The shuttle is scheduled to launch from 1 to 19 July

The slow procession from the Vehicle Assembly Building to the pad took almost eight hours.

The space shuttle is scheduled to fly some time between 1 and 19 July.

It will be only the second shuttle flight since the space shuttle Columbia disintegrated on re-entry three years ago, killing all seven astronauts.

Pointing skywards, the shuttle, already attached to its orange rocket fuel tank and two solid rocket boosters, inched along its four-mile (6.5km) journey atop a giant transport vehicle.

Shuttle programme manager Wayne Hale has expressed confidence that Discovery will launch in July as planned and that the US space agency (Nasa) will be able to launch a further two shuttle flights before the end of the year.

A final decision on whether to launch will be made in mid-June.

Discovery had originally been expected to blast off this month, but the schedule was changed when a faulty fuel tank sensor was discovered.