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Yeti was used to shake down the instruments Dartmouth plans on using on another mission with its other cold-weather robot, Yeti. sphere —respectively, a layer of upper at- second thing, of course, is that you want to “In the beginning we were envisioning a mosphere and a plume of charged particles use the least energy that you can to make very large panel that would face the sun, and how they interact with Earth’s magnetic this possible.” but that panel turned out to be much too field. The robot would traverse Antarctica during the austral summer and fuel itself off of solar power to survey the region. Ray says they started the Cool Robot project before they knew if a solar-powered cold weather robot “was even feasible.” Once large, and it would probably be more like a sail and probably flip the robot over,” Ray says. While this type work is easier to do at the the team set a target ground pressure, they For the power, the team took advantage of poles, the South Pole has added travel, set a mass budget so the robot would still the high reflection of the snow they knew expense and timing challenges for the stu- be functional on wheels. would be present. Without having any so- dents involved. The team for now is focused on Arctic exploration. Through a grant with the National Science Foundation, Dartmouth built a robot, called Cool Robot, and proved its viability. “Once you get into tracks you’re all of the sudden at a much higher energy budget.” To make the chassis, the team used Nomex, a Nylon-related polymer. With fiberglass plies on the outside and a honeycomb mid- To create a robot capable of operating over dle, the material can be used as airplane snow, the team focused on setting budgets floor panels. The team cut and folded the for its mass and energy. material into a box to create the chassis “In order to work in any terrain that’s de- and reinforced it with aluminum bracing. lar cells, Ray’s team roughed out on paper how much power it could get from a low sun angle with direct sunlight and reflection. “It turned out that the reflected piece was big enough that it made sense to make this solar panel into a box,” says Ray. The box would go over the top of the robot with panels on the sides and top. “Even if you have the sun directly on one of the panels, the formable, such as this, you’d like a low Then they had to tackle creating their own one opposite that in the back, even though ground pressure,” says Ray. “And then the solar panels. it’s in the shade, gets a decent fraction of Mission Critical • Winter 2011 15

Unmanned Systems Mission Critical - Winter 2011

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