Spirit remains healthy and spent much of the week studying a new rock target on "Mitcheltree Ridge" called "Torquas." Scientists are trying to understand what relationship Mitcheltree Ridge has to "Home Plate" -- for example, whether it is an extension of Home Plate or an entirely different rock layer, and whether it has similar composition or morphology.
Torquas is nicknamed after a dried-up seabed covered with moss in the Barsoom science fiction saga by Edgar Rice Burroughs.
Sol-by-sol summary:
In addition to daily observations of atmospheric dust levels and surveys of the sky and ground with the miniature thermal emission spectrometer, Spirit conducted the following activities:
Sol 1141 (March 20, 2007): Spirit acquired panoramic camera images of Torquas, nudged closer to the outcrop, took post-drive images with the navigation camera, acquired images of the sky with the panoramic camera, and watched for dust devils.
Sol 1142: This was a runout sol, or Martian day, meaning the rover completed pre-loaded activities resulting from an only partially successful uplink of new instructions. The uplink was only partially successful because the rover's best-lock frequency was out of range. Runout activities included monitoring atmospheric dust, measuring light looking east and west, imaging the calibration target, and taking thumbnail images of the sky.
Sol 1143: Spirit acquired a 360-degree panorama of images with the navigation camera, stereo microscopic images of Torquas prior to brushing the surface with the rock abrasion tool, and more stereo images after brushing the rock. The rover placed the alpha-particle X-ray spectrometer on the rock and then collected data using the instrument.
Sol 1144 (March 23, 2007): Spirit's first planned task was to acquire panoramic images of Mitcheltree Ridge. Other planned activities included studies of Torquas using the Moessbauer spectrometer, surveys of layered outcrops known as "Zanor," "Banth," "Okar," and "Dor" using the miniature thermal emission spectrometer, and photometric measurements using the panoramic camera.
Odometry:
As of sol 1142 (March 21, 2007), Spirit's total odometry was 7,046 meters (4.38 miles).