NASA Rovers Reach Mars Milestone
Mars rover Opportunity is imaging its sandy surroundings. Ground controllers want to understand why the robot got stuck in sand dune.
Credit: NASA/JPL.

A milestone has been reached for those hard-at-work red planet rovers, Spirit and Opportunity. Late last week, ground controllers hit 1,000 sols of working with the robots on the surface of Mars. A sol is duration of a solar day on that faraway planet.

On June 9, Opportunity hit 490 sols and Spirit attained 510 sols since their independent landings in January 2004.

Reaching 1,000 sols "is a remarkable accomplishment," said Steve Squyres, lead scientist for the Mars Exploration Rover (MER) project at Cornell University in Ithaca, New York. He tipped his hat to friends, colleagues and comrades, engineer and scientist alike, on the MER uplink team.

In his Cornell-based web site on the Mars rovers, Squyres noted that the Earth-to-Mars uplink process - controlling the robots across interplanetary space - "is intense, engrossing and exhausting."

Escape from "Purgatory Dune"

"Good things are happening on both sides of the planet," Squyres said, in terms of robot operations.

At Meridiani Planum, the Opportunity Mars rover is now free of a sand dune that halted its movement for five weeks. "At Meridiani, we'll soon begin our first maneuvers to reorient the rover so that we can study the feature that got us...and then be on our way again," Squyres said.

The menacing feature that trapped Opportunity now has a name: "Purgatory Dune".

"We weren't calling it anything back when we were stuck in it, but now that we're out, it seemed there ought to be a name for the thing," Squyres explained.

Are there any best guesses of why that particular dune snagged the rover, and are other sand traps lurking in the area? "No guesses," Squyres told "We're going to collect data and then think hard about it...not try to guess."

What information would imagery of Purgatory Dune provide rover ground controllers and scientists? There's need to look at grain size, detailed topography, whether or not the dune has a crust - and if it does have a crust, what that crust is made of, Squyres said. "Basically, everything we can safely learn about it that might be of some help in the future."

Spirited spiral: up and to the right

On the other side of Mars from where Opportunity rests, the Spirit rover is doing survey work within the Columbia Hills at Gusev Crater.

Spirit is scoping out which way rocks there are tilted. There are very interesting outcrops in an area dubbed "Tennessee Valley", and some "really good-looking stuff" on the far wall of the valley, Squyres said.

The Spirit rover team has decided to head up on a section tagged as "Husband Hill".

"We're not going to try a frontal assault this time. Instead, we're going to spiral up and to the right, working both upslope and also cross-slope simultaneously. Whether we'll actually reach the summit is an open question at this point. But we're convinced that the route we've chosen offers the quickest path to a view of whatever's on the south side of the hill... and that's what we want to see next," Squyres concluded.

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