Unlike their terrestrial counterparts, satellite phone networks allow seamless communication
without wires and without the need of cell phone towers.
This provides several advantages, the most important being the ability to function regardless of any adverse conditions on the ground. However all satellite networks do not provide the same functionality and coverage. In fact a significant consideration when selecting a satellite phone solution is ascertaining the type of service and service area of your need and/or application.
Satellite systems fall under 2 categories:
LEO (Low Earth Orbit)
Geostationary (Fixed)
LEO (Low Earth Orbit) = Reliable
Iridium is an excellent example of LEO satellite phone networks. LEO satellites are small, mobile, and as their name suggests they are in a lower earth orbit. The most redeeming feature of these networks is the easy to get signal allowing for high voice quality and while data is available it is usually at a very slow speed between 2.4 and 9.6kbps. Network reliability is superior due to the fact that there are more satellites that make up the network thus reducing any risk of a single point failure. Using the Iridium network as an example, there are over sixty (60) satellites linked together in orbit and at any one time there are three (3) of those satellites in your horizons to guarantee you provision of communication.
Geostationary = Powerful
Inmarsat is a superior example of a geostationary constellation. Geostationary satellites are big powerful satellites in a high-earth orbit and a single satellite will beam a signal over a large portion of the earths surface. Geostationary networks are capable of providing high quality voice and data services allowing users the luxury of 21st century communications regardless of where their travels may take them. While reliable a geostationary network is typically made up of only 3 or 4 satellites so when there is maintenance, planned or otherwise, if you lose just one satellite you may lose service over an entire continent and/or ocean.
Solutions
For mission critical requirements your satellite phone solution can often involve the layering of products to ensure you always have connectivity. When a business need or application requires high-speed data a Geostationary option would be to the fore however it could be wise to have an alternate voice option on a LEO network to ensure some form of redundancy.