After two months of delay, shuttle Atlantis blasted off Thursday with Europe's gift to the international space station, a $2 billion science lab named Columbus that spent years waiting to set sail. Atlantis and its seven-man crew roared away from their seaside launch pad at 2:45 p.m., overcoming fuel gauge problems that thwarted back-to-back launch attempts in December. The same cold front that spawned killer tornadoes across the South earlier in the week stayed far enough away and, in the end, cut NASA a break. All week, bad weather had threatened to delay the flight, making liftoff all the sweeter for the shuttle team. The sky was cloudy at launch time, but rain and thunderstorms remained off to the west.