The structure of the reference the same track basic parameters of the crawlertractor, design the structure and size of crawler, make whole design are optimized.
履带的结构同样参考了履带拖拉机的基本参数，设计了履带的结构和尺寸，使整个设计得到了优化。
2
Bathed in xenon spotlights, the white spaceship, attached to its twin solid rocket boosters and orange external fuel tank, crept 3.4 miles on the back of an enormous tractor called the Crawler.