April 11, 2018: Opportunity Presses On in Perseverance, Pace Picks Up: In the west rim of Endeavour Crater, Opportunity continued her exploration of Perseverance Valley in March – humankind’s first study of a carved channel in an ancient crater on the Red Planet – while scientists on Earth presented their latest findings from the robot’s returns at a prominent science conference and Mars Exploration Rovers (MER) officials worked on the plan to keep the mission trekking through 2019.
The robot field geologist spent most of the month checking out a couple of new outcrop targets at the “nose” or “upstream” end of an elongated “island” that separates two pathways in the Perseverance Valley’s anastomosing – or branching – structure. Opportunity even scraped into one of the targets with her Rock Abrasion Tool (RAT), her first grind into a rock in 321 sols or Martian days.(…)
(…) That heading change put Opportunity on track to her next destination, a long linear group of rocks distinguished by holes, vesicular rocks as the geologists call them, located in the southern margin of the south fork. The scientists had had this site, named San Juan Pueblo, in their sights for a while now. It may be harboring the first volcanic rocks that this rover has ever encountered.
By the end of March, Opportunity was at the vesicular rocks site, which, actually, defines the southern border of the south trough, and had just begun her investigation at San Juan Pueblo. And the plot driving the Story of Perseverance thickened.
“There are highly unusual textures here,” said Ray Arvidson, MER Deputy Principal Investigator, of Washington University St. Louis (WUSTL). “Are the voids [holes in the rocks] actual vesicles that are due to volcanic degassing from an igneous rock?” he asked. “Are they impact melt rocks that have degassed leaving voids or vesicles? And why are they aligned at the trough border?” he wondered. [More at link]