A modified Boeing 747 with the shuttle mounted on its back touched down at Fort Campbell on the Kentucky-Tennessee state line around 9:30 a.m. CDT after leaving Offutt Air Force Base in Nebraska.
The refueling stop at Fort Campbell will last until weather clears in Florida, but the jet's itinerary remains confidential for security reasons until it's in the air. The jet stops at several undisclosed locations for refueling.
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The shuttle could still arrive at Cape Canaveral on Monday as planned, but a Tuesday arrival was possible if bad weather intervened, NASA spokeswoman Jennifer Tharpe said.
"They aren't going to rule it out," Tharpe said. "There's so many things playing into it."
Fort Campbell officials said the shuttle could be grounded through the Fourth of July. A shuttle stopped in Fort Campbell once before, when it stayed about four days in September 1998 waiting for weather to clear in Florida, authorities said.
The jet stopped Sunday for refueling in Amarillo, Texas, making an unusual stop on a commercial runway. Amarillo is about 500 miles south of Offutt.
Atlantis, carrying seven astronauts, landed June 22 after a 14-day construction mission at the international space station.
Bad weather at the Florida launch site forced NASA to divert to the shuttle's alternate landing site in California. NASA prefers to land shuttles in Florida to avoid the nearly $1.5 million price tag to transport them back.