Earth’s poles are the wheeling grounds for two polar rovers: solar-powered Cool Robot and its younger cousin Yeti.

The pair, designed by a team led by engineer Laura Ray at Dartmouth College, are among the first autonomous polar robots to go to work. Now, knee-high Yeti is on an expedition to Antarctica, peering beneath the ice and snow on Mt. Erebus, in search of steam-carved caves hiding in the volcano’s ice cap.

“The idea was that we should have terrestrial robots — rovers that can do science missions much like planetary rovers,” said team member James Lever, an engineer at the U.S. Army Cold Regions Research and Engineering Laboratory. “They can be less expensive. It’s not quite as harsh as a planetary mission. But it’s still pretty demanding.”

Lever shared an update on the robots’ activities Dec. 4 at the American Geophysical Union, the day after the bots’ bigger, interplanetary cousin Curiosity took center stage at a press spectacle.

First deployed in 2005, Cool Robot was designed to help science teams working at the ends of the Earth. Because the rover needs to be able to work for long periods of time, the team decided Cool Robot should be solar powered. Enclosed in a box of solar panels, Cool Robot is able to feed off the sun and can cover more than 300 miles in a week. “The only restriction is that you do summertime science, but the advantage is that the sun’s up 24 hours a day,” Lever said. The robot’s solar panels are designed to capture as much sunlight as possible – even the bits bouncing off the bright white northern ice, which contribute about one-third of the rover’s power.

Next year, the 130-pound Cool Robot will return to Greenland, its preferred work place and one it’s visited many times. In June, the robot will begin mapping the snow’s surface features and roughness, providing data from the ground that can be compared with satellite observations. It’ll also measure the emissions footprint of Summit Station, a National Science Foundation research outpost parked atop the Greenland ice cap at 10,530 feet elevation. “We’ll circumnavigate the summit and get the emissions footprint. As often as we can. Until we get thrown out,” Lever said.

Yeti, completed in 2008, is a 180-pound, radar-enabled, battery-powered robot. More worldly than Cool Robot, Yeti has seen both the snows of the Arctic in Greenland, and the Antarctic at South Pole and McMurdo Stations. “Yeti was a bit more purpose-built,” Lever said. “This one was designed to do ground-penetrating radar surveys to detect crevasses.”

Snow covered and deep, crevasses hiding from view are hazardous to teams toting heavy loads of science equipment. GPS-guided Yeti travels ahead of heavier vehicles and uses its radar, housed in an inner tube, to help teams avoid the dangerous cracks. So far, Yeti has peered beneath the sheets in Greenland and Antarctica and will soon be helping researchers map the crevasse-riven area separating the McMurdo and Ross ice shelves, a key crossing for research teams in the Antarctic.

In December 2011, Yeti helped researchers study the buried remains of the original South Pole station, a collection of buildings built in 1956. Abandoned in the 1970s, “Old Pole” now lies under roughly 30 feet of snow. Yeti’s job was to find out if any of the buildings were still intact, creating voids that are hazardous to people on the surface above. “If the structures are collapsed under the weight of the snow, they’re OK as is,” Lever said. If not, it could be crushed by machinery trundling along above it. Yeti’s studies show that despite demolition by explosives in 2010, some of the buried buildings appear to be intact.

Now, Yeti has returned to Antarctica, where it will be joining an 11-person team studying Mt. Erebus, Earth’s most southern active volcano. Until January, the robot will be looking for hidden ice caves formed by fumaroles, vents that send hot vapors and gases into the surrounding ice. Using a machine-learning approach, Dartmouth graduate student Rebecca Williams is also teaching Yeti how to analyze the crevasse-finding radar images, rather than sending the data to a human for processing.

In the future, scientists hope autonomous polar robots will be able to substantially contribute to research projects at the poles, perhaps by deploying and maintaining a network of space weather sensors – which need continual repositioning in response to shifting solar storms – or by studying glaciers and icy terrains.