How it works
Satellites in low Earth orbit carry equipment that behaves like a cell tower in the sky. A phone sends its normal signal, the satellite picks it up and relays it to a ground station, which connects it to the usual network. Standards bodies have added support for these “non-terrestrial networks” to the mobile standards, starting with 3GPP Release 17, so phones and satellites can speak the same language.
What it can and cannot do today
Early services focus on text messages, emergency alerts and basic data, because a phone has a tiny antenna and the satellite is hundreds of kilometres away. Video and fast browsing from space to an unmodified phone are much harder, and speeds are shared among everyone under a satellite’s beam.
Why it matters
Large parts of the world’s land and almost all of its oceans have no mobile coverage. Satellite links can fill those gaps for travellers, farms, ships and emergency services, working alongside towers instead of replacing them.
Where it is used
- Emergencies Sending a message from a place with no coverage.
- Travellers, hikers and sailors A basic link where there are no towers.
- Remote sites such as farms and mines Alerts and simple data when the nearest tower is far away.
Direct-to-device compared with satellite phones and mobile towers
A satellite phone is a dedicated device that works almost anywhere but costs more and is bulkier. A mobile tower gives the best speed and price wherever there is one.
Direct-to-device lets an ordinary phone reach a satellite for basic services when there is no tower, with limits on speed and capacity.
Key terms
- Low Earth orbit
- An orbit from a few hundred up to about two thousand kilometres above the ground.
- Non-terrestrial network
- A mobile network that uses satellites or high-altitude platforms.
- Beam
- The area on the ground that one satellite antenna serves at a time.
- Ground station
- The station on Earth that links a satellite to the wider network.
Common questions
Does satellite-to-phone replace mobile towers?
- No. Towers are far faster and cheaper where people live. Satellites are meant to cover the gaps.
Do I need a special phone?
- For basic messaging, many recent phones work, depending on the model and the mobile operator. Higher speeds may need newer hardware.
How is this different from a satellite phone?
- A satellite phone is a dedicated device with a larger antenna. Direct-to-device aims to use the phone you already own.
Sources and further reading
Independent pages we checked while writing this guide. They are not Reinnder products, and Reinnder is not affiliated with them.
Reinnder’s angle
How Reinnder looks at satellite straight to your phone
Reinnder Networks & Space is the planned home for connectivity work in places where no network reaches.
This guide explains the technology in general terms. It is not advice, and it does not describe a Reinnder product on sale.