Clear weather allowed a jumbo jet carrying the space shuttle Atlantis to take off Monday for Kentucky on its way back to Kennedy Space Center in Florida, NASA said.
NASA officials decided the shuttle could leave Offutt Air Force Base following an early morning weather briefing, spokeswoman Jennifer Tharpe said.
"We're really ready to get where we're going," Tharpe said before takeoff.
A modified Boeing 747 with the shuttle mounted on its back left from Edwards Air Force Base on Sunday morning and landed at Offutt that afternoon following a refueling stop, officials said.
The jet's destination remained confidential until it was in the air for security reasons. It was to land at Fort Campbell, Kentucky, for refueling, 1st Lt. Matthew Miller with Offutt said.
The jet, which stops to refuel at undisclosed locations, could still arrive at Cape Canaveral on Monday as planned, but a Tuesday arrival was possible if bad weather intervened, Tharpe said.
"They aren't going to rule it out," Tharpe said. "There's so many things playing into it."
The jet made a refueling stop earlier Sunday in Amarillo, Texas, making an unusual stop on a commercial runway. Amarillo is about 500 miles (804.6 kilometers) south of Offutt.
Atlantis, carrying seven astronauts, landed June 22 after a 14-day construction mission at the international space station.
Unfavorable weather at its 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 cost of transporting them back.