Monday, March 4, 2013

[Geology2] Roving around Erebus



Person looks at laptop with small vehicle in background.
Photo Credit: Peter Rejcek
Engineer Rebecca Williams controls Yeti, a four-wheeled robot that carries a ground-penetrating radar, on the slopes of Erebus volcano. Yeti is scanning over an ice cave created by the heat and gases vented by the volcano through fissures.

Roving around Erebus

Robot scans ice caves on Antarctica's famous volcano

By Peter Rejcek, Antarctic Sun Editor
Posted March 1, 2013

Twenty years after an arachnid-shaped robot stalled out on its descent into the noxious crater of an Antarctic volcano, an altogether different rover could be found on the slightly safer slopes of Mount Erebus.

The four-wheeled Yeti External Non-U.S. government site rover, towing a rubber tire over the snow-covered flanks of the volcano, is also on a different mission — scanning for ice caves — than its predecessor robot, an eight-legged, mechanized metal explorer dubbed Dante.

The spider-like Dante had been designed under a NASA External U.S. government site program, with the intent of one day walking on the moon or Mars. Antarctica is a relatively convenient analog for the otherworldly weirdness that might exist in the cosmos.

Eight-legged machine descends slope.
Photo Credit: USAP archives
The eight-legged Dante robot begins its descent into Erebus volcano during the 1992-93 summer field season.

The National Science Foundation (NSF) External U.S. government site, which manages the U.S. Antarctic Program (USAP) External U.S. government site, facilitated a trip to the Ice for Dante during the 1992-93 austral summer field season. The plan called for the robot to walk and rappel its way into the crater of Erebus, which boasts a rare magma lake inside. Unfortunately, Dante only picked its way down the steep incline about eight meters before a fiber optics communications cable broke and ended the experiment.

Pint-size compared to the Tolkien-esque giant spider that visited Erebus two decades ago, Yeti bears no resemblance to its namesake of legend. Tipping the scales at only about 80 kilograms, the all-terrain robot is autonomous, so no cabled tether to foul or break. It has already proven its toughness in the cold, with previous deployments to both Antarctica and Greenland.

Smoke rises from volcano.
Photo Credit: Peter Rejcek
Smoke rises from Erebus volcano.

Still, this is the first time that Yeti and its handler, Rebecca Williams, an engineering graduate student at Dartmouth College External Non-U.S. government site, have been to a volcano. Williams and the rest of the team at Dartmouth's Thayer School of Engineering External Non-U.S. government site, led by professor Laura Ray External Non-U.S. government site, had designed and built Yeti for an altogether different purpose.

"We didn't consider anything like this. He was developed solely for crevasse detection," Williams explains in slightly labored breaths as she sets up her laptop in the clear but cold afternoon at about 3,400 meters. "We didn't think there was another application."

Yeti and its ground-penetrating radar (GPR), located in the rubber donut hole that it pulls, is normally employed to find empty spaces hiding just below the snow surface. In Greenland, it has served as a sort of scout for a tractor train that moves cargo and fuel across the ice sheet in support of Arctic research.

In Antarctica, Yeti has traveled as far as the geographic South Pole, where it surveyed the site of an old research station that had become buried under the ice over the last half-century or so. Hidden, crevasse-like holes above the crumpled buildings had created a hazard that station personnel had hoped to remedy with a few well-placed explosions to collapse the snow. Exerting a light ground pressure across its four wheels, Yeti was sent in to sniff out any remaining hazards with the GPR.

Smoky mountain seen through window.
Photo Credit: Peter Rejcek
Erebus volcano as seen through the helicopter cockpit.

On Erebus — where researchers have studied the volcano for 40 years under principal investigator Philip Kyle of New Mexico Tech External Non-U.S. government site — Yeti has an altogether different objective: Map out the steam-carved structures that riddle the slope around the volcano's crater.

The ice caves on Mount Erebus are attracting increasingly more scientific attention. It's not just volcanologists who are rappelling into this subterranean world to learn about such things as the volcano's chemical flatulence through fissures on its flanks. Biologists are interested in what sort of microbial life might exist in these discrete environments, which are much warmer and far more humid than the frigid, wind-sculpted surface.

In fact, the NSF has instituted a moratorium on entering the ice caves except for certain research purposes — and then only with strict environmental controls — in response to possible contamination. Scientists are currently developing long-term protocols for ice cave research.

http://antarcticsun.usap.gov/science/contenthandler.cfm?id=2818
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