Mars Exploration Rover Update - January 25, 2006

SPIRIT UPDATE: Spirit Completes Studies of ‘Arad,’ Moves On -
sol 723-729, Jan 25, 2006:

Spirit is healthy and continues to pursue the short-term goal of
to “Home Plate.” Results from scientific instruments on the rover’s
robotic arm indicate that the white soil target called “Arad” has a
salty chemistry dominated by iron-bearing sulfates. The composition is
similar to that of a more silica-rich target, “Paso Robles,”
earlier in the rover’s journey through the “Columbia Hills.” The
presence of salt can be considered another clue to the existence of
water on Mars.

Spirit had a bit of difficulty driving out of the sandy area near Arad.
Rover instruments recorded slip rates as high as 92 percent on the
wheels before Spirit’s drivers designed a command strategy that took
Spirit away from the sand dunes and closer to Home Plate.

Spirit’s engineering team broke a record the previous week, on sol 720
(Jan. 12, 2006), by taking only 2 hours and 35 minutes to plan and
validate the uplink commands for the rover. To put that in perspective,
at the beginning of the mission, when all of the rover’s systems and
science team members were brand new, the process took more than 13

Sol-by-sol summaries:

Sols 723 to 725 (Jan. 14 to 17, 2006): Spirit began a campaign to study
different targets of the feature named Arad, using instruments on the
robotic arm, including the microscopic imager, Moessbauer spectrometer,
and alpha particle X-ray spectrometer.

Sol 726: Spirit terminated the sol’s drive early because of high
slippage on sandy surfaces. The rover took images and conducted
atmospheric observations using the miniature thermal emission

Sol 727: Spirit drove 26 meters (85 feet), took images with the
navigation and panoramic cameras after the drive, and conducted
atmospheric studies using the miniature thermal emission spectrometer.

Sol 728: Rover planners successfully designed a drive that took Spirit
away from the sand dunes and closer to Home Plate. Spirit took images
following the drive.

Sol 729 (Jan. 21, 2006): Spirit conducted untargeted atmospheric remote


As of sol 728 (Jan. 20, 2006), Spirit’s total odometry was 6178.96
meters (3.94 miles).