The primary objective of the SMAP mission is to assess the moisture content of the surface soil layer and its state (frozen or thawed). Another pioneering reconnaissance mission of the European Space Agency, the HydroGNSS satellites, has become an important step in expanding global understanding of water availability and the impact of climate change on the global water cycle. The SWOT (Surface Water and Ocean Topography) satellite allows for the assessment of river discharge, defined as the volume of water flowing per second at a given point along the river.