Opportunity knocks for Mars rover

The Mars rover Opportunity has freed itself after nearly five weeks of being stuck in a sandy dune.

Engineers at the Jet Propulsion Laboratory, which manages the mission, cheered when images beamed back to Earth showed the wheels of the robotic explorer were free, project manager Jim Erickson said.

A photograph taken by Opportunity showed the long tracks of its wheels crossing a featureless dune on the Meridiani plains.

The six-wheeled robot slid in the fine dust and sand on April 26.