A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites. They provide similar functionality to terrestrial mobile telephones; voice, short messaging service and low-bandwidth internet access are supported through most systems.Depending on the architecture of a particular system, coverage may include the entire Earth, or only specific regions.The mobile equipment, also known as a terminal, varies widely. Early satellite phone handsets had a size and weight comparable to that of a late-1980s or early-1990s mobile phone, but usually with a large retractable antenna. More recent satellite phones are similar in size to a regular mobile phone while some prototype satellite phones have no distinguishable difference from an ordinary smartphone. Satphones are popular on expeditions into remote areas where terrestrial cellular service is unavailable.A fixed installation, such as one used aboard a ship, may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites. Smaller installations using VoIP over a two-way satellite broadband service such as BGAN or VSAT bring the costs within the reach of leisure vessel owners. Internet service satellite phones have notoriously poor reception indoors, though it may be possible to get a consistent signal near a window or in the top floor of a building if the roof is sufficiently thin. The phones have connectors for external antennas that are often installed in vehicles and buildings. The systems also allow for the use of repeaters, much like terrestrial mobile phone systems.
While it is possible to obtain used handsets for the Thuraya, Iridium, and Globalstar networks for approximately US$200, the newest handsets are quite expensive. The Iridium 9505A, released in 2001, sold in March 2010 for over $1,000 USD new. Since satellite phones are purpose-built for one particular network and cannot be switched to other networks, the price of handsets varies with network performance. If a satellite phone provider encounters trouble with its network, handset prices will fall, then increase once new satellites are launched. Similarly, handset prices will increase when calling rates are reduced.Among the most expensive satellite phones are BGAN terminals, often costing several thousand US dollars. These phones provide broadband Internet and voice communications. Satellite phones are sometimes subsidised by the provider if one signs a post-paid contract but subsidies are usually only a few hundred US dollars or less. Inmarsat has also introduced a new handheld satellite June-2010 called IsatPhone Pro. It is the least expensive handset and service to date. Since most satellite phones are built under license or the manufacturing of handsets is contracted out to OEMs, operators have a large influence over the selling price. Satellite networks operate under proprietary closed standards, making it difficult for manufacturers to independently make handsets.