Mars rover twin ready to roll onto planet's surface

NASA's Opportunity rover stretched out its rear wheels in preparation for rolling across the surface of Mars, possibly a day earlier than expected, and the space agency said its twin, Spirit, "will be perfect again" after repairs of crippling software problems.

Except for its robotic arm, Opportunity finished unfolding and standing up from its landing position and is ready to travel the final 10 feet from its lander to the surface of Mars, possibly late on Saturday, said project manager Pete Theisinger.

NASA earlier had said Opportunity could be ready to reach the surface by Sunday.