Opportunity is exploring the south side of 'Marathon Valley' located on the rim of Endeavour crater.

The objective is to identify specific outcrops for evidence of clay minerals, so Opportunity is conducting a mini-'walkabout' in regions that show evidence for clay minerals seen from orbit.

The plan is to quickly survey a large region with imagery and then identify surface targets of interest for further in-situ (contact) investigation.

At each drive location on the walkabout, the rover collects extensive Navigation Camera (Navcam) and Panoramic Camera (Pancam) panoramas plus targeted multi-filter (color) Pancam panoramas.

Energy levels have been very good, so the rover was able to stay up late and collect an atmospheric argon measurement with the Alpha Particle X-ray Spectrometer (APXS) on Sol 4338 (April 6, 2016), after spending the day collecting a multi-frame Pancam panorama.

The previous few drives had indicated an elevation in the right-front wheel current. Some of that is explained by the steep terrain the rover is climbing.

The team sequenced a set of 'cleat cams' (sub-framed Hazardous Camera images) of the front wheels on Sol 4339 (April 7, 2016), to make sure there were no small rocks that might be fouling the wheels. The wheels were found to be clear of any rocks.

On Sol 4340 (April 8, 2016), a set of Microscopic Imager (MI) sky flats (calibration images) were collected using the robotic arm to point the MI up at the diffuse sky. More Pancam and Navcam panoramic imaging was collected at this location.

On the next sol, Opportunity drove about 45 feet (13.7 meters) to the southwest to set up for the next imagining station. Over the next two sols the rover collected extensive Pancam and Navcam imagery.

As of Sol 4343 (April 11, 2016), the solar array energy production is 617 watt-hours with an atmospheric opacity (Tau) of 0.459 and a solar array dust factor of 0.785.

Total odometry is 26.58 miles (42.78 kilometers), more than a marathon.