The UK has taken significant steps in space-based climate monitoring following the successful launch of HydroGNSS, a pair of satellites designed to track key elements of the Earth’s water cycle
Launched on 28 November aboard a SpaceX rocket, the mission marks the inaugural satellite deployment under the European Space Agency’s (ESA) Scout programme. It shows the UK’s continuing leadership in low-cost, rapid-deployment Earth observation technology.
Advancing climate science through UK innovation
HydroGNSS was designed and built by Surrey Satellite Technology Ltd (SSTL) in Guildford and supported by £26 million in funding from the UK Space Agency. The mission demonstrates advancement in the UK’s industrial and scientific expertise and a strategic contribution to global efforts to monitor environmental change.
Now operating in orbit, the satellites are set to deliver essential data on the movement and behaviour of water across the planet. Their measurements will provide insight into soil moisture, flooding potential, surface water accumulation, freeze–thaw conditions, and the extent of global vegetation cover. This dataset is expected to support improvements in weather forecasting, flood prediction models, agricultural planning, ecosystem monitoring, and long-term climate research.
Paul Clements, Director of Operations at the Environment Agency, said:
“Climate change means more frequent and severe environmental incidents across the UK. Now more than ever, we must harness cutting-edge technology to develop the tools we need to protect communities from flooding and other hazards.
“The launch of this new mission is a compelling example of how British leadership and expertise in space delivers real, tangible benefits to the public.
“The enhanced data it provides will significantly strengthen our flood forecasting and warning capabilities, enabling a more effective operational response to safeguard lives, property, and infrastructure.”
Innovative GNSS reflectometry technology
HydroGNSS uses an advanced technique known as GNSS Reflectometry. Instead of relying on traditional Earth observation sensors, the satellites collect signals reflected from the Earth’s surface by existing navigation satellites, such as GPS.
This approach enables missions to capture data even in conditions that typically obscure observations, such as dense cloud cover and forest canopies.
The technology offers a cost-effective, resilient method for tracking hydrological variables at a global scale. Its rapid revisit times and wide coverage make it especially valuable for monitoring the evolving impacts of climate change, including extreme weather events and shifting environmental patterns.
Global environmental monitoring
The HydroGNSS mission improves the broader international portfolio of climate-monitoring satellites. It complements ESA’s SMOS and Biomass missions, as well as NASA’s SMAP satellite, by adding cost-efficient, high-frequency measurements of hydrological indicators.
The continuous data stream delivered by HydroGNSS is expected to feed into climate models that inform disaster response strategies, agricultural policies, and long-term scientific assessments of planetary health.
The satellites represent SSTL’s 75th and 76th spacecraft, launched during the company’s 40th anniversary year. Their deployment also highlights the growing maturity of the UK’s Earth observation sector within the broader European space ecosystem.
A sector set for growth
The launch comes at a critical moment for the UK Space Agency, as it prepares to integrate into the Department for Science, Innovation and Technology (DSIT) from April 2026. The merger will consolidate strategic and policy functions and is expected to streamline the government’s approach to supporting the space economy.
The UK currently invests heavily in European space initiatives, including a recently agreed £1.7 billion contribution to ESA programmes, bringing total UK commitments to £2.8 billion over the next decade. The national space sector now generates £18.6 billion in annual income and supports more than 55,000 jobs, underscoring its importance to both economic growth and national capability.
