Over the last few sols, Spirit struggled mightily to reach a rock outcrop called "Clovis," overcoming the challenge of rough, steep terrain and subsequent backsliding. The site is near the crest of the "West Spur" of "Columbia Hills."
On sol 205, Spirit attempted to reach Clovis by climbing out of the sandy hollow in which it was sitting. Unfortunately, on a slope of more than 20 degrees, slippage caused Spirit to dance around the outcrop. The drive was finally cut off by a time-of-day limit on rover mobility.
The plan for sol 206 was designed to accommodate up to a 50 percent slip and still reach the outcrop target. However, due to challenging terrain near Clovis, Spirit again did not end up exactly where scientists and engineers wanted it to go. For part of its traverse, Spirit slipped about 125 percent, actually losing ground in its attempt to move uphill.
Late in the sol, internal software experienced a timing problem in which two instrument-related commands were given at nearly the same time, temporarily precluding further operation of the miniature thermal emission spectrometer and camera mast on Spirit.
Sol 207 became a recovery sol. While the timing issue was being analyzed, engineers decided not to use the mast, panoramic cameras, navigation cameras, M�ssbauer spectrometer, alpha particle X-ray spectrometer, or the miniature thermal emission spectrometer. On the bright side, since the problem did not affect communications, a communications experiment with the European Space Agency's Mars Express orbiter was successfully conducted in the early morning hours of sol 208.
By sol 208, which ended on Aug. 3, Pacific Time, the mast had been declared usable. Operators commanded Spirit to drive 7.5 meters (25.6 feet) to Clovis, using a route avoiding the steepest terrain that had created problems for the rover in earlier sols.
Spirit is examining Clovis. This outcrop will likely be the subject of Spirit's most intensive investigation to date.