Apollo 11

Apollo 11 was the first spaceflight to land humans on the Moon, conducted by NASA from July 16 to 24, 1969. Commander Neil Armstrong and Lunar Module Pilot Edwin "Buzz" Aldrin landed the Lunar Module Eagle on July 20 at 20:17 UTC, and Armstrong became the first person to step onto the surface about six hours later, at 02:56 UTC 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 47.5 pounds (21.5 kg) of lunar material to bring back to Earth 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 13:32 UTC (9:32 am EDT, local time). It was the fifth crewed mission of the Apollo program. The Apollo spacecraft consisted of three parts: the command module (CM), which housed the three astronauts and was the only part to return to Earth; the service module (SM), which provided propulsion, electrical power, oxygen, and water to the command module; and the Lunar Module (LM), 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 from it 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 Eagle's ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned Eagle before they performed 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 16:35:35 UTC 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 [a] 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".

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 sparked the Sputnik crisis and ignited the Space Race, as both superpowers sought to demonstrate their superiority in spaceflight. President Dwight D. Eisenhower responded to the challenge posed by Sputnik by creating the National Aeronautics and Space Administration (NASA), 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 the U.S. and Soviet Union would be starting from a position of equality. 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:

I believe that this nation should commit itself to achieving the goal, before this decade [1960s] 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. We propose to accelerate the development of the appropriate lunar space craft. We propose to develop alternate liquid and solid fuel boosters, much larger than any now being developed, until certain which is superior. We propose additional funds for other engine development and for unmanned explorations—explorations which are particularly important for one purpose which this nation will never overlook: the survival of the man who first makes this daring flight. But in a very real sense, it will not be one man going to the Moon—if we make this judgment affirmatively, it will be an entire nation. For all of us must work to put him there.