Overview
- The pair launched on 28 November aboard a SpaceX rocket as ESA’s inaugural Scout mission and has begun on-orbit operations.
- Built by Surrey Satellite Technology Ltd in Guildford with £26 million from the UK Space Agency, HydroGNSS was delivered in about three years on a €35 million budget.
- Each spacecraft carries a delay Doppler mapping receiver with one antenna for direct GNSS signals and another for surface reflections to retrieve soil moisture, inundation, biomass, and freeze–thaw state.
- ESA says the mission will supply near-real-time, high-frequency measurements to strengthen flood forecasting, weather models, agricultural planning, and wetland monitoring.
- The data stream will complement ESA’s SMOS and Biomass missions and NASA’s SMAP by adding cost‑efficient, rapid‑revisit hydrological observations.