Florida ? Seven astronauts returned to NASA’s launch site Monday to take a new shot at flying space shuttle Atlantis to the international space station.

Liftoff is set for Thursday afternoon, with NASA wrapping up a last repair Sunday night involving a radiator hose. The mission was waylaid in December by a different problem, erratic fuel gauges.

Atlantis will carry the European Space Agency’s science lab, Columbus, to the orbiting outpost. That will be the second science lab – the United States operates one there already. The largest lab of all, Japan’s Kibo, or Hope, will be carried up in sections beginning next month.

Atlantis’ mission, fraught for weeks with mechanical problems, now faces only weather concerns, NASA officials said.