GROVER who? Curiosity might steal the rover limelight, but NASA's earthbound wanderer is also on a mission. Built to study the Greenland Ice Sheet, GROVER had to prove it could survive the harsh environment. Earlier this week, it passed its first Arctic test on Greenland's highest spot.
Enduring temperatures down to -22 degrees Fahrenheit and gusts of 30 miles per hour, GROVER—short for Greenland Rover and Goddard Remotely Operated Vehicle for Exploration and Research—was tested May 6 to June 8 at Summit Camp, a research station at the tallest point of the Greenland Ice Sheet. Even though it was GROVER's first polar experience, the robot successfully confirmed it could execute commands sent over an Iridium satellite connection. GROVER also demonstrated that it could transmit real-time information about its system performance.
GROVER originated as a student project, part of NASA's engineering boot camp during the summers of 2010 and 2011 at the Goddard Space Flight Center in Greenbelt, Md. Back in the summer of 2012, rising temperatures led to extreme melting across 97% of the ice sheet, so the students built a rover to detect the melt layer and estimate its thickness. With all-day sunlight, a solar-powered rover would be more efficient than using radar via snowmobiles, airplanes or satellites. Prior to the Greenland assessment, the 800-pound rover was tested on the snow in Idaho and beach in Maryland.
"We didn't have any major performance problems with GROVER, but every once in a while a component would fail due to the temperature," said Gabriel Trisca, a Boise State University graduate student involved with the GROVER project since the summer of 2010. He noted that the weather deteriorated the robot's plastic components, wires and connectors.
Watching GROVER take off (albeit at a paltry 1.2 miles per hour) was "like seeing a baby make its first steps," he said.
While GROVER showed it could survive Greenland's extreme conditions, its solar-powered batteries didn't last as long or recharge as quickly as expected because of the weather. Researchers plan on altering other components as well. Possible changes include merging two onboard computers to save energy, using wind generators to create energy, and switching to a geostationary satellite connection.
"While we learned many lessons on how to make GROVER even more resilient to the cold, we will make substantial improvements in the serviceability of the components, to allow for hot swapping of parts, have built-in redundancy for crucial components, and an even more comprehensive diagnostics system that replaces the current one," Trisca added.
Researchers will continue to test GROVER's software and mechanics until the winter. At that point, it will head to a local ski resort for more field testing. The plan is for GROVER to return to Summit Camp next summer.
[Image: NASA Goddard/Matt Radcliff]