Pasadena, Calif. ? NASA’s Spirit rover cut the last umbilical cord to its lander and rolled for the first time since reaching Mars, positioning itself for the start of its journey across the surface, officials said Tuesday.

“Spirit is a rover,” flight director Chris Lewicki said of the six-wheeled vehicle, which previously stood up from a crouch but otherwise had been largely immobile since landing Jan. 3.

Nevertheless, the rover’s wheels have yet to touch the surface of Mars. The rover merely severed the last cable attaching it to its lander and backed up 10 inches atop the platform, starting a three-part turn to line itself up with the exit ramp it will use to reach the rust-colored ground.

Spirit is expected to roll the 10 feet onto Martian soil late today or early Thursday.

Spirit is expected to follow a meandering path, pausing to sample rocks and soil in its search for evidence that the planet was once wetter and more hospitable to life.

The rover may try to climb the 18-foot-high lip of a crater, about 825 feet away, and survey the dunes believed to be inside. Then it may try to reach distant hills — or die trying.

The tawny hills in the distance are about 330 feet high. Scientists believe the depression in which Spirit landed once contained a lake. If so, the hills could preserve evidence of any waves that may have lapped against their slopes.

But the hills are nearly two miles away, or about five times farther than Spirit is expected to be able to travel. Spirit probably will conk out before reaching the hills.