If you ask most people is microbes could survive on Mars, they would answer  "no".  Yet recent evidence from the rover Curiosity suggest that life (microbes) may have existed billions of years ago, when analysis of rock drillings showed traces of some of the most fundamental elements for life (sulfur, hydrogen, carbon, oxygen, nitrogen, etc), in addition to water covering the planet's surface. 

          NASA scientists recently stated that Mars may have supported life billions of years ago, after new evidence from the rover Curiosity was collected.  Essentially a small, self-operating science laboratory, the rover landed in a 96-mile crater named Gale and began sampling rocks and the planet’s soil-like surface.  To the surprise of many, analysis of the samples revealed the presence of several fundamental elements of life like hydrogen, oxygen, sulfur, nitrogen, phosphorus, and carbon.  In addition, the rock drillings showed that minerals like sulfates and sulfides – a potential energy source for primitive microbes – were also present.  However, the most exciting discovery was that of clays.  This type of soil is not only a prime place to look for organics (a prerequisite for life), but can only be formed by neutral waters.  Thus, its presence suggests that water had to be flowing on the planet’s surface at some time in the past.

            The reason water, and life for that matter, no longer exist on Mars is because billions of years ago the planet experienced a change.  Being a lot less dense than Earth, Mars was unable to sustain its atmosphere, and as a result its core began to cool, volcanic eruptions ceased, and the surface water either froze or evaporated into space.  While these findings are exciting, there are some things to consider.  It is possible that the organic minerals and elements found on Mars are contaminants from Earth, or were potentially brought there by a meteor crash landing to the surface.