Apollo 11
Apollo 11 was the fifth manned flight in the United States Apollo program and the first spaceflight to land humans on the Moon. Commander Neil Armstrong and Lunar Module Pilot Edwin "Buzz" Aldrin landed the Lunar Module Eagle on July 20 at 20:17UTC, and Armstrong became the first person to step onto the surface about six hours later, at 02:56UTC on July 21. Aldrin joined him 19 minutes afterward, and together they spent about two and a half hours exploring the site they had named Tranquility Base upon landing. They collected of lunar material before re-entering the Lunar Module. In total, they were on the Moon’s surface for 21 hours, 36 minutes before returning to the Command Module Columbia, which remained in lunar orbit, piloted by Michael Collins.
Apollo 11 was launched by a Saturn V rocket from Kennedy Space Center in Florida, on July 16 at 13:32UTC. The Apollo spacecraft consisted of three parts: the command module, which housed the three astronauts and was the only part to return to Earth; the service module providing propulsion, electrical power, oxygen, and water to the command module; and the Lunar Module, which had two stages—a descent stage with a large engine and fuel tanks for landing on the Moon, and a lighter ascent stage containing a cabin for two astronauts and a small engine to return them to lunar orbit.
After being sent to the Moon by the Saturn V's third stage, the astronauts separated the spacecraft and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved into Eagle and landed in the Mare Tranquillitatis on July 20. The astronauts used Eagles ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned Eagle before performing the maneuvers that propelled Columbia out of the last of its 30 lunar orbits onto a trajectory back to Earth. They returned to Earth and splashed down in the Pacific Ocean on July 24 at 16:35:35UTC, after more than eight days in space.
Armstrong's first step onto the lunar surface was broadcast on live television to a worldwide audience. He described it as "one small step for man, one giant leap for mankind." Apollo 11 provided a U.S. victory in the Space Race against the Soviet Union, and fulfilled the national goal set in 1961 by President John F. Kennedy: "before this decade is out, of landing a man on the Moon and returning him safely to the Earth".
Background
In the late 1950s and early 1960s, the United States was engaged in the Cold War, a geopolitical rivalry with the Soviet Union. On October 4, 1957, the Soviet Union launched Sputnik 1, the first artificial satellite, surprising the world and fueling fears about Soviet technological and military capabilities. Its success demonstrated that the USSR could potentially deliver nuclear weapons over intercontinental distances, challenging American claims of military, economic, and technological superiority. This incident sparked the Sputnik crisis and ignited the Space Race, as both superpowers sought to demonstrate superiority in spaceflight. President Dwight D. Eisenhower responded to the challenge posed by Sputnik by creating the National Aeronautics and Space Administration, and initiating Project Mercury, which aimed to place a man into Earth orbit. The Soviets took the lead on April 12, 1961, when cosmonaut Yuri Gagarin became the first person in space and the first to orbit the Earth. Nearly a month later, on May 5, 1961, Alan Shepard became the first American in space; his 15-minute flight was suborbital, not a full orbit.Because the Soviet Union had launch vehicles with higher lift capacity, President John F. Kennedy, Eisenhower's successor, chose a challenge that exceeded the capabilities of the existing generation of rockets, so that both countries would be starting from an equal position. A crewed mission to the Moon would serve this purpose.
On May 25, 1961, Kennedy addressed the United States Congress on "Urgent National Needs" and declared:
On September 12, 1962, Kennedy delivered another speech before a crowd of about 40,000 people in the Rice University football stadium in Houston, Texas. A widely quoted refrain from the middle portion of the speech reads as follows:
File:John F. Kennedy speaks at Rice University.jpg|thumb|left|upright|alt=Kennedy, in a blue suit and tie, speaks at a wooden podium bearing the seal of the President of the United States. Vice President Lyndon Johnson and other dignitaries stand behind him.|President John F. Kennedy speaking at Rice University on September 12, 1962
In spite of that, the proposed program faced widespread opposition and was dubbed a "moondoggle" by Norbert Wiener, a mathematician at the Massachusetts Institute of Technology. The effort to land a man on the Moon already had a name: Project Apollo. When Kennedy met with Nikita Khrushchev, the Premier of the Soviet Union in June 1961, he proposed making the Moon landing a joint project, but Khrushchev declined the offer. Kennedy again proposed a joint expedition to the Moon in a speech to the United Nations General Assembly on September 20, 1963. The idea of a joint Moon mission was ultimately abandoned after Kennedy's death.
An early and crucial decision was choosing lunar orbit rendezvous over both direct ascent and Earth orbit rendezvous. A space rendezvous is an orbital maneuver in which two spacecraft navigate through space and meet up. In July 1962, NASA head James Webb announced that lunar orbit rendezvous would be used and that the Apollo spacecraft would have three major parts: a command module with a cabin for the three astronauts, and the only part that returned to Earth; a service module, which supported the command module with propulsion, electrical power, oxygen, and water; and a lunar module that had two stages—a descent stage for landing on the Moon, and an ascent stage to place the astronauts back into lunar orbit. This design meant the spacecraft could be launched by a single Saturn V rocket that was then under development.
Technologies and techniques required for Apollo were developed by Project Gemini. The Apollo project was enabled by NASA's adoption of new advances in semiconductor device, including metal–oxide–semiconductor field-effect transistors in the Interplanetary Monitoring Platform and silicon integrated circuit chips in the Apollo Guidance Computer.
Project Apollo was abruptly halted by the Apollo 1 fire on January 27, 1967, in which astronauts Gus Grissom, Ed White, and Roger B. Chaffee died, and the subsequent investigation. In October 1968, Apollo 7 evaluated the command module in Earth orbit, and in December Apollo 8 tested it in lunar orbit. In March 1969, Apollo 9 put the lunar module through its paces in Earth orbit, and in May Apollo 10 conducted a "dress rehearsal" in lunar orbit. By July 1969, all was in readiness for Apollo 11 to take the final step onto the Moon.
The Soviet Union appeared to be winning the Space Race, but its early lead was overtaken by the US Gemini program and Soviet failure to develop the N1 launcher, which would have been comparable to the Saturn V. Seeing these failures, the Soviets then attempted to beat the US to return lunar material to the Earth by means of uncrewed probes. On July 13, three days before Apollo 11's launch, the Soviet Union launched Luna 15, which reached lunar orbit before Apollo 11. During descent, a malfunction caused Luna 15 to crash in Mare Crisium about two hours before Armstrong and Aldrin took off from the Moon's surface to return to earth. The Nuffield Radio Astronomy Laboratories radio telescope in England recorded transmissions from Luna 15 during its descent, and these were released in July 2009 for the 40th anniversary of Apollo 11.
Personnel
Prime crew
The initial crew assignment of Commander Neil Armstrong, Command Module Pilot Jim Lovell, and Lunar Module Pilot Buzz Aldrin on the backup crew for Apollo 9 was officially announced on November 20, 1967. Lovell and Aldrin had previously flown together as the crew of Gemini 12. Due to design and manufacturing delays in the LM, Apollo 8 and Apollo 9 swapped prime and backup crews, and Armstrong's crew became the backup for Apollo 8. Based on the normal crew rotation scheme, Armstrong was then expected to command Apollo 11.There would be one change. Michael Collins, the CMP on the Apollo 8 crew, began experiencing trouble with his legs. Doctors diagnosed a bony growth between his fifth and sixth vertebrae, requiring surgery. Lovell took his place on the Apollo 8 crew, and when Collins recovered he joined Armstrong's crew as CMP. In the meantime, Fred Haise filled in as backup LMP, and Aldrin as backup CMP for Apollo 8. Apollo 11 was the second American mission where all the crew members had prior spaceflight experience, the first being Apollo 10. The next was STS-26 in 1988.
Deke Slayton gave Armstrong the option to replace Aldrin with Lovell, since some thought Aldrin was difficult to work with. Armstrong had no issues working with Aldrin but thought it over for a day before declining. He thought Lovell deserved to command his own mission.
The Apollo 11 prime crew had none of the close cheerful camaraderie characterized by that of Apollo 12. Instead, they forged an amiable working relationship. Armstrong in particular was notoriously aloof, but Collins, who considered himself a loner, confessed to rebuffing Aldrin's attempts to create a more personal relationship. Aldrin and Collins described the crew as "amiable strangers". Armstrong did not agree with the assessment, and said "all the crews I was on worked very well together."
Backup crew
The backup crew consisted of Lovell as Commander, William Anders as CMP, and Haise as LMP. Anders had flown with Lovell on Apollo 8. In early 1969, Anders accepted a job with the National Aeronautics and Space Council effective August 1969, and announced he would retire as an astronaut at that time. Ken Mattingly was moved from the support crew into parallel training with Anders as backup CMP in case Apollo 11 was delayed past its intended July launch date, at which point Anders would be unavailable.Under the normal Apollo crew rotation, Lovell, Mattingly, and Haise would have been assigned to Apollo 14. However, because Alan Shepard had only recently returned to flight status and needed additional training, NASA reassigned his crew to Apollo 14 and moved Lovell's crew up to fly Apollo 13 instead. Shortly before launch, Mattingly was replaced by Jack Swigert due to concerns over possible measles exposure.