WASHINGTON (PTI): Low cloud ceiling over Kennedy Space Center in Florida this Sunday forced NASA to postpone the launch of U.S. space shuttle Endeavour by at least one day.

Launch managers initially plan for a 24-hour turnaround, but will evaluate coming Monday's weather before making a final decision.

The new launch time has been scheduled at 4:14 am EST (1444 IST).

"We tried really, really hard to work the weather. It was just too dynamic," launch director Mike Leinbach told the six astronauts aboard Endeavour. "We just were not comfortable with launching the space shuttle tonight."

Endeavour has been scheduled to lift off today, on a 13- day construction mission to the orbiting International Space Station (ISS).

Endeavour's mission will deliver and assemble Node 3, the last U.S. module, onto the ISS, giving the laboratory a room with quite a view.

The mission will kick off the final year of shuttle flights, with five missions planned through September.

It is expected to be the last shuttle launch in darkness.