About three months after Spirit sent her last communiqué, in June 2010, presumably while the rover was still in hibernation, Richard Morris and MER Science Team colleagues announced that Comanche (the big brown outcrop) is harboring magnesium iron carbonate, and a lot of it. they theorized that it could have been produced by a hydrothermal system. It was a discovery MER PI Steve Squyres called “one of the top five findings of the entire mission.”
Opportunity pressed on toward Endeavour. On May 19, 2010, she surpassed Viking 1 and became the longest-lived robot on the surface of Mars, with 2,245 sols and counting. And then, a little more than a year later on August 9, 2011, “Little Miss Perfect” reached Endeavour. It was a record-setting, mind-bending, rover-driving-wow of an achievement.
The rover made “land’ at Cape York, a remnant of Endeavour’s western rim, at an area with outcrop, a tiny crater, and a view inside the crater that the team christened Spirit Point. From there, Opportunity began a new mission, to travel farther back in Martian time than any other ‘bot ever to the Noachian Period some 3 to 4 billion years ago. It was during this epoch Endeavour was created, a time when planetary scientists generally believe Mars was more like Earth, with water flowing above and under ground, rivers winding, lakes pooling, maybe even an ocean, hot springs bubbling and volcanoes erupting.
“We had been anticipating it for so long and it took us so long to get there and we had so many challenges,” remembered Rover Planner Ashley Stroupe. “We never knew if we were really going to make it. Then, when we got that first view down into the crater – that for me is one of the absolute highlights from driving Opportunity. The only thing that will beat that day, that sol for me is if we get down to Iazu [Crater].”
For Arvidson the best moment was about a year away, waiting on a hill that was just on the other side of Cape York. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which searches for signs of past and present water on Mars from its perch on MRO, detected phyllosilicates, ancient clay minerals and a sure sign of past water, in the Cape York area. It’s why Opportunity and the team were at Cape York.
As a member of the CRISM team, Arvidson managed to acquire hyperspectral data that homed in on this particular hill as “the sweet spot.” The site was promptly named for Jake Matijevic, a brilliant and beloved member of the original Spirit and Opportunity development team and a former Chief of MER Rover Engineering. Jake had passed away unexpectedly in August 2012, the same month Opportunity was driving along the inner part of Cape York and nearing the base of the hill.
“I remember calling Steve and saying, ‘This is it, man. We’ve got to turn right and go uphill,’” Arvidson recalled.
Squyres agreed. The two handily convinced the last hold-outs on the science team during a SOWG meeting and Opportunity took that right turn. To say it was a good call would be a grand understatement. Turned out, Matijevic Hill is a science jackpot. The robot field geologist not only found evidence for ancient clay minerals but uncovered what the scientists believe is the most ancient Martian strata or ground ever discovered on the surface, now known as Matijevic Formation.
“To me that was the most exciting moment,” said Arvidson. “It was the confluence of a number of analyses that led to that right hand turn, including the CRISM multispectral map and what we could see with the Navcam looking uphill.”
