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Ultra-low-noise amplifiers developed by European Engineering Consultancy Ltd. (EECL) are operating in orbit on the European Space Agency’s (ESA’s) HydroGNSS mission, marking a technical milestone for the hardware following the satellites’ launch in November 2025.
HydroGNSS consists of two small satellites designed to measure hydrological and climate-related variables using GNSS reflectometry. The satellites collect signals transmitted by navigation satellites such as GPS and Galileo and analyze those signals after they reflect from Earth’s surface. The reflected signals provide data on environmental parameters including soil moisture, freeze–thaw conditions in permafrost regions, wetlands and inundation, and above-ground biomass.
The satellites were launched aboard a SpaceX Falcon 9 rideshare mission from Vandenberg Space Force Base in California on Nov. 28, 2025. The mission is part of the European Space Agency’s Scout program, which focuses on relatively small and cost-effective Earth observation satellites designed to demonstrate new measurement techniques.
EECL designed and manufactured six multiband ultra-low-noise microwave amplifiers used in the spacecraft payload. The amplifiers are part of the radio-frequency front end of the receiver system and are designed to amplify very weak reflected GNSS signals while minimizing additional noise, helping preserve signal quality for scientific analysis.
Early on-orbit results indicate the satellites’ payloads are functioning as expected. Both spacecraft have begun collecting delay-Doppler maps of reflected GNSS signals, an early step in commissioning that confirms the receivers are acquiring and processing signals properly.
The HydroGNSS satellites were built by Surrey Satellite Technology Ltd., which also developed the GNSS receiver used on the mission. The spacecraft operate in low Earth orbit and are phased apart to increase global coverage of the measurements.
Data from HydroGNSS are expected to support research on the global water cycle and contribute to studies related to climate monitoring, agriculture, flood risk and ecosystem changes.