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Satellite phone

technology Maturity 5-7 Next article →

A satellite phone is a special mobile phone. It connects to the phone network using orbiting satellites. Most phones use towers on the ground to work. These ground towers are called terrestrial cell sites. Satellite phones work when those towers are not available. They can help in remote places or after disasters. You might use one on a ship or a plane.

Satellite telephony RD-TD diagram
Satellite telephony RD-TD diagram

How these phones work depends on the satellite's path. Some use geostationary orbit, or GEO. These satellites stay in a fixed spot in the sky. They can cover huge areas of the Earth. However, the signal travels a long way. This can cause a tiny delay called latency. Other systems use low Earth orbit, or LEO. These satellites move very fast around the planet. They orbit Earth every 70 to 100 minutes.

Satellite telephony RD-TD diagram
Satellite telephony RD-TD diagram

Because LEO satellites move so fast, we need many of them. This group of satellites is called a constellation. A satellite might only be visible for a few minutes. Iridium uses 66 satellites near the poles to provide coverage. Globalstar uses 48 active satellites for most land areas. Both of these systems started in the late 1990s. They both faced bankruptcy before being restructured later.

Iridium Satellite Phone
Iridium Satellite Phone

People have used satellites for talking for a long time. The first voice signals went through a satellite in 1958. This was the experimental SCORE satellite. In 1976, a system called MARISAT became the first dedicated mobile satellite. Later, the Inmarsat organization was founded in 1979. In 1963, Prime Minister Abubakar Tafawa Balewa used a SYNCOM satellite. He spoke with President John F. Kennedy using that tool.

USNS Kingsport SYNCOM Call Kennedy-Balewa July 1963
USNS Kingsport SYNCOM Call Kennedy-Balewa July 1963

Today, satellite technology is part of our everyday lives. Some new smartphones can talk to satellites for emergencies. The iPhone 14 added emergency messaging in 2022. The iPhone 15 added roadside assistance in 2023. Other phones like the Huawei Mate 50 also have this. Some phones even use a special antenna that pulls out. Using these services can be expensive for people. This is because launching and keeping satellites is a hard job.

Globalstar GSP-1600 satellite phone
Globalstar GSP-1600 satellite phone
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🖼️ Images & Media (4)
File:Iridium Satellite Phone.jpg
Iridium Satellite Phone.jpg
File:Globalstar GSP-1600 satellite phone.jpg
Globalstar GSP-1600 satellite phone.jpg
File:USNS Kingsport SYNCOM Call Kennedy-Balewa July 1963.png
USNS Kingsport SYNCOM Call Kennedy-Balewa...
File:Satellite telephony RD-TD diagram.png
Satellite telephony RD-TD diagram.png
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