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.