Satellite Phones

Satellite Telephones have been around for over 20 years however they haven't been available to non-military customers until very recently. The primary advantages of satellite communications is the ability to communicate from anywhere in the world, instead of worrying about being in or near a compatible cellular network. The disadvantages are equipment size and cost and communication latency or delays.

For a satellite communications network to work they need to have multiple satellite in geosynchronous earth orbit. This means the satellites remain over a fixed geographic place over the earth and keep that position. The amount of satellites required for world wide coverage depends on the altitude of the satellite above the earth. The higher the orbit the lower the number satellites required. However the higher the satellites orbit the longer the communication latency. This means it could take several seconds for what you say to reach the person on the other line and vice-versa. The more satellites involved the higher the cost to develop, maintain, and run the network. So a trade off exists to achieve the best balance of cost versus development time.

One of the most ambitious plans to date is the Iridium network. The Iridium network was designed to operate with 66 geosynchronous satellites in orbit, (and 8 backup satellites). The plan was begun in 1990 and started offering service on a limited basis in 1998. With this large amount of satellites they were able to reduce the latency factor, and keep the size of the phones to a size slightly larger than standard sized cellular phones. The expense however was too much for all but the most specialized business to afford and Iridium filed for bankruptcy in 1999. In 2001 they were purchased and began to operate under the newly formed corporation Iridium Satellite LLC.

Some companies are testing alternatives to satellite communications using high altitude long operation planes (HALO). Pilots will take planes and fly them in circles over specific geographic regions duplicating a satellite network, without the cost of putting a satellite into orbit and nearly eliminating the communication delay.