Launch of Sputnik-1 (1957)
Sputnik 1, "Satellite-1", or "PS-1", was the first artificial Earth satellite. The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957, orbiting for three weeks before its batteries died, then silently for two more months before
1957-10-04 19:00:00 - David Hoffman
It was a 58 cm (23 in) diameter polished metal sphere, with four external radio antennas to broadcast radio pulses. Its radio signal was easily detectable even by radio amateurs and the 65° inclination and duration of its orbit made its flight path cover virtually the entire inhabited Earth.
This surprise success precipitated the American Sputnik crisis and triggered the Space Race, a part of the Cold War.
The launch was the beginning of a new era of political, military, technological, and scientific developments.