http://news.com.com/2100-7337_3-5630113-2.html
Some of Spirit's aches of age have also gone away. In June, the motor driving its right front wheel started drawing two to three times as much electrical current and appeared in danger of burning out. Mission controllers limited the use of the wheel, driving on the other five. Then, three months ago, the motor returned to its normal functioning.

Dust gathering on Spirit's solar panels had cut the amount of energy they generated each day from 900 watt hours initially to just over 400.
Then on March 9, the power output suddenly jumped up to 800 watt-hours, nearly as good as new. Spirit's cameras detected several dust devils--mini tornadoes--in the area, and apparently one passed directly over the rover, blowing away the dust.

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