Antarctica is an environment of extremes that has provided NASA with several avenues to explore our origins, from the formation of planets to the genesis and distribution of life. For example, although the arid, extremely cold ice-free regions of the continent appear barren, they actually harbor life in habitats analogous to those that could have supported life on ancient Mars. Because early Mars had liquid water, life could have begun there during the same time that life began on Earth. Antarctica offers Earth's best analog environment to ancient Martian environment, specifically before the planet lost most of its atmosphere.
In Antarctica, the Transantarctic Mountains block ice flowing from the east Antarctic plateau, forming the ice-free McMurdo Dry Valleys, a region with a mean annual temperature of -20°C. Although temperatures here seldom rise above freezing, microbial life has been found beneath perennially ice-covered lakes and inside porous sandstone rocks. In places never before suspected of harboring life, microorganisms are thriving wherever there is liquid water, even if only for a few hours a year. Research into these microbial habitats has expanded the known environmental limits for life on Earth and enhanced our understanding, which in turn will enable us to develop better strategies for the search for evidence of life on Mars, whether extinct or extant.