Talk:Space elevator/Archive 2

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cost comparison

I am not the one who is comparing rocket costs to elevator costs. . But you're not getting what the numbers are. The rocket launch cost is not repaying capital costs. It just isn't. These are per-launch costs. So, that means that reusable rockets are repaying their maintinence and refueling, while disposable rockets are paying for their construction. A reusable elevator is paying only for its power. If the rocket numbers are not repaying initial costs, then the elevator costs shouldn't either. They are cost per launch. So is the elevator. End of story.

That does not follow. The 25000 is all inclusive. The 1.74 is marginal idealised (not theoretical minimum but idealised - there is a difference - but this is not the main point here). It is THAT COMPARISON WHICH IS WRONG. Mine might be wrong but they are BETTER. Paul Beardsell 19:42, 7 May 2004 (UTC)

...

... if you want an accurate comparison with a space elevator, you need to compare to one that is at the very least man-rated and reentry capable. Do you accept this?

Depends upon the project. If we use the safer, more expensive rocket for people and cheaper, less reliable ones for [unmanned satellites], that allows for cost savings. Do you accept that? Paul Beardsell 19:42, 7 May 2004 (UTC)

You speak as if NASA had a choice. The technology of the day is the rocket. NASA are not foolish to use that, nor are they foolish to look at alternatives, howevr outlandish. I assume you mean "foolish enough not to look at alternatives". Yes - and almost all of the methods to get cheaper access to space do *not* involve rockets. Because rockets have *not* been getting cheaper, despite all of our advancements, and there is no way forseen to do so. They are investigating scramjets (so that the lower stage can be air breathing). They are investigating ballistic and electrical launch mechanisms (HARP, ram accelerators, rail guns, etc). They are investigating magnetospheric acceleration. And, more distantly, they are investigating space elevators. And the results *have* been good. Here, let me quote:

"The massive size and complexity of the space elevator concept is often cited as making such a system impossible to ceonceive except in the realm of science fiction. More detailed analysis of the system indicates that it is indeed very complex, but is comparable to other Earth-based infrastructures that have been built." It then goes on to compare to other Earth-based systems which are deemed to be of comparable difficulty, such building the Panama canal. Their pros and cons section has, number one: "The space elevator is one of the very few concepts that may allow Earth to orbit launch costs less than 10$/kg." They cover the many pros and cons, although I strongly disagree with some (such as "a catastrophic failure of a space elevator could produce ... ecological disasters with massive loss of human life" - yeah, maybe if you build it out of kevlar or some other comparatively low-strength material .... although you'll notice from several other cons and in the solutions section, they're considering such materials (as low as 20GPa!!!!!), which, honestly, an elevator will never be built with - the economics just don't work out). They recommend significant further study, with it flagged as a realistic possible candidate for the latter part of the 21st century. Rei 19:11, 7 May 2004 (UTC)

Less than $10/kg marginal or inclusive of capital cost? You must be making the SAME mistake again. At $5bn typical estimate for capital cost that would be 500,000,000 kgs before we start paying for the electricity. I.e. that figure was the marginal cost and is 7 times your $1.74 figure. Paul Beardsell 19:42, 7 May 2004 (UTC)

IN FIFTY YEARS - where in the article does it say that it will be built tomorrow? Of course there is a significant time frame - we need to get the tensile strength of nanotubes exhibited on the microscale on the macroscale. Few doubt that this is possible - the question is when it will be achieved. Certainly it's going to be more than 10 years from now. Probably more like 20 or more before it is achieved and cost effective. But such materials will exist in the future. And when such materials exist, a space elevator *does* become a very realistic, cost-effective structure. Even if such materials also improve "conventional" rocketry by a sigificant amount, it still doesn't stand a chance of being cost-comparable.

That does not follow. The 25000 is all inclusive. (Assuming you mean the shuttle's 25000): No, it isn't. It doesn't include a dime to recoup research costs; and, because it is used so much, the original construction cost is insignificant compared to the turnaround cost. I've mentioned this several times.

Shuttle? How many times must I say that is what it costs on Ariane V all in! That is what it costs to put your pet science project on the rocket. Paul Beardsell

Cutting costs, according to you, is impossible. Now that it seems it is possible you don't want to do it.. Oh please, you know very well what I meant. You can always sacrifice safety by cutting costs. We could try to send the shuttle up right after landing. It'll blow up, but hey, we can do it. I was mentioning that with as poor of a track record as the Ariane-5 has, cutting costs (and sacrificing safety) would be a Bad Thing(tm).

Depends upon the project. Then you need two sets of numbers. You are currently comparing the best case. The "worst case" with rockets - where you need to fling something as far out as, say, Saturn - has a *huge* amount of difference. Should we list the savings for transfer orbits?

Less than $10/kg marginal or inclusive of capital cost? You must be making the SAME mistake again. *I* must be? All I did was quote.

At $5bn typical estimate for capital cost that would be 500,000,000 kgs before we start paying for the electricity. Psb, you're driving me crazy. You know very well that this is the *BASELINE*, and that I welcome the concept of including full economics figures. However, since NASA isn't recouping the R&D with the shuttle launch costs, the ESA isn't with its R&D for Ariane-5, etc, it is *wrong* to include it in the section of rocket comparison.

So you say but you are seemingly struggling with total vs marginal cost. I would turn that statement around, since you seem to think that, with a 500-600m$ turnaround on the shuttle, that the development cost is being repaid. Do the math. The money to develop the shuttle is not being paid in there. The shuttle (excluding the time after the replacement of the external tank in 1998, which is not included in the launch cost) is 24,400. Divide, say, 550,000,000 by 24,400... and you get... ? 22541$/kg. Now, some of this money is administrative and refinement, component testing, etc - SSC gets 10m$, Goddard gets 483k$, HQ gets 3m$, etc, etc; but you get the picture.

I did it to draw attention to it. If bold had not been available I suppose I could have added "(ha ha ha)" afterwards. It's not a joke. That is the baseline. The baseline not only has the fact that it is a baseline mentioned, but has it emphasized with the fact that no proposal gets near the baseline. I did that, and I find it insulting that you are acting like I'm trying to hide some sort of secret to make a space elevator look better. If there were a single, *But There Isn't*. We can only fairly address this by putting in an economics section that covers one set of calculations for one particular design.

To remedy this, do you want to sum up the calculations in the Edwards report, do you want me to, or do you want to sum up the calculations in a different report? Rei 21:20, 7 May 2004 (UTC)

Economics Case Study 1 - Satellite launch

It's 2054 and the Namibian Telecommunications Agency senior civil servants have been reading Wikipedia. They persuade the Minister of Telecommunications that the NTA now needs to launch its own 1000kg satellite. For arcane budgeting reasons they would like the quote in 2004 US$. They first approach the ESA who explain that cost savings have unfortunately not been possible since 2004 so the price is the same in 2054, expressed in 2004 US$, as it was back in 2004. The NTA says stop mucking about, how much? $25million. The NTA gulped and hurried away.

How much to use the Space Elevator, they ask NASA? The answer was confidentional but was significantly above the $1,740 budget. But how much more?

Paul Beardsell 20:44, 7 May 2004 (UTC)

I'm not getting what you're trying to say, apart from "I think the space elevator will be more expensive without backing it up". Go read some Edwards or something. Hasn't that bothered you? The fact that you're debating something that you haven't even read a paper on? No? Rei 21:20, 7 May 2004 (UTC)

You've read it, you tell us. Why not? Paul Beardsell 21:41, 7 May 2004 (UTC)

I'm trying to get you to read it. You're insistant on debating about this subject. Why do you refuse to educate yourself on the subject? Engineering projects aren't simple. Read about it before debating. In case you lost it, here's the link again. Rei 21:56, 7 May 2004 (UTC)

I have read it. But I want you to tell us the figure because every figure I quote is wrong. Paul Beardsell 22:03, 7 May 2004 (UTC)

... The design is to build a cable whose climbers carry a 13t payload. Now, this system's primary use would be to build a much larger cable for mass-scale colonization and exploration, but lets just pretend that we're going to stop building and start launching satellites at this point. And, while all future elevators will be far cheaper, lets just pretend that we only have the original, most expensive one. Lets say we want to pay back our investment in 10 years. 40 billion dollars - cheaper than the cost of developing the space shuttle, in modern dollars. 13 metric tons every ~four days = ~90 launches = ~1.1 million kg per year = ~11 million kg in 10 years. ~3,400$ per kg - about the rate which is often cited as where many different economic possibilities begin to open up, and about 1/8th the cost of a shuttle ride, and far better than anything on the drawing board.

Now, lets stop with the ridiculous handicapping assumptions. Lets start by taking one off: we'll 10x the size of our cable (we'll be nice and make all of the subsequent size all be at the "second cable" price, even though it keeps plummetting from there). That's a little over 1,000$ per kilogram, and you're completely paid off in 10 years. What if we do our accounting like a real space program? Since launch costs on the shuttle, on Ariane, etc, don't include the development cost, it is unfair to do the same here. What happens if we do the same? Well, using Edwards's design, operating costs for 10 years is 1.56 billion dollars for a single 13t cable. That's 142$/kg. I have some disagreements with Edwards's design, such as not using up-only climbers; while it lowers throughput some, it saves both on energy costs and climber costs, dramatically reducing maintinence; on the other hand, I'm less optimistic about the power transfer efficiency. But, anyway, we won't get into this stuff; you get the idea of a general range. Rei 23:17, 7 May 2004 (UTC)

$142/kg? At 2% efficiency the electricy costs are 1.74*50 or $87. I think the operating costs do not include the electricity. What do you think? Paul Beardsell 00:59, 8 May 2004 (UTC)

The link to the Edwards study is just a few paragraphs above, and also right here: [1]. I think you can read it and find out quite easily whether the operating consts include electricity, if you want to know. Bryan 01:06, 8 May 2004 (UTC)

I can't work it out from the reference given. I can't see an estimate for the oil /gas for the generating station. Paul Beardsell 18:15, 10 May 2004 (UTC)

They provide the 10 year operating costs. FYI, electricity at the grid rate goes for about 10 cents per kilowatt hour. Rei 18:58, 10 May 2004 (UTC)

It was not obvious (to me) from the Edwards paper that the operating costs include the electricity costs. We know that much of the operating costs will be incurred if the number of elevator trips was halved or doubled. Paul Beardsell 19:18, 10 May 2004 (UTC)

AutoCAD Rocketry (very) Limited got its dubious tender under the door just before midnight: $2.5million. Paul Beardsell 20:55, 7 May 2004 (UTC)

What is that supposed to mean? Rei 21:20, 7 May 2004 (UTC)

It was meant as humour to lighten things up a bit. These are the guys you think are cowboys but (miraculously?) they have done what they said and reduced costs by an order of magnitude. Actually they've reduced costs to $1300/kg (as claimed in their paper) and are making a helluva profit because, although the elevator is cheap, Otis can't keep the doors from sticking. Paul Beardsell 21:41, 7 May 2004 (UTC)

But they didn't build a darn thing. They talk about building things, and put absolutely no detail into it. They assume that you can make a V2 reach orbit by spending 10 times more money (with no specifics). You can't. If it were that simple, every country and a few large cities would have their own space program. It's not remotely, even the tiniest bit, that simple. It is all completely uneducated speculation not worthy of the few kilobytes of disk space it's written on. The V2 was cheap not because it was "mass produced" more than conventional rockets. The V2 was cheap because it was a mere SRBM, built with slave labor. ... Rei 21:54, 7 May 2004 (UTC)

Y'know, that is what they were saying in 2004. But by the time the elevator opened in 2054 (amazingly they were on time but the budget had been blown!) the elevator had significant competition from AutoCAD Rocketry. And AutoCAD weren't the only players: Wwoods Inc was nearly as cheap. Paul Beardsell 22:00, 7 May 2004 (UTC)

Oh, I get your joke now. Ha. ...

---

Y'know, I will try very hard (but I will fail) not to say "I told you so" when someone comes up with some more authoritative source for reducing rocketing costs. Paul Beardsell 23:55, 7 May 2004 (UTC)

Justification of the Space Elevator

As I suspected (and as you all knew) it seems that the economic justification of the space elevator depends on lifting a whole lot more stuff into orbit than we currently do. If all we want to do is to have GPS (and the new Euro equivalent) and telecoms and weather forecasting and infra red astronomy and the occasional probe to the rings of Saturn then the financial justification of the elevator is difficult.

So, what is the elevator for?

Can we not remind ourselves that the solar system has no other planet which is habitable on economic grounds. That no nearby star has a habitable planet. That we could do a lot with US$40bn other than build an elevator.

Paul Beardsell 23:55, 7 May 2004 (UTC)

Holy potatoes, I spend a day away from Wikipedia and this talk: page doubles in size to 100 kilobytes. Sorry I left you to do all the heavy lifting, Rei. Anyway, Paul, the purpose of a space elevator would be to lift a whole lot more stuff into orbit than we currently do. Do you think the only things that can be done in space are the things that we've already been doing for the past few decades, launching handfuls of small robotic satellites and probes? There's tons of other stuff that could be done - colonization of the Moon, Mars, and other bodies (just because you can't walk around in shirt sleeves doesn't mean they aren't habitable, it simply requires more work to live there), the construction of solar power satellites, etc. If all you want to do is what we're already doing then of course a space elevator would be pointless; the whole point of having a space elevator (or other cheap "mass transit" system for getting stuff to and from orbit) is to expand the scope of the things that people can do there. Bryan 00:13, 8 May 2004 (UTC)

And I thought I (or we) had annoyed you into staying away. Recently I have wanted to reflect in the article that in order to justify the elevator that we must want lift a whole lot more mass than we do. I have been frustrated in that. Paul Beardsell 00:23, 8 May 2004 (UTC)

How much mass *did* we lift into orbit last year ? -- DavidCary 17:23, 11 May 2004 (UTC)

You want a justification for cheaper access to space? Here's one: Gold, silver, platinum, rhenium, and other rare metals. There are several hundred near earth metallic asteroids with an average 1.4 *trillion* dollars worth of rare metals in a form far purer than is typically ever found on earth (due to the way that they're formed). Even better, asteroids are often relatively poorly held together, and if they have any significant rotational momentum, mini-elevators (made out of materials as mundane as steel, and only a few miles long) can toss the mined material back to earth with no energy required, and power can be generated by tossing junk out into space. Even with conventional lift costs, this is being seriously considered. With low lift costs, it would be a *huge* industry. Rei 00:35, 8 May 2004 (UTC)

Economics NPOV

I dispute that any reading of the current version of the Economics section allows it NPOV status. My issues are

• It reads as if no capital or turnaround costs are recovered from the currently charged launch costs.
• If any figures have been given in support of this assertion they are shuttle-only figures - rocket figures are not given.
• Ariane 5 fuel costs are in the same ballpark as (or better than) the elevator electricity costs once the Edwards inefficiency figures of 2% or worse are factored in. The cost of fabricating the rocket does not account for the remainder of the $25,000 cost. So (at least some) turnaround/launch/capital costs are in there somewhere.

Paul Beardsell 18:11, 10 May 2004 (UTC)

... 1) The shuttle and Ariane DO NOT include their capital costs in their launch cost, so it is completely unfair to do so here. I've already demonstrated this to you concerning the shuttle - lookup their turnaround cost (I already quoted it), look up their payload (also quoted), and do the math. 2) If you want me to do the math for the Ariane as well, I will, but I can guarantee you they use the exact same scheme. 3) It's not just fuel costs. There are tons of cost associated with the turnaround. ... there is a reason that rocket launches cost so much? The implication of your argument is that all of the collective brain trust of the USA, USSR, ESA, Chinese, etc, are just fools for not seing this. That is not the case.

In short, we have a development cost around what the shuttle's development cost was (in modern dollars). We have the same accounting system as the shuttle. The Ariane works similarly. What is the problem? Rei 18:58, 10 May 2004 (UTC)

Once again you put words in my mouth: I did not say it's just fuel costs. I acknowledged, if you read what I wrote with the slightest care, there are other costs. But you make unsupported assertions. Feel free to do the maths for the Ariane. Surely it is the intellectual duty of they who assert the elevator is cheaper to properly back up their assertions. I did not introduce the Economics section here. But if it is here it must be NPOV. Oh, and as I have to say every time: I have not said anything about the Shuttle costs. Paul Beardsell 19:29, 10 May 2004 (UTC)

Metadiscussion:this whole talk page is not as messy as it used to be.

Metadiscussion:this whole talk page has become a colossal mess. (User:Bryan Derksen)

Boy, hasn't it. How about wiping archiving the whole thing and starting over, with a set of disputed topics, e.g., ==marginal_cost/kg via an Edwards skyhook==, ==... via an advanced elevator==, ==what is the minimum traffic level needed to justify an elevator?== How about taking longer turns, with sceptics and boosters posting on alternate days?

But it seems to me that webpages are suboptimal for presenting multiple involved discussions with multiple participants. People insert and/or append responses, and the ::: thing is quickly overloaded. How about moving the discussion to sci.space.tech or some such? I'd be much easier to keep the threads and subthreads straight, and we could get some new participants, with maybe some new perspectives. It's not true that all knowledge is contained in wikipedia (not yet, anyway).
--wwoods 08:06, 12 May 2004 (UTC)

I very nearly did that yesterday, I had the page nearly cleaned off into /Archive 2 in edit windows but I chickened out before pressing "save page" because I didn't want to be quite that bold. :) However, since I take this as a "seconding" of the idea, I think I feel more confident in doing that now. I'm going to move the bulk of this talk into Archive 2, and if there are unresolved issues that get moved with it I suggest that the proponents of those issues please restate them in a more organized way. Also, in future when this page gets too long let's be more careful about how it gets trimmed down; we shouldn't be snipping out bits and pieces of discussions, instead leaving or removing them whole-cloth. Bryan 15:27, 12 May 2004 (UTC)

By all means include a general comparison with rockets here. But don't spend whole paragraphs exploring the details of rocketry economics behind those general figures, instead say "for a detailed breakdown of these costs, see rocketry" and put them over there. If there's disputes over those details, then talk:rocket would be the appropriate place to work them out. Bryan 00:26, 13 May 2004 (UTC)

I moved stuff relevant to rockets over to Talk:Rocket, as suggested by Bryan. I hope some of it might be useful enough to move to the Rocket article. -- DavidCary 14:50, 13 May 2004 (UTC)

I moved stuff relevant to rockets over to Talk:Rocket. Again. I moved stuff relevant to the Van Allen radiation belt over to Talk:Van Allen radiation belt. Please edit those talk pages and move the facts out into the articles where they belong. Thank you. -- DavidCary 10:22, 27 May 2004 (UTC)

Economics: Where did these numbers come from?

I moved all the discussion of economics to Talk:Space elevator economics. -- DavidCary 18:51, 1 Jun 2004 (UTC)

Rocketry Capital Costs

(moved to Talk:Rocket)

Reversions of Wolfkeeper's Contributions

I have read Wolfkeeper's references and they seem as authoritative as any produced here. Certainly a lot has been said by others without references being produced. It seems to me profoundly wrong to remove information from the page which is backed up by references. Not only wrong but against NPOV Wikipedia policy. Rei you must find another way than just reverting back past info that does not agree with your POV. Read NPOV. Paul Beardsell 00:26, 25 May 2004 (UTC)

Rei, you have now reverted 4 times - against Wikipedia policy - and this is the last comment provided: It's not a POV, it's false "facts" which have not been defended on talk. Until they are defended, it is information that has been challenged without rebuttal. What seems to qualify as a "false fact" is something not said by you. Wolfkeeper has provided references. Your so-called rebuttal, in the above section, is without a citation to back it up. There is nothing for Wolfkeeper to defend - he has provided references. You have supplied some text which may or may not be true. References please. Paul Beardsell 00:41, 25 May 2004 (UTC)

False information is not a POV. It is false information. Should I go over to the page on the Moon and take the "Point of View" that it is actually an alien space ship plotting to destroy the world, and then start reverting it when people say that it isn't?

No. But you would be asked to provide a reference. The reference would be subject to scrutiny. And your moon POV is plainly false and would be very much a minority POV, whereas here, in this dispute, you must think there is a conspiracy against your POV: How can so many be so wrong, you must be thinking. Paul Beardsell 01:21, 25 May 2004 (UTC)

Yes, I think the correct wikipedian way is to include both POV. Deleting other people's opinions is considered gauche at best. It also says you are insecure enough in your own arguments that you don't think your arguments will be believed, it's a sign of immaturity (IMHO). Rei is actually holding it up here as if it is a good thing... small wonder she failed the admin vote I think; she isn't feeling the wiki, she so isn't.

His reference uses outdated dollar and payload figures in many cases. Some of the new rocket systems which should be considered "under development" (such as the Long March 2E, which is still struggling with a lousy 71% success rate) currently are cheaper than 10k$, but the shuttle would be that cheap also if we didn't inspect the tiles each turnaround  ;)

Here we have you admitting a lower cost than you will allow in the article: Make the reliability point in the article if you will. But it seems you are not being consistent. Paul Beardsell 01:09, 25 May 2004 (UTC)

As for citations, for God's sake, Psb, learn to use google and site:astronautix.com. I'll do your work for you this time [2] [3], but you have to do it yourself next time. And you're hardly one to talk about wikipedia reversion policy. Rei 00:48, 25 May 2004 (UTC)

Rei, it is your job to backup your own argument. I cannot see how your refs back up your POV. Perhaps a page or a line number? Or a quote. Paul Beardsell 01:14, 25 May 2004 (UTC)

I have once broken the reversion policy but once it was pointed out to me I never did it again. How long have you been aware of the policy, Rei? Paul Beardsell 01:04, 25 May 2004 (UTC)

That the information is or is not false is the question. Your argument is circular. Paul Beardsell 01:04, 25 May 2004 (UTC)

I refer you to the Third Commandment. Paul Beardsell 01:04, 25 May 2004 (UTC)

LEO transfer orbit

One of the candidate versions of the article now says that an orbital launch to 180km at 51 degrees inclination is a "LEO transfer orbit" - an unusual term! An orbit at 180km altitude is a good LEO. If any part of it is higher than 180km then that is even better. But the 51 degrees refers to the angle at which the satellite crosses the equator - it does not make the orbit elliptical. Paul Beardsell 00:54, 25 May 2004 (UTC)

It's gone now, but for clarity: If 180km altitude can be attained at 51 degrees then, given a better launch site a higher altitude can be attained (or more payload lifted) for the same cost. Paul Beardsell 01:50, 25 May 2004 (UTC)

More than that: reducing the payload size slightly raises the orbit, and only slightly worsens the cost/kg ratio.

Basically this term 'leo transfer orbit' is spurious unless it's at seriously low altitude (like 100km). Any orbit that goes around the earth atleast once is LEO by definition. Wolfkeeper

Van Allan belt problem

What's the solution to this? On the face of it we have mutually exclusive solutions. The focus in the Economics section is the Edwards proposal, an up-only elevator, but the proposed solution (in this article) to the Van Allan belt problem is portable shielding shifted about on an up-down elevator. An up-down elevator reduces by a large factor the payload capacity (it seems difficult or impossible to have multiple climbers and decenders simultaneously - difficult enough that Edwards did not want to solve it) and thereby the economics are significantly affected. Maybe we send cargo only and the astronauts go by rocket? Paul Beardsell 13:49, 25 May 2004 (UTC)

Yes, my understanding is that the Edwards plan for the first space elevator is a up-only, cargo-only elevator, without any shielding. -- DavidCary 10:22, 27 May 2004 (UTC)

(details moved to Talk:Van Allen radiation belt)

General Editing Principles

Look, houserules. You can stick more or less anything you want in the Space Elevator section; but you'd sure as heck better have a citation; no citation and I'm unilaterally editing it out again. The point of a wikipedia is you don't 'make shit up'. Some people appear to be doing this.

So I'm currently expecting a citation to Rei's scheme for sheilding the cars- if she can't produce it I'm removing it. (I don't actually think this scheme works- the worst of the belts are at low altitude anyway, where the cable is weakest).

As for deleting other people's contributions; if you have a *well* respected source, then it's barely ok, but you're better off adding in the contrary citation. And it had better be a primary source, not some airy-fairy 'rockets are all so inefficient and expensive opinion piece' or 'space elevators are impossible' or some such. Got it? Wolfkeeper

Meaning of "reality"

Recently the 2nd para was changed to say the SE "might become a reality in a little over a decade". This calls into question the meaning of the word "reality": It does not mean "realistic proposition". I reverted to "might become a reality in decades to come". Paul Beardsell 20:25, 26 May 2004 (UTC)

Actually that was me; I had neglected to log on. Apologies.

Let me explain. The only known showstopper for the space elevator is the cable.

This is a fierce research area for a whole host of reasons, not just for space elevators, but suspension bridges and a massive list of other possible uses of carbon nanotubes; including better and cheaper rockets :-)

If the cable technology was to appear in the next two years; that would not particularly surprise me; the current record of 10 cm at 63 GPa is *incredibly* close to being enough; the theoretical strength estimates are about 120 Gpa right now. OTOH if it didn't turn up for a decade or ever; that wouldn't surprise either.

Brad Edwards has a project plan that shows going from zero to elevator in (IRC) 14 years. It seems reasonable that it won't take much less than this, even if some sort of space race happened, but of course could take a lot longer.

So this is not necessarily decades off. So I think this language is justified.

Besides it's only the opening paragraph, having a few 'could's and 'maybe's and 'might's is fine. I don't agree with 'would's and 'will's though. --Wolfkeeper 22:39, 26 May 2004 (UTC)

C'mon now: Let's at least say something in the introduction with which we all can agree. If we are not going to have the bland version I propose then, Wolfkeeper, at least you mustn't delete Rei's references as this is something of which you yourself complain. Paul Beardsell 20:22, 27 May 2004 (UTC)

Yes, I certainly can see why you are complaining, and I'm not terribly unwilling to change it back, but I think that the opening paragraph *must* be positive, we want the reader to read the rest of the article; rather than just instantly dismissing the idea as silly. I made it clear that the people who think that are optimistic, and I personally do believe that the seed elevator might become a reality in a little over a decade. It probably won't; but it might; I'd be betting on 20 years even if the cable popped up tomorrow by the time it was financed; even the channel tunnel took 200 years to complete. It really critically only depends on the cable technology; the rest looks doable. Whether it stays up; more than 5 minutes I don't know. The one thing financially in it's favour is that people *love* the idea of a elevator; so financing might well be twisted out of the scrouge-like politicians or some rich entrepreneur.--Wolfkeeper 21:13, 27 May 2004 (UTC)

The showstoppers are not currently limited to just the cable. We have to be able to move LEO satellites. Paul Beardsell 20:22, 27 May 2004 (UTC)

Huh? What satellites? What are you talking about? Please explain--Wolfkeeper 21:13, 27 May 2004 (UTC)

Have you not even read the article that you're editing? (It would make a lot of sense, since you've been adding in a lot of redundancy in places).

You seem to take everything very personally and then you insult people- whilst assuming that other people do not take your insulting and offensive behaviours personally. Given that; you are likely to find your time in wikipedia very frustrating and annoying I think.--Wolfkeeper 01:07, 28 May 2004 (UTC)

Let me sum up: Every object in orbit between LEO and GEO has an orbit that will *eventually* intercept the space elevator.

Oh that. But, because the elevator moves, this doesn't constitute a show stopper; does anyone have a showstopper?--Wolfkeeper 01:07, 28 May 2004 (UTC)

While this collision will be a relatively rare event, the number of objects in space is quite high, and has been constantly increasing. Consequently, either the elevator has to move (as per Edwards), or all of the aforementioned objects must have maneuvering capability (of which many don't, especially defunct satellites and debris). Rei 21:23, 27 May 2004 (UTC)

Yes, yes, it moves; and sometimes it falls down anyway; which incidentally makes the economics worse, since it becomes maintenance not capital costs.

Incidentally some research I've read shows that the type of lasers for powering elevator cars can do double duty for clearing away space junk- if you can target it; and if it isn't cloudy that day.

Sorry that you find it insulting when people have to explain to you the parts of the article that you didn't bother to read before editing.

Sorry if you think that's what happened.

I hope it bothers you that other people are having to read for you.

Obviously that's what would happen when I asked what he meant when he said: "We have to be able to move LEO satellites.". I hope you didn't do any totally unnecessary reading Rei, that would be too sad. Everytime Rei does unnecessary reading... an Angel in heaven... dies.

Not every elevator design is designed to move; many are stationary.

And it's unclear why they would be practical; hoytethers are not a panacea.

Edwards' design happens to move. As per lasers, a space broom has notably different requirements,

No, not really.

and the elevator needs its power (that's what the laser is there for).

These objects won't be over the horizon for long; and if it is predicted to hit another object you'd do much better to take it out early than try to dodge the tiny fragments.

And your "sometimes it falls down" remark is just silly;

Not so; a sufficiently large micrometeorite will cut the cable entirely; also upon being struck the cable will tend to explode; some of the shrapnel will cause secondary damage.

all designs call for engineering within a tolerance so that this doesn't occur.

Not so. At best you can design it not to happen more often than every 100 years on average; or some such number. Same way they design buildings for a hundred year storm.

You might as well argue against building bridges because "sometimes they fall down". Rei 16:37, 28 May 2004 (UTC)

Amazing how you managed to make it sound as if we weren't on agreement on this point.

Economics detached from main article

I moved the economics section to space elevator economics and replaced the section in this article with a short summary. This is not an attempt to get rid of the current dispute by hiding it in some obscure place. I moved it because 1) the section was getting very detailed, and 2) this article is too long and should preferrably be partitioned even further. The fact that the economics dispute can now get a talk page of its own is merely a fortunate side effect :)

Feel free to improve my summary. It was a quick work and doesn't do as good a job as it should do. But try to keep excessive details out of it. The separate article can now be expanded to include every conceivable cost detail, this summary should be kept brief and abstract so a casual reader can get a good overview without getting confused. I find the current economics article rather confusing to read myself. Fredrik 22:46, 27 May 2004 (UTC)

Incorrigible optimists

See what the incorrigible optimists have been reading. Paul Beardsell 00:50, 29 May 2004 (UTC)

Perhaps you could point out what the relevance of this link to space elevators is? There doesn't seem to be any. Bryan 05:56, 29 May 2004 (UTC)

Well, it seemed to me that there is a certain parallel between the naive optimism which is being gently but appreciatively poked at that web site and the barely-a-decade optimism here. Failing which I hoped that the web site would be appreciated for its own sake by those who have a sense of humour, regardless of their position on the optimism scale. It can't be that a defining attribute of the space elevator enthusiast is a lack of a sense of humour? Paul Beardsell 00:45, 30 May 2004 (UTC)

Perhaps my sense of humor is worn thin on this particular topic, but my sense of irony isn't. I note that most of the "incorrigibly optimistic" methods portrayed here are rocket-related. :) Bryan 03:02, 30 May 2004 (UTC)

The link doesn't even appear to work... 404?

Works for me. You are clicking on "reading" in the 1st para of this section? Paul Beardsell 01:31, 30 May 2004 (UTC)

Ah got it- Mozilla gives 404, but Internet Explorer gives a cheesey 1950's style page. Kinda weird that the two browsers give different results to that extent.

Works on Mozilla (1.6) for me. Paul Beardsell 16:06, 30 May 2004 (UTC)

FWIW I'm using Mozilla (1.7b)- don't know why that would matter. Reproducibly works with IE version 6. Reproducibly not working with Mozilla 1.7b under windows XP.

carbon nanotubes

Hmm. In all fairness you'll note that space elevator designs currently rely on currently non existent [ carbon nanotube ] cables, whereas rocket cost reductions mainly rely on launching more often, using better engineering and architectures, using actual past experience; and avoiding being part of a national program as they usually don't care so much about money. Wolfkeeper

I moved discussion of carbon nanotubes to the Talk:carbon nanotube article -- DavidCary 18:51, 1 Jun 2004 (UTC)

characteristic length

Someone needs to fix the engineering discussion in the Cable section. The feasability of constructing a space elevator isn't determined by the material's tensile strength, it's determined by the ratio between the material's tensile strength and density. If someone discovers 120 GPa Unobtanium tomorrow, it'll still be useless for a beanstalk if it's as dense as gold. One of the reasons people are so excited about carbon nanotubes is the combination of low density with high tensile strength.

Yes, I agree. Since the "strength/density ratio" is the critical number, that's what we should be comparing between these materials. Another name for this number is the "characteristic length". Is it OK if I quote http://www.frc.ri.cmu.edu/~hpm/project.archive/1976.skyhook/1982.articles/skymes in the article ? -- DavidCary

A nice intuitive way to express the strength to weight ratio
of a material is called "characteristic length".  It is the length
of material fashioned into a constant cross-section rope that can
just support itself when hung from one end in a uniform one earth
gravity field. (The formula is  tensile-strength/(density*1g)).
Graphite, with its strong covalent carbon-carbon bonds is the best
actually existing material. Its theoretical characteristic length
is several thousand km.  A metastable metallic version of hydrogen
that can exist at room temperature might be quite a bit better
because hydrogen has much less dead weight, but its existence is
only conjectured.
.
Later editions of the CRC handbook have a NASA originated
table labelled "Mechanical and Physical Properties of Whiskers".
The indicated whiskers are actual laboratory grown, millimeter
length, single crystal rods of various substances, whose strength
and density can be measured.  The measured properties give the
following characteristic lengths:
.
Graphite whiskers	961 km
Al2O3 whiskers		527 km
Iron whiskers		162 km
Si3N4 whiskers		455 km
SiC whiskers		704 km
Si whiskers		337 km
.
These numbers are about 1/5 to 1/10 of the theoretical limits for the
substances.
.
By comparison we have todays engineering materials:
.
       Bulk aluminum		  10 km
       Bulk iron		  11 km
       Bulk steel		  40 km
       Nylon			  88 km
       Fiberglass		  98 km
       Kevlar			 195 km
.
As stated in my previous message, a strength five times that of Kevlar
would make earth elevator cables of varoius varieties possible. This
means a characteristic length of about 1000 km; a bulk material with
the graphite whisker strength above would do fine.

-- http://www.frc.ri.cmu.edu/~hpm/project.archive/1976.skyhook/1982.articles/skymes

It would be really, really nice if the above materials: aluminum, iron, steel, nylon, fiberglass, kevlar, silicon (Si), graphite, sapphire (Al2O3), silicon nitride (Si3N4), silicon carbide (SiC) -- as well as nanotubes -- had both the numbers we need for this calculation (tensile strength and density) in their respective articles. Unfortunately, most of them *only* list density; and nanotubes only lists tensile strength. -- DavidCary

Tensile strength has a table. Assuming tensile strength of 60 GPa and a density of 1.5 g/cm³ [4] gives a characteristic length of about 4,000 km. Another figure of merit is the characteristic velocity, sqrt(strength/density), which is not intuitive, but isn't tied to Earth's gravity either. Other refs: [5]
--wwoods 23:00, 12 Jun 2004 (UTC)

Why, in the quoted material above, is a characteristic length of 1000km good enough for a cable much, much longer than that? The first few thousand km of which will be in a gravity close to what we experience here on the ground. Paul Beardsell 04:40, 14 Jun 2004 (UTC) From your last reference I quote:

The support lengths assume no tapering.  He figures tapering would
be used, but a safety margin is also required, so they cancel out.
The necessary support length for a Terran beanstalk is about 4,940 km.
.
He mentions that graphite whisker is already strong enough for a
Martian beanstalk, where the support length is 975 km.

Paul Beardsell 04:44, 14 Jun 2004 (UTC)

The optimal taper (ignoring saftey margin) is exponential; the characteristic length is the length over which the diameter must increase by a factor of e. So even with constant gravity, you can get away with a few characteristic lengths before your cable becomes outrageously huge. (I assume this is part of what went into the 4940 km above; at such lengths decreasing effective gravity can help too.) --Andrew 04:51, 14 Jun 2004 (UTC)

Drag

The "Launching into outer space" describes drag on the cable (west ward0 when mass climbs. But it doesn't explain how the cable katches up after imparting orbit velocity to the payload. Pud 23:59, 25 Jun 2004 (UTC)

Yes it does. "This angular momentum is taken from Earth's own rotation." and "The horizontal component of the tension in the cable applies a tangental pull on the payload, accelerating it eastward. Conversely, the cable pulls on Earth's surface, insignificantly slowing it." - basically, the rotation of Earth pulls the elevator back up to its original momentum again, infinitesimally slowing down Earth's rotation in the process. I'll add the direction of the pull to the article, hopefully clarifying this. Bryan 00:29, 26 Jun 2004 (UTC)

• What is to keep the cable from being continually pulled back as more and more mass is lifted, what acts to straigenten it out and keep it verticle? Pud 00:38, 26 Jun 2004 (UTC)

The centrifugal force acting on the counterweight at the end of the tether. Since the elevator's center of gravity is slightly farther out than geostationary orbit, the elevator acts a lot like a rope being held onto by a spinning figure skater; it "wants" to stick straight outward, and if it gets nudged to the side it will swing back out again on its own. Bryan 02:46, 26 Jun 2004 (UTC)

• How about; "the verticle componant of the cable tension causes the cable to return to verticle after accelerating the launch mass" ? Pud 00:45, 26 Jun 2004 (UTC)

Sounds good, I'll work that in. Bryan 02:46, 26 Jun 2004 (UTC)

It won't necessarily return to the vertical--if there's a constant (net) flow of mass along the cable, the Coriolis force'll impose a permanent incline to the cable. Not much--it's like a rope being held by a spinning skater, along which ants are crawling. The tilt sets one limit on the throughput of the system, but it's not a problem, as long as the center of gravity isn't pulled down below GEO. Of course, by varying the movement of mass along the cable you can make it swing and shimmy; that's the way proposed to avoid some collisions.
--wwoods 08:45, 26 Jun 2004 (UTC)

Another good point to work in :) Bryan 16:52, 26 Jun 2004 (UTC)

Clarification requested

Moved discussion of various types of tethers, and what to name each one, to Talk:tether propulsion. --DavidCary 08:52, 11 Jul 2004 (UTC)

it seems the whole article uses metric, except for the "Building an elevator" section. i wanted to change it, but i realized i have no clue which ton is used. can somebody try to find out, and then change it to fit the rest of the article?

Economics article factual dispute still ongoing?

There's been a factual accuracy dispute tag over at Space elevator economics for two months without any editing being done on either the article or the talk: page, does anyone know whether the dispute is still ongoing? I asked in that article's talk page too, but I figured this page was more likely to be bookmarked by interested people. Bryan 18:34, 25 Sep 2004 (UTC)

I think pretty much everyone got bored by the bickering and people claiming that white was black, or that only orange is important. I know I got bored. -WolfKeeper

Anonymous Economic Evaluation

This anonymous IP (4.232.144.53(talk)) economic evaluation was moved from the main article page. It likely has some valid points, but it is too long for the main article. Also, it is written in first person, and talks directly to the reader in second person, both violations of Wikipedia style. Any valid points need to be summarized and put into the Economics section. If it is rewrittend and scanned for validity, it might be suitable for inclusion in the Space elevator economics article.

WERTMULLER'S EVALUATION This article - "Space Elevator Economics" - as presented before December 26 2005, was severely flawed.

First there was no consideration of dramatic improvements in alternative space technologies. For example, Bert Rutan's Space Ship One completed two flights to an altitude of 100 km and a speed of Mach 3 carrying a payload equal to three men at phenomenal low cost in just the past year. Space Ship One weighs less than 10 000 pounds. See Wikipedia "Scaled Composites SpaceShipOne". It is carried from the ground to a launch altitude of about forty thousand feet by a special mothership. Such "lift-launch" spacecraft are more efficient than simple rockets. Yet this technology was not compared at all to the space elevator. And "lift-launch orbiters" will surely be improved. Consider what Burt Rutan could launch if he leased and used the new Airbus A380 for his ground launch mothership. See Wikipedia "Airbus A380".

So the economics of other technologies has probably been mistated towards the high side. Meanwhile, the economics of the space elevator have undoubtedly been mistated on the low side due to mistakes regarding the basic physics of tethered space elevators. I will present the corrected physics here in this section. I recommend leaving the current mistakes in the "Physics" section unchanged so that new readers can comprehend what has transpired. The best way to understand everything is to perform "Gedanken" experiments......

You are floating in space in your space suit in absolutely perfect geosynchronous Earth orbit. You gently unholster your favorite weapon - a grenade launcher - and fire one off in precisely the opposite direction from Earth.

Conservation of momentum and energy together with Newton's Third Law means you move initially with a small constant linear velocity towards Earth. See Wikipedia "Newton's Laws of Motion". But you are in orbit! This means you have both linear and angular velocity relative to Earth. Your angular velocity is your number of orbits around Earth per unit of time - exactly one revolution per 24 hours at first. Your linear velocity in geosynchronous orbit is roughly 7 000 miles per hour - straight "east". You would fly off straight into space but gravity pulls you around in a circle. Newtonian physics dictates that this linear velocity remains unchanged unless some force changes it.

But you are moving closer to Earth because of the grenade so you are traveling around in a smaller and smaller circle around Earth. Smaller circle; Same linear speed. You circle the Earth in slightly less time. You are no longer in geosynchronous orbit.

Not correct. Due conservation of angular momentum around the Earth, you're still in geosynchronous orbit, but you've changed your eccentricity. (You're now in an elliptical orbit, but still with a period of 1 day).WolfKeeper 15:53, 27 December 2005 (UTC)

Good point but I am attempting to speak to non-physicists. Elliptic orbit still means "disturbance:.

You also are no longer "stabile". Since you travel around Earth in slightly less time, you have higher angular velocity hence higher centrifugal force. This higher centrifugal force throws you away from Earth counteracting the inward speed you got from your grenade. The grenade launch is actually a brief linear impulse which does not remain directed at the Earth's center as you fly around curving thru space, but we can ignore this non-Earth-centricity for a short time for simpler exposition with little error. In due time you stop moving in or out from Earth and stabilize in a lower, faster, non-geosynchronous orbit.

Sorry, not quite.WolfKeeper 15:53, 27 December 2005 (UTC)

The exact same forces occur in reverse if you push yourself away from Earth, that is, if you fire a grenade towards Earth. You would keep the same linear velocity in a larger orbit; lose angular velocity; lose some slight centrifugal actually centripetal force; and stabilize at a higher, slower, non-geosynchronous orbit. Changes in angular velocity with changing orbital altitude is directly related to the Coriolis Effect. See Wikipedia "Coriolis Effect".

DEPLOYMENT The forces described above greatly complicate the deployment of a tethered space elevator. Again we assume you are in perfect geosynchronous orbit. An alien from another galaxy drops off a complete space elevator kit without making the slightest gravitational wave or other distrubance. Following the included easily comprehended directions, you begin unwinding the thousands of miles of graphite ribbon. But the ribbon does not drop down to Earth.

No object changes its state of motion unless it is forced to do so. Newton's Laws. If you spin a reel of tether in space centripetal force will pull all the ribbon en masse off the reel in a tangled mess. It will not "unwind" like an elevator cable on Earth which is subject to constant gravitational acceleration - constant force. Hence some method of careful folding might be best when transporting space tether tape.

But then you must unfold it. It will not unfold itself. It will just "hang" there in orbit wherever some rocket unloaded it. Most likely you will use some kind of little rocket propelled tractor to pull the tape towards Earth. And you pull the other end away from Earth. And for every inch of movement, you encounter the exact same forces described above. Higher angular velocity in lower orbits destroying geosynchronicity. Rocket-propelled correction required. Continuously. During all unfolding and movement. Likewise lower angular velocity in higher orbit. Rocket firing will be required at both ends of the tape during all deployment movements. Thousands of miles. Hundreds of hours. Weeks. Months. A year?

The cost of this deployment operation was not even mentioned in the "Space Elevator" Wikipedia entry as it existed before December 26, 2005. And there is another cost underestimate which may be even more problematic. The December 25 2005 Wikipedia article contained these words:

"Launching Into Outer Space As a payload is lifted up a space elevator, it gains not only altitude but angular momentum as well. This angular momentum is taken from Earth's own rotation......"

The climber does not gain angular momentum solely from the Earth. Any object sitting on the surface of the earth at the equator is moving with angular velocity of exactly one revolution per 24 hours and a linear velocity of roughly 1 000 miles per hour. A satellite in perfect geosynchronous orbit also has an angular velocity of exactly one revolution per 24 hours but a linear velocity of roughly 7 000 miles per hour. Climbers do not obtain their velocity increase strictly from Earth. Every climber will distort the tape slightly and will pull on BOTH the elevator structure - including any counterweight - as well as the Earth. The climbers "want" to go "slower" slower angularlly as they go higher at every point. As climbers climb higher, more and more of this backward pull is levied upon the elevator and counterweight.

Yes.WolfKeeper 15:53, 27 December 2005 (UTC)

The backward pull slows the velocity of the entire elevator structure. The entire system - climber plus elevator - wants to rotate and "lie down" upon the Earth. The size of the backword force depends on how fast the climber climbs. If it goes up fast, it gains linear horizontal velocity faster which which requires greater horizontal force to create the acceleration. You cannot defeat Newton's Laws. A greater horizontal accelerating force on the climber means a greater horizontal retarding force on the Earth-Elevator system. The climber is accelerated to 7 000 mph and the elevator is correspondingly slowed, albeit less because of greater mass. Conservation of energy cannot be denied. The climber gains momentum and the elevator loses momentum. The elevator will have to be pulled back to proper velocity and position by a rocket motor firing at the far space end of the elevator during all climbing.

Actually, no. The elevator cable below the elevator car takes on a lean- about 1 degree at 200km/h. This lean means the Earth is pulling on the Space Elevator sideways, accelerating it. So the Earth is slowing minutely, as the car climbs. But the overall energy and angular momentum is conserved. So no rockets are needed. If the car was to go a lot faster it would be very different thing though; the elevator would indeed fall over if the center of mass went below GEO. Part of the design is to make sure that the center of mass is far enough above GEO that any likely lean on the cable will prevent it from 'falling over'.WolfKeeper 15:53, 27 December 2005 (UTC)

Actually yes. Anything other than a truly perfect geosynchronous orbit will be intolerable. It will degrade worse and worse. Truly perfect means circular and alinged with the equator. A perfectly circular orbit tilted with respecty to Earth's axis making figure eights in the sky will be intolerable. An elliptic orbit will be intolerable. And as the climber approaches the goestation, it DOES affect the station, not just the Earth. a geostation with a 100 000 km extended counter weight will never "fall" but in the most extreme case it will wrap the tether around the Earth a short ways while oscillating wildly. Not acceptable.

Thus both construction and operation of a tethered space elevator will be more costly than implied by the previous Wikipedia article.

There is an alternative. Attach a tether to the Moon instead of Earth. Allow a low orbit space station to "hang" close to Earth while dragged around from the Moon. The low altitude space station would be motionless relative to the Moon but would fly "backwards" relative to other Earth satellites. The Earth would be spinning around at a thousand miles per hour underneath the effectively motionless "satellite". Such a near-earth station would actually "hang" - it would not be held in place by centripetal force. The Earth would spin around every 24 hours below while the hanging station stayed motionless with the Moon. Low cost orbiters like Burt Rutan's Space Ship One could rendevzous with this slow moving space station just like fighter aircraft rendevzous with aerial tankers. There is still abundant uncertainty of cost and feasibility.

end of anonymous economic evaluation moved from the article page. Hu 09:37, 26 December 2005 (UTC)

Anonymous Economic Evaluation

I posted the "anonymous economic evaluation" and herewith present an improved entry. Dudes: Somebody gotta post this in the main article. The Institute for Scientific Research is very nearly committing criminal fraud. IF NOT SEVERE ERROR, THEN con artistry. Capiche?

ECONOMICS RECONSIDERED

The Wikipedia Space Elevator article as presented before Christmas 2005 underestimates the cost of a tethered elevator due to a severe error in the basic physical design. The previous economic analysis also underestimates progress made with other technologies. See Wikipedia "Scaled Composites SpaceShipOne" and consider the added implications of the Wikipedia article "Airbus A380".

"Space Elevator" Section 2.5 contains the sentence "The angular momentum is taken from the Earth's own rotation." This is the same as saying that a bridge with two uneven supports - one larger than the other - is supported only by the larger support, which is absurd. Increased angular momentum is transferred to a climber via the Coriolis Effect. See Wikipedia "Coriolis Effect". Any climber on a space tether will gain angular momentum from both the Earth and the tether structure. The effect on the space end of the tether will be to pull it down and backward. The tether / counterweight structure will be pulled out of geosynchronous orbit. To pull it back will require a rocket motor firing nearly continuously at the space end of the tether. This implies enormous costs for fuel and refueling.

Installation of a tether involves similar problems. A reel of carbon tape unloaded from the Space Shuttle in geosynchronous orbit will not unwind itself. One end must be pulled into space with some kind of rocket tractor and the other end must be pulled to Earth. At all points of this unwinding operation the rocket tractors must compensate for the very same Coriolis effects. Installation thus means many many hours of very precise rocket firing with attendent costs. You cannot defeat conservation of energy. The Space Elevator disguises the energy of space acceleration as Coriolis Effect.

One possible alternative is to deploy a tether all the way from the Moon to somewhere near the Earth. A space station then might literally hang near Earth. It would not be held up by centrifugal force. It would actually hang from the Moon. It would be motionless relative to the Moon. The daily rotation of the Earth would make it appear as if this station was flying towards the west at 1 000 miles per hour. Low cost orbitors such as SpaceShipOne could then rendevzous with this station and from there pull cargo all the way to the Moon. The Moon would sacrifice an unmeasureable amount of momentum.

May I suggest that a Wikipedia article's discussion forum may not be the optimal place for allegations of fraud or incompetence? You surely won't get many eyeballs on the problem. A better place would be the Yahoo SE mail list at http://groups.yahoo.com/group/space-elevator/ or Liftport's Forum at http://www.liftport.com/forums/

Note that ISR has been quiet WRT space elevator's since Brad Edwards departure. I am not sure what this means, or what import - if any - it has. brian dunbar

Thank you for your comment. I am sure you are right. The space elevator has garnered such enthusiasm; such attention; is a featured article; that pointing out catastrophic high-school level errors will likely be unwelcome. But needs to be said sometime. I doubt that fraud is the problem. Rather some kind of mania. That is why I try to offer some kind of alternate fantasy trip. Call them "Moonbelts". Maybe? -- HRW

Thank you again Brian for the news that Edwards left ISR. I do not know where to read news of this sort. Having just read wikipedia regarding 'Nanotubes' I suspect Edwards heard rumors inre nanotube strength and decided to quietly exit the wild, whacky, manic, traveling space elevator show. Therealhrw 04:03, 29 December 2005 (UTC)

Your post contains a number of errors. For one, keeping the space station in orbit would not require 'a rocket motor firing nearly continuously at the space end of the tether', as the space station is continually pulling the cable tout through centripetal force, as it is in orbit beyond the geosynchronous orbit you imagine. In light of such, rather obvious and glaring errors, it's hard to take your post seriously. Something isn't 'con artistry' simply because you do not understand it. -- Ec5618 10:15, 27 December 2005 (UTC)

No, no glaring error by HRW. Glaring error in Section 2.5. Thinkabout it. Coriolis force sideways at point of climber. 'Taut' tether like giant spring. SOME slight displacement - movement - in tether / counterweight system even tho 'taut'. NO displacement tolerable - not if there will be thousands of climber trips. You think space elevator disposable?.

Any displacement of the cable or the entire system is temporary, because the system will 'spring back', powered by the centripetal force on the space station. I'm sorry, but why do you so steadfastly believe that you have found a glaring error, when dozens of qualified scientists see no impassable hurdle outside of the required tensile strength in the cable? -- Ec5618 13:59, 27 December 2005 (UTC)

No, tether / weight system does not just spring back. As soon as you change position of stuff in orbit it starts to rotate - different angular velocities at different altitudes. I have wondered about the 'conspiracy of silence". Maybe publishers like Discover magazine want circulation and don't care about disinformation? Ever hear about Borna virus and mental illness? What happened there?

Climber Design

I offer another revision proposal for the Space Elevator article......

Wertmuller's Climber Design

Climbers could be equipped with sideways firing rocket motors to combat the Coriolis Effect. Some have argued that uncompensated Coriolis Effects would ruin the entire Space Elevator system, causing a loss of geosynchronicity thereby forcing prohibitevly costly rocket-powered realigmnment of the tether and counterweight. To avoid disturbing the tether / counterweight system, each climber could have a small sideways-firing rocket capable of exactly countering any Coriolis effects generated by the climber.

The most desireable propellants from an environmental view would be the components of the atmosphere - nitrogen, oxygen, or carbon dioxide. The quantities of carbon dioxide involved would be near nothing compared to ground vehicle emissions. One of these propellants could be stored in frozen liquid or solid form and then heated and expelled using electric power - from whatever power supply system is invented for climbers. If the carbon nanottube tether could be made conductive, alternating electric current could be fed into the tether at ground level and extracted by climbers thru capacitor banks at virtually any location.

A 5000 pound climber might have 4000 pounds of propellant and a 1000 pound payload. To completely avoid Coriolis disturbances, the rocket motor would be fired both when climbing and descending.

Dudes, you gotta face the fact that as it now stands, the Space Elevator article / design is outrageously wrong. As pointed out in my previous posts, the Earth alone does not drag the climbers to higher angular momentum. That is the same as saying only one of two supports carries all the load on a bridge. The climbers exert Coriolois force on both the Earth and the counterweight ((or vice versa)) thereby gaining momentum. And the slightest distuturbance of counterweight geosynchronicity will need to be corrected at some point.

Brian Dunbar I greatly appreciate your replies. I want to repeat that I am complaining about such a primitive, pivotal error that it ALMOST looks like fraud. But I lean strongly toward believing in outrageous error. It has happened before. Constantly. Seems to be something human...... Therealhrw 08:55, 27 December 2005 (UTC)

Please stop calling everyone 'dude'. -- Ec5618 14:03, 27 December 2005 (UTC)

Okee Doke. Call you Something Else Sir. --therealhrw.

OMG I just finished reading this brilliant indictment of the SE concept. And to think I just put my Liftport stock certificate in safety deposit! Not only is the space elevator a fraud, but so is basic physics! I call upon the participants of this talk page to join with me and Therealhrw to create our own physics and then create our own space elevator based on this new theory. Who's with me?!!! Plowboylifestyle 16:19, 27 December 2005 (UTC)

Climber Design II

A revision of my previous proposed main article revision:

Wertmuller's Rockets

Climbers could be equipped with sideways firing rocket motors to combat Coriolis effects. Some have argued that uncompensated Coriolis effects would ruin the entire Space Elevator system, causing a loss of geosynchronicity thereby forcing prohibitevly costly rocket-powered realigmnment of the tether and counterweight. To avoid disturbing the tether / counterweight system, each climber could have a small sideways-firing rocket capable of exactly countering any Coriolis effects generated by the climber. The required compensation is small. If a climber takes 100 hours to climb from Earth to geostationary platform, the necessary sideways acceleration is roughly 1/50 ft/sec/sec for the entire 100 hour (360 000 second) climb. To completely avoid systemic Coriolis disturbances, the rocket motor would be fired both climbing and descending.

The most desireable propellants from an environmental view would be the components of the atmosphere - nitrogen, oxygen, or carbon dioxide. The quantities of carbon dioxide involved would be near nothing compared to ground vehicle emissions. One of these propellants could be stored in frozen liquid or solid form and then heated and expelled using electric power - from whatever power supply system is invented for climbers. If the carbon nanotube tether could be made conductive, alternating electric current could be fed into the tether at ground level and extracted thru capacitor banks on board climbers. Such a climber might have 4000 pounds of propellant and a 1000 pound payload. An ion rocket engine with extremely high propellant exhaust velocity could reduce the amount of propellant required thereby achieveing higher overall efficiency.

If reels of carbon tape are delivered to geosynchronous orbit by some means such as the Space Shuttle when first building a Space Elevator, the ends of the tape would need to be pulled into position by similar high-efficiency, high-precision, long-burn rocket engines. The tape will not fly into position by itself. Supplying power to the the deployment tractor engines is much more problematic.

Construction And Decay

Wolfkeeper's replies regarding orbital decay and elliptic orbits are well made "Econonmic Evaluation". But it is a fact that climbers *will* affect the motion of the space end of a space elevator. A climber nearing the geostation will exert a negative acceleration (negative with respective to orbital motion) on the station / counterweight due to Coriolis effects. This negative impulse will add a slight negative velocity to the far end of the structure. The entire structure will "try" to wrap itself around the Earth, albeit imperceptibly at first. The connection of the tether to the ground will prevent continued westward motion leading to complex counter forces. These counter forces and continued westward impulses from climbers will lead to a complex decay of the position and motion of the elevator.

Nope. The car moves the geostation about 1 degree to the west of the attachment point; but the centrifugal (remember we're in a rotating reference frame, so centrifugal is 'real') acts directly away from the Earths axis. So there is a restoring force pushing the cable/station/car back above the attachment point on the Earth due to the non vertical component of the tension in the cable. It's also critical to remember that the geostation ISN'T in orbit. It's moving too fast to be in orbit, it's above GEO, and hanging on the cable, but rotating around the Earth axis once a day, so it goes further than an object in GEO per day- it's faster. By way of contrast, orbital velocity goes *down* the higher you are, since the gravity is lower there.WolfKeeper 01:58, 28 December 2005 (UTC)

If you say you are going to store so much energy in the station / counterweight system that all perturbations will be acceptably small even for so many - millions? - of tons of payload, you are saying you are going to fire rocket tractors for hours; days; weeks; months; hauling everything into place during construction and then use the stored energy later to climb into space without rockets.

Nope. Space Elevators are passive (except for the cars, and possibly moving the base around.)WolfKeeper 01:58, 28 December 2005 (UTC)

Why? Why not just fire a rocket when you want to go into space? Like Burt Rutan?

Burt Rutan's is suborbital. Space Elevators allow access to *GEO*.WolfKeeper 01:58, 28 December 2005 (UTC)

There remains the possibility of building uniquely efficient rockets either for construction or Coriolis compensation. This is the subject of my "Wertmuller's Rockets" proposed revision. Please read it. --THEREALHRW

Actually, as long as the elevator's center of mass is out beyond geosynchronous (as it is in all serious design proposals) you don't need to fire any rockets to keep the elevator up. The angular momentum imparted to the rising climber comes directly out of Earth's rotation, not out of "stored energy" put into the system during the elevator's construction. The tug of the tether's connection with the ground as the elevator "tries" to move west adds back the momentum that was given to the climber, restoring the elevator's orbit and preventing decay. Bryan 01:05, 28 December 2005 (UTC)

Please come off of your high horse, Therealhrw; you did not just find a major flaw in the concept of space elevators. 'Wertmuller's Rockets', indeed. Incidently, even if you had found such a flaw, it would constitute original research, and could not be included. Now please stop spamming this page with nonsensical 'theories'. -- Ec5618 21:21, 28 December 2005 (UTC)

Finally understand it. Thank you all for your patient responses. I dare not get off my high horse because if I do, intestinal gas esccapes. Therealhrw 03:18, 29 December 2005 (UTC)

Archive Anyone?

If no objection posted here in next couple days, I will attempt to create archive within this page; titled 'Newbie's Arguements"; and move all my spam-grade entrys and related replies thereto. This would be entries 29, 30, 31, 32 and 33. Therealhrw 09:30, 30 December 2005 (UTC)

I have no objection, though I would suggest an different description. Therealhrw's arguments, perhaps, or Therealhrw's newbie arguments. Just 'newbie' makes it sound like a repository for newbies, and something all newbies should refer to. 'One newbie's regretable arguments' might work, if you agree with the sentiment. -- Ec5618 00:30, 31 December 2005 (UTC)

I would prefer "Arguement With HRWertmuller" Therealhrw 00:54, 31 December 2005 (UTC)