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Space

Riding The Space Elevator 319

Posted by Hemos from the where's-willy-wonka dept.
savas was one of the folks who sent in the story concerning the possiblities of a space elevator in 50 years time. They make good sense, especially if we are committed to doing something more than the current small commitment to space.
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Riding The Space Elevator More

Riding The Space Elevator

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  • Big, incredibly expensive global projects are usually funded more by American money than anyone else's.

    Like, say, the United Nations?
  • Wouldn't friction from the earth's atmosphere create a huge amount of heat, akin to what hapens the the space shuttle upon re-entry, on the cable?

    Naw. From the point of view of the earth, it's a very tall mountain. Mountains on earth don't get hot from air friction. Airplanes travel faster through the air than the cable would.

    Also, don't think of this as a wire. It would probably be 100+ ft around at the earth's surface.


    ...phil

  • You've got the wrong picture. This isn't attached to the surface of the earth. Think of it as a very long skinny satellite, in geosynchronous orbit.


    ...phil
  • Sure. Ignoring the fact that, in the present, things like this get funded by American dollars. In 50 years, maybe not.

    And now I sit back and watch my karma die.

  • You build it by starting with a space station in geosynchronous orbit over the equator and extending it both down and up simultaneously (to keep the center of gravity in geosync orbig).


    ...phil
  • And oscillate back and forth with gravity until 'caught' (something along the lines of a large net) .. yea.. could be fun.. what if you're never caught though? :)
    --
  • I am scared of heights. The State of Liberty was tall enough for me to get dizzy. I don't have any idea what would happen if I had to travel miles into space...
  • Yes, I've read Red, but not Green or Blue (yet anyway). A space elevator would make a prime target for terrorism. In reality, terrorist would probably attack the base (as apposed to the counterbalance asteroid), so the cable would drift away, instead of coming crashing down in a huge mess.
  • That would mean patents on the wheel, lever, ramp, etc. are all open and waiting to be exploited.

    Jeff Bezos call your office!

    DB
  • And IF you reached the other end gravity would suck you back down into the hole.

    You've just designed a perpetual motion machine, but you'll have to build a working prototype before you can patent it. :)

    DeanT

  • It's impossible.

    How many things in the world once thought to be impossiable are very possiable today?

    Was it impossiable to think 50 years ago everyone could have a computer on thier desks?

    Was it impossiable to have a network to connect everyone to everyone else linked by light?

    Was it impossiable to think man would walk on the moon?

    Was it impossiable understand the atom?

    Was it impossiable to build a pymind of limestone in the middle of a desert?

    Was it impossiable to drag huge stones to a field inright them, and build a circle?

    Was it impossiable for the king and queen to lose all meaningful power in europe?

    ...and the list goes on...

    There is so many thing that was once thought impossiable that are very possiable today. Everything you state here can be changed or invented in the next 50 years. Look how far we have come in the last 100 years. Lights, cars, airplanes, computer, nukes, radio, the internet, lasers and so many other things.

    Anything with a people with enough will power behind it, is possible.

    MarNuke

  • babelfishes, that is...

  • I love the idea of taking an elevator to space, and I don't doubt that we'll eventually be able to build one (whether it will ever actually happen is another matter).

    However, one of the first concerns I had about such a tower, was how to protect it -- not only from accidental collisions with space junk or an errant airliner, but how about a dedicated terrorist with a bunch of missiles?

    The Elevator would definitely be a tantalizing target.

  • Not true, you'd still be in freefall. Do you think satellites in GEO experience gravity? If so, why don't they fall?

    Satellites are falling, which is precisely why they a person on one wouldn't percieve any gravity.
    The same thing would occur (briefly) if you were in an normal elevator that was falling down its shaft.

  • My thoughts exactly. If we can build something like a space tether, I imagine we can just build a sea-floor tether, and slap a platform somewhere above sea level.

    Look ma, internationwal waters. The biggest navy owns me.
  • I see this article suggests Carbon Nanotubes would be a good material to use. Only the findings reported in the heatsink article [slashdot.org] contradict this. This is the scientific equivalent of vapourware. Some scientists churn out this kind of story for ever: "We can achieve A using B assuming B has property C, only we don't understand B yet, C is a theoretical phenomenon that has never been observed and we haven't bothered finding out if A is really relevant to anything".
  • Even better, ship him off for project building in Iraq...

    B-)

    DB
  • I mean seriously. The risks involved in having something sticking out that far that is in orbit is just outragious.

    Name 'em.

    Why hasn't anyone done a "MoonBase"? ... A MoonBase would be a lot easier to build and maintain.. wouldn't it?

    Maybe. Moon bases are certainly in the 'talking-about' stage. The trick is, of course, getting enough to the moon to be self-sustaining.

    Everyone keeps trying to do these space stations that keep failing and falling apart.

    Uh, exactly HOW MANY space station has there been? I count one. The International Space Station is not yet commissioned, so the only example I can think of is Mir. To ask why it's falling apart, you only have to look at the government that's running it. One example does not make a trend.


    ...phil

  • In a world that loses its collective mind every time a hundred pounds of satellite debris comes down, do you really think anyone is going to be allowed to build a structure that could drop thousands of tons of material across a large swath of the planet if it failed (or the installation went badly)? One doesn't even have to be one of the neo-Luddites to see that maybe this isn't such a great idea, however cool it might sound. By the way, this idea is also known as a "beanstalk" (for obvious reasons), and Analog Science Fiction had a fascinating article some years back on how one might build and install one of these things.
  • Nope. You'd probably have atmosphere inside the hole. Friction would slow you down, and eventually you'd come to a rest at the earth's center of gravity.

    This is, of course, assuming that the actual act of falling is safe. I don't know enough about things like terminal velocity to know if you run the risk of dying of asphyxiation or burning up as you fall.

  • Ok, lets say that all the obsticles of structral materials, orbital harmonics, etc. etc. can be overcome, and we build this thing. Now, as I understand it, the bottom end is attached to something at this end... in this case, a 50 Km tall building. This is, of necessity, located on Earth's equater. But don't we have plate tectonics? Will it STAY on the equater? Or will we have to relocate the anchor point ever few hundred years?

  • It is held up by sky hooks.
  • 1. The tether NASA melted was trying to be both structural and current-carrying. THAT is why it melted. CNTs (depending on how you shape them) have an electrical conductivity somewhere between that of graphite and that of diamond (moderate to nil).

    2. The tether could most certainly be rigid - it's a straight line connecting GEO and the surface of the Earth. Tidal forces (from the moon and the sun) _may_ induce some sway - but this can most certainly be dealt with by appropriate movement of the balance mass beyond GEO.

    3. Not according to my freshman engineering statics class - don't think of it as a large tower, think of it as a very large, flat bridge.

    4. You put it in any equatorial country - I prefer South America, because of the Andes, but Africa would do fine. The tether goes straight up, so as long as it isn't within 10km of a border on the ground, nobody can do anything about it.

    So, it isn't impossible at all to imagine. I personally think we won't, but not because we can't. The possibility of it crashing to Earth (and thus making a hundreds-of-kilometers-long crater) will guarantee that permits will be very hard to get.

    Now, constructing such a tether (I prefer the term 'beanstalk' myself) on Mars would be more feasible - the Martian gravity, being lighter, gives us the advantage of being able to use contemporary materials. The CNTs discussed in the article have incredible tensile strengths, but only in lengths of less than a meter, currently. Additionally, Phobos and Deimos, if moved to Mars synchronous orbit (Mars GEO), would provide an ideal source of materials and a base for construction.

    Even considering the above, however, it is unlikely that a beanstalk will be built on Earth. Besides the difficulty in making one in our 9.8m/s^2 gravity, beanstalks are also confined to a two-dimensional plane, because of the need to connect to a point on the equator.

    I'd refer you to a webpage with more specifics, but it isn't done yet.

    Howard Swan (fenris@nmt.edu)

    Earth is the cradle of humanity, but one cannot stay in the cradle forever. -Konstantin Tsiolkovskii

  • Oh well I have no clue what the hell I'd make it out of

    Metal whisker fibers and carbon nanotubes both have the required tensile strength, and have both been produced in the laboratory. It is not a question of the materials existing. It is a question of being able to easily and cheaply produce them in bulk.

    Nanotubes were mentioned in the article. Please read it thoroughly, as it may answer other questions you may have. It also cites more technical articles, if you want more detailed information.

  • Uh, exactly HOW MANY space station has there been? I count one.

    Two, I believe, if you count Skylab. You may not be old enough to remember it very well; I was in high school then.

  • Re:My thoughts... (Score:3)

    by Azog ( 20907 ) on Friday September 08, 2000 @06:56AM (#794732) Homepage
    Lets have some common sense here. . . . . I'm not even going to waste my time looking up facts to call this ridiculous, because its common sense.
    (sigh). Yeah, good idea, don't even bother looking up facts. Who needs facts when you have common sense! Just ignore the fact it's NASA's research, and call it pop-sci. Just ignore the fact that smarter people than you have done research on this, and have done lots of math, because common sense says they must be wrong! Ignore the facts in the article about the tensile strength of carbon nanotubes, because common sense says if you can't imagine it, it must be impossible.

    And it's common sense that quantum physics must be wrong, cause it just doesn't make sense that something could be like a wave or a particle at the same time!

    And it's just common sense that no one will ever be able to make a fabric that could stop a bullet.

    Oh wait, they did - it's called kevlar. Hey! that's your alias!


    Torrey Hoffman (Azog)

  • a structure that could drop thousands of tons of material across a large swath of the planet if it failed

    Do you realize that the description you've just given also applies to Hoover Dam? The only distinction is how rapidly the material gets (re)distributed.

    I think within 50 years we'll get to where we can trust macroengineering if materials science gives us a reason to.

  • Everybody talks about building this kind of thing, but nobody talks about what it might take to MANTAIN it.

    Structures of any type do not survive any signifigant length of time without maintenance. Large projects in particular often require more resources in maintanence than in construction, and if the construction takes any length of time at all, then maintenance costs start on the parts of the structure that are complete.

    Worse yet, this would be a structure that you would have to maintain. Consider what would happen if this puppy precessed a little and fell over (excuse me, deorbited...) I wouldn't want to be anywhere near it, and in this case "near" is a pretty big place.

  • Re:Where will they put it? (Score:2)

    by Anonymous Coward
    Venezuela...
    Well, around here things are not going very well. We have a stupid president who is more interested in appearing on TV than governing. He tries to get the masses to rebel. (against what? who knows). He changed the constitution to whatever he wanted (well, it's a little more complicated, but that's the bottom line). His economic plans are laughable to nonexistent. All international investors are avoiding us like the plague. All Venezuelans who have the money are fleeing the country. Unemployment rates are the highest it's been in the history.

    Oh, and he was just reelected for 7 more years (I am not going to express my opinion on whether he cheated or not).

    With all that said, yes, Venezuela would be a good place. Set up in the Bolivar state, (Yes, near rain forests and national parks, sorry). You'd be on the guayana shield (Basically a REALLY big rock) so there are no earthquakes. You'd be very close to many different rivers which are being or will be exploited for hidroelectirc power. Iron and aluminum industries are in the area, plus the biggest oil exporter outside the middle east is (take a guess....) Venezuela. (there is also diamond, gold and I think a little bit of radiactive materials, I'm not sure if it'd help)

    You have sea/river transportation as far as Puerto Ordaz, a few hours away, and if you are going to build a space elevator, you might as well build a nice highway from it to Puerto Ordaz.

    Yes, Venezuela is having problems. Hopefully Chavez will be overthrown soon :-). But having the influx of money and jobs would be nice. Plus I'd bet it would be cheap labor for you guys :-)

    (And thanks for the technologically clueful vote :-). Yes, there are some of us left. It's just hard to find a job with all the companies closing down)
  • A tower attached to a cable that ascends into the heavens. This is by no means a "NEW" idea.

    It's great that my grandchildren may actually see it happen, but it's not new.

    LK
  • Mod that up as funny.

    --
  • If you look at the map in that article, the only part of the Philippines that comes close to the equator is the southernmost islands, mainly the island of Mindanao, which is something like 95% Moslem and gives the Philippine government as much trouble as Quebec citizens give Canada (demands for autonomy and all that kind of stuff). The Philippines gets hit with typhoons each year, floods from those typhoons (and rainy seaon in general), earthquakes and two active volcanoes (Mayon and Pinatubo), not to mention the possibility of tidal waves from earthquakes in other places. So generally speaking, the Philippines would be a bad place to locate the elevator.

    As far as the Stephenson comparison between the Philippines and America, I haven't read the book but the comment sounds true. The Philippines was a US colony for about 50 years and up to a few years ago was the one of the most pro-US countries in the world. Then around 1992 they traded in their two US bases (Navy: Subic, Air Force: Clark) for a handful of nationalism. Most Filipinos emulate Americans and want to be like them or look like them or move to the US or all of the above.

    Anyway, I digress. Short summary: 1. No, you don't want to build the tether there; 2. The Cyrptonimicon comment is on the money. (In this case, a peso. ;-)
    --

  • Don't anchor it (Score:4)

    by K-Man ( 4117 ) on Friday September 08, 2000 @09:02AM (#794759)
    The thing would fly perfectly well without an anchor; it's just a matter of putting it in a stable orbit with one end of the cable near the surface. It could be kept out of the lower atmosphere, and if needed a small difference from geosynchronous orbit would allow it to circle the equator slowly. One could also put aerodynamic forces to good use in adjusting the thing down or up.

    Anchoring it to the earth would only be necessary if more downward force is needed, but it seems to me that down-force is to be avoided. Keeping the thing up with minimal additional tension in the cable would be better.

    One should also look at what happens if the cable breaks. The greater the tension, the greater the energy released, and the larger the perturbation on the circular orbit. If the thing can be kept up without a lot of external force (i.e. yanking on the string), it's probably more stable.
  • I certainly did remember and consider Skylab (I was getting out of college at the time), but discounted it. It was never meant to be a true space station.


    ...phil
  • From the following reasoning:

    • The Mesopotamians knew that, no matter what you did, you could never destroy anything. (Burning something leaves ash & smoke, for example.) They also knew that some things change, with time, such as seeds, leaves, ores->metals, etc. These same observations led the Greeks to conclude that the world was made up of "atoms", which could be combined into certain elemental substances. Given that the Mesopotamians had much the same attitude to learning as the Greeks, it would not be at all implausable that they reached the same conclusion.
    • That, alone, is not enough. However, they DID have some things which would have nailed it. They had simple acid batteries. Useless, as they had no technology advanced enough to use electricity, these would still have forced the Mesopotamians to reach the conclusion that something flowed out of the battery jars, through certain substances, and back into the jars.
    • So, we now have a theory of elements and atoms, and of current. Is this enough? Maybe. No known "element" or "atom" had the property of current, so they would either have been forced to add one specially for it, or conclude that atoms could be "fixed" or "flowing". To all intents and purposes, "flowing" would be the same as being charged.
  • Please, bring up some more irrelevent arguments for this article. Here's a thought: I'm going to make this super strong material that'll let me build a space elevator that'll let people get there on $222 each way! Oh well I have no clue what the hell I'd make it out of, and I have no clue how much it'd truely cost, but if it cost X, and you split it up by Y, etc. etc.
    Give me some facts. Research it. Show the material. Do some tests. Put up some data. None of this assumption crap. The Scientific Method is what defines science and helps us describe our environment. I see no evidence of that here. Just a bunch of assumptions and "cool shit". What I'd love to know the most is: How the hell do they go about constructing this? Obviously from the top down. How many rockets does it take to put this amount of crap in space? How the hell do they expect to get an asteroid... thats a big deal... How do they expect to build it? People, machines? etc. etc. etc.

    Its a long into space; not nearly as far as your brain however... its out there somewhere.

  • Brazil has a space industry already. (Score:5)

    by DHartung ( 13689 ) on Friday September 08, 2000 @09:25AM (#794782) Homepage
    Hairy Potter, woefully clueless American, wrote:
    Looking at the equatorial slice, you have Central and the northern part of South America. That's close to the US, but the only country in that area that sounds somewhat reasaonable is Venezuela. I think they're stable, and at least somewhat technically clueful.

    Hairy, you may want to read the newspapers once in a freaking while.

    First of all, you're completely wrong about South America, which has come a long way in the last twenty years. Not only have most countries turned from military dictatorships or nationalistic juntas toward multiparty democracies, most are fully industrialized and modern. Brazil even has its own nascent space industry with a launch site at Alcantara [spaceviews.com], and an aeronautical industrial center calling itself Space Valley [accorbrasil.com.br].

    Brazil has skyscrapers, subways, and even computers. (What, did you think they lived in mud huts?!)

    Venezuela, on the other hand, has recently turned into as close to a rogue state as you can get and not actually be one. The President has endured the censure of the United Nations, the Organziation of American States, and others, and has deliberately met with pariah leaders like Moammar Khadafy and Saddam Hussein. Venezuela is heavily Western-invested due to its oil industry, but many companies are reconsidering its long-term political stability.

    A shame there aren't more, as close to the US is a major plus, since American will probablly pay for most of it.

    Why would you assume that Americans will pay for most of it? Why would you assume that taxpayers will pay for most of it? More likely it will be built by an international consortium supported by investors and ultimately funded by the companies that buy its services. (Look at the Chunnel, or any modern major toll bridge, for examples.) Of course, that's assuming that stick-in-the-mud American industry is interested, which they may not be. (Our economy goes through phases during which it will throw money any and all innovation, no matter how inane, and during which the very word innovation is considered poison. Look at high-tech from 1999 to 2000 for an example.)

    Going East, we get to Africa. Enough said there, I wouldn't invest a significant amount in Africa until it gets more stable.

    Africa's a pretty big place, kiddo. Some parts are stable, others are not. That said, the industrialization there in 2000 isn't that convenient for a space industry. That could change, though.

    Further East is India and Sri Lanka. India would certainly be a possibility, they have high tech, they speak English.

    What kind of incompetent school did you go to, that you believe speaking English is a pre-requisite for mastering high technology? India is not only a land of breathtaking scenery mixed with breathtaking poverty, it is also a land that has made a leap to the cutting edge of high technology. The computer industry is supplied by a steady stream of incredibly smart and motivated people from India, many of which I've been proud to work with.

    While Singapore has a harsh dictatorship, it is stable and high tech. Indonesia and the Phillipines have too many trouble.

    Singapore's Asian-style strongman semi-democracy isn't what I would call open and free, but I wouldn't call it a dictatorship either.

    Basically, I think you have a view of the world that is informed mainly by 30-second sound bites on CNN Headline News. Get out of the house once in a while. Talk to people who look different from you. Read a book or a newspaper. The rest of the world is a little more interesting and capable than you think -- and not all decisions about the future are made in the United States.

    Good grief.
    ----
  • Note that the basic physics requires the center-of-mass point to be in geostationary orbit; that requires a huge mass to be tied down to the other end. The article suggests an asteroid. People have often mentioned moving asteroids into Earth orbit for mining purposes, but that is just incredibly unlikely, not from a technical perspective (where we can always speculate on future technologies) but rather from a political one. Just imagine the public backlash if one suggested to move a few-km sized rock, capable of a 100 hydrogen bomb explosion, and able to wipe out most of life on Earth. Sure, you may have the technology, but one minor slip-up...

    Given our previous experience with small missions (think Challenger, Galileo, Mars missions...), there is a significant probably of disaster...

    There are ways around this; the most obvious being importing lunar regolith for both the elevator and the counterweight. However, even the moon has a small gravitational field, even though it is much less than the Earth's. The net impact is one must still boost billions of tons of mass into place before _any_ useful work can be done with the elevator. You will need some _very_ large scale projects in mind to justify its existence.

    To me, it seems much more feasible to use the moon or the asteroids themselves as the launching point for large-scale projects. Almost all of the basic materials are already there. Water and other volatiles can be shipped up from Earth when necessary.

    Bob
  • Go back and reread the end of Fountains of Paradise. The answer is obviously, all of the above, add in a few towers to sea platforms, for good measure. Then in the ring at GSO, put in a race track, and we can have the, "A.C.Clarke 140,115 Race" every year.
  • mcmonkey wrote:
    Where are they going to get a base tower 50 Km tall? The tallest buildings are the Petronas Towers, both under .5 Km, so they're talking about something 100 times taller. In the 60-odd years between the Empire State Building (1931) and the Petronas(1996), the height of the tallest building increased less than 20%. So...last 70 years, 20% growth, next 50 years, 10000% growth.

    The reason we haven't built bigger buildings has a lot more to do with economics and logistics than with technology. For instance, Frank Lloyd Wright proposed a mile-high tower called The Illinois [povray.org] that was never built ... not because we couldn't (we probably could), but because nobody wanted to pay for it; one building that size would double the commercial real estate in downtown Chicago all by itself; the higher the building, the greater a percentage is devoted to dead space in elevator tubes that serve higher floors; and just logistically getting everyone who worked there to their desks in the morning would take all the transportation capacity of a modern major city, all pointing at maybe four square blocks, and taking six hours to fill and then empty the building.

    And what happens when something flies into this thing? Heck, birds have trouble avoiding wind mills, so I expect this will generate a fair amount of road kill. I certainly wouldn't want to be on my way up when an airplane hits.

    Well, one would hope that would never happen. But I'd rather ride on an elevator than a bomb made of rocket fuel. (R.I.P. 51-L)

    FYI, Canadians: the committee on tall buildings ruled that Petronas is the tallest building, while CN Tower is the tallest freestanding structure. They're really not comparable.
    ----
  • The only new thing in this article is that carbon nanotubes, which actually exist in small quantities, might be strong enough for the tether. That's encouraging; some previous writings on the subject had required the existence of materials you can't make out of atoms.

    The basic flaw in the idea is that you need the technology to move massive amounts of stuff into space to build a tether, and if you have that technology, you don't need a tether.

  • An airplane has hit the empire state building. The building survived. If you hit a cable of carbon nanotubules with an aircraft, it would most likely cut through the aircraft.
  • They'll be done when I'm 80, I can take a trip up and annoy people the whole way with stories of my gall bladder operation. Wanna see my scar again?
    That's a pretty long time to be stuck in an elevator with tourists.
    (Fountains of Paradise was a great book, BTW.)

    The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk

  • Where will they put it? (Score:4)

    by Hairy_Potter ( 219096 ) on Friday September 08, 2000 @03:45AM (#794815) Homepage
    It has to be very near the equator, which really limits the places. You want to have a stable, reasonably high tech place that you can get to easily. I mean, you don't want to spend trillions of dollars to build it, and have it be destroyed in an uprising.

    Looking at the equatorial slice, you have Central and the northern part of South America. That's close to the US, but the only country in that area that sounds somewhat reasaonable is Venezuela. I think they're stable, and at least somewhat technically clueful. A shame there aren't more, as close to the US is a major plus, since American will probablly pay for most of it.

    Going East, we get to Africa. Enough said there, I wouldn't invest a significant amount in Africa until it gets more stable.

    Further East is India and Sri Lanka. India would certainly be a possibility, they have high tech, they speak English.

    Still further East is Singapore, Indonesia and the Phillipines. Shades of the Cryptonimicon. While Singapore has a harsh dictatorship, it is stable and high tech. Indonesia and the Phillipines have too many trouble.

    Counting the votes, it looks like Singapore is it, which is a shame since they're so far from the US. Oh well, maybe the Asian tiger will rise again.
  • They make good sense, especially if we are commented to doing something more than the current small commitment to space.

    Is it just me or does this sentence make absolutely no sense?

  • Cost estimate needs refinement (Score:3)

    by Bruce Perens ( 3872 ) <bruce@perens.com> on Friday September 08, 2000 @07:44AM (#794820) Homepage Journal
    It doesn't seem that the cost-to-orbit estimate amortizes the cost of the structure - it just mentions electrical power.

    Thanks

    Bruce

  • if that cable snapped while still within the earth's atmosphere, you'd have one hell of a mess. They'd be chiesling you out of the bottom of the elevator shaft for years.

  • Re:Where will they put it? (Score:4)

    by remande ( 31154 ) <remande@@@bigfoot...com> on Friday September 08, 2000 @05:54AM (#794824) Homepage
    People have been noting that you can't predict the political situation fifty years from now. Fifty years is the tip of the iceberg. If you are going to build a trillion-dollar artifact, you are going to build it to last a millenium, at least. And no one country is going to be trusted with it. You are going to need a coalition of the big governments in order to get this going. If the lower terminus is on land, that land won't belong to a country (at least when we're done with it). It will belong to some multi-national protectorate. The alternative is that the lower terminus is right on the water. Remember that orbital forces are holding this up, so it's not resting on the ground. Either way, the tech level doesn't matter. Most of this will be built from orbit anyhow. By the time the terminal buildings are created, the most backward region will have tons of tech there to build it. Side note: you want the cable to be as simple as possible. No moving parts. Don't attach it to something like a building. We'll go through dozens of spaceports before the cable fails.

  • Structural integrity.. (Score:3)

    by VWswing ( 74185 ) on Friday September 08, 2000 @03:45AM (#794825) Homepage
    They dont give much details, but friends of mine
    have been discussing the ideas for years..

    Is it really possible? I mean 33km of material is going to weight a lot unless it's made out of feathers or intestine.. and I'm sure those materials have weight as well, and aren't that structurally sound..

    This was talked about a bit in Arthur C. Clarke's book, space oddyssey 3001 .. though what I liked in his book was the idea of a "space elevator" on the planet of europa to send out spurts of water (turning it into a spinning sprinkler system) which would then freeze in space and be used to cool down & colonize other moons/planets..

    What I really want to know.. is has MUZAK International already started planning on how they're going to insert their horrible string versions of american pie into the space elevator?
  • Why exactly is it believed that such a system would reduce the cost of orbiting something? IIRC, we already recover and reuse the boosters and tanks from the Shuttle, meaning that it's mainly a matter of refueling the things and fixing the stress damage. Therefore, it seems like the main cost of getting to orbit is energy (well, that and building vehicles that don't fall apart on the way up), and my rudimentary knowledge of physics says to me that you're doing the same amount of work no matter how you get up there.

    I can see an argument that the elevator might need less control/support architecture than the Shuttle, but presumably once you're up in orbit you'll need to move off the tether and remain alive for a few hours, so that equipment still needs to be hauled up. (I suppose we could also be assembling all our orbital vehicles up there, so that you just take the elevator up to a space station and hop into an orbiter which never had to be brought up from Earth, but that's a long way off...)
  • Three other factors (besides the ones you mentioned) come into play here. First, the need to avoid any type of local storms. Second, relative geological stability. Third, if you can get a couple of kilometers of free height it cuts your costs somewhat.
    To get these you need to look for a relatively stable mountain range on the lee side of the prevailing winds. The only mountains near enough the equator are in Kenya with Mt. Kilamanjaro and the Andes on the side away from the Pacific. Since the African rift valley probably isn't stable enough, it looks like Peru/Brazil will be the likely winner.
  • Admittedly, it would be swinging wildly several miles up, where there really isn't much to destroy.

    As for balance, it should be doable to counterbalance all weight transfers -- all you need is to deploy / reel in a weight spaceward.

    More fun is angular momentum. Recall that the top of the tower up in geostationary orbit is moving a lot faster sideways than the bottom. So while the steady state would have the bottom of the tower hanging straight down, regular use will have it curving East, probably quite sharply.
  • You may want to read that article again. Nowhere did it say geostationary orbit is 50km. The proposed cable would be attached to a 50km tower (which is fairly amazing in itself, if it happens). Geostationary orbit is somewhere around 22,300 miles.

    "Diamond fiber" is a nice science fiction device. Maybe there will be such a material, maybe not, but it's largely irrelevant. You need something with an insanely high tensile strength, or a cable which tapers a lot more. Basically, at any point along the cable it needs to be wide enough to support the material below it. Higher points carry more weight, so must be thicker. As mentioned, you could build it from steel, if the taper weren't prohibitively high.

    That said, most of what we've accomplished today probably looked fairly ridiculous from a 1950s vantage point. As technological advance continues to accelerate, predicting the world 50 years from now becomes that much more error prone. We landed on the moon 30 years ago, and I would have thought in the intervening 30 we'd at least make it to Mars. Technologically we can, we just lost interest along the way.

  • Um..yeah. But, ever see "Speed?" Terrorists love elevator brakes. Boom...Snap...Splat.

  • Are you being Served? (Score:4)

    by deefer ( 82630 ) on Friday September 08, 2000 @03:46AM (#794839) Homepage
    "...ninethousandth floor, geosynchronous satellites, Debian CD's, ladies lingerie... Please mind the detritus as you step out of the elevator, and don't forget to put your space helmet on!"

    Strong data typing is for those with weak minds.

  • Let me see...

    • A computer is just a calculating device, ultimately, so the day the abacus was invented, that problem had already been solved. Everything else was a mere matter of scalability.
    • In the 1940's, transmitting digital information around a cable network had already been achieved. No big feat. Wave Guides were well-known, and well-understood, even earlier. The precice application may be new, but the understanding is positively ancient.
    • Man on the moon was conjectured by the Ancient Greeks, who also had workable theories on Robotics, Hydrodynamics, Steam & Rocket propulsion, etc.
    • The Atom is a mis-nomer, as it literally means "the smallest thing possible". Which "atoms" as understood by us, aren't. In fact, atoms were fairly well understood to be composed of smaller particles, much much earlier. Artifacts found in Mesopotamia indicate a working knowledge of the atom being comprised of charged particles.
    • The Great Pyramid was no great feat. In fact, the Pyramids in general are pretty trivial pieces of engineering, requiring only a basic understanding of gears, levers, the A-frame, the Center of Gravity and the Center of Mass. All of which the Egyptians (and many other civilisations around the world) had. In fact, the sheer number of "impressive" works from this period (eg: the Comet Stone, the Pyramids, Avebury Circle, etc) indicates that this knowledge was both ancient and near-universal by the time any of the surviving sites were ever built.
    • Log rollers are trivial. Smooth them off a bit, grab some village yokels and create a moving platform. Doesn't have to move far. To the nearest river'll do. Then just float the logs to near where you want, roll them just short, and dig. The pit must be \| shaped. Then roll the stone in, and use the first roller (which will have fallen in) as a hinge, to right the stone. As for the circle, you just dig the pits in a circle-shape, and that's how the stones'll line up. Duh!
    • The kings and queens of Europe are simply one form of unelected, all-powerful power-base. The international mega-corporations are another, and the intelligence agencies are a third. So we don't call those "kings" and "queens". So what? They serve the same purpose, they do the same things, and they are identical, politically.

    Far from going on, the list barely even begins. Almost anything "considered" impossible has NEVER been considered "impossible" by humanity as a whole, merely by the people with the most books.

    Was it "impossible" to sail round the world, in Columbus' time? No! Columbus obtained maps showing a round world, and explorers' reports from those who had ventured futher than any "official" land. He also had the Greek's calculation showing the circumference of the Earth, and numerous other pieces of information, collected from around Europe and the Mediterranian.

    The "fact" that popular myth =LATER= made him a dashing hero, who was the first to imagine a round world, is laughable. Furthermore, it's an insult to Columbus' intelligence, his detective skills and his competency as a sea navigator.

    After the fact myths always reduce how much "the poor leetle primitives" knew. The fact is, they weren't stupid, and weren't that primitive. IMHO, the primitives are modern folk who feel that the only way to feel pride is to put their dead ancestors (who can't talk back, or kick up a fuss) as far down the ladder as possible.

    Superiority by Imposed Inferiority is nausiating and needless. And WELL beyond where any Slashdot reader needs be.

  • For example, let's say we have a Mexican engineer (for instance, me), a Russian mathemathical expert, a Hindu computer programmer and a Japanese nano-technology expert

    What does being Hindu have to do with what language you speak? Last time I checked, Protestants don't all speak English, Eastern Orthodox Christians don't all speak Greek, Muslims don't all speak arabic. Maybe you meant Indian programmer. But the problem with that is India has 18 official languages and no one language is spoken by the majority.

  • Oi (Score:3)

    by Misfit ( 1071 ) on Friday September 08, 2000 @03:47AM (#794851)
    No way. I can't even ride in a galss elevator without looking directly at the ground.

    I hate elevators, and I hate heights. This is stressing me out just thinking about it.

    Misfit
  • Phil Reed wrote [responding to someone else]:
    >>Everyone keeps trying to do these space stations that keep failing and falling apart.
    >Uh, exactly HOW MANY space station has there been? I count one.

    Actually, there have been several Soviet-Russian stations [friends-partners.org] over the years, of which Mir is merely the latest.

    The International Space Station is not yet commissioned

    Commissioned? It isn't permanently occupied yet, but it's certainly operational.

    so the only example I can think of is Mir. To ask why it's falling apart, you only have to look at the government that's running it. One example does not make a trend.

    More pointedly, Mir is well beyond its planned operational lifetime. When ISS is 10 or 15 years old, it too will start to have "issues". You simply can't bring a module back to earth for service -- so if something breaks, well, it breaks in orbit. What else would you expect?
    Nevertheless, Mir-Shuttle (otherwise known as ISS Phase I) was a valuable learning experience, and ISS will not run anywhere near the energy starvation levels of Mir, and NASA has plans to give ISS much more redundancy in propulsion and control as it grows.
    ----
  • When I read this my first thought was:

    Man is Toronto going to be ticked.

    They are very fond of their tower. See CN Tower [toronto.com]

  • Read the arcticle. The technology required to build a space elevator will be available in 50 years, and then humanity is able to build one. And this is going to take another 10 years at least, and maybe by then other ways of fast anc cheap travel to space will be available..
  • Actually, the US and Russia do/did have ASAT programs that was pretty successful. We mothballed our missile based ASATs, I believe, but we are still playing around with our lasers along with their other capabilities.

    Links of interest on FAS

    Some stuff on Russia's programs [dn.net]

    Some general stuff on all sides [dn.net]

  • Sounds like SpacePorn(tm)! (Score:5)

    by FascDot Killed My Pr ( 24021 ) on Friday September 08, 2000 @03:51AM (#794864)
    Why does "riding the space elevator" sound like something Kirk would say to Spock (or "Bones") after visiting The Planet Of Scantily Clad Green Women?
    --
    Linux MAPI Server!
    http://www.openone.com/software/MailOne/
  • Do you realize that the description you've just given also applies to Hoover Dam? The only distinction is how rapidly the material gets (re)distributed.


    Another distinction is the area affected. A dam burst, even one of Hoover's size, would be confined to a relatively small area. A falling beanstalk could potentially hit the entire equatorial region, encompassing hundreds of thousands of square miles and many political jurisdictions.

    It seems to be getting harder and harder to erect the large-scale engineering projects, either because of their perceived danger or just the NIMBY syndrome. New dams are fought tooth-and-nail, and you'd probably have more success building a nerve-gas plant than a reactor for nuclear power. A beanstalk would bring together all of these oposition forces.

  • Elevator Disasters (Score:3)

    by gandalf314 ( 73188 ) <synergy314 AT excite DOT com> on Friday September 08, 2000 @03:52AM (#794877)
    Fortunately, when the cab is decending the cable, it doesn't need a heat shield because it is dropping at a controlled rate and not dropping out of the sky like the Space Shuttle. The Shuttle is accellerating as it falls so by the time it hits the outer atmosphere, it's going pretty fast and generating a lot of friction. As far as terrorist bombings, the whole cable, all 25,000 miles of it plus counter weight, wouldn't fall out of the sky. If the base anchor was bombed then it would just kinda hang there and drift around a little. But if it was bombed towards the middle, then half would rain down on the earth and the GEO station would just stay there.
  • Except, if you review the article, at this point they postulate that the tower would _collapse_ without the tether and the counterbalance. Do try to pay attention.
  • If the cable broke it would wrap around the equator. Probably it would hit some land somewhere along the way, considering that it would wrap most of the way around the globe. This assumes that it breaks 22500 miles up at the point of max tension.

  • ..But Can They Patent This Idea? (Score:3)

    by skurk ( 78980 ) on Friday September 08, 2000 @03:54AM (#794888) Homepage Journal
    As I recall, a similar concept were presented in a Donald Duck magazine a few years ago: The idea was produced by Gyro Gearloose. Scrooge McDuck's money bin was lifted into space by using a similar device, so his money could be safe from the Beagle Boys.

    Isn't there a law prohibiting patents of ideas already invented?

    -skurk
  • >We have no way of knowing what it will be like in these regions in 50 years.

    That is true. But consider this: I think it is a reasonable hypothesis that the condition of those regions in 50 years would be considerably better *with* the elevator than without it.

  • Red Mars, Green Mars and Blue Mars. They go into great detail on the building and maintaining of space elevators, as well as a spectacular description of what happens when one comes down...
  • How exactly did the Mesopotamians figure out that:

    a. Matter is composed of atoms
    and
    b. Those atoms are composed of charged particles?

    From what I remember of Meso. history, it seems a bit beyond the technology of the time. Please enlighten me, I'm very interested to hear this.

  • Space Elevator Design (Score:5)

    by DanielRavenNest ( 107550 ) on Friday September 08, 2000 @08:29AM (#794897)
    I was a participant in the Space Elevator workshop that led to this news item. I would like to make several comments on space elevator design:

    1) A ground to synchronous orbit (35,000 km high) elevator is often discussed, but such a design is neither necessary nor economic.

    A segmented elevator cable in earth orbit plus
    orbit mechanics allows you to get around with only 1/7 of the height in actual cable segments. You coast between cable segments.

    A tower from the ground several tens of km tall
    saves you most of the losses that a rocket like
    the shuttle sees from trajectory inefficiency and atmospheric drag. You simply launch from the top of the tower.

    2) A real space elevator design will have multiple redundant cables because natural meteoroids and manmade orbital debris will occasionally run into the cable sections. The cables will be cross-connected so that the loads will be routed around any break (kind of like packet routing for the internet). You will have robot 'spiders' that will carry replacment spools of cables and be able to replace broken sections. This maintenance is like painting bridges continuously to keep them from rusting.

    3) Existing high strength carbon fiber (1 million psi strength) is sufficient for economically rational space elevators. Carbon nanotubes are
    strong enough for a 35,000 km space elevator,
    but they would also make possible ultra-light rockets that would eliminate the cost justification for such a large elevator.

    Daniel
  • Nothing untoward happens to the Earth's rotation at the solstices.

    However, there's a problem I don't know if anyone has thought of. Geostationary orbit is one tenth of the way to the moon. Tides could be a problem.

    --
  • The efficiencies of the space elevator are from two sources. First, conventional chemical rockets are not energetically efficient. But there are many near-future improvements on that score, ion drives and the like. More fundamentally, the problem with any rocket is that you have to carry around your reaction mass (the stuff that goes down equal-and-opposite to you going up). If you can somehow push off of the earth and/or harvest your reaction mass from whereever you happen to be, you can get almost as much efficiency without this obscene amount of infrastructure.

    Push off the earth: that would be a rail gun. The only problem is, if you're accelerating sattelites up the side of a mountain to supersonic speeds, it gets pretty loud. Local people (not to mention birds and animals) complain. The noise is the primary reason that ideas for a Hawaiian orbital railgun don't fly very far. The problem isn't technical, it's social, and so it's much harder. Tyranny is the only easy answer, because there are plenty of people who wouldn't tolerate incessant sonic booms for any amount of money or government carrots, and that's their right.

    The other half of the answer is space elevator(s) in space. Huge cables are much easier to build when they don't have to deal with the atmosphere or be geosynchronous overall. You grab the bottom, run up to the top, and let go. Wait a minute, you say; now the cable itself is your reaction mass, so why doesn't the cable's orbit decay? Because you're pushing against the earth's magnetic field with currents through your cable.

  • Uh oh... (Score:5)

    by gughunter ( 188183 ) on Friday September 08, 2000 @03:58AM (#794904) Homepage
    Not long after construction begins, all the workers will begin speaking different languages and the project will be abandoned. It's happened before...
  • Disperse life now [geocities.com] -- not in 50 years.

    People keep thinking there has to be some international mega engineering project before we can disperse life. There doesn't, and relying on such a project will guarantee failure for the same reason that political leaders have increasingly drawn population from the countryside into the cities:

    Central authorities want control because that's what it takes to become a central authority and dispersion means loss of control.

    Read the above sentence over and over until you either get bored or you finally understand why central authorities are not your friends.

    Positive sum games like the Internet happen despite central authorities, not because of them.

  • actually if it broke in the middle, the bottom half would fall to earth and the top half would be flung into a higher orbit. If it broke high enough, it would reach escape velocity and leave orbit completly.

  • Re:My thoughts... (Score:3)

    by Kintanon ( 65528 ) on Friday September 08, 2000 @08:40AM (#794915) Homepage Journal
    Please, bring up some more irrelevent arguments for this article. Here's a thought: I'm going to make this super strong material that'll let me build a space elevator that'll let people get there on $222 each way! Oh well I have no clue what the hell I'd make it out of, and I have no clue how much it'd truely cost, but if it cost X, and you split it up by Y, etc. etc.
    Give me some facts. Research it. Show the material. Do some tests. Put up some data. None of this assumption crap. The Scientific Method is what defines science and helps us describe our environment. I see no evidence of that here. Just a bunch of assumptions and "cool shit". What I'd love to know the most is: How the hell do they go about constructing this? Obviously from the top down. How many rockets does it take to put this amount of crap in space? How the hell do they expect to get an asteroid... thats a big deal... How do they expect to build it? People, machines? etc. etc. etc.


    Well, as mentioned in another post there is a carbon molecule with higher tensile strength than diamond that is in development that can serve this purpose without snapping or shattering. Once that is complete the rest is just details. To me the hard part will be joining the cable segments since your joint compound is going to certainly be weaker than the cable itself. And they definately aren't going to create a 144,000KM cable in once piece on earth and then stand it up.

    Kintanon
  • While I agree with several things DHartung wrote, and I disagree with several other points, there's one thing I'd like to speak my mind about:

    What kind of incompetent school did you go to, that you believe speaking English is a pre-requisite for mastering high technology?
    Actually, I'd say that as of today, speaking English is a pre-requisite for communicating with people in the area of high technology.

    For example, let's say we have a Mexican engineer (for instance, me), a Russian mathemathical expert, a Hindu computer programmer and a Japanese nano-technology expert. Add in a couple of European team members, and you definitely have to have a common language. English, right now, is such language. Maybe in 50 years it'll be japanese or french or tagalog, who knows?

    The point is, it's not a matter of nationalistic pride or anglo-centrism (if there is such a word). It's a matter of convenience.
    1. It's impossible. They couldn't get even a short tether to work, without it melting from the current induced in it. This will need to be MUCH longer.
    2. It's impossible. The tether will have to be flexible, or it'll snap. (Remember, s = d/t, and the circumference of low-orbit is quite a bit greater than that on the surface.) Even then, the stress will be fantastic.
    3. It's impossible. The criteria for a line-based elevator is totally contrary to the criteria for a structure that can handle the forces involved.
    4. Lastly, it's illegal. If the elevator or cable travel within 10 miles of any other national border, that nation is entitled to claim trespass on their national territory, up to and including shooting down the offending object.
  • It so happens that Slashdot has two articles on carbon nanotubules today...one on their heat conducting properties, the other on its potential use as a rigging cable for a space elevator.

    The space elevator article said that the carbon nanotubules may have a strength as high as 200 giga pascals. However, this article says

    "Ironically, the same weak linkages that make carbon nanotubes superior for heat conductance could deflate scientists' earlier expectation that bun-dles of them would provide unrivaled mechanical strength."

    Umm...I think that the scientists from the second article better call the scientists in the first article. :-)

    Did anyone else notice this?

  • And on a longer timescale... (Score:5)

    by trotsky ( 96716 ) on Friday September 08, 2000 @04:03AM (#794932)
    "At the moment, Sri Lanka lies between 6 and 10 degrees north" Do they intend to move it or just wait till precession moves the equator closer?

  • No idea about the patents... but, had you read the article, you'd have seen that the idea goes back much farther than that Donald Duck story...

    For better insight into the matter of space elevators, you might want to read the mars trilogy by Kim Stanley Robinson, on how such a thing would be built, an on what the consequences of its downfall would be. Of course there's ACC's books, the Night's Dawn trilogy by Peter F. Hamilton etc. which use the theme.

  • Oh, I dunno. The creator of Star Trek is now permanently resident on the moon. The Voyager and Pioneer probes are interstellar. And Airfix are making aeroplanes as fast as they can.
  • It might be possible to build something similar to an oil platform, or possibly even make us of a decomissioned one.

    It's fifty years out though, there's no guarantees that any presently stable government will still be stable nor any presently unstable government won't be the model of stability.

  • They'd better offer some good music... And what about that strange silence when you get into an elevator with a stranger...woah...5 hours worth of silence... - [jeff]
  • What I meant to say is that...if the elevator was STILL in the earth's atmosphere, AND the elevator's cable BROKE...it would plung to the ground.

  • Space Elevator Under Repair.
    Please Use the Stairs.

    Thank You.

    The Management.

  • The Equator... (Score:4)

    by adubey ( 82183 ) on Friday September 08, 2000 @04:22AM (#794952)
    Doesn't pass through India or the Phillipines.

    Are the close enough? I don't know enough physics, but the article makes it sound like if you get too far away problems arise - both with the orbit and with atmospheric events like cyclones, etc. Both India and the Phillipines are known to have cyclones and typhoons.

    You also miss some important countries. Most importantly, Brazil (equatorial rain forest, anyone?)

    Brazil is known as "the perpetual country of the future". Today, the future looks closer than ever for Brazil. Brazil's democracy is solidifying to the point where today one of Brazil's foreign policy goals is furthering the cause of democracy in other S. American countries (Peru is a current target). While the financial system is still modernizing (witness the 1999 currency devaluation), Brazil is on it's way to becoming a low-inflation, high-growth economy.

    While Brazil is still decidedly "low-tech", it is modernizing quickly, in part to due it's large population, in part due to it's realative wealth compared to other third world nations.

    Also: as others point out, by the time it becomes feasible to build the elevator, Indonesia and parts of Africa may become much more stable, which may make them more attractive choices (especially Indonesia - after a few years of solid democracy, all the things I said about Brazil may be valid for Indonesia). Moreover Singapore has a downside... is there enough space to build an elevator there?
  • yeah.. the US needs a new panama-canal...
  • Can anyone explain why you'd need such a tall base station? The only reason I can think of is that gravitational effects are so much smaller at 50km up... Is that the only reason?
  • <I>Perhaps Africa is stable and growing then, </I>
    <P>
    Surely you are not THAT blind of what's going on in Africa. The AIDS crisis there isn't even warmed up and it's causing havok with, well, everything. And unless someone comes up with a free cure for AIDS, things are looking bad for them.
    <P>
    Real bad.
  • from John Varley's Steel Beach. In the book he was talking about a ballistic Lunar roller-coaster type thrill ride but it applies here I think.

    1. "You ever ride that thing?"

    2. "No."

      "I did. I swear, I think my ass sucked up 6 inches of seat foam."

    Which is probably how half of the population would feel about riding something like this.
  • Clarke is very fond of creating amazing structures in his stories. My favourite one was from 3001. This consisted of four huge towers in four equally spaced positions around the equator. Each of these towers was then connected at the top by a huge ring circling the earth. All of this was of course a habitat for the ever expanding population of earth. It also eliminated the need for satelites. Now that would be quite an engineering feat, not to mention a spectacular view. Imagine a base jump off of one of those ;)

  • I forgot to mention that I would line the drilled hole with carbon nanotubes and have big fans either end.. ;P

  • Re:My thoughts... (Score:5)

    by cybercuzco ( 100904 ) on Friday September 08, 2000 @04:46AM (#794989) Homepage Journal
    Youre right, it is impossible, using todays technology, just like it was impossible to build computer that can fit in the palm of your hand 50 years ago. Lets see if any Physical laws are broken in your statements of impossibility. 1: Its not impossible, were talking about 50-100 years from now, some room temp superconducter running the length of the cable will be both lightweight and conductive enough to eliminate the melting problem. Barring this, you can run a stopping voltage into it to counter the current, which is what they could have done in the experiment you mention, except that they were trying to create a current, the stopping voltage actually also helps with...
    2: Its not Impossible With the stopping voltage, and some power taps into the upper atmospheres plasma, you could effectively control the location of the cable. Additionally, you coulduse this to help control tension and compression in the cable. Flexibility isnt too big a problem, most things are pretty flexible when theyre 144000km long. Think of it this way, take a foot long peice of structural steel and try to bend it, doesnt work too well. Take that same peice of steel and make it 110 stories tall, and see how much it bends in a high wind or an earthquake.
    3: Would you like to back this claim up with some actual facts?
    4:If this is true, then why didnt the soviets shoot down our spy satellites? Why dont the iraquis? why dont we shoot down the russians?clearly we have the capability.National territory only goes up so far, something like 160 km, since there will be a tower 50km of that way, there isnt too much room for movement, and even then, why would you want to do it?

  • IF they could really build a 50KM high tower, you could put a mag lev launching rail up the side, and use that toaccelerate spacecraft. Forget about the space elevator.

    At 50Km you are basicaly free of the atmosphere and the enrgy need to rasie the spacecraft out of the atmposphere and accelerate it to whatever speed it gets too after 50km comes from the ground, drasticaly reducing the weight of the ship. (The Shuttle weighs less than 1/2 what it did at launch a mere 2min after lift off and is no where close to 50km up)

    Such as system would drasticaly reduce the cost per pound to orbit.
  • There was a corny episode of Star Trek:Voyager about a space elevator. It was as big as a Studio apartment, and seemed to have all sorts of wacky problems.
  • I found this website [spacefuture.com] which suggests that a smaller scale space elevator could be built using existing materials.

    It gives the facts and figures on an 860 mile long elevator as opposed to the accepted idea of a much longer elevator.

    Interesting.

    The one engineering problem I forsee is the ground platform which would have to be a minimum of 50Km tall to adequately serve the elevator. This is a huge obstacle to overcome. The current tallest buildings are a little over .5 KM IIRC. This presents a major construction problem that no one has found a solution to yet.

    Any idea's? ;-)

  • Re:Cost of transit to orbit (Score:3)

    by LetterRip ( 30937 ) on Friday September 08, 2000 @06:16AM (#795003)
    "Therefore, it seems like the main cost of getting to orbit is energy [...] and my rudimentary knowledge of physics says to me that you're doing the same amount of work no matter how you get up there. "

    The point that you are missing is energy effeciency of the device used to get up to space. While the "absolute minimum" energy requried is a hard limit. The maximum energy used is not. Also, using rockets, you have to carry your launch fuel with you, which is heavy and spendy. Using a space elevator you only need to carry fuel that you need to manuever once you are in space. That is why a space elevator would be so much cheaper.

    LetterRip
    Tom M.
    TomM@pentstar.com

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