The NASA Pi Day Challenge Slideshow | NASA/JPL Edu

The NASA Pi Day Challenge Slideshow | NASA/JPL Edu

Mars Marathon

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The Mars Exploration Rover Opportunity has been driving on the Red Planet for more than 11 years -- not bad for a mission only planned to last for three months! Opportunity has already beat the off-Earth driving distance record of 39 kilometers and is approaching a marathon distance: 42.195 kilometers.

When Opportunity reaches the marathon mark, how many times will its 25-centimeter diameter wheels have rotated?

Learn more about the Mars Exploration Rover Opportunity