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Space Science

Space Elevators: Low Cost Ticket to GEO? 429

Posted by michael
from the seven-days-of-muzak-and-seven-more-to-go dept.
Crocuta writes "The current issue of Science News features a cover story that discusses the current developments in space elevator technology. NASA has been working on such devices for many years, but private companies such as Highlift Systems are now jumping on the space elevator bandwagon, no doubt seeing the huge potential profit in a low cost per pound delivery system. PhysicsWeb has a somewhat older, but much more technical article on the formation and structure of the carbon nanotubes that form the basis of the proposed tether cables. With a development like this, we could shoot entire boy bands into space and make the world a better place."
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Space Elevators: Low Cost Ticket to GEO?

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  • by keep_it_simple_stupi (562690) on Tuesday October 08, 2002 @02:32PM (#4411432) Homepage
    We have enough trouble getting stuck on elevators between floors in 5 story buildings. Could you imagine getting stuck half-way to the moon? They better be sure to put one of those bright red emergency phones on this bad boy.
  • what about deep space? if we accelerate the payload up the space elevator wont we also get the slingshot effect of the earth's rotation adding to the energy we are putting into the payload to get it flung toward the outer planets at a much higher starting velocity and while using less fuel?
    • The "slingshot effect" is only useful for trajectory changes. It allows one to save fuel when changing directions. Due to conservation of energy, when you approach a planet and slingshot away from it, you end up with the same velocity on the way out as the way in. You will accelerate as you approach a planet, but you will decelerate the same amount on the way out.
      • Just a minor clarification on the parent...

        The "slingshot effect" is only useful for trajectory changes. [cut] Due to conservation of energy, when you approach a planet and slingshot away from it, you end up with the same velocity on the way out as the way in.

        This is correct enough, but for those who haven't taken an orbital mechanics class, I thought I'd chip in a little bit more info. The 'slingshot' effect seems to work since you (the object) is changing frames of reference into- and out of the planet being used. (The other frame being with respect to the sun.) Additionally, you have to do the approach from the 'backside' so the planet pulls you forward on your way by (assuming you want to gain speed; otherwise enter on the front-side to slow down).

        Once you leave the sphere of influence of the planet itself though, and are only under the dominant effect of the sun (i.e., changed frames of reference) you have changed net velocity (speed as well as direction).
      • by Soft (266615) on Tuesday October 08, 2002 @03:22PM (#4411841)
        The "slingshot effect" is only useful for trajectory changes. It allows one to save fuel when changing directions. Due to conservation of energy, when you approach a planet and slingshot away from it, you end up with the same velocity on the way out as the way in. You will accelerate as you approach a planet, but you will decelerate the same amount on the way out.

        All true, but you missed two points:

        • in a slingshot maneuver you cannot, indeed, gain velocity relative the planet you approach; you can (and space probes do) gain velocity relative to the Sun, since said planet is moving with respect to the latter;
        • the original poster, I think, did not have a gravitational slingshot in mind, but the effect you would get if the top of the elevator were above GEO, you could launch objects that way.
      • by ENOENT (25325) on Tuesday October 08, 2002 @03:23PM (#4411851) Homepage Journal
        BZZT!!! No, you're forgetting that the planet has its own velocity, which a spacecraft can steal. When a spacecraft slinshots around a planet, its velocity on the way out is the same as its velocity on the way in, but this the the velocity RELATIVE TO THE PLANET. If the spacecraft approaches the planet head-on, and does a 180 degree slingshot around the planet, then (ideally) its final velocity RELATIVE TO THE SUN is equivalent to its initial velocity plus two times the planet's orbital velocity. Energy is conserved, because the energy gained by the spacecraft is stolen from the planet.
      • Insightful? Try (-1: Wrong). The slingshot effect is useful for changing the magnitude of (increasing or decreasing) velocity. Why the hell do you think NASA missions use all those flybys of the earth, venus, mars, etc? The slingshot effect speeds up the probe while slowing down the planet. Don't make me break out my astrodynamics book on you ;)
    • what about deep space? if we accelerate the payload up the space elevator wont we also get the slingshot effect of the earth's rotation adding to the energy we are putting into the payload to get it flung toward the outer planets at a much higher starting velocity and while using less fuel?

      Yes, if the top of the cable is higher than geostationary orbit (which will probably be the case, since the thing's center of mass has to be in GEO itself...)

    • Um, no. That's not how the slingshot effect works. It's not free energy generated by a planet's rotation.

      I'm not expert, but I think the key to the slingshot effect is that you always receed from a planet's gravity well at the same speed as you approached, but nobody ever said it had to be the same direction. So, to put it simply, suppose a certain planet is travelling at 100m/s relative to the sun, and you are sneaking up behind it at 120m/s. Relative to the planet, you are approaching at 20m/s. After you pass it, you'll receed at the same speed, 20m/s. If you choose to receed from the planet in the direction it's revolving, then you'll leave at 140m/s relative to the sun, having acquired the additional 40m/s at the expense of the planet's kinetic energy.

      Of course, this is a one-dimensional example of a three-dimensional phenomenon, but you get the idea.

  • by khendron (225184) on Tuesday October 08, 2002 @02:34PM (#4411450) Homepage
    And I'll say it again. I *love* the idea of a space elevator. But I do not see how it will reduce the cost of going to space as much as some people claim. The maintenance costs for the tower will be tremendous.
    • by mikeee (137160)
      Maybe. But it's hard to see how they can be worse than the 'maintainance' costs of rebuilding the whole damn rocket every time you launch one.

      Yeah, yeah, the shuttle is reusable, but disposable rockets are actually cheaper than that engineering nightmare, from what I read...
    • by sketerpot (454020)
      The tower shouldn't be too much more expensive to maintain than the NASA Shuttle fleet, in my estimation. The ribbon itsself would be very strong and placed in an area with very mild weather. And it would manage to lift about a ton of cargo to space every day!

      That would still be very expensive, but immensely less expensive than using the current methods of reaching orbit for comparable amounts of cargo.

      Of course, my estimates are open to dispute, and I could be wrong. But I don't care: the space elevator is cool!

    • It's easy (Score:4, Funny)

      by theonomist (442009) on Tuesday October 08, 2002 @03:04PM (#4411707) Homepage

      Cars will be drawn to the top of the elevator by a team of trained mules, hitched to a rope of a length roughly 1.8 times the circumference of the Earth. We anticipate only minor difficulties obtaining a right-of-way through most nations (with the possible exception of Sweden, because they're lame).

      The mules will be fed and cared for by dedicated and highly trained staffpersons. At the end of their useful lifespan, most retired mules will be adopted by loving families everywhere. Unclaimed mules will be shot, as will be unclaimed members of loving families. Irresponsible and gratuitously hostile critics, who clearly do not have the best interests of humanity in mind, will be shot also.

      On special occasions and international holidays, children of all races, creeds, colors, and nationalities, clothed in their quaint and colorful native garb, will be invited to throw superballs and apples from the top of the elevator. They will be charged only a nominal fee for this unique privilege. Highly sophisticated surveillance technology will enable all the world to enjoy the festivities!

      We are now accepting investments in this historic, one-of-a-kind investment opportunity, not to be missed by the progressive and forward-thinking investors of our great nation. We anticipate incalculable earnings; we also anticipate neglecting to calculate them. Please give us all of your money right now and I promise you'll not regret having been so easily gulled.

  • by mythosaz (572040) on Tuesday October 08, 2002 @02:35PM (#4411463)
    Those of us already in orbit can't wait for the space elevator to be complete. Finally, we can get some cable TV.
  • Free Electricity (Score:5, Interesting)

    by kenp2002 (545495) on Tuesday October 08, 2002 @02:35PM (#4411466) Homepage Journal
    With an object that goes through t the ionosphere you would get a constant stream of free electrons surging through the damn thing. Throw a power station at the base and BOOM. Free electricity. The only question I have is if we pull down electrons in the upper atmosphere would there be an impact?
    • by i8a4re (594587)
      Well, the free electrons in the ionosphere are a conductive layer that shields us from radiation. So, if you deplete it too much, you'll not only get free electricity, but you could probably get your xray taken just by going outside.
    • Highlift Systems FAQ (Score:5, Informative)

      by TheOnlyCoolTim (264997) <<tim.bolbrock> <at> <verizon.net>> on Tuesday October 08, 2002 @03:30PM (#4411908)
      Will the wire generate power?

      Yes, but only in the milliwatts.

      Tim
    • Re:Free Electricity (Score:3, Informative)

      by deander2 (26173)

      Actually, the "free" energy is taken directly from the rotational inertia of the earth itself. So this would slightly increase the length of our day, but only VERY VERY slightly. When you consider the mass of the earth and how fast it spins, you could power all of humanity for much longer then you could imagine before the earth's day was noticably different.

      Also, the earth's rotational speed changes gradually anyway...
    • Re:Free Electricity (Score:3, Informative)

      by freuddot (162409)
      Useless.

      You'd have the same problem as with any other potential field :

      You get access to particle X at extremity X0 of some energy potential field Y, compared to extermity X1 .

      However, in order to use this energy, you have to put something (a wire) between X0 and X1(the two ends of your elevator). This something(wire) however will receive the same field effect, and will cost you the same exact energy amount.

      In plain terms, you've got to ship back those electrons to the top of the wire, to get electricity. The more easily they came down, the harder it gets to send them back.

      Otherwise, you could do the same in airplanes. Airplanes, while travelling trough the magnetic field of earth build a good potential difference between their wing tips. If you try to use it, though, the wire you put will build the same voltage, preventing you from using this energy.

      BTW, that's also why you can't shield gravity.

      HTH

      J.

  • by Anonymous Coward
    Imagine asking for the basement, (floor -1), and getting sent to floor 65535 instead :-).
  • by Big Sean O (317186) on Tuesday October 08, 2002 @02:36PM (#4411475)
    Arthur C. Clarke popularized the Space Elevator and once said "The space elevator will be built about fifty years after everyone stops laughing".

    http://science.nasa.gov/headlines/y2000/ast07sep _1 .htm

  • by GeneralEmergency (240687) on Tuesday October 08, 2002 @02:38PM (#4411498) Journal


    . ...that when it gets built, the Longshoremen will insist that loading and unloading it is a union job.

    .

  • by night_flyer (453866) on Tuesday October 08, 2002 @02:38PM (#4411499) Homepage
    cant get much lower [autotrader.com]
  • by SexyKellyOsbourne (606860) on Tuesday October 08, 2002 @02:39PM (#4411502) Journal
    As fascinating as it sounds, unfortunately, Congress will never fund such an endeavor -- as far as they concerned, space is a useless void that we now have no reason to explore after the death of the USSR.

    The idea might be feasible -- I prefer the idea of a giant cannon/mass driver/gauss gun to shoot us into space myself -- but the idea of a 100,000km tube supporting an elevator is too farfetched to ever get funding, especially with increasingly conservative US administrations that would rather spend money launching rockets not into space, but into third-world cities, as well as European powers that have their own budget problems due to their social welfare systems that prefer to spend money on Earth and not in space.
  • by L. VeGas (580015) on Tuesday October 08, 2002 @02:39PM (#4411503) Homepage Journal
    The problem with something this tall is that it will inevitably be destroyed, and we will be scattered throughout the earth and forced to speak different languages.
    • The problem with something this tall is that it will inevitably be destroyed, and we will be scattered throughout the earth and forced to speak different languages.

      Or it will just get blown up/flown into/cut down by terrorists.

  • by CSG_SurferDude (96615) <wedaaNO@SPAMwedaa.com> on Tuesday October 08, 2002 @02:40PM (#4411510) Homepage Journal
    Some Books to look at:

    The 1979 Hugo and Nebula Award winning novel, The Fountains of Paradise [sfsite.com] by Arthur C. Clarke.

    AND...

    The Web Between the Worlds [baen.com], by Charles Sheffield, using the same idea, published about the same time Clarke published his book.

    AND...

    Of course, Kim Stanley Robinson's Mars trilogy [oreilly.com].

  • Risky investment (Score:3, Insightful)

    by jukal (523582) on Tuesday October 08, 2002 @02:41PM (#4411522) Journal
    Think of the space elevator structure as a 100,000-km-long highway that will require ongoing maintenance and repair," says Smitherman. It will stretch 2.5 times Earth's circumference.

    How many gazillion of billions do you think it will cost. If not by any accident, how many terrorists does it take to blow it up? There just is not and cannot be such big amount of capital tied into one physical place. It might be possible to build it - once, if you find someone who is ready to BURN that money. Someone who invested all his money into a dot.com in 1999 is worth economics nobel prize compared to this.

    • by Casca (4032) on Tuesday October 08, 2002 @02:50PM (#4411597) Journal
      You build it in the middle of the ocean on an old oil platform. You create a military-like death zone around the platform, say going out 50 miles in all directions. It might be hard to protect something like this built in a city, but in the vast expanses of the ocean, not a problem.
      • Are you 100% garanteed to detect and destroy a submarine? Can you destroy any missiles fired at it?

        I would love to see the elevator built but he's right. How could it be defended from someone who doesn't care whether he lives or dies as long as the target is destroyed?

        • Hell yes. Active sonar is a wonderful thing. Destroy a missile fired at it? Good luck getting close enough to fire one to begin with.


          How could it be defended from someone who doesn't care whether he lives or dies as long as the target is destroyed?


          I think we could make it reasonably difficult for even the most determined nut to be able to harm this thing. Hell, just make everyone who gets near it have to go through an MRI first, just to pick out the people with 5lbs of explosives packed where the sun doesn't shine.

          If we can build it, we should build it. If you aren't moving forward, then you're moving backwards.
        • by Storm Damage (133732) <st0rmd@ h o t m a il.com> on Tuesday October 08, 2002 @03:31PM (#4411917)
          Nothing can be protected 100% completely from attack by terrorists (or anyone for that matter). There is always a risk that if someone really wants to see something destroyed, they can do it.

          That said, however, putting a ribbon to space out in the middle of the ocean, away from any shipping lanes, international flight paths, or human activity at all is a good start at protection. It's HARD to get to a location that far removed from everything without anyone noticing (especially if that location is under constant watch and guard.

          Additionally, this operation, while not devoid of human workers, won't have so many people laboring at the anchor-station or on the cable to make a terrorist attack really that fruitful. There just isn't that much casualty potential (although the capital losses could be considerable).

          But capital is just money. And the neat thing about money is if you spend it on projects which create wealth, you're not really losing it. If the cable can operate for a few years, it will have paid for itself, anyway, and very likely several additional cables will be built to expand capacity. These cables will most likely expand radially from earth all around the equator, under the control of diverse groups of people. We already know that humans want to get out into space and explore it, even at considerable expense. The proposed budget for the cable is not chump change, but nor is it unreasonable when compared to other space projects. America alone has spent considerably more on the Space Shuttle program over the past 25 years, and for that money, we'd be able to lift up as much material (measured by tonnage) in 2-3 years as we have in all the Shuttle missions combined. So the real risk of huge financial loss is if a terrorist destroys the cable in that initial timeframe. Additionally, since most of the cost is in the research, design and development, rather than the construction and deployment, another cable could be built if the first one is destroyed (admittedly, if the first one is destroyed very quickly, there will be a huge political barrier to overcome before a second cable could be deployed).

          Also, since the thing is so cheap to operate, many more nations, companies, and individuals will be able to afford to undertake space-based projects.

          The thing is, if the whole world is given access to space, There won't be that much motivation to destroy the means to that access. If one country or company jealously hordes the cable and doesn't lease out usage to everyone else, that country or company will:

          1. Risk considerable reprisal, both in the form of economic sanctions by the rest of the world, possible military threats, and very likely terrorist threats

          2: Miss out on a fantastic opportunity to enhance the economy of the entire planet, and line its own pockets considerably in the process.

          Therefore, it will be in the interest of whoever builds such a machine to let the rest of the world use it as well, including the deployment of components for the construction of additional cables.
          • (admittedly, if the first one is destroyed very quickly, there will be a huge political barrier to overcome before a second cable could be deployed)

            There's an easy solution to this problem that can be summed up with a quote: "Why build one when you can buld two for twice the price" - S.R.Hadden
        • by jcr (53032) <.jcr. .at. .mac.com.> on Tuesday October 08, 2002 @04:36PM (#4412335) Journal
          How could it be defended from someone who doesn't care whether he lives or dies as long as the target is destroyed?

          How about removing the single point of failure?

          What if the cable split into a few hundred strands, and was anchored in such a way that it covered a good 1KM radius on the ground, with lots of room between the strands? Perhaps a fully-loaded 747 could take out a 747-wide swath of the cable ends, but it couldn't hit enough of them to threaten the overall integrity of the elevator.

          Basically, it's just an engineering problem. A single mass of cable would be pretty difficult to destroy already, and strategies like I've just described could make it even more difficult.

          -jcr

      • >You create a military-like death zone around
        > the platform, say going out 50 miles in all directions

        Did you forget that you do not need to only cover the land area? You need to look up (and you need VERY big googles) and cover every inch in that direction as well.

  • More info (Score:4, Informative)

    by Truckle (601283) on Tuesday October 08, 2002 @02:42PM (#4411536)
    Here are some more links to info on our very own Slashdot:

    Here [slashdot.org]
    Here.. [slashdot.org]
    Here.. [slashdot.org]
    and Here [slashdot.org]
  • I can just hear the laughter from outer-space:
    "GLeebob, come here quick look what those silly humans are trying. Yup, they're trying the ladder-thingy. Remember when we tried the ladder-thingy..Ooooh, that was a dumb-idea. What will they do next, human-pyramid? Come on humans, bang those rocks together..."

  • by Tidan (541596) <tidan_md@@@yahoo...com> on Tuesday October 08, 2002 @02:46PM (#4411572)
    Here's a nice sized (15MB) report [usra.edu] done by NASA. They talk about all sorts of problems that need to be worked out to make get this project off the ground http://www.niac.usra.edu/files/studies/final_repor t/pdf/472Edwards.pdf
  • by peacefinder (469349) <alan@dewitt.gmail@com> on Tuesday October 08, 2002 @02:50PM (#4411604) Journal
    Why stop with one seemingly improbable concept?

    Once the elevator is built, use it to haul pieces of an Orion craft to the top and assemble it there. When it's ready, let it go, flinging it out of Earth's magnetic field. Once clear, light it up and go see the solar system.

    This way there's no radioactive contamination of the atmosphere, minimal risk while getting the "fuel" in orbit, and it's a handy way to get a crapload of plutonium out of our hair.

    Saturn in fifteen years, anyone?
  • Repeat Article Proof (Score:5, Informative)

    by Nintendork (411169) on Tuesday October 08, 2002 @02:52PM (#4411617) Homepage
    The last posting [slashdot.org] about this stuff even had a link in it to a 3rd posting going even further back. Is there really so much interest in these projects to justify the frequent reposts? As far as I can tell, there hasn't been any massive progress to make the justification. Michael, may I recommend a book for you [amazon.com]?
  • Discovered in 1991, carbon nanotubes are long molecular tubes of carbon atoms that resemble cylinders of minuscule chicken wire (SN: 12/16/00, p. 398). The bonds between carbon atoms in this configuration are so robust that, weight-for-weight, carbon nanotubes are at least 100 times as strong as steel. They are, in fact, the strongest material known. A carbon-nanotube string half the width of a pencil can support more than 40,000 kilograms, Edwards notes. That's equivalent to the weight of 20 full-size cars.

    How much could spiders' silk hold if it were that thick? I've heard that its quite a bit stronger than steel, but is it more than 100?
    • How much could spiders' silk hold if it were that thick?

      I can't answer that question, but I *can* say you'd need a lot of friggin spiders...

      • they're creating spidersilk in the udders of goats now, it's called "biosteel". Hooray for genetic engineering! It's really inefficient to harvest silk from spiders, because they're too territorial. The protein from spider silk gets mass-produced in a milk-producing creature, where it can be harvested in huge quantities. Thing is though, from what i remember, biosteel biodegrades (go figure).

        I still want my bulletproof spidersilk trenchcoat, though.
    • So....would you envision 1 really huge spider to spew out that silk, or a whole shitload of normal spiders.

      Sounds like a bad sci-fi plot...earth overrun with zillions of spiders as a result of a space elevator project gone awry.

  • I knew it (Score:5, Interesting)

    by Docrates (148350) on Tuesday October 08, 2002 @02:55PM (#4411642) Homepage
    The minute I saw it on slashdot, just like the last time, I knew people would go into the "this is just impossible" mode without at least giving it a shot.

    Ok, I'll bite. READ THIS [highliftsystems.com] (warning, it's a pdf file), and once you do, say it again. I'm not saying this paper is wrong, but it's enough information to realize that there's no one thing preventing it form happening. Not even money, as it would all cost about the same as the International Space Station. The one thing that doesn't exist as of yet is the nanotube wire, which feasbility is clearly only a matter of time. So if the existance of the Space Elevator depends on the existance of a 90,000 Km long nanotube wire (the fabric industry is used to threads this long, again, read the paper), then there's no doubt that it will become a reality.

    The space elevator is doing for me what the apollo program did for my parent's genration: It's giving me an overdose of inspiration.
    • I hear you. I got the same feeling from reading Clarke's book when I was 12.

      And of course, in the age of instant gratification, I want it now!

    • Re:I knew it (Score:2, Insightful)

      by rworne (538610)
      The minute I saw it on slashdot, just like the last time, I knew people would go into the "this is just impossible" mode without at least giving it a shot.
      Considering all the bullshit [alaska.net] these "people" believe [badastronomy.com] on a daily basis [parascope.com], I would not doubt that at all.
    • It inspires me also. Good post.

      Some people worry about terrorists attacks but that shouldn't stop us from building it.

      In fact, if done correctly as an multi national effort, with Russia, China, etc, an attack on the elevator would be an attack on all nations involved.

      Besides, screw the mile high club and start working on the zero-g club!
    • Re:I knew it (Score:5, Insightful)

      by David Roundy (34889) on Tuesday October 08, 2002 @04:27PM (#4412288) Homepage
      Ok, I'll bite. READ THIS [highliftsystems.com] (warning, it's a pdf file), and once you do, say it again.

      This is just impossible! :)

      But seriously, I did read it. Well, really just the section about nanotubes, and if the rest of the paper is equally fallacious, I think that would serve as pretty conclusive evidence of the imposibility of the space elevator. Using a combination of an overestimate of the strength of nanotubes with an underestimate of their density, the author uses a strength/mass ratio that is twice as large as the UPPER bound on the strength of nanotubes (which is the ideal strength). In practice the ideal tensile strength is typically many times higher than the yield strength. In case you're wondering, this is based on density functional calculations I performed myself--far better than the crude estimates refered to in the paper. And yes, I did just check his source [sigmaxi.org]. It's a review paper that refers to an extrapolation of a strength based on a strain from a tight-binding molecular dynamics calculation which the authors recommend taking with a grain of salt.

      On the experimental side, noone has yet (to my knowledge) produced a composite based on nanotubes which is actually particularly strong. Even if these composites are developed (and probably eventually nanotube composites will surpas carbon fiber composites), they are guaranteed to pay a major hit in strength/mass due to the mass of the epoxy. Look for more like a factor of two over carbon fiber composites, rather than the factor of 50 or so advertised.

      As mentioned in the paper, the mass of cabling needed is extremely sensitive to the strength/mass ratio. I don't know the relation (since I haven't looked up the Pearson paper), but he mentions that if you diminish the strength/mass ratio by a factor of 50 (using kevlar) from his fictitious nanotube ratio, the mass goes up by about a factor of 100,000. With an overestimate of the strength of nanotubes of at least a factor of two, probably much more, it seems highly unlikely that the cost of the elevator (already estimated to be rather high) will be within reason, and for all I know there may similar "rounding up" going on in the rest of the paper.

  • *ding* (Score:5, Funny)

    by joe_bruin (266648) on Tuesday October 08, 2002 @02:58PM (#4411668) Homepage Journal
    top floor: shoes, ladies ligerie, space. please mind the gap.
  • Does anybody remember a /. article a while back link to this story [newscientist.com] about how carbon nanotubes cannot handle bursts of common, ordinary light?

    Yes, that's right! A standard camera flash will cause carbon nanotubes to explode!

    Check out the link, there's a neat video showing this effect at work.

    I can just see it now, on the front page of the newspaper... Tourist arrested for carrying terrorist device and it's just a FLASH CAMERA!

    Yeah, I'm excited that the technology to do this is just now barely within our reach - but it'll be a while before it's squarely in our grasp.

    • Mod parent up... I do remember that... I'm curious what the destructive power of a large nanotube cable would be, especially since the small ones created visible explosions (not large, but visible).

      It's almost as much fun to ponder as what would happen if the cable snapped and fell ala Kim Stanley Robinson's Mars trilogy.
    • i can't imagine it would be too dificult to surround the carbon nanotubes with an opaque sheath. i mean, really. I doubt they would build a structure that would explode if you took a picture of it, especially when you consider things like, oh, i dunno, lightning.
  • Doubt it (Score:2, Interesting)

    by geek (5680)
    I watched someone talk about their plans for doing just this on TV about a month ago. I can't remember what show exactly.

    Basically it was a ribbon that started somewhere in the Pacific on some island and went straight up into space attached to an anchor. The ribbon was paper thin but wide and incredibly strong. The reason for it being thin was because of wind resistence which is a major factor especially when its an area with tropical storms. It also had to be a no fly zone since if a plane clipped it, either the ribbon would go or the plane would be cut in half.

    It sounded all well and good but the price was hefty and implimenting it sounds near impossible. It would save us a lot of money in the long run considering how much space shuttle launches cost. I just can't see it being reliable. You wouldn't catch me riding on it, thats for sure.

    One thing I do know, if they get it to work then it'll be one of the greatest engineering feats ever. I hope they can do it, but I doubt they will.
  • Nah... (Score:5, Funny)

    by McCart42 (207315) on Tuesday October 08, 2002 @03:06PM (#4411719) Homepage
    Sounds like more of a Shelbyville idea...
  • by brandido (612020) on Tuesday October 08, 2002 @03:07PM (#4411725) Homepage Journal
    One of the things that I find interesting about the whole process of the Space Elevator principle is the idea that after the first one, it is possible to relatively easily spawn of daughter cables, so that if the first one took 2.5 years, subsequent ones would take less than a year. Not only does this provide for additional capacity, it raises the possibility of selling cables! It also makes the first entrant into the Space Elevator arena almost automatically dominant.

    Additionally, you can create a daughter cable, and then use the cable to sling the entire daughter cable to the red planet - suddenly, we have a means to get to Geo Earth orbit, a way to sling stuff to Mars (using the cable) and a way to get down to the surface of Mars, and back up! This is probably the most feasible way that I have heard of to explore Mars.
  • Hmm (Score:5, Interesting)

    by ShooterNeo (555040) on Tuesday October 08, 2002 @03:08PM (#4411731)
    Couple of points :

    There are obviously enormous difficulties with building this cable, with having it survive lightning strikes, deliberate damage ( could a single guided rocket with an armor piercing molten jet warhead destroy this wire in one hit? If that happened, wouldn't the $10,000 missile have caused 50 billion worth of damage or more...everyone knows that a project like this is going to cost 10 times the current estimate), the mechanical wear as the spacecraft slowly claw there way up...

    A far simpler and cheaper solution is a massive ground based laser array. (which incidentally is how they are proposing to power this thing...why not skip the cable and build a much bigger laser). The beam would vaporize propellant attached to the bottom of the spacecraft, eliminating perhaps 90% of the danger of rocket travel (the rocket blowing up has always been the biggest risk...if it uses a nonvolatile, inert propellant) and reducing the cost to a tiny fraction of current expenses.

    Since the laser system would be a large array, it would not have to be built to nearly the quality standards that a manned spacecraft has to be constructed to since if one of the lasers burns out, blows up, ect the rest of the system picks up the slack.
  • For example, the base tower would have to be 31 miles high, according to this article [howstuffworks.com]. Which is 90 times higher than the current tallest structure on earth, the CN Tower in Toronto, Canada is only 1/3 of a mile (about 170 stories) high.

    There is also talk about using carbon nanotubes [techtv.com] to make up the cable. The pricetag, 40 billion dollars (see 2nd link).
  • Short term option (Score:4, Informative)

    by alwayslurking (555708) <jason.boissiere@g m a i l . com> on Tuesday October 08, 2002 @03:16PM (#4411801)
    You don't need to tether the end, you can still get some very healthy benefits with a partial elevator. Deals with a lot of the security issues too. Cargo craft only need to fly to the low end and ride the rotation to the top where they can slingshot off. Using the Earth's magnetic field and solar power means it's self-stabilising too. More detail and better writing at; Free David Brin Short Story [orbit6.com]
  • it will be much easier for NASA to make fake photos of future "moon missions."
  • by Zathrus (232140) on Tuesday October 08, 2002 @03:18PM (#4411827) Homepage
    Ok, as much as we all laugh at Lance, or whatever his name is, from N'Sync trying to go into space, I think it was moronic of everyone involved not to make sure this happened, that he got up there and back safely, and had one hell of a good time.

    The entire space program has been gradually fading from world view, and particularly from the Western world. Yes, there are programs still going on at NASA and ESA and even in China, but it's nowhere near what was hoped for in the 1960s and 70s. Putting a high profile celebrity into space would bring a lot of attention back to the space program. Would it be fleeting? Of course. That's what media attention is nowadays. But it would probably enspire a lot young kids to go to space, just as the early US and Soviet astro/cosmonauts did nearly half a century ago.
  • With a development like this, we could shoot entire boy bands into space and make the world a better place.

    To the author: are you channeling the Rice University Marching Owl Band [rice.edu] today? We just performed a show [rice.edu] in which we advocated the launching of boy bands into space. Is this a great-minds-think-alike thing, or did you spend some time at Reliant Stadium this weekend? :)

  • uh oh... (Score:2, Funny)

    by pitc (557530)
    hopefully venus doesn't think we're trying to mate...
  • by Tsar (536185) on Tuesday October 08, 2002 @03:28PM (#4411893) Homepage Journal
    Think of the space elevator structure as a 100,000-km-long highway that will require ongoing maintenance and repair," says Smitherman.

    How unrealistic can an analogy be? If a crack forms in some remote stretch of interstate, there's no danger of the rest of the interstate system suddenly ripping away and falling into space. Repairs would have to happen instantaneously without ever breaking an almost unimaginable ribbon tension. And this wouldn't be a very rare occurrence, either, as the ribbon would present a surface area of five to eleven million square meters on each side (5 to 11.5 cm wide, 10^8 meters long). And remember that it's on the equator, which every piece of orbiting debris crosses twice during each orbit.

    And the only mentioned solution for lightning strikes (one of which could be fatal to the ribbon) seems almost totally unworkable, and doesn't take into account that a 100,000-kilometer-high conductive tower would generate its own lightning. Remember the ill-fated (but educational) Space Tether Experiment [nasa.gov]? And the tether was only a mile long. A space elevator's ribbon would intersect a huge chord of Earth's magnetic field, including both Van Allen Belts. Seems to me that, even if the ribbon didn't immediately blow like a giant flash-bulb filament, you still couldn't get within a hundred yards of the base due to the continuous electrical discharge.

    Don't get me wrong--I've dreamed about space elevators since I was a kid reading about Clarke's hyperfilaments, but the more I think about it, the more unworkable it seems.
    • by breadbot (147896) on Tuesday October 08, 2002 @04:12PM (#4412184) Homepage
      For answers to all these problems, see this paper [highliftsystems.com]. In short:
      • Yes, a crack across the ribbon would be bad. But you can make the ribbon be several loosely-coupled parallel sub-ribbons that give a little but don't separate completely when one of them breaks. And yes, you'd have to repair it pretty quickly. At altitudes with lots of space debris, you can make it extra-wide and extra-strong for redundancy, and add only a fraction of a percent to the mass of the overall cable.
      • Lightning strikes can be avoided by going to the right place on the surface of the earth. Parts of the equatorial Pacific receive lightning strikes less than once every few years. And a mobile base station could move the bottom of the cable out of the way of small storms. There are also possible lightning rod approaches for typical storm altitudes (weather balloons, for instance).
      • Shorting out the ionosphere -- given the sheer length of the tether, even if it were as conductive as gold, the resistance between the ionosphere and ground of tens to hundreds of thousands of ohms.

      So yes, there are many challenges to overcome, but they all, fortunately, seem surmountable.

  • by DaytonCIM (100144) on Tuesday October 08, 2002 @03:41PM (#4411986) Homepage Journal
    Instead of spending billions to perfect a safe, efficient delivery method why not just unravel the world's largest rubber band ball [recordball.com]; tie them all together; and shoot the boy bands (one at a time for greater distance) into space?
  • by Pauli (72610) on Tuesday October 08, 2002 @03:43PM (#4412003)
    One thing I never see mentioned by all these proponents of nanotubes as a structural material is that extrapolating the strength of nano-scale covalent bonds to macroscopic dimensions is overly optimistic. "Calculations suggest... based on flexibility... 100x as strong as steel" sure. There are all sorts of materials, if you remove all the defects on an atomic scale, that are super strong. But saying that it is inevitable that we can scale up something from 1 micrometer to 100,000 kilometers is a bit of a stretch. If you made the cable out of solid flawless diamond, it would be stronger than out of nanotubes, and we can already make bigger diamonds than we can make nanotubes. I think a space elevator would be great, but don't hold your breath. There are a lot of details to be worked out in the materials science area before it is really a possibility. But nanotubes do hold promise, just not as much as everyone here seems to think.
  • .. and get on board with my idea for space rubberband.

    Inspired by RoadRunner cartoons and a 6 pack of beer, I was able to sketch out a design that would launch anything we wanted into space without fear of terrorist attack.

    1) Dig hole 2 miles deep.
    2) Build giant rubberband
    3) Stretch giant rubberband over hole
    4) Put cargo on top of rubber band.
    5) Tie Star jones to rubber band
    6) Drop Big Mac in hole
    7) Jones drops. At the low point, right when the rubber band stops stretching, special release latch disengages Star Jones from rubber band thus saving Star Jones for next launch.
    8) Cargo goes shooting up into space
    9) Star Jones eats Big Mac making increasing thrust for next launch.

    Yeah, I know I know.. after a few launches I would have to switch it up with KFC, Taco Bell and BK.

    [Sadly, a coworker had to help me with the physics]

    Anyone know the email to Nasa so I can get them working on this?
  • Energy (Score:3, Insightful)

    by MindStalker (22827) <`moc.liamg' `ta' `reklatsdnim'> on Tuesday October 08, 2002 @04:30PM (#4412305) Journal
    One of the papers on their talks about the high about of energy a climber will require and how the energy should be transmitted by laser (as nanotubes are very good conductors the resistance over that huge distance is just too much). Anyways there is absolutly no talk about conserving energy. As technically if you had a climber at the top, and assuming it used some sort of rollers to climb up and down. The energy generated by the rollers on the way down should be the same energy required to get back up. (Minues electrical resistance and stuff) Is there any way to save this huge about of energy? It seems such a waist to not atleast try.

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