Tire Tracks, Empty Planet

More from Mars. Martian Rover Opportunity's tire tracks traverse a vast Martian plain of dunes:



Last week Opportunity surpassed Viking 1 as the longest running mission on Mars, now extending well over six years. Landing in 2004 in Meridiani Planum, the robotic Opportunity has embarked on its longest and most dangerous trek yet, now aiming to reach large Endeavor Crater sometime next year.

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