The European Space Agency (ESA) is preparing to launch its pioneering HydroGNSS mission. This mission, a true twin-satellite system, will provide refinements of understanding unparalleled in the history of Earth’s water cycle. Launch of the HydroGNSS satellites is planned for November. They’ll use signals from today’s Global Navigation Satellite Systems (GNSS) to gather critical new data on climate-related variables.
HydroGNSS represents ESA’s first entry into the “Scout” mission class, which are missions that are quickly developed and quickly launched. The mission is a flagship mission of the Earth Observation FutureEO program. It seeks to unlock powerful observations through GNSS reflectometry, a remote sensing approach that uses signals reflected off surfaces such as land, ice, and oceans.
The HydroGNSS mission will consist of two identical microsatellites that will orbit the Earth 180 degrees apart. Unlike traditional Earth observation satellites, these satellites will predominantly measure reflected GNSS signals from global systems such as Galileo and GPS. Further, they’ll compare these signals against direct GNSS signals. This comparison will produce important insights about geophysical parameters associated with the changing water cycle.
Scientists will focus on four key variables with the HydroGNSS mission: soil moisture, freeze-thaw state over permafrost, inundation, and above-ground biomass. These satellites will gather unprecedented amounts of data that can help farmers make real, meaningful improvements in agricultural planning. In addition, they’ll improve flood forecasting, develop our understanding of wetlands and permafrost dynamics, and forest carbon storage.
The HydroGNSS multi-satellite constellation will launch one-by-one aboard a SpaceX Falcon 9 rocket flying from Vandenberg Space Force Base. ESA’s dedication to efficiency can be seen all throughout this mission. Each Scout mission has to move from kick-off to launch in only three years while adhering to a strict budget ceiling of €35 million.