satellite phone, or satphone, is a mobile phone that communicates directly
with orbiting satellites. Depending on the make of a particular system,
coverage may include the entire planet, or only specific regions. The
mobile equipment, also known as a terminal or earth station, varies widely.
A satellite phone handset has a size and weight comparable to that of
a late 1980s or early 1990s cell phone, but with a large retractable antenna.
These are popular on expeditions into remote areas where any regular cellular
service is unavailable. A fixed installation, such as used on ships, may
include large, rugged, rack-mounted electronics, and a steerable microwave
antenna on the mast that automatically tracks the overhead satellites.