Apollo Program

The Apollo Program was NASA’s effort to land people on the Moon and bring them home safely. Between 1961 and 1972 it did exactly that, putting 12 astronauts on the lunar surface and becoming the only program ever to land humans on another world.

Quick facts

• Run by: NASA, the United States space agency, from 1961 to 1972.
• Goal: Meet President John F. Kennedy’s 1961 challenge to land a person on the Moon and return them safely to Earth before the decade ended.
• First landing: Apollo 11, July 20, 1969, when Neil Armstrong became the first human to walk on another world.
• Final landing: Apollo 17, December 1972.
• Crewed missions: 11 flew; 6 landed humans on the Moon (Apollo 11, 12, 14, 15, 16, and 17).
• People: 24 astronauts traveled to the Moon (3 of them twice); 12 walked on the surface.
• Samples returned: about 842 pounds (382 kg) of Moon rock and soil.
• Cost: about $25.4 billion in then-year dollars (roughly $257 billion in 2020 dollars).

How a Moon mission worked

Each landing began with a launch on the Saturn V, a three-stage rocket about 363 feet (111 m) tall with roughly 7.5 million pounds of liftoff thrust. A “stage” is a self-contained rocket section that fires, then drops away once empty, so the remaining vehicle is lighter. The three stages fired in sequence to reach Earth orbit, then the top stage reignited for “translunar injection,” the push that sent the spacecraft toward the Moon.

The Apollo spacecraft had three parts. The cone-shaped Command Module was the crew cabin and the only piece that came home. The Service Module held the main engine, fuel, oxygen, and power. The spider-like Lunar Module did the actual landing. After coasting to the Moon and entering orbit around it, two astronauts moved into the Lunar Module, undocked, and rode it down to the surface while a third astronaut stayed in the orbiting Command Module.

To leave, the Lunar Module split in two: its upper “ascent stage” blasted off the lower half, which served as a launch pad, and rejoined the Command Module in orbit. The crew transferred back, the Service Module engine fired for the trip home, and just before reentry that module was cast off too. Only the heat-shielded Command Module reentered Earth’s atmosphere, splashing down in the ocean under parachutes.

This step-by-step approach, called Lunar Orbit Rendezvous, left part of the spacecraft in lunar orbit and landed only the lightweight Lunar Module. NASA chose it over heavier plans because it cut the mass a single Saturn V had to lift, even though it required risky dockings far from Earth.

Why it matters

Apollo is the only program ever to land humans on another world, making it a defining achievement of the 20th century and the high point of the US-Soviet Space Race. It proved that people could travel to deep space, work there, and return safely, and it drove major advances in rocketry, computing, materials, life support, and systems engineering. The returned lunar samples transformed understanding of the Moon’s origin, composition, and geologic history and still support research today. The Saturn V remains the benchmark heavy-lift rocket against which vehicles like SLS and Starship are measured, and Apollo’s hardware lineage and navigation techniques directly inform today’s Artemis effort to return to the Moon.

Notable missions and hardware

• Apollo 8 (December 1968): first crewed mission to leave Earth orbit and circle the Moon (10 orbits); its crew took the famous “Earthrise” photograph, which reshaped how people saw their home planet and helped galvanize the modern environmental movement.
• Apollo 11 (July 1969): the first crewed Moon landing; Neil Armstrong and Buzz Aldrin walked on the Sea of Tranquility while Michael Collins orbited above.
• Apollo 13 (April 1970): an oxygen tank exploded on the way to the Moon, and the crew survived by using the Lunar Module as a “lifeboat,” a landmark of crisis engineering.
• Apollo 17 (December 1972): the final and longest landing, carrying NASA’s first scientist-astronaut, geologist Harrison Schmitt, alongside commander Eugene Cernan, the last person to walk on the Moon.
• Saturn V: the super heavy-lift rocket behind every crewed lunar mission and still the most powerful launch vehicle ever to fly operationally.

The program’s worst tragedy was the Apollo 1 fire of January 27, 1967, when a cabin fire during a ground test killed astronauts Gus Grissom, Ed White, and Roger Chaffee, forcing a major redesign of the Command Module. Later missions carried the battery-powered Lunar Roving Vehicle to extend exploration, while planned flights Apollo 18, 19, and 20 were cancelled due to budget cuts and waning public interest.