Obayashi To Build Space Elevator By 2050

mattr writes "Japan's Obayashi Corp. has announced plans to build a space elevator by 2050. They are famous for wrecking skylines with the over-sized bullet train station in Kyoto, the world's tallest self-supporting tower Tokyo Sky Tree and just recently, the beginnings of the Taipei Dome. It will take a week at 200 kph for your party of 30 to reach the 36,000-km-high terminal station, while the counterweight [swings along at] 96 km high, a quarter of the way to the Moon."

Comments

Re:Is that so?

[mikael_j]

Well, here's a list of some of their previous projects.

Re:English?

[ChatHuant]

WTF does that last sentence even mean?

It's just the editors being up to their usual standards of quality. The elevator cable doesn't end at the geostationary station (at 36000 km); it continues beyond it for another 60000 km, and terminates in a counterweight. This counterweight is supposed to be positioned 96 THOUSAND kilometers from the surface, hence the mention of the quarter of the distance to the moon.

Materials science 101

[Kupfernigk]

There has already been a paper suggesting that SWCN may not be up to the task due to "dislocations".

No quotation marks needed. The problems in designing very strong materials have been known since WW2. The challenge can be expressed very simply: the more the strength depends on having a complete covalent structure (in CNTs the bonds have some ionic characteristic owing to the p-hybridisation but the same logic applies) , the greater the weakening effect of even a single fault. If a cosmic ray unzips a few bonds, the stresses will concentrate on the bonds on either side, and the split is likely to propagate. In strong metals we fix this with alloying components, very crudely like the gravel in concrete, which stop those dislocations from extending right through the material, but equally adding alloy components reduces the ultimately obtainable strength from a perfect structure. It is a tradeoff, as usual.

Re:Counterpoint

[CrimsonAvenger]

Actually no. A space elevator is a bit like a train track with only 2 stations at each end. If you want to go anywhere else, it is more or less useless. For example its almost totally useless for LEO. Well tbh it is totally useless for LEO.

Umm, no.

Below the terminus at GEO, the elevator is moving at less than orbital speed. Above the terminus (all the way to the counterweight), it is moving at more than orbital speed.

This can be taken advantage of to deploy things to positions in LEO (release something at just the right altitude along the space elevator, it'll drop down to a perigee at the altitude you want it, then a small boost from a conventional rocket, and you're in a circular orbit in LEO. At much lower cost than a rocket from the ground.

Likewise, it can be used to toss things into the outer system - the counterweight is moving at far above escape speed (~7000 m/s at 96000 km), so you can just let something go there, and it'll be heading off in the general direction of Jupiter. It won't go as high as Saturn's orbit without a higher counterweight, of course, but lower aphelions are possible by releasing at a lower altitude than the counterweight...