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Space

Space Elevators Could Be Lethal 428

Posted by kdawson
from the fried-by-van-allen dept.
Maggie McKee writes, "A new study reports that passengers on space elevators of current design could be killed by radiation. Even traveling at 200 kilometers per hour, passengers would spend several days in the Van Allen radiation belts, long enough to kill them." Looks like the elevator scientists will get this one solved before liftoff.
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Space Elevators Could Be Lethal

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  • by Anonymous Coward on Monday November 13, 2006 @03:53PM (#16828458)
    will tinfoil hats help?
  • Aqua viva (Score:5, Interesting)

    by TheSHAD0W (258774) on Monday November 13, 2006 @03:56PM (#16828502) Homepage
    One of the most popular (and massive) items that will need to be shipped to orbit will be water; and water makes a good shield against radiation. Just make your passenger cars with a living unit inside a larger freight unit, and fill the gap in between with water. If you used filtered fresh water you could even have windows on both walls and be able to look through.
    • Re:Aqua viva (Score:4, Insightful)

      by quizzicus (891184) <johnbanderson@NOSPAm.gmail.com> on Monday November 13, 2006 @04:26PM (#16829116) Journal
      But how do you avoid the radiation on the way back down? Free fall?
      • by TheSHAD0W (258774)
        Good point. Metals that have been solar-refined from asteroids, perhaps?

        'Course that'll tend to block the windows.

        Unless we start making transparent aluminum in space. ;-)
      • by stungod (137601)
        "On the way back down?" What's that supposed to mean? I can't stay there?

        I'll just take my water and my covered wagon and settle up there...you guys can cook on the return trip if you like. I'll be busy testing zero-G alcohol abuse.
      • by HolyCrapSCOsux (700114) on Monday November 13, 2006 @05:16PM (#16830000)
        While it is up there, the water will be processed through the humans. The water used in the trip down will have a nice soothing yellowish tint.
      • Re: (Score:3, Interesting)

        by meringuoid (568297)
        But how do you avoid the radiation on the way back down? Free fall?

        Sure, why not? It worked for Apollo. The expensive part of a spaceflight is liftoff, and that's where a space elevator really helps. Even if you've got to bring along a capsule to come home, you've still saved the costs of a Bloody Huge Rocket to get to orbit in the first place.

  • by Dogun (7502)
    because we're going to build a 150,000 mile long cable, tethered securely to the Earth's surface...
    • Re:Yeah... (Score:5, Insightful)

      by COMON$ (806135) * on Monday November 13, 2006 @04:40PM (#16829364) Journal
      Never underestimate the arrogance of man. Even if we didn't need the tether, we would still create it because we could. So your statement will join a long line of comments through history.

      "Yeah - Like China will build a 4000 mile long wall."

      "Yeah - We are going to build a tunnel under the English Channel."

      "Yeah - We are going to dig a ditch to let boats cross America."

      "Yeah - The Egyptians are going to build a gigantic pyramid that will still be standing in 4500 years."

      "Yeah - We will propel a highly explosive cargo ship to the moon carrying people."

      • Re: (Score:3, Funny)

        by dsginter (104154)
        You forgot:

        "Yeah - And I'm a Chinese jet pilot."
      • Re: (Score:3, Insightful)

        Reading that, I realize we're all insane. Quite insane.
      • Re: (Score:3, Insightful)

        by snarkth (1002832)
        "Yeah - We will propel a highly explosive cargo ship to the moon carrying people." ... "and bring them back safely to earth"... which was the hardest part.

          snarkd
    • by Mindwarp (15738)
      I prefer to interpret that statement as "...because we're going to build a 150,000 mile long cable tehtered securely to the Earth's surface, but won't be able to work out how to shield the contents from radiation?"
  • Oh, the horror! (Score:4, Insightful)

    by Vraylle (610820) on Monday November 13, 2006 @03:57PM (#16828520) Homepage
    From TA: "it's going to make things a little more complicated and a little more expensive"

    Everybody panic! Apparently, "a little more expensive" == "potentially lethal"!

    I guess people should buy from Wal Mart instead of Target, since the latter is "a little more expensive". Obviously making a purchase at Target will kill you. I love sensationalist headlines.
    • by bcat24 (914105)
      Word. I just wish I had mod points for you right now.
    • Re: (Score:2, Insightful)

      A new study reports that passengers on space elevators of current design could be killed by radiation. Even traveling at 200 kilometers per hour, passengers would spend several days in the Van Allen radiation belts, long enough to kill them."

      Potentially lethal because of the radiation, which in turn makes it a little more expensive. NOT potentially lethal because its a little more expensive.

      I really hope you were trolling

    • Re: (Score:3, Insightful)

      by Smidge204 (605297)
      I like how you quote the LAST line of the article - the part that talks about solution discussions - completely out of context and then complain about sensationalist headlines.

      The full, in-context quote is: "I'm confident that we can solve it," Jorgensen says of the radiation problem, "but it's going to make things a little more complicated and a little more expensive."

      =Smidge=
    • Its already probably a trillion dollars give or take an order of magnitude -- what is another 2%? (But don't worry, kids, after we have it we'll find a way to get a trillion dollars out of it! I mean, we could sell tickets to the space hotel for like a billion dollars each! Then we'd only need to find a thousand sucker billionaires and a space hotel!)
      • by Jeremi (14640) on Monday November 13, 2006 @06:34PM (#16831208) Homepage
        But don't worry, kids, after we have it we'll find a way to get a trillion dollars out of it!


        Actually, unlike other get-rich-in-space-schemes like tourism, a Space Elevator would be a major revenue generator, and not just a novelty. With the ability to safely lift tons of material into space on a daily basis, a lot of industries would become viable: mining, solar power satellites, regular interplanetary travel, zero-gravity factories, non-trivial space stations, etc. Oh yeah, tourism too.


        Space right now is like the Wild West before the invention of the train. You can send a few people out there, sure, but it'll never really be settled in any non-trivial way until there is a bulk-shipping infrastructure in place.

  • Seems like this would be simple to solve. Shield the passenger cabin. The extra weight of the shielding doesn't make a damn bit of difference if it costs a penny for a quintilliton of cargo to orbit. Plus, you get to re-use the shielding. Those passenger cars to orbit are going to be like victorian rail cars. They never wear out.

    • Electronics and a lot of other cargo you might want to send up would be effected by radiation as well. Just saying passenger compartments wouldn't be enough.

      Of course article and Wikipedia all agree that adding complete shielding isn't impossible.
    • Re: (Score:3, Informative)

      by Cadallin (863437)
      The difficulty is that while a space elevator can reduce the cost of moving freight to orbit by a factor of hundred or so (easily enough to be worthwhile) That's still a hugely long way from being "free" like you describe. Even at a cost of $10 to $50 per kilogram (I'm very unsure of the actual speculated values), adding a metric tonne or two of shielding would still increase the cost to get people people (and non-rad resistant items) into orbit immensely. This is why a space elevator, while still a very
  • Haven't RTFA yet, but if mass is not the huge problem it is with rockets, maybe surround the passengers with a meter of water, or whatever it takes. If coming down is faster, for instance in capsules instead of crawling down the space elevator, or if down capsules are faster than up capsules, maybe the water could be cargo for the orbital endpoint of the space elevator.

    Now I will go RTFA.
  • ya think? (Score:5, Insightful)

    by Phroggy (441) * <slashdot3NO@SPAMphroggy.com> on Monday November 13, 2006 @03:58PM (#16828564) Homepage
    I thought the main idea was to send equipment, not people? If we can get one in place (which doesn't seem particularly likely any time soon), it'd be far cheaper to send tons of heavy stuff into orbit via a tether than via a rocket.
    • I would think that it would be cheaper to use rail gun technology to send raw materials into orbit. I hope that we can send automated factories into orbit to collect the raw materials and assemble them into products such as communication satellites and solar collectors. If the elevator is made out of carbon nanotubes maybe it could also be a room temperature super conductor and than we could transport huge amounts of energy from the solar collectors we have in orbit.
    • If we want to do anything serious in space, we'll need to haul lots of cargo up there, but we don't actually need that many workers if they can stay for a while. So if there isn't an easy way to deal with radiation shielding in the Van Allen belts, send the people up on expensive rocket busses, and use the cheap elevators for all the construction material, fuel, and supplies they need.

      And the downward trip is easy - drop capsules with parachutes are a lot simpler and more reliable than fancier rockets like

  • by cliffiecee (136220) on Monday November 13, 2006 @03:59PM (#16828576) Homepage Journal
    This is why the First Amendment is so important- to expose Corporate Greed! Greed which led space elevator manufacturers to produce elevators without the neccesary safety precautions. How many people have to DIE in the name of profit? How long will it be before space elevator travel is actually made safe? It should have been done BEFORE the elevators were even built, damnit!!

    Thank you Maggie McKee, for planting a seed for the grassroots "Space Elevator Safety" movement!!
    • Agreed! We will immediate create a large government bureaucracy, the Federal Elevator Administration, whose job it is to verify that elevators are safe--whether they are taking you between floors or to orbit. All local elevator inspectors will be drafted into the new Federal Elevator Administration and be given jackets with 'FEA' in big letters on the back.
  • This is something I would have thought that the builders would have figured out. Also would it really be that bad? In the first place, I would think that the transport vehicle would be pretty darn fast at that point. Gravity would be less and the thing would gradually speed up as it neared the top. P.S. Why wasn't this a main article?
    • by timeOday (582209)
      This is something I would have thought that the builders would have figured out.
      Since space elevators don't actually exist, I'm not even sure what it means to say they need better radiation shielding.
  • Rockets? (Score:5, Interesting)

    by Odin_Tiger (585113) on Monday November 13, 2006 @04:00PM (#16828600) Journal
    How much thrust would a rocket need to zip you through those sections if you waited to fire it until reaching, say, 500 - 800km? Surely by then you'd be far enough away from Earth that a little bit of push would go a long ways, compared to firing a rocket from the ground?
    • Re:Rockets? (Score:5, Funny)

      by plover (150551) * on Monday November 13, 2006 @04:15PM (#16828878) Homepage Journal
      How much thrust would a rocket need to zip you through those sections if you waited to fire it until reaching, say, 500 - 800km?

      How much thrust could a rocket thruster thrust if a rocket thruster could thrust rockets?

    • While there might be some small benefit, it would not be as large as you think. Gravitational acceleration is still very significant at 500km up.

      Acceleration toward an object due to gravity is given by g = GM/r^2, where G = 6.67e-11 is the gravitational constant, M is the mass of the object, and r is the distance from the center of mass of the object. The mass of the earth is about 5.97e24 kilograms, and its mean radius is about 6.37e6 meters. Thus, the acceleration due to gravity at the planet's surface is
  • I'm a little suprised I haven't heard about this before. Has this been widely known among the space elevator set before now? My experience with space elevators has mostly been through the gloss-over-the-problems world of scifi. I thought the only real problem was in the construction and maintenance, not in the actual use once it's constructed.
    • by Zerth (26112)
      In most of the scenarios I've seen, it is taken as a given that you'd have a tank of water jacketing every passenger container, since water and food would be our primary exports(by weight).

      As for going down, if we've started mining the asteroids, it'd make sense to replace the water tank/jacket with one of ore, instead of crashlanding the ore in the ocean. Alternately, until we ship up water-reclamation facilities, they could send wastewater back.
  • I've always wanted to be the human torch so sign me up!
    Lack of caffine has rendered me unable to come up with other Van Allen refs from SF etc ...
    Anyone?
  • The two rubs (Score:5, Informative)

    by LotsOfPhil (982823) on Monday November 13, 2006 @04:05PM (#16828702)
    This hasn't been an issue before because most astronauts don't get in the way of the van Allen belts. The Apollo astronauts went through super fast (escape velocity is 40,000 km/hr).
    "For a space elevator travelling at the current proposed speed of 200 kilometres per hour, however, passengers might spend half a week in the belts. That would hit them with 200 times the radiation experienced by the Apollo astronauts."

    The article says that you may not want to add shielding because of the added mass. Wikipedia [wikipedia.org] says that "an object satellite shielded by 3 mm of aluminum will receive about 2500 rem (25 Sv) per year." I don't know how this would translate for people going through the area, but 3 mm of aluminum doesn't weigh much.
    • Re:The two rubs (Score:4, Informative)

      by InterGuru (50986) <[moc.urugretni] [ta] [dhj]> on Monday November 13, 2006 @04:36PM (#16829296) Homepage
      2500 rem a year is about 6.8 rem/day. While occupational regulations are complex and depend on what type of radiation, they are the equivalent of 5 rem/year. See [state.ny.us] as an example. This means the occupants could not spend too much time in the Van Allen Belt.
      • Re: (Score:3, Informative)

        by Compholio (770966)

        While occupational regulations are complex and depend on what type of radiation, they are the equivalent of 5 rem/year.

        Either your information is out of date or is for a specific state (in which case it is trumped by the federal limit). The federal limit is 100 mrem (1 mSev) per year [anl.gov] (not the actual legislation but references the federal limit, I believe the number was last changed in 1998). If you know anything about radiation then you know that the federally imposed limit is absolutely ridiculous, it i

  • Plenty of time (Score:3, Insightful)

    by jfengel (409917) on Monday November 13, 2006 @04:18PM (#16828944) Homepage Journal
    Looks like the elevator scientists will get this one solved before liftoff.

    You betcha they will. Compared to the problem of running a cable tens of thousands of miles straight up, and strong enough not to tear under its own weight, this sounds downright trivial. We're still a dozen orders of magnitude off.
  • Would it be possible to really fast through the belts?
  • by nsayer (86181) * <nsayer&kfu,com> on Monday November 13, 2006 @04:20PM (#16828982) Homepage
    Space elevators can be lethal

    So can regular ones [timesonline.co.uk]. Your point?

  • In the same vein -- Always wondered how you'd pass an environmental "impact" review for one of these things. What happens when your 20,000 nmi long cable to geosynch breaks -- or is intentionally damaged by the "bad guys" -- halfway up and 10,000 nmi of cable falls down to earth-- a cable 10,000 nmi would stretch from the coast of Ecuador to somewhere on the island of Borneo.... even bigger mess if it falls over land...
  • by MrScience (126570) on Monday November 13, 2006 @04:22PM (#16829022) Homepage
    The solution, of course, is more speed! With a mass driver [wikipedia.org], and 1000+ Gs acceleration, you too can zip right through that hazardous Van Allen belt in record time!
  • C'mon, COMMON SENSE! (Score:2, Interesting)

    by ShooterNeo (555040)
    Why do people even waste their time on this idea. WHY DO WE NEED SPACE ELEVATORS?

    For all the engineers here: why would you want to build a cable tens of thousands of miles long out of currently UNAVAILABLE materials (unobtanium) to slowly ratchet up one payload at a time? It's a horrid idea, and it STILL takes just as much actual energy to put anything in orbit...just it does so pathetically slowly.

    The plan is to use PHOTOVOLTAIC PANELS to receive the energy being beamed from the ground. That is a pathet
    • Re: (Score:3, Interesting)

      by TheSHAD0W (258774)
      Blasting something up with lasers is less expensive than using mechanical coupling. Though I agree, putting solar panels on the cars to power them is sort of silly. I'd run parallel rails up the beanstalk and let the cars tap the electricity.

      There's something else you've overlooked: A car coming DOWN can use regenerative braking and feed power INTO the rails. If we're going to be mining for metals in space, we might wind up generating more electricity from the cars coming down than we'd spend in bringin
      • by naoursla (99850)
        Nothing comes down the space elevator. Several payloads go up at the same time. Once the vehicle reaches the top, it becomes part of the anchor.
        • by TheSHAD0W (258774)
          While it's under construction, yes; but once it had sufficient ballast mass, you don't think it wouldn't be utilized if the opportunity were there, do you?
        • Stuff had damn well better come down the cable, or the thing will deorbit itself. Angular momentum isn't free, and the outbound payload gains it by leeching it off the cable. Downbound payloads, however, give up their angular momentum to the cable. One of the tricks of the whole idea is to pretty much balance mass going up with mass going down, so as to minimize the amount of extra "station keeping" thrust you have to apply to the cable.
          • by Jeremi (14640) on Monday November 13, 2006 @06:53PM (#16831466) Homepage
            Stuff had damn well better come down the cable, or the thing will deorbit itself.


            I don't think you've thought it through. Of course angular momentum isn't free, but that doesn't mean that you have to send things down the cable to keep the elevator from deorbiting. Once a unit of payload mass is lifted past the center of gravity of the cable, it effectively becomes part of the counterweight, increasing the amount of mass the space elevator is capable of lifting from then on (up to the point where the increased tension would cause the cable to snap, anyway).


            So where does the "non-free" angular momentum come from? From the angular momentum of the Earth, of course... every time something goes up the elevator, the Earth spins a tiny bit slower -- similar to how an ice skater spins more slowly after she extends her arms. Fortunately, the Earth is massive enough compared to us humans that we'd never conceivably make a noticeable dent in Earth's momentum reserves (famous last words? ;^))


            That said, a second parallel "down" elevator near the "up" elevator might be useful at some point, for more efficient round trips. But that's for later, the first task is to get a one-way elevator working.

      • That's the whole point. IF the elevator cable EVER fails : and don't kid yourself, ONE missile strike...not even a nuclear missile, something like a long range cruise missile with a payload of shaped HE, and the entire investment is lost.

        And that's just deliberate sabotage or attack : accidental losses could cut the cable at any time. Once it's cut, we start over.

        My proposed array of lasers on the ground, working in parallel (there would be a _LOT_ of them, at least 10,000 separately powered and housed la
    • Re: (Score:3, Insightful)

      by painandgreed (692585)

      Why would we research unavailable materials? To make those materials obtainable. After they are obtained and the structure built, most of what you are bitching about will be trivial. You don't beam power up to the transport module. You have a power generator in deep space where it is free and plentyful and then you send it back down the cable to the surface where it can power cities. Along the way, the transport module can tap into that and use it for a constant acceleration for a realativly speedy ride up

    • by roystgnr (4015) <roystgnr@nOspAm.ticam.utexas.edu> on Monday November 13, 2006 @06:06PM (#16830790) Homepage
      It's a horrid idea, and it STILL takes just as much actual energy to put anything in orbit...

      No, it doesn't. Most of the energy used by a rocket goes into the exhaust's temperature and velocity, not into the payload's velocity. Better yet, much of the energy that goes into a space elevator payload comes from the Earth's angular momentum, not from the beamed power source.

      You're right that laser launch may be a good idea, and you're right that the materials necessary to build a geosynchronous tether on Earth do not exist in bulk and may never be good enough... but there's obviously still a gap between the amount of passion you've spent learning about both subjects and the amount you spend speaking about them. Calm down, take a deep breath, and back slowly away from the Caps Lock key...
  • by StikyPad (445176) on Monday November 13, 2006 @04:32PM (#16829232) Homepage
    Additionally, the space elevator is expected to be very tall, taking riders several miles above the surface of the earth where, experts say, they could fall to a harrowing death. And if that's not bad enough -- it turns out that if the earth were to suddenly stop spinning, the entire space elevator could come crashing back down to the ground!!! I, for one, will from now on refer to them only as "Space Elevators of Death!" in order to raise awareness about this potentially leathal issue!
  • Hybrid solution (Score:4, Informative)

    by Fonce (635723) <msmunter AT gmail DOT com> on Monday November 13, 2006 @04:40PM (#16829366) Homepage
    Given that gravity won't be nearly as much of an issue at that altitude, a combination of shielding including water or metal (likely both) and increased speed seems to me to be the simplest route. All things being equal, that's probably the better solution.

    We've made it through the Van Allens before, we'll figure out how to do it again.

    And, anything can kill you, really, so long as it's an action. Space elevators aren't lethal in and of themselves. Organ failure due to blunt trauma, rapid depressurization, radiation poisoning; these can kill you. An elevator cannot. It's an inanimate object. Well, unless you're on acid. Then you're on your own, kid.
  • This is the same crap that astronauts have to deal with, nothing more.

    Yes, radiation is OCCASIONALLY an issue, when the sun starts to get excited, so you have a shielded area that you restrict movement to when that happens. The sun telegraphs it's bad moves, generally giving us more than enough time to get to shelter. It is what they do on every Space Station ever created, and there is no reason they could not do the same on the elevator.

  • Look - it aint rocket surgery is it?

    Question: will passing through van allen belts without shielding cause harm to humans?
    Answer: Yes.

    Next time you need a stupid answer to a stupid question, I'll provide it free!

    I simply can't understand why this would be news of ANY type! I mean, come ON - if it wasn't DEAD OBVIOUS, what would be?

    So, the solution is to ensure that humans travel inside a tank, which is surrounded by 50cm of water, or 30 cm of polyethylene.

    BIG HAIRY DEAL!

    1) Take clean water UP.
    2) Bring dirty
  • by Microsift (223381) on Monday November 13, 2006 @05:22PM (#16830096)
    Everyone knows exposure to this radiation is nearly always benign...in fact, 75% of the people exposed to this radiation found it to be beneficial. The remaining 25% were less pleased, apparently having super-strength and near invulnerability does not make up for the fact that one's body is covered with rocks and people call you a "Thing."
  • by Dr. Zowie (109983) <slashdot@@@deforest...org> on Monday November 13, 2006 @06:34PM (#16831220)
    Ionizing radiation is just awful on chemical bonds and crystal structures. After all, it works by knocking electrons or whole atoms loose from the nice, bound states they were in. That's how the radiation damages you, too -- it's just that biological systems are a whole lot more sensitive to being scrambled, than are bulk objects like bricks or (to pick a not-so-random example) bundles of carbon nanotubes.

    High doses of radiation do strange things to materials -- increase cross-links, damage coherent structure, add skillions of crystal defects. If you lower a nice flexible, white piece of polyethelene plastic into a nuclear reactor for a while, you are liable to pull out a yellow, harder, brittle, fragile piece that has the same overall shape.

    If I understand the nature of the space elevator right, each particle "hit" would tear apart a carbon nanotube, gradually shortening the average tube length and weakening the whole bulk structure. I'm sure someone has thought of this effect, but we haven't seen much of it in the space elevator press packets.
  • by Doc Ruby (173196) on Monday November 13, 2006 @06:44PM (#16831374) Homepage Journal
    Why would I travel at only 200KPH? How about 2000Km:h, on an engineered track, through the near-vacuum past 100-200Km out? Space is an acceleration game, so really I'm concerned only with how long I have to spend under the crush. At 1G, I could get to 2Mm:h (Megameters per hour) in under 1 minute. 15 minutes through the atmosphere, another minute up to 2Mm:h, then a couple of hours to the top (another 1.5G deceleration for a minute) once friction is immaterial. At 1.5G all the way up halfway, then slowing 1.5G the rest of the way, that's 2 minutes [cthreepo.com] to the top. I don't know if I'd want to fry on a daily commute, but why live with Earth limits when we're leaving the Earth?

    The other solution they're not considering in that article is to engineer the elevator car to travel inside the cable, rather than outside. Use the mass necessary for tensile strength for radiation shielding, too.

    These are 30 second solutions. I'm sure the next decades before we actually deploy the spacehooks will find lots of better solutions.
  • Killed? (Score:5, Funny)

    by seebs (15766) on Monday November 13, 2006 @06:53PM (#16831470) Homepage
    ... Or given SUPERPOWERS!

    You guys can't fool me, I saw that documentary about those people on the space station. I wanna be the one who can be all stretchy!

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