Salt hydrates at high pressure and low temperature: Implications for icy moon explorations

The icy moons of Jupiter and Saturn, such as Europa, Ganymede, and Enceladus, are thought to contain a saltwater ocean beneath their icy crust. This raises the intriguing question of whether these moons can sustain habitats for life. The cycle of the salts in solution and in solid form as hydrates are key for shaping the internal structures, compositions and evolutions of these icy worlds, and can play a crucial role in promoting habitable conditions. Yet little is known about the structures that water and salt adopt at the high pressure and low temperature conditions relevant for icy moon conditions. Here we propose to conduct high-pressure and low temperature in-situ single crystal diffraction experiments to characterise new forms of KCl, CaCl2, and K2CO3 salt hydrates and thus build their phase diagrams for the conditions of the icy moons. This work will form a basis for identifying salt hydrates in the space missions, such as NASA Europa Clipper and the ESA JUICE.