Opportunity has not moved (intentionally or otherwise) since its stabilizing maneuver on sol 158. The rover has been using the instruments on its arm and mast to study the rocks at its current location, which is in the sixth layer encountered on the way into “Endurance Crater.”

Opportunity remains in excellent health. Deep sleep has been invoked every other night to save energy; the miniature thermal emission spectrometer continues to operate nominally despite temperatures as low as -53 degrees Celsius (-127 degrees Fahrenheit) on some nights.

Opportunity is due for a set of “corrective lenses” (new hazard-avoidance camera models) after the trial run of new camera models is complete on Opportunity’s twin rover, Spirit. In the meantime, the rover team has been using microscopic imager mosaics to locate targets when the hazard-avoidance camera-based targeting is not sufficient.

The mechanical team is investigating an anomaly involving the door on the alpha particle X-ray spectrometer. The spectrometer has two contact switches; one that indicates its doors are open, another that indicates it is fully in contact with its target.

For the purpose of opening the alpha particle X-ray spectrometer doors on sol 161, engineers placed the spectrometer on the compositional calibration target, a rock disc with a known composition that is located on the underbelly of Opportunity.

It is used to calibrate the Moessbauer instrument periodically. The team expected both contact switches to trip on that move; only the in-contact switch tripped.

The next sol, when the spectrometer was removed from its rock target, a front hazard-avoidance camera image indicated that the doors were fully open. A subsequent move to close the doors resulted in only partial closure.

The team tried again to open, then close the doors and was successful, with the doors fully open, then fully closed during that maneuver. The door-open contact switch, however, once again did not trigger as expected during that maneuver.

Since the team is still able to safely open and close the alpha particle X-ray spectrometer doors, full use of the instrument is not compromised.