For nearly six years, Spirit roamed Mars, experiencing a number of close calls. In fact, the solar-powered robot has driven backwards since its right front wheel jammed in 2006.
Spirit’s most challenging ordeal yet began in April, when it got bogged down in a patch of loose soil on the edge of a small crater. As scientists plotted Spirit’s escape for months, they dubbed the area Troy, after the city the ancient Greeks struggled against in myth for a decade.
As frustrating as Spirit’s dilemma has proven, it has yielded an unexpected insight.
“Spirit had to get stuck to make its next discovery,” said geologist Ray Arvidson of the Washington University in St. Louis. “The rover’s spinning wheels have broken through a crust, and we’ve found something supremely interesting in the disturbed soil.”