KENNEDY SPACE CENTER -- Mission managers say it does not look good for a shuttle launch this week, and they expect to roll the orbiter back to its assembly building Tuesday

NASA blames the prospect of tropical storm-force winds near the Kennedy Space Center for scrubbing Tuesday's planned liftoff.

And the shuttle launch director says "unless something really extraordinary happens," engineers will start moving Atlantis back into its assembly building Tuesday morning.

With Tropical Storm Ernesto whirling about on a potential course that spans much of Florida, the weather officer said officials are "even more concerned" about the storm's track now.

Without a rollback, NASA could try for a lift-off over the weekend. But if the shuttle crawls back inside, it will take at least eight days to get ready for another launch try.

The National Hurricane Center said Ernesto may be a hurricane again and spinning almost directly over the Kennedy Space Center by late Wednesday. NASA doesn't want the shuttle on the launch pad if winds are greater than 45 mph.

The launch window for the space station-building mission closes after Sept. 7.

A crew of six will conduct the first construction on the international space station since the Columbia disaster in 2003. The mission includes installing additional solar panels on the orbiting outpost that will double its power.

The mission has been called one of the shuttle program's most challenging.