A single crawler tread shoe was used on NASA’s enormous Crawler-Transporters, which moved Apollo spacecraft, the Skylab space station, and other space shuttles to the launch site at the Kennedy Space Center in Florida. Designed and built by Marion Power Shovel, the two Crawler-Transporters were the most massive vehicles made. One of the Crawler’s unique features was its giant tracks, with eight treads, two at each corner, and each track containing 57 shoes. Each shoe was 7.5 feet long, 1.5 feet wide, and weighed 12,100 pounds. The complete crawler weighed 16 million pounds and could carry a load of 6,000 tons. When a rocket was loaded onto the Crawler, it was mounted vertically on the launch assembly and transported by the Crawler to the launchpad.