We know Mars has water ice in its polar regions, but astronauts (and their solar-powered equipment!) would much rather experience life closer to Mars’ equator. As NASA looks toward landing humans on the red planet, the Planetary Science Institute (PSI) is mapping where water should and shouldn’t be found and using statistics to quantify its certainty. Two new papers, led by PSI’s Hanna Sizemore and Samuel Courville, highlight new global maps of subsurface water ice and identify the missions and tools needed to increase the certainty of the maps.