spacetoday.net: Spirit loses use of one wheel

Posted: Tue, Mar 21, 2006, 8:30 AM ET (1330 GMT)
Mars Exploration Rover (NASA/JPL)

One of the six wheels on the Mars Exploration Rover Spirit has stopped working entirely, forcing rover engineers to drag the wheel along as they try to move the vehicle into a safe position for the coming winter. The right-front wheel on Spirit had been experiencing problems since mid-2004, when its motor starting drawing large amounts of current. Driving the rover backwards redistributed lubricant and allowed the wheel to work normally again, but last week the motor for that wheel stopped working entirely. Rover drivers play to drag the wheel along as they move the rover to a north-facing slope, where the spacecraft can get enough sunlight to operate throughout the coming Martian winter. As of late last week Spirit was about 120 meters away from its desired location and moving at about 12 meters per day. Last week NASA named John Callas as the new manager of the rover program, which includes operations of both the Spirit and Opportunity rovers.