Diagnostic tests run on the wheel's motor are consistent with the results on the ground, which indicate an open circuit.

Controllers ordered Spirit to drive across the Martian surface on sols 792 and 794 (March 26 and 27), but the team is developing new strategies for five-wheel driving in the test facility at Jet Propulsion Laboratory. So far, those new strategies seem to be working, but the team reports that soft soil and slopes have been making uphill progress difficult.

At the end of last week, the JPL team decided to stop trying to advance along a route Spirit had been attempting in recent sols and, instead, to drive back downhill a few meters and then begin a different route toward a north-facing slope.

Meanwhile, NASA mission controllers restored the Mars Odyssey orbiter's communication-relay capacity on March 25, and the spacecraft resumed its support of both Spirit and its twin rover Opportunity.

Spirit sol-by-sol highlights: Sol 790 (March 24): Spirit completed its usual morning science observations of assessing the clarity of the sky (a variable called "tau") with the panoramic camera, and checking the sky and ground with the miniature thermal emission spectrometer. Before shutting down for this light-activity sol, the rover used 13 different filters of the panoramic camera to examine soil that had been churned up in wheel tracks.

Sol 791: Spirit used the panoramic camera for assessing sky clarity and for surveying some rocks. It used the miniature thermal emission spectrometer for sky and ground observations and to examine the disturbed soil in the wheel tracks.

Sols 792 and 793: Spirit turned about 125 degrees to face a new drive target and began to drive toward it. The drive ended a few meters later when the rover detected 71-percent slippage, so on sol 793, Spirit completed a light schedule of remote-sensing observations.

Sols 794 and 795: Spirit drove 5.7 meters (19 feet) on sol 794, but most of the odometry change was a part of the heading change, rather than progress toward a destination. Again, high slip terminated the drive. As in the previous two-sol plans, there was light remote sensing on the second sol.

Sols 796 and 797: Spirit's sol 796 uplink time was during a Mars Reconnaissance Orbiter aerobraking maneuver and the two spacecraft cannot use the same radio band at the same time, so the rover team used forward commanding relayed via Odyssey to uplink Spirit's sequences of commands for sols 796 and 797.

The plan for sol 796 was to turn 60 degrees clockwise toward a new waypoint and drive toward it using visual odometry to help check for slip. The rover drove 4 meters (13 feet) before the drive stopped due to excessive (61 percent) slippage. As on the previous drive attempt, most of the added odometry was in the turning, not forward progress. After the drive, Spirit acquired images to help the uplink team analyze possible alternative routes to north-tilted slopes.

As of sol 796 (March 30), Spirit's odometry totaled 6,836.48 meters, or 4.25 miles.

Related Links
Mars Rovers at JPL
Mars Rovers at Cornell

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