They have taken us on one of the great journeys of exploration. An expedition to Mars, to places that have never been seen by human eyes. Mars rovers Spirit and Opportunity were expected to last three months. Now, more than seven years later, Opportunity is still rolling. Burt Spirit has reached the end of the road. On Tuesday, July 19, at 3:15 p.m. PT, the Mars Exploration Rovers team celebrated the great success of Spirit's mission.