The space shuttle Endeavour bolted off its seaside launch pad on Monday on a voyage to install the last two main pieces of the International Space Station.
The 4:14 a.m. EST (0914 GMT) blastoff from the Kennedy Space Center shattered the predawn tranquility with a deafening roar and a brilliant tower of flames that momentarily turned the dark Florida sky as bright as day.
Low clouds forced NASA to postpone Endeavour's first launch attempt on Sunday morning. Scattered clouds also threatened visibility on Monday but cleared in time to meet flight safety rules.
The shuttle carries the station's last connecting hub and a dome-shaped cupola with seven windows to provide the crew with panoramic views outside the station.
The modules were built in Italy for NASA and will complete U.S. assembly of the orbital outpost, a $100 billion project of 16 nations that has been under construction since 1998.
Four more shuttle missions remain to deliver cargo platforms, spare parts and experiments before the fleet is retired later this year.
"Every launch is a little bittersweet," said Mike Moses, a shuttle program manager at the Kennedy Space Center. "We're one closer to the end."
The Endeavour crew includes commander George Zamka, pilot Terry Virts, flight engineer Stephen Robinson, spacewalkers Robert Behnken and Nicholas Patrick and mission specialist Kay Hire. The shuttle is scheduled to reach the station on Wednesday for a nine-day stay.