Post-war advances in rocket technology and Cold War strategic rivalry pushed space programmes into a position of political priority. After the Soviet Union orbited Sputnik in 1957 and launched Yuri Gagarin into space in 1961, US President John F. Kennedy responded in the spring of 1961 by declaring the goal of "landing a man on the Moon before the decade is out."

The project was pursued through an enormous eight-year engineering effort: the work of some 400,000 people, navigation software pushing the limits of contemporary computing, and the three-stage Saturn V rocket. Apollo 11 launched on 16 July 1969. Michael Collins remained in lunar orbit in the command module; the lunar module "Eagle," carrying Armstrong and Aldrin, touched down in the Sea of Tranquility on 20 July.

The astronauts spent about two and a half hours outside on the surface. They deployed a seismometer, a laser retroreflector, and a solar-wind collector, and gathered 21.5 kg of lunar rock samples. Six further successful landings followed over the next three and a half years.

Scientifically, Apollo 11 returned data that supports the giant-impact hypothesis of the Moon's formation. Technologically, it left lasting marks on the integrated circuit, real-time computer control, and large-scale systems engineering. Symbolically, it was the threshold at which humanity took its first step beyond its own planet.