On 8th April, ESA’s Celeste mission reached a significant point when the first navigation signal from low Earth orbit was successfully transmitted. The signal came from Celeste IOD-1 and represents a historic first for Europe’s PNT efforts. It is the first dual‑frequency navigation message in the L- (1-2 GHz) and S-(2-4 GHz) bands transmitted from a European satellite in low-Earth orbit. A second signal from Celeste IOD-2 is expected to be transmitted in the coming days.
The Celeste satellites were launched on 28th March by Rocket Lab in New Zealand. GMV and Thales Alenia Space built them. The dual-band devices offer stronger signals, for a given power output, than ESA’s Galileo system due to their closer orbits. However, they are seen as complementary to Galileo, and not as replacements.
This development is described by ESA as an important early milestone in the Celeste commissioning and in‑orbit testing phase. After launch, the satellites completed their initial operations and were cleared for mission life. They are currently undergoing checks to verify vital subsystems, such as propulsion and attitude/orbit control, to ensure everything is ready for routine operations.
The transmissions also support regulatory processes, including the filing of the necessary L- and S-band frequencies for future European LEO‑PNT missions, in line with International Telecommunication Union regulations. Celeste thus contributes to Europe’s broader strategy by helping to establish a European, multi‑layer PNT capability and by supporting plans for an independent navigation layer in low Earth orbit that complements Galileo and EGNOS.
Celeste is a key part of ESA’s European Resilience from Space (ERS) initiative, which aims to strengthen security and resilience for member states while preparing future European space capabilities. The program’s results are expected to influence decisions about Europe’s space infrastructure and industry.
Published by James Hydzik
James Hydzik is a technology geek focused on the junction of engineering, writing, and coffee. He joined Orbital Today in 2020 to help make sense of the Johnson government’s decision to buy OneWeb. Since then, he has taken on interviewing and editor-in-chief roles. James learned the ropes of editing and writing with Financial Times magazines, The World Bank, PwC, and Ericsson. Thus far, interviewing New Space movers has put the biggest smile on his workaday face. The son of an Electrical Engineer, James understands the value of putting complex topics into clear language for those with a lay person’s understanding of the subject. James is a European transplant from the United States, and as ex-KA3LLL, he now holds European amateur radio licenses. His next radio project is a portable 10GHz EME (moonbounce) station, as it combines his childhood interests in antennas and space.