NASA (search) said Tuesday it has picked two locations on Mars for its Spirit rover (search) to visit: a nearby crater and, later, a distant cluster of hills the explorer will reach — 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 during a news conference at NASA's Jet Propulsion Laboratory (search).

Spirit remained on track to roll onto the martian soil late Wednesday or early Thursday. The rover cut the last cable attaching it to its lander and began a three-part turn to line it up with the exit ramp it should use to reach the ground, flight director Chris Lewicki said. The rover also rolled for the first time, moving backward on the lander about 10 inches, he said.

"Spirit is a rover," Lewicki said of the robot, which had been largely immobile on the landing vehicle since landing Jan. 3.

Pinpointing the rover's location, members of the mission determined Spirit landed about 990 feet to the southeast of where it first bounced down, swaddled in air bags, on Mars, said Tim Parker, the landing site mapping scientist.

Revised data suggest it bounced 28 times before coming to a rest about 825 feet to the southwest of a low-slung crater, said Rob Manning, manager of the entry, descent and landing portion of the mission.

Once off the ramp, Spirit will park for a day or two to give scientists a chance to study the chemistry and mineralogy of the area before it roams any farther. One of the first things Spirit will do is extend its robotic arm to touch and capture soil samples. It also will make measurements of any rock that happen to be in range.

The first target after that is the crater, a destination it will take days if not weeks to reach. NASA plans to then send the rover to the southeast of the crater, toward a cluster of hills nearly two miles away. The distance is about five times Spirit's maximum driving range, meaning the rover could die on the way unless it far outlives its expected 90-day lifetime.

"We are going to head for those hills," Squyres said, adding later, "We are going to get as close to them as we can."

NASA on Monday released the first 360-degree, color panorama of the terrain around Spirit.

A team scientists and engineers assembled the sweeping panorama from 225 separate images.

"The whole panorama is there before us. It's a great opening for the next stage in our mission, which is getting off the lander and out into this field," said Michael Malin of Malin Space Science Systems, a member of the mission science team.

Spirit still needs to turn 70 more degrees to its right, in two steps, before it can roll off its now inert lander.

"The analogy being we're about to kick the baby bird from the nest," said Kevin Burke, lead mechanical engineer for the roll-off process.

The new panorama shows a landscape that is pancake flat in some directions and rolling in others. The topography appears dominated by mounds of material cast off when asteroids or comets pummeled the martian surface in the distant past, punching out craters.

Spirit is working in chilly temperatures that, at their highest, would be familiar to anyone shivering through the cold snap that hit the United States in recent weeks.

The daytime high is a relatively balmy 15 degrees Fahrenheit, project scientist Joy Crisp said.

"I checked, this corresponds to Minneapolis' low tonight," Crisp told reporters Monday.

The martian nighttime low is minus 100 Fahrenheit, or about the coldest it gets at the South Pole, Crisp added.

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