NASA's colossal crawlers mark half a century of service

Two veterans of the US space program have marked 50 years of service with in appropriately sedate style. In 1965, a pair of gigantic crawlers were built to move the Saturn V moon rockets to the launch pad. Half a century later, they are still in service and being upgraded to handle NASA's Space Launch System (SLS) and other launch vehicles. To celebrate, the 6 million lb (2.7 million kg) Crawler-Transporter 2 (CT-2) made a rollout for a visitor and media day at less than one mph...