The Mars rover Opportunity is in the news again. It's mission was supposed to last 90 days. It has been working for 7 years. And while it's companion rover Spirit finally gave up the ghost earlier this year, the "little Rover that could" is still making breakthrough discoveries.

IBT:

Mars Rover Opportunity got a second wind and has discovered a rock that is "different from any rock ever seen on Mars," said Steve Squyres, principal investigator for Opportunity at Cornell University.

Three years ago, Opportunity climbed out of the Victoria crater on Mars, which it had spent two years studying. Three weeks ago, it arrived at the rim of the Endeavour crater.

"This is like having a brand new landing site for our veteran rover," said Dave Lavery, program executive for NASA's Mars Exploration Rovers.

At Endeavour's rim, Opportunity discovered the unprecedented rock, which is about the size of a footstool. It was excavated by an impact that formed a crater the size of a tennis court. The rock has a composition similar to some volcanic rocks but contains more zinc and bromine than typically seen.

The diversity of fragments seen on the rock "could be a prelude to other minerals Opportunity might find at Endeavour," stated NASA.

Furthermore, observations made by Opportunity at the crater's rim suggest that rocks there date from early in Martian history and "include clay minerals that form in less-acidic wet conditions, possibly more favorable for life."

Since landing in 2004, Opportunity has crawled in and out of a huge crater and traversed more than 20 miles of the Martian surface. It might not seem impressive but when you consider the obstacles in its path and the fact that it takes several minutes for instructions relayed from earth to reach ther rover, one can see it is an extremely laborious process to move the rover in the first place. (Future rovers will be much "smarter" and be able to avoid many obstacles without instructions from earth.)

The crater Endeavour promises to be a treasure trove of early Martian rock formation:

At Endeavour, scientists expect to see much older rocks and terrains than those examined by Opportunity during its first seven years on Mars. Endeavour became a tantalizing destination after NASA's Mars Reconnaissance Orbiter detected clay minerals that may have formed in an early warmer and wetter period.

"We're soon going to get the opportunity to sample a rock type the rovers haven't seen yet," said Matthew Golombek, Mars Exploration Rover science team member, at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Clay minerals form in wet conditions so we may learn about a potentially habitable environment that appears to have been very different from those responsible for the rocks comprising the plains."

Next up for Mars exploration, the much more sophisticated rover dubbed Curiosity with a scheduled launch sometime between November 25 and December 18. According to NASA,

During a two-year mission on the Red Planet, the rover will investigate whether a selected area of Mars has offered environmental conditions favorable for microbial life and for preserving evidence about life.

There is also a Mars orbiter project on the books that would investigate the upper atmosphere of the red planet. But that project may be subject to delays or elimination due to NASA budget cuts.