Sputnik 1 became the first human-made object to orbit Earth in 1957.
The Soviet Union launched Sputnik 1 on 4 October 1957 from the Baikonur Cosmodrome. The polished spherical satellite had four whip-like antennas and transmitted simple radio signals that could be detected around the world. Its launch marked the beginning of the Space Age and intensified the space race between the Soviet Union and the United States.
Sputnik 1 orbited Earth at an altitude of roughly 215 to 939 kilometres. It completed an orbit in about 96 minutes and remained in space for approximately three months before re-entering the atmosphere on 4 January 1958.
Sputnik 1 carried no human passengers. Sputnik 2 followed in November 1957 and carried the dog Laika, while Vostok 1 carried Yuri Gagarin on the first human spaceflight in 1961. The American response included Explorer 1, launched in January 1958.