Sol 4633, February 6, 2017; Rover Field Report by Larry Crumpler, MER Science Team & New Mexico Museum of Natural History & Science: Several sols ago Opportunity made it up and past the steepest section of its climb out of Endeavour crater. Slopes that were exceeding 20 degrees or locally more, went to less than 20 degrees. Then in the last couple of drives slopes have dropped a little more.
This is a big relief because Opportunity had been exploring deep inside the Endeavour crater rim where the slopes were approaching the angle of repose of loose materials. It was not entirely certain that it could drive out. There was one place were drives were just digging in because the slopes were too steep. These are slopes that you would have difficulty standing upright on.
The view southwest now and ahead is of the crater rim. Opportunity is about to do the impossible and escape from inside a 22 km impact crater. And the things we just saw down in there have never been seen before. This is natural history exploration at its finest. [More at link]