Apollo 11 Moon Landing (1969): The First Humans on the Moon

The Apollo 11 Moon landing in July 1969 was the first time human beings set foot on another world. On 20 July 1969, American astronauts Neil Armstrong and Buzz Aldrin landed the lunar module Eagle on the Sea of Tranquility, while Michael Collins orbited above. The mission fulfilled a national goal set eight years earlier and became one of the defining moments of the 20th century.

Background

The Moon landing grew out of the Space Race, the Cold War competition between the United States and the Soviet Union. The Soviet Union launched the first artificial satellite, Sputnik 1, in 1957, and in April 1961 Yuri Gagarin became the first person to orbit the Earth. These early Soviet successes alarmed American leaders, who saw space achievements as a measure of technological and political strength.

On 25 May 1961, President John F. Kennedy told the United States Congress that the nation should commit itself to landing a man on the Moon and returning him safely to Earth before the end of the decade. NASA’s Apollo programme was built to meet that goal. At its peak in the mid-1960s it employed roughly 400,000 people across government, industry and universities, and it consumed a significant share of the federal budget.

NASA approached the Moon in stages. The one-person Mercury flights showed that Americans could survive in orbit. The two-person Gemini missions of 1965–1966 then practised the skills a lunar mission would need: long-duration flights, spacewalks, and the rendezvous and docking of two spacecraft in orbit.

Apollo suffered a tragedy in January 1967, when a fire during a launch rehearsal killed the three-man crew of Apollo 1. The spacecraft was extensively redesigned before crews flew again. In December 1968, Apollo 8 became the first crewed mission to orbit the Moon, and in 1969 Apollo 9 and Apollo 10 tested the lunar module in Earth orbit and in lunar orbit. Apollo 10 flew to within about 15 kilometres of the surface, a full rehearsal of everything except the landing itself.

The crew and spacecraft

Apollo 11’s commander was Neil Armstrong, a former naval aviator and test pilot. Edwin “Buzz” Aldrin, an Air Force pilot with a doctorate in astronautics, was the lunar module pilot. Michael Collins, also an Air Force test pilot, was the command module pilot.

The spacecraft had two main parts. The command module Columbia, attached to a service module, would carry the crew to lunar orbit and back to Earth. The lunar module Eagle was designed to take two astronauts down to the surface and return them to orbit. The whole stack was launched by a Saturn V, the most powerful rocket that had flown at that time. Standing about 110 metres tall, it was designed by a team led by Wernher von Braun at NASA’s Marshall Space Flight Center.

The crew was assigned through NASA’s normal rotation of flight crews, and Apollo 11 became the first landing attempt because the test flights before it succeeded. All three were veterans of the Gemini programme. Armstrong, as commander, would be first out of the lunar module.

The mission

Launch and journey

Apollo 11 lifted off from Launch Complex 39A at Kennedy Space Center, Florida, at 9:32 a.m. Eastern Daylight Time on 16 July 1969. Large crowds watched from nearby beaches and roads. After about two and a half hours in Earth orbit, the third stage of the Saturn V fired again to send the spacecraft towards the Moon. The crew then turned Columbia around and docked with Eagle, pulling it free of the spent rocket stage. After about three days the spacecraft entered orbit around the Moon on 19 July.

The landing

On 20 July, Armstrong and Aldrin separated Eagle from Columbia and began their descent. During the final approach the guidance computer raised several program alarms, numbered 1202 and 1201, which meant it was overloaded with tasks. Flight controllers in Houston quickly judged that it was safe to continue, because the software, developed at the MIT Instrumentation Laboratory, was designed to drop low-priority work and keep the essential guidance running.

Armstrong then saw that the planned landing area was covered in boulders near a large crater. He took manual control and flew on to find a safer spot, landing with very little fuel to spare: estimates of the remaining hover time are usually given as well under a minute.

At 20:17 UTC Armstrong reported to Mission Control in Houston: “Houston, Tranquility Base here. The Eagle has landed.” Several hours later, at 02:56 UTC on 21 July (late evening of 20 July in the United States), he climbed down the ladder and stepped onto the surface, saying: “That’s one small step for man, one giant leap for mankind.” Aldrin joined him about 20 minutes later.

On the surface

The two astronauts spent about two and a half hours outside. They tested how to move in the low gravity, which is about one-sixth of Earth’s, and found that a loping, bounding gait worked well. They collected about 21.5 kilograms (47.5 pounds) of lunar rock and soil, unrolled a sheet of foil to catch particles of the solar wind, and set up a seismometer to detect moonquakes and a laser reflector that scientists still use to measure the distance between the Earth and the Moon. They also planted a United States flag and spoke by radio-telephone with President Richard Nixon.

They left behind a plaque on Eagle’s descent stage, signed by the crew and the president, which reads in part: “Here men from the planet Earth first set foot upon the Moon, July 1969, A.D. We came in peace for all mankind.” The television broadcast of the moonwalk was watched by an estimated 600 million people around the world, one of the largest audiences in history up to that time.

Return to Earth and legacy

After about 21.5 hours on the Moon, Eagle’s ascent stage lifted off on 21 July and docked with Columbia, where Collins had been orbiting alone. The crew then fired the service module engine to leave lunar orbit and head home.

Columbia splashed down in the Pacific Ocean on 24 July 1969 and the astronauts were recovered by the aircraft carrier USS Hornet. Because scientists could not yet rule out lunar germs, the crew spent about three weeks in quarantine before being celebrated with parades in New York and around the world. They then made a goodwill tour of more than 20 countries in the autumn of 1969.

The rocks and soil they brought back were studied by scientists in the United States and many other countries. They showed that the Sea of Tranquility is made of volcanic basalt more than three billion years old, and they helped build the modern picture of the Moon’s violent early history. Five more Apollo crews reached the surface by the end of 1972; only Apollo 13, crippled by an explosion in 1970, failed to land.

None of the Apollo 11 astronauts flew in space again. Armstrong became a university professor in Ohio, Aldrin wrote and spoke widely about space exploration, and Collins became director of the Smithsonian’s National Air and Space Museum in Washington, which now displays Columbia.

Myths and facts

Myth: the landing was faked. Polls have long found a minority of people who believe this, but the evidence for the landings is overwhelming. It includes lunar samples unlike any Earth rock, equipment left on the surface that scientists still use, tracking by independent observers including the Soviet Union, and modern orbital photographs of the landing sites.

Myth: the flag “waving” proves it was filmed on Earth. The flag was held out by a horizontal rod along its top edge. It moved only while the astronauts were twisting the pole into the ground; with no air to slow it, the motion took a little while to die away.

Myth: Apollo 11 was the first spacecraft to reach the Moon. Soviet and American probes had already hit, orbited and soft-landed on the Moon, and Apollo 8 had carried astronauts around it. Apollo 11 was the first mission to land people there.

By the numbers

Timeline

• 1961, 25 May: President Kennedy sets the goal of a crewed Moon landing within the decade.
• 1967, 27 January: The Apollo 1 fire kills three astronauts during a ground test.
• 1968, December: Apollo 8 makes the first crewed flight around the Moon.
• 1969, 16 July: Apollo 11 launches from Kennedy Space Center.
• 1969, 20 July: Eagle lands on the Sea of Tranquility.
• 1969, 21 July: Armstrong and Aldrin walk on the Moon, then lift off to rejoin Columbia.
• 1969, 24 July: The crew splashes down safely in the Pacific Ocean.
• 1972, December: Apollo 17, the last crewed Moon landing to date, returns to Earth.

Why it matters

Apollo 11 showed that human beings could travel to and work on another world, and it effectively ended the race to the Moon. Twelve astronauts walked on the Moon in six landings between 1969 and 1972. Coming just 66 years after the Wright brothers’ first flight, the landing remains a symbol of scientific ambition and of what large-scale cooperation can achieve.