In their fifth year on Mars, NASA’s Spirit and Opportunity exploration rovers have uncovered a ‘life-threatening fact’…at least on Mars: it is very less likely that life on the fourth planet of the Sun was ever possible. And scientists found an explanation to support that theory: the high concentration of minerals, which constitute harsh environment even for the toughest microbes.

The theory doesn’t completely cut the chances of life on Mars, but it pretty much narrows them down to almost nothing. At the February 15 meeting of the American Association for the Advancement of Science in Boston, Dr. Andrew Knoll, member of the rover science team, said: “Life at the Martian surface would have been very challenging for the past 4 billion years. The best hopes for a story of life on Mars are the environments we haven’t studied yet – older one, subsurface ones.”

The conclusion regarding the possibility of life on Mars in an extremely salty environment came after scientists conducted a series of experiments by simulating the Martian conditions: “At first we focused on acidity, because the environment would have been very acidic,” Knoll further said. “Now, we also appreciate the high salinity of the water when it left behind the minerals Opportunity found. This tightens the noose of the possibility of life.”

Researchers are now trying to establish the possibility of life on Mars based on a very essential element in the planet’s history: water. The two rovers that are currently on Mars will soon end their mission, but NASA’s research efforts on Mars are far from being over. The next generation of rover, Phoenix, is expected to reach the “red planet” on May 25.

“Our next missions, Phoenix and Mars Science Laboratory, mark a transition from water to habitability – assessing whether sites where there’s been water have had conditions suited to life,” said Charles Elachi, Director of NASA Jet Propulsion Laboratory in Pasadena. “Where conditions were habitable, later missions may look for evidence of life.”