Life on Mars

With each passing day, those peppy robots on Mars - Spirit and Opportunity - churn out extraordinary new views of the red planet. Each robot is over a year in operation, relaying a steady stream of eye-catching photos.

And more than once, the Mars machinery has sent back an image that stirred up a promising eureka moment: Finding evidence for life on that remote world.

A case in point, during a recent run of Spirit in the Columbia Hills, the robot used its arm-mounted devices to poke and probe a select Mars rock. One piece of hardware -- the Rock Abrasion Tool, known better as the RAT -- is on hand to expose fresh martian rock.

The RAT utilizes a single diamond matrix wheel to scrape the rock surface. It does this ever so slightly and progressively to achieve a wanted depth. The abraded surface is actively swept clean by a brush to prepare it for scientific examinations.

Once the rock was worked over, Spirit's Microscopic Imager went in for close-up looks at the results.

And within the images, an odd feature could be seen, seemingly a pattern of something more biological than just rock.

First impression

"The first impression I got -- based on the morphology alone -- was how similar it looked to a common terrestrial foliose lichen," said Barry DiGregorio, a research associate for the Cardiff Centre for Astrobiology in the United Kingdom. "On Mars, however, as we all have learned from past experience, looks can be deceiving," he told SPACE.com.

DiGregorio said he was struck by the fact that the entire rock outcrop on which this feature is found looks in places like it has a moss-like texture to it. "In the absence of any spectroscopic data, it's difficult to say for certain what it is. The radial pattern may turn out to be similar to spherical dendritic iron oxides," he added.

Indeed, looks can be deceiving, concurs Stephen Gorevan, payload lead for the RAT on the Mars Exploration Rover project. He's also chairman of Honeybee Robotics in New York, the cutting-edge group that designed, developed, and operates the RAT.

Honeybee Robotics creates robots, flight subsystems, automated drills and other machines destined for work on Earth, Mars, and beyond.

Bet the farm

Gorevan told SPACE.com that the Spirit snapshots in question show a portion of a RAT brush mosaic, along with the actions of the rover's M?ssbauer Spectrometer. That device carries out a detailed analysis of a rock once put flush into position on the object of interest.

"While I have not traced the precise path and geometry, it is suspected that the central 'fuzzy' patch is due to the M?ssbauer placement onto a portion of the mosaic where brush bits had accumulated," Gorevan noted.

The M?ssbauer contact plate picked up the brushed bits by a sticking action that Gorevan and others on the rover team have seen before. A related event happened earlier in the robot's mission, he explained.

"The M?ssbauer left a screw mark in some dust and it was assumed that there was a ratting and some very weird structure had been uncovered. Like I said, I can't prove my hypothesis yet, but I would bet the farm that it was something close to what I am indicating," Gorevan said.

Instrument contact

Also asked about the curious feature, Mars Exploration Rover science leader, Steve Squyres from Cornell University reported: "Nothing very exciting...RAT brush mark."

Gorevan