The BBC has published directions for building your own history-making satellite:
In simple terms, the Sputnik satellite was a metal sphere almost 2ft (61cm) in diameter, containing a radio transmitter. It also had a battery; equipment to measure temperature; barometric and temperature activated switches; and a fan to stop it getting too hot.
It sent its famous “beep beep” radio signals to earth, altering the transmission to indicate changes in temperature or a sudden drop in pressure caused by a puncture in the satellite’s case. And that’s about it.
You could probably find most of these components lying around your home.
In fact, they’re having a contest for doing just that.
You up for the challenge?