A 3-Year Prototype Just Triggered Europe's Largest Weather Satellite Order in Decades

OHB Sweden has won a contract worth 248 million euros to build the most consequential piece of European weather infrastructure in a generation.

The company signed the contract March 18 with ESA on behalf of EUMETSAT for the EPS-Sterna constellation: 20 satellites across three operational generations, plus two flight spares, designed to monitor atmospheric conditions over the polar regions continuously from 2029 through at least 2042. The initial block of six satellites is scheduled to launch in 2029, operating from sun-synchronous polar orbits at 595 kilometers altitude. Each satellite weighs 135 kilograms and carries a microwave sounding radiometer payload.

The program is a direct descendant of the Arctic Weather Satellite, a prototype OHB Sweden built and delivered in three years — fast by traditional space-program standards. AWS launched and immediately began having its data assimilated into operational weather forecasts at the European Centre for Medium-Range Weather Forecasts, a validation that does not usually happen for a demonstrator mission. The success of that satellite made EPS-Sterna possible: the constellation is in effect an industrialized version of what AWS proved could work.

EUMETSAT, which will operate the satellites and develop the ground segment, has stated that EPS-Sterna data are projected to generate more than 30 billion euros in economic value for Europe. That number reflects the avoided costs of weather-related disasters, improved agricultural planning, and more efficient energy grid management across a continent where Arctic weather dynamics increasingly drive conditions in the Mediterranean and across the Northern Hemisphere.

The industrial dimension matters as much as the meteorological one. OHB Sweden's team spans approximately 30 companies across Europe, with Sweden and Germany as the primary industrial hubs. For Sweden specifically, this contract marks a transition from contributing subsystems and components to leading a full satellite constellation — a capability step that has strategic implications beyond weather data. The fact that the AWS prototype cleared the operational bar so quickly suggests the New Space development model can work for operational meteorological infrastructure, not just for demonstration missions.

Europe's independent Earth observation capability has new urgency as climate change intensifies weather variability in the Arctic, with downstream effects on European weather patterns. The constellation's microwave sounders will provide high-quality atmospheric data from polar regions that existing systems cover less completely. The data will also complement observations from EUMETSAT's own larger platforms and from NOAA's polar-orbiting satellites and China's Fengyun-3 program — meaning EPS-Sterna fills a specific gap rather than simply duplicating existing assets.

One older mission is ending around the same time the new constellation comes online. Odin, a Swedish-developed satellite launched in February 2001 with a planned two-year operational lifetime, is expected to reenter the atmosphere in the second quarter of 2026 — more than 25 years after launch. It will have been operating continuously well beyond its design life. The handoff from Odin to EPS-Sterna is not just a program transition; it is a generational shift in European polar monitoring capability.

Sources: ESA press release (March 2026), EUMETSAT EPS-Sterna program page, SpaceNews.