbit" />

After reporting on the status of the spacecraft, Lovell gave the first description of what the lunar surface looked like:
{{Blockquote|The Moon is essentially grey, no color; looks like [[plaster of Paris]] or sort of a grayish beach sand. We can see quite a bit of detail. The [[Mare Fecunditatis|Sea of Fertility]] doesn't stand out as well here as it does back on Earth. There's not as much contrast between that and the surrounding craters. The craters are all rounded off. There's quite a few of them, some of them are newer. Many of them look like—especially the round ones—look like hit by [[meteorite]]s or projectiles of some sort. [[Langrenus (crater)|Langrenus]] is quite a huge crater; it's got a central cone to it. The walls of the crater are terraced, about six or seven different [[wiktionary:terrace|terraces]] on the way down.<ref name="journal day 4-123">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 4: Lunar Orbits 1, 2 and 3 |url=https://history.nasa.gov/ap08fj/13day4_orbits123.htm |url-status=dead |archive-url=https://web.archive.org/web/20070922045003/https://history.nasa.gov/ap08fj/13day4_orbits123.htm |archive-date=September 22, 2007 |access-date=September 20, 2007 |website=Apollo 8 Flight Journal |publisher=NASA |df=mdy-all}}</ref>}}
[[File:The Lunar Farside - GPN-2000-001127.jpg|thumb|A portion of the [[Far side of the Moon|lunar far side]] as seen from Apollo{{nbsp}}8]]

Lovell continued to describe the terrain they were passing over. One of the crew's major tasks was [[reconnaissance]] of planned future landing sites on the Moon, especially one in [[Mare Tranquillitatis]] that was planned as the Apollo{{nbsp}}11 landing site. The launch time of Apollo{{nbsp}}8 had been chosen to give the best lighting conditions for examining the site. A [[film camera]] had been set up in one of the spacecraft windows to record one frame per second of the Moon below. Bill Anders spent much of the next 20 hours taking as many photographs as possible of targets of interest. By the end of the mission, the crew had taken over eight hundred 70&nbsp;mm still photographs and {{convert|700|ft}} of 16&nbsp;mm movie film.{{sfn|Orloff|2000|p=37}}

Throughout the hour that the spacecraft was in contact with Earth, Borman kept asking how the data for the SPS looked. He wanted to make sure that the engine was working and could be used to return early to the Earth if necessary. He also asked that they receive a "go/no go" decision before they passed behind the Moon on each orbit.<ref name="journal day 4-123" />

As they reappeared for their second pass in front of the Moon, the crew set up equipment to broadcast a view of the lunar surface. Anders described the craters that they were passing over. At the end of this second orbit, they performed an 11-second LOI-2 burn of the SPS to circularize the orbit to {{convert|70.0|by|71.3|mi|km}}.<ref name="nssdc orbit" /><ref name="journal day 4-123" />

Throughout the next two orbits, the crew continued to check the spacecraft and to observe and photograph the Moon. During the third pass, Borman read a small prayer for his church. He had been scheduled to participate in a service at St. Christopher's [[Episcopal Church (United States)|Episcopal Church]] near [[Seabrook, Texas]], but due to the Apollo{{nbsp}}8 flight, he was unable to attend. A fellow parishioner and engineer at Mission Control, Rod Rose, suggested that Borman read the prayer, which could be recorded and then replayed during the service.<ref name="journal day 4-123" />

===''Earthrise'' and Genesis broadcast===
{{Main|Earthrise|Apollo 8 Genesis reading}}
[[File:Earthrise.jpg|thumb|upright=1.3|The ''[[Earthrise]]'' image]]
[[File:As8 genesis1a.ogv|thumb|upright=1.3|Apollo 8's 1968 Christmas Eve [[Apollo 8 Genesis reading|broadcast and reading]] from the [[Book of Genesis]]]]
When the spacecraft came out from behind the Moon for its fourth pass across the front, the crew witnessed an "Earthrise" in person for the first time in human history.<ref name="journal day 4-456" /> NASA's [[Lunar Orbiter 1]] had taken the first picture of an Earthrise from the vicinity of the Moon, on August 23, 1966.<ref>{{Cite web |title=The 'Other' Lunar Orbiter 1 Earthrise Image |url=https://sservi.nasa.gov/articles/the-other-lunar-orbiter-1-earthrise-image/ |access-date=November 28, 2018 |publisher=Solar System Exploration Research Virtual Institute}}</ref> Anders saw the Earth emerging from behind the lunar horizon and called in excitement to the others, taking a black-and-white photograph as he did so. Anders asked Lovell for color film and then took ''[[Earthrise]]'', a now famous color photo, later picked by ''[[Life (magazine)|Life]]'' magazine as one of its hundred photos of the century.<ref name="journal day 4-456">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 4: Lunar Orbits 4, 5 and 6 |url=https://history.nasa.gov/ap08fj/14day4_orbits456.htm |url-status=dead |archive-url=https://web.archive.org/web/20071002204030/https://history.nasa.gov/ap08fj/14day4_orbits456.htm |archive-date=October 2, 2007 |access-date=September 20, 2007 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref><ref>{{Cite magazine |last=Chaikin |first=Andrew |title=Who Took the Legendary Earthrise Photo From Apollo 8? |url=https://www.smithsonianmag.com/science-nature/who-took-legendary-earthrise-photo-apollo-8-180967505/ |access-date=November 28, 2018 |magazine=Smithsonian}}</ref>

Due to the [[tidal locking|synchronous rotation]] of the Moon about the Earth, Earthrise is not generally visible from the lunar surface. This is because, as seen from any one place on the Moon's surface, Earth remains in approximately the same position in the lunar sky, either above or below the horizon. Earthrise is generally visible only while orbiting the Moon, and at selected surface locations near the Moon's [[lunar limb|limb]], where [[libration]] carries the Earth slightly above and below the lunar horizon.<ref>{{Cite web |date=December 16, 2015 |title=NASA Releases New High-Res Earthrise Image |url=https://www.nasa.gov/image-feature/goddard/lro-earthrise-2015 |access-date=November 28, 2018 |publisher=NASA}}</ref>

Anders continued to take photographs while Lovell assumed control of the spacecraft so that Borman could rest. Despite the difficulty resting in the cramped and noisy spacecraft, Borman was able to sleep for two orbits, awakening periodically to ask questions about their status. Borman awoke fully when he started to hear his fellow crew members make mistakes. They were beginning to not understand questions and had to ask for the answers to be repeated. Borman realized that everyone was extremely tired from not having a good night's sleep in over three days. He ordered Anders and Lovell to get some sleep and that the rest of the flight plan regarding observing the Moon be scrubbed. Anders initially protested, saying that he was fine, but Borman would not be swayed. Anders finally agreed under the condition that Borman would set up the camera to continue to take automatic pictures of the Moon. Borman also remembered that there was a second television broadcast planned, and with so many people expected to be watching, he wanted the crew to be alert. For the next two orbits, Anders and Lovell slept while Borman sat at the helm.<ref name="journal day 4-456" />{{sfn|Kluger|2017|pp=240–241}}

[[File:Apollo 8 genesis reading.ogg|left|thumb|[[Apollo 8 Genesis reading]]]]

As they rounded the Moon for the ninth time, the astronauts began the second television transmission. Borman introduced the crew, followed by each man giving his impression of the lunar surface and what it was like to be orbiting the Moon. Borman described it as being "a vast, lonely, forbidding expanse of nothing".{{sfn|De Groot|2006|p=229}} Then, after talking about what they were flying over, Anders said that the crew had a message for all those on Earth. Each man on board [[Apollo 8 Genesis reading|read a section from the Biblical creation story]] from the [[Book of Genesis]]. Borman finished the broadcast by wishing a Merry Christmas to everyone on Earth. His message appeared to sum up the feelings that all three crewmen had from their vantage point in lunar orbit. Borman said, "And from the crew of Apollo{{nbsp}}8, we close with good night, good luck, a Merry Christmas and God bless all of you—all of you on the good Earth."<ref name="moonport">{{Cite book |last=Benson |first=Charles D. |url=http://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |title=Moonport: A History of Apollo Launch Facilities and Operations |last2=Faherty |first2=William Barnaby |publisher=NASA |year=1978 |chapter=Apollo 8—A Christmas Gift |id=NASA SP-4204 |access-date=February 7, 2008 |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch20-9.html |archive-url=https://web.archive.org/web/20080123133438/http://www.hq.nasa.gov/office/pao/History/SP-4204/contents.html |archive-date=January 23, 2008 |url-status=live}} Ch.20-9.</ref>

The only task left for the crew at this point was to perform the [[trans-Earth injection]] (TEI), which was scheduled for {{frac|2|1|2}} hours after the end of the television transmission. The TEI was the most critical burn of the flight, as any failure of the SPS to ignite would strand the crew in lunar orbit, with little hope of escape. As with the previous burn, the crew had to perform the maneuver above the far side of the Moon, out of contact with Earth.{{sfn|Kluger|2017|pp=250–252}} The burn occurred exactly on time. The spacecraft telemetry was reacquired as it re-emerged from behind the Moon at 89 hours, 28 minutes, and 39 seconds, the exact time calculated. When voice contact was regained, Lovell announced, "Please be informed, there is a [[Santa Claus]]", to which Ken Mattingly, the current CAPCOM, replied, "That's affirmative, you are the best ones to know."<ref name="journal day 4 TEI">{{Cite web |last=Woods |first=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |title=Day 4: Final Orbit and Trans-Earth Injection |url=https://history.nasa.gov/ap08fj/16day4_final_orbit_tei.htm |url-status=dead |archive-url=https://web.archive.org/web/20080116172357/https://history.nasa.gov/ap08fj/16day4_final_orbit_tei.htm |archive-date=January 16, 2008 |access-date=February 7, 2008 |website=Apollo 8 Flight Journal |publisher=NASA}}</ref> The spacecraft began its journey back to Earth on December 25, [[Christmas Day]].{{sfn|Orloff|2000|p=39}}

===Unplanned manual realignment===

Later, Lovell used some otherwise idle time to do some navigational sightings, maneuvering the module to view various stars by using the [[Apollo Guidance Computer]] keyboard. He accidentally erased some of the computer's memory, which caused the [[Apollo PGNCS#Inertial measurement unit|inertial measurement unit]] (IMU) to contain data indicating that the module was in the same relative orientation it had been in before lift-off; the IMU then fired the thrusters to "correct" the module's attitude.<ref name="Benke">{{Cite news |last=Benke |first=Richard |date=December 21, 1998 |title=Astronauts look back 30 years after historic lunar launch |url=http://cgi.canoe.ca/SpaceArchive/981221_30.html |url-status=usurped |archive-url=https://archive.today/20121206004702/http://cgi.canoe.ca/SpaceArchive/981221_30.html |archive-date=December 6, 2012 |access-date=June 28, 2013 |work=[[The Augusta Chronicle]] |agency=[[Associated Press]]}}</ref>

Once the crew realized why the computer had changed the module's attitude, they realized that they would have to reenter data to tell the computer the module's actual orientation. It took Lovell ten minutes to figure out the right numbers, using the thrusters to get the stars [[Rigel]] and [[Sirius]] aligned,{{sfn|Kluger|2017|pp=260–261}} and another 15 minutes to enter the corrected data into the computer.{{sfn|Orloff|2000|p=39}} Sixteen months later, during the [[Apollo 13|Apollo{{nbsp}}13]] mission, Lovell would have to perform a similar manual realignment under more critical conditions after the module's IMU had to be turned off to conserve energy.{{sfn|Lovell|Kluger|1994|pp=282–283}}

===Cruise back to Earth and reentry===

[[File:Apollo 8 reentry, December 27, 1968.jpg|thumb|left|Reentry, December 27, 1968, photographed from a [[KC-135 Stratotanker]] at 40,000 feet|alt=White streaks of light, with bright spots on the right side of them, fill the bottom of the frame. A larger yellow-tinted sphere with a streak is in the center of the frame. The background is black space.]]

The cruise back to Earth was mostly a time for the crew to relax and monitor the spacecraft. As long as the trajectory specialists had calculated everything correctly, the spacecraft would reenter Earth's atmosphere two-and-a-half days after TEI and [[splashdown (spacecraft landing)|splash down]] in the Pacific.{{sfn|Orloff|2000|p=39}}

On Christmas afternoon, the crew made their fifth television broadcast.<ref>{{Cite AV media |url=http://www.collectspace.com/resources/reviews/dvd/apollo8_leaving_the_cradle.html |title=Apollo 8: Leaving the Cradle |date=2003 |type=DVD |publisher=Spacecraft Films/[[20th Century Fox Home Entertainment]] |time=Chapter 5, Disk 2}}</ref> This time, they gave a tour of the spacecraft, showing how an astronaut lived in space. When they finished broadcasting, they found a small present from Slayton in the food locker: a real turkey dinner with stuffing, in the same kind of pack given to the troops in Vietnam.{{sfn|Wilford|1973|p=68}}

Another Slayton surprise was a gift of three [[Miniature (alcohol)|miniature bottles]] of [[brandy]], which Borman ordered the crew to leave alone until after they landed. They remained unopened, even years after the flight.{{sfn|Schefter|1999|p=275}} There were also small presents to the crew from their wives. The next day, at about 124 hours into the mission, the sixth and final TV transmission showed the mission's best video images of the Earth, during a four-minute broadcast.<ref>{{Cite AV media |url=http://www.collectspace.com/resources/reviews/dvd/apollo8_leaving_the_cradle.html |title=Apollo 8: Leaving the Cradle |date=2003 |type=DVD |publisher=Spacecraft Films/20th Century Fox Home Entertainment |time=Chapter 6, Disk 2}}</ref> After two uneventful days, the crew prepared for reentry. The computer would control the reentry, and all the crew had to do was put the spacecraft in the correct attitude, with the blunt end forward. In the event of computer failure, Borman was ready to take over.{{sfn|Chaikin|1998|pp=127–128}}

[[File:The crew of Apollo 8 addresses the crew of the USS Yorktown after a successful splashdown and recovery.jpg|thumb|Crew of Apollo 8 addressing the crew of USS ''Yorktown'' after successful splashdown and recovery]]
Separation from the service module prepared the command module for reentry by exposing the heat shield and shedding unneeded mass. The service module would burn up in the atmosphere as planned.{{sfn|Chaikin|1998|pp=127–128}} Six minutes before they hit the top of the atmosphere, the crew saw the Moon rising above the Earth's horizon, just as had been calculated by the trajectory specialists.<ref name="splashdown1">{{cite web |url=https://history.nasa.gov/ap08fj/22day6_maroon_splash.htm |title=Day 6: The Maroon Team—Splashdown |last1=Woods |first1=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |work=Apollo 8 Flight Journal |publisher=NASA |access-date=February 4, 2008 |archive-url=https://web.archive.org/web/20080206092307/https://history.nasa.gov/ap08fj/22day6_maroon_splash.htm |archive-date=February 6, 2008 |url-status=dead }}</ref> As the module hit the thin outer atmosphere, the crew noticed that it was becoming hazy outside as glowing [[Plasma (physics)|plasma]] formed around the spacecraft.{{sfn|Orloff|2000|p=40}} The spacecraft started slowing down, and the deceleration peaked at {{convert|6|g0}}. With the computer controlling the descent by changing the [[aircraft flight dynamics|attitude]] of the spacecraft, Apollo{{nbsp}}8 rose briefly like a skipping stone before descending to the ocean. At {{convert|30000|ft|km}}, the drogue parachute deployed, stabilizing the spacecraft, followed at {{convert|10000|ft|km}} by the three main parachutes. The spacecraft splashdown position was officially reported as {{Coord|8|8|N|165|1|W|name=Apollo 8 estimated splashdown}} in the North Pacific Ocean, southwest of Hawaii at 15:51:42 UTC on December 27, 1968.<ref name="MissionReport" />

[[File:Ap8-S68-56310.jpg|thumb|Command module on the deck of {{USS|Yorktown|CV-10|6}}]]

When the spacecraft hit the water, the parachutes dragged it over and left it upside down, in what was termed Stable{{nbsp}}2 position. As they were buffeted by a {{convert|10|ft|m|adj=on}} swell, Borman vomited, waiting for the three flotation balloons to right the spacecraft.{{sfn|Kluger|2017|p=277}} About six minutes after splashdown, the command module was righted into a normal apex-up (Stable 1) orientation by its inflatable bag uprighting system.{{sfn|Orloff|2000|p=40}} The first [[frogman]] from [[aircraft carrier]] {{USS|Yorktown|CV-10|6}} arrived 43 minutes after splashdown. Forty-five minutes later, the crew was safe on the flight deck of the ''Yorktown''.<ref name="splashdown1" />{{sfn|Orloff|2000|p=40}}

==Legacy==
===Historical importance===

Apollo 8 came at the end of 1968, a year that had seen much upheaval in the United States and most of the world.<ref name="Men of the Year">{{cite magazine|url=http://www.time.com/time/magazine/article/0,9171,900486,00.html |title=Nation: Men of the Year |date=January 3, 1969 |magazine=[[Time (magazine)|Time]] |access-date=February 13, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080108120930/http://www.time.com/time/magazine/article/0%2C9171%2C900486%2C00.html |archive-date=January 8, 2008 }}</ref> Even though the year saw political assassinations, political unrest in the streets of Europe and America, and the [[Prague Spring]], ''[[Time (magazine)|Time]]'' magazine chose the crew of Apollo{{nbsp}}8 as its [[Time Person of the Year|Men of the Year]] for 1968, recognizing them as the people who most influenced events in the preceding year.<ref name="Men of the Year"/> They had been the first people ever to leave the gravitational influence of the Earth and orbit another celestial body.<ref name="Apollo 8 Firsts">{{cite web |title=Apollo 8 Firsts |url=https://www.pbs.org/wgbh/americanexperience/features/moon-apollo-8s-firsts/ |work=American Experience: Race to the Moon |publisher=PBS |access-date=December 15, 2011 |archive-url=https://web.archive.org/web/20120307035422/http://www.pbs.org/wgbh/amex/moon/peopleevents/e_firsts.html |archive-date=March 7, 2012 |location=Boston |date=September 22, 2005 |url-status=live }}</ref> They had survived a mission that even the crew themselves had rated as having only a fifty-fifty chance of fully succeeding. The effect of Apollo{{nbsp}}8 was summed up in a telegram from a stranger, received by Borman after the mission, that stated simply, "Thank you Apollo{{nbsp}}8. You saved 1968."{{sfn|Chaikin|1994|p=134}}

One of the most famous aspects of the flight was the ''[[Earthrise]]'' picture that the crew took as they came around for their fourth orbit of the Moon.{{sfn|Poole|2008|pp=8, 32}} This was the first time that humans had taken such a picture while actually behind the camera, and it has been credited as one of the inspirations of the first [[Earth Day]] in 1970.<ref>{{cite journal | journal=Aerospace Technology Innovation | url=http://ipp.nasa.gov/innovation/Innovation_84/wnewview.html | title=New Views for A New Century | first=Peggy | last=Wilhide | date=July–August 2000 | volume=8 | issue=4 | publisher=NASA Innovative Partnerships Program |access-date=November 8, 2007 |archive-url=https://web.archive.org/web/20120213191758/http://ipp.nasa.gov/innovation/Innovation_84/wnewview.html |archive-date=February 13, 2012 |url-status=dead}}</ref> It was selected as the first of ''Life'' magazine's ''100 Photographs That Changed the World''.{{sfn|Sullivan|2003|pp=204–205}}
[[File:Apollo 8 Crew Arrives in Houston (23936765502).jpg|thumb|left|Apollo 8 astronauts return to Houston after their mission]]

Apollo 11 astronaut Michael Collins said, "Eight's momentous historic significance was foremost";{{sfn|Murray|Cox|1990|p=333}} while space historian Robert K. Poole saw Apollo{{nbsp}}8 as the most historically significant of all the Apollo missions.{{sfn|Poole|2008|pp=8, 32}} The mission was the most widely covered by the media since the first American orbital flight, [[Mercury-Atlas 6]] by [[John Glenn]], in 1962. There were 1,200 journalists covering the mission, with the [[BBC]]'s coverage broadcast in 54 countries in 15 different languages. The Soviet newspaper ''[[Pravda]]'' featured a quote from {{ill|Boris Nikolaevich Petrov (scientist)|lt=Boris Nikolaevich Petrov|be|Барыс Мікалаевіч Пятроў|de|Boris Nikolajewitsch Petrow|ru|Петров, Борис Николаевич (учёный)}}, Chairman of the Soviet [[Interkosmos]] program, who described the flight as an "outstanding achievement of American space sciences and technology".<ref name="Pravda">{{cite news |first=Boris Nikolaevich |last=Petrov |title=O polete Apollona-8 |newspaper=[[Pravda]] |publisher=[[Communist Party of the Soviet Union]] |location=Moscow, USSR |date=December 30, 1968 |language=ru |trans-title=On the flight of Apollo-8}}</ref> It is estimated that a quarter of the people alive at the time saw—either live or delayed—the Christmas Eve transmission during the ninth orbit of the Moon.{{sfn|Chaikin|1994|p=120}} The Apollo{{nbsp}}8 broadcasts won an [[Emmy Award]], the highest honor given by the [[Academy of Television Arts & Sciences]].<ref name="PBS Emmy Award">{{cite web |title=Telecasts from Apollo 8 |url=https://www.pbs.org/wgbh/americanexperience/features/moon-telecasts-apollo-8/ |work=American Experience: Race to the Moon |publisher=PBS |access-date=December 15, 2011 |archive-url=https://web.archive.org/web/20111027132303/http://www.pbs.org/wgbh/amex/moon/peopleevents/e_telecasts.html |archive-date=October 27, 2011 |location=Boston |date=September 22, 2005 |url-status=live }}</ref>

[[Madalyn Murray O'Hair]], an [[Atheism|atheist]], later caused controversy by bringing a lawsuit against NASA over the reading from Genesis. O'Hair wanted the courts to ban American astronauts—who were all government employees—from public prayer in space.{{sfn|Chaikin|1994|p=623}} Though the case was rejected by the [[Supreme Court of the United States]], apparently for lack of jurisdiction in outer space,<ref>{{cite web|url=http://caselaw.lp.findlaw.com/cgi-bin/getcase.pl?court=US&vol=397&invol=531&friend=nytimes|title=O'Hair v. Paine, 397 U.S. 531|year=1970|work=[[FindLaw]]|access-date=February 13, 2008}}</ref> it caused NASA to be skittish about the issue of religion throughout the rest of the Apollo program. Buzz Aldrin, on Apollo{{nbsp}}11, self-communicated [[Presbyterianism|Presbyterian]] [[Eucharist|Communion]] on the surface of the Moon after landing; he refrained from mentioning this publicly for several years and referred to it only obliquely at the time.{{sfn|Chaikin|1994|pp=204, 623}}
[[File:Scott 1371, Apollo 8.jpg|thumb|right|upright|Apollo 8 commemorative stamp]]

In 1969, the [[United States Post Office Department]] issued a postage stamp ([[Scott catalogue]] #1371) commemorating the Apollo{{nbsp}}8 flight around the Moon. The stamp featured a detail of the famous photograph of the Earthrise over the Moon taken by Anders on Christmas Eve, and the words, "In the beginning God{{nbsp}}...", the first words of the book of Genesis.<ref>{{cite web |url=http://www.1847usa.com/ByYear/1969.htm |title=1969 U.S. Postage Stamp Issues |publisher=1847usa |access-date=June 30, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20121220060113/http://www.1847usa.com/ByYear/1969.htm |archive-date=December 20, 2012 }}</ref> In January 1969, just 18 days after the crew's return to Earth, they appeared in the [[Super Bowl III]] pre-game show, reciting the [[Pledge of Allegiance (United States)|Pledge of Allegiance]], before the [[The Star-Spangled Banner|national anthem]] was performed by trumpeter Lloyd Geisler of the [[National Symphony Orchestra|Washington National Symphony Orchestra]].<ref name=PaleyCenter>{{cite web|title=NBC Broadcast of Super Bowl III|publisher=[[Paley Center for Media]]|url=http://www.paleycenter.org/collection/item/?q=super+bowl+iii&p=1&item=T85:0029|access-date=January 3, 2013}}</ref><ref>{{Cite web|title=Superbowl 3 Anthem – with Apollo 8 with Pledge |url=https://www.youtube.com/watch?v=yOZbhmHtOTg| archive-url=https://ghostarchive.org/varchive/youtube/20211108/yOZbhmHtOTg| archive-date=November 8, 2021 | url-status=live|access-date=February 19, 2021|website=YouTube | date=January 25, 2015 }}{{cbignore}}</ref><ref group=n name="nationalanthem">NFL's website erroneously states that [[Anita Bryant]] performed the anthem, but [[NBC]]'s broadcast of game, available from the [[Paley Center for Media]]'s collection, shows that Geisler performed it.</ref>

===Spacecraft location===

In January 1970, the spacecraft was delivered to [[Osaka]], Japan, for display in the U.S. pavilion at [[Expo '70]].<ref>{{cite book |title=Shanghai Expo: An International Forum on the Future of Cities |url=https://books.google.com/books?id=hd75bRY2jvAC&pg=PA33 |year=2012 |publisher=Routledge |isbn=978-0-415-52462-9 |oclc=778424843 |page=33 |editor=Winter, Tim |access-date=February 21, 2014}}</ref><ref>{{cite news |last= Tareen |first=Sophia |date= December 23, 2013 |title=Apollo 8 astronaut marks 1968 Christmastime broadcast to Earth (12 photos) |url=http://www.deseretnews.com/article/765644112/Apollo-8-astronaut-marks-1968-broadcast-to-Earth.html |archive-url=https://web.archive.org/web/20131227032249/http://www.deseretnews.com/article/765644112/Apollo-8-astronaut-marks-1968-broadcast-to-Earth.html |url-status=dead |archive-date=December 27, 2013 |newspaper=Deseret News |agency=Associated Press |access-date=December 9, 2015 }}</ref> It is now displayed at the Chicago [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], along with a collection of personal items from the flight donated by Lovell and the [[space suit]] worn by Frank Borman.<ref>{{cite web|url=http://www.msichicago.org/exhibit/apollo/index.html|title=The Apollo 8 Command Module|publisher=[[Museum of Science and Industry (Chicago)|Museum of Science and Industry]]|access-date=February 4, 2008| archive-url = https://web.archive.org/web/20071009200922/https://www.msichicago.org/exhibit/apollo/index.html| archive-date=October 9, 2007}}</ref><ref>{{cite web|url=https://airandspace.si.edu/explore-and-learn/topics/apollo/apollo-program/spacecraft/location/cm.cfm|title=Location of Apollo Command Modules|publisher=Smithsonian National Air and Space Museum|access-date=August 27, 2019|archive-date=June 1, 2021|archive-url=https://web.archive.org/web/20210601052353/https://airandspace.si.edu/explore-and-learn/topics/apollo/apollo-program/spacecraft/location/cm.cfm|url-status=dead}}</ref> Jim Lovell's Apollo{{nbsp}}8 space suit is on public display in the Visitor Center at NASA's [[Glenn Research Center]].<ref>{{cite web|url=http://ns.cuyahoga.lib.oh.us/researchinfo/specialists/family_fun.htm#NASA |archive-url=https://web.archive.org/web/20070319212436/http://ns.cuyahoga.lib.oh.us/researchinfo/specialists/family_fun.htm |url-status=dead |archive-date=March 19, 2007 |title=NASA Glenn Visitor Center |publisher=[[Cuyahoga County Public Library]] |access-date=June 30, 2013 }}</ref><ref>{{cite press release |last=Keith |first=Sallie A. |title=GRC News Release 04-012: Heroes in Space Honored at NASA |date=February 20, 2004 |publisher=[[Glenn Research Center|NASA Glenn Research Center]] |url=http://www.nasa.gov/centers/glenn/news/pressrel/2004/04-012.html |url-status=dead |archive-url=https://web.archive.org/web/20041208213103/https://www.nasa.gov/centers/glenn/news/pressrel/2004/04-012.html |archive-date=December 8, 2004 |access-date=March 24, 2024}}{{cbignore}}</ref> Bill Anders's space suit is on display at the [[Science Museum (London)|Science Museum]] in London, United Kingdom.{{sfn|Woods|2008|p=203}}

===In popular culture===

Apollo 8's historic mission has been depicted and referred to in several forms, both documentary and fiction. The various television transmissions and [[16 mm film|16 mm]] footage shot by the crew of Apollo{{nbsp}}8 were compiled and released by NASA in the 1969 documentary ''Debrief: Apollo{{nbsp}}8'', hosted by [[Burgess Meredith]].<ref>{{Cite AV media |year=2008 |title=[[When We Left Earth: The NASA Missions]] |medium=DVD |publisher=[[Discovery, Inc.]] |location=Silver Spring, MD |oclc=232161899}} ''Debrief: Apollo 8'' was released as a bonus feature for the [[Discovery Channel]]'s miniseries DVD release.</ref> In addition, Spacecraft Films released, in 2003, a three-disc DVD set containing all of NASA's TV and 16&nbsp;mm film footage related to the mission, including all TV transmissions from space, training and launch footage, and motion pictures taken in flight.<ref>{{cite AV media |year=2003 |title=Apollo 8: Leaving the Cradle |url=http://www.collectspace.com/resources/reviews/dvd/apollo8_leaving_the_cradle.html |medium=DVD |publisher=Spacecraft Films/20th Century Fox Home Entertainment |access-date=June 23, 2010 |archive-url= https://web.archive.org/web/20100703011003/http://www.collectspace.com/resources/reviews/dvd/apollo8_leaving_the_cradle.html |archive-date=July 3, 2010 |url-status=live}}</ref> Other documentaries include "Race to the Moon" (2005) as part of [[American Experience (season 18)|season 18 of ''American Experience'']]<ref>{{cite web |url=https://www.pbs.org/wgbh/amex/moon/ |title=American Experience—Race to the Moon |publisher=PBS |date=October 31, 2005 |access-date=August 18, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160803052046/http://www.pbs.org/wgbh/amex/moon/ |archive-date=August 3, 2016 }}</ref> and ''[[In the Shadow of the Moon (2007 film)|In the Shadow of the Moon]]'' (2007).<ref>{{cite web |url=http://history.sundance.org/films/3669/in_the_shadow_of_the_moon |title=In the Shadow of the Moon |publisher=[[Sundance Institute]] |access-date=June 30, 2013}}</ref>

The 1994 album ''[[The Songs of Distant Earth (album)|The Songs of Distant Earth]]'' by [[Mike Oldfield]] uses the Anders' reading for the cut "In The Beginning".<ref>{{cite web |url=https://www.discogs.com/master/108535-Mike-Oldfield-The-Songs-Of-Distant-Earth |title=Mike Oldfield – The Songs Of Distant Earth |work=Discogs |date=1994 |access-date=August 28, 2024}}</ref>

Parts of the mission are dramatized in the 1998 miniseries ''[[From the Earth to the Moon (miniseries)|From the Earth to the Moon]]'' episode "[[From the Earth to the Moon (miniseries)#Episodes|1968]]".<ref>{{cite episode |title=1968 |series=[[From the Earth to the Moon (miniseries)|From the Earth to the Moon]] |credits=[[Ron Howard]], [[Brian Grazer]], [[Tom Hanks]], and Michael Bostick—Producers |network=[[HBO]] |air-date=April 1998}}</ref> The S-IVB stage of Apollo{{nbsp}}8 was also portrayed as the location of an alien device in the 1970 ''[[UFO (British TV series)|UFO]]'' episode "Conflict".<ref>{{cite episode |title=Conflict |series=[[UFO (British TV series)|UFO]] |network=[[ITV (TV network)|ITV]] |number=1-05 |air-date=October 7, 1970}}</ref> Apollo{{nbsp}}8's lunar orbit insertion was chronicled with actual recordings in the song "The Other Side", on the 2015 album ''[[The Race for Space (album)|The Race for Space]]'', by the band [[Public Service Broadcasting (band)|Public Service Broadcasting]].<ref>{{Cite news|url=https://www.npr.org/2015/02/15/385549238/first-listen-public-service-broadcasting-the-race-for-space|title=Review: Public Service Broadcasting, 'The Race For Space'|last=Katzif|first=Mike|date=February 15, 2015|work=NPR|access-date=June 10, 2018}}</ref>

==== In fiction ====
[[Kristine Kathryn Rusch]]'s 2007 novella "Recovering Apollo 8" is set in an [[Alternate History|alternate timeline]] where the ''Apollo 8'' malfunctioned and overshoot the Moon's orbit. The plot revolves around attempts made between 2007 and 2068 (of that timeline) to recover the lost spacecraft and its crew.<ref>{{cite magazine |last= Rush |first= Kristine Kathryn |author-link=Kristine Kathryn Rusch |date= February 2007 |title= Recovering Apollo 8 |magazine= [[Asimov's Science Fiction]] }}</ref>

==See also==
* [[Apollo 8 (book)|''Apollo 8'' (book)]]
* [[List of missions to the Moon]]

==Notes==

{{Reflist
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==References==

{{NASA}}
{{Reflist}}

==Bibliography==

{{Refbegin|30em}}
* {{cite book |last=Bilstein |first=Roger E. |title=Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles |url=http://catalog.hathitrust.org/Record/003130142 |access-date=June 28, 2013 |series=The NASA History Series |orig-year=First published 1980 |year=1996 |publisher=NASA |location=Washington, D.C. |isbn=0-16-048909-1 |lccn=97149850 |id=NASA SP-4206 }}
* {{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=https://history.nasa.gov/SP-4205/cover.html |access-date=July 20, 2010 |series=NASA History Series |date=1979 |publisher=Scientific and Technical Information Branch, NASA |location=Washington, D.C. |isbn=978-0-486-46756-6 |oclc=4664449 |lccn=79001042 |id=NASA SP-4205 }}
* {{cite book |last=Chaikin |first=Andrew |author-link=Andrew Chaikin |title=A Man on the Moon: The Voyages of the Apollo Astronauts |title-link=A Man on the Moon |year=1994 |publisher=Viking |location=New York |isbn=978-0-670-81446-6 |lccn=93048680 }}
* {{cite book |last=Chaikin |first=Andrew|title = A Man on the Moon |orig-year=First published 1994 |year=1998 |publisher=Penguin Books |location=New York |isbn=978-0-14-027201-7 }}
* {{cite book |last=Collins |first=Michael |author-link=Michael Collins (astronaut) |title=Carrying the Fire: An Astronaut's Journeys |orig-year=1974 |year=2001 |publisher=Cooper Square Press |location=New York |isbn=978-0-8154-1028-7 |lccn=2001017080 |url=https://archive.org/details/carryingfire00mich }}
* {{cite book |last=Cunningham |first=Walter |author-link=Walter Cunningham |year=2010 |isbn=978-1-876963-24-8 |title=The All-American Boys|orig-year=1977 |publisher=ipicturebooks |oclc=713908039 }}
* {{cite book |last=De Groot |first=Gerard J. |title=Dark Side of the Moon: The Magnificent Madness of the American Lunar Quest |year=2006 |publisher=New York University Press |location=New York |isbn=978-0-8147-1995-4 |lccn=2006016116 |url=https://archive.org/details/darksideofmoonma00degr }}
* {{cite web |last1=Ertel |first1=Ivan D. |last2=Newkirk |first2=Roland W. |last3=Brooks |first3=Courtney G. |title=The Apollo Spacecraft—A Chronology. Vol. IV. Part 3 (1969 3rd quarter) |url=https://history.nasa.gov/SP-4009/v4p3e.htm |id=SP-4009 |location=Washington, D.C. |publisher=NASA |access-date=October 24, 2017 |year=1978 }}
* {{cite book |last1 = Hacker |first1 = Barton C. |last2 = Grimwood |first2 = James M. |year = 1977 |title = On the Shoulders of Titans: A History of Project Gemini |id = SP-4203 |publisher = National Aeronautics and Space Administration |location = Washington, D.C. | url = https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780012208_1978012208.pdf | url-status=dead |archive-url=https://web.archive.org/web/20070629085430/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780012208_1978012208.pdf |archive-date=June 29, 2007 |access-date=March 24, 2024 }}
* {{cite book | last=Kluger | first= Jeffrey |author-link = Jeffrey Kluger | title = Apollo 8: The Thrilling Story of the First Mission to the Moon | year = 2017 | publisher = Henry Holt | isbn=9781627798327 }}
* {{cite book |last=Kranz |first=Gene |author-link=Gene Kranz |title=Failure Is Not An Option |year=2000 |publisher=Simon & Schuster |location=New York |isbn=978-0-7432-0079-0 |oclc=829406416 |url=https://archive.org/details/isbn_9780743200790 }}
* {{cite book |last=Lattimer |first=Dick |title=All We Did Was Fly to the Moon |series=History-alive series |year=1985 |publisher=Whispering Eagle Press |location=Alachua, Florida |isbn=978-0-9611228-0-5 |lccn=85222271 |url=https://archive.org/details/isbn_9780961122805 }}
* {{cite book |last=Logsdon |first=John M. |title=The Decision to Go to the Moon: Project Apollo and the National Interest |location=Chicago |publisher=University of Chicago Press |year=1976 |bibcode=1976dtgt.book.....L |oclc=849992795 }}
* {{cite book |last1=Lovell |first1=Jim |author-link1=Jim Lovell |last2=Kluger |first2=Jeffery |author-link2=Jeffrey Kluger |title=Lost Moon: The Perilous Voyage of Apollo 13 |year=1994 |publisher=Houghton Mifflin |title-link=Lost Moon |location=Boston |isbn=0-395-67029-2 |lccn=94028052 }}
* {{cite book |last1=Murray |first1=Charles |author-link1=Charles Murray (political scientist) |last2=Cox |first2=Catherine Bly |title=Apollo: The Race to the Moon |year=1990 |publisher=Simon & Schuster |location=New York |isbn=978-0-671-70625-8 }}
* {{cite book |last=Orloff |first=Richard W. |title=Apollo by the Numbers: A Statistical Reference |url=https://history.nasa.gov/SP-4029/SP-4029.htm |access-date=June 12, 2013 |series=NASA History Series |year=2000 |publisher=NASA History Division, Office of Policy and Plans |location=Washington, D.C. |isbn=978-0-16-050631-4 |lccn=00061677 |id=NASA SP-2000-4029 |oclc=829406439 }}
* {{cite book |last=Phillips |first=Samuel C. |author-link=Samuel C. Phillips |contribution=The Shakedown Cruises |editor-last=Cortright |editor-first=Edgar M |editor-link=Edgar Cortright |title=Apollo Expeditions to the Moon |url=http://www.hq.nasa.gov/pao/History/SP-350/cover.html |archive-url= https://web.archive.org/web/20080219204538/https://history.nasa.gov/SP-350/ch-9-5.html |archive-date=February 19, 2008 |url-status=live |access-date=January 28, 2008 |year=1975 |publisher=NASA |location=Washington, D.C. |oclc=1623434 |id=NASA SP-350 }}
* {{cite book |last=Poole |first=Robert K. |author-link=Robert Poole (historian) |title=Earthrise: How Man First Saw the Earth |year=2008 |url=https://openlibrary.org/works/OL7938363W/Earthrise?edition=key%3A/books/OL16927352M |publisher=[[Yale University Press]] |location=New Haven, Connecticut |isbn=978-0-300-13766-8 |lccn=2008026764 }}
* {{cite book |last=Schefter |first=James |title=The Race: The Uncensored Story of How America Beat Russia to the Moon |year=1999 |publisher=Doubleday |location=New York |isbn=978-0-385-49253-9 |lccn=98054430 |url=https://archive.org/details/raceuncensored00sche }}
* {{cite book |editor-last=Sullivan |editor-first=Robert |title-link=100 Photographs that Changed the World|title=100 Photographs That Changed the World |year=2003 |publisher=Time, Inc. Home Entertainment |location=New York |isbn=1-931933-84-7 |oclc=987934269 }}
* {{cite book |last=Wilford |first=John Noble |author-link=John Noble Wilford |title=We Reach the Moon |year=1973 |publisher=Putnam Publishing Group |isbn=978-0-448-26152-2 }}
* {{cite book |last=Woods |first=W. David |title=How Apollo Flew to the Moon |year=2008 |publisher=Springer |location=Brelin; New York |isbn=978-0-387-71675-6 |lccn=2007932412 |url-access=registration |url=https://archive.org/details/howapolloflewtom0000wood }}
{{Refend}}

{{NASA}}

==External links==
{{Commons}}
* [https://web.archive.org/web/20130531210211/http://astronautix.com/flights/apollo8.htm "Apollo 8"] at Encyclopedia Astronautica
* {{cite journal |last=Jackson |first=Albert A. |date=Winter 2008–2009 |title=The Essence of the Human Spirit: Apollo 8 |journal=Horizons |volume=34 |issue=1 |pages=24–28 |location=Reston, Virginia |publisher=[[American Institute of Aeronautics and Astronautics]] (AIAA) |type=Newsletter, AIAA Houston Section |access-date=July 1, 2013 |url=http://www.aiaahouston.org/Horizons/december2008.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.aiaahouston.org/Horizons/december2008.pdf |archive-date=October 9, 2022 |url-status=live |ref=none}} Article about the 40th anniversary of Apollo{{nbsp}}8

;Multimedia
* [https://archive.org/details/Apollo8GoForTli ''Apollo 8: Go for TLI''] 1969 NASA film at the [[Internet Archive]]
* [https://archive.org/details/debrief_apollo_8 ''Debrief: Apollo 8''] 1969 NASA film at the Internet Archive
* [https://archive.org/details/Apollo07And0816mmOnboardFilm "Apollo 07 and 08 16mm Onboard Film (1968)"] raw footage taken from Apollos 7{{nbsp}}and{{nbsp}}8 at the Internet Archive
* [https://www.youtube.com/watch?v=1HV9EgQlIhE ''Apollo 8 Around the Moon and Back''] 2018 YouTube video

{{Apollo program}}
{{Moon spacecraft}}
{{Orbital launches in 1968}}
{{NASA space program}}
{{Time Persons of the Year}}
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{{DEFAULTSORT:Apollo 08}}
[[Category:Apollo 8| ]]
[[Category:Apollo program missions|Apollo 08]]
[[Category:Crewed missions to the Moon]]
[[Category:Spacecraft launched in 1968]]
[[Category:1968 in the United States]]
[[Category:Spacecraft which reentered in 1968]]
[[Category:December 1968]]
[[Category:Spacecraft launched by Saturn rockets]]
[[Category:Jim Lovell]]
[[Category:William Anders]]
[[Category:Frank Borman]]
[[Category:Successful space missions]]