Apollo program
NASA’s human spaceflight program, active from 1961 to 1972, landed the first people on the Moon and returned them safely to Earth.
Apollo 1: The planned first crewed Apollo mission, whose cabin fire killed astronauts Gus Grissom, Ed White, and Roger B. Chaffee during a 1967 test. The fatal ground test prompted major spacecraft and safety redesigns before crewed Apollo flights resumed.
Saturn V: A multistage launch vehicle that carried Apollo crews and spacecraft toward the Moon. Its heavy-lift capability launched the complete Apollo lunar mission stack.
Space Race: The Cold War competition between the United States and the Soviet Union in space exploration and technology. Apollo became the United States’ answer to early Soviet achievements in space.
Lunar sample return: The collection and transport of material from the Moon to Earth for analysis. Apollo astronauts returned rock and soil samples that transformed knowledge of lunar history.
Project Gemini: NASA’s crewed spaceflight program between Mercury and Apollo, focused on techniques for lunar missions. Gemini practiced rendezvous, docking, and long-duration flight needed for Apollo.
Apollo 7: The first crewed Apollo mission, which tested the command and service module in Earth orbit in 1968. Its successful flight demonstrated that redesigned Apollo hardware was ready for crewed operations.
Apollo command and service module: The crewed spacecraft comprising a reentry command module and a service module for propulsion and support. It carried astronauts to lunar orbit and returned them to Earth.
Sputnik 1: The first artificial Earth satellite, launched by the Soviet Union in 1957. Its launch intensified American concern about Soviet technological and strategic leadership.
Apollo Lunar Surface Experiments Package: A set of scientific instruments deployed at several Apollo landing sites to study the lunar environment. Its instruments continued transmitting measurements after astronauts departed.
Space Shuttle program: NASA’s reusable crewed spacecraft program, which operated in low Earth orbit from 1981 to 2011. Unlike Apollo’s lunar expeditions, the Shuttle focused on repeated access to Earth orbit.