Talk:Space elevator/Archive 1

Removed: NASA and the European Space Agencies should definitely start production of these space elevators if we are ever to exist as a race off of this planet, so that we dont put all of our eggs in one basket. Otherwise, this is great stuff! --MichaelTinkler

Whups. I got some of the text off of a NASA web page, I guess I didn't edit it carefully enough. :) I'll check it some more for NPOV now.

-

To answer the next question I'm sure a lot of Wikipedians will now ask, yes, the text is pretty much verbatim from an external source, which is usually a big no-no. I can't find an explicit copyright statement on the pages. But the page in question is part of NASA's "project liftoff", which is a fully tax-funded educational project, and is hosted on nasa.gov, which is tax-funded site, and while NASA makes a bit of noise about being a semi-independent non-government entity, recent court decisions have made it clear that they are an agency of the government with regard to regulations covering agencies of the government (they are subject to FOIA, for example), so it appears that we are safe from copyright problems. --LDC

Please quote a link to the page used as the basis of the article. Paul Beardsell 12:13, 1 May 2004 (UTC)


 * Good to hear a second opinion confirming my understanding of the situation. I did a bunch of editing on it as well, it'd be annoying to have it turn out to be illegal after all. :) -BD

How about using fibers made of synthetic spider silk protein? I heard spider silk is stronger than kevlar.

Unfortunately, I'd bet protein-based cables wouldn't hold up very well in the vaccum and hard radiation of space. Not to mention that spiderwebs have a high liquid-water content, necessary for their springyness and flexibility. A pity since it'd be really cool to string spiderwebs into space like that.

Shouldent this article contain some scepticism about space elevators e.g the potential downsides/risks/practical problems of a space elevators. This article reads like a space elevator promotion article at the moment G-Man 16:48 29 Jun 2003 (UTC)


 * Added a section on failure modes, is that the sort of thing you were thinking of? Bryan


 * The NASA report (http://flightprojects.msfc.nasa.gov/fd02_elev.html) (this link does not work) had a neutral discussion of the pros and cons. Astudent 05:19, 2003 Aug 16 (UTC)

"Artsutanov suggested using a geosynchronous satellite as the base from which to build the tower. By using a counterweight, a cable would be lowered from geosynchronous orbit to the surface of Earth while the counterweight was extended from the satellite away from Earth, keeping the center of mass of the cable motionless relative to Earth. Artsutanov published his idea in the sunday supplement of Komsomolskaya Pravda (Young Communist Pravda) in 1960."

Call me dumb, I can't seem to get the counterweight thing. Where would the opposing force (away from Earth) origin? I know some basic newtonean physics but this sounds weird unless there's some propulsion system (or another planet with sufficient gravity) to pull the (long!) extention towards space -- Rotem Dan


 * The opposing force is centrifugal. By extending the counterweight outward from geosynchronous orbit using a cable, the counterweight is forced to keep moving at geosynchronous velocity despite the fact that an object orbiting at that radius would be moving slower. The counterweight is thus moving too fast for its orbit and wants to fly away from Earth, but the cable that hangs downward prevents this. Bryan


 * Thanks, I think I got it (I was confused with the centripetal force but now it makes sense; ). This is a very interesting trick! also nice work on the failure points. Cheers -- Rotem Dan

Regarding cutting the space elevator at the anchor:

In Bradley Edwards' space elevator design, the ribbon is balanced so if it is cut at the anchor, it would not move. I found this quote from Newsweek: "What’s to keep the whole thing from flying out into space or crashing down to Earth? The upper half of the elevator gets thrown outward [by Earth’s rotation], and the bottom end is pulled down by gravity. Even if you cut it at the bottom, the ribbon would just float there." [http://www.msnbc.com/news/972957.asp?cp1=1 Going Up? - Newsweek] Astudent


 * That looks drastically oversimplified to me. If you have a space elevator that is exactly balanced, so that the weight of its lower portion is pulling downward with exactly the same force that the counterweight is pulling upward with, then as soon as you put any additional weight at all on the bottom end there will be more force downward than there is upward. The elevator will be pulled downward as a result. This would result in a catastrophic failure since moving the counterweight inward reduces the centripetal force, which accelerates the fall of the elevator. Without drastic measures such as cutting a large section of the lower end off to reduce the weight of the lower portion, the entire space elevator will fall down to Earth's surface. I suspect that Edwards is oversimplifying for MSNBC's benefit; he probably just means that if you cut the elevator it won't fall down to the ground. Bryan


 * Thanks for your reply. I was wrong earlier about the exactly balanced ribbon. Your explanation is very good. Astudent


 * No problem. Orbital dynamics aren't very intuitive even for conventional orbiting objects, let alone ones tied to the ground. :) Bryan


 * True, but we were only talking about cutting it. You wouldn't put a cargo going up on a cut cable, as that would cause the whole thing to fall.
 * Operationally, you'd need weights that you can move up and down on the out portion of the cable, so that you could lift cargo. You'd probably want some type of linear induction motor thingy, so you could just move weight up and down on that section, depending on whether you were lifting anything from earth's surface at that particular point in time.  You're probably always want it slightly imbalanced pulling against the earth's gravity (long-term loss to earth's rotation and other problems not-withstanding), or a very fast response system, so that someone coming up and yanking on the cable doesn't cause it to crash.
 * ~ender 2003-11-13 19:32:MST

This article says "geosynchronous" but "geostationery" is clearly what is meant
According to the article "Geosynchronous orbit" a sattellite with an orbital period equal to the rotation of the earth is geosynchronous. Only if it orbit is above the equator it's also geostationery. If its orbit is not above the equator it oscillates in the sky (I don't know if it moves in circles in the sky or if it only moves back and forth).

In this article about space elevators it is clear from the text geostationery is meant but I see most of the times geosynchronous. I don't know if the sources use the word geosynchronous or if the people that added the text accidentally used geosynchronous instead of geostationery.

If in one or more sources it is called mistakenly geosynchronous there, it should be mentioned in this article I think.

Anyway if I'm not mistaken geosynchronous should change to geostationery everywhere in this article. As I'm not sure how it's called in the sources I won't change it.

I'm really sorry I'm not in the mood to check all the sources. I hope someone else can do that. Laudaka 04:47, 15 Feb 2004 (UTC) (Paul/laudaka)


 * Actually, in both The Fountains of Paradise and Red Mars, the space elevator on Mars is designed to swing back and forth to avoid the moon of Mars (which is much closer than Earth's moon), so technically, it doesn't have to be geostationery. --ssd 05:52, 17 Mar 2004 (UTC)


 * Well, they were designed to shimmy out of the way of Phobos and Deimos, but they still run essentially straight out from Mars so they still count as geostationary (or to be really pedantic areostationary) -- wwoods 08:42, 17 Mar 2004 (UTC)

Hey, guess what, everyone? I just got this in the mail:

---

Subject: Re: Contact Form from LiftPort- The Space Elevator Company Date: Thu, 11 Mar 2004 10:02:36 -0800 sure, feel free to use our images. thanks for asking, a lot of people just "take" them. :-)

would you please post a link back to us?

when its up, please send me the link so i can look it over. thanks. and thanks for your interest in our project. take care. mjl

On 10 Mar, 2004, at 3:42 PM, Nobody wrote:

> The following was sent > On: 03/10/04 6:42 pm > > Name: Karen Pease > Email: daystar_setting@myself.com

> Comments: > I am interested in whether you would be willing to grant permission to > use one of your conceptual drawings or renderings in Wikipedia (a free > online user-created encyclopedia - http://www.wikipedia.org) as the > illustration for the encyclopedia entry for "Space elevator". > Naturally, the picture would be captioned as being an illustration > Liftport's design, which would get you a bit of free publicity. > > Just let me know - my email address is daystar_setting@myself.com.

> > > > Michael J. Laine President Chief Strategic Officer LiftPort Group "The Space Elevator Companies"

245 4th Street Suite 508 Bremerton WA 98337

360.377.0623 - vx 360.824.7394 - fx laine@liftport.com

www.liftport.com

---

I'll get a picture uploaded right away. Would we prefer a drawing or a rendering? I prefer the drawings, personally... Rei

has some images, and I think they're better than some of the ones currently in the article. Since it's a NASA publication, I assume these are public domain? Fredrik 19:05, 17 Mar 2004 (UTC)

Well, I'm not particularly impressed by the pictures in that publication, and the NASA proposals seem a lot less well thought through than the Liftport or HighLift proposal systems (for example, discussing climbing with electromagnetic propulsion without running the numbers, which work out to an incredibly unfeasable amount of extra bulk to the cable). Also, while NASA generally releases everything to the public domain, you still need to ask if it isn't specifically stated. Rei

I thought the state of matters is that *everything* NASA releases goes into the public domain. Fredrik 17:26, 19 Mar 2004 (UTC)


 * Most of NASA's work is in the public domain, but that doesn't *guarantee* that something that NASA has posted is in the public domain. You still need to ask permission or find somewhere in which the document is declared to be public domain.  For example, here on NASA's page about Project ASPEN, they specifically state that their information about it is not in the public domain .  You can't just assume.   Rei


 * "NASA artwork of the space elevator ... created by Pat Rawlings" is the attribution. That tells me that NASA owns it. The last page tells me that the publication may be distributed without limitation.  I can't find a specific statement that addresses the specific status with respect to the public domain.  Apparently public funds paid for it, if that figures into the discussion. - Bevo 18:13, 19 Mar 2004 (UTC)

History: Whose notes were sent behind the Iron Curtain?
In the first History paragraph, the last line says, "His notes were sent behind the Iron Curtain after his death." The context implies "he" is Nikola Tesla, who was a naturalized American citizen at the time of his death and had his papers seized by the FBI for national security reasons. I doubt they went behind the Iron Curtain. Was it instead Russian Konstantin Tsiolkovsky's papers that "were sent behind the Iron Curtain"? If so, it should say so explicitly. -- Jeff Q 05:59, 30 Apr 2004 (UTC)

Impossible
This is now a featured article. Of course it reads very well but the balance is poor - it is all very Popular Mechanics. It would serve Wikipedia well if it were more plain just how difficult a project this is. Cost is almost the least of the problems. Typically a solution to one problem makes another much worse. Paul Beardsell 09:34, 30 Apr 2004 (UTC)
 * I agree. My first thought when I saw this on the Main Page was, "Wha? Is this really worth a 'featured article' -- a hypothetical engineering problem?" Alcarillo 15:15, 30 Apr 2004 (UTC)
 * I have done a lot of work to remove the overly optimistic aspect from this article by adding in a lot of the potential pitfalls and pointing out out how far behind current materials tech is from what is needed for a space elevator. I'm surprised that people still view it as being so overly optimistic.  --Rei
 * I think it is great. Very interesting. Congratulations, guys! 198.54.202.2 17:22, 30 Apr 2004 (UTC)

Yes, it is a great article. But, face it, this will not be built ever^H^H^H^H in the next 50 years. It's more likely we blow ourselves up or die of the plague or get hit by a meteorite or the 2nd coming happens first. Well, nearly! That this is entirely speculative needs to be said. We'll have all the gadgets that the Jetsons had first! Paul Beardsell 21:17, 30 Apr 2004 (UTC) I hope the small edit I have done to the article is considered acceptable. Please, as always, revert if you like! Paul Beardsell 21:26, 30 Apr 2004 (UTC)


 * And that is your personal opinion. And many people at NASA disagree with you about whether it will eventually be built, or whether it is impossible.  50 years?  Probably not.  However, it is not entirely speculative - NASA, as well as many private organizations, have run many calculations and simulations on it.  I have even a cable tension calculator program (spelsim) on my computer right now.  It is possible, but will not occur until we can produce materials on the large scale that have tensile strengths that we currently only have on the nano-scale.  In short, you must argue that this is an impossible task.  If you think so: why?


 * The burden of showing that this is a practical idea is yours. Start by naming the people at NASA (you invoke them, not me) who think this is a practical idea.  Paul Beardsell 23:32, 30 Apr 2004 (UTC)


 * If you'll note, the article does include all of the potential pitfalls, and where the current level of technology stands on them. If you have any other potential pitfalls please add them; if not, don't complain. --Rei


 * I am not complaining. All I did was fix the incorrect impression that many/most/all optimists thought that construction was starting real soon now.  Do you think that?  Paul Beardsell 23:35, 30 Apr 2004 (UTC)

Regretfully (because it is a neat concept) cold fusion is a whole lot more likely. There isn't anything that NASA doesn't have a look at. In this case, to rule it out. Bending forces on the cable as the object is speeded up laterally as it travels up the wire, the mobile anchor to avoid storms,  the meteriotes,  the corrosion,  the dodgy economics (Heck, you cannot send 1KG that distance on the ground for that price!)  Allow us Wikipedians some dignity. It's only a tiny change I have done and I have now moderated that further. Don't be annoyed by me. I'm sorry if I am having a go at anybody's pet idea. 212.56.101.83 23:18, 30 Apr 2004 (UTC) I'm sorry I did not mean to be anonymous. That is me. It seems I am not alone and my change has been beefed up by others. Paul Beardsell 23:22, 30 Apr 2004 (UTC)

Economics questions

 * $3/kg it is claimed. How much does it cost to send 1 kg 38000km horizontally?  Why would it be cheaper to do this vertically?


 * Electricity will be sent up the cable for power. How much power loss is there over 38000km?  Or are we relying on superconductivity?

Paul Beardsell 23:56, 30 Apr 2004 (UTC)


 * When considering how much it costs to send stuff horizontally, bear in mind that to be an accurate comparison you'd have to assume that a perfectly straight and level railroad exists along that path with no adverse weather conditions and no traffic obstructions. The cheapness becomes a little more believable under those circumstances; how much does it cost to mail a 1kg postal package to the other side of the world and back with transportation systems far inferior to that? As for power transmission, a variety of techniques have been proposed in addition to running it up the cable; the elevator cars could carry their own self-contained power source, or (as depicted in the Liftport images currently used in this article) you could beam the power to the elevator with lasers or microwaves. It may also prove more economical to power the elevator system from the top, using a solar power satellite at the geosynchronous station. I don't have any numbers, but as far as I'm aware these matters are still somewhat up in the air depending on your technology assumptions. Bryan 01:23, 1 May 2004 (UTC)

Power source: Solar cells at the top is a possibility but there is still the problem of transmission losses. Containing a microwave or laser beam to a small enough diameter so as it can be picked up by a small enough collector not to be prohibitively heavy is impossible. Beaming that much energy through the atmosphere also has unacceptable power losses. So, it's self-powered cars? We put a jet engine turbine in the elevator car to generate the electricity. Or we direct the jet engine downwards to push it up. And where do we put the jet fuel and the oxygen for the jet engine? It's just a rocket on rails. I suggest we discard the rails. Paul Beardsell 11:41, 1 May 2004 (UTC)


 * It is in fact quite possible to contain a microwave or laser beam to a small enough diameter for a small collector on the elevator car; you need a larger emitter to focus that small, but since the emitter is on the ground (or geostationary orbit) you can make it as large as necessary. A high-frequency laser would be easier to focus than microwaves due to diffraction limits. As for onboard power sources, why do you suggest a jet engine (especially as a source of thrust rather than electricity)? One benefit of an elevator over a rocket is that you don't need a high thrust-to-weight ratio to launch; you can use low-power but highly efficient power sources instead. You could use a small nuclear reactor, for example, or fuel cells. Bryan 21:01, 1 May 2004 (UTC)


 * Lateral acceleration (to 3km/s) is more of a problem than hauling the thing up the cable. That cannot be done using a nuclear power source:  You need something pushing sideways.  Paul Beardsell 06:07, 2 May 2004 (UTC)


 * The angular momentum ultimately comes from Earth's rotation, which is infinitesimally slowed when a payload goes up the elevator and intinitesimally sped up when a payload descends. Bryan 06:16, 2 May 2004 (UTC)


 * The angular momentum of the whole system is preserved - there is no infinitesimal change to the whole system. Sure the earth itself has an immeasurable change in its angular velocity.  The angular momentum of each KG sent to geostationary orbit is increased dramatically.  That has to come from somewhere.  A lateral force is required on the mass.  Without it we will bend the cable and pull the station out of orbit.  Paul Beardsell 06:29, 2 May 2004 (UTC)


 * The amount of angular momentum gained by the payload moving outward on the cable is exactly the same as the amount of angular momentum lost by Earth. The payload is much, much lighter than Earth, so the same amount of momentum will produce a much, much greater change in velocity for the payload than it will for Earth. Bryan 06:43, 2 May 2004 (UTC)


 * Yes. But angular momentum must be transferred one to the other!  Newton II:  A change in velocity requires a force.  At geostationary orbit the speed is 3km/s.  At the equator the speed is 1 km/s.  The force is to speed up the object, the reactive force (Newton III) slows down the earth.  Momentum is preserved but work is done!  Paul Beardsell 06:58, 2 May 2004 (UTC)


 * Yes, this force is provided by the tension in the cable. Bryan 07:06, 2 May 2004 (UTC)


 * Tension is along the cable. We need a force perpendicular to it.  Paul Beardsell 07:45, 2 May 2004 (UTC)


 * The cable tilts slightly when payloads move along it, as I described below. This gives an eastward or westward component to the cable's pull. Bryan 07:54, 2 May 2004 (UTC)

Cost: I think that the $3/kg figure is the marginal cost i.e. the cost of lifting 1 more kilogram. It neglects the cost of capital. Paul Beardsell 11:41, 1 May 2004 (UTC)


 * I removed this:


 * Of course, if we assume the same lossless conversion of energy, rockets can deliver payloads for a comparable cost. The use of rockets avoids having to solve the major engineering problems associated with a space elevator. And we can start now without the massive capital outlay. Oh, assuming the same lossless conversion of energy that the economics of the space elevator depends on, of course.


 * Reasons:


 * It's written in an informal style
 * The way it's worded, it promotes rather than presents this point of view
 * I would like to see some evidence that lossless energy conversion in rockets could be achieved at all and without major, costly engineering and research difficulties


 * I don't mean to be rude here, and I agree that all aspects of the issues involved must be presented. This particular part isn't substantial in its presentation, however. Perhaps the best solution would be to restructure the whole economics section. Fredrik 13:54, 1 May 2004 (UTC)

OK, I agree with your 1st two reasons BUT the whole article is written in a space elevator promoting fashion. Let's be clear about this: This is an interesting but UNIMPLEMENTABLE idea. Essentially we would be better poking fun, than cosying up to those crank consultancies trying to siphon off their own 1% of NASA's huge budget. Paul Beardsell 15:21, 1 May 2004 (UTC)

As for the third reason: It is the space elevator article which wants to assume lossless energy conversion for itself. I simply would like the same privelege for rockets. Paul Beardsell 15:21, 1 May 2004 (UTC)


 * Advanced versions of the space elevator can recycle the energy of downward traffic to lift upward traffic. Rockets have no such potential. Talk of lossless conversion simply sets the lower bound on the cost; nobody thinks that could be reached in practice. --wwoods 16:43, 1 May 2004 (UTC)

Untethered Space Elevators
I read on the Internet a while back of a proposal for an untethered elevator. The bottom of the elevator would be in low earth orbit, above wind and lightning. But I can't find my source now. If anyone knows more perhaps they could write something.

Zeimusu 12:20, 2004 May 1 (UTC)

It does not work: The lower orbit has a shorter period than the upper. The lower station races ahead of the upper. They rotate about each other making the whole assembly useless. Paul Beardsell 13:57, 1 May 2004 (UTC)


 * Not so. There are proposed tether systems which rotate, and others which don't. See tether propulsion for some info. Being much shorter than the space elevator, they are much more likely to be built. --wwoods 16:43, 1 May 2004 (UTC)


 * I don't know which proposal in particular Zeimusu is talking about, but he may simply be talking about a space elevator that doesn't quite reach the ground. The lower end would be reached instead by a suborbital spacecraft, or if it's low enough perhaps a high-flying aircraft, either of which would be much cheaper than a spacecraft that had to attain orbit on its own. Bryan 20:45, 1 May 2004 (UTC)


 * A low earth orbit space elevator is discussed in this conference publication from the external links section. Fredrik 20:58, 1 May 2004 (UTC)

Of course, it is possible to arrange that, for a short while, the lower station and the upper station are positioned one above the other on a radius to the centre of the earth but this is a dynamic equilibrium, not a stable one. As with any dynamic equilibrium the one above the other positioning on a radius to the centre of the earth would require active management. With computers and small impulse engines this can be managed UNTIL...

...we send something up (or down) the elevator. Then the mass of the elevator (which will be many 100's of tonnes) does not only have to be lifted against gravity (a problem which no one here is ignoring) but also (de-)accelerated to the same velocity as that of the other station. This requires lateral forces which could be provided by a rocket engine but that will require fuel and oxygen to be carried on board the elevator (hence the 100's of tonnes - the same amount of fuel as a rocket not on rails would require). The lateral forces cannot be supplied by an on-board nuclear reactor - all that can do us pull the elevator along the cable. This lateral acceleration problem does not only apply fatally to the untethered version of the space elevator BUT...

...also to the tethered version. Any mass taken to the geostationary position needs to be accelerated to the same lateral velocity as the station. This cannot be easily balanced by a descending mass (the cable being pushed sideways in one direction by the descending and in the other by the ascending elevator) because the cable is comparitively very, very thin in comparison to its length and each elevator car will be at a different position on the cable. The cable will be pushed sideways one way and the other. It will bow and snake and pull the station out of its orbit.

Paul Beardsell 05:58, 2 May 2004 (UTC)


 * In the case of an untethered elevator, yes, it would need to be dynamically rebalanced and the momentum restored. This could be done by high-efficiency thrusters such as ion drives, though, so there's still some benefit there over conventional rockets (hypersonic skyhooks have similar station-keeping requirements). As for the tethered version, the tower would be kept in tension by having its center of mass slightly beyond geostationary orbit. This means it's stable against minor perturbations and the angular momentum can be taken directly from Earth's rotation. No problem there, this is a basic issue that I'm sure pretty much every space elevator study would check before going on to other details. Bryan 06:13, 2 May 2004 (UTC)


 * OK. I have removed some stuff here I got wrong.  It's in the log if you're interested.  Paul Beardsell 08:09, 2 May 2004 (UTC)


 * It happens to the best of us, and if nothing else it lets us know what sorts of misunderstandings may need to be addressed in the article itself. It's too late at night for me to do it now, but tomorrow I'm going to go through the article and see if any of the explanations I used here in talk: need to be inserted there. Bryan 09:11, 2 May 2004 (UTC)


 * I think you need to do some more basic learning at this point. Ion drives do exist, and indeed have been used in various space missions - Deep Space 1, most famously. Ion drives cannot launch things into space, however, as they don't have sufficient thrust; they're only useful once they've been launched by other means. The cable doesn't need to be rigid to transfer angular momentum to and from Earth; when a payload goes up or down it the elevator tilts very slightly to the east or west, and as a result the tension gains a tangental component that pulls Earth's surface in that direction until everything balances out again. This doesn't apply to untethered elevators because they aren't connected to the ground. Bryan 07:06, 2 May 2004 (UTC)


 * Wrong way around, if the center of mass is beyond geostationary then it will be moving too fast to be orbiting there. It will want to move outward. Bryan 06:43, 2 May 2004 (UTC)


 * The further away the slower the angular velocity of the orbit. But if you were right then the result would be the same:  Your second favorite holiday destination would be decimated by a lump of useless scrap complete with ion drives.  Paul Beardsell 06:52, 2 May 2004 (UTC)  OK, I'm wrong here too.


 * You seem to have a very basic misunderstanding of how orbits work, here. The elevator is moving too fast for its orbit, so it will be thrown outward. Since it's tethered to the ground, this provides tension in the cable. It's just like twirling a weight attached to a string. Bryan 07:06, 2 May 2004 (UTC)


 * I was (wrongly) referring to the natural, untethered speed of a satellite at that altitude. Paul Beardsell 08:05, 2 May 2004 (UTC)

Avoiding other satellites
That other low earth satellites' orbits will have to be adjusted from time to time so that they do not collide with the cable is discussed in the article. That the same techniques will be used to adjust the orbits of some asteroids is also presumed. But now we have a cable which is being bent side to side by the ascending/descending cars to provide the force to accelerate/decelerate them as they move to/from the geostationary position. Over 38000km I reckon the cable will be deflected by 100m at least - possibly a lot more. How will this all be taken into account when deciding which satellite orbits need adjusting. No longer do we have to worry about a swathe being cut through the sky which is 2m wide but one which is 200m wide. What if there is a glitch of some description and a car is stopped for a few minutes? The deflected cable will swish gently from side to side over 200m. This will be unexpected! What about all those satellites we nudged? Paul Beardsell 19:02, 4 May 2004 (UTC)


 * A reasonably broad margin of error will be called for, I imagine. Arrange it so that no satellite comes within a kilometer of the predicted position of the elevator, and then you're fairly safe against both unexpected swaying of the elevator and unexpected course deviations by the satellite (within that margin, that is). Air traffic control does this sort of thing all the time; nobody would normally plan a trajectory that only barely misses some obstacle, they'll always try to leave room to be on the safe side. Bryan 01:10, 5 May 2004 (UTC)

Article moderation required
Bryan, first I ought to thank you for taking so much time to explain things to me. I apologise that on one or two occasions some explanations may not have been necessary if I had read the article more carefully. However this is not true for many of the points I have raised: The answers may be obvious to you but not to many otherwise scientifically literate readers of the article. When I make an ill-informed observation this is an opportunity to improve the article. When I make a good observation, likewise.

In my view (but I would say that wouldn't I) the bias is the other way. There seems to be a tendency here to sweep problems under the carpet. Supporters of the concept refrain from criticising points made by other supporters that they disagree with. In the article itself and here on the talk page the choice is presented as if it were uncontroversial: For reasons of the weather either the base must be movable or it must be untethered. Avoiding satellites make the movable base problematic so now it is no longer required.

It seems to me supporters of the concept seem to me to feel free to swap from one set of mutually exclusive proposals to another as they seem fit. This might not be true for any one individual but as a group you are remarkably uncritical of one another. I know there is no group per se!

This is a highly speculative proposal that should be presented in an encyclopedia as such. An introductory sentence does not compensate for the overall tone. This otherwise excellent and highly interesting article needs to be moderated.

Paul Beardsell 12:11, 5 May 2004 (UTC)


 * But this is simply not true. There's no good reason to move the base or leave it untethered, so the tradeoff that you claim is required simply doesn't exist. Look, I have no problem at all with putting cons in this article as well as pros. I practically wrote the entire "failure modes" section of the article when someone mentioned here that there wasn't anything in here discussing problems the system had. But if you want to talk intelligibly about the problems a space elevator might have then you have to have at least some basic knowledge about how the idea works. Your questions have been useful, they've resulted in some new material being added to the article in answer to them, but your constant harangueing about how we're all being foolish by overlooking "obvious" flaws and that the concept won't work for nonsensical reasons is making me feel quite frustrated and adversarial. If you don't know how this concept works, ask questions to learn about it instead of starting out by trying to lecture people on how you imagine it works. Then perhaps you'll be able to come up with some objections that can't be dismissed by anyone who knows a bit about this stuff out of hand. Bryan 15:32, 5 May 2004 (UTC)

If there is no need for a movable base station why do you not say this in the article? (The article is uncritical of this proposition.) Do not tell only me! As you said, you wrote the failure modes section. The economics section which was wildly optomistic and certainly not NPOV has been helpfully rewritten by another editor and this has been at least partly provoked by me. There was room for improvement and, I think, there still is. I think you respond to my confrontational style, not really to the substance of my points: With one exception (my originally flippant paragraph in the economics section) my wrong/lecturing/nonsensical/haranguing (select any of your epithets) contributions have been confined to here, to the Talk page. To educate myself about space elevators I could consult an encyclopedia: Wikipedia fell open at this article one day and I was entertained by the article but some of my questions were not answered by it, some facts seemed wrong (they might have been right but not obviously so to the scientifically literate albeit elevator-ignorant reader) and some "facts" were wrong. You put me in a catch 22 situation. But I acknowledge my style may not have helped. Paul Beardsell 16:27, 5 May 2004 (UTC)


 * I do thank you for confining this argument to talk:, if it had been taking place in the article itself I would have lost my temper long ago. Even as it is I've let my frustration get to me more than I should, sorry about that. Perhaps you could try making a list of the details that you feel the article still doesn't go into enough detail about, and we could go from there? Bryan 01:52, 6 May 2004 (UTC)

Take a break
For God's sake, Psb, every single time I try to reply to a comment, I get an edit conflict and you've already posted half a dozen more. I can't take this. Instead of asking us questions, go read a report on the physics and economics involved instead of harassing us here. I'm out of here until you calm down. Rei 18:03, 6 May 2004 (UTC)

You invoke your supernatural being, I'll invoke mine. Just have a look at the log.


 * 1) (cur) (last)  . . 19:13, 6 May 2004 . . Psb777 (=Take a break =)
 * 2) (cur) (last) . . 19:08, 6 May 2004 . . Psb777 (=Cost per kilogram= shout me down, why don't you)
 * 3) (cur) (last) . . 19:03, 6 May 2004 . . Rei (Take a break, Psb!)
 * 4) (cur) (last) . . 19:01, 6 May 2004 . . Rei
 * 5) (cur) (last) . . 18:58, 6 May 2004 . . Psb777 (=Economics questions= lossless misleading)
 * 6) (cur) (last) . . 18:49, 6 May 2004 . . Rei (=Cost per kilogram=)
 * 7) (cur) (last) . . 18:28, 6 May 2004 . . Psb777 (=Economics questions= Lighten up, Rei.)
 * 8) (cur) (last) . . 18:09, 6 May 2004 . . Rei (=Economics questions=)
 * 9) (cur) (last) . . m 15:51, 6 May 2004 . . Psb777 (=Economics questions=)

You exagerate just a little. Multiply by 0.5%, why don't you. My edits have also been plagued by conflicts. I'm glad you're taking a break. Paul Beardsell 18:13, 6 May 2004 (UTC)


 * I'll step back in just quickly to correct Psb's "truncation":

(cur) (last). . 18:16, 6 May 2004. . Psb777 (=Take a break=) (cur) (last). . 18:13, 6 May 2004. . Psb777 (=Take a break =) (cur) (last). . 18:08, 6 May 2004. . Psb777 (=Cost per kilogram= shout me down, why don't you) (cur) (last). . 18:03, 6 May 2004. . Rei (Take a break, Psb!) (cur) (last). . 18:01, 6 May 2004. . Rei (cur) (last). . 17:58, 6 May 2004. . Psb777 (=Economics questions= lossless misleading) (cur) (last). . 17:49, 6 May 2004. . Rei (=Cost per kilogram=) (cur) (last). . 17:28, 6 May 2004. . Psb777 (=Economics questions= Lighten up, Rei.) (cur) (last). . 17:09, 6 May 2004. . Rei (=Economics questions=) (cur) (last). . m 14:51, 6 May 2004. . Psb777 (=Economics questions=) (cur) (last). . 14:43, 6 May 2004. . Psb777 (=Economics questions= regeneration hampered by transmission losses?) (cur) (last). . 02:02, 6 May 2004. . Psb777 (=Avoiding other satellites= dodgems) (cur) (last). . 01:52, 6 May 2004. . Bryan Derksen (cur) (last). . m 00:23, 6 May 2004. . Psb777 (=Cost per kilogram= fmt) (cur) (last). . 00:04, 6 May 2004. . Psb777 (=Cost per kilogram= rocket launch cost per kg payload) (cur) (last). . 23:40, 5 May 2004. . Psb777 (=Cost per kilogram= cost of propellent) (cur) (last). . 18:13, 5 May 2004. . Psb777 (=Cost per kilogram= cut'n'paste) (cur) (last). . 17:40, 5 May 2004. . Rei (cur) (last). . 17:30, 5 May 2004. . Rei (Geez, Psb, give me a chance to respond.) (cur) (last). . 17:19, 5 May 2004. . Psb777 (=Cost per kilogram=) (cur) (last). . 17:18, 5 May 2004. . Psb777 (=Cost per kilogram= invitation to explain reversion) (cur) (last). . 17:16, 5 May 2004. . Psb777 (==cost per kg==) (cur) (last). . m 17:08, 5 May 2004. . Psb777 (=Economics questions= clarity) (cur) (last). . 16:57, 5 May 2004. . Psb777 (=Economics questions= please look at kid with marbles homework) (cur) (last). . 16:47, 5 May 2004. . Psb777 (=Economics questions= kid with marbles doesn't know his acronyms) (cur) (last). . 16:44, 5 May 2004. . Psb777 (=Economics questions= kid with marbles responds) (cur) (last). . m 16:30, 5 May 2004. . Psb777 (=Article moderation required=) (cur) (last). . 16:27, 5 May 2004. . Psb777 (=Article moderation required= style vs substance)


 * And that's only for the talk page. Psb, can you not understand why people get sick of someone who hasn't even read a paper on the subject trying to take over an article?  Rei 19:14, 6 May 2004 (UTC)

I quoted from the log to show that over the period that Rei was saying he was experiencing edit conflicts that he was making as many edits as me. It is true that I made numerous small edits earlier but that is just not relevent. Rei wasn't here then. Paul Beardsell 22:42, 6 May 2004 (UTC)

This page is getting awfully big; anyone object to removing discussions which are no longer active? --wwoods 18:14, 7 May 2004 (UTC)

Please, go ahead, hide as many of my earlier misconceptions as you can manage. Paul Beardsell 18:25, 7 May 2004 (UTC)


 * Go ahead. :)  Rei 19:11, 7 May 2004 (UTC)