Opportunity is on the west rim of Endeavour Crater near the entrance of "Marathon Valley," a putative location for abundant clay minerals.

The rover is positioned on a light-toned outcrop next to the feature called "The Spirit of St. Louis" crater. The rover is continuing a campaign to investigate surface targets in this light-toned outcrop.

On Sol 3977 (April 1, 2015), the rover began two sols of Alpha Particle X-ray Spectrometer (APXS) measurements with offset placements between sols. On Sol 3979 (April 3, 2015), the rover bumped to a new surface target, moving almost 20 feet (6 meters).

For the next two evenings, atmospheric argon was measured using the APXS.

Additional in-situ (contact) science with the robotic arm instruments was planned for Sol 3982 (April 7, 2015), but a DSN problem prevented the sequence plan from being transmitted to the rover.

Opportunity instead executed on-board run-out sequences. The missed plan will be repeated in the next uplink planning opportunity.

Two more amnesia events occurred in the evenings of Sols 3979 and 3980 (April 3 and April 5, 2015). Both events were benign with no loss of science data.

As of Sol 3982 (April 7, 2015), the solar array energy production was 559 watt-hours with an atmospheric opacity (Tau) of 0971 and a solar array dust factor of 0.732.

Total odometry is 26.24 miles (42.24 kilometers).