PASADENA, Calif. (AP) – 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 Wednesday 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 and survey the dunes believed to be inside. Then it may try to reach distant hills – or die trying.

“We know where we are now and we also know where we’re going,” Steven Squyres, the mission’s main scientist, said at NASA’s Jet Propulsion Laboratory.

The unnamed crater is about 825 feet away. The asteroid or meteor that punched out the crater could have exposed ancient rocks that may contain important evidence, Squyres said.

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.

Martian temperatures of minus 100 degrees Fahrenheit and colder wreak havoc with spacecraft components, stressing and, ultimately, breaking them. The last rover NASA sent to Mars, 1997’s Sojourner, lasted nearly 90 days before it succumbed to the cold.

Even if Spirit fails to reach the hills, its camera’s 20/20 vision should be able to pick out from afar the horizontal markings that could suggest an ancient shoreline, said Tim Parker, the landing-site mapping scientist.

The $820 million project includes a second, identical rover named Opportunity that is expected to land on the opposite side of the Red Planet on Jan. 24.