The space age is 60 years old today.
October 4th 1957 the Soviet Union launched the first artificial satellite to orbit the Earth : Sputnik, sending it characteristic “beep-beep-beep” signal to Earth on 20 and 40 MHz.
The satellite weighed about 83 kilograms and sent the beeps till the battery ran out.
Here is a sample of how the signal sounded :
or this one : http://www.astrosurf.com/luxorion/Documents/sat-sputnik.wav