Shuttle on its way to space station

Space shuttle Endeavour roars into space Wednesday.

KENNEDY SPACE CENTER, Florida (CNN) -- After almost a week of delays, the space shuttle Endeavour beat the odds and lifted off Wednesday on its way to rendezvous with the International Space Station.

Earlier in the day, NASA and Air Force weather forecasters said there was a 60 percent chance weather would prohibit a takeoff Wednesday, but the clouds parted and the shuttle roared into orbit after a nearly flawless countdown.

Endeavour was originally scheduled to launch last Thursday. It was held back by two days of weather delays and two days of repairs on a leaky valve in one of the rocket motors that allows the orbiter to make key maneuvers in space.

Endeavour is carrying important relief supplies to the space station, along with a much needed relief crew. The Expedition Four crew, two Americans and one Russian, have been on board the station since December 7.

When the Expedition Four crew returns to Earth -- touchdown is scheduled for June 17 -- Carl Walz and Dan Bursch will have set a new space endurance record for American astronauts.

Their 193 days will surpass the previous record of 188 days set by Shannon Lucid on the Mir space station in 1996. Without the delays, her record would have stood by only a few hours.

CNN NewsPass VIDEO After almost a week of delays, the space shuttle Endeavour lifted off safely on its way to rendezvous with the International Space Station. CNN's Miles O'Brien reports (June 6) Play video Watch the launch of the space shuttle Endeavour (June 5) Play video   MISSION GUIDE Our CNN.com Endeavour mission guide  has crew bios, a mission timeline and more.

The Americans will remain well short of the Russian record of 438 days set by cosmonaut Valery Polyakov, also aboard Mir.

Lucid's mark will stand as the world endurance record for a woman in space.

The shuttle mission also will include three spacewalks to improve the performance of the Canada Arm.

On the first two spacewalks, scheduled for Sunday and Tuesday, astronauts Franklin Chang-Diaz and Philippe Perrin from France will install a system designed to carry the robotic arm across the length of the space station.

This step must be completed before the next shuttle mission to the space station, when astronauts are to use the arm and its mobile base to attach a new piece to the orbiting outpost.

In the third spacewalk, Chang-Diaz, who is on a record-matching seventh shuttle ride, and Perrin will install a new wrist joint on the billion-dollar robot arm. The current wrist is not as nimble as it was designed to be.

Endeavour's flight is the 18th for the orbiter and the 110th mission in the history of the space shuttle program.