NASA's long-lived Mars rover Opportunity that beat newcomer sister probe Curiosity to an area containing water-formed clay minerals, has rolled into a region that may be far richer than scientists first realized.
A new study looks at chemicals spotted by a Mars-orbiting spacecraft to conclude that Endeavour Crater, which Opportunity reached in August 2011 after a 1,000-plus day, 13-mile trek across the plains of Meridian, is flush with a variety of clays, which on Earth, form in the presence of water.
Opportunity and an identical rover, Spirit, which is no longer working, landed on opposite sides of Mars in January 2004 to look for signs of past water.
Both found clear evidence that water has played a role in Mars' history, but the chemistry of the liquid was determined to be highly acidic, similar to battery acid, and not very friendly to life as we know it.
Clay minerals point to a different story, one involving a neutral water chemistry - water you could drink, lead rover scientist Steve Squyres, with Cornell University, told reporters at the American Geophysical Union conference in San Francisco this month.