Schopf says orbital mapping also shows similar mineral deposits on Mars. "We now know that this is a good place to look for evidence of fossil life on Mars, but I think that also you might see clumps of organic material and that would be a real good finding on Mars because if we can find the organic matter, then we have a real reason to think that there might once have been life there."

NASA/JPL-CaltechNASA's Mars Exploration Rover Opportunity climbed out of "Victoria Crater" following the tracks it had made when it descended into the 800-meter-diameter (half-mile-diameter) bowl nearly a year earlier.

Life on Mars

As luck would have it, the Mars rover, named Opportunity, landed on a field of gypsum - or calcium sulfate six years ago.

NASA's Steve Squires says Mars rocks and soil could yield valuable clues to ancient forms of life. "We know there are iron sulfates, magnesium sulfates and calcium sulfates. Gypsum is a calcium sulfate. All of those are present at the Opportunity landing site."

UCLA professor Bill Schopf is anxious to analyze those Martian sulfates for signs of life. "I think that if we had the rocks back tomorrow morning, and I had them in my lab, I think we could solve this problem.

Squires says the discovery of water and organic materials - the building blocks of life as we know it on Earth - will be top priorities on NASA's future deep-space missions.