Clouds ground space shuttle Endeavour

CAPE CANAVERAL - Chilly winds carried clouds over Cape Canaveral early Sunday morning, grounding space shuttle Endeavour for at least a day.

NASA had hoped to launch the shuttle on the first mission of the year at 4:39 a.m., but an early forecast calling for an 80-percent chance of good weather ultimately proved to be too optimistic.

Endeavour's six crewmembers were all strapped into their seats when the launch was called off. They're waiting to start a 13-day mission that should largely complete the construction of the international space station.

Endeavour will deliver Tranquility, the last major module to the station – one that includes a unique seven-windowed cupola that will give astronauts a 360-degree view of the station and spacecraft. A variety of supplies and other pieces of equipment are also hitching a ride aboard the shuttle.

The mission will be the first of what should be the last year of space shuttle operations. NASA is planning to retire the fleet; only four more flights remain on the schedule after this Endeavour mission.

According to NASA's current schedule, this flight will be the last shuttle launch to occur at night.

The agency will try again early Monday morning.