<P> As well as the now - common cellular phone, there is also the very different approach of connecting directly from the handset to an Earth - orbiting satellite . Such mobile phones can be used in remote areas out of reach of wired networks or where construction of a cellular network is uneconomic . </P> <P> The Inmarsat system is the oldest, originally developed in 1979 for safety of life at sea, and uses a series of satellites in geostationary orbits to cover the majority of the globe . Several smaller operators use the same approach with just one or two satellites to provide a regional service . An alternative approach is to use a series of low Earth orbit satellites much closer to Earth . This is the basis of the Iridium and Globalstar satellite phone services . </P>

When was the first personal cell phone invented