Ever since Konstantin Tsiolkovsky, an eminent Russian rocket scientist, first put forward the idea of a "space elevator," in 1895, enthusiasts have dreamed of traveling to space using not much more than a long piece of cable and a boxcar. But until recently, few, if any, companies had actually proposed building one.
That is, until a large Japanese construction company, called Obayashi, stepped forward last month. Obayashi announced that it wanted to send a cable 60,000 miles into space, and suspend it there with a counterweight. Passengers would travel to a terminal station at 22,000 miles (see diagram) propelled at 200 kilometers an hour, possibly using a maglev-type magnetic railway. And the trips would last about a week. Obayashi said it hoped to complete the project by 2050.
Now, if you think all that sounds a bit far-fetched, you’re not alone. That’s what self-identfying members of the "space elevator community" think too.
"I think it’s great marketing on their part. They received a ton of publicity because of it, but do I see Obayashi building an elevator by 2050? No," said Marc Boucher, editor of SpaceRef, and Spaceelevator.com. "If someone is going to build an elevator, it’s going to be part of a consortium. It’s not a mega-project, but a super-mega-project, like the International Space Station."
Michael Laine, CEO of space elevator developer LiftPort, notes that several large companies, including Google, Otis, and Lockheed Martin, have made announcements about space elevators in the last decade, each generating "a fair amount of viral buzz." But to "the best of my knowledge, none of these organizations have ever contacted anyone in the elevator community that I know. And after more than a decade, I know just about every serious researcher in the field."
Still, enthusiasts are adamant an elevator is feasible in the long run, given more research, a breakthrough in nanotubes (which, because of their super-strength, would be used for the cable), cooperation both internationally and between public and private sectors, and, of course, bundles (and bundles) of cash.
The community meets every year for a conference held at Microsoft’s campus in Redmond. It publishes papers, organizes itself into groups, such as the International Space Elevator Consortium, and holds competitions, like the Space Elevator Games.
The 2010 contest, the last held, involved two challenges: building a string strong enough to reach from the ground into the air, and finding a means of propelling the car. NASA set aside $2 million for the first challenge, seeing if any team could provide nanotubes that might be used for the job. But, as yet, it is has not awarded the money.
Laine says an elevator tether would need to withstand at least 80 to 90 gigapascals (steel has the strength of about 3 gigapascals) of pressure. But the current strongest piece of nano-tubing goes only to 63 gigapascals. And, the longest-known string is still many, many miles short of what would be needed.
However, a team did win in the second category, the Power Beaming Challenge, sending a robot 3,000 feet up a tether using a remote laser beam. And, the company behind that feat, Seattle-based LaserMotive, is now developing its technology.
LiftPort, which started life as a NASA project in the early 2000s before undergoing a several-year "hibernation," is taking a roundabout route to the holy grail. Laine says while nanotubes are not available in sufficient strength, or length, it makes sense to concentrate on what is feasible now.
Hence, it is working towards a lunar space elevator, which would be tethered to the moon using a material such as Kevlar (about 6 gigapascals). Such a system, Laine says, would make moon-landings easier, could be launched using the rockets that take satellites into lower orbit, and could be completed by 2020.
"We’ll build the lunar elevator first, then come back to the earth elevator, once the materials are available for us," he says. Elevator, going up!