Halfway to Mars

Out on the rocky horizon, the robot has stopped dead in its tracks. "Uh, Dave, I got a big problem out here," a voice crackles over the radio. "OK," David Wettergreen replies carefully, peering off in the direction of the machine. "Big" turns out to be a new part for the robot that doesn't quite fit and so prevents the robot's cameras--its eyes--from turning properly. Back at the laboratory, this would be a quick fix, but the robot, Wettergreen, three geologists, two software engineers, two sociologists, an electrical engineer, a mechanical engineer, and a biologist are all out in the middle of Chile's vast Atacama Desert, [see map] many hours' drive from civilization. As he strides off to investigate, you get the sense Wettergreen's enjoying himself. For the better part of an hour, he and two colleagues will wrestle with the aberrant part [see photo, " All in a Day's Work"].