The U.S. space shuttle Endeavour lifts off on Wednesday evening from Kennedy Space Center in Florida after five delays, on a track to the International Space Station (ISS).

Space shuttle Endeavour lifts off on a mission to the International Space Station from Cape Canaveral, Florida, July 15, 2009.[Xinhuanet.com]

According to NASA TV, Endeavour blast off at 6:03 p.m. EDT (2203 GMT). After two minutes and five seconds, the twin solid rocket boosters assisting Endeavour's launch into space were separated as planned from the shuttle's external tank.

The reusable boosters then fell back toward the Atlantic Ocean, where they will land under parachutes and be retrieved by recovery ships.

The rocket engines boosting Endeavour and its external tank towards orbit shut down as planned about eight and a half minutes into flight.

"The weather is finally cooperating, so it is now time to fly," launch director Pete Nickolenko called out to the crew ahead of the launch. "Persistence pays off."

The astronauts will dock with the ISS on Friday, which was soaring more than 220 miles above the Pacific at launch time. When they do, it will be the first time 13 people are together in space.

Space shuttle Endeavour lifts off on a mission to the International Space Station from Cape Canaveral, Florida, July 15, 2009.[Xinhuanet.com]

Endeavour should have blasted off to the ISS in mid-June, but was postponed for two times by potentially dangerous leaks of hydrogen gas. Lightning and thunderstorms have also foiled three earlier scheduled launches.

Endeavour's last attempt to blast off on Monday was abandoned minutes before launch because lightning and thunderstorms moved in near the launch pad and the Shuttle Landing Facility, required to be clear in case it's needed for an emergency landing shortly after launch. Mission managers decided not to try a launch on Tuesday to avoid predicted bad weather and to allow ground crews to replace a small thruster cover on the shuttle's nose that came unglued.

Endeavour commander Mark Polansky is leading a crew of seven space flyers that includes Canadian Julie Payette and NASA astronauts Doug Hurley, David Wolf, Chris Cassidy, Thomas Marshburn and Tim Kopra on the mission. Kopra is making a one-way trip to the station to replace Koichi Wakata of the Japanese Aerospace Exploration Agency as an Expedition 20 flight engineer.

Endeavour's 16-day mission will feature five spacewalks and complete construction of the Japan Aerospace Exploration Agency's Kibo laboratory. Astronauts will attach a platform to the outside of the Japanese module that will allow experiments to be exposed to space during the first spacewalks.

Space shuttle Endeavour astronaut Dave Wolf gives a thumbs-up from the white room as he prepares to board the orbiter in hopes that the shuttle will launch on its sixth attempt in this image from NASA TV July 15, 2009.[Chinadaily.com.cn via agencies]

(Xinhua News Agency, Chinadaily.com.cn July 16, 2009)