If Opportunity’s bouts of amnesia should become persistent, “then it becomes more annoying,” said Nelson. The amnesia, however, is enough of a concern that there is talk about bringing in a bright young computer science intern onboard and “turning him/her loose” to see what might be found.

Until any new news turns up on this front, the plan is for Opportunity “to continue happily on six banks of flash, and monitor her if she has any more amnesia,” said Sosland.

A little amnesia though wasn’t about to stop this rover. On Sol 3970 (March 26, 2015), Opportunity brushed Athens with her RAT, took the pictures for an MI stereo of Athens, and then placed her APXS on the rock to determine its chemical make-up. The robot took more Pancam images of Athens and another nearby outcrop Plataea on the following sol, 3971 (March 27, 2015), and then bumped to Thessaloniki, another outcrop in the bright area in the apron around Spirit of St. Louis Crater. That’s where the rover would spend the rest of the March.

While the MER scientists are in the midst of reviewing and analyzing the data coming in from the bright rock outcrops, Arvidson ventured an early, working hypothesis: “This looks to be an area that is probably a leach zone, where hot fluids came through and removed the iron and other materials that make things dark,” he said.

As the calendar turns from March to April, the plan ahead is for Opportunity to complete her work on the bright outcrops. “We saw in the MIs some discontinuous dark coatings, reminiscent of things we saw at Matijevic Hill,” said Squyres. “I'm not saying it's the same thing, because we don't know yet, but the discontinuous dark coatings we’re seeing, to my eye, look similar to what we saw on Matijevic Hill. They are thinner, like little flakes of stuff, but the coatings are there.”

The coatings Opportunity found on rocks on Matijevic Hill, you may remember, turned out to be remnants of clay minerals that once long, long ago might have been a haven for the emergence of lifeforms, the phyllosilicates that the mission was looking for.

Rather than drive away, the MER team decided to have Opportunity do some more APXS work on these bright outcrops, with several off-set measurements to see if they can disentangle the composition of the coating from the composition of the underlying rock. “We were drawn to this part of Mars by an infrared signature from orbit that looks similar in many respects to what drew us originally to Matijevic Hill, so we are naturally going to be looking for Matijevic Hill-like things,” Squyres said. “But we haven't seen any newberries and it would be really, really easy to get fooled here. We’re going slow and making measurements and going to try and figure it out.”

Once her work in this area is done, Opportunity, if everything goes as planned, will drive the some 30 meters into Spirit of St. Louis Crater. “This crater is so enigmatic,” said Arvidson. “It’s very shallow and has this crazy mound of rocks, Lindbergh Mound, which is not even in the center but displaced to the east. We’ll look at some of the blocks that have rolled off of it and try to answer what exactly is going on. Do these rocks represent yet another rock type? Are they blue rock types, or like Ulysses rocks? They we’ll explore the crater to try to determine if it was formed by a low velocity impact from ejecta – or whether it’s volcanic – and whether it is something else. The ideas are all over the place. So we need to make some measurements.”

Then at long last, Opportunity will drive another 100-150 meters and into the Marathon Valley proper, where MER scientists know there are discoveries and Martian riches and mysteries awaiting their arrival. The rover is ready, despite increasing dust in the atmosphere.

At month’s end, Opportunity was producing 549 watt-hours of power, plenty of energy to drive and work. Although the Tau rose to 0.976, her solar array dust factor was hovering around 0.745. “Summer is a dusty time of the Martian year and there have been some regional storms to the west of the rover site,” said Nelson. “These pose no threat to the rover – they're on the order of 1000 km away – but they do loft dust into the atmosphere which is why we're seeing more elevated Tau values. Even so, this is expected and consistent with prior Martian years.”