Road hazards threaten rover

摘要

John Grotzinger, the project scientist for NASA's Curiosity rover, is eager to study the rocks on Mars. But right now he fears them. "Today the rover planners were so tense that they only agreed to drive 10 meters," he says. "It's killing us." The problem: Daggerlike rocks are tearing into Curiosity's featherweight aluminum wheels. The rover has been returning increasingly alarming pictures of punctures in the metal, which is just 0.75 millimeters thick, and scientists and engineers both on and off the team are concerned. Even Alcoa, one of the world's largest aluminum producers, has offered suggestions for minimizing the damage, says Grotzinger, a planetary scientist at the California Institute of Technology in Pasadena. "I've got a nation of back-seat drivers," he says.