Three Mobile Launchers used in Apollo/Saturn operations were modified for use with the Shuttle. They transport the Shuttle from the Vehicle Assembly Building to the launch area. Three openings accommodate flames and hot exhaust gases from the solid rocket boosters and the orbiter engines. The launchers carry a weight (including the unfuelled Shuttle) of 5.45 million kg. Each of the three Mobile Launchers stood a massive 490ft. 6in. tall, from ground level to the high-point at the top of the lightning-mast. The structures consist of four main parts: the Hammerhead Crane on the top, the Launch Umbilical Tower (LUT), and the Mobile Launcher Platform which is two-story steel structure, 7.6 meters (25ft) high, 49 Meters (160ft) long and 41 meters (135ft)wide. To begin putting the Shuttle elements together, one of two Crawler Transporters must first move one of the three Mobile Launcher Platforms into the Vehicle Assembly Building. The crawler is one of the world’s largest moving land vehicles, weighing more than 3000 tons .

On the launch pad