Accessible Water on Mars and the Moon

This paper presents a review of experimental data and theoretical models for distribution of near-surface water resources on Mars and the Moon. Theoretical models of the equilibrium between water vapor on Mars and the freezing subsurface temperatures predict the formation of an "ice table" near the surface at sufficiently high latitudes. Experimental data from orbit confirm this prediction. In addition, the orbital data indicate significant water deposits in some equatorial areas. It is not know if this is ground ice or hydrated minerals. Observations on the Moon are indicative of water deposits in some permanently shaded areas near the poles that act as cold traps. However, the data for the Moon are not as convincing as for Mars. It is highly probable that near-surface water resources will be accessible for in situ resource utilization (ISRU) on Mars, but the case for the Moon is less certain.