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Space elevators stuck on the first floor

作者:梁丘钐    发布时间:2019-02-28 01:05:01    

By Maggie McKee A NASA competition designed to lay the groundwork for futuristic space elevators has ended with no one scooping the two $50,000 top prizes. But officials say the contest is just the first step in developing the technologies needed to use robots to lift objects into space on long, thin super-strong tethers. Ten teams competed in the challenge, which was held over the weekend at NASA’s Ames Research Center in Mountain View, California, US. The event was split into two competitions to test either robot climbing or tether strength. Seven teams entered the “Beam Power Challenge”, where participants built robots that scaled as far as possible up a 61-metre cable. They used photovoltaic cells to convert radiation from an industrial searchlight into electricity for the climb. Those that carried the most weight the highest – while maintaining an average speed of 1 metre per second – would have won a $50,000 grand prize. But no team was able to meet the speed requirement, although a group from the University of Saskatchewan in Canada set the height record at 12 metres. Sustaining power for the climb appears to have been the main limiting factor. “One of the problems with a power beam is you get so much fall off in light intensity the farther it goes,” says NASA spokesman, J D Harrington. He adds that teams were restricted to using NASA’s searchlight as the power source this year, but says they will be able to design their own in 2006. “They can use lasers, microwaves, whatever they like,” he says. Four teams entered the “Tether Challenge”, which also carried a $50,000 purse. In that contest, teams had to build tether loops lighter than 2 grams. These had not only to be stronger than their competitors’ tethers, but also 50% stronger than a reference tether supplied by NASA, made from commercially available materials. A tether built by Centaurus Aerospace of Salt Lake City, Utah, managed to carry 544 kilograms before snapping. But that was still not as sturdy as the house tether, which supported 590 kg. The house tether was produced by the Spaceward Foundation, a space advocacy group in Mountain View that administered the contest with NASA. NASA says it was pleased with the quality of the entries, especially considering the event was only announced in March. “We would have probably been more surprised had someone won – they only had six months to prepare,” says Harrington. Next year, both contests will be repeated but the top prizes will each rise to $200,

 

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