The space shuttle Endeavour and its seven-member crew lifted off at 6:36 p.m. EDT Wednesday from NASA's Kennedy Space Center in Florida. The astronauts are on their way to the International Space Station for an assembly mission, designated STS-118.

"This is serious business we're in here," said Endeavour's Commander Scott Kelly to the shuttle launch director shortly before lift off. "I'm proud of your team for getting Endeavour ready to go fly. I'm also proud of my crew and the rest of the astronaut office for the competence and professionalism and consistently making something that is incredibly difficult look easy."

Kelly then added, "We'll see you in a couple of weeks, and thanks for loaning us your space shuttle."

Endeavour is scheduled to dock to the station on Friday. During the 11-day mission, the crew will add the Starboard 5 (S5) truss segment to the right side of the station's backbone. The segment will provide clearance between sets of solar arrays. The flight will include at least three spacewalks during which the astronauts will install a new gyroscope and external spare parts platform to the station.

Endeavour's mission will debut a new system that enables docked space shuttles to draw electrical power from the station to extend visits to the outpost. If this system functions as expected, three additional days and a spacewalk will be added to the flight.

Joining Kelly on the crew are Pilot Charlie Hobaugh and mission specialists Tracy Caldwell, Rick Mastracchio, Barbara R. Morgan, Alvin Drew and Canadian Space Agency astronaut Dave Williams. This is the first flight for Morgan, the teacher-turned-astronaut whose association with NASA began 22 years ago when she was selected as the backup in the Teacher in Space Project.

This mission is the 119th space shuttle flight, the 20th flight for Endeavour and the 22nd U.S. flight to the International Space Station. The mission is Endeavour's first flight in more than four years. The shuttle underwent extensive modifications, including the addition of safety upgrades already added to shuttles Discovery and Atlantis.