Sputnik 1 (; "Satellite-1", or ПС-1 ["PS-1", i.e. "Elementary Satellite 1"]) was the first
artificial Earth satellite. The
Soviet Union launched it into an elliptical
low Earth orbit on 4 October 1957. It was a diameter polished metal sphere, with four external radio antennae to broadcast radio pulses. It was visible all around the Earth and its radio pulses were detectable. This surprise success precipitated the American
Sputnik crisis and triggered the
Space Race, a part of the larger
Cold War. The launch ushered in new political, military, technological, and scientific developments.