7. Satellite phones

These work in a similar way to the mobile in that they both use radio technology. But a satellite phone makes contact with a Low Earth Orbit (LEO) satellite as a base station rather than a terrestrial mast.

LEO satellites move around the Earth very rapidly, so a number of them are needed to have one in constant view. As one drops below the horizon, then next one is appearing over the horizon.

Effectively you are standing still and the 'cell' is moving around.

The clip below explains how they work in more detail