The whole point of Mars for NASA has been the search for life. Since the initiation of unmanned missions on Mars NASA has been working to find such signs as primitive amino acids, water ice or liquid water, and small microbes that would be the first indications of the potential or existence of more advanced life on the planet currently or in the past. NASA considers the discovery of liquid water the most important event in their studies of Mars.
Among our discoveries about Mars, one stands out above all others: the possible presence of liquid water on Mars, either in its ancient past or preserved in the subsurface today. Water is key because almost everywhere we find water on Earth, we find life. If Mars once had liquid water, or still does today, it's compelling to ask whether any microscopic life forms could have developed on its surface. Is there any evidence of life in the planet's past? If so, could any of these tiny living creatures still exist today? Imagine how exciting it would be to answer, "Yes!!"
NASA's overall timeline for the search for life on the Red Planet.
The whole idea of NASA’s plan is to seek signs of life. They hope to one day find distinct evidence of contemporary primitive life on the planet, remnants of one time when Mars was far wetter and warmer than it is today, back when it had a magnetic field. The hope, eventually, is that Mars may serve as a probable location for people to then colonize.
Learn more about their missions: