Apollo program (1961–1972)
The U.S public's perception of the Soviet lead in the space race (by putting the first man into space) motivated President John F. Kennedy to ask the Congress on May 25, 1961,
to commit the federal government to a program to land a man on the Moon by the end of the 1960s, which effectively launched the Apollo program.
Apollo was one of the most expensive American scientific programs ever. It cost more than $20 billion in 1960s dollars or an estimated $223 billion in present-day US dollars.
(In comparison, the Manhattan Project cost roughly $28.4 billion, accounting for inflation.)
It used the Saturn rockets as launch vehicles, which were far bigger than the rockets built for previous projects.
The spacecraft was also bigger; it had two main parts, the combined command and service module (CSM) and the Apollo Lunar Module (LM).
The LM was to be left on the Moon and only the command module (CM) containing the three astronauts would eventually return to Earth.
The second crewed mission, Apollo 8, brought astronauts for the first time in a flight around the Moon in December 1968.
Shortly before, the Soviets had sent an uncrewed spacecraft around the Moon.
On the next two missions docking maneuvers that were needed for the Moon landing were practiced and then finally the Moon landing was made on the Apollo 11 mission in July 1969.
The first person to walk on the Moon was Neil Armstrong, who was followed 19 minutes later by Buzz Aldrin, while Michael Collins orbited above.
Five subsequent Apollo missions also landed astronauts on the Moon, the last in December 1972.
Throughout these six Apollo spaceflights, twelve men walked on the Moon. These missions returned a wealth of scientific data and 381.7 kilograms (842 lb) of lunar samples.
Topics covered by experiments performed included soil mechanics, meteoroids, seismology, heat flow, lunar ranging, magnetic fields, and solar wind.
The Moon landing marked the end of the space race; and as a gesture, Armstrong mentioned mankind when he stepped down on the Moon.
Apollo set major milestones in human spaceflight. It stands alone in sending crewed missions beyond low Earth orbit, and landing humans on another celestial body.
Apollo 8 was the first crewed spacecraft to orbit another celestial body, while Apollo 17 marked the last moonwalk and the last crewed mission beyond low Earth orbit.
The program spurred advances in many areas of technology peripheral to rocketry and crewed spaceflight, including avionics, telecommunications, and computers.
Apollo sparked interest in many fields of engineering and left many physical facilities and machines developed for the program as landmarks.
Many objects and artifacts from the program are on display at various locations throughout the world, notably at the Smithsonian's Air and Space Museums.