split image of nasas crawler transporter 2

Few vehicles are as popular as NASA’s Crawler-Transporter 2.

But what makes this vehicle special isn’t just it’s appearances in the films Apollo 11, Apollo 13 and Transformers: Dark of the Moon, but the fact that it’s the world’s heaviest self-powered vehicle

Weighing in at 3,106 tonnes (6.65 million Ib), the astronomical vehicle weighs about as much as 1,000 pickup trucks. 

Operated by NASA’s Exploration Ground Systems programme at the Kennedy Space Center in Florida, USA, CT-2 was designed to carry rockets from NASA’s Vehicle Assembly Building to the launch pad.

“Before we can launch, we must crawl. There is no NASA launch from Pad B without a Crawler-transporter,” said Daniel Zapata, NASA’s systems engineer.

“The Crawlers are a feat of mechanical, electrical, and structural engineering and a modern American marvel to behold.”

The next time the colossal CT-2 is expected to carry the mobile launcher and Artemis Moon Rocket to and from the launch pad, it will boast its new award. 


On 29 March 2023, Guinness World Records presented the CT-2 with a certificate for its 60th birthday ceremony. 

Crawler-Transporter 2 is one of a pair of giant tracked vehicles built by the Marion Power Shovel Company for NASA between March 1963 and January 1966. 

Their original purpose was to carry the Apollo Program's Saturn V rockets and their mobile Launch platforms the roughly 4 miles (6.7 km) from the Vehicle Assembly Building to either launch pad 39A or 39B.

The CT-2 was later upgraded to ensure it could lift and carry the heavier weight of the newer generation SLS Moon rockets. 


These upgrades included replacing the two massive locomotive engines that provide power to the four sets of caterpillar tracks and strengthening various other systems.

“Crawlers were originally designed in the 1960s to move the Saturn V rockets to the Launch Pads. Then, they served the Shuttle program for over 30 years, and now they have been modified to support Artemis,” said Daniel.

“With good maintenance and regular operations, the Crawler will last a very long time and support throughout the Artemis program.”

Not only did the upgrades add more weight to CT-2, but it made it making it heavier than its sibling, Crawler-Transporter 1. 

Crawler-Transporter 2 is 131 ft long and 114 ft wide (39.9 x 34.7 m; about the size of a baseball infield). 


The height is variable (it has a hydraulic levelling system that can raise, lower, and tilt the top deck) but maxes out at 26 feet (7.92 m). 

It is not designed to carry rockets directly, but rather to carry the mobile launcher platforms they are sitting on. 

These platforms are locked into place at the launchpad, and the Crawler-transporter withdraws back down the crawlerway some days before the launch takes place.

There are larger land-based vehicles, most notably the TAKRAF Bagger 293 bucket-wheel excavator, but these vehicles require an external power source to function. 


The Crawler-transporters generate all their own power using a set of locomotive diesel engines. 

“The crawler uses two 16-cylinder ALCO diesel engines which are each connected to two 1,000 KW DC generators,” said Daniel. 

“These generators provide electrical power to turn 16 DC propel motors, which moves a large gearcase assembly that moves the sprockets that pulls and pushes the Crawler shoe belt, creating movement. The Cab driver controls the speed of the Crawler using a speed potentiometer in the Cab.”

Crawler-Transporter 2 has a theoretical maximum speed of 2 mph (3.2 km/h) unloaded, but NASA engineers have never tried pushing it that hard.

Because of the heavy weight it has to carry, the 4.2 mile (6.7 km) trip from the Vehicle Assembly Building to pad 39B can range anywhere from weight to 12 hours, with CT-2 traveling at about one mile per hour. 

There are some improvements planned for CT-2, including 456 new re-designed CT shoes for increased lifespan before changeouts, steering cylinder changeouts, and ALCO genset refurbishments for improved reliability and maintaining critical assets.


Daniel says having CT-2 recognized by Guinness World Records is a huge honour and privilege and in the future he hopes to see it supporting manned Artemis missions to the moon, including moving the SLS rocket and Orion to its Launch Pad.

Eventually, he also hopes to see it moving the first rocket destined to Mars with astronauts.

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