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.
Opportunity also spotted what looks like a sedimentary rock that's been cut and filled with veins of material possibly delivered by water.
The wealth of information observed by the aged rover is a gift to NASA; Opportunity has already worked 30 times longer than originally planned.
Lavery attributed its longevity and hardiness to well-built hardware that lasts.
However, the rover could lose a critical component on an essential rover system, and the mission would be over, warned John Callas, project manager for Opportunity at NASA.