NASA’s two Mars rovers were busy through the long holiday weekend, one progressing toward a distant crater and the other digging a trench to expose material beneath the martian surface for study by geology instruments, mission officials said Tuesday. NASA, meanwhile, changed the leadership of the $820 million double-rover mission to allow project manager Pete Theisinger to join a new program aiming for a Mars launch in 2009. Deputy project manger Richard Cook will take over the rovers.