CAPE CANAVERAL, Fla. — Last-minute rocket trouble forced SpaceX on Saturday to delay its inaugural launch from NASA’s historic moon pad. SpaceX halted the countdown with just 13 seconds remaining. The second-stage steering issue actually cropped up several minutes earlier. But with just an instant to get the unmanned Falcon rocket airborne, flight controllers could not resolve the problem in time. The next launch attempt – provided everything can be fixed quickly – would be Sunday morning. The Falcon remains at Kennedy Space Center’s Launch Complex 39A, waiting to soar on a space station delivery mission.