Space Elevator Conference Prompts Lofty Questions

itwbennett writes "Even the most ardent enthusiasts gathered at the annual Space Elevator Conference on Friday don't expect it to be built anytime soon, but that doesn't stop them from dreaming, planning, and trying to solve some of the more vexing problems. One of the trickiest questions is who's going to pay for the operational costs when an elevator is eventually built. 'It's been nine years we've been looking for someone' to study that, said Bryan Laubscher, one of the leading space elevator enthusiasts and principle at Odysseus Technologies, a company working on high-strength materials."

Comments

Re:Elevator to nowhere

[wmbetts]

Fine then! When it's built you can't ride it!

The major issues and such

[JoshuaZ]

Anyone interested in this issue should read the NIAC report http://www.spaceelevator.com/docs/521Edwards.pdf which discusses the issues in detail and the technical problems. Space elevators would make space travel much cheaper. But the technical issues are immense. The NIAC report carefully outlines the major issues and how they might be handled. We would need to make extremely high quality carbon nanotubes at an immense scale. We also would need to put into space a structure orders of magnitude larger than anything we've put in space. Indeed, a space elevator would be one of the largest physical structures ever made by humans. And the engineering hurdles, such as the problems of wind in the lower atmosphere, are massive. But there's nothing about the idea that is physically impossible. The primary issues are issues of scale. And the issues are being worked on. Right now, there's a lot of work on making carbon nanotubes of high quality in a large scale. Since such nanotubes would have many different applications there's a lot of funding for that and that will likely be extremely beneficial to humanity well before it scales up to anything near that needed for a space elevator. Since the nanotube manufacturing is the primary technical hurdle, this is a good thing. I doubt we will see a space elevator in my lifetime, but maybe my children, or their children, will see it. And on that thing ribbon, space travel will finally become as cheap as so many have envisioned it.

Re:$18B

[Anonymous Coward]

That number is way lowballed. What, are they thinking the price of the nanotube cable is comparable to the market price of carbon?

Anyone dumb enough to pay to build a space elevator this early in the game will lose their money.

Seriously, it's an elevator from the ground to one point in geosynchronous orbit. A payload released at almost any other altitude will need reaction mass to establish a stable orbit, most of which will be expended in the direction of the cable and thus wear it down. (The exceptions are payloads released near geosynchronous orbit which will establish elliptical or parabolic orbits.) Finally, other satellites and debris at lower orbits especially, will impact the cable, both damaging it and setting up waves which will need to be safely dissipated somehow. A paint chip at 500 miles up is going to hit at around 17k miles/hr. and will have plenty of kinetic energy that needs to go somewhere.

Commercially, this is useless, even if you could build it easily and cheaply. It's an engineering nightmare, and no amount of focus on the easy parts of the design -- and the material is the easy part -- will change that.

Re:Elevator to nowhere

[Baloroth]

Do you know anything about space elevators? Seriously. They're a great idea. Practically speaking, they are also very difficult, but if we could build one, the cost of traveling to orbit would become relatively speaking extremely cheap (technically, the energy requirements would stay the same. But the delta-v required would become as low as we please, making very cheap and low-power sources effective). Long term, unless we find a much better way to get to space, they are very likely to be built.

I agree that that is a very stupid question. Obviously, whoever uses it would pay for its use. Aka, commercial companies, NASA, military, etc. Since lots of people want to put stuff into space, lots of people could fund its operation .Probably it would be run by a company or government who would charge for its use (preferably, there would be at least two to introduce competition). That part is relatively easy. Its construction, on the other hand, is quite a problem. Financially and technically. However, it is a very good idea. Keep in mind, 150 years ago space travel on rockets was also just an idea in a few peoples minds. Turns out it isn't such a bad idea after all.

Plus, having an actual stairway to heaven would be pretty awesome...

Please Mod Parent Up

[Anonymous Coward]

Launch Loops are indeed far more interesting and practical. Can anyone here explain why space elevators seem to be the more popular idea among the two?

Re:Please Mod Parent Up

[Rei]

A couple hundred miles of maglev track versus tens of thousands of miles of unobtanium cable exposed to micrometeorites, space debris, undamped oscillations, etc. Hmm, which is more realistic...

And I have no clue what you mean by "80 mile high bridge", except to assume that you've grossly understood how a Lofstrom loop works.

The key issues are:

1) A Lofstrom loop requires no unobtanium. It may well be *physically impossible* to create the material needed for a space elevator on Earth, let alone economically practical. After all, the strongest *invididual SWNTs* measured thusfar were barely over 60GPa at the density of graphite, when you need a *bulk cable* that's ideally over 100GPa at graphite densities, preferably over 120.

2) A Lofstrom loop transmits power (the primary lift cost from both systems) at about 50% efficiency. A space elevator beams power at a couple percent efficiency. Hence a Lofstrom loop costs an order of magnitude less to operate.

So we're back to the start. Why a space elevator, apart from the fact that everyone knows of it through sci-fi? Wait, I think I answered my own question.

Re:Please Mod Parent Up

[mosb1000]

A space elevator is essentially a static structure, it does not require any power to stay in place. As such, it is more like a building than a machine. It's much less complex, which means quality control would be much simpler/possible. There are many questions about how you would build a launch loop too. The only real question about a space elevator is the material. They think single walled carbon nanotubes could be strong enough to do the trick. That means the technology is more likely to pan out in the long run. And if you could build it, it could be much cheaper to operate and much simpler to build than a launch loop.

So, in short, the space elevator gets more attention because it is a more compelling proposition, and seems more likely to succeed.

Re:Please Mod Parent Up

[Darfeld]

What about the fact that Space elevator allow easy atmospheric re-entry and the launch loop does not?

Substantial Progress being made

[mbone]

One of the interesting things about this conference (which I attended) is that nanoscience researchers on Friday reported substantial improvements in the ability to make carbon nanotubes. They can now "grow" 1 cm nanotube mats, which can be spun into fibers. This is a substantial improvement from even 1 year ago.

I still think that a terrestrial space elevator is a decade out, but this year has convinced me that it is coming much faster than a lot of people think.

Re:Anytime soon

[hedwards]

Projects like this are frequently as interesting, if not more so, for the byproducts that have to be developed in order to make it work.

Re:panax

[PwnzerDragoon]

Shit, we lost another one. I keep telling them to be more careful where they drop those ropes.

Re:Elevator to nowhere

[dvice_null]

"The aeroplane will never fly."

— Lord Haldane, Minister of War, Britain, 1907 (yes, 1907).

"No flying machine will ever fly from New York to Paris ... [because] no known motor can run at the requisite speed for four days without stopping."

— Orville Wright, c. 1908.

"The whole procedure [of shooting rockets into space] . . . presents difficulties of so fundamental a nature, that we are forced to dismiss the notion as essentially impracticable"

— Sir Richard van der Riet Wooley, British astronomer, reviewing P.E. Cleator's 'Rockets Through Space,' in Nature, 14 March 1936

Re:Or build a skyhook

[physicsphairy]

Well, one idea is that you catch random orbiting junk at the other end, replenishing the lost momentum. In any case, efficiency isn't particularly important. The major limitation on getting things into space right now is construction, launch logistics, etc. If we could somehow be continuously sending things into space, it would be well-worth having to send two or three times the fuel along with.