Sol 166's tasks for Spirit included imaging of possible traverse paths inside "Endurance Crater," then the start of a long period of data collection by the M�ssbauer spectrometer on a target called "Dahlia." All went as planned.
Sol 167 saw completion of the M�ssbauer spectrometer's long integration at Dahlia, acquisition of some microscopic imager pictures, and placement of the alpha particle X-ray spectrometer on the capture magnet, which is one of the two magnets on the front of the rover deck. In the early morning hours of sol 168, the alpha particle X-ray spectrometer collected data at this magnet. The composition of material sticking to the magnet is what interests scientists.
On sol 168, the rover lifted the alpha particle X-ray spectrometer off the capture magnet and replaced it with the M�ssbauer spectrometer for the start of a long integration with that instrument. These complementary measurements of the material on the capture magnet should provide insight into the composition and magnetic properties of the dust around the rover. Remote-sensing activities were also performed.
On sol 169, the rover drove deeper into the crater. A judgment had been made that the terrain in front of the rover would be no more difficult to traverse than terrain the rover had already crossed. Further, the science team was very interested in some geologic features about 3 to 4 meters (about 10 to 13 feet) down the slope, next to and including a rock called "Knossos." The rover stowed its arm and trundled down the nearly 30-degree slope, arriving on a more-level area exactly where engineers intended. The rover is now below the steepest part of the inner slope in this part of the crater.
Up to this point, Opportunity had not been commanded to take any images during an ultra-high-frequency (UHF) relay session with orbiting spacecraft. Testing prior to launch suggested that there could be electromagnetic interference that would degrade the telemetry link, so operations had carefully kept those activities separate. However, time could be used more efficiently if the rover could simultaneously take images and communicate. As an experiment, the rover was commanded to take navigation camera and panoramic camera images while transmitting on sols 167 and 168, respectively. The quality of data sent during use of the navigation camera has been analyzed, and there seems to have been no ill effect. Data is still being analyzed from the transmission during use of the panoramic camera. The UHF relay session returned the expected amount of data. In both cases, no degradation of images was expected or seen. Based on this experiment, the engineering team will consider lifting the restriction against imaging during a UHF session.