One of the U.S. Mars rovers is preparing to dig into soil to look for evidence that water once flowed on the planet that could have supported life.
The Opportunity rover has ended its third week on Mars by taking its longest drive so far, about nine meters. The six-wheeled vehicle finished the trek with a U-turn to prepare for its first trenching operation later Monday.
The rover is at the slope of the crater in which it landed. The spacecraft's sensors have detected that the ground there is rich in a mineral called hematite, which usually forms in water.
Mission controllers are aiming its instruments to analyze the surface, after which they will command Opportunity to spin one wheel to dig below it.
On the other side of Mars, the Spirit rover examined an unusual rock called "Mimi." Scientists will look at its structure and composition to determine the environment in which it formed.
Later Monday, Spirit will take a relatively long drive of 25 meters, nearly one-tenth the distance to a crater nicknamed Bonneville that the mission team wants to inspect.