The HydroGNSS satellite. Concept image by ESA.

Surrey Satellite Technology Ltd. (SSTL) has won a deal with the European Space Agency (ESA) to build and operate ‘HydroGNSS’ — the agency’s second Scout Earth Observation small satellite mission. HydroGNSS is a 40 kg satellite that will take measurements of key hydrological climate variables, including soil moisture, freeze thaw state over permafrost, inundation and wetlands, and above ground biomass, using a technique called GNSS Reflectometry.

HydroGNSS and ESP-MACCS (announced in December 2020) are the first two in a series of ESA Scout missions demonstrating: how small satellites can be built on a budget of less than 30 million euros ($35.33 million); how a three-year schedule can play an important role in Earth Observation; and how this can be scaled up for future similar missions.

SSTL is working closely with partners at Sapienza, Tor Vergata and IFAC-CNR in Italy, FMI in Finland, IEC/IEEC in Spain, NOC in UK, and University of Nottingham to tackle the scientific and technological challenges involved.

“SSTL pioneered GNSS Reflectometry, providing the payloads on TechDemoSat-1 and the NASA CYGNSS mission for measuring ocean wind speeds, and I am delighted that we will now launch the first satellite mission specifically addressing hydrological measurements using this innovative technique,” Phil Brownnett, Managing Director of SSTL said in a statement.