Mars Exploration Rover Update - March 16, 2006

SPIRIT UPDATE: Spirit Continues Driving on Five Wheels - sol 778-783,
Mar 16, 2006:

Spirit continued to make progress toward “McCool Hill” despite a
reduction in solar energy and problems with the right front wheel. The
team plans to have the rover spend the winter on the hill’s
north-facing slopes, where the tilt toward the sun would help maximize daily output by the solar panels. On Spirit’s 779th sol, or Martian day (March 13, 2006), the drive actuator on the right front wheel stalled during a turn to adjust the position of the rover’s antennas. The stall ended the
day’s drive, which brought Spirit 29 meters (95 feet) closer to McCool,
still approximately 120 meters (390 feet) away.

Engineers conducted tests on sols 781 and 782 (March 15 and 16, 2006)
on a testbed at the Jet Propulsion Laboratory as well as remotely on
Spirit. Further analysis is needed to determine what caused the right
front actuator to stop working. Meanwhile, the operations team has
successfully commanded Spirit to drive using only 5 wheels. Engineers
plan to have Spirit continue driving backward with five healthy wheels
while dragging the right front wheel.

Sol-by-sol summaries:

Sol 778 (March 12, 2006): Spirit spent the day conducting remote
atmospheric sensing.

Sol 779: Spirit drove about 29 meters (95 feet) and acquired post-drive
images. A fault in the right front wheel drive actuator terminated the

Sol 780: Spirit spent the day recharging batteries and re-transmitting
information about the previous day’s drive to Earth. Spirit collected
additional imagery of the right front wheel.

Sol 781: Spirit completed diagnostic tests and drove 3.9 meters (13
feet) using only five wheels. Diagnostic tests showed that the
right-front-wheel problem involved the drive actuator, not the

Sol 782: Rover drivers planned a drive of approximately 12 meters (40
feet) using only five wheels.

Sol 783 (March 17, 2006): The operations team planned to have Spirit
spend the day sleeping to charge up the batteries.

As of sol 781 (March 15, 2006), Spirit’s total odometry was 6,797
meters (4.22 miles).