The first demonstrator satellite in the European Space Agency’s Celeste programme has been successfully launched from New Zealand, marking the start of in-orbit testing of low Earth orbit positioning, navigation and timing technology.
Celeste IOD-1, developed by Madrid-based GMV and Alén Space, lifted off from Rocket Lab’s Launch Complex 1 in Māhia, New Zealand, on March 28 at 10:14 CET. The satellite separated from the launcher approximately one hour later and has now entered its early operations phase, during which mission control will prepare it for operational life in orbit.
A second demonstrator satellite, IOD-2, developed by Thales Alenia Space under a parallel ESA contract, was launched on the same vehicle.
What is Celeste?
Celeste is ESA’s strategic programme to demonstrate the benefits of an additional low Earth orbit (LEO) navigation layer that complements the existing Galileo and EGNOS systems. The programme aims to improve the accuracy, resilience and security of positioning, navigation and timing (PNT) services across Europe.
The in-orbit demonstrator (IOD) phase represents the programme’s first stage, validating key LEO-PNT technologies in flight ahead of any potential future operational deployment.
GMV was selected in 2024 to lead one of two parallel prime contracts for Celeste’s development. The company is responsible for the end-to-end mission for six of the eleven demonstrator satellites, covering system definition and design, space and ground segments, user segment, and operations. The IOD phase is being carried out by two European consortia, with a total of eleven satellites plus one in-orbit spare planned.
Technical scope
Celeste IOD-1 is a 12U CubeSat that has undergone assembly, integration, and rigorous environmental and system testing at GMV’s facilities. The programme will demonstrate:
- Precise autonomous orbit determination without reliance on ground infrastructure
- Stronger radionavigation signals in the L- and S-bands from LEO
- The advantages of integrating LEO capabilities into a multi-orbit architecture alongside Galileo in medium Earth orbit (MEO)
The demonstrators operate at altitudes between 500 and 560 km. Eight additional, larger satellites are currently under development to extend the capabilities of the initial demonstrators, with subsequent launches planned from 2027.
In December 2025, GMV completed the Flight Readiness Key Point (FRKP) – a milestone verifying the satellite’s readiness for launch, overseen by an ESA delegation at GMV’s headquarters in Tres Cantos, Madrid.
“Celeste marks the beginning of a new era for satellite navigation in Europe,” says Miguel Romay, director of satellite navigation systems at GMV. “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.”
IOD-1 and IOD-2 will initially focus on securing registered frequency allocations and testing representative navigation signals through the end of 2026, before the expanded fleet begins to demonstrate the full potential of a complementary LEO layer for Europe’s navigation infrastructure.
