Endeavour fixed and ready to go

Space shuttle Endeavour was built to replace the Challenger ship which was lost on launch in 1986

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The American shuttle Endeavour will try again on Monday to launch to the International Space Station (ISS).

Engineers believe they have fixed a heater problem in the aft of the ship that kept the orbiter from making an ascent two weeks ago.

Endeavour is undertaking its final mission before retirement to a Los Angeles museum.

It will carry to the ISS a $2bn particle physics experiment known as the Alpha Magnetic Spectrometer (AMS).

Also in the shuttle's payload bay will be a tray of critical spare parts for the station.

"Endeavour is pretty close to my heart as it's the first space shuttle I flew on in 2001," said shuttle commander Mark Kelly. "So I'm glad it's the one I'm going to fly in last.

"It's the baby of the fleet; it's coming up on 19 years in service - the 25th flight. Twenty-five is a good round number to end on."

Lift-off from the Kennedy Space Center in Florida is timed for 0856 local time (1256 GMT; 1356 BST).

Local police say they expect perhaps half a million people to gather around the spaceport to try to get a good view of the orbiter climbing into the morning sky.

Among those expected to attend is Arizona congresswoman Gabrielle Giffords, who is recovering from a gunshot wound to the head.

On the ship's return, the only active orbiter left in the US space agency's (Nasa) shuttle fleet will be Atlantis.

It should make a final sortie sometime in July.

Endeavour's last flight will be historic on many fronts, not just because it is the orbiter's swansong:

Its cargo will be the single most expensive science experiment to be delivered to the ISSThe mission is expected to see a shuttle crew make a spacewalk for the last timeItalian crewmember Roberto Vitorri will be the last non-American to fly aboard a shuttleAnd it will see mission specialist Mike Finke become the most experienced American astronaut in history. On his return, Finke's cumulative time spent in orbit will be 381 days, passing that of Peggy Whitson.

SPACE SHUTTLE ENDEAVOUR

Endeavour was the last orbiter to be built and flew its maiden voyage on 7 May, 1992It is named after the ship commanded by the British explorer James Cook from 1769 to 1771Total space time to date: 280 days; Total Earth orbits: 4,429; Individual crew members: 133Made the first American ISS construction flight, delivering the Unity ModuleCarried out the mission to correct the Hubble Space Telescope's flawed visionIts radar map of the planet is one of the most used Earth-observation data-sets ever acquired

The delayed arrival at the station means the sleep patterns of the shuttle's crew members and those of the station's residents will be slightly misaligned.

The daily routine for the Endeavour crew will begin rough