The Space Race was a mid-to-late twentieth century competition between the Soviet Union (USSR) and the United States (USA) for supremacy in outer space exploration. The term refers to a specific period in human history, 1957-1975, and does not include subsequent efforts by these or other nations to explore space. The race was both ideological and technological, and it involved pioneering efforts to launch artificial satellites, sub-orbital and orbital human spaceflight around the earth, and piloted voyages to the Moon.

The Space Race had its origins in the missile-based arms race that occurred just after the end of the Second World War, with both the Soviet Union and the United States capturing advanced German rocket technology and personnel. It was motivated by the Cold War desire to display scientific and technological superiority, which translated into military strength. Between 1957 and 1975, the ideological and technological rivalry between the two nations became focused on space exploration. The Space Race effectively began with the Soviet launch of the Sputnik 1 artificial satellite on 4 October 1957, and it concluded with the co-operative Apollo-Soyuz Test Project human spaceflight mission in July 1975, which came to symbolize détente between the USA and USSR.

The Space Race sparked unprecedented increases in spending on education and pure research, which accelerated scientific advancements and led to beneficial spin-off technoligies. An unintended consequence was that the Space Race became partially responsible for the birth of the environmental movement; for the first time, access to space enabled humans to see their home-world as it really appears-–color pictures from space showed a fragile blue planet bordered by the blackness of space.