Evidence that Mars was once mild and wet found by Opportunity Rover

On the Opportunity rover's 10th birthday, NASA reveals new clay samples which provide evidence of a Mars that was once wet and mild.

New rock samples collected by NASA’s Mars Exploration Rover Opportunity confirm that the planet was once milder and wetter than it is at present. The discovery gives new hope to those searching for microbial life on the red planet.

Opportunity Deputy Principal Investigator Ray Arvidson, a professor at Washington University in St. Louis wrote, in depth, about the findings and their implications in the Jan. 24 edition of the journal Science.

“These rocks are older than any we examined earlier in the mission, and they reveal more favorable conditions for microbial life than any evidence previously examined by investigations with Opportunity,” said Arvidson.

NASA selected the rocks for examination with the aid of a mineral-mapping instrument on NASA’s Mars Reconnaissance Orbiter (MRO). Samples of a clay mineral known as iron-rich smectite were taken from an area called Matijevic Hill on the rim of the Endeavor Crater, where Opportunity is currently exploring.

NASA researchers believe that the wet conditions needed to produce the iron-rick smectite precede the formation of the Endeavor Crater. If that is the case, it would make the samples more than 4 billion years years old.

“The more we explore Mars, the more interesting it becomes. These latest findings present yet another kind of gift that just happens to coincide with Opportunity’s 10th anniversary on Mars,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program. “We’re finding more places where Mars reveals a warmer and wetter planet in its history. This gives us greater incentive to continue seeking evidence of past life on Mars.”

Opportunity’s mission was expected to last only three months. It is now moving into its 11th year of operation and, according to NASA, has shown little change in health over the last year. At present there is no end in sight for the Opportunity mission.

“Over the past decade, Mars rovers have made the Red Planet our workplace, our neighborhood,” said John Callas, manager of NASA’s Mars Exploration Rover Project, which built and operates Opportunity. “The longevity and the distances driven are remarkable. But even more important are the discoveries that are made and the generation that has been inspired.”

To celebrate the 10th anniversary, NASA has put a gallery of images online at mars.nasa.gov/mer10. Regular updates are also provided on Twitter and Facebook.