The Italian project CASSANDRA is part of the international framework of the Synoptic Arctic Survey which seeks to collect oceanographic data in the Arctic Ocean in the two-year period 2020-2021 involving the coordination of many research vessels belonging to different nations. The aim is to determine the current state and major ongoing changes in the Arctic marine system by generating an oceanographic dataset that allows for a comprehensive characterization of Arctic hydrography and circulation, carbon uptake and ocean acidification, the distribution of possible pollutants, the functioning and productivity of organisms and ecosystems.