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| One of the wheels on Nasa's Martian rover Spirit has stopped working. The robotic vehicle is now dragging the wheel as it moves to a slope where it can get maximum sunshine on its solar cells to sustain it through the winter. Spirit's right-front wheel has played up before because of a lubrication problem, but engineers on Earth were able to return it to normal operation. This time, however, it appears to be the motor that rotates the wheel that has ceased to function. Last Updated: Saturday, 18 March 2006, 19:59 GMT E-mail this to a friend Printable version Front wheel on Mars rover stops The rovers have gone on working far longer than anyone expected One of the wheels on Nasa's Martian rover Spirit has stopped working. The robotic vehicle is now dragging the wheel as it moves to a slope where it can get maximum sunshine on its solar cells to sustain it through the winter. Spirit's right-front wheel has played up before because of a lubrication problem, but engineers on Earth were able to return it to normal operation. This time, however, it appears to be the motor that rotates the wheel that has ceased to function. "It is not drawing any current at all," said Jacob Matijevic, rover engineering team chief at the US space agency's Jet Propulsion Laboratory in Pasadena, California. One possibility engineers are considering is that the motor's brushes - that deliver power to the rotating part of the motor - have lost contact. Engineers can simulate solutions on an engineering model back on Earth The motors that rotate Spirit's wheels have revolved more than 13 million times, far more than called for in the rovers' design. The vehicle entered its third year on the planet on 3 January... |
