Crawler-transporter - Specifications

Specifications

The crawler-transporter has a mass of 2,721 tonnes (2,721,000 kg; 6,000,000 lb) and has eight tracks, two on each corner. Each track has 57 shoes, and each shoe weighs 1,984 pounds (900 kg). The vehicle measures 131 by 114 feet (40 by 35 m). The height from ground level to the platform is adjustable from 20 to 26 ft (6.1 to 7.9 m), and each side can be raised and lowered independently of the other. The crawler uses a laser guidance system and a leveling system to keep the Mobile Launcher Platform level within 10 minutes of arc (about 1 foot (30 cm) at the top of the Saturn V), while moving up the 5% grade to the launch site. A separate laser docking system provides pinpoint accuracy when the crawler-transporter and Mobile Launch Platform are positioned in the VAB or at the launch pad. A team of nearly 30 engineers, technicians and drivers operate the vehicle.

The crawlers were overhauled in 2003 with upgrades to the Motor Control Center, which houses the switchgear and electrical controls of all of major systems on board, a new engine and pump ventilation system and new diesel engine radiators, and replacement of the two driver cabs on each vehicle (one on each end). As of 2003, each crawler had 16 traction motors, powered by four 1,341 horsepower (1,000 kW) generators, in turn driven by two 2,750 horsepower (2,050 kW) V16 Alco diesel engines. Two 1,006 horsepower (750 kW) generators, driven by two 1,065 horsepower (794 kW) engines, were used for jacking, steering, lighting, and ventilating. Two 201 horsepower (150 kW) generators were also available to power the Mobile Launcher Platform. The crawler's tanks held 5,000 US gallons (19,000 l; 4,200 imp gal) of diesel fuel, and it burned 125.7 US gal/mi (296 l/km; 104.7 imp gal/mi).. Due to its age and the need to support the Space Launch System's heavier Ares V and its launch tower, in mid 2012 one of the crawlers was undergoing an upgrade involving "new engines, new exhausts, new brakes, new hydraulics, new computers,” to increase its lifting capacity from 12,000,000 pounds (5,400,000 kg) to 18,000,000 pounds (8,200,000 kg).

The crawler is controlled from two control cabs located at either end of the vehicle, and travels along the 3.5 miles (5.6 km) crawlerway at a maximum speed of 1 mile per hour (1.6 km/h) loaded, or 2 miles per hour (3.2 km/h) unloaded. The average trip time from the VAB along the Crawlerway to Launch Complex 39 is about five hours. Each crawlerway is 7 ft (2 m) deep and covered with Alabama and Tennessee river rock for its low friction properties to reduce the possibility of sparks. In 2000, NASA unearthed and restored an Apollo-era segment of the crawlerway to provide access to a high-bay building in order to provide protection from a hurricane.

Kennedy Space Center has been using the same two crawlers, nicknamed "Hans" and "Franz," since their initial delivery in 1965. In their lifetime, they have traveled more than 3,400 miles (5,500 km), about the same driving distance as Miami to Seattle.