Opportunity is inside 'Marathon Valley,' up on north-facing slopes for improved solar array energy production.

The rover is conducting an in-situ (contact) science campaign on the surface target 'Pvt. John Potts' (informally named for members of the Lewis and Clark expedition).

Previously, Opportunity had performed two successful Rock Abrasion Tool (RAT) grinds on this target totaling over 1 millimeter of grind depth.

On Sol 4257 (Jan. 14, 2016), the rover used the RAT again to grind another millimeter. With the grinding complete, the RAT brushed the target on Sol 4259 (Jan. 16, 2016), sweeping away the grind tailings.

Then, a Microscopic Imager (MI) mosaic was collected followed with the placement of the Alpha Particle X-ray Spectrometer (APXS) inside the ground target.

Also during this time, the rover continued collecting color Panoramic (Pancam) images of 'Knudsen Ridge' to form a large panorama mosaic of the valley ridge.

With the in-situ work now complete on this target, on Sol 4262 (Jan. 19, 2016), the rover bumped only 2 inches (5 centimeters) to position for another target for in-situ investigation.

As of Sol 4262 (Jan. 19, 2016), the solar array energy production was 454 watt-hours with an atmospheric opacity (Tau) of 0.471 and a solar array dust factor of 0.670.

Total odometry is 26.50 miles (42.65 kilometers), more than a marathon.