In recent years, semiconductor components and environmental measurement expertise from Chalmers have played a key role in advancing weather satellite technology. It has now been confirmed that microwave radiometers based on Chalmers research will be used in the European weather satellite programme EPS-Sterna – bringing significant benefits for future climate research.
The announcement follows a record-breaking order worth nearly SEK 820 million, placed by Swedish satellite manufacturer OHB Sweden for 20 microwave radiometers from the Gothenburg-based space company AAC Omnisys. OHB Sweden is the prime contractor for the weather satellites used within the European satellite programme EPS-Sterna, on behalf of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).
The satellites’ primary mission is to provide frequent measurements of atmospheric temperature and humidity for numerical weather prediction. The radiometer technology at the heart of these satellites is partly built on research and development conducted at Chalmers. The programme represents the latest milestone in a long-standing collaboration between Chalmers and the Swedish space industry, dating back to the 1990s and the development of the Odin satellite.
Patrick Eriksson, Professor of Geosciences and Remote Sensing at Chalmers, has been involved throughout the entire journey – from early research and instrument concepts to implementation and operational use.
“This is by far the largest order ever for Swedish companies in the field of satellite delivery,” says Eriksson. “This success builds on a series of national satellite initiatives and collaborations. For example, the Sterna programme would not exist without Sweden’s earlier investment in the Odin satellite, launched in 2001 and now performing its final measurements. It almost feels as if Odin held out until the Sterna contract was signed.”
Enabling groundbreaking atmospheric measurements
The Chalmers-developed radiometer technology makes it possible to measure how ice forms deep inside clouds – an essential piece of the puzzle for both weather forecasting and climate research. Clouds, and the processes within them, are key factors in understanding and predicting climate change.
“In simple terms, this technology allows us to determine the mass of clouds with greater accuracy than ever before,” Patrick Eriksson explains. “This is crucial for understanding cloud physics and validating climate models. With Sterna, we can also build long-term datasets to track how cloud patterns evolve as the climate changes.”
A central component of the technology is the semiconductor diodes developed at Chalmers and used in the radiometer receivers. These enable highly sensitive measurements of temperature, humidity, and ice within clouds.
“More specifically, it is a Schottky diode for the terahertz range that we have developed using nanotechnology in Chalmers’ cleanroom facility, Myfab. This semiconductor diode is used in several of the microwave radiometer’s receivers. These components make it possible to observe parts of the atmosphere with high accuracy,” says Jan Stake, Professor of Terahertz and Millimetre Wave Technology at Chalmers.
Proven success in orbit
This is not the first time Chalmers-based measurement technology has been deployed in space. In August 2024, the world’s first Arctic weather satellite, AWS, was launched using the same underlying technology. Equipped with a 19-channel microwave radiometer, the satellite has since delivered high-resolution data on temperature, humidity, and ice in clouds.
“The core idea behind AWS was to cost-effectively increase the types of measurements that have the greatest impact on global weather forecasting,” says Eriksson. “At the same time, we entered a completely new frequency range – sub-millimetre – to observe ice crystals in clouds. Despite some initial resistance, we succeeded in including a 325 GHz receiver, which has now proven to perform extremely well.”
Since mid-2025, AWS data have been used operationally by the European Centre for Medium-Range Weather Forecasts (ECMWF), where the instrument ranks among the best-performing satellite systems.
“AWS fills an important gap that other satellites cannot cover, and it clearly meets the high expectations placed on it,” Eriksson adds, who is also a visiting scientist at ECMWF.
More accurate forecasts with major societal benefits
The EPS-Sterna satellite constellation will build on these successes by deploying multiple satellites in orbit, enabling more frequent and detailed atmospheric measurements. The first satellites are scheduled for launch in 2029, and a total of 20 satellites will be deployed during the programme’s operational lifetime through 2042. This will significantly improve numerical weather models and strengthen early warning systems for extreme weather events.
With EPS-Sterna, Europe is taking a leading role in next-generation weather observation. The programme exemplifies a model in which cutting-edge academic research, industrial innovation, and operational forecasting are closely integrated.
“This shows how research at Chalmers can help address global societal challenges and highlights the importance of long-term collaboration with industry to translate laboratory results into benefits for society,” says Jan Stake.
- Full Professor, Geoscience and Remote Sensing, Space, Earth and Environment
- Full Professor, Terahertz and Millimetre Wave Laboratory, Microtechnology and Nanoscience