UPDATE: Story first posted 7:00 a.m., EST, January 19, 2003

PASADENA, Calif. -- Easy pickings is what NASAs Spirit rover has found on Mars.

Over the weekend, the robot was steered to a select rock at the Gusev Crater landing site, inching up to the target for detailed camera inspection.

Scientists identified three rocks as possible driving targets. Two were dubbed "Sushi" and "Sashimi" and sat in an area that was tagged the Wasabi region. The third was the pyramid-shaped rock, Adirondack.

"We went for a Sunday drive," said Mark Adler, JPL Mission Manager for the Mars Exploration Rover project. Spirit spurted across the terrain in a series of short jaunts, as well as arcing and turn-in-place maneuvers.

The total drive to Adirondack took some 30 minutes, with picture-taking sessions done during the trek. A little over 10 feet (2.85 meters) was covered by Spirit from a standing start near the lander.

Driving the rover to Adirondack has provided valuable data for future outings, said Eddie Tunstel, Mobility Engineer for the Mars rovers at JPL.

Once Spirit eased on up to the rock, it "wiggled" its wheels in the martian surface. "Basically to get good footing," Tunstel said. Now resting within a foot of Adirondack, that distance is "well enough in reach of the robotic arm," he said.

Gaining solid footing on Mars means that Spirit should be adequately anchored in dirt, good enough to apply the robots Rock Abrasion Tool (RAT) -- one of four geological instruments mounted on the rovers outstretched robot arm.

Scientists on the rover team are assessing if the chunk of Mars is an ideal candidate for the RAT -- a fast-spinning rock grinding device.

Spirits new jaunt across the martian landscape placed it in face-to-face position with Adirondack. Over the next few days, the rover is to stay put and gather information about the rock.

Dave Des Marais, a researcher from NASAs Ames Research Center, said careful appraisal of the rock is planned, including study of its cracked face. Those observations are anticipated to turn Adirondack into a "time capsule" - a way to discern clues about the objects geological history.

Late last week, Spirit made use of a microscopic imager, built to help scientists analyze and understand martian rocks and soils by taking very high resolution, close-up images.

Spirit has rotated a turret of tools affixed to its robot arm, utilizing two spectrometer instruments over the weekend on the same patch of soil examined by the microscope.

A Mssbauer Spectrometer singles out types of iron-bearing minerals. The Alpha Particle X-ray Spectrometer identifies the elements in rocks and soils.

First results from these spectrometers, both supplying good data, will be explained at an early morning press briefing here at JPL on Tuesday.

At Spirits present location, the Mssbauer Spectrometer, Alpha Particle X-ray Spectrometer, and the Microscopic Imager are to take turns focusing in on Adirondack, both before and after the rock has undergone a RAT session, Des Marais told SPACE.com .

This before-and-after analysis of the rock, Des Marais explained, should give a handle on processes that have influenced Adirondacks current geological state.

Adler said that Opportunity -- the twin to Spirit now zipping toward Mars -- is on target for its entry, descent, and landing on Mars, making a red planet touchdown on January 24 at about 9:05 p.m. Pacific Standard Time.

Opportunitys trajectory was adjusted late last Friday, putting it on a precise heading for Meridiani Planum, on the opposite site of Mars from where Spirit landed.

"Right now, it doesnt look like any more trajectory maneuvers are slated for Opportunity," Adler noted.

Adler said that when the orbiting Mars Global Surveyor flies over the Meridiani Planum area, it takes temperature profiles of the atmosphere that Opportunity will cut through, as it dives to its landing spot.

Dust storms elsewhere on Mars have altered the atmosphere in the Meridiani Planum region.

"Weve been getting daily reportsso weve got a pretty good idea of how the atmosphere has changed over time," Adler said. "Its starting to cool off now, meaning the air in which the spacecraft is going to deploy its parachute will be denser.

Engineers here at JPL have been busy reviewing Spirits entry, descent, and landing on January 3 to ascertain the timing sequence for safely dropping Opportunity onto Mars.

"Overall, Im not worried about it. Weve got a ton of margin," Adler told SPACE.com . Because of the dust storm activity, engineers have decided to deploy Opportunitys parachute a little bit higher than originally planned, and a few seconds earlier, he said.

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