The European Space Agency (ESA) has revealed the name of its new, long-announced mission that will represent the next step in the evolution of satellite navigation on the continent. The mission, officially named Celeste, aims to test and demonstrate the potential of a new layer of satellites in Low Earth Orbit (LEO) to strengthen the resilience and expand the capabilities of the existing Galileo system. This move marks a crucial moment in securing the future of precise positioning, navigation, and timing (PNT) for millions of Europeans and users worldwide.

Over the past three decades, European satellite navigation systems have become an indispensable part of our daily lives. Galileo and EGNOS are a huge success today, powering everything from smartphone applications and car navigation to the management of critical infrastructure such as power grids, financial transactions, and the synchronization of telecommunication systems. It is precisely because of this ubiquitous dependence that ensuring their robustness, security, and constant availability has become a priority of strategic importance. In a world where threats such as jamming and spoofing of signals are increasingly real, the Celeste mission, as part of the broader ESA LEO-PNT program, represents a proactive response to these challenges and a step towards a new generation of navigation technologies.

Galileo and Celeste: A Story of Support and Resilience

The name Celeste carries a deep symbolism, connecting modern technology with the scientific history upon which satellite navigation is based. Namely, Maria Celeste was the daughter of the great Italian scientist Galileo Galilei, and the two shared an exceptionally strong emotional and intellectual bond. Although she lived in a convent, Maria Celeste shared her father's love for astronomy and science. From the surviving letters she sent him, it is clear how much Galileo valued her intelligence, insight, and judgment, often relying on her as his most trusted confidante. Their correspondence reveals a woman of exceptional literacy and understanding of the complex topics her father dealt with.

Now, Celeste becomes the name of a mission that will, symbolically speaking, "mediate" between Galileo and the rest of the world. The goal of the mission is to demonstrate new capabilities in orbit that will bring an additional level of resilience and represent a new dimension of strength for European navigation capacities. Just as Maria Celeste was a support to her father, the Celeste constellation will provide support to the Galileo system, ensuring that its signals remain reliable even in the most challenging conditions.

This choice of name continues a tradition within the European navigation program. The global system itself was named Galileo in honor of the famous scientist, recognizing his pioneering role in astronomy, physics, and timekeeping – disciplines that are the foundation for precise satellite navigation. The demonstration satellites for Galileo, launched in 2005 and 2008, were named GIOVE, which is the Italian word for Jupiter. This name also paid homage to Galileo's discovery of Jupiter's four largest moons, which were used at the time to determine longitude from any point on Earth.

A New Constellation for a New Era of Navigation

The Celeste mission consists of a constellation of ten satellites, with two spares, which will fly in Low Earth Orbit (LEO), at an altitude of a few hundred kilometers, unlike the Galileo satellites which are in Medium Earth Orbit (MEO) at about 23,000 kilometers. This shorter distance from Earth brings key advantages. The signals emitted by the LEO satellites will be significantly stronger, which will improve their ability to penetrate environments where today's GNSS signals are weak or unavailable, such as deep urban canyons, inside buildings, or areas with dense canopies.

In addition to a stronger signal, the faster movement of satellites in LEO will allow for a quicker position lock (Time To First Fix - TTFF) and faster convergence for high-precision services. The system architecture is envisioned as a multi-layered one, where the LEO constellation will work in synergy with existing MEO satellites (Galileo, GPS, etc.), providing additional signals and geometric diversity. This will dramatically increase the overall robustness of the system, making it more resilient to accidental and intentional interference. The first two satellites of the Celeste mission, which are being developed and built in parallel by two European consortia led by GMV and Thales Alenia Space, are scheduled to be launched in the second half of December 2025, from a Rocket Lab Electron launch vehicle from New Zealand.

Pan-European Cooperation for Technological Independence

The Celeste mission, as the demonstration phase of the LEO-PNT program, is a key project within the broader ESA FutureNAV program, which allows the agency to respond to the latest trends and needs in the field of navigation and ensures that Europe remains at the forefront of technological development. The project was approved at the ESA Council at Ministerial level in 2022 and is supported by a broad coalition of member states: Austria, Belgium, Finland, France, Germany, Hungary, Italy, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, and the United Kingdom. Contracts for the development of the fleet were awarded in 2024 to two consortia involving more than 50 entities from 14 countries, demonstrating the strength of European industrial cooperation.

The demonstration mission covers the entire process: from the definition and development of the space and user segments, through the launch and establishment of the ground segment for operations, to the experimentation and demonstration of new services and, finally, the safe disposal of the satellites at the end of the mission. The success of the Celeste mission will open the door to new commercial applications, from autonomous vehicles and drones to the Internet of Things (IoT) and smart cities, further strengthening Europe's technological sovereignty and competitiveness on the global stage. More information about the mission can be found on the official ESA website at www.esa.int/LEO-PNT.