Friday, October 20, 2006

Race to space in New Mexico - Nature

Published online: 19 October 2006; | doi:10.1038/news061016-14

Space elevator games kick off on Friday.

Katharine Sanderson

Up for grabs: there's $2.5 million at stake in these games.

An airfield in New Mexico will this weekend host a celebration of space technology: the second annual X Prize Cup games.

The festival is a huge space PR exercise and a showcase for private companies working on space technology. But the main draws are three events that will see space enthusiasts competing for a share of $2.5 million in prize money: the Lunar Lander Challenge, the Vertical Rocket Challenge and the Space Elevator Games.

The lunar lander and vertical rocket competitions are sponsored by NASA, and feed into their ambitions to travel to the Moon. Both contests involve demonstrating an unmanned vehicle that can take off, climb vertically for 50 metres, stay airborne for either 90 (the lander) or 180 (the rocket) seconds, and then land 100 metres from the take-off point.

Experts say the difference in gravity and air pressure between here and the Moon doesn't make too much difference to the design of a lander, and so the games are a good place to test such technology.

Reach for the stars

But the real excitement surrounds the Space Elevator Games, which is split into two $200,000 prizes.

One competition involves making a strong cable of lightweight nanotubes, which is what would be needed to build a real elevator into space. Teams must enter a 2-metre loop of carbon nanotubes no wider than 200 millimetres and no heavier than 2 grams, which will be tested in a tug-of-war. To win, a competitor must have the strongest loop and beat the industry standard of 5.8 Gigapascals by at least 50%.

The real crowd-pleaser is the second half of the elevator games: the climber competition. Entrants must climb a 50-metre ribbon, called the tether, powered only by power beamed from the ground, to cut down on the weight of any fuel or track system.

Last year no team managed to climb the tether. Yet this year, the rules are even tougher. To win climbers must make it to the top carrying a certain amount of weight in 50 seconds or less, and come back down again. "It remains to be seen if anyone can meet all those requirements," says Ted Semon, who is reporting on the games for the official space elevator blog. "I give it at least a 50-50 chance that someone will," he told

By the end of Wednesday, four out of 12 teams had got through pre-race qualification. Semon says there's no danger of rival teams stealing each other's ideas. "It's much too late to change anything fundamental," he says. "Each team knows what the others are doing by now. Some teams are even sharing equipment."

Just a game?

But isn't a small device shimmying up a 50-metre ribbon very different from the massive reality of a genuine space elevator?

"The climber challenges are set up to directly crack what really needs to be done," says Brad Edwards, who sits on the board of the Spaceward Foundation, which is overseeing the games. In a few years, he predicts, the tether will be attached to a balloon three kilometres up. This will eventually lead to the real thing, he says — a tether stretching to an anchor in orbit.

Mass space travel is a question not of technology, but money, Edward says. Private finance will drive space exploration, he says, and the space elevator is a cheap way for people to buy in.

The material for the tether remains a contentious issue, and there are debates about whether nanotubes can be made strong and light enough to work. Still, says Edwards, there will always be demand for these strong materials, even though space elevators would be a niche part of the market. "It would be driven by tennis rackets and golf clubs."


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