Opportunity is moving south along the west rim of Endeavour Crater heading towards 'Marathon Valley,' a notch observed from orbit to have an abundant clay mineral signature.

On Sol 3739 (July 31, 2014), the rover made an approach to a surface target of interest with a 26-feet (8-meter) drive. At the end of the sol, Opportunity collected some Panoramic Camera (Pancam) imagery and performed an atmospheric argon measurement with the Alpha Particle X-ray Spectrometer (APXS).

On Sol 3741 (Aug. 2, 2014), the rover began two sols of in-situ (contact) science using the robotic arm instruments.

On the first sol Opportunity collected a Microscopic Imager (MI) mosaic of the target 'Fairweather,' and then placed the APXS for a multi-hour integration. On the next sol, the observations were repeated on a second, offset target.

With the in-situ work complete, the rover headed south again on Sol 3744 (Aug. 5, 2014), driving over 282 feet (86 meters). The drive was followed with the usual post-drive Navigation Camera (Navcam) and Pancam panoramas to support the next drive.

As of Sol 3744 (Aug. 5, 2014), the solar array energy production was 686 watt-hours with an atmospheric opacity (Tau) of 0.872 and a solar array dust factor of 0.802.

Total odometry is 25.09 miles (40.38 kilometers).