Space Shuttle Launch Delayed by Thick Clouds

As the sun rises over Launch Pad 39A at NASA's Kennedy Space Center in Florida, workers get ready to roll the rotating service structure away from space shuttle Endeavour in preparation for launch. CREDIT: NASA/Troy Cryder

This story was updated at 5:42 a.m. ET.

CAPE CANAVERAL, Fla. ? Thick clouds thwarted the attempted predawn launch of NASA?s space shuttle Endeavour on Sunday, forcing the orbiter?s six-astronaut crew to wait at least one more day before rocketing into orbit.

Despite early predictions of good weather, a thick layer of low-lying clouds crept in over NASA?s Kennedy Space Center here, preventing Endeavour?s planned 4:39 a.m. EST (0939 GMT) launch toward the International Space Station. The astronauts were already strapped inside their seats awaiting liftoff.

?We were just not comfortable with launching the space shuttle tonight so we?re going to go into a 24-hour scrub,? NASA launch director Mike Leinbach radioed Endeavour?s crew. ?Thank you all for the effort you all put in tonight.?

?You gave it a great try tonight. Sometimes you?ve got to just make the call,? Endeavour commander George Zamka replied. ?We understand and we?ll give it another try tomorrow.?

Endeavour is now slated to launch on Monday at 4:14 a.m. EST (0914 GMT, NASA test director Pete Nickolenko said after the launch attempt. There is a 60 percent chance of good weather predicted for Monday, NASA officials added.

The thick cloud layer for Sunday?s launch was hovering at about 3,800 feet above Endeavour?s launch sit. The layer was about 600 feet thick. It was a dynamic situation, with conditions wavering back and forth between acceptable and unacceptable for launch. At one point, Leinbach said he had never seen anything like the observed weather in his entire career as a shuttle launch director.

NASA?s space shuttle flight rules require cloud ceilings no lower than 4,000 feet and no thicker than 500 feet, Nickolenko said.

Endeavour?s six-astronaut crew plans to fly a 13-day mission to deliver a new room and observation deck to the International Space Station.

The mission is the first of NASA?s five final shuttle missions before retiring its aging space shuttle fleet later this year.

Endeavour has just one more chance to lift off (Monday?s opportunity) before NASA would stand down in order to launch the new Solar Dynamics Observatory ? a sun-watching probe ? atop an unmanned Atlas 5 rocket. That mission is now set to launch Feb. 10 from the Cape Canaveral Air Force Station near the Kennedy Space Center.

It takes about two days for NASA and the Air Force to turn around the Eastern Range they share for rocket and shuttle launches.

• Video - Endeavour's Mission: Space Windows and Rooms
• Video - Behind the Scenes of Endeavour's STS-130 Mission
• Images - Space Shuttle's Midnight Launch

SPACE.com is providing complete coverage of Endeavour's STS-130 mission to the International Space Station with Managing Editor Tariq Malik in Cape Canaveral and Staff Writer Clara Moskowitz in New York. Click here for shuttle mission updates and a link to NASA TV.