March 18, 2005

Rover Soldiers On

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15 months into its extraterrestrial mission, Cornell’s Spirit keeps on roving.

Spirit, one of two twin golf cart-sized Mars rovers, made what Prof. Steve Squyres ’81, astronomy, the principal investigator of the Mars Exploration Rover Project, called “a pure serendipitous discovery.” While climbing a steep slope, the rover turned up soil that seemed unusually bright.

“So we thought, ok, just in case this is something interesting we’ll reach out the arm and take a quick taste of this thing before we move on,” Squyres told the Sun. The soil showed the highest concentration of sulfur ever found on Mars. Such high salt concentrations suggest that certain areas of Mars may have been habitable at some point in the past.

“There’s so much salt. There’s no conceivable way that there could be so much without water being involved. What that says is that these were once habitable environments; whether or not life was actually there we do not know,” Squyres said.

In another unexpected event, Spirit encountered a Martian windstorm last weekend that likely swept large amounts of accumulated dust from the rover’s solar energy panels. Initially expected to last three months, the rovers’ 15 months of operation has exceeded the expectations of even the most optimistic NASA engineers. The natural cleaning provided by the windstorm could extend Spirit’s lifetime even longer.

“When we first landed, the solar rays were putting out 900 watt-hours,” Squyres said. As dust from the Martian atmosphere accumulated on the panels, preventing the absorption of the sun’s rays, power output declined to roughly 350 watt-hours. Since they require at least 280 watt-hours of power to operate, engineers were beginning to worry about the rovers’ future. In the wake of last weekend’s events, however, Spirit is now producing close to 800 watt-hours of solar energy.

According to a NASA press release, “team members speculated that Spirit’s power boost, like similar ones on Opportunity in October, resulted from wind removing some accumulated dust from solar panels. Spirit captured pictures of dust-lofting whirlwinds on March 10, adding evidence for windy local conditions.”

Along with the increase in energy output, however, the dust storm wrought some negative consequences on the image quality of the rover’s cameras.

“The dust storm is good for increasing the available solar input but at the same time, it’s making it harder to get true-color images of the surface,” said Alex Shapero ’06, a student who works on the calibration of the panoramic images. The storm appears to have deposited dust on the rover’s calibration target, a device that filters out atmospheric contamination in the images and allows technicians to develop the pictures in their true colors.

In the coming weeks, the Mars team hopes to reach the summit of Husband Hill, one of the highest points inside Gusev crater. Scientists hope that the rover will encounter different types of rocks on its trek to the top of Husband Hill, and on its exploration of the other side. “It turns out there would also be a hell of a view from the summit if we get there,” Squyres said.

Such discoveries could prove extremely helpful in future explorations of the red planet. “In addition to learning about the geography, we’re learning about the weather of the planet and about Martian geology,” said Diane Bollen, Athena Project coordinator. “We went in there not knowing a whole lot about the atmospheric science of the planet. The more we learn, the more future missions can adapt.”

Cornell’s Herbert F. Johnson Museum of Art will display selected images from the mission in an exhibit entitled “Rover Landings: Cornell on Mars.” According to Cornell’s website, “team members have selected their favorite images and panoramas, from both a scientific and artistic viewpoint, from among the more than 50,000 images acquired by both rovers.” The exhibit will open March 26 and run through April 24.

Archived article by Josh Goldman
Sun Contributor