History changed on 4 October 1957, when the Soviet Union successfully launched Sputnik I. The world's first artificial satellite was about the size of a beach ball (58 cm across), weighed only 83.6 kg and took about 98 minutes to orbit the Earth on its elliptical path. That launch ushered in new political, military, technological and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the US-USSR space race.
This audio file is a recording of the telemetry signals transmitted by Sputnik from orbit - the first artificial signals ever delivered from space. Text credit: NASA (https://history.nasa.gov/sputnik/)
Image, audio credit: NASA CC BY-NC-SA
