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Space Technology

Report: Space Elevators Are Feasible 374

Posted by Soulskill
from the i'll-order-a-dozen dept.
Daniel_Stuckey writes "It's the scourge of futurists everywhere: The space elevator can't seem to shake its image as something that's just ridiculous, laughed off as the stuff of sci-fi novels and overactive imaginations. But there are plenty of scientists who take the idea quite seriously, and they're trying to buck that perception. To that end, a diverse group of experts at the behest of the International Academy of Astronautics completed an impressively thorough study this month on whether building a space elevator is doable. Their resulting report, 'Space Elevators: An Assessment of the Technological Feasibility and the Way Forward,' found that, in a nutshell, such a contraption is both totally feasible and a really smart idea. And they laid out a 300-page roadmap detailing how to make it happen."
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Report: Space Elevators Are Feasible

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  • by bigjarom (950328) on Wednesday February 26, 2014 @01:18AM (#46342697) Journal
    For anyone interested in the concept of the space elevator, The Fountains of Paradise (1979 Novel) by Arthur C. Clarke, is a must-read!
    It's a very well-written novel that focuses on many of the technical aspects of building a space elevator.
  • Laughable what? (Score:5, Insightful)

    by Rosco P. Coltrane (209368) on Wednesday February 26, 2014 @01:30AM (#46342741)

    It's the scourge of futurists everywhere: The space elevator can't seem to shake its image as something that's just ridiculous, laughed off as the stuff of sci-fi novels and overactive imaginations.

    I've first heard of space elevators decades ago, and not once have I read or heard anyone saying it's a ridiculous or laughable idea. All I've heard is that it'd be a really great, smart and economical way to access space, if only a strong and light material could be found to prevent the cable from being several miles across in diameter at the base and collapse under its own weight. Where did the story's submitter get that from?

  • by hey! (33014) on Wednesday February 26, 2014 @01:33AM (#46342755) Homepage Journal

    One of the things I don't see discussed much is the potential failure modes for such a system.

    My wife is a physical oceanographer, and one of the failure modes for instruments deployed on cables from a ship is a 'wuzzle' -- a large tangle of steel cable. Given the nature of the stuff, a length of cable that fits nicely in a spool on deck can twist itself into a knot larger than the ship.

    So one thing I'd like to know is what are the potential hazards a couple thousand miles of elevator cable falling to the Earth's surface? Could we end up with tangles miles in diameter?

    I think a space elevator is a great idea if it's feasible, provided that in the criteria for "feasible" we include being prepared for the conceivable ways the project could fail.

    • In the above book, a Martian space elevator fails (more specifically, is induced to fail by the deliberate application of high explosives.) The result is highly destructive. The Martian equator is no longer an imaginary line, but rather a prominent physical feature.

      • by dargaud (518470)
        I've read this excellent book. But the outcome of a failure highly depends on the construction mode. It's more likely that the 'elevator' would look like a thin tape. In case of failure it would be akin to drape falling. No big deal even if there's lots of it, the middle part simply burning up in the atmosphere, the upper part getting in orbit.
      • by cbhacking (979169)

        That is a (one of several, but in my opinion one of the more regrettable) unfortunate failure to do his homework, frankly. The cable he envisioned was hard, durable, dense stuff. That's not what you want, though. The only real criterion is tensile strength, and density is actually the exact opposite of a desirable property. Dense materials (I believe his cable used diamonds, which are notable for hardness more than for tensile strength) simply increase the tension the cable is under, making it harder yet to

    • by asmkm22 (1902712)

      I don't think these elevators would operate like a normal elevator, where you have cables pulling a structure up, so you wouldn't have to worry about a spool of anything getting tangled. Most designs have the structure actually "crawling" up the cable.

    • Given the nature of the stuff, a length of cable that fits nicely in a spool on deck can twist itself into a knot larger than the ship.

      lol that's kind of hilarious

    • by redback (15527)

      In a novel by Frederik Pohl, one of the heechee series, terrorists set off a bomb at the ground terminal of a space elevator and it causes the rope to fall to the ground.

    • Here's a link to the actual report [virginiaedition.com], so enjoy.
    • by dbIII (701233)

      One of the things I don't see discussed much is the potential failure modes for such a system.

      Probably because it's best modelled as a lot of little chunks each with different gravitational force on them and forces from the elements above and below - and that's not trivial if the thing has a break in it somewhere.

      The simplest mode of failure is if the thing is under a huge amount of tension and somebody cuts it off at the base - as in at least one movie. In that case the entire thing flies off into a high

  • What's the tallest thing we could build right now?

    Neal Stephenson and Keith Hjelmstad who is at Arizona State University have looked into this. The thought is to build a structure that reaches the stratosphere and then launch rockets from the top.

    The Tall Tower [asu.edu]

    I have no idea if this is easier or harder then a fulls space elevator. I would guess not as hard. Sadly, the web site has little activity since I firsrt saw it. Still, it's interesting in the context of a space elevator.

  • Nanomaterials are strong and light enough, but the rub is that scientists can't get them to scale yet. Luckily, billions of dollars are being poured into this area of research. The report predictsa suitable material will be ready by the 2020s.

    Materials are the sticking point and they can predict anything they want. Will those predictions come true? We will only know if and when it happens. I think it is doubtful. From what I can find they have made carbon nano tubes about 130cm long. Extending them to 62,000 miles might not be possible.

    Saying something is feasible based on prediction of scientific progress is dubious at best.

  • by nomaddamon (1783058) on Wednesday February 26, 2014 @04:05AM (#46343345)
    Using the elevator for transfer of goods - will work but the goods will get a huge dose of radiation

    Using it for transfer of organic matter (i.e. humans) above LEO is not feasible due to the speed/shielding needed

    The worst part of Van Allen belt is about 19000km wide and starts at around 7000km high. Apollo moon missions passed trough it at roughly 15km/s, spending roughly 2*21 minutes in it.
    The astronauts received roughly 1rem of radiation through 3 layers of thick aluminum radiation shielding.
    That is 1/5 of the yearly the limit in US for people working with radiation.
    At reasonable speed (~200m/s) the elevator would take ~26h to pass through the belt, meaning it would need at least 75x more radiation shielding than Apollo did and that the lift would need 15m thick aluminum honeycomb walls (using 70's technology).

    Even with todays technology the shielding will be way too bulky/heavy for elevators to be viable alternative to rockets for above LEO human transfer.
    • Even with todays technology

      Luckily, by the time we're really ready to build a space elevator, we'll be using tomorrow's technology [bbc.co.uk].

    • Why would the elevator be limited to ~200m/s?

      Once it is out of the atmosphere, there is no drag and over the distance to the Van Allen belt a 1 G acceleration would bring it up to very high speed. There would be plenty of time after leaving the Van Allen belt to slow back down, again with mild acceleration.

      What is it that I'm not seeing here? Would we not use some form of railgun technology to accelerate and decelerate the capsules? We might need a transfer platform above the atmosphere to change from a "

    • by Soralin (2437154) on Wednesday February 26, 2014 @06:45AM (#46343927)

      Simple solution for the Van Allen belts: remove them.

      https://en.wikipedia.org/wiki/... [wikipedia.org]

      High Voltage Orbiting Long Tether, or HiVOLT, is a concept proposed by Russian physicist V.V. Danilov and further refined by Robert P. Hoyt and Robert L. Forward for draining and removing the radiation fields of the Van Allen radiation belts[29] that surround the Earth.[30] A proposed configuration consists of a system of five 100 km long conducting tethers deployed from satellites, and charged to a large voltage. This would cause charged particles that encounter the tethers to have their pitch angle changed, thus over time dissolving the Van Allen belts. Hoyt and Forward's company, Tethers Unlimited, performed a preliminary analysis simulation, and produced a chart depicting a theoretical radiation flux reduction,[31] to less than 1% of current levels within two months[32] using the HiVOLT System.

      If you're going to be building a space elevator, getting rid of the Van Allen belts is a relatively easy task in comparison.

  • A robust system should not totally break because of one point of failure. A single elevator is fragile because any natural (meteorite), man-made (space junk) or intentional (war) cause acting anywhere along the 100'000 km long cable can totally destroy it with dramatic consequences on Earth when parts of the cable impact the surface. The elevator design could be made more resistant by building a network of cables, not a single cable.

    • by cbhacking (979169)

      Sigh... your numbers are wrong, your science is wrong, and your concept is questionable.

      Let's start with the basics: GEO is 35,768 KM from the equator. You need twice that much, at most, ribbon (not cable. Cable is dramatically less feasible and stupid besides). No idea where you got 100,000 KM from...

      Now, about that ribbon. It's a few feet (maybe around one meter) wide at the base, where tension is low. It's several times that at GEO, where tension is highest. It's got a thickness comparable to paper and a

      • by geekoid (135745)

        You post is mostly wrong and stupid.

        ". It's got a thickness comparable to paper"
        What do you base that one? It has to be able to carry an elevator, you know for the space elevator

        " will mostly burn up in the atmosphere"
        Do you even have a clue what cause things to burn up in the atmosphere?

        Why do you ignore the fact that the counter weight is going to fly off, do a figure eight, and the come back to earth?
        When something strike the counter weight, it' will have a different angle of momentum and push it out of

  • by korbulon (2792438) on Wednesday February 26, 2014 @06:22AM (#46343817)
    Main problem I foresee is what happens when someone presses all the buttons.

Some people have a great ambition: to build something that will last, at least until they've finished building it.

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