On January 12, 2026, the EUMETSAT Council formally approved the EUMETSAT Polar System – Sterna (EPS-Sterna), a multi-satellite meteorological constellation designed to provide high-frequency microwave sounding observations. The decision, backed by 29 of the organization’s 30 member states, authorizes the full-scale implementation of a program estimated to cost approximately €1 billion.
The first generation of six microsatellites is scheduled for launch in 2029, following the successful operational validation of the prototype Arctic Weather Satellite (AWS).
From Prototype to Operational Infrastructure
The approval of EPS-Sterna follows the orbital performance of the Arctic Weather Satellite, which launched on August 16, 2024. Developed under the European Space Agency (ESA) Earth Watch program, the AWS demonstrator was designed to show that low-cost, rapidly built microsatellites could deliver data comparable to larger, traditional meteorological missions. By April 2025, ESA confirmed that the AWS was performing on par with heritage systems, providing critical measurements of atmospheric water vapor and temperature that were subsequently integrated into operational forecasts by the European Centre for Medium-Range Weather Forecasts (ECMWF).
Technical Specifications and Economic Impact
The EPS-Sterna constellation will eventually comprise 20 satellites to ensure continuous global data delivery through 2042. Each 125 kg microsatellite, based on the OHB Sweden InnoSat platform, will carry an identical 19-channel cross-track scanning microwave radiometer provided by AAC Clyde Space. By operating in multiple orbital planes, the constellation will achieve a revisit time of less than three hours globally, with data latency of approximately one hour. EUMETSAT projections indicate the program will generate €30 billion in economic value for Europe, driven by improved accuracy in predicting severe weather events, storm tracks, and precipitation intensity.
Executive Endorsement
“The strong backing from EUMETSAT’s member states shows the critical role EPS-Sterna will play in enabling national meteorological and hydrological services to forecast such events – which will have tremendous benefits for the lives and livelihoods of European citizens,” stated Phil Evans, Director-General of EUMETSAT.
Procurement and Deployment Timeline
Following the Council’s green light, ESA will manage the procurement of the Sterna satellites on behalf of EUMETSAT, maintaining a cooperation model similar to the Meteosat and MetOp programs. The initial deployment phase includes the launch of six satellites in 2029. These will be replaced in two subsequent tranches to maintain the 13-year operational lifespan of the mission. EUMETSAT will oversee the development of the ground segment, launcher procurement, and data distribution through the EUMETCast and EUMETView platforms.
