Free Spirit: Third extrication drive ends with wheel stall

Spirit experienced a wheel stall with the right-rear wheel during the second step of a two-step drive on Sol 2092 (Saturday, Nov. 21). This is not the same wheel that stalled on Sol 1899 (May 6), the left-middle wheel.

On Sol 2092, the right-rear wheel did not experience a hard stall like what was seen on Sol 1899. Instead, it stalled because the wheel's progress fell behind the expected rotation rate.

The rover had completed about 4 meters (13 feet) of commanded wheel spin before the stall terminated the drive.

This blink comparison aids evaluation of a drive by NASA's Mars Exploration Rover Spirit during the rover's 2,092nd Martian day, or sol (Nov. 21, 2009). This was the third drive commanded by the rover team in an effort to extricate Spirit from loose sand where the rover became embedded in April 2009. Credit: NASA/JPL-Caltech

The center of the rover moved about 4 millimeters (0.2 inch) forward, 3 millimeters (0.1 inch) to the left and about 3 millimeters (0.1 inch) down.

The rover suspension stayed within the tighter limits set for the drive, and there was only a fractional change in rover tilt.

The plan ahead for today, Nov. 23, is to sequence a set of diagnostics to explore the right rear wheel stall. The diagnostics will include a rotor resistance test, a possible steering test, a small backward rotation of just the right-rear wheel and a short (about 1 meter, or 3 feet) forward commanded motion of the rover. Resumption of the extrication driving would be no sooner than Wednesday.

 

Source: Jet Propulsion Laboratory
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