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When Nasa’s giant SLS rocket carries out its first mission, it will be brought to the launchpad by one of the largest vehicles ever built. And driving it requires massive concentration.
Within the next two years, Nasa plans to blast the first of its Space Launch System (SLS) rockets on a 384,400 km (238,855 mile) uncrewed voyage around the Moon. With plans for lunar space stations, Moon bases and Mars missions, the future of America’s state-funded astronaut programme depends on its success.
Although the SLS is brand new, the multi-billion-dollar 98m-tall (322 ft) launcher will begin its journey at the Kennedy Space Center in Florida on a vehicle that is more than 50 years old. And, for the team charged with conveying the rocket the seven kilometres (4.3 miles) to the launchpad, the pressure is on.
The four-tracked crawlers were built in 1965 to carry the Saturn 5 rocket that took astronauts to the Moon. They were adapted in the 70s for the Space Shuttle. Now, one of these has been refurbished and strengthened to convey the SLS. Despite some modernisation, the fundamental design of the 40-metre-long (131 feet), 35 metre-wide (114 feet), 2,700 tonne (six million pound) giant tracked vehicle remains the same.
“We brag sometimes that the crawlers were made with a slide rule and not a computer,” says Myers, who has been driving the crawler-transporters for more than 35 years. “They were built better – overbuilt – than many vehicles today and as a result they’re very reliable.”
That a machine so vast can move at less than a mile an hour (1.6km/h) is one of the greatest achievements of the original engineers. “It’s not about how fast it can go – it’s about how slow it can go,” says Myers. “It has the capability for positioning and docking its platform on the launch pad to within half an inch and on command it can move an eighth of an inch.”
With 50 years and some 3,000 km (2,000 miles) on the clock, Nasa expects the crawlers to be in operation for at least another three decades. With the latest refurbishment complete, testing is well underway for the first SLS mission. And, just to be certain they’ve got their calculations right, before the strengthened crawler is used to carry the new rocket, it will be tried out with an equivalent weight in concrete beams.