It was a rare treat: The last time NASA launched a shuttle at nighttime was in 2006. Only about a quarter of shuttle flights have begun in darkness.
"Good luck and Godspeed, and we'll see you back here in 16 days," launch director Mike Leinbach radioed to the astronauts right before liftoff.
"God truly has blessed us with a beautiful night here, Mike, to launch, so let's light them up and give Him a show," replied Endeavour's commander, Dominic Gorie.
They did. The shuttle took flight with a flash of light, giving a peach-colored glow to the low clouds just offshore before disappearing into the darkness.
Gorie and his crew face a daunting job once they reach the international space station late Wednesday night. The astronauts will perform five spacewalks, the most ever planned during a shuttle visit.
The launching site was jammed with Canadians and Japanese representing two of the major partners in the international space station. The Canadian Space Agency supplied Dextre, the two-armed robot that was hitching a ride aboard Endeavour, while the Japanese Space Agency sent up the first part of its massive Kibo lab, a storage compartment for experiments, tools and spare parts.
Also on hand for the liftoff was a 19-member congressional delegation led by Rep. Nick Lampson, whose Texas district includes the Johnson Space Center in Houston. He is pushing for increased NASA funding.
For the first time since space station construction began nearly 10 years ago, all five major partners were about to own a piece of the orbiting real estate. The launch of the first section of Kibo, or Hope, finally propelled Japan into the space station action.
"Our Japanese people have been waiting for a very long, long time," said Yoshiyuki Hasegawa, the Japanese Space Agency's station program manager.
Preliminary design work for Kibo began in 1990. Space station construction, however, was stalled over the years for various reasons, most recently the 2003 Columbia tragedy.
The main part of the Kibo lab will fly on the next shuttle mission in May, with the final installment, a porch for outdoor experiments, going up next year.
Altogether, the Japanese Space Agency has invested about $6.7 billion in the space station program, including a Kibo control center near Tokyo.
Canada's $200 million-plus Dextre, meanwhile, is designed to eventually take over some of the more routine outdoor maintenance chores from spacewalking astronauts. Dextre, short for dexterous and pronounced like Dexter, will join the space station's Canadian-built robot arm, already in orbit for seven years.
In addition to working with their international payloads, Endeavour's astronauts will try out a caulking gun and high-tech goo on deliberately damaged shuttle thermal tile samples.
The test - part of NASA's ongoing post-Columbia safety effort - should have been performed last year, but was put off because of emergency space station repairs.
Astronaut Garrett Reisman will stay behind on the space station until June, swapping places with a Frenchman who accompanied Europe's Columbus lab into orbit in February.
A Japanese astronaut is also part of Endeavour's all-male crew.
It is the second of six planned shuttle missions this year, all but one to the space station. NASA faces a 2010 deadline for finishing the station and retiring its shuttles.