New Water-Tracking Satellites to Help Understand Our Climate

The European Space Agency's (ESA) HydroGNSS mission is a pioneering effort to use a clever technique called 'GNSS reflectometry' to study Earth's water cycle. Instead of sending out its own signals, HydroGNSS will listen for signals that are already being transmitted by navigation satellites like GPS and Galileo. When these signals bounce off the Earth's surface, they carry information about the properties of the land and water they interacted with. By analyzing these reflected signals, HydroGNSS can gather data on key variables like soil moisture, the extent of wetlands, and even the freeze-thaw state of the ground. The HydroGNSS mission consists of two small satellites, making it ESA's first 'Scout' mission. Scout missions are designed to be cost-effective and agile, allowing for quicker development and deployment of innovative technologies. This approach helps to accelerate scientific discovery and address pressing environmental challenges. Traditional methods of monitoring these variables often rely on direct measurements from the ground, which can be limited in coverage and difficult to obtain in remote areas. HydroGNSS offers a way to overcome these limitations by providing a global, consistent view of Earth's water cycle. The data collected by the mission will complement existing observations and improve the accuracy of climate models. This mission is particularly important in the face of climate change. As temperatures rise, the Earth's water cycle is becoming more erratic, with some regions experiencing more intense droughts and others facing increased flooding. Accurate monitoring of water resources is essential for managing these risks and adapting to a changing climate.