Crawler-transporter
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The crawler-transporter is a tracked vehicle used to transport the Saturn V rocket, the Saturn IB rocket during Skylab and Apollo-Soyuz Test Project, and now the Space Shuttle, from NASA's Vehicle Assembly Building to the Launch pad on a Mobile Launcher Platform. The crawler-transporter, built by the Marion Power Shovel Co. at a cost of $14 million, was once the largest tracked vehicle in the world; it has since been surpassed by the German Bagger 288 excavator.
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[edit] Specifications
The crawler-transporter has eight tracks, two on each corner; each track has 57 shoes, and each shoe weighs approximately 900 kg (about one short ton). It measures 131 feet by 114 feet (40 m by 35 m); the height from ground level to the platform is adjustable from 20 to 26 feet (6 to 8 m). The transporter weighs 6 million pounds (2,700 t).
It is powered by 16 traction motors, powered by four 1,000 kW generators, driven by two 2,750 hp (2050 kW) diesel engines. Two 750 kW generators, driven by two 1,065 hp (794 kW) engines, are used for jacking, steering, lighting, and ventilating. Two 150 kW generators are also available to power the Mobile Launcher Platform. The crawler consumes 150 US gallons of diesel fuel per mile (350 L·km−1); its tanks hold 5,000 US gallons (19 m³).
The maximum speed of the crawler-transporter is about one mile per hour (1.6 km·h−1) loaded, or two miles per hour (3 km·h−1) unloaded; average trip time from the Vehicle Assembly Building to the launchpad is between five and eight hours. Pad A is 3.5 miles (5.6 km) from the VAB, Pad B is 4 miles (6.4 km). It is controlled from two control cabs located at either end of the vehicle. The shuttle is moved to the launchpad on the Crawlerway, which is 3.5 miles long.
In order to keep the rocket from toppling over, the tip is kept vertical within plus or minus 10 minutes of arc. Leveling systems within the crawler also keep the platform level while negotiating the 5% ramp leading up to the pad surface. The crawler travels along a "road" which had to be specially packed to withstand the forces put on it.
Kennedy Space Center has been using the same two crawlers since their initial delivery in 1965; the pair are named "Hans" and "Franz" after the Saturday Night Live skit Hans and Franz. In their lifetime they have travelled some 2,500 miles (4,000 km) or more. NASA will continue to use the crawlers when the Space Shuttle is retired in 2010 and the Ares I and Ares V take its place, but due to their age and need to support the heavier Ares V vehicle and its launch umbilical tower, NASA will most likely retire the two crawlers and replace them with units identical in apperance, but with the ability to carry the heavier loads envisioned with the Ares V for both its lunar, and later planetary roles.
[edit] Crawler in popular culture
In an interesting coincidence, the giant moon rocket from the 1929 Fritz Lang film Frau im Mond (Woman in the Moon) is shown leaving a building similar to what would become the Vehicle Assembly Building and transported to the launch pad on a vehicle similar to what would become the crawler-transporter.
[edit] Sources
[edit] External links
- WikiSatellite view of Crawler at WikiMapia
- Apollo Maniacs: Crawler Transporter
- Kennedy Space Center Crawler/Transporter Model, a LEGO reconstruction of the crawler
