Alien Probe: Mars Lander Seeks Microbe Colonies

The mission's recent confirmations of water ice in the soil and water vapor in the air have led the NASA scientists to reason that a certain kind of water, not quite liquid, but not frozen either, is likely to reside in the Martian soil. Thin films of these water molecules could act as tiny oases for microbial life on the otherwise arid planet.

"They are the most likely habitat that we're going to get to in the foreseeable future," said NASA Ames Research Center's Aaron Zent, the lead scientist for the probe being used to look for unfrozen water. 

The prospect of unfrozen water in subzero temperatures was raised by observations in terrestrial permafrost regions that enough water can exist under those conditions to support life.

Back when the Phoenix was preparing to land, Edward Young, an astrobiologist at UCLA, explained how liquid water could develop in subzero temperatures.

"You can get water that's liquid because of the pressures along [soil] grain boundaries," Young told Wired.com. "It's sort of like when an ice skater puts their blade against the ice. It's a pressure effect."