One of robot Zoe's accomplishments during this year's field test in Chile's Atacama Desert was navigating autonomously for 200 kilometers, or roughly 124 miles.

But a month ago, five robotic vehicles, including two built by Carnegie Mellon's Red Team, seemingly left Zoe in the dust when they completed a 132-mile desert course near Las Vegas, Nev., in the Defense Advanced Research Projects Agency's $2 million Grand Challenge race.

The leading Grand Challenge racers finished the course in about seven hours; Zoe covered roughly the same distance in 30-35 days.

The difference in speeds, however, has more to do with the difference in tasks, rather than any difference in the level of accomplishment, noted Carnegie Mellon's David Wettergreen.

Unlike the Grand Challenge racers, which were following a predetermined path, Zoe was blazing its own trail, picking its way across the desert without a specified path or even a map.

"It's exploring," he said.

Though Zoe never went faster than four kilometers an hour, the robot managed to get where it was supposed to go without getting stuck. Even when the science team mistakenly sent Zoe over several miles of steep hills, the robot managed to avoid steep slopes that might have sent it tumbling as it clambered up and down the hills.