LOS ANGELES - Spirit, the mountaineering rover that successfully scaled a Martian hill this summer, is searching for flatter ground. After two months at the summit of Husband Hill, the six-wheeled rover is making its descent toward a basin to the south where it will explore an outcrop dubbed "home plate" that looks like a baseball diamond from orbit. The solar-powered Spirit's yearlong climb to the peak marked a major feat for the rover, which along with its twin, Opportunity, landed on opposite ends of the Red Planet in 2004 in search of evidence of the past history of water...
