Opportunity and her team were hoping the contact they spied at Copper Cliff represented the definitive boundary between Whitewater Lake and the Shoemaker Formation. "But that is not what we've found here," said Squyres. "What we found are busted up rocks that have a number of Whitewater Lake-type characteristics, including newberries, and a somewhat different chemistry from Whitewater Lake, and we're still puzzling over it," he continued. "But we have not found a simple contact between Whitewater Lake and Shoemaker Formation impact breccias."

Opportunity moved again last week to spend the long New Year's weekend at a small bright outcrop just above Copper Cliff, called Vermilion, which the scientists thought could be sought-after contact between the Shoemaker Formation breccias and the Whitewater Lake rocks. It wasn't, said Arvidson.

As 2012 faded to history, Opportunity's odometer read 35,438.37 meters (35.43 kilometers or 22.02 miles). It was producing 542 watt-hours of power, and reporting a Tau of 0.961 but an improved solar array dust factor of 0.633. Despite the dusty skies overhead, the robot field geologist's future looks as bright as it possibly could for the veteran rover.

Once Opportunity's work at Vermilion is finished, the science team will choose the next target for scientific inspection. "We have lots of images from the walk-about and we will try to find the best places to do those things, but we have not chosen all of them yet," said Squyres.

If all goes as planned however, Opportunity will be driving on soon – to its next destination, as well as its next anniversary.

Looking Back on 2012

Looking back, the MER scientists and engineers agree that 2012 was, all things considered, a very, very good year for Opportunity.

"It's been one of the best years we've had. We're looking at very ancient, clay-bearing rocks for the first time ever on Mars, for the first time ever with this rover," reflected Squyres. "We're still working out what it means, but on Maitjevic Hill, we have arrived at and are beginning to dig into one of the most significant and interesting geologic puzzles of the whole mission."

"It was really the year of the first detailed characterization of a real stratigraphic section of ancient Noachian crust," added Arvidson. "Nothing will beat landing in Eagle Crater and characterizing the Burns Formation. But I would rank 2012 as second only to that excitement associated with the first set of measurements at Eagle Crater when we realized we had an important discovery on our hands."

It was however, the year they had to give up on the Mössbauer spectrometer, because its radioactive source was just too weak to make any meaningful measurements, recalled Callas. "But the cameras and APXS are in great shape. The RAT was designed to do three RATings in the first three months, and it still has teeth available to grind and does a beautiful job grinding, like a senior citizen who still doesn't have to have dentures yet, and we haven't had any real degradation on the vehicle. Each year, the thing that stands out is the fact that this rover is another year older and yet it keeps going.

The real downsides in 2012 came with the human losses, the passings of Martian pioneers Jake Matijevic and Ray Bradbury.

Perhaps, if one believes that robots can dream of sheep at night, it is for them, the other team members who died before them, and her twin, Spirit, that Opportunity finds a way against all odds to rove ever onward in her exploration of Meridiani Planum, Mars.