Satellite phone

A mobile telephone that connects to communications satellites instead of relying on nearby terrestrial cellular towers. It can provide service beyond cellular networks, but often requires a clear view of the sky.

Geostationary orbit: An orbit in which a satellite circles Earth above the equator at the same rate Earth rotates, appearing fixed in the sky. Satellites in this orbit can provide broad, stable coverage, but require more power and introduce longer signal delays.
Emergency communication: The exchange of information needed to coordinate assistance during emergencies. Satellite phones can connect rescue teams and people in areas without cellular coverage.
Mobile phone: A portable telephone that communicates through a wireless network. Ordinary mobile phones rely on terrestrial base stations, which satellite phones can reach beyond.
Digital divide: Unequal access to digital technologies and the benefits they provide. Satellite phones can extend basic connectivity to places underserved by terrestrial networks.
Low Earth orbit: An orbit relatively close to Earth, commonly used by satellites that move quickly across the sky. Low-orbit fleets enable satellite phones to connect through moving satellites with shorter signal delays.
Search and rescue: The organized effort to locate and assist people in danger or distress. Remote rescue operations use satellite phones to coordinate when ordinary networks are absent.
Satellite messenger: A portable device that sends short messages through a satellite network, often with location sharing. Satellite messengers usually offer simpler, lower-bandwidth communication than voice-capable satellite phones.
Iridium Communications: A telecommunications company operating a global network of low Earth orbit satellites. Its network is a prominent example of satellite infrastructure designed for worldwide phone service.
Satellite constellation: A group of satellites coordinated to provide coverage or perform a shared task. Global satellite-phone coverage depends on coordinating multiple spacecraft and their links.
Maritime communication: The exchange of information among ships and between ships and shore. Satellite phones maintain voice links far beyond coastal cellular coverage.

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