Space shuttle Endeavour roared into orbit Wednesday on a flight to deliver new residents to the international space station, following nearly a week's delay.

The launch had been postponed first by thunderstorms, then by a leaky valve. The weather finally cooperated late Wednesday afternoon, and the shuttle and its crew of seven climbed through low, puffy clouds on their way to space.

It was welcome news to the three space station men, in orbit since December. They were passing 240 miles above the Indian Ocean near Australia, and out of communication, when Endeavour blasted off with their replacements.

The bulletin came 24 minutes later from Mission Control: "It's on its way."

"All right!" space station astronaut Daniel Bursch shouted as crewmate Carl Walz whooped in delight.

"I knew you would be happy to hear that," added Mission Control's Frank Culbertson, who commanded the previous station crew. "You have a lot to do yet. But you've done a great job up there, far exceeded what's been done before, and we're very proud of you."

Endeavour — their ride home — is due to arrive at the space station on Friday.

As a precaution against terrorists, fighter jets patrolled the no-fly zone around the launch pad until after Endeavour's liftoff. In addition, NASA shrouded the activities of the U.S., Russian and French astronauts and cosmonauts until they were climbing aboard their spaceship.

In mid-afternoon, a small plane that had taken off from a flight school was ordered out of the restricted area and instructed to land. The plane came no closer than 40 miles to the shuttle, Air Force officials said.

Just before liftoff, launch director Mike Leinbach apologized to shuttle commander Kenneth Cockrell and his crew for keeping them in Florida for an additional six days. "But everything's coming together now," Leinbach said. "Good luck and have a great flight."

"We'll do a good job for you," Cockrell promised.

Endeavour is carrying one American and two Russians who will become the fifth crew to live aboard the space station.

The fourth expedition team, Bursch, Walz and their Russian commander, Yuri Onufrienko, rocketed into orbit exactly six months ago Wednesday. They were supposed to return to Earth in mid-May, but their mission was extended when NASA added a robot-arm repair job to the Endeavour visit.

The shuttle crew will conduct three spacewalks next week outside the space station, the last one to replace a flawed wrist joint in the orbiting outpost's 58-foot arm.

By the time Endeavour's 12-day flight ends, Bursch and Walz will have set a U.S. space endurance record. Wednesday marked the crew's 182nd day in orbit.

Endeavour is due back on Earth on June 17.