Europe’s weather satellite agency has approved a major new space-based observation programme that is expected to significantly improve weather forecasting accuracy while delivering substantial long-term economic benefits, a development with implications for global forecasting systems and climate resilience planning.
The EUMETSAT Council has formally given the green light to the EUMETSAT Polar System – Sterna (EPS-Sterna), a constellation of polar-orbiting microsatellites designed to deliver microwave measurements of atmospheric temperature, humidity and cloud structure at an unprecedented frequency. The system is scheduled to deploy its first satellites in 2029 and operate through to 2042.
The approval follows votes taken during the 110th session of the EUMETSAT Council, where 29 of the organisation’s 30 member states backed the programme. That near-unanimous support confirms EPS-Sterna as a mandatory mission and authorises the start of all programme activities, including satellite procurement, ground infrastructure development and launch preparation.
According to EUMETSAT, data generated by EPS-Sterna are projected to deliver at least €30 billion in economic value to Europe over the programme’s lifetime, with a benefit-cost ratio of up to 51:1. The gains are expected to come from improved forecasting accuracy that enables better-informed decisions across sectors such as emergency management, transportation, energy, agriculture and insurance, as well as enhanced protection of life and property.
The programme has been under consultation since 2022, reflecting the scale of investment and the strategic importance of polar-orbiting satellite data to Europe’s weather and climate services. The approval comes against a backdrop of increasingly severe and frequent extreme weather events across the continent.
“Recent years have brought record heatwaves, devastating storms, floods and wildfires across Europe,” said Phil Evans, Director-General of EUMETSAT. “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. Getting here has taken outstanding dedication from member states and the teams involved and we now look forward to delivering this critical programme together with our partners.”
EPS-Sterna will consist of multiple identical microsatellites operating in different orbital planes to dramatically increase the frequency of observations. The first six satellites are scheduled for launch in 2029, with additional satellites deployed over time to maintain continuous operations until 2042. In total, 20 satellites will be launched during the programme’s lifetime.
Once operational, the constellation will provide near-global coverage, revisiting the same location on Earth in less than three hours. Most data will be available to users within approximately one hour of observation. This represents a substantial improvement over current polar satellite systems, which typically observe the same area only twice per day.
The increased observation frequency is expected to be particularly valuable for forecasting severe weather in sensitive regions such as the Mediterranean, as well as addressing long-standing data gaps over the Arctic. The Arctic is the fastest-warming region on the planet and a key area where many weather systems affecting Europe originate or intensify, making improved monitoring there a strategic priority.
The EPS-Sterna programme builds on technology already proven in orbit. It draws directly from the European Space Agency’s Arctic Weather Satellite (AWS), which has been collecting data since August 2024. Those data are already being assimilated by national meteorological and hydrological services in EUMETSAT member states, providing early confirmation of the benefits anticipated from a larger constellation.
The satellites will carry advanced microwave sounders capable of measuring atmospheric conditions through cloud, rain and snow—an advantage over instruments that rely on visible or infrared radiation. Impact studies indicate EPS-Sterna could reduce forecast error by up to 6 per cent across EUMETSAT member states and as much as 9 per cent in the Arctic, improving predictions of storm tracks, precipitation timing and intensity, and temperature extremes.
Under the programme structure, the satellites will be procured by EUMETSAT through the European Space Agency. EUMETSAT will be responsible for developing and managing the ground segment, procuring launch services, commissioning and operating the constellation, and distributing data through established platforms including EUMETCast and EUMETView.
With formal approval secured and funding commitments in place, EPS-Sterna now moves from planning to execution, positioning Europe to strengthen its weather forecasting capabilities at a time when climate-driven extremes are placing growing pressure on economies and public safety systems worldwide.
