The switchover is happening so that Freeview services can be extended to people who cannot currently get them, including those who receive their signal from a relay transmitter.
It was fifty years since the first live pictures from America were broadcast to Europe, via Telstar 1, the first communications satellite to relay a television signal.
The dish would send the ISP's data up to one of the satellites (in low earth orbits to minimize signal delay), which would then relay the data back down to a backbone access point.