The first artificial satellite launched into space was Sputnik I. The Soviet Union launched it on October 4, 1957, placing it into an elliptical low Earth orbit and beginning the Space Age.
Sputnik I was a polished metal sphere about 58 centimeters in diameter, equipped with four whip antennas that transmitted simple radio beeps. Those signals could be detected by radio operators around the world, making the satellite's progress surprisingly easy to follow.
The launch was a major technological and political shock to the United States. It helped trigger the Sputnik crisis, accelerated the American space program, and intensified the Cold War Space Race. The satellite's launch vehicle was based on the Soviet R-7 rocket, designed under chief engineer Sergei Korolev.
Sputnik I transmitted for about three weeks before its batteries failed. Atmospheric drag eventually pulled it back to Earth, where it burned up on January 4, 1958. It is sometimes confused with Sputnik II, which carried the dog Laika, but Sputnik I carried instruments and a radio transmitter only.