Canadian astronaut Chris Hadfield in training

The seven-strong crew includes the first European astronaut to visit the ISS, Italian astronaut Umberto Guidoni.

He joins four US colleagues, one Russian and one Canadian on the 11-day mission.

The seven astronauts arrived at Kennedy Space Center, Florida, on Monday, several hours before the countdown clocks began ticking.

The major objective of the mission is to install the space station's new 57-foot-long (17 metre) robotic arm, built in Canada.

The most advanced robotic device ever to be sent into space, it is designed to move itself about the station wherever it is needed.

The 'Big arm'

Can lift the weight of an entire space shuttle Each of its seven joints can rotate 270 degrees forward or backward Will be used to attach an airlock to the ISS and fit solar power panels

"The arm is absolutely critical in terms of being able to operate and assemble the station", said Tommy Holloway, Nasa's manager of the program. "Without it, we will not be able to complete the station."

Two spacewalks will be required to fit and connect the device.

Endeavour is also loaded with an Italian cargo carrier, named Raffaello after the 16th-century artist.

It will be the second of three Italian cargo carriers to be launched to the space station. Leonardo hauled up supplies last month.

Preparations

In preparation for Endeavour's arrival, the three residents of the space station undocked a Russian supply ship on Monday.

The Canadian-built robotic crane is known as the 'Big Arm'

The ship was loaded with rubbish and directed to burn up in the Earth's atmosphere.

Russian station commander Yuri Usachev and his US crewmates, Jim Voss and Susan Helms, have been living aboard the ISS since mid-March.

The shuttle crew is bringing them a two-month supply of food, spare parts for a broken treadmill and computer pieces.

There are also a few luxuries, including Canadian salmon and Italian parmesan cheese.