Surface Water Investigations on Mars

Experiments are presented which explore whether a layer of liquid water forms at the ice table in the shallow subsurface due to contact between perchlorate and water ice on Mars. Samples of regolith simulant were mixed with varying concentrations of magnesium perchlorate and deposited over ice to simulate the ice-regolith interface as was seen on Mars. Over multiple temperature cycles, the temperatures of melting of the ice and full freezing of the resulting brine were recorded using an embedded moisture sensing device. Based on temperatures simulated to constrain the ice table at the Phoenix landing site, a perchlorate concentration of 5% is sufficient for a layer of liquid water to form which can persist for days at a time, while no liquid forms for a Mars-measured concentration of 0.6%. Other concentrations are also explored.