What did the world’s first satellite, Sputnik-1, sound like? I’m skeptical about the authenticity of many alleged audio recordings of Sputnik. This one on NASA’s website has been copied thousands of times, but I do not believe it is actually Sputnik-1:


In fact, pretty much all the facts about this satellite’s signal are incorrect, so I poked around and found some reports by Sergey Korolev. Sputnik-1 transmitted a 1500 Hz tone, alternating between a carrier frequency of 20.005 and 40.002 MHz every 0.4 seconds. The tone did not carry pulse-duration-modulated telemetry, it was just a fixed rate of beeping. However, if the nitrogen pressure inside the spherical hull dropped below a critical level, a relay would change the pulse rate, indicating a probably micrometeorite puncture, which did not occur during the three weeks of transmission.

I was able to find a gramaphone recording made by a ham radio enthusiast in 1957. The sound quality was terrible, but a little filtering brought out the pulse tones very nicely. So here is Sputnik-1: