Mars rover examines 'flaky' rock

Nasa has two rovers on the planet

The US space agency's robotic Mars explorer Spirit has been investigating an unusual "flaky" rock which project scientists have dubbed "Mimi".

Nasa team members think the rock's apparent flakiness indicates layering, which suggests it formed over time.

Sedimentary rocks are just such an example of layered rocks and are the product of material deposited by the action of either water or wind.

Spirit is to spend 90 days on Mars looking for signs of past liquid water.

The rover used the science instruments on its robotic arm to examine the rock during its 42nd Sol, or Martian day, which ended on Sunday.

On Sol 43 (Monday), mission scientists plan to send the rover on a "mega drive", which will consist of a morning drive of about 25 metres (82 feet).

It will then take pictures of the scene ahead.

The rover will then take a brief rest. The images taken after its morning drive will be used to guide an optional afternoon drive.

Spirit is currently about 270 metres (885 feet) from the impact crater nicknamed "Bonneville", where it is headed.

On Saturday, Opportunity completed its longest drive on the surface of Mars so far - about 9 metres (30 feet) - during its 21st sol on Mars.

The rover finished the drive with a U-turn, at a place selected for its first "trenching" operation.

This involves the rover spinning one wheel to dig below the soil on a slope rich in the iron-rich mineral grey haematite.

Opportunity landed in a shallow impact crater in a region known as Meridiani Planum.