GALENE: A proposed future satellite mission dedicated to the observation of coastal and inland aquatic ecosystems, including the monitoring of water quality and the detection of marine plastics

Coastal and inland aquatic ecosystems are of fundamental interest to society and economy, given their tight link to urbanization and economic value creation. These ecosystems, which are continuously impacted by natural processes and human activities such as litter pollution, including marine plastics, play a significant role in the carbon cycle, and they comprise critical habitats for biodiversity. Particularly, improved knowledge of distributions of marine plastics is becoming critical. Systematic, high-quality and global observations, such as those provided by satellite remote sensing techniques, are key to understand complex aquatic systems. While multitudes of remote sensing missions have been specifically designed for studying ocean biology and biogeochemistry as well as for evaluating terrestrial environments, missions dedicated to studying critical coastal and inland aquatic ecosystems at global scale are non-existent. Thus, these ecosystems remain among the most understudied habitats on the Earth’s surface. A satellite mission called Global Assessment of Limnological, Estuarine and Neritic Ecosystems (GALENE), is proposed to ESA’s Earth Explorer Mission Idea call to respond to current and future challenges linked to coastal and inland ecosystems. The mission concept consists of a synergy of three innovative instruments, namely a hyperspectral sensor, a panchromatic camera and a polarimeter. GALENE will then provide optimized measurements of these aquatic ecosystems by enabling an adaptive spectral, spatial, multidirectional and polarimetric sampling of properties and processes in water column, benthic habitats and associated wetlands. GALENE will substantially contribute to solving global water challenges, including the marine plastic detection, water pollution and ensuring clean drinking water supply for all and protecting coastal areas and populations. In particular, co-located hyperspectral and multi-angular polarized measurements will consolidate the capacity for providing descriptors of plastics. The GALENE science objectives and the main innovative features will be presented.