Opportunity is on the west rim of Endeavour Crater heading towards 'Marathon Valley,' a putative location for abundant clay minerals.

The rover is headed to a near-term target, a small crater named 'Ulysses.' On Sol 3780 (Sept. 11, 2014), Opportunity drove a little over 33 feet (10 meters) in rocky terrain, requiring the use of Visual Odometry to safely navigate the rock hazards.

On the evening of Sol 3781 (Sept. 12, 2014), an atmospheric argon measurement was collected using the Alpha Particle X-ray Spectrometer.

The next day, the rover drove again, achieving over 66 feet (20 meters) in the difficult terrain.

On the evening of Sol 3783 (Sept. 14, 2014), an 'amnesia' event occurred. This results from the rover being unable to mount its Flash (non-volatile) file storage system during the wake up for Deep Sleep.

A reformat of the Flash file system was performed 10 sols ago and corrected many of the worn out cells in Flash. No science data was lost as a result of the amnesia event and the rover continued normally.

The 98 feet (30-meter) drive on the next sol completed without any issues and the rover performed nominally. The project continues to investigate the Flash-related issues. The rover is otherwise operating in good health.

As of Sol 3785 (Sept. 16, 2014), the solar array energy production was 693 watt-hours with an atmospheric opacity (Tau) of 0.905 and a solar array dust factor of 0.768.

Total odometry is 25.32 miles (40.75 kilometers).