Why Japan Probably Won't Have a Space Elevator by 2050

Japanese construction company Obayashi wants to build an elevator to space — and they want to use carbon nanotubes to get there. The Tokyo-based company plans to use 60,000-miles of the cylindrical carbon structures, anchored to Earth's surface, to shuttle an elevator to and from a distance about a tenth of the Moon's distance from the Earth.

Here's why that probably won't happen.

Based solely on the company's meager description — published two days ago in the Daily Yomiuri — it sounds as though Obayashi is flirting with the idea of using the carbon nanotubes in a "ribbon" setup — a popular concept among those familiar with space elevators. The basic idea is to use strong, light, and almost inconceivably flat sheets of carbon nanotube ribbon (think several meters wide, and thin enough to make paper seem bulky) as a rail system that runs perpendicular to Earth and keeps hold of robotic cars that glide along the ribbon to and from the planet.

If it sounds a little fanciful, that's because it is... at least, for now. Getting carbon nanotubes into this ribbon configuration is a significant technical hurdle. Translation: we can't do it yet, and it's possible that we never will; for the last five years, NASA has offered $2 million dollars to anyone who can can come up with a carbon nanotube tether strong enough to bring us significantly closer to making space elevators a reality. The prize money has gone unclaimed. That's not saying it never will, but the challenge may call for a brand new material altogether — maybe even one we haven't discovered yet.

There also appears to be some confusion over how exactly Obayashi plans on anchoring this thing to Earth. The Daily Yomiuri is reporting that the company wants to secure the elevator to the ground, but most space elevator aficionados believe the best place to secure a space elevator is at the bottom of the Pacific. (There's also a possibility that this was just misreported by the Daily Yomiuri; CNET has said that Obayashi does, in fact, plan to anchor the elevator on the ocean floor.)

In any case, this all feels very slipshod and poorly put together, both on the part of Obayashi and the outlets reporting on their goals. Given their intentions to erect a space elevator out of unproven materials in what may be an unfeasible location, we'd say it's more than fair to take this news with a couple plentiful scoops of salt.

Want to know more about space elevators? Check out our backgrounder, or our coverage from last year's Space Elevator Conference.

[The Daily Yomiuri | CNET]
Top image by Michael Evans