Scientists prepare NASA rover to roll onto Mars soil this week

PASADENA, California (AP) — Since NASA’s little robot explorer Spirit landed on Mars, it has snapped breathtaking pictures and captured imaginations. This week, scientists hope it will finally take its first trip on Martian soil.

National Aeronautics and Space Administration scientists said they hope to have Spirit roll down a ramp onto the dusty, rock-littered terrain of Gusev Crater late Wednesday night or before dawn Thursday.

Scientists had originally intended for Spirit to wheel away earlier, but the ramp it would have taken to the surface of Mars was blocked by deflated air bags, so it must be turned and directed down a secondary ramp. They said the rollout could be delayed another day if necessary.

The golfcart-sized, unmanned rover was unfolded Friday from a tight crouch and raised to its full height of 4 feet, 11 inches (1.5 meters). Cables holding the middle set of its six wheels were cut Saturday, leaving just the umbilical attached. And in another milestone, the robotic arm was swung up to lock in front of the rover for driving position.

The rover’s status was “pretty darn perfect,” with plenty of power to perform its chores, excellent communication and a nice, flat position for its exit, said Arthur Amador, a mission manager, said at a news conference.

Scientists on Sunday used a rover mock-up to plan a dress rehearsal of the slow dance that will put the craft into position to leave the lander. Over two days, the craft will make about a 120-degree turn to the right in three stages, periodically beaming back photos so engineers can check its position.

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.

John Callas, science manager for NASA’s Jet Propulsion Laboratory, said things were going so well that extra time on the lander allowed a bonus of “unplanned science.” Researchers planned to take stereo, full-color panorama photographs of the area where the rover will touch down. That will become part of a 360-degree view still being assembled.

Also, a spectrometer that sees infrared radiation — heat — will take a look at three places, including an intriguing feature dubbed Sleepy Hollow that lies about 40 feet (12 meters) away.

Scientists believe the 30-foot (9-meter)-diameter depression is a dust-filled impact crater, one of dozens that pock an otherwise flat landscape. The spectrometer can help determine the makeup of rocks and soil.

Callas said the mission has moved into what is being called a tactical phase, with scientists making decisions on the fly based on the newest data from the rover.

From now on, the team will quickly analyze photographs and will plan Spirit’s day during the 17-hour period when the craft sleeps. Swiftness is important given that the rover’s rolling mission will cost about $4 million a day, Callas said.

The rover should spend 90 days traveling several hundred yards (meters) to analyze rocks and soil for indirect evidence of life. The duration of the mission depends on the amount of power available to the rover, which is solar-powered.

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

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