Galileo ‘daughter mission’ name revealed: Celeste
Following the announcement of the upcoming launch of LEO-PNT’s first satellites, ESA has now unveiled the name of the mission. Celeste, as it has been officially designated, will test the potential of a new, low Earth orbit layer of satellites to enhance Galileo’s resilience and complement its capabilities.
Over the past three decades, European satellite navigation systems have become integral to our society. Galileo and EGNOS are a huge success today, powering everything from smartphones to critical infrastructure. Now, ESA’s Low Earth Orbit Positioning Navigation Timing (LEO-PNT) mission, Celeste, is working to ensure these systems remain robust, secure and available.
Galileo and Celeste, a story of support and resilience
The name Celeste is a symbolic wink to the scientific past on which satellite navigation is founded. Maria Celeste was Galileo Galilei’s daughter, and the two shared a strong emotional and intellectual bond. She also honoured her father’s love for astronomy. Based on historic letters between father and daughter, we know how much Galileo valued his daughter and trusted her judgement.
Now, Celeste becomes the name of ESA’s LEO-PNT mission that will ‘mediate’ between Galileo and the rest of the world. The mission aims to demonstrate in orbit new capabilities for added resilience, representing a new dimension of strength for Europe’s navigation capabilities.
Celeste features a constellation of ten satellites that will fly close to Earth to test innovative signals across various frequency bands. The first two Celeste satellites, built in parallel by GMV and Thales Alenia Space, are set to launch in the coming months.
Celeste joins Europe’s satellite navigation family with another symbolic name that links the past to the present, and the future. Europe’s global satellite navigation system is named Galileo, in honour of the famous Italian scientist Galileo Galilei and in recognition of his pioneering role in astronomy, physics and time measurement, all foundational to precise satellite navigation.
The demonstrator satellites for Galileo, launched in 2005 and 2008, were called GIOVE, after the Italian word for Jupiter. This name also paid tribute to Galileo’s achievements in discovering the planet’s four largest Moons which were used to determine longitude from anywhere on Earth.
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About Celeste (LEO-PNT)
The Celeste mission is ESA's initiative for LEO-PNT (Low Earth Orbit Positioning Navigation and Timing) and is currently in its in-orbit demonstration phase. This first phase features a demonstration constellation of 11 satellites that will fly in low Earth orbit to test innovative signals across various frequency bands. Its goal is to advance satellite navigation concepts for resilient positioning and timing services.
The Celeste in-orbit demonstration phase was approved at ESA’s Council at Ministerial Level of 2022. The fleet is being developed through two parallel contracts respectively led by GMV in Spain with OHB in Germany as core partner, and by Thales Alenia France as prime and Thales Alenia Italy as space segment responsible, and involving over 50 entities from more than 14 countries.
Celeste was further supported in ESA’s Council at Ministerial Level of 2025 (CM25), towards the implementation of the next phase: the LEO-PNT In-Orbit Preparatory phase.
Celeste also contributes to one of the three core pillars of ESA’s new European Resilience from Space (ERS) initiative, endorsed at CM25. ERS addresses critical security and resilience needs for Member States while laying the groundwork for future European strategic space capabilities.
For more information, visit www.esa.int/Celeste/.