Opportunity is on the west rim of Endeavour Crater near "Marathon Valley," a putative location for abundant clay minerals now only about 492 feet (150 meters) away.

The project is preparing to mask off the troubled Bank 7 sector of the Flash file system with a new version of the flight software (FSW). The preparations for the FSW load and build were to begin with the 3-sol plan on Sol 3938 (Feb. 20, 2015).

However, bad weather and a complex power outage in Canberra, Australia prevented the plans from being sent. The rover was allowed to safely execute its onboard runout plan for the weekend.

On Sol 3941 (Feb. 23, 2015), preparations were restarted for the FSW build. Remote sensing observations of Marathon Valley were also performed.

On Sol 3942 (Feb. 24, 2015), the FSW patch was uploaded and the new FSW was successfully built and saved onboard. On the next sol, Opportunity successfully booted onto the new version of FSW and is running without error.

Further remote observations of Marathon Valley with the Panoramic Camera (Pancam) and the collection of an atmospheric argon measurement with the Alpha Particle X-ray Spectrometer were also commanded.

The plan ahead is to allow a few days to confirm all aspects of the new FSW before performing the reformat of the Flash file system with the new software.

As of Sol 3943 (Feb. 26, 2015), the solar array energy production was 559 watt-hours with an atmospheric opacity (Tau) of 0.734 and a solar array dust factor of 0.674.

Total odometry is 26.13 miles (42.05 kilometers).