NASA took the rover Opportunity on its first real drive on Mars, a trip across pebbly soil that appears to be unlike anything else seen on the surface of the Red Planet, scientists said Thursday. Opportunity rolled forward about 3m overnight, leaving it halfway to an outcrop of rocks that scientists want to spend days studying, said Guy Webster, a spokesman for the Jet Propulsion Laboratory. It was the first time the rover had moved since leaving its lander Saturday.