ESA’s HydroGNSS Mission Set to Launch Twin Satellites for Global Water Cycle Monitoring

The European Space Agency (ESA) is set to launch its HydroGNSS mission, an innovative twin-satellite initiative aimed at monitoring Earth’s water cycle, on 19 November at 19:18 CET (10:18 Pacific Time). The launch will take place at Vandenberg Space Force Base, with SpaceX facilitating the operation using its Falcon 9 rocket. Live coverage of the event will begin at 19:01 CET (10:01 Pacific Time) and can be viewed on ESA Web TV.

HydroGNSS is expected to play a vital role in understanding alterations in global hydrology, a critical area of concern for environmental sustainability and community welfare. The mission is part of ESA’s FutureEO program and will focus on measuring four significant hydrological parameters: soil moisture, wetland inundation, freeze/thaw cycles, and above-ground biomass. These measurements are aligned with Essential Climate Variables, which are crucial for assessing climate-related risks through empirical data.

The data gathered by HydroGNSS will have broad applications, ranging from weather predictions and flood forecasting to insights into wetlands, permafrost dynamics, and forest carbon metrics. In addition, the mission will provide secondary measurements such as ocean wind speeds and sea-ice extent. HydroGNSS employs a sophisticated technique known as Global Navigation Satellite System (GNSS) reflectometry. This process analyzes changes in GNSS signals—originating from satellites like Galileo and GPS—as they reflect off Earth’s various surfaces.

The mission comprises two microsatellites orbiting approximately 550 kilometers apart, each equipped with GNSS reflectometry instruments. This satellite arrangement allows for comprehensive data collection on water-related indicators by comparing reflected signals with the direct signals sent from GNSS satellites.

In conjunction with HydroGNSS, the launch will also include satellites for Italy’s IRIDE mission, which aims to bolster public sector services through enhanced Earth observation capabilities. This phase of IRIDE, known as the Eaglet II constellation, features satellites equipped with high-resolution multispectral instruments. Funded by Italy’s National Recovery and Resilience Plan and coordinated by ESA, these satellites are intended to provide critical support for the Italian public authorities and civil protection efforts.

Additionally, Greece will see the deployment of two high-resolution ICEYE radar satellites under its National Small Satellite Programme. This initiative aspires to strengthen Greece’s technological capabilities and foster economic growth, with a focus on disaster management and environmental monitoring. The project is being led by the Hellenic Space Center and the Greek Ministry of Digital Governance, with oversight from ESA.

The HydroGNSS mission represents a significant step forward in the use of space technology for addressing pressing global environmental issues, showcasing the potential of collaborative efforts in space exploration.