Apollo program

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Apollo program logo
The Lunar Module of Apollo 15 and the astronaut Irwin and the moon car ( Lunar Roving Vehicle )

The Apollo program was a US space project . With the Apollo spaceships, it brought people to the moon for the first time and so far only . The program was operated by the National Aeronautics and Space Administration ( NASA ) between 1961 and 1972.

In several steps, NASA tested techniques that would be important for a moon landing , such as As the navigation and coupling of spacecraft in space or leaving a space ship in the space suit . Many important tests were carried out in preparation in the Gemini program . The first manned moon landing was on July 20, 1969 with the Apollo 11 mission . After five more landings - the last one in 1972 with Apollo 17 - the program was discontinued (also) for cost reasons. Since then no one has set foot on the moon, but several countries are pursuing new manned lunar programs.


The name "Apollo" was an idea of ​​the NASA manager Abe Silverstein , at that time head of the department for space programs (Office of Space Flight Programs). He was referring to the god Apollo of Greek mythology , who was considered to be the driver of the sun chariot and an accurate archer. Internally, the name was approved by NASA Director Glennan on July 9, 1960. The name was publicly announced by NASA's deputy head, Hugh Latimer Dryden, on July 28, 1960 at the opening of a NASA conference with representatives from the space industry.


Early draft configuration for a direct flight or EOR concept (NASA, 1961)

In July 1960, before the Mercury program began to show its first success, a conference was held in Washington at which NASA and various industrial companies worked out a long-term plan for space travel. A manned orbit around the moon was planned, at this point there was no mention of a landing.

The configuration of the moon flight was initially unclear. The first plans in the 1960s envisaged a single spaceship to land on the moon and return to earth, as it was unclear whether a rendezvous maneuver and the coupling of two spacecraft would be possible. More detailed studies assumed four possible strategies:

  • Direct flight: A single rocket starts with the spaceship, which lands as a whole on the moon and (as a whole or just the top) returns to earth.
  • Assembly in earth orbit ( EOR - Earth Orbit Rendezvous): The components of the missions are started individually and assembled in earth orbit, here too the entire spaceship lands on the moon.
  • Lunar Orbit Rendezvous ( LOR ): In lunar orbit, the spacecraft separates a piece of land that flies to the moon. A rendezvous and transfer maneuver is required for this after the ascent again.
  • Supply ship on the moon ( LSR - Lunar Surface Rendezvous): In this concept, an unmanned supply ship would have to be brought to the moon beforehand. The manned mission should have landed here to pick up the fuel for the return voyage.

The last concept was the first to be discarded. It also soon became apparent that the plans for a direct flight were unrealistic, as the carrier system required for this would have to have been many times larger than the Saturn V. The EOR concept, which would have required a large number of rockets (one spoke of up to 15 launches per moon flight), was associated with additional work and costs. In particular, at the instigation of John C. Houbolt , who stubbornly defended the initial minority opinion LOR and without regard to hierarchies, a more complex but optimized configuration of separate spacecraft was adopted at the end of 1961. This not only made it possible to get by with a single rocket, but also allowed the individual components to be optimized for their precise purpose.


The actual NASA plan provided for seven missions before the first manned moon landing. These were missions A through G:

  • Mission A: Unmanned test of the Saturn V and the Apollo spacecraft in earth orbit (carried out twice with Apollo 4 and Apollo 6 ).
  • Mission B: Unmanned test of the lunar module (LM for Lunar Module) (carried out with Apollo 5 ).
  • Mission C: Manned test of the Apollo spacecraft in earth orbit (carried out with Apollo 7 ).
  • Mission D: Test of the combination of command module and lander in a near-earth orbit (originally intended as Apollo 8, renumbered as Apollo 9 because a moon flight (Mission C ') was inserted as Apollo 8 ).
  • Mission E: Test of the combination of command module and lander in a distant orbit (mission was canceled, crew took over mission C ').
  • Mission F: Test of the combination of command module and lander in a lunar orbit (carried out with Apollo 10 ).
  • Mission G: First landing on the moon (carried out with Apollo 11 ).

The first orbit around the moon carried out with Apollo 8 , Christmas 1968, was actually not planned by NASA and was called Mission C 'between missions C and D.

In addition, missions H, I and J were planned:

  • Mission H: landing on the moon with advanced scientific experiments (performed with Apollo 12 and Apollo 14 . Apollo 13 unsuccessful; Apollo 15 was originally intended also as H-mission).
  • Mission I: Manned flights in lunar orbit for research purposes; no landing intended. There were no concrete plans for I missions.
  • Mission J: landing on the moon with extended scientific experiments and the moon rover (carried out with Apollo 15 , Apollo 16 and Apollo 17 ).

Effort and costs

The Apollo program cost 23.9 billion dollars , about 120 billion by today's standards (2009), and employed up to 400,000 people.

Race of systems

With the start of Sputnik 1 in 1957, the first unmanned hard moon landing in 1959 by Lunik 2 and the first manned space flight by Yuri Gagarin with Vostok 1 in April 1961, the Soviet Union had risen to become the leading space nation at the beginning of the space age . The US was looking for an area in space travel where it could beat the Soviet Union. The manned moon landing was considered suitable for this.

The US Apollo program

On May 25, 1961, a month and a half after the flight from Gagarin, President John F. Kennedy gave a famous speech to the US Congress in which he set his nation the task of landing people on the moon in the same decade and safely back to earth. The following words gave the starting signal for the Apollo program:

“I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. No single space project in this period will be more impressive to mankind or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. "

“I believe this country should devote itself to the goal of landing a person on the moon and bringing them back safely to earth before the end of this decade. Not a single space project will impress mankind more or be more important for the exploration of distant space during this period; and none will be so difficult or expensive to achieve. "

With the cooperation of the German-born engineer Wernher von Braun , director of the Marshall Space Flight Center in Huntsville (Alabama) , the largest rocket to date was built for the manned moon flight. All of the Saturn V launches were successful despite their great power and complexity, which is quite remarkable, since most of the other rocket systems such as the Redstone , Thor and Atlas also had false starts.

The MIT Instrumentation Laboratory developed a special inertial navigation system for the Apollo spacecraft , the so-called Primary Guidance, Navigation and Control System (PGNCS, pronounced: pings ). The Apollo Guidance Computer (AGC) contained therein was the first device in which integrated circuits (IC) were used. The Project FIRE should technologies for the necessary heat shield of the Apollo Command Module develop and test.

In preparation for the moon landing, the Gemini program ran parallel to the Apollo program , with which experience in rendezvous maneuvers , navigation and work outside of a spacecraft in space ( extra-vehicular activity , EVA) was to be gained.

On January 27, 1967, the Apollo program suffered a serious setback: During ground tests, a fire broke out in the Apollo command module CM 012 , in which the three astronauts Gus Grissom , Ed White and Roger Chaffee were killed. The missile was not fueled during these tests. The command capsule was not filled with ordinary air, but with pure oxygen at positive atmospheric pressure. As a result, in less than a minute, a small electrical spark turned into a fire that killed the men. Extensive changes to the command module were the result. The test was subsequently given the name Apollo 1 .

Nevertheless, Kennedy's task for the US nation to get a person to the moon and safely back to earth in the 1960s was achieved with the successful moon landing of Apollo 11 on July 20, 1969. Although further launches were originally planned, the program was ended after the sixth successful moon landing ( Apollo 17 ).

The manned lunar program of the Soviet Union

At the same time as the Apollo program, Soviet space travel was also working to put people on the moon. With the Zond probes, modified Soyuz spaceships were launched unmanned to the moon and brought back to earth after one orbit. This was used to test the spaceship , which was intended for a subsequent manned flight to the moon. Zond-5 orbited the moon in September 1968, but came off course on its return and had to be salvaged from the Indian Ocean, the landing was actually planned for Soviet territory. In October 1970 the test program with Zond-8 was ended.

At the same time, the Soviet Union was also working on a rocket for a moon landing mission, which, similar to Apollo, was to be launched with a single rocket. The N1 missile was developed for this purpose. However, in all four test launches, which took place between 1969 and 1972, it exploded before reaching Earth orbit. As a result, and given the fact that the Americans had already successfully landed on the moon, the Soviet Union abandoned its manned lunar program. It was only after the collapse of the Soviet Union in the early 1990s that detailed information about this program and the N1 missile became public.

Moon landings

Neil Armstrong becomes the first person on the moon
BootPrint of Buzz Aldrin on the moon (Apollo 11), taken with a Biogon - lens from Carl Zeiss
Landing points of the Apolloland ferries

The first two people landed on the moon as part of the Apollo 11 mission on July 20, 1969 at 9:17 pm ( CET ) : Neil Armstrong and Buzz Aldrin . Six hours later, on July 21 at 3:56:20 a.m.CET, Neil Armstrong was the first person to walk on the moon at Mare Tranquillitatis. He spoke the now famous sentence:

“That's one small step for [a] man, one giant leap for mankind. ( listen to ? / i ) ” Audio file / audio sample

"This is a small step for a human, a big leap for humanity."

The "a" before "man" was added in later texts to preserve the sense, although it was not heard over the radio. Armstrong was later asked if he actually hadn't said it, but he couldn't remember it. It therefore remains unclear whether it was lost due to interference in radio traffic or whether it was actually not said.

The third astronaut, Michael Collins , circled Earth's satellite in the Apollo mother ship until the Eagle lander returned .

A total of six moon landings were carried out as part of the Apollo program. To date, 12 people, all of them US Americans, have set foot on the moon. Harrison H. Schmitt - Apollo 17 lunar shuttle pilot - was the last person to set foot on the lunar soil on December 12, 1972. Eugene Cernan - Apollo 17 commander - is so far the last person to have been on the moon by being the last to board the lunar module. In July 2009, the lunar probe Lunar Reconnaissance Orbiter transmitted images of the landing sites of Apollo 11, 14, 15, 16 and 17.

The "successful failure" of Apollo 13

As a routine flight, hardly noticed by the public, the astronauts Jim Lovell , Jack Swigert and Fred Haise took off with Apollo 13 on April 11, 1970 . It was not until a tank with liquid oxygen in the service module exploded on the way to the moon, threatening the lives of the three men, that the entire world became aware of the mission. The astronauts were only able to save themselves by using the lunar module as a “lifeboat”. A moon landing was out of the question.

Since the spaceship had already left the earth's orbit towards the moon at the time of the accident and the fuel would not have been by far sufficient for an immediate direct reversal, the only way back to earth was around the moon, with the spaceship swinging by - Maneuver was accelerated back towards earth with the help of the lunar attraction. After circumnavigating the moon and almost 88 hours after the accident, it landed in the Pacific on April 17, 1970 . Curiously, when they orbited the moon, the members of the crew of Apollo 13 were the people who were furthest from Earth so far, albeit unplanned. Despite the failed moon landing, Apollo 13 is still considered a success because it was the first time it was possible to bring astronauts back to earth alive in an emergency in space. Commander Jim Lovell later described the course of the only mission of the Apollo program that had to be prematurely canceled as a "successful failure". Flight director Gene Kranz called it "NASA's finest hour".

The 1995 film Apollo 13 with Tom Hanks in the role of Jim Lovell is about the dramatic events .

Typical course of the Apollo mission

Start of the Apollo 8 mission
  • Start at Kennedy Space Center
  • After about two and a half minutes, the 1st stage S-IC was disconnected at an altitude of about 56 km; H. in the high stratosphere (speed approx. 10,000 km / h - Mach  8)
  • Immediately afterwards ignition of the 2nd stage S-II
  • Shortly afterwards, separation of the engine skirt (officially called interstage )
  • Three minutes and 25 seconds after the start of separation of the rescue missile system (launch escape tower)
  • Separation of the 2nd stage at a height of approx. 185 km (speed approx. 24,000 km / h) including the conical adapter for the 3rd stage
  • Immediately afterwards ignition of the 3rd stage S-IVB, swiveling into a near earth orbit (speed approx. 28,000 km / h), switch-off of the 3rd stage
  • After a few orbits of the earth, reignition of the 3rd stage ( TLI , trans-lunar injection ), expansion of the orbit to the moon (contrary to a common assumption that the escape speed was not exceeded and flight from the earth ( Apollo 8 reached 10.82 km / s - approx. 39,000 km / h - even on the moon you are still in an earth orbit )). What was critical with the TLI , however, was the time that had to pass after the J-2 engine had burned out for the first time and re-ignited.
  • Separation of the Apollo spacecraft from the 3rd stage in several steps ( TDM , transposition and docking maneuver ):
    • Separation of the command / service module ( CSM , command / service module ) from the step adapter ( SLA , spacecraft lunar module adapter ) on the third level
    • Opening and ejection of the stage adapter - he had been the Lunar Module ( LM , lunar module enclosed)
    • 180 ° rotation of the command / supply module so that its bow can be coupled to the lander
    • Pulling the lander out of its parking bay in the third stage
    • The third stage, the last part of the Saturn V rocket, has had its day at this point. Controlled from the control center, it is disposed of (i.e. maneuvered into solar orbit or put on a collision course with the moon for seismic investigations)
  • Driveless flight to the moon, possibly corrective maneuvers
  • Ignition of the engine of the supply module for pivoting into lunar orbit ( LOI , lunar orbit insertion ) on the back of the moon
  • Two astronauts transfer to the lander; the command / supply module remains in lunar orbit with one astronaut
  • Uncoupling of the lander, ignition of the landing engine in order to achieve an elliptical lunar orbit ( DOI , descent orbit initiation ) on the back of the moon
  • Descent to the surface of the moon and landing
  • Moon landing in the narrow sense: Astronauts perform activities outside of the spacecraft by ( spacewalk , extra vehicular activity / EVA ), d. H. they explore the surface of the moon on foot or on later missions by moon car
  • Meanwhile: the command / supply module orbits the moon, cameras and other instruments in the supply module examine the moon, the astronaut carries out observations and checks possible landing sites for later missions
  • Start from the surface of the moon. The descent stage serves as a launch pad and remains on the surface with a flag, camera, car and various other equipment. The astronauts and the rock samples fly into lunar orbit in the ascent stage .
  • Rendezvous with the command / supply module, docking, transferring the astronauts, dropping the ascent stage
  • Ignition of the engine of the supply module ( TEI , trans-earth injection ) to leave the lunar orbit on the back of the moon
  • Drive back to earth without drive, if necessary corrective maneuvers
  • EVA to recover the films from the cameras in the supply module (for the Apollo 15 to 17 missions)
  • Ejection of the supply module , alignment of the command module for re-entry
  • Re-entry into the earth's atmosphere including about three minutes of radio silence ( blackout ) , as the frictional heat causes the spaceship to pull a beam of hot, ionized air behind it, which hinders radio communication
  • Use of high-speed parachutes (drogue parachutes)
  • Dropping of the high-speed parachutes , use of the pilot and main parachutes , which can be clearly seen on pictures of the landings as three red and white, round umbrellas
  • Drowning in the landing area
  • Dropping the main parachutes
  • If the command module should lie with the pointed side down in the water (position "stable two" ): Use the uprighting system , d. H. Inflating the gas bags, which are reminiscent of oversized footballs and which are also clearly visible in the pictures
  • Recovery by an aircraft carrier ; for several missions with the help of the Helicopter 66
  • During the first missions (up to Apollo 14), the astronauts and rock samples remained in quarantine for several weeks for safety reasons

Apollo missions

mission Takeoff and
Duration commander Apollo spacecraft pilot Lunar module pilot Mission objective / remark
Apollo program logo
26, 1966 Feb. 26, 1966
00d 00h 37m 20s unmanned First start of the Saturn IB , suborbital test flight of the Apollo command module
Apollo program logo
0Jul 5, 1966
0Jul 5, 1966
00d 05h 59m 47s unmanned First orbital launch of the Saturn IB , test flight without an Apollo spacecraft
Apollo program logo
25, 1966 Aug 25, 1966
00d 01h 33m 02s unmanned suborbital test flight of the Apollo command module
Apollo 1
Apollo 1 logo
(Jan. 27, 1967)
no start
Virgil Grissom Edward White Roger Chaffee On January 27, 1967, a fire broke out on the launch table in a pure oxygen atmosphere in the cabin during a ground test, killing all three astronauts.
Apollo 4
Apollo program logo
09, 1967 Nov 9, 1967
00d 08h 36m 59s unmanned First start of the Saturn V , test flight of the Apollo command module
Apollo 5
Apollo program logo
Jan. 22, 1968 unmanned Test flight of the lunar module
Apollo 6
Apollo program logo
0Apr 4, 1968 00d 10h 22m 59s unmanned Second start of the Saturn V, test flight
Apollo 7
Apollo 7 logo
Oct 11, 1968
Oct 22, 1968
10d 20h 09m 03s Walter Schirra Donn Eisele Walter Cunningham First manned start of the Saturn 1B . Tests in Earth orbit without a lunar module - first television broadcast during a US space mission
Apollo 8
Apollo 8 logo
Dec 21, 1968
Dec 27, 1968
06d 03h 00m 42s Frank Borman James Lovell William Anders First manned launch of Saturn V and first flight of humans to the moon, which they circled 10 times. Since they did not have a lunar module, Anders took on the duties of a flight engineer and photographer
Apollo 9
Apollo 9 logo
0March 3, 1969
March 13, 1969
10d 01h 00m 54s James McDivitt David Scott Russell Schweickart Tests of the Lunar Module in Earth Orbit - Rendezvous and Docking
Apollo 10
Apollo 10 logo
May 18, 1969
May 26, 1969
08d 00h 03m 23s Tom Stafford John Young Eugene Cernan Test of the lunar module in lunar orbit, approaches the lunar surface up to 14 km
Apollo 11
Apollo 11 logo
Jul 16, 1969
Jul 24, 1969
08d 03h 18m 35s Neil Armstrong Michael Collins Buzz Aldrin First moon landing Landing
site: Mare Tranquillitatis
Apollo 12
Apollo 12 logo
Nov 14, 1969
Nov 24, 1969
10d  04h 36m 25s Charles Conrad Richard Gordon Alan Bean Landing at the Surveyor 3 probe launched in 1967. Landing
site: Oceanus Procellarum
Apollo 13
Apollo 13 logo
Apr 11, 1970
Apr 17, 1970
05d 22h 54m 41s James Lovell John Swigert Fred Haise Explosion of an oxygen tank in the service module (SM) and leak in the outer shell of the SM, abortion of the mission, the cabin of the lunar module (LM) temporarily served the crew as a "lifeboat", swing-by maneuvers on the moon - no moon landing
Planned landing site: Fra Mauro
Apollo 14
Apollo 14 logo
Jan. 31, 1971
0Feb. 9, 1971
09d 00h 01m 58s Alan Shepard Stuart Roosa Edgar Mitchell Successful landing on the original landing site of Apollo 13, use of a handcart ( MET )
Landing site: Fra Mauro
Apollo 15
Apollo 15 logo
Jul 26, 1971
0Aug 7, 1971
12d 07h 11m 53s David Scott Alfred Worden James Irwin First mission with the moon car Lunar Roving Vehicle
Landing site: Hadley-Rille
Apollo 16
Apollo 16 logo
Apr 16, 1972
Apr 27, 1972
11d 01h 51m 05s John Young Thomas Mattingly Charles Duke First investigation of a plateau, use of UV camera, moon car
landing site: Descartes
Apollo 17
Apollo 17 logo
0Dec. 7, 1972
Dec. 19, 1972
12d 13h 51m 59s Eugene Cernan Ronald Evans Harrison Schmitt Last moon landing, moon car, Orange Soil found
Landing site: Taurus-Littrow

Shortly after the successful moon landing of Apollo 11, NASA published the further planning, which provided for nine more Apollo flights by the end of 1972. But in January 1970, before the delay caused by the breakdown of Apollo 13 , Apollo 20 was canceled for reasons of cost. In September 1970 the original Apollo 15 mission and Apollo 19 were also saved. The missions Apollo 16, Apollo 17 and Apollo 18, which were not removed from the program, were then renamed Apollo 15 , Apollo 16 and Apollo 17 .

The Apollo spaceships and Saturn rockets that remained after the completion of the moon flights were used for the Skylab project in 1973/74 and the Apollo-Soyuz test project in 1975.

mission Takeoff and
Duration Crew
(CDR: commander,
CMP: pilot of the Apollo spacecraft,
SCI: science astronaut,
DMP: pilot of the docking module)
Skylab 1
Skylab Program Patch.png
May 14, 1973
Jul 11, 1979
unmanned Start of the Skylab station, damage to the solar cell boom,
carrier system: Saturn V
6 years after the end of the Skylab missions it burned up when it entered the earth's atmosphere
Skylab 2
May 25, 1973
June 22, 1973
28d  00h 49m 49s Charles Conrad (CDR),
Paul Weitz (CMP),
Joseph Kerwin (SCI)
First crew of Skylab, repair of solar cells and heat shield,
carrier system: Saturn 1B
Skylab 3
Jul 28, 1973
Sep 25 1973
59d 01h 09m 04s Alan Bean (CDR),
Jack Lousma (CMP),
Owen Garriott (SCI)
Second crew to Skylab, repair of heat shield,
carrier system: Saturn 1B
Skylab 4
Nov. 16, 1973
0Feb. 8, 1974
84d 01h 16m 00s Gerald Carr (CDR),
William Pogue (CMP),
Edward Gibson (SCI)
Third crew Skylab,
carrier system: Saturn 1B
Apollo Soyuz
Test Project

ASTP patch.png
Jul 15, 1975
Jul 24, 1975
09d 01h 28m 00s Tom Stafford (CDR),
Vance Brand (CMP),
Deke Slayton (DMP)
Coupling with Soyuz 19 (crew: Alexei Leonow , Valeri Kubassow ),
carrier system: Saturn 1B


The Apollo program is often accused of insufficient scientific benefit. The ex-mission member William Anders said that Apollo was “not a scientific program”, in truth it was a “battle in the Cold War”. "Sure, we collected a few rocks and took a few photos, but had it not been for this race with the Russians, we would never have had the support of the taxpayers." After the success of Apollo 11, some researchers at NASA, including them, quit the then NASA chief geologist Eugene Shoemaker . He took the position that the scientific yield from unmanned probes could have been achieved at a fifth of the cost and 3 to 4 years earlier.

The main focus of the astronauts' scientific work on the moon was geology. A total of 382 kilograms of lunar rock were returned to Earth on the six missions.

Other projects were, for example, the University of Bern's Solar Wind Composition Experiment , which was taken to the moon five times, and the setting up of reflectors for measurement purposes.

conspiracy theories

As with many events of such great political importance, the moon landings became the object of numerous conspiracy theories . These assume that the moon landings did not take place in the years 1969 to 1972 (often it is only about the first manned moon landing), but were simulated by NASA and the US government. The conspiracy theories have been spreading since the 1970s, through the author Bill Kaysing , but increasingly since 2001. None of the conspiracy theories provides a comprehensible, scientifically tenable doubt about the moon landings.

See also


in order of appearance

  • Jesco von Puttkamer : Apollo 8, departure into space. The report of the first orbit around the moon . Heyne, Munich 1969.
  • Andrew Chaikin: A Man on the Moon . Penguin Books, London 1995, ISBN 0-14-027201-1 .
  • W. Henry Lambright: Powering Apollo. James E. Webb of NASA . Johns Hopkins University Press, Baltimore 1995, ISBN 0-8018-4902-0 .
  • David M. Harland: Exploring the Moon . Springer, London 1999, ISBN 1-85233-099-6 .
  • Robert Godwin (ed.): Apollo. The NASA mission reports (11 volumes for Apollo 7 to 17). Apogee Books, Burlington 1999-2002.
  • Eugene Cernan: The Last Man on the Moon. Astronaut Eugene Cernan and America's race in space . St. Martin's Griffin, New York 2000, ISBN 0-312-26351-1 .
  • Jesco von Puttkamer: Apollo 11: "We see the earth". The way from Apollo 11 to the international space station . Herbig, Munich 2001, ISBN 3-7766-2097-8 .
  • Thomas J. Kelly: Moon Lander: How We Developed the Apollo Lunar Module . Smithsonian Books, Washington, DC 2001, ISBN 1-56098-998-X .
  • André Hoffmann: The long way to the moon . Athene Media, Dinslaken 2009, ISBN 978-3-86992-148-8 .
  • Cortright, Edgar M .: Apollo Expeditions to the Moon. The NASA History . Dover, Mineola 2010, ISBN 978-0-486-47175-4 .
  • Thorsten Dambeck: The Apollo Project. The whole story - with original NASA recordings . Kosmos Verlag, Stuttgart 2019, ISBN 978-3-440-16279-8 .


Web links

Individual evidence

  1. Helen T. Wells, Susan H. Whiteley, Carrie E. Karegeannes: Origins of NASA Names (=  The NASA History Series . SP-4402). NASA History Office, Washington, DC 1976, chap. 4 , p. 99 (English, nasa.gov [accessed February 15, 2020]).
  2. ^ Richard Jurek: The Ultimate Engineer . The Remarkable Life of NASA's Visionary Leader George M. Low. U of Nebraska Press, 2019, ISBN 978-1-4962-1849-0 , pp. 72 (English, google.de [accessed February 15, 2020]).
  3. ^ Courtney G Brooks, James M. Grimwood, Loyd S. Swenson: Chariots for Apollo . A History of Manned Lunar Spacecraft (=  The NASA History Series . SP-4205). NASA History Office, Washington, DC 1979, chap. 1 , p. 15 (English, nasa.gov [accessed February 15, 2020]).
  4. ^ John Noble Wilford: We Reach the Moon: The New York Times Story of Man's Greatest Adventure . Bantam Paperbacks, New York 1969. p. 67.
  5. Detlef Borchers: 40 Years Ago: A Small Step , heise.de, July 20, 2009, accessed on July 30, 2015
  6. Video excerpt from Kennedy's speech ( MPG , 881 kB)
  7. LRO See's Apollo Landing Sites. In: Lunar Reconnaissance Orbiter. nasa.gov, July 17, 2009; accessed March 5, 2011 .
  8. NASA's “finest hour”. In: nasa.gov. April 2010, accessed September 28, 2019 .
  9. Apollo Flight Journal Apollo 8
  10. http://www.pro-physik.de/details/news/1120525/Die_zwei_Seiten_der_Mondlandung.html
  11. Christoph Seidler: 50 years "Apollo 11" landing What the moonstones reveal . Spiegel Online, July 22, 2019