Saturday, September 26, 2009

Japan hopes to turn sci-fi into reality with elevator to the stars

An artist's impression of the platform
An artist's impression of the platform of the proposed space elevator,
which would climb 22,000 miles into space

Leo Lewis in Tokyo

From cyborg housemaids and waterpowered cars to dog translators and rocket boots, Japanese boffins have racked up plenty of near-misses in the quest to turn science fiction into reality.
Now the finest scientific minds of Japan are devoting themselves to cracking the greatest sci-fi vision of all: the space elevator. Man has so far conquered space by painfully and inefficiently blasting himself out of the atmosphere but the 21st century should bring a more leisurely ride to the final frontier.
For chemists, physicists, material scientists, astronauts and dreamers across the globe, the space elevator represents the most tantalising of concepts: cables stronger and lighter than any fibre yet woven, tethered to the ground and disappearing beyond the atmosphere to a satellite docking station in geosynchronous orbit above Earth.
Up and down the 22,000 mile-long (36,000km) cables — or flat ribbons — will run the elevator carriages, themselves requiring huge breakthroughs in engineering to which the biggest Japanese companies and universities have turned their collective attention.
In the carriages, the scientists behind the idea told The Times, could be any number of cargoes. A space elevator could carry people, huge solar-powered generators or even casks of radioactive waste. The point is that breaking free of Earth's gravity will no longer require so much energy — perhaps 100 times less than launching the space shuttle.
“Just like travelling abroad, anyone will be able to ride the elevator into space,” Shuichi Ono, chairman of the Japan Space Elevator Association, said.
The vision has inspired scientists around the world and government organisations including Nasa. Several competing space elevator projects are gathering pace as various groups vie to build practical carriages, tethers and the hundreds of other parts required to carry out the plan. There are prizes offered by space elevator-related scientific organisations for breakthroughs and competitions for the best and fastest design of carriage.
First envisioned by the celebrated master of science fiction, Arthur C. Clarke, in his 1979 work The Fountains of Paradise, the concept has all the best qualities of great science fiction: it is bold, it is a leap of imagination and it would change life as we know it.
Unlike the warp drives in Star Trek, or H.G. Wells's The Time Machine, the idea of the space elevator does not mess with the laws of science; it just presents a series of very, very complex engineering problems.
Japan is increasingly confident that its sprawling academic and industrial base can solve those issues, and has even put the astonishingly low price tag of a trillion yen (£5 billion) on building the elevator. Japan is renowned as a global leader in the precision engineering and high-quality material production without which the idea could never be possible.


Space Elevator Most of a rocket’s fuel is spent blasting through Earth’s thick atmosphere and out of the planetâ€s strong gravitational field. But here’s an alternate strategy for getting payloads up to space: Construct a 62,000-mile-long cable jutting straight out from the equator, hold it in place with centripetal force, then lift satellites and spacecraft out of the atmosphere with a giant freight elevator. One major hang-up: Cable strong enough to support the system does not yet exist, though it could be made from carbon nanotubes. Shown above is “The Climber” which sill carry the payload. John Macneill

The biggest obstacle lies in the cables. To extend the elevator to a stationary satellite from the Earth's surface would require twice that length of cable to reach a counterweight, ensuring that the cable maintains its tension.
The cable must be exceptionally light, staggeringly strong and able to withstand all projectiles thrown at it inside and outside the atmosphere. The answer, according to the groups working on designs, will lie in carbon nanotubes - microscopic particles that can be formed into fibres and whose mass production is now a focus of Japan's big textile companies.
According to Yoshio Aoki, a professor of precision machinery engineering at Nihon University and a director of the Japan Space Elevator Association, the cable would need to be about four times stronger than what is currently the strongest carbon nanotube fibre, or about 180 times stronger than steel. Pioneering work on carbon nanotubes in Cambridge has produced a strength improvement of about 100 times over the last five years.
Equally, there is the issue of powering the carriages as they climb into space. “We are thinking of using the technology employed in our bullet trains,” Professor Aoki said. “Carbon nanotubes are good conductors of electricity, so we are thinking of having a second cable to provide power all along the route.”
Japan is hosting an international conference in November to draw up a timetable for the machine.



Stranger than fiction
“Riding silently into the sky, soon she was 100km high, higher even than the old pioneering rocket planes, the X15s, used to reach. The sky was already all but black above her, with a twinkling of stars right at the zenith, the point to which the ribbon, gold-bright in the sunlight, pointed like an arrow. Looking up that way she could see no sign of structures further up the ribbon, no sign of the counterweight. Nothing but the shining beads of more spiders clambering up this thread to the sky. She suspected she still had not grasped the scale of the elevator, not remotely.”
From Firstborn by Arthur C. Clarke and Stephen Baxter
Publisher: Del Ray
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