September 22, 2008
Japan Looking To Build World’s First Space Elevator
Japanese scientists are devoting themselves to cracking the greatest sci-fi vision of all: the space elevator.
The space elevator is one of the most tantalizing concepts: cables stronger and lighter than any fiber yet woven, tethered to the ground and disappearing beyond the atmosphere to a satellite docking station in geosynchronous orbit above Earth.
The 22,000 mile-long 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.
The scientists say the space elevator could carry any number of cargoes, including 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 traveling abroad, anyone will be able to ride the elevator into space," said Shuichi Ono, chairman of the Japan Space Elevator Association.
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 organizations for breakthroughs and competitions for the best and fastest design of carriage.
The idea of the space elevator does not mess with the laws of science but presents a series of very complex engineering problems.
Japan is believes 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.
But the cables will be the biggest obstacle. 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.
Such a cable would have to be exceptionally light, extremely strong and able to withstand all projectiles thrown at it inside and outside the atmosphere.
According to the groups working on designs, the answer lies in carbon nanotubes - microscopic particles that can be formed into fibers and whose mass production is now a focus of Japan's big textile companies.
The cable would need to be about four times stronger than what is currently the strongest carbon nanotube fiber, 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, according to Yoshio Aoki, a professor of precision machinery engineering at Nihon University and a director of the Japan Space Elevator Association.
There also remains 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."
In November, Japan will host an international conference to draw up a timetable for the machine.