Opportunity's health is excellent. Solar exposure continues to be very good. Opportunity spent its first night inside "Endurance Crater" on sol134. To date, the rover has spent 130 sols in the crater, grinding 21 targets with the rock abrasion tool, performing 62 integrations with the Mossbauer spectrometer and 33 with the alpha particle X-ray spectrometer, and taking 115 observations with the miniature thermal emission spectrometer. Opportunity finally completed observations on the rock "Wopmay," and is ready to begin its trek towards "Burns Cliff" on the way to exiting Endurance Crater.
On sol 258, Opportunity examined three targets ("Otter," "Jenny," and "Hiller") on Wopmay with its microscopic imager. Each of the observations was designed to produce a mosaic. They relied on touching the instrument's contact sensor to the uneven surface of Wopmay for each quadrant of each mosaic to ensure appropriate standoff distances for good focus.
Sols 259 through 261 were designed as a single three-sol weekend plan. During the morning of sol 259, arm operations continued with two more microscopic imager mosaics of the targets "Jet Ranger 2" and "Twin Otter." In the early afternoon, Opportunity placed its alpha particle X-ray spectrometer in a hover position approximately 1 centimeter (0.4 inches) above Otter. After a couple of naps and miniature thermal emission spectrometer observations, the rover went into deep sleep until the next morning.
The first part of a reading with the alpha particle X-ray spectrometer over Otter was performed for three hours in the morning of sol 260. During the same period, the rover made navigation camera, panoramic camera, and miniature thermal emission spectrometer cloud observations, then snapped images with the navigation and panoramic cameras in the drive direction. While performing an atmospheric observation with the panoramic camera, Opportunity collected extra images of the sky close to the Sun to allow observations of the dust accumulation on the camera's window.
In the early morning of sol 261, the reading with the alpha particle X-ray spectrometer resumed, continuing until about 11 a.m. local solar time and producing excellent spectra despite the standoff position of the sensor. Opportunity then collected Mossbauer data over Otter for another three hours. Several remote science observations were made over the course of the sol, including photometric measurements with the panoramic camera and targeted observations of Wopmay with the miniature thermal emission spectrometer and the panoramic camera observations.
On the morning of sol 262, Opportunity took a third photometric measurement and used the panoramic camera to study Wopmay, concluding the weekend plan. In the early afternoon, the rover made a final microscopic image of the target "Hercules" on Wopmay, then backed away as part of a plan to re-approach the back side of Wopmay for possible additional measurements. Navigation camera imagery of the back of Wopmay was collected in the afternoon, followed by extensive panoramic camera imaging the next morning. Unfortunately, due to slippage during the traverse, Opportunity didn't reach its desired vantage point, and the target was not in view.
For sol 263, a decision was made to delete the panoramic camera imagery without downlinking it, since on board memory was tight and we already have complete coverage of the part of Wopmay captured. The new plan was to continue the rover's drive toward the back of Wopmay, and repeat the imaging observations attempted in the sol 262 plan. But as Opportunity drove toward Wopmay, it encountered a hidden obstacle: a rock buried under the sand that resulted in 100 percent slip for a good part of the traverse. Once the rover was clear of the rock, it continued from a point much closer to Wopmay than anticipated. Rover planners estimated that, at the end of the traverse, Opportunity was within 30 centimeters (just under one foot) of Wopmay, uncomfortably close!
On sol 264, which ended on Oct 21, Opportunity backed away from Wopmay. The planned drive was 2.5 meters (8.2 feet) but the actual drive was2.57 meters (8.4 feet). Opportunity is now in position to begin its drive toward Burns Cliff.
Total odometry after sol 264 is 1,638.57 meters (1.0181 mile).