Celeste IOD-1, developed by GMV and Alén Space under the European Space Agency’s (ESA) Celeste In-Orbit Demonstrator (IOD) program, was successfully launched on March 28 from Rocket Lab’s Launch Complex 1 in Mahia, New Zealand. The two satellites – built respectively by GMV and Thales Alenia Space - were launched at 10:14 CET and separated from the launcher about an hour later. This marks the beginning of their early operations phase, during which mission control gets them ready for life in orbit.

Celeste is ESA’s strategic program to demonstrate the benefits of an additional low Earth orbit (LEO) navigation layer that complements Galileo and EGNOS, with the goal of improving the accuracy, resilience, and security of positioning, navigation, and timing (PNT) services in Europe. The in-orbit demonstrator (IOD) represents the program’s first phase and will validate key LEO-PNT technologies in flight ahead of potential future operational deployment.

The Celeste IOD phase is being carried out in parallel by two European consortia and will include a total of eleven satellites plus one in-orbit spare. As one of the prime contractors, GMV is responsible for the end-to-end mission for six of the demonstrator satellites, including system definition and design, the space and ground segments, the user segment, and operations.

Next-generation LEO navigation

The Celeste program will begin with two demonstrator satellites, IOD-1 and IOD-2, aimed at securing registered frequency allocations and testing representative navigation signals through the end of the year. The mission will demonstrate precise autonomous orbit determination without relying on ground infrastructure, as well as stronger radionavigation signals in the L- and S-bands from low Earth orbit.

By demonstrating the advantages of integrating LEO capabilities into a multi-orbit architecture alongside Galileo (MEO), Celeste aims to improve resilience to interference and expand advanced navigation services. Operating at altitudes between 500 and 560 km, the Celeste demonstrators will assess how a complementary LEO layer can enhance Europe’s Galileo system in medium Earth orbit. Eight additional, larger satellites are currently under development to extend the capabilities of the initial demonstrators. These will form part of the full fleet (eleven operational spacecraft and one spare) and will pave the way for subsequent launches starting in 2027.

GMV was selected in 2024 by the European Space Agency (ESA) to lead one of the parallel contracts for the development of Celeste. The first satellite in the constellation, a 12U CubeSat named Celeste IOD-1, was jointly developed by GMV and Alén Space. In recent months, Celeste IOD-1 has undergone a complex assembly and integration process, as well as rigorous environmental and system testing. The results of these tests, carried out at GMV’s facilities, confirmed that the satellite was ready for launch, as well as for initial LEOP (Launch and Early Orbit Phase) operations and in-orbit experimentation activities.

In December 2025, GMV completed the Flight Readiness Key Point (FRKP), a milestone aimed at verifying Celeste IOD-1’s readiness for launch. The milestone was overseen by an ESA delegation, which confirmed in the cleanroom at GMV’s headquarters that the satellite was fully assembled and ready for transport. During the visit, ESA inspected the satellite in its final configuration and toured the operations room and the Celeste mission control center, from which the satellite will be operated once in orbit. This demonstrated that both the satellite and the full operational support infrastructure are ready for the mission’s next phase. The latest results from navigation performance tests were also reviewed, confirming compliance with mission objectives.

According to Miguel Romay, GMV’s Director of Satellite Navigation Systems, “Celeste marks the beginning of a new era for satellite navigation in Europe. By incorporating satellites in low Earth orbit, the system gains in accuracy, resilience, and its ability to meet future user needs. GMV’s leadership in the Celeste demonstrator highlights the capabilities of the Spanish industry to develop complete navigation systems, from the satellite itself to the ground segment and operations.”

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