Celeste before launch: Europe opens a new chapter of satellite navigation from low Earth orbit
The first two satellites of the Celeste mission are expected to lift off no earlier than 25 March 2026 aboard an Electron rocket from the American-New Zealand company Rocket Lab, from the Māhia launch complex in New Zealand. In doing so, the European Space Agency, ESA, is launching the first European demonstration mission for satellite navigation in low Earth orbit, known by the acronym LEO-PNT, or Positioning, Navigation and Timing. This is a project that could significantly change in the coming years the way Europe builds the resilience of its navigation and timing systems, especially in circumstances when conventional signals are weakened, obstructed or exposed to interference. In its first phase, Celeste does not replace Galileo, but is intended to complement and test it so that the European satellite navigation system is more robust, more available and technologically more ready for new types of services.
Celeste comes at a time when satellite navigation is no longer viewed only as infrastructure for guiding cars or determining position on smartphones. Systems for precise positioning and time synchronisation are now essential for air, maritime and rail transport, telecommunications networks, critical infrastructure, financial transactions, emergency services and various automated industrial processes. That is precisely why ESA sees a strategic leap in this mission: the creation of an additional navigation layer closer to Earth, which could improve signal availability and offer greater resilience in demanding conditions of use.
Why Celeste is important for Europe
Galileo, the European global satellite navigation system, operates from medium Earth orbit, and Celeste is meant to show what is gained when navigation satellites are moved significantly lower, to an altitude of approximately 500 to 560 kilometres. ESA states that such an approach enables stronger and faster radionavigation signals and opens room for testing new frequency bands. In practical terms, this means that a signal from low orbit could be more useful in urban canyons, in northern and Arctic areas, in environments where there are obstacles or an increased risk of interference, and in applications that require greater reliability and resilience.
It is also important that the project is not viewed in isolation. ESA describes Celeste as part of a broader multilayered approach in which future systems from low orbit would work together with Galileo, EGNOS and other global navigation systems. In this way, not only is an additional technological reserve being built, but also a framework for new services that may not be possible to obtain from the existing architecture in the same form. In the background there is also a broader European political and security logic: the resilience of space infrastructure is becoming a matter of strategic autonomy, and navigation and precise timing are among the fundamental digital services on which a large part of the modern economy depends.
Celeste simultaneously takes its place in ESA’s European Resilience from Space initiative, one of the new pillars of European thinking about space capacities. Such a framework shows that the project is not being run only as a technological experiment, but also as part of long-term thinking about European security, industrial capability and independence in critical space services. That is why the launch of the first two demonstrators is viewed as the beginning of a process, not as a goal in itself.
The first phase: two demonstrators to verify technology and frequencies
In the first stage of the mission, two demonstration satellites, designated IOD-1 and IOD-2, are going into orbit. ESA points out that they will serve to secure and test the allocated frequency filings and to transmit representative navigation signals until the end of the year. In other words, the first two satellites have a dual task: to technically show that the European LEO-PNT concept can function in real orbital conditions and at the same time confirm the regulatory and operational assumptions for a broader future constellation.
Both satellites belong to the category of large CubeSat spacecraft, but they are not of the same dimensions. One has a 12U configuration and the other 16U. Behind them stand two separate industrial consortia with broad European participation. One is led by the Spanish company GMV, with OHB from Germany as a key partner, while the other is led by Thales Alenia Space in France, with Thales Alenia Space in Italy as the holder of the space segment. According to ESA data, more than 50 entities from more than 14 countries are participating in the fleet’s development, which also makes Celeste an important industrial project for the European space sector.
For both demonstrators, the testing and qualification campaign has been completed. ESA states that in recent months payload integration, radio-frequency compatibility checks and environmental qualification, including thermal-vacuum, mechanical and electromagnetic tests, have been successfully carried out. This is a standard but exceptionally important part of preparation because small spacecraft in demonstration programmes must prove that they can withstand the conditions of launch and operation in orbit, especially when they carry technologies that still need to be validated in real conditions.
What the satellites will test in orbit
In technical terms, Celeste goes beyond simply sending two more satellites into space. The first two demonstrators should enable in-orbit testing of a series of technologies that ESA considers crucial for the next generation of European navigation services. Among them, autonomous precise orbit determination without relying on ground infrastructure is particularly prominent. Such a capability is important because it reduces operational dependence on external system segments and increases the resilience of the entire architecture.
In addition, ESA announces the testing of stronger and faster radionavigation signals in the L and S bands from low orbit. In a later phase, additional signals are also planned in other frequency areas, including the C band and UHF. This is precisely where one of the most interesting dimensions of the project lies: instead of Europe relying exclusively on existing navigation approaches, Celeste serves as an orbital test platform on which new combinations of frequencies, waveforms and service models can be verified.
ESA also states that such technologies could be particularly useful for autonomous vehicles, rail and maritime transport, aviation, critical infrastructure, wireless networks, emergency services, 5G applications and a number of other areas. Additional emphasis is placed on resilience against intentional and natural interference. At a time when jamming and spoofing of navigation signals have become a serious security issue, the development of alternative and complementary signal layers is also gaining clear geopolitical significance.
Delay due to weather and final preparations in New Zealand
Although earlier announcements mentioned a window starting on 24 March 2026, ESA announced on 19 March that due to weather conditions the launch had been moved to a date no earlier than Wednesday, 25 March. Such schedule changes are not unusual in space operations because meteorological conditions, the state of the launch infrastructure and the readiness of all systems are part of the standard risk assessment immediately before liftoff. In the case of missions that depend on close coordination between the launch operator, satellite manufacturers and the mission customer, even a minor delay can be important in order to avoid unnecessary technical and safety compromises.
According to ESA’s chronological overview of the campaign, the satellites were first transported from Madrid and the Italian city of L’Aquila to Berlin, where they were integrated into the launch dispenser at Exolaunch facilities. After that, they arrived separately in New Zealand: IOD-1 on 20 February and IOD-2 on 3 March, thereby officially opening the final pre-launch campaign. After arrival, they were transferred by road from Auckland Airport to the Māhia launch complex, where functional tests and spacecraft fuelling were carried out.
The launch site itself has in recent years become one of the more important commercial hubs for smaller orbital missions. Rocket Lab’s complex on the Māhia Peninsula is specialised for launches with the Electron rocket, a launcher used precisely for smaller satellites and technology demonstrators. For ESA, this means relatively flexible access to a launch service tailored to smaller spacecraft, while for Rocket Lab it confirms European confidence in commercial partners outside the continent when it comes to precisely targeted scientific and technological missions.
What follows after the first pair of satellites
Celeste is not conceived as a project limited to the first two CubeSats. ESA states that another eight larger satellites with additional capabilities are in development, with GMV and Thales Alenia Space responsible for four spacecraft each. In addition, one more extra satellite is planned with a payload for testing miniaturised atomic clocks and other technologies. This would bring the demonstration phase to a total of 11 satellites, as foreseen in the first full demonstration set.
These future satellites should expand the range of tested signals and services. ESA specifically mentions two-way navigation signals in the S band for advanced positioning capabilities using 5G satellite waveforms, the C band for greater resilience to jamming and interference, and UHF signals for better penetration and positioning indoors. At the level of the market and services, this means that Celeste could grow from a demonstrator into a key development platform for a wide range of applications, from logistics and asset tracking to public safety and communications networks.
According to ESA plans, additional launches could follow from 2027 onward. In addition, at the ESA ministerial council in November 2025, the next phase of the project, called the in-orbit preparatory phase, was also confirmed. That stage should encompass technological development, industrialisation and in-orbit validation as preparation for a possible operational system within the European GNSS infrastructure, together with Galileo and EGNOS. In other words, Celeste is not a short-term experiment, but a potential foundation for a future institutional navigation component of the European Union.
Industrial and political signal of European ambition
The project is also important because it shows how Europe is trying to connect institutional goals, industrial development and technological demonstration. The awarding of two parallel contracts to different consortia in itself points to a model in which competition, diversity of solutions and broader involvement of the European industrial base are encouraged. This can accelerate development, reduce technological risk and open greater space for the involvement of specialised companies, research centres and suppliers.
At the same time, Celeste is arriving at a time when Europe is discussing ever more openly the resilience of its critical systems in circumstances of heightened security and geopolitical tensions. Satellite navigation and precise timing are not visible every day, but without them modern states and economies can hardly function to their full extent. Because of this, every step towards a multilayered, more resilient and technologically more diverse architecture has a broader meaning than the space industry alone.
For the European states financing the project, the fact that Celeste brings together a large number of partners from several countries while at the same time opening the possibility for future services to be developed in cooperation with end users is also important. ESA has already opened the door to interested third parties from participating states for inclusion in the mission’s experimental phase. Such an approach suggests that not only technical success in orbit is expected from Celeste, but also the creation of a concrete ecosystem of future services and business models.
The first launch is therefore much more than a routine departure of two small spacecraft into orbit. It represents a test of Europe’s ability to move from theory to operational demonstration, to verify new signals and new frequency approaches in real conditions, and to prepare the ground for a system that could complement the continent’s existing navigation infrastructure in the next decade. If Celeste succeeds in confirming the expectations set for the first phase, Europe will gain not only another space project, but also an important argument that the future of satellite navigation will not depend on one orbital layer, one technology or one service model.
Sources:- European Space Agency (ESA) – official announcement on the confirmed target launch date, the weather delay and the technical goals of the first phase of the Celeste mission.- European Space Agency (ESA) – chronology of the pre-launch campaign, the satellites’ arrival in New Zealand and final preparations at the Māhia complex.- European Space Agency (ESA) – overview of the broader Celeste concept, the planned demonstration constellation and the application areas of the LEO-PNT system.- European Space Agency (ESA) – official mission page describing the relationship of Celeste to Galileo, EGNOS and the future multilayered navigation approach.
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