Thoughts on the Space Elevator

Keith Curtis writes to tell us that Glenn Reynolds, of Instapundit fame, has posted his thoughts on why NASA should be building a space elevator instead or their current plans. Keith has also posted his throughts from an engineer's perspective (although admittadly still not a rocket scientist). "The challenges are many, but it has been a viable option since carbon nanotubes, structures so strong that one the width of a human hair could lift a car, were invented. A space elevator could be between 10 and 2000 times cheaper than conventional technology and will force NASA to change just about everything they do. Hopefully one day that bureaucracy will wake up and realize it."

Comments

Pixiedust

[prurientknave]

If magic pixie dust were invented it would be such a waste to spend all this money on conventional boosters. Come on NASA! Drop what's known to work and concentrate on the pixie dust formula.

Re:Pixiedust

[An Onerous Coward]

I once read an interesting article on cluster computing, which basically said that the fastest and cheapest way to solve any truly big computational problem was, "Wait a few years before buying the cluster." Given the rates at which prices for storage, processing, and networking were plummeting, a problem that would take eight years to solve today could be solvable in four years two years out, and in two years two years from now. So by putting it off for two years, you'd shave two years off the project.

The current plan doesn't get us to the moon until 2018 anyways, and without a cheap way to keep things flowing between here and the moon, the chance of a sustained human presence is nil. So we could spend $100B building basically the same propulsion-based solutions we've always been building, or we could spend a much smaller sum on fundamental materials research.

I don't see it as a gamble, because without a drastically cheaper way to get into space, we'll just retrace the journeys of the Apollo missions. Then the whole nation will kick back, pop open a beer, mutter "Yep, still got it," and wait to do it all over again in 2050.

Count me in with the pixie dusters.

Re:Pixiedust

[Asterixian]

Given the rates at which prices for storage, processing, and networking were plummeting, a problem that would take eight years to solve today could be solvable in four years two years out, and in two years two years from now. So by putting it off for two years, you'd shave two years off the project.

This may be true in the everyday world of cut-throat competition, but if we call this "optimal" and everybody does it, everybody waits two years, and nobody puts forth the effort to realize the gain in productivity. Leeching off of technology that hasn't been invented yet reaps the benefits of work paid for by whomever goes first. I call it a technologically-oriented game of chicken.

Looking more closely at NASA's past projects, you will find that NASA takes precisely that role - the government puts up huge sums of money on an unproven technology, and the world reaps the benefits years (or decades) later. From the taxpayer's perspective, the only important criterion is whether the indirect reward will pay back the taxpayer for the up-front costs.

It may be more cost effective technically..

[thedak]

But, I don't remember ever hearing that we actually have the technology to produce enough carbon nanotube material to actually build a prototype device of some sort let alone a cable spanning to LEO. I realize it's 14 years away.. but there's no guarentee we will actually have the capacity by that time. As far as I'm concerned we're better off building what can actually be finished come 2020 let alone tested and on our way to the moon.. again..

I dont get it...

[imsabbel]

Maybe i am a bit out of touch (although i doubt it, being physicist and seeing people who actively work in the nanoparticle research and astrophysics department everyday), but i think this is all such a bullshit.

Space elevator this, space elevator that. Its just a pie-in-the-sky dream, and will be for the next century(ies). We dont have bucktubes "thick as a hair but strong enough to lift a car".
We dont even have them a meter long and strong enough to lift an apple.
And even than, it took millenia to get from iron->steel->a few km steel wire for bridges/ect.
Singularity this or that, you shouldnt expect something like the support of the golden gate bridge via nanotube based cables the next decade(s)
(not even mentioning the hurdles of a structure 30.000km+ long and sturdy enough to support the lifting vehicle and atmospheric conditions).

Also, the best we ever did concerning long wires and space was a test a few years ago, where they even failed to unwind a 300km, unstained wire in free space.

Not to mention that to get the whole framework running you need an efficent way of getting material and people up there to begin with... without a shuttle mk2 or 3 or 4 or 5 there is not even a point to start the whole shit.

But it seems nowaydays you only need to throw some buzzwords like "nanotubes" into the crowed and they would believe you even if you promised them portable teleporters...

Re:I dont get it...

[deathcloset]

you're a physicist?

how could you use an analogy like "it took millenia to get from iron->steel->a few dm steel wire for bridges" when it took millenia to get from horse and carriage to the car...but then only a half-century to get into space?

seriously, what's the average velocity of a horse and carriage vs. the average speed of an orbiting body?

now juxtapose that over that timeline...

and what about energy? we had fire to heat us for millenia. then within decades of the light-bulb we have nuclear reactors.

please formulate a similar chart to the aforementioned.

your the kind of physicist who looks through microscopes not telescopes, aren't you?

So, lift a car first.

[Tackhead]

> The challenges are many, but it has been a viable option since carbon nanotubes, structures so strong that one the width of a human hair could lift a car, were invented.

No, it hasn't.

The space elevator will become viable when someone creates a strand of carbon nanotube and lifts a car with it.

If you want to make me believe that a carbon nanotube space elevator is a viable proposition, demostrate that you can build a carbon nanotube suspension bridge first.

Doesn't have to be a replacement for the Brooklyn Bridge or the Golden Gate. A footpath over a creek at your local engineering college will do.

Until then, you're as likely to go into orbit on a space elevator's as you are on a matter/antimatter drive: as in "not at all".

difference between the two:

[GroeFaZ]

Launch Loop presentation and Space Elevator presentation .

For large projects to be realized, they either have to be of decisive strategic/military value during war (Manhattan project), or they have to completely capture the hearts of the citizens that are supposed to pay for it all (Apollo Project, "before this decade is out..."). Clearly, for the Space Elevator, the latter is the case. I, for one, have not heard of Launch Loop before, and the dry PDFs and text files that are Google's #1 on the term didn't really invite me to care about it. The Space Elevator, on the other hand, has been part of the popular culture for decades, and has recently surged astronomically (no pun intended) in terms of mainstream recognition.

Just as it would have been more affordable and scientifically more valuable to gradually conquer space and ultimately the moon (i.e. with manned space stations and a launch from space etc.), it was the extreme appeal of the "moon shot", the giant leap that won the favor over the more economical approach.

KE = 0.5 * m * v^2

[klossner]

Structural engineering issues aside, the big problem with space elevators is the junk in low earth orbit. If a 200 kg object hits the structure at a relative velocity of 15,000 MPH, it will release energy equivalent to one ton of TNT.

from the lab to working product...

[alizard]

Show me an actual, working 100 meter long CNT cable with strengths comparable to what the Space Elevator will require and I'm ready to discuss it.

If you simply want to get cheap payload into orbit this decade using materials that are NOT theoretical, find a way to get funding to the blimp-to-orbit people at JP Aerospace.

Lots of things wrong with the Space Elevator concept... it breaking could kill a lot of people... but the dealkiller is that you can't build a structure with theoretical materials, and it shouldn't take a "rocket scientist" to figure this out.

Re:Launch Loop

[Catbeller]

The US may have trouble building maglev trains, but the rest of the world hasn't.

Sadly, the US isn't building much of anything anymore. We're a nation of managers and businessmen, not engineers.

Because most of the US lacks the basic knowledge set to even understand how a space elevator will work, or the trained imagination to envision what to do with it, the subject is incomprehensible to our citizenry.

We don't even build REGULAR trains anymore. We've deemed them dinosaurs used by the poor or the shipping industry looking to capitalize on a dying infrastructure, and left the rails to rot in a free-market grave. Maglev? Americans want a faster Mustang. They care nothing for trains, and never heard of maglevs in other countries. We think MONORAILS are stupid, even tho they are far superior for public transit than the 19th century horrors in Boston, New York, or Chicago.

I don't see America ever considering building a beanstalk.

Here's what I'm hearing and reading about the NASA back-to-the-moon program, as a for-instance: We went there before, over thirty years ago. Why go again?

This is not a field of dreams for building a fantastic SF future. Look to Japan, to China, even to Europe, maybe, for the human future in space. Far-sighted Americans will flock to those projects. But they will not be built in the US. We're lost in a dream in which the 1950's never ended, oil is cheap, we're the biggest dog on the block, and cars are the main means of self expression.

Re:"Unobtainium"

[wurp]

Hmm, well, I have a BS in Physics and Mathematics, double major, so I'm not just assuming "there must be an answer, and someone smarter than me will know it". If you were as smart as you seem to think, you would realize that looking in on a problem from an essentially layman point of view (which both you and I have) doesn't give you the vantage point to argue what complex engineering processes can't do. Please note that your argument about bond strength is a red herring - I never asserted we would figure out a way to make the individual bonds stronger.

Basically what we have is a difference of attitude. I see "we have the engineering figured out for using 65 GPa ribbons for a space elevator, and we can produce material now that could almost theoretically have that strength, and in theory we could produce materials almost twice as strong" and I think, this is something that needs research. I am not claiming that 10 years and $100 billion will build a space elevator - I'm claiming that it could put us in a position to know how to build a space elevator, so getting the real funding becomes politically feasible.

You see the same statements, and throw up your hands saying we can't do it. Your arguments that we can't do it are pretty damn weak...

• you don't even seem to be arguing that we can't do it, just that it would be expensive, once we find, say, 30% tougher nanotubes and ways to composite them into ribbons 70% as strong as the tubes are individually
• you assume that we can never do better than our current models of the chemistry and engineering demonstrate. Remember the 9.6kbaud "physical limits" on modems?
• your position seems to be that we've achieved almost all we will achieve with a technology that we didn't even know existed 15 years ago

So your position is that we could almost do it with the materials we have now, on a 15 year old technology, if we had the right compositing process, but that it's ludicrous to think that we could actually do it with 10 more years of research focused on improving strength of individual tubes and processes for producing ribbons?

Comparing this to alchemists' dreams of lead to gold is beyond laughable. Assuming that you know more than the researchers dedicating themselves to this research is ridiculous. Assuming science and engineering will go backward rather than forward is demonstrably false. Asserting a strawman argument about bond strength is a red herring. And repeated commands to "deal" (by which you mean adopt your pessimist philosophy) are obnoxious.