Galileo Satellite Navigation (EU / ESA)
Europe's Galileo is the world's most precise satellite navigation system, serving over five billion smartphone users and helping rescues (ESA).
Image: NASA (iss074e0149572, city lights trace river valleys in Romania).
Last reviewed: 3 sources cited
Explain Like I'm 10
- Galileo is a group of satellites that tells your phone exactly where it is.
- Each satellite has very accurate atomic clocks.
- Galileo satellites can also hear emergency beacons and pass the alert to rescuers.
The Five W's of Galileo
Who
The European Union owns and funds Galileo through the European Commission. ESA designs and builds it, and EUSPA runs the service.
What
A constellation designed for 30 satellites, 3 of them spares. Each carries atomic clocks and a search-and-rescue antenna.
Source: ESA, Galileo satellites
When
Open Service began in 2016. Satellites SAT 33 and SAT 34 entered service in 2026, and four first-generation satellites remain to launch.
Where
In medium Earth The curved path an object takes as it travels around a planet, moon or star, like a satellite circling Earth. Glossary, at 23,222 km.
Why
Precise positioning and timing matter for rail, shipping, farming, finance and rescue operations (ESA).
Connected Solutions
- SARSAT The international distress-beacon system that Galileo's rescue antennas feed into.
Impact Statement
Agency solution · active
Galileo serves over five billion smartphone users around the globe, and all smartphones sold in the EU single market are guaranteed Galileo-enabled (ESA).
Source: ESA, Two new Galileo satellites enter service
For Further Information: ESA, Two new Galileo satellites enter service
Each Galileo satellite's hydrogen maser clock keeps time to within 0.45 billionths of a second over 12 hours (ESA).
How This Saves People & the Planet
For People
Galileo's search-and-rescue antenna picks up distress signals from beacons and sends them on to local rescue services (ESA).
Source: ESA, Galileo satellites
For Nature
Precise positioning supports farming, one of the fields where ESA says Galileo is making a difference (ESA).
Learn More About Galileo
Want to go deeper? ESA has the full Galileo story.
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Links go straight to the organization. Saving Planets doesn't receive any of the money.