As a rule, the truly large deposits of ice on Mars are at the poles... right? No. Researchers using the Mars Reconnaissance Orbiter's ground-penetrating radar have discovered that the planet's Utopia Planitia basin is hiding a thick (260 to 560 feet) ice sheet larger than the state of New Mexico. It's at least 50 percent pure, too. Observers had long suspected that the area had water thanks to surface cracking and depressions, but the previous explorer, the Mars Odyssey spacecraft, couldn't study much deeper than the surface.
Scientists tell the New York Times that the sheet likely accumulated as part of a Martian ice age and was buried before it could melt into a lake or evaporate into space.
The findings are important for our understanding of Mars' past. However, they could also have a very practical role in the future. Spacefarers could establish a long-term settlement in a more convenient place than the poles while knowing that they'd still have steady local supplies of drinking water and rocket fuel. That, in turn, could reduce the supplies that astronauts have to carry to the Red Planet and make Mars exploration that much more realistic.