This event marks the launch of the Sputnik 21 satellite on October 4, 1962. The satellite was launched from the Baikonur Cosmodrome in Kazakhstan and was the first artificial satellite to be launched into Earth's orbit. It was part of the Soviet Union's space program and
From Wikipedia
Sputnik 1, often referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries became depleted. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958.