Apollo 8
Overview
 
Apollo 8, the second manned mission in the American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Apollo space program, was the first human spaceflight
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....

 to leave Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 orbit; the first to be captured by and escape from the gravitational field of another celestial body; and the first crewed voyage to return to Earth from another celestial body—Earth's Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. The three-man crew of mission Commander Frank Borman
Frank Borman
Frank Frederick Borman, II is a retired NASA astronaut and engineer, best remembered as the Commander of Apollo 8, the first mission to fly around the Moon, making him, along with fellow crew mates Jim Lovell and Bill Anders, the first of only 24 humans to do so...

, Command Module Pilot James Lovell
Jim Lovell
James "Jim" Arthur Lovell, Jr., is a former NASA astronaut and a retired captain in the United States Navy, most famous as the commander of the Apollo 13 mission, which suffered a critical failure en route to the Moon but was brought back safely to Earth by the efforts of the crew and mission...

, and Lunar Module Pilot William Anders
William Anders
William Alison Anders is a former United States Air Force officer, NASA astronaut, businessman, and engineer. He is, along with Apollo 8 crewmates Frank Borman and Jim Lovell, one of the first three persons to have left Earth orbit and traveled to the Moon .-Biography:Anders was born to Arthur...

 became the first humans to travel beyond low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

, the first to see Earth as a whole planet, and then the first to directly see the far side of the Moon
Far side of the Moon
The far side of the Moon is the lunar hemisphere that is permanently turned away, and is not visible from the surface of the Earth. The far hemisphere was first photographed by the Soviet Luna 3 probe in 1959, and was first directly observed by human eyes when the Apollo 8 mission orbited the Moon...

.
Encyclopedia
Apollo 8, the second manned mission in the American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Apollo space program, was the first human spaceflight
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....

 to leave Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 orbit; the first to be captured by and escape from the gravitational field of another celestial body; and the first crewed voyage to return to Earth from another celestial body—Earth's Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. The three-man crew of mission Commander Frank Borman
Frank Borman
Frank Frederick Borman, II is a retired NASA astronaut and engineer, best remembered as the Commander of Apollo 8, the first mission to fly around the Moon, making him, along with fellow crew mates Jim Lovell and Bill Anders, the first of only 24 humans to do so...

, Command Module Pilot James Lovell
Jim Lovell
James "Jim" Arthur Lovell, Jr., is a former NASA astronaut and a retired captain in the United States Navy, most famous as the commander of the Apollo 13 mission, which suffered a critical failure en route to the Moon but was brought back safely to Earth by the efforts of the crew and mission...

, and Lunar Module Pilot William Anders
William Anders
William Alison Anders is a former United States Air Force officer, NASA astronaut, businessman, and engineer. He is, along with Apollo 8 crewmates Frank Borman and Jim Lovell, one of the first three persons to have left Earth orbit and traveled to the Moon .-Biography:Anders was born to Arthur...

 became the first humans to travel beyond low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

, the first to see Earth as a whole planet, and then the first to directly see the far side of the Moon
Far side of the Moon
The far side of the Moon is the lunar hemisphere that is permanently turned away, and is not visible from the surface of the Earth. The far hemisphere was first photographed by the Soviet Luna 3 probe in 1959, and was first directly observed by human eyes when the Apollo 8 mission orbited the Moon...

. The 1968 mission, the first manned launch of a Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...

 rocket, was also the first manned launch from the John F. Kennedy Space Center, Florida, located adjacent to Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...

.

Originally planned as a second Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...

/Command Module
Apollo Command/Service Module
The Command/Service Module was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation...

 test in an elliptical medium Earth orbit
Medium Earth Orbit
Medium Earth orbit , sometimes called intermediate circular orbit , is the region of space around the Earth above low Earth orbit and below geostationary 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, because the Lunar Module was not yet ready to make its first flight. This meant Borman's crew was scheduled to fly two to three months sooner than originally planned, leaving them a shorter time for training and preparation, thus placing more demands than usual on their time and discipline.

After launching on December 21, 1968, Apollo 8 took three days to travel to the Moon. It orbited ten times over the course of 20 hours, during which the crew made a Christmas Eve television broadcast
Apollo TV camera
Television cameras used on the Apollo Project's missions varied in design, with image quality improving significantly with each design. A camera was carried in the Apollo Command Module...

 in which they read the first 10 verses from
Apollo 8 Genesis Reading
On December 24, 1968, in what was the most watched television broadcast at the time, the crew of Apollo 8 read in turn from the Book of Genesis as they orbited the moon...

 the Book of Genesis. At the time, the broadcast was the most watched TV program ever. Apollo 8's successful mission paved the way for Apollo 11
Apollo 11
In early 1969, Bill Anders accepted a job with the National Space Council effective in August 1969 and announced his retirement as an astronaut. At that point Ken Mattingly was moved from the support crew into parallel training with Anders as backup Command Module Pilot in case Apollo 11 was...

 to fulfill U.S. President John F. Kennedy
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....

's goal of landing a man on the Moon before the end of the 1960s.

Crew

This crew was unique among pre-shuttle era missions in that the commander was not the most experienced member of the crew. This was also the first case of the rarity of an astronaut who had flown as commander subsequently flying as a non-commander, as Lovell had previously commanded Gemini XII.

Backup crew

On a lunar mission, the Command Module Pilot (CMP) was assigned the role of navigator
Celestial navigation
Celestial navigation, also known as astronavigation, is a position fixing technique that has evolved over several thousand years to help sailors cross oceans without having to rely on estimated calculations, or dead reckoning, to know their position...

, while the Lunar Module Pilot (LMP) was assigned the role of flight engineer
Flight engineer
Flight engineers work in three types of aircraft: fixed-wing , rotary wing , and space flight .As airplanes became even larger requiring more engines and complex systems to operate, the workload on the two pilots became excessive during certain critical parts of the flight regime, notably takeoffs...

, responsible for monitoring all spacecraft systems, even if the flight didn't include a Lunar Module.

Lovell was originally the CMP on the back-up crew, with Michael Collins
Michael Collins (astronaut)
Michael Collins is a former American astronaut and test pilot. Selected as part of the third group of fourteen astronauts in 1963, he flew in space twice. His first spaceflight was Gemini 10, in which he and command pilot John Young performed two rendezvous with different spacecraft and Collins...

 as the prime crew's CMP. However, Collins was replaced in July 1968, after suffering a cervical
Intervertebral disc
Intervertebral discs lie between adjacent vertebrae in the spine. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together.-Structure:...

 disc herniation
Spinal disc herniation
A spinal disc herniation , informally and misleadingly called a "slipped disc", is a medical condition affecting the spine due to trauma, lifting injuries, or idiopathic, in which a tear in the outer, fibrous ring of an intervertebral disc allows the soft, central portion A spinal disc herniation...

 that required surgery to repair.

Aldrin was originally the backup LMP. When Lovell was rotated to the prime crew, no one with experience on CSM 103 (the specific spacecraft used for the mission) was available, so Aldrin was moved to CMP and Fred Haise brought in as backup LMP. Armstrong went on to command Apollo 11
Apollo 11
In early 1969, Bill Anders accepted a job with the National Space Council effective in August 1969 and announced his retirement as an astronaut. At that point Ken Mattingly was moved from the support crew into parallel training with Anders as backup Command Module Pilot in case Apollo 11 was...

, where Aldrin was returned to the LMP position, and Collins was assigned as CMP.

Mission control

The Earth-based mission control teams for Apollo 8 consisted of astronauts assigned to the support crew, as well as non-astronaut flight directors and their staffs. The support crew members were not trained to fly the mission, but were able to stand in for astronauts in meetings and be involved in the minutiae of mission planning, while the prime and backup crews trained. They also served as capcoms during the mission. For Apollo 8, these crew members included astronauts John S. Bull, Vance D. Brand
Vance D. Brand
Vance DeVoe Brand is an engineer and former test pilot and NASA astronaut. He served as command module pilot during the first U.S.-Soviet joint space flight in 1975, and as commander of three space shuttle missions....

, Gerald P. Carr
Gerald P. Carr
Gerald Paul Carr is an engineer, retired United States Marine Corps colonel and former NASA astronaut. He was commander of Skylab 4, the third and final manned visit to the Skylab Orbital Workshop, from November 16, 1973 to February 8, 1974.-Biography:Carr was born in Denver, Colorado on August...

, and Ken Mattingly
Ken Mattingly
Thomas Kenneth "Ken" Mattingly II, is a retired American astronaut and rear admiral in the United States Navy who flew on the Apollo 16, STS-4 and STS-51-C missions. He had been scheduled to fly on Apollo 13, but was held back due to concerns about a potential illness...

. The mission control teams on Earth rotated in three shifts, each led by a flight director. The directors for Apollo 8 included Cliff Charlesworth (Green team), Glynn Lunney
Glynn Lunney
Glynn S. Lunney is a retired NASA engineer. An employee of NASA since its foundation in 1958, Lunney was a flight director during the Gemini and Apollo programs, and was on duty during historic events such as the Apollo 11 lunar ascent and the pivotal hours of the Apollo 13 crisis...

 (Black team), and Milton Windler (Maroon team).

Mission insignia

The triangular shape of the insignia symbolizes the shape of the Apollo command module. It shows a red figure 8 looping around the earth and moon representing the mission number as well as the circumlunar nature of the mission. On the red number 8 are the names of the three astronauts.

The initial design of the insignia was developed by Jim Lovell. Lovell reportedly sketched the initial design while riding in the backseat of a T-38
T-38 Talon
The Northrop T-38 Talon is a twin-engine supersonic jet trainer. It was the world's first supersonic trainer and is also the most produced. The T-38 remains in service as of 2011 in air forces throughout the world....

 flight from California to Houston, shortly after learning of the re-designation of the flight to become a lunar orbit
Lunar orbit
In astronomy, lunar orbit refers to the orbit of an object around the Moon.As used in the space program, this refers not to the orbit of the Moon about the Earth, but to orbits by various manned or unmanned spacecraft around the Moon...

al mission. The graphic design of the insignia was done by Houston Artist and animator, Bill Bradley.

Planning

Apollo 4
Apollo 4
Apollo 4, , was the first unmanned test flight of the Saturn V launch vehicle, which was ultimately used by the Apollo program to send the first men to the Moon...

 and Apollo 6
Apollo 6
Apollo 6, launched on April 4, 1968, was the Apollo program's second and last A type mission—unmanned test flight of its Saturn V launch vehicle. It was intended to demonstrate full lunar injection capability of the Saturn V, and the capability of the Command Module's heat shield to withstand a...

 had been "A" missions, unmanned tests of the Saturn V launch vehicle using an unmanned Block I production model of the Apollo Command and Service Module in Earth Orbit. , scheduled for October 1968, would be a manned Earth Orbit flight of the CSM, completing the objectives for Mission "C".

Further missions depended on the readiness of the Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...

 (LM). Apollo 8 was planned as the "D" mission, to test the LM in a low Earth orbit in December 1968 by James McDivitt
James McDivitt
James Alton McDivitt is a former NASA astronaut and engineer who flew in the Gemini and Apollo programs. He commanded the Gemini 4 flight in which Edward H. White performed the first US space walk, and later the Apollo 9 flight which was the first manned Earth orbital test of the Apollo Lunar...

, David Scott
David Scott
David Randolph Scott is an American engineer, test pilot, retired U.S. Air Force officer, and former NASA astronaut and engineer, who was one of the third group of astronauts selected by NASA in October 1963...

 and Russell Schweickart
Rusty Schweickart
Russell Louis "Rusty" Schweickart aka Schweikart is an American former astronaut, research scientist, US Air Force fighter pilot, business and government executive...

, while Borman's crew would fly the "E" mission, a more rigorous LM test in an elliptical medium Earth orbit
Medium Earth Orbit
Medium Earth orbit , sometimes called intermediate circular orbit , is the region of space around the Earth above low Earth orbit and below geostationary orbit ....

 as Apollo 9, in early 1969.

But production of the LM fell behind schedule, and when Apollo 8's LM arrived at Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...

 in June 1968, significant defects were discovered, leading Grumman, the lead contractor for the LM, to predict that the first mission-ready LM would not be ready until at least February 1969. This would mean delaying the "D" and subsequent missions, endangering the program's goal of a lunar landing before the end of 1969.

George Low
George Low
George Michael Low, born George Wilhelm Low was a NASA administrator and 14th President of Rensselaer Polytechnic Institute. He was born near Vienna, Austria to Artur and Gertrude Burger Low, small business people in Austria...

, the Manager of the Apollo Spacecraft Program Office, proposed a solution in August to keep the program on track despite the LM delay. Since the Command/Service Module
Apollo Command/Service Module
The Command/Service Module was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation...

 (CSM) would be ready three months before the Lunar Module, a CSM-only mission could be flown in December 1968. Instead of just repeating the "C" mission flight of Apollo 7, this CSM could be sent all the way to the Moon, with the possibility of entering a lunar orbit. The new mission would also allow NASA to test lunar landing procedures that would otherwise have to wait until Apollo 10
Apollo 10
Apollo 10 was the fourth manned mission in the American Apollo space program. It was an F type mission—its purpose was to be a "dry run" for the Apollo 11 mission, testing all of the procedures and components of a Moon landing without actually landing on the Moon itself. The mission included the...

, 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.
Almost every senior manager at NASA agreed with this new mission, citing both confidence in the hardware and personnel, and the potential for a significant morale boost provided by a circumlunar flight. The only person who needed some convincing was James E. Webb
James E. Webb
James Edwin Webb was an American government official who served as the second administrator of NASA from February 14, 1961 to October 7, 1968....

, the NASA administrator. With the rest of his agency in support of the new mission, Webb eventually approved the mission change. The mission was officially changed from a "D" mission to a "C-Prime" Lunar Orbit mission, but was still referred to in press releases as an Earth Orbit mission at Webb's direction. No public announcement was made about the change in mission until November 12, three weeks after Apollo 7's successful Earth Orbit mission and less than 40 days before launch.

With the change in mission for Apollo 8, Director of Flight Crew Operations Deke Slayton
Deke Slayton
Donald Kent Slayton , better known as Deke Slayton, was an American World War II pilot and later, one of the original NASA Mercury Seven astronauts....

 decided to swap the crews of the D and E missions. McDivitt, the commander of the D mission, has said he was never offered the circumlunar flight, but would probably have turned it down, as he wanted to fly the Lunar Module. Borman, on the other hand, jumped at the chance: his original mission would have largely been a repeat of the previous flight, albeit in a higher orbit. This swap also meant a swap of spacecraft, requiring Borman's crew to use CSM-103, while McDivitt's crew would use CSM-104.

On September 9, the crew entered the simulators to begin their preparation for the flight. By the time the mission flew, the crew had spent seven hours training for every actual hour of flight. Although all crew members were trained in all aspects of the mission, it was necessary to specialize. Borman, as commander, was given training on controlling the spacecraft during the re-entry
Atmospheric reentry
Atmospheric entry is the movement of human-made or natural objects as they enter the atmosphere of a celestial body from outer space—in the case of Earth from an altitude above the Kármán Line,...

. Lovell was trained on navigating
Celestial navigation
Celestial navigation, also known as astronavigation, is a position fixing technique that has evolved over several thousand years to help sailors cross oceans without having to rely on estimated calculations, or dead reckoning, to know their position...

 the spacecraft in case communication was lost with the Earth. Anders was placed in charge of checking that the spacecraft was in working order.

Added pressure on the Apollo program to make its 1969 landing goal was provided by the Soviet Union's
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 flight of some living creatures, including Russian tortoise
Russian Tortoise
The Russian tortoise, Horsfield's tortoise or Central Asian tortoise is a species of tortoise that is a popular pet...

s, in a cislunar loop around the Moon on Zond 5
Zond 5
Zond 5, a formal member of the Soviet Zond program and unmanned version of Soyuz 7K-L1 manned moon-flyby spacecraft, was launched from a Tyazheliy Sputnik in Earth parking orbit to make scientific studies during a lunar flyby and to return to Earth....

 and return to Earth on September 21. There was speculation that they might be preparing to launch men on a similar circumlunar mission before the end of 1968.

The Apollo 8 crew, now living in the crew quarters at Kennedy Space Center, received a visit from Charles Lindbergh
Charles Lindbergh
Charles Augustus Lindbergh was an American aviator, author, inventor, explorer, and social activist.Lindbergh, a 25-year-old U.S...

 and his wife, Anne Morrow Lindbergh
Anne Morrow Lindbergh
Anne Morrow Lindbergh was an American author, aviator, and the spouse of fellow aviator Charles Lindbergh.She was an acclaimed author whose books and articles spanned the genres of poetry to non-fiction, touching upon topics as diverse as youth and age; love and marriage; peace, solitude and...

, the night before the launch. They talked about how, before his 1927 flight
Spirit of St. Louis
The Spirit of St. Louis is the custom-built, single engine, single-seat monoplane that was flown solo by Charles Lindbergh on May 20–21, 1927, on the first non-stop flight from New York to Paris for which Lindbergh won the $25,000 Orteig Prize.Lindbergh took off in the Spirit from Roosevelt...

, 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 was a tenth of the amount that the Saturn V would burn every second. The next day, the Lindberghs watched the launch of Apollo 8 from a nearby dune. Anne Morrow Lindbergh would later write a book about the Apollo program, entitled Earth Shine, which mentions this mission.

Saturn V

The Saturn V rocket used by Apollo 8 was designated SA-503, or the "03rd" model of the Saturn V ("5") Rocket to be used in the Saturn-Apollo ("SA") program. When it was erected in the Vertical Assembly Building
Vehicle Assembly Building
The Vehicle Assembly Building, or VAB, at NASA's Kennedy Space Center was used to assemble and house American manned launch vehicles from 1968-2011. It is the fourth largest building in the world by volume...

 on December 20, 1967, it was thought that the rocket would be used for an unmanned Earth-orbit test flight carrying a boilerplate Command/Service Module. Apollo 6 had suffered several major problems during its April 1968 flight, including severe pogo oscillation
Pogo oscillation
Pogo oscillation is a potentially dangerous type of self-excited combustion oscillation in liquid fuel rocket engines. This oscillation results in variations of thrust from the engines, causing variations of acceleration on the rocket's structure, giving variations in fuel pressure and flow rate....

 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 manned mission until additional unmanned test flights proved that the Saturn V was ready.

Teams from the Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...

 (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 using helium gas to absorb some of these vibrations was installed.

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 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.

The teams tested their solutions in August 1968 at the Marshall Space Flight Center. 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 were solved, they gave their approval for a manned mission using SA-503.

The Apollo 8 spacecraft was placed on top of the rocket on September 21 and the rocket made the slow 3-mile (5 km) journey to the launch pad on October 9. Testing continued all through December until the day before launch, including various levels of readiness testing from December 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, a mere three days before the scheduled launch.

Parameter summary

As the first manned spacecraft to orbit more than one celestial body, Apollo 8's profile had two different sets of orbital parameters, separated by a translunar injection maneuver.

Apollo lunar missions would begin with a nominal 100 nautical miles (185.2 km) circular Earth parking orbit. Apollo 8 was launched into an initial orbit with an apogee of 99.99 nautical miles (185.2 km) and a perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...

 of 99.57 nautical miles (184.4 km), with an inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...

 of 32.51° to the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

, and an orbital period
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...

 of 88.19 minutes. Propellant venting increased the apogee by 6.4 nautical miles (11.9 km) over the 2 hours, 44 minutes and 30 seconds spent in the parking orbit.

This was followed by a Trans-Lunar Injection (TLI) burn of the S-IVB
S-IVB
The S-IVB was built by the Douglas Aircraft Company and served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine...

 third stage for 318 seconds, accelerating the 63531 lb (28,817.2 kg) spacecraft from an orbital velocity of 25567 feet per second (7,792.8 m/s) to the injection velocity of 35505 ft/s (10,821.9 m/s), which set a record for the highest speed, relative to Earth, that humans had ever traveled. This speed was slightly less than the Earth's escape velocity
Escape velocity
In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero gravitational potential energy is negative since gravity is an attractive force and the potential is defined to be zero at infinity...

 of 36747 feet per second (11,200.5 m/s), but put Apollo 8 into an elongated elliptical Earth orbit, to a point where the Moon's gravity would capture it.

The standard lunar orbit for Apollo missions was planned as a nominal 60 nautical miles (111.1 km) circular orbit above the Moon's surface. Initial lunar orbit insertion was an ellipse with a perilune of 60 nautical miles (111.1 km) and an apolune of 168.5 nautical miles (312.1 km), at an inclination of 12° from the lunar equator. This was then circularized at 60.7 nautical miles (112.4 km) by 59.7 nautical miles (110.6 km), with an orbital period of 128.7 minutes. The effect of lunar mass concentrations ("masscons") on the orbit was found to be greater than initially predicted; over the course of the twenty-hour mission, the orbit was perturbated to 63.6 nautical miles (117.8 km) by 58.6 nautical miles (108.5 km).

Apollo 8 achieved a maximum distance from Earth of 203752 nautical miles (377,348.7 km).

Launch and trans-lunar injection

Apollo 8 launched at 7:51:00 a.m. Eastern Standard Time on December 21, 1968, using the Saturn V's three stages
Multistage rocket
A multistage rocket is a rocket that usestwo or more stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or...

, S-IC
S-IC
The S-IC was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer...

, S-II
S-II
The S-II was the second stage of the Saturn V rocket. It was built by North American Aviation. Using liquid hydrogen and liquid oxygen it had five J-2 engines in a cross pattern...

, and S-IVB
S-IVB
The S-IVB was built by the Douglas Aircraft Company and served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine...

, to achieve Earth orbit. The launch phase experienced only three minor problems: The engines of the first stage, S-IC, underperformed by 0.75%, causing the engines to burn for 2.45 seconds longer than planned, and toward the end of the second stage burn, S-II, the rocket underwent pogo oscillation
Pogo oscillation
Pogo oscillation is a potentially dangerous type of self-excited combustion oscillation in liquid fuel rocket engines. This oscillation results in variations of thrust from the engines, causing variations of acceleration on the rocket's structure, giving variations in fuel pressure and flow rate....

s. Frank Borman estimated the oscillations were approximately and (±2.5 m/s2).

All three rocket stages fired during launch; the S-IC and S-II detached during launch. The S-IC impacted the Atlantic Ocean at 30°12′N 74°7′W and the S-II second stage at 31°50′N 37°17′W. The third stage of the rocket, S-IVB, assisted in driving the craft into Earth orbit but remained attached to later perform the TLI burn that would put the spacecraft on a trajectory to the Moon.

Once in Earth orbit, both the Apollo 8 crew and Mission Control spent the next 2 hours and 38 minutes checking that the spacecraft was in proper working order and ready for TLI. The proper operation of third stage of the rocket, S-IVB was crucial; In the last unmanned test, the S-IVB had failed to re-ignite for TLI.

During the flight, three fellow astronauts served on the ground as capsule communicators (usually referred to as "CAPCOMs") on a rotating schedule. The CAPCOMs were the only people who regularly communicated with the crew. Michael Collins was the first CAPCOM on duty and at 2 hours, 27 minutes and 22 seconds after launch radioed, "Apollo 8. You are Go for TLI". This communication signified that Mission Control had given official permission for Apollo 8 to go to the moon. Over the next 12 minutes before the TLI burn, the Apollo 8 crew continued to monitor the spacecraft and the S-IVB. The engine ignited on time and performed the TLI burn perfectly.

After the S-IVB had performed its required tasks, it was jettisoned. The crew then rotated the spacecraft to take some 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 could view the whole Earth at once. Borman became worried that the S-IVB was staying too close to the Command/Service Module and suggested to Mission Control that the crew perform a separation maneuver. Mission Control first suggested pointing the spacecraft towards Earth and using the Reaction Control System (RCS) thrusters on the Service Module to add 3 ft/s (0.9144 m/s) 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 this direction, but at 9 ft/s (2.7 m/s) instead. These discussions put the crew an hour behind their flight plan.

Five hours after launch, Mission Control sent a command to the S-IVB booster to vent its remaining fuel through its engine bell to change the booster's trajectory. This S-IVB would then pass the Moon and enter into a solar orbit, posing no further hazard to Apollo 8. The S-IVB subsequently went into a 0.99 by solar orbit with an inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...

 of 23.47° from the plane of the ecliptic
Plane of the ecliptic
The plane of the ecliptic is the plane of the Earth's orbit around the Sun. It is the primary reference plane when describing the position of bodies in the Solar System, with celestial latitude being measured relative to the ecliptic plane. In the course of a year, the Sun's apparent path through...

, and an orbital period of 340.80 days.

The Apollo 8 crew were the first humans to pass through the Van Allen radiation belt
Van Allen radiation belt
The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...

s, which extend up to 15000 miles (24,140.1 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
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

, or 1 milligray
Gray (unit)
The gray is the SI unit of absorbed radiation dose of ionizing radiation , and is defined as the absorption of one joule of ionizing radiation by one kilogram of matter ....

 (during the course of a year, the average human receives a dose of 2 to 3 mGy). To record the actual radiation dosages, each crew member wore a Personal Radiation Dosimeter
Dosimeter
Dosimeters measure an individual's or an object'sexposure to something in the environment — particularly to a hazard inflicting cumulative impact over long periods of time, or over a lifetime...

 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 experienced an average radiation dose of 1.6 mGy.

Lunar trajectory

Jim Lovell's main job as Command Module Pilot was as navigator
Flight officer
The title flight officer was a military rank used by the United States Armed Forces where it was an air force warrant officer rank. It was also an air force rank in several Commonwealth nations where it was used for female officers and was equivalent to the rank of flight lieutenant...

. Although Mission Control performed all of the actual navigation calculation, it was necessary to have a crew member serving as navigator so that the crew could successfully return to Earth in case of communication loss with Mission Control. Lovell navigated by star sightings using a sextant
Sextant
A sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight...

 built into the spacecraft, measuring the angle between a star and the Earth's (or the Moon's) horizon
Horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...

. This task proved to be difficult, as a large cloud of debris around the spacecraft formed by the venting S-IVB made it hard to distinguish the stars.

By seven hours into the mission, the crew was about one hour and 40 minutes behind flight plan due to the issues of moving away from the S-IVB and Lovell's obscured star sightings. The crew now placed the spacecraft into Passive Thermal Control (PTC), also known as "barbecue" roll. PTC involved the spacecraft rotating about once per hour along its long axis to ensure even heat distribution across the surface of the spacecraft. In direct sunlight, the spacecraft could be heated to over 200 °C (392 °F) while the parts in shadow would be -100 C. These temperatures could cause the heat shield to crack or propellant lines to burst. As it was impossible to get a perfect roll, the spacecraft actually swept out a cone
Conical surface
In geometry, a conical surface is the unbounded surface formed by the union of all the straight lines that pass through a fixed point — the apex or vertex — and any point of some fixed space curve — the directrix — that does not contain the apex...

 as it rotated. The crew had to make minor adjustments every half hour as the cone pattern got larger and larger.

The first mid-course correction came 11 hours into the flight. Testing on the ground had shown that the Service Propulsion System (SPS) engine had a small chance of exploding when burned for long periods unless its combustion chamber
Combustion chamber
A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...

 was "coated" first. Burning the engine for a short period would accomplish coating. This first correction burn was only 2.4 seconds and added about 20.4 ft/s (6.2 m/s) velocity prograde
Retrograde and direct motion
Apparent retrograde motion is the motion of a planetary body in a direction opposite to that of other bodies within its system as observed from a particular vantage point...

 (in the direction of travel). This change was less than the planned 24.8 ft/s (7.6 m/s) due to a bubble of helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

 in the oxidizer
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 lines causing lower than expected fuel pressure. The crew had to use the small Reaction Control System (RCS) thrusters to make up the shortfall. Two later planned mid-course corrections were canceled as the Apollo 8 trajectory was found to be perfect.

11 hours into the flight, the crew had been awake for over 16 hours. Before launch, NASA had decided that at least one crew member should be awake at all times to deal with any issues that might arise. Borman started the first sleep shift, but between the constant radio chatter and mechanical noises, he found sleep difficult.
About an hour after starting his sleep shift, Borman requested clearance to take a Seconal
Secobarbital
Secobarbital sodium is a barbiturate derivative drug that was first synthesized in 1928 in Germany. It possesses anaesthetic, anticonvulsant, sedative and hypnotic properties...

 sleeping pill
Barbiturate
Barbiturates are drugs that act as central nervous system depressants, and can therefore produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, as hypnotics, and as anticonvulsants...

. However, the pill had little effect. Borman eventually fell asleep but then awoke feeling ill. He vomited twice and had a bout of diarrhea that left the spacecraft full of small globules of vomit and feces that the crew cleaned up to the best of their ability. Borman initially decided that he 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 requested that Mission Control check the recording, stating that they "would like an evaluation of the voice comments".

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 floor, only one of which was used during a mission). The conference participants decided that there was little to worry about and that Borman's illness was either a 24-hour flu
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

, as Borman thought, or a reaction to the sleeping pill. Researchers now believe that he was suffering from space adaptation syndrome
Space adaptation syndrome
Space adaptation syndrome or space sickness is a condition experienced by around half of space travelers during adaptation to weightlessness. It is related to motion sickness, as the vestibular system adapts to weightlessness.- Cause and remedy :...

, which affects about a third of astronauts during their first day in space as their vestibular system adapts to weightlessness
Weightlessness
Weightlessness is the condition that exists for an object or person when they experience little or no acceleration except the acceleration that defines their inertial trajectory, or the trajectory of pure free-fall...

. Space adaptation syndrome had not been an issue on previous spacecraft (Mercury
Project Mercury
In January 1960 NASA awarded Western Electric Company a contract for the Mercury tracking network. The value of the contract was over $33 million. Also in January, McDonnell delivered the first production-type Mercury spacecraft, less than a year after award of the formal contract. On February 12,...

 and Gemini
Project Gemini
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....

), as those astronauts were unable to move freely in the comparatively smaller cabins of those spacecraft. The increased cabin space in the Apollo Command Module afforded astronauts greater freedom of movement, contributing to symptoms of spacesickness for Borman and, later, astronaut Russell Schweickart during Apollo 9
Apollo 9
Apollo 9, the third manned mission in the American Apollo space program, was the first flight of the Command/Service Module with the Lunar Module...

.

The cruise phase was a relatively uneventful part of the flight, except for the crew 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 8 crew used a 2 kg camera that broadcast in black-and-white
Black-and-white
Black-and-white, often abbreviated B/W or B&W, is a term referring to a number of monochrome forms in visual arts.Black-and-white as a description is also something of a misnomer, for in addition to black and white, most of these media included varying shades of gray...

 only, using a Vidicon
Video camera tube
In older video cameras, before the mid to late 1980s, a video camera tube or pickup tube was used instead of a charge-coupled device for converting an optical image into an electrical signal. Several types were in use from the 1930s to the 1980s...

 tube. The camera had two lenses
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...

, a very wide-angle (160°) lens
Wide-angle lens
From a design perspective, a wide angle lens is one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length; this enables either large tilt & shift movements with a view camera, or lenses with wide fields of view.More informally,...

, and a telephoto (9°) lens
Telephoto lens
In photography and cinematography, a telephoto lens is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus...

.

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, the Earth image became saturated by any bright source without proper filters
Filter (optics)
Optical filters are devices which selectively transmit light of different wavelengths, usually implemented as plane glass or plastic devices in the optical path which are either dyed in the mass or have interference coatings....

. In the end, all the crew could show the people watching back on Earth was a bright blob. After broadcasting for 17 minutes, the rotation of the spacecraft took the high-gain antenna
High-gain antenna
A high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...

 out of view of the receiving stations on Earth and they ended the transmission with Lovell wishing his mother a happy birthday.

By this time, the crew had completely abandoned the planned sleep shifts. Lovell went to sleep 32½ hours into the flight—3½ hours before he had planned to. A short while later, Anders also went to sleep after taking a sleeping pill.

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
Silicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....

 sealant
Sealant
A sealant may be viscous material that has little or no flow characteristics and stay where they are applied or thin and runny so as to allow it to penetrate the substrate by means of capillary reaction...

, and the attitude required for the PTC. It was not until the crew had gone behind the Moon that they would be able to see it for the first time.

The Apollo 8 made a second television broadcast at 55 hours into the flight. This time, the crew rigged up filters
Filter (optics)
Optical filters are devices which selectively transmit light of different wavelengths, usually implemented as plane glass or plastic devices in the optical path which are either dyed in the mass or have interference coatings....

 meant for the still cameras so they could acquire images of the Earth through the telephoto lens
Telephoto lens
In photography and cinematography, a telephoto lens is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus...

. 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 and what was visible and the colors they could see. The transmission lasted 23 minutes.

Lunar sphere of influence

At about 55 hours and 40 minutes into the flight, the crew of Apollo 8 became the first humans to enter the gravitational sphere of influence of another celestial body. In other words, the effect of the Moon's gravitational force
Newton's law of universal gravitation
Newton's law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them...

 on Apollo 8 became stronger than that of the Earth. At the time it happened, Apollo 8 was 38759 miles (62,376.4 km) from the Moon and had a speed of 3990 ft/s (1,216.2 m/s) relative to the Moon. This historic moment was of little interest to the crew since they were still calculating their trajectory
Trajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...

 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 reference frame
Frame of reference
A frame of reference in physics, may refer to a coordinate system or set of axes within which to measure the position, orientation, and other properties of objects in it, or it may refer to an observational reference frame tied to the state of motion of an observer.It may also refer to both an...

 based on ideal orientation for the second engine burn they would make in lunar orbit. It was only 13 hours until they would be in lunar orbit.

The last major event before Lunar Orbit Insertion was a second mid-course correction. It was in retrograde
Retrograde and direct motion
Apparent retrograde motion is the motion of a planetary body in a direction opposite to that of other bodies within its system as observed from a particular vantage point...

 (against direction of travel) and slowed the spacecraft down by 2 ft/s (0.6096 m/s), effectively lowering the closest distance that the spacecraft would pass the moon. At exactly 61 hours after launch, about 24200 miles (38,946 km) from the Moon, the crew burned the RCS for 11 seconds. They would now pass 71.7 miles (115.4 km) from the lunar surface.

At 64 hours into the flight, the crew began to prepare for Lunar Orbit Insertion-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 Go/No Go decision, the crew was told at 68 hours, they were Go and "riding the best bird we can find". At 68 hours and 58 minutes, the spacecraft went behind the Moon and out of radio contact with the Earth.

With 10 minutes before the LOI-1, the crew began one last check of the spacecraft systems and made sure that every switch was in the correct place. 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 obliquely illuminating the lunar surface. The LOI burn was only two minutes away, so the crew had little time to appreciate the view.

Lunar orbit

The SPS ignited at 69 hours, 8 minutes, and 16 seconds after launch and burned for 4 minutes and 13 seconds, placing the Apollo 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 elliptical
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...

 lunar orbit or even flung off into space. If it lasted too long they could have impacted 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.

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 appear early from behind the Moon. However, this time came and went without Apollo 8 reappearing. Exactly at the calculated moment, the signal was received from the spacecraft, indicating it was in a 193.3 by orbit about the Moon.

After reporting on the status of the spacecraft, Lovell gave the first description of what the lunar surface looked like:
Lovell continued to describe the terrain they were passing over. One of the crew's major tasks was reconnaissance
Reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

 of planned future landing sites on the Moon, especially one in Mare Tranquillitatis
Mare Tranquillitatis
Mare Tranquillitatis is a lunar mare that sits within the Tranquillitatis basin on the Moon. The mare material within the basin consists of basalt formed in the intermediate to young age group of the Upper Imbrian epoch. The surrounding mountains are thought to be of the Lower Imbrian epoch, but...

 that would be the Apollo 11 landing site. The launch time of Apollo 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 a frame every 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 700 photographs of the Moon and 150 of the Earth.

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.

As they reappeared for their second pass in front of the Moon, the crew set up the 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 the 11-second LOI-2 burn of the SPS to circularize the orbit to 70 by.

Through the next two orbits, the crew continued to keep check of 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
Episcopal Church (United States)
The Episcopal Church is a mainline Anglican Christian church found mainly in the United States , but also in Honduras, Taiwan, Colombia, Ecuador, Haiti, the Dominican Republic, Venezuela, the British Virgin Islands and parts of Europe...

 Church near Seabrook, Texas
Seabrook, Texas
Seabrook is a city in Harris county, with some water surface area located within Chambers county in the U.S. state of Texas. The population was 9,443 at the 2000 census....

, but due to the Apollo 8 flight was unable. 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.

Earthrise


When the spacecraft came out from behind the Moon for its fourth pass across the front, the crew witnessed Earthrise for the first time in human history (NASA's Lunar Orbiter 1
Lunar Orbiter 1
The Lunar Orbiter 1 robotic spacecraft, part of the Lunar Orbiter Program, was designed primarily to photograph smooth areas of the lunar surface for selection and verification of safe landing sites for the Surveyor and Apollo missions...

 took the very first picture of an Earthrise from the vicinity of the Moon, on August 23, 1966). Borman saw the Earth emerging from behind the lunar horizon and called in excitement to the others, taking a black-and-white photo as he did so. In the ensuing scramble Anders took the more famous color photo
Earthrise
Earthrise is a famous photograph taken on the 1968 Apollo 8 space mission.Earthrise may also refer to:* Earthrise , a computer game by Interstel...

, later picked by Life magazine as one of its hundred photos of the century. Due to the synchronous rotation
Synchronous rotation
In astronomy, synchronous rotation is a planetological term describing a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit; and therefore always keeps the same hemisphere pointed at the body it is orbiting...

 of the Moon about the Earth, Earthrise is not generally visible from the Lunar surface. Earthrise is generally only visible when orbiting the Moon, other than at selected places near the Moon's limb, where libration
Libration
In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets.-Lunar libration:...

 carries the Earth slightly above and below the lunar horizon.

Anders continued to take photographs while Lovell assumed control of the spacecraft so 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, however, when he started to hear his fellow crew members make mistakes. They were beginning to not understand questions and would have to ask for the answers to be repeated. Borman realized that everyone was extremely tired having not had a good night's sleep in over three days. Taking command, he ordered Anders and Lovell to get some sleep and that the rest of the flight plan regarding observing the Moon be scrubbed. At first Anders protested saying that he was fine, but Borman would not be swayed. At last Anders agreed as long as Borman would set up the camera to continue to take automatic shots 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. On subsequent Apollo missions, crews would avoid this situation by sleeping on the same schedule.
As they rounded the Moon for the ninth time, the second television transmission began. 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." 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 read a section from the Biblical creation story
Apollo 8 Genesis Reading
On December 24, 1968, in what was the most watched television broadcast at the time, the crew of Apollo 8 read in turn from the Book of Genesis as they orbited the moon...

 (verses 1-10) from the Book of Genesis. Borman finished the broadcast
Apollo 8 Genesis Reading
On December 24, 1968, in what was the most watched television broadcast at the time, the crew of Apollo 8 read in turn from the Book of Genesis as they orbited the moon...

 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 8, we close with good night, good luck, a Merry Christmas, and God bless all of you, all of you on the good Earth".

The only task left for the crew at this point was to perform the Trans-Earth Injection (TEI), which was scheduled for 2½ 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.

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
Santa Claus
Santa Claus is a folklore figure in various cultures who distributes gifts to children, normally on Christmas Eve. Each name is a variation of Saint Nicholas, but refers to Santa Claus...

", to which Ken Mattingly
Ken Mattingly
Thomas Kenneth "Ken" Mattingly II, is a retired American astronaut and rear admiral in the United States Navy who flew on the Apollo 16, STS-4 and STS-51-C missions. He had been scheduled to fly on Apollo 13, but was held back due to concerns about a potential illness...

, the current CAPCOM, replied, "That's affirmative, you are the best ones to know". The spacecraft began its journey back to Earth on December 25, Christmas Day.

Unplanned manual re-alignment

Later, Lovell used some otherwise idle time to do some navigational sightings, maneuvering the module to view various stars by using the computer keyboard. However, he accidentally erased some of the computer's memory, which caused the inertial measuring unit (IMU) to think the module was in the same relative position it had been in before lift-off and fire the thrusters to "correct" the module's attitude.

Once the crew realized why the computer had changed the module's attitude, they realized they would have to re-enter data that would tell the computer its real position. It took Lovell ten minutes to figure out the right numbers, using the thrusters to get the stars Rigel
Rigel
Rigel is the brightest star in the constellation Orion and the sixth brightest star in the sky, with visual magnitude 0.18...

 and Sirius
Sirius
Sirius is the brightest star in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The name "Sirius" is derived from the Ancient Greek: Seirios . The star has the Bayer designation Alpha Canis Majoris...

 aligned, and another 15 minutes to enter the corrected data into the computer.

16 months later, Lovell would once again have to perform a similar manual re-alignment, under more critical conditions, during the Apollo 13
Apollo 13
Apollo 13 was the seventh manned mission in the American Apollo space program and the third intended to land on the Moon. The craft was launched on April 11, 1970, at 13:13 CST. The landing was aborted after an oxygen tank exploded two days later, crippling the service module upon which the Command...

 mission, after that module's IMU had to be turned off to conserve energy. In his 1994 book, Lost Moon: The Perilous Voyage of Apollo 13
Lost Moon
Lost Moon: The Perilous Voyage of Apollo 13 , later re-named Apollo 13, is a book written by Jim Lovell and Jeffrey Kluger. It is about the failed Apollo 13 moon landing mission, of which Lovell was the commander...

, Lovell wrote, "My training [on Apollo 8] came in handy!" In that book he dismissed the incident as a "planned experiment", requested by the ground crew. In subsequent interviews Lovell has acknowledged that the incident was an accident, caused by his mistake.

Cruise back to Earth and re-entry

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 re-enter 2½ days after TEI and splash down
Splashdown (spacecraft landing)
Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by American manned spacecraft prior to the Space Shuttle program. It is also possible for the Russian Soyuz spacecraft and Chinese Shenzhou spacecraft to land in water, though this is only a contingency...

 in the Pacific.

On Christmas afternoon, the crew made their fifth television broadcast. This time they gave a tour of the spacecraft, showing how an astronaut lived in space. When they had finished broadcasting they found a small present from Deke Slayton
Deke Slayton
Donald Kent Slayton , better known as Deke Slayton, was an American World War II pilot and later, one of the original NASA Mercury Seven astronauts....

 in the food locker—real turkey with stuffing and three miniature bottles of brandy (which remained unopened; forty years later, Lovell would sell his at a Heritage
Heritage Auctions
Heritage Auction Galleries is the world's largest collectibles auctioneer and the third largest auction house, with over $700 million in annual sales and 600,000 online bidder-members...

 auction for $17,925). 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, in a short four minute broadcast.

After two uneventful days the crew prepared for re-entry. The computer would control the re-entry and all the crew had to do was put the spacecraft in the correct attitude, blunt end forward. If the computer broke down, Borman would take over.

Once the Command Module was separated from the Service Module, the astronauts were committed to re-entry. 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 predicted by the trajectory specialists. As they hit the thin outer atmosphere they noticed it was becoming hazy outside as glowing plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...

 formed around the spacecraft. The spacecraft started slowing down and the deceleration peaked at 6 g (59 m/s2). With the computer controlling the descent by changing the attitude of the spacecraft, Apollo 8 rose briefly like a skipping stone before descending to the ocean. At 30000 feet (9.1 km) the drogue parachute stabilized the spacecraft and was followed at 10000 feet (3 km) by the three main parachutes. The spacecraft splashdown position was estimated to be at 8°6′N 165°1′W in the North Pacific Ocean south of Hawaii.

When it hit the water, the parachutes dragged the spacecraft over and left it upside down, in what was termed Stable 2 position. As they were buffeted by a 10 feet (3 m) swell, Borman was sick, waiting for the three flotation balloons to right the spacecraft. It was 43 minutes after splashdown before the first frogman
Frogman
A frogman is someone who is trained to scuba diving or swim underwater in a military capacity which can include combat. Such personnel are also known by the more formal names of combat diver or combatant diver or combat swimmer....

 from the USS Yorktown
USS Yorktown (CV-10)
USS Yorktown is one of 24 s built during World War II for the United States Navy. She is named after the Battle of Yorktown of the American Revolutionary War, and is the fourth U.S. Navy ship to bear the name...

 arrived, as the spacecraft had landed before sunrise. Forty-five minutes later, the crew was safe on the deck of the aircraft carrier.

Historical importance

Apollo 8 came at the end of 1968, a year that had seen much upheaval in the US. Yet, TIME
Time (magazine)
Time is an American news magazine. A European edition is published from London. Time Europe covers the Middle East, Africa and, since 2003, Latin America. An Asian edition is based in Hong Kong...

magazine chose the crew of Apollo 8 as their Men of the Year
Person of the Year
Person of the Year is an annual issue of the United States newsmagazine Time that features and profiles a person, couple, group, idea, place, or machine that "for better or for worse, ...has done the most to influence the events of the year."- History :The tradition of selecting a Man of the Year...

 for 1968, recognizing them as the people who most influenced events in the preceding year. They had been the first people ever to leave the gravitational influence of the Earth and orbit another celestial body. They had survived a mission that even the crew themselves had rated as only having a fifty-fifty chance of fully succeeding. The effect of Apollo 8 can be summed up by a telegram from a stranger, received by Borman after the mission, that simply stated, "Thank you Apollo 8. You saved 1968."

One of the most famous aspects of the flight was the Earthrise
Earthrise
Earthrise is a famous photograph taken on the 1968 Apollo 8 space mission.Earthrise may also refer to:* Earthrise , a computer game by Interstel...

 picture that was taken as they came around for their fourth orbit of the Moon. This was the first time that humans had taken such a picture whilst actually behind the camera, and it has been credited with a role in inspiring the first Earth Day
Earth Day
Earth Day is a day that is intended to inspire awareness and appreciation for the Earth's natural environment. The name and concept of Earth Day was allegedly pioneered by John McConnell in 1969 at a UNESCO Conference in San Francisco. The first Proclamation of Earth Day was by San Francisco, the...

 in 1970. It was selected as the first of Life magazine's 'hundred photos that changed the world'. Apollo 8 is regarded by some as the most historically significant of all the Apollo missions.

The mission was the most widely covered by the media since the first American orbital flight, Mercury-Atlas 6
Mercury-Atlas 6
Mercury-Atlas 6 was a human spaceflight mission conducted by NASA, the space agency of the United States. As part of Project Mercury, MA-6 was the successful first attempt by NASA to place an astronaut into orbit. The MA-6 mission was launched February 20, 1962. It made three orbits of the Earth,...

 by John Glenn
John Glenn
John Herschel Glenn, Jr. is a former United States Marine Corps pilot, astronaut, and United States senator who was the first American to orbit the Earth and the third American in space. Glenn was a Marine Corps fighter pilot before joining NASA's Mercury program as a member of NASA's original...

 in 1962. There were 1200 journalists covering the mission, with the BBC coverage being broadcast in 54 countries in 15 different languages. The Soviet newspaper Pravda
Pravda
Pravda was a leading newspaper of the Soviet Union and an official organ of the Central Committee of the Communist Party between 1912 and 1991....

featured a quote from Boris Nikolaevich Petrov, Chairman of the Soviet Intercosmos
Intercosmos
Interkosmos was a space program of the Soviet Union designed to include members of military forces of allied Warsaw Pact countries in manned and unmanned missions...

 program, who described the flight as an "outstanding achievement of American space sciences and technology". 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. The Apollo 8 broadcasts won an Emmy, the highest honor given by the Academy of Television Arts and Sciences.

Atheist
Atheism
Atheism is, in a broad sense, the rejection of belief in the existence of deities. In a narrower sense, atheism is specifically the position that there are no deities...

 Madalyn Murray O'Hair
Madalyn Murray O'Hair
Madalyn Murray O'Hair was an American atheist activist and founder of the organization American Atheists and its president from 1963 to 1986. One of her sons, Jon Garth Murray, was the president of the organization from 1986 to 1995, while she remained de facto president during these nine years....

 later caused controversy by bringing a lawsuit against NASA over the reading from Genesis. O'Hair wished the courts to ban US astronauts—who were all government employees—from public prayer in space. Though the case was rejected by the US Supreme Court for lack of jurisdiction, it caused NASA to be skittish about the issue of religion throughout the rest of the Apollo program. Buzz Aldrin, on Apollo 11, self-communicated Presbyterian
Presbyterianism
Presbyterianism refers to a number of Christian churches adhering to the Calvinist theological tradition within Protestantism, which are organized according to a characteristic Presbyterian polity. Presbyterian theology typically emphasizes the sovereignty of God, the authority of the Scriptures,...

 Communion
Eucharist
The Eucharist , also called Holy Communion, the Sacrament of the Altar, the Blessed Sacrament, the Lord's Supper, and other names, is a Christian sacrament or ordinance...

 on the surface of the moon after landing; he refrained from mentioning this publicly for several years, and only obliquely referred to it at the time.

In 1969, the US Postal Service issued a postage stamp (Scott # 1371) commemorating the Apollo 8 flight around the moon. The stamp featured a detail of the famous photograph of the Earthrise
Earthrise
Earthrise is a famous photograph taken on the 1968 Apollo 8 space mission.Earthrise may also refer to:* Earthrise , a computer game by Interstel...

 over the moon taken by Anders on Christmas Eve, and the words, "In the beginning God..."

Spacecraft location

The command module is now displayed at the Chicago Museum of Science and Industry
Museum of Science and Industry (Chicago)
The Museum of Science and Industry is located in Chicago, Illinois, USA in Jackson Park, in the Hyde Park neighborhood adjacent to Lake Michigan. It is housed in the former Palace of Fine Arts from the 1893 World's Columbian Exposition...

, along with a collection of personal items from the flight donated by Lovell and the spacesuit worn by Frank Borman. Jim Lovell's Apollo 8 spacesuit is on public display in the Visitor Center at NASA's Glenn Research Center
Glenn Research Center
NASA John H. Glenn Research Center at Lewis Field is a NASA center, located within the cities of Brook Park, Cleveland and Fairview Park, Ohio between Cleveland Hopkins International Airport and the Cleveland Metroparks's Rocky River Reservation, and has other subsidiary facilities in Ohio...

. Bill Anders' spacesuit is on display at the Science Museum
Science Museum (London)
The Science Museum is one of the three major museums on Exhibition Road, South Kensington, London in the Royal Borough of Kensington and Chelsea. It is part of the National Museum of Science and Industry. The museum is a major London tourist attraction....

 in London, England.

In film

Apollo 8's historic mission has been shown and referred to in several forms, both documentary and fiction. The various television transmissions and 16 mm footage shot by the crew of Apollo 8 was compiled and released by NASA in the 1969 documentary, Debrief: Apollo 8, which was hosted by Burgess Meredith
Burgess Meredith
Oliver Burgess Meredith , known professionally as Burgess Meredith, was an American actor in theatre, film, and television, who also worked as a director...

. In addition, Spacecraft Films released, in 2003, a three-disc DVD set containing all of NASA's TV and 16mm film footage related to the mission including all TV transmissions from space, training and launch footage, and motion pictures taken in flight. Portions of the Apollo 8 Mission can be seen in the 1989 documentary For All Mankind
For All Mankind
For All Mankind is a 1989 documentary film documenting the Apollo missions of NASA. It was directed by Al Reinert.Music for the film was originally composed in 1983 by Brian Eno and released as an album entitled Apollo: Atmospheres and Soundtracks...

, which won the Grand Jury Prize at the Sundance Film Festival for Outstanding Documentary. The Apollo 8 mission was well covered in the British documentary: 'In the Shadow of the Moon'.

Portions of the Apollo 8 mission are dramatized in the miniseries From the Earth to the Moon episode "1968". The S-IVB stage of Apollo 8 was also portrayed as the location of an alien device in the 1970 UFO
UFO (TV series)
UFO is a 1970-1971 British television science fiction series about an alien invasion of Earth, created by Gerry Anderson and Sylvia Anderson with Reg Hill, and produced by the Andersons and Lew Grade's Century 21 Productions for Grade's ITC Entertainment company.UFO first aired in the UK and Canada...

episode "Conflict".

See also

  • List of Apollo astronauts
  • Space Race
    Space Race
    The Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...

  • Splashdown (spacecraft landing)
    Splashdown (spacecraft landing)
    Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by American manned spacecraft prior to the Space Shuttle program. It is also possible for the Russian Soyuz spacecraft and Chinese Shenzhou spacecraft to land in water, though this is only a contingency...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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