Sol 4588, December 20, 2016; Rover Field Report by Larry Crumpler, MER Science Team & New Mexico Museum of Natural History & Science: Not a boring flat terrain, but heroically rugged terrain — Hopefully the brakes are good! For a rover that originally landed 12 years ago on what amounts to a flat parking lot, the current terrain is about as different and rugged as any mountain goat rover could handle. On this sol Opportunity continued to climb up the inner crater wall of Endeavour crater. This view is part of the end-of-drive Navcam panorama from this sol. The view is to the southeast and shows how steep the local gterrain is. Also in the far left you can see the rim and floor of the 22-km diameter Endeavour impact crater wrapping around to the south.
The slopes here exceed 20 degrees and the surface consists of flat outcrops of impact breccias covered with tiny rocks that act like ball bearings. Anyone who has attempted to walk on a 20 degree slope with a covering of fine pebbles on hard outcrop can attest to the difficulty. Opportunity has been operating at these extreme slopes for several months. But going down hill is one thing, And going back up hill is another entirely. This is a front hazcam view looking up slope at the end of…. [More at link]