Americans have put machines on Mars before, but never one as big or ambitious as the SUV-sized Curiosity rover that touched down in GaleCrater in August. The landing, a live-streamed global event, was an improbable bit of daredevil flying. The descent pod came to a near-full stop a dozen or so yards above the surface, and the one-ton car was lowered on cables like an extraterrestrial marionette. Curiosity has two years of driving and investigating ahead of it, but just by getting where it was supposed to go in the first place it has marked itself a triumph.