After a two-day delay because of weather conditions, NASA managers gave the go-ahead early Wednesday for the space shuttle Endeavour to begin its cross-country flight from Kennedy Space Center in Florida to Los Angeles, where the now-retired spacecraft will be put on display.
The shuttle is scheduled to depart at 7:15 a.m. EDT, although "lingering showers may delay takeoff slightly," according to an announcement over Kennedy's PA system.
NASA had postponed Endeavour's piggyback trek atop a modified 747 airliner to its retirement home after inclement weather Monday and a poor forecast Tuesday.
The journey is divided into three legs that could be described as scenic routes to showcase the shuttle to the public. It will take three days to complete.
Endeavour, along with Discovery, Enterprise and Atlantis, became museum pieces after NASA ended its 30-year shuttle program on July 21, 2011.
Two other shuttles -- Challenger and Columbia -- were destroyed in tragic accidents, costing the lives of all on board. Challenger exploded shortly after launch, while Columbia broke apart upon reentry into Earth's atmosphere.
NASA expects Endeavour to draw crowds of onlookers as the jumbo jet carrying it plots a course over space centers in at least five states and makes stops along its way to Los Angeles, where it ends its trip Friday.
The flying duo will dip to about 1,500 feet at many points along the way, to afford a better view of the retired shuttle to spectators on the ground.
"Social media users are encouraged to share their Endeavour sightings using the hashtags #spottheshuttle and #OV105, Endeavour's orbiter vehicle designation," NASA said in a news release.
Wednesday's leg of the journey takes Endeavour to Houston, with flyovers along Florida's Space Coast, Stennis Space Center in Mississippi and the Michoud Assembly Facility in New Orleans.
On Thursday, Endeavour flies over the White Sands Test Facility in New Mexico on its way to Edwards Air Force Base outside of Los Angeles.
On Friday, it embarks on a tour of the state's north, dipping over NASA's Ames Research Center, Sacramento and San Francisco before heading back to Los Angeles, where Endeavour will be an exhibit at the California Science Center.
Named for the first ship commanded by British explorer James Cook, Endeavour rolled out of the assembly plant in Palmdale, California, in 1991 at a cost of $1.7 billion. It was the baby of the shuttle fleet, built as a replacement for the ill-fated Challenger, which tore apart less than two minutes after liftoff in January 1986.
Over the next 20 years, Endeavour flew some of the most high-profile shuttle missions in history, covering 25 flights and nearly 123 million miles. It flew a spacelab mission and numerous International Space Station assembly missions and also rendezvoused with Russia's Mir Space Station.
CNN's Ric Ward contributed to this report.
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