Who or what was Sputnik?

Sputnik 1 was a radio satellite, which the Soviet Union sent into an orbit 900 km above the Earth in October 1957. The Americans were shocked at this huge technological achievement of the Soviet Union, brought to their notice by the beeps from space-this reaction came to be known as the 'Sputnik Shock'. The Soviet success went even further. In November 1957, a female dog by the name of Laika circled the Earth in Sputnik 2 and became the first living creature to travel in space. However, it died before reaching the Earth. The Americans made their mark in 1958 when they launched a satellite in space, which conducted scientific studies while in orbit.