Satellite phones have some impressive reach, not only in where you can call from but also in how far your signal needs to travel to make that happen. The low earth satellites in the Iridium constellation orbit at a little less than 500 miles above the planet, while the Globalstar birds are at a little less than 900. The geosynchronous satellites of the Inmarsat system, however, are a staggering 22,000 miles, which is quite a long way for your signal to travel — twice!