 
World's Largest Land Vehicle
The Marion Power Shovel Company in Marion, Ohio,
in 1965 built the world’s largest land vehicle,
NASA’s Crawler
Transporter (CT). It played a key role in the Apollo program, which landed
Americans on the moon, and then tackled a new mission to help launch the space
shuttle fleet.
Bucyrus International acquired
the Marion Power Shovel Company in 1997.
 How do you move 12 million pounds worth of a
Saturn V rocket and its launching derrick 5 miles from an assembly building to
the launch pad? Oh, by the way, you’ve got to keep the rocket vertical while
negotiating a road with grades of 5 degrees.
NASA faced that problem in the 1960s, as the
Apollo program swung into full gear. The Saturn V rocket had to be enormous to
lift the 45-ton Apollo spacecraft on those historic earth orbital and lunar
missions from 1967 to 1972. Engineers would assemble the rocket in a
vehicle-assembly building located about 5 miles from the launch pad.
For the answer, NASA turned to
Marion, a company world famous since the late
1800s for building mammoth steam shovels and other
machines for digging and earth moving. The Ohio company built two identical
machines straight out of science fiction. The Crawler Transporter is 131 feet
long, 114 feet wide, weighs 6 million pounds, and rides on 4 double tracks, each
pair bigger than a school bus. Its two giant diesel engines crank out 8,000
horsepower. They drive electric generators that supply current for the
vehicle’s 16 electric motors, which move it at a top speed of 1-2 miles per
hour.
Fuel economy? About 42 feet per gallon, or 126
gallons per mile.
The Crawler Transporter, however, is both brawn and brains, with a sophisticated
automatic load-leveling system that keeps spacecraft level, despite slight dips
in the road.
Marion built the
behemoths in Ohio, and shipped them to the Kennedy Space Center (KSC) in Florida
for assembly. The Crawler Transporters carried all of the Apollo program rockets
to the launch pad, including Apollo 11, the first lunar landing mission in 1969.
Then they were modified for service in the space shuttle program.
KSC workers assemble the airplane-like shuttle
orbiter, external fuel tank, and solid rocket boosters inside a huge building.
Then the CT lifts the vehicle and its mobile launcher, and carries it to the
launch pad. The upgraded Crawler Transporters use a laser guidance system to
reach the launch pad, where they PLACE the Shuttle-topped mobile launcher onto the pad
pedestals. The CT then rumbles away to a secure parking site away from the pad
to avoid possible damage from launch.
If hurricane-strength winds move in, NASA
summons a CT to carry the shuttle back to the safety of the vehicle assembly
building. That return trip also may be necessary to repair problems with the
shuttle detected just before launch. After each launch, the Crawler Transporter
removes the mobile launcher from the pad so it can be refurbished.
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