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Space Science

Expert: Mars Astronauts Would Lose Teeth 323

Posted by Hemos from the i'll-gum-ya-to-death dept.
Ant wrote to us with a story on Discovery about the long term consequences of manned and "womanned" missions to Mars - lots of research about bone-weakening effects of zero G environments, with tooth loss high on the list.
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Expert: Mars Astronauts Would Lose Teeth More

Expert: Mars Astronauts Would Lose Teeth

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  • I've been to the National Air & Space Museum at the Smithsonian. Apparently, you don't need teeth to eat Astronaut Ice Cream and Tang.

    Dancin Santa

  • All I want for christmas is my two front teeth (Score:5, Funny)

    by xted ( 125437 ) on Tuesday August 28, 2001 @12:56AM (#2224247) Homepage
    I say we get all the astronauts to smile for a group picture when they land on mars.

  • Real Url (Score:2, Informative)

    by Talez ( 468021 )
    URL is wroing... Real URL is:

    http://dsc.discovery.com/news/briefs/20010827/ma rs teeth.html

    Do people read the bit which says "Check URLS" anymore?

    Talez
  • Well most space food is in a paste or freeze dried format to boost nutrient intake anyway so it wouldnt matter.

    One would thing the issues with blood polling and muscular atrophy may be more succint on long missions like this, there is a dange that muscles can atrophy very badly with long term exposure to low or zero gravity, this coupled with bone fatigue might mean that an astronaut arriving back on earth after his long trip might just collapse when he is exposed to the earths gravity.

    Astronaut pancake anyone ?
    • Well most space food is in a paste or freeze dried format to boost nutrient intake anyway so it wouldnt matter.
      Not true. At least not any more. I saw it on the Discovery Wings channel. They actually have crunchy cereal and all that good stuff.
      - Hyperbolix

      • Gum anyone? (Score:2, Insightful)

        by M_T_Toaster ( 515319 )
        Wouldn't chewing gum give some protection against this?
        It would give them plenty of exercise to the teeth and jaw muscles, and might well be popular (most astronauts are American now and so presumably like chewing the cud).

        OTOH the gum might also come in handy for fixing things in the ship and or holding things down in zero g

        think of the sponsorship deals... the Wrigley's [wrigley.com] Orbiter etc

  • Have you seen the stuff they eat from those pouches?

  • I think the link is broken (Score:4, Redundant)

    by leucadiadude ( 68989 ) on Tuesday August 28, 2001 @01:01AM (#2224266) Homepage
    It looks like the story link doesn't work. At least it didn't work for me. Here [discovery.com] is the one that worked for me.

  • Not like there's any good restaurants on mars anyway.
  • Here's a working link [discovery.com] to the story.

    I'm now hit with that 'compression filter' problem.... how to get the info out there seems to be the question.... Ah. good. this ramble fixed it.

  • They are already toothless :)

    (just joking, its a fine state, I lived through High School there)

  • The discovery page seems dead. But, going out on a limb -- from what I've read, it seems to take about 6 months to get to mars. There have been more than a few people who've lasted this long in space, and they seemed to have nice smiles when they returned.

    Once on mars, the effects should be mitigated by the gravitational field - right? How much less is mars' gravity compared to earth?

    • Read the story. Among other things, a two-year Mars mission including one year of zero-g (6 months there and 6 months back... that back part is also important) would be enough to cause permanent tooth loss.

      And the story also mentions those same people you cite.


    • Once on mars, the effects should be mitigated by the gravitational field - right? How much less is mars' gravity compared to earth?


      Mars' gravity, compared to Earth's, is 0.38 to that experienced on earth. Now, I have no idea what this means for bone structure as IANADoctor.
  • Realizing that doing something like this would increase the cost by, well, a lot, couldn't the astronauts accelerate at around .5 to 1 G for half the trip (creating gravity), then reverse the spaceship and decelerate (yes, I can't spell, but neither can the Slashdot staff some days).

    You'd need more fuel for this, of course. But it could reduce the problems of microgravity.

    Of course, I could be wrong.
    • Or just create a cylindrical craft with spin. Of course NASA isn't exactly known for thinking outside the box...
      • > Of course NASA isn't exactly known for thinking outside the box...

        Actually, there's a pretty cool idea floating around for sending two craft (one USian and one Russian, IIRC) and tethering them together so that they would rotate around a common center.
    • You wouldn't need much fuel at all if you did the 1G radially.

      The Mars Cork-Screw...roller coaster or NASA mission: You be the judge.

      --
      God I wish slashdot had spellcheck
    • You simply can't carry enough chemical propellants to do things this way. However, if you developed a fusion rocket this might well be practical.

      However, as others have pointed out, simply spinning the ship is by far the easiest and simplest way to get around this issue.

      • Slighltly off topic but here goes:

        I recently read about the vasimr engine, a plasma drive running on helium and elctricity. I was thinking what if we tried to combine a fusion plant (it uses plasma and produces helium exhaust) with the vasimr and we should have a efficient impulse drive (just to throw in som st techno babble)

        I know fusion plants are not yet mature technology :)

    • You're right in that providing artificial gravity is a possibility, but the amount of fuel to accelerate at 9.8 m^2 half way there is huge, and there's not really a reason for doing it like that.

      There are two good alternatives, though, which have been tossed around, and have the same effect, though with very little fuel use. One is to send a cylindrical ship, and spin it about it's axis, so that there is a force pushing the astronauts to the outside walls. Like in 2001.

      That works, but it creates some weird design problems, as far as headroom and living on the walls.

      The other option is to let out a tether with a countermass on the end of it, and then spin around a central point on the tether. With a big enough countermass, or a long enough tether, this works really well, and it's comfortable for the astronauts, as they can stay oriented to the 'floor' of their ship.

      There was originally a plan to put something necessary at the other end of the tether, like fuel for the return trip or something, but it turns out to be much more efficient if you can just put something disposable on it (like one of those big boosters you used to leave Earth). That way you can just pop a bolt when you get to Mars, and don't have to worry about the tether snagging when you try to reel it back in.

      A book that talks a lot about this is Robert Zubrin's "The Case for Mars". He's the president of the Mars Society, and is pretty knowledgeable about this stuff. I highly recommend the book to anyone interested in some of the design challenges, and why we can beat them.

      • That way you can just pop a bolt when you get to Mars,

        Um, what about the return trip? Do we not want gravity for that too? Or have we not planned for the return trip?

        • Once you're in orbit, the rocket engine that lifts you off Mars is expendable. Hence, you get another rope and hook it up for the return trip.

          I should point out that in Zubrin's Mars Direct architecture the habitat that you do the trip there on, and the vehicle you use for Earth return, are two different vehicles, but even if they were one and the same it doesn't pose a major problem.

    • I'm quite sure that in order to create artificial gravity the force or acceleration would have to be pointed in a downward direction in reference to where the astronaut was standing. I don't think that by accelerating the ship to 9.8 m/s^2 we will be able to create artificial gravity but just a thrust force or that launching feeling. Something similar to what happens when you accelerate hard in a car. Plus the amount of fuel that would be required would be enormous and highly expensive.

      But to answer your question, Gravity that we experience on Earth does equal acceleration but it has to be pointed downward or towards the centre of an object to have the same effect that it does on Earth.

    • Acceleration or Spinning, both are hard. (Score:5, Informative)

      by dragons_flight ( 515217 ) on Tuesday August 28, 2001 @02:47AM (#2224461) Homepage
      To give you some idea of how far we are from this. If you could afford the fuel to do 0.5 G to half way and then flip to slow down, the whole trip takes only 2.4 days at Martian closest approach. Ramp it up to 1 G and you get things down to 1.7 days.

      Simulated gravity could be made this way but no engine design has fuel sufficiently light to make this even remotely possible with current technology.

      As far as spinning. Acceleration = Radius * (angular frequency)^2. To get a good one G in a ship with a 5 meter radius, you'd have to spin it at 1.4 revolutions per second. Okay so make the ship bigger and aim for less gravity? 20 meters for 0.5 G still carries a rate of 0.49 rev. per sec. Spinning isn't generally a simple answer unless you are planning something that is monumentally huge. A station 2 km across can get to 0.5 G with one revolution about every 14 seconds. (If you feel like making the stretch to call that simple.)

      Someone might point out that without air resistance or other interactions, getting and keeping a spin isn't the problem it would normally be. This is true, but if the object is small you get all kinds of wierd effects caused by the gradients in force. For instance a 1m tall person standing in that 5 m ship at 1G would have only 80% of the gravity at his feet acting on his head.

      I will concede that getting such a ship spinning takes not unreasonable amounts of energy (considerably less than would presumably be spent getting it to Mars at a reasonable speed, and not a problem if you start the spin while in Earth orbit and fuel is plentiful), but then you pretty much have to go in a straight line along the axis, because you've just made the largest gyroscope man's ever seen, and turning the thing would be a bitch.

      Some of the other problems would include getting in and out of such a ship (think floating through a hatch on the axis and then somehow matching rotation). Also anything on the outer wall would want horribly much to fly off. Large stresses would be involved in getting it spinning and holding it there. And last but not least on my short list, is that any propulsion system would carry both mass and angular momentum away from the ship affecting the rate of rotation.

      Okay, so I've sat down and done the calculations. Sustained acceleration isn't likely to work any time soon. Rotation is technically possible, but certainly not easy given the kind of speed needed and presents serious technical issues to deal with the stresses, manuevering, getting in and out of the ship, etc.

      Good luck NASA, I hope you figure something out in my lifetime.

  • ummm.... (Score:1, Funny)

    by Anonymous Coward
    last i checked, mars had gravity... then again, I haven't been there in a while...


    - god

    • last i checked, mars had gravity... then again, I haven't been there in a while...

      Yes... but if you read the story you might notice that it mentions a mission with one year of zero-g. That's pretty much 6 months out and then 6 months back.

  • Why are we trying to colonize mars when we have the moon soclose? Think about the possibilities.. If raw materials such as iron where to be refined, the cost to transfer the materials would be cheaper because of the short distance.
    Even looking at it from a safety standpoint.. If something were to happen where an evacuation needed to take place, they are that much closer to home. I guess we are just trying to see how far humans can reach into space.

    • Re:shoot for the moon (Score:5, Interesting)

      by Goonie ( 8651 ) <robert.merkel@b[ ... g ['ena' in gap]> on Tuesday August 28, 2001 @02:06AM (#2224411) Homepage
      Why are we trying to colonize mars when we have the moon soclose? Think about the possibilities.. If raw materials such as iron where to be refined, the cost to transfer the materials would be cheaper because of the short distance.

      Because the Moon, in some ways, is actually not closer to us at all, and there are a lot more things worth having on Mars when we get there.

      Firstly, Mars has a day almost identical in length to Earth's. Why is this so important? Because it means you might be able to grow plants there by the natural light. Growing plants under artificial light is very inefficient - the only ones that we can afford to do so for are kind of illegal in many places :) You can't grow plants by natural light on the moon because the two-week night would kill most plants (let alone the problems of your greenhouse heating up to boiling point during the two-week day).

      Secondly, Mars has almost certainly got a lot more water available than the Moon does. The moon has virtually no water available. You can't have a colony without a water supply :)

      Thirdly, just because Mars is further away doesn't mean it's more difficult to get stuff to and from it. The travel time is an important issue for humans, but for cargo it often doesn't matter, and for cargo it takes *less* fuel to land stuff on Mars because you can use the Martian atmosphere to slow down when you get there, unlike the moon where you have to use more fuel slowing down. Going the other way, it's easier to get stuff off the Moon than Mars (because the moon has less gravity), but you can make rocket fuel for your rocket a lot more easily on Mars than you can on the Moon (because if you have water, you can use electrolysis to get hydrogen and oxygen - instant rocket fuel).

      Finally, if you're going to run a self-sustaining colony which pays its own way, to pay for imports from Earth you need something you can export back. From what we know about the composition of the moon, we're fairly sure that there's not much there of value (except for Helium-3, which is a fuel that might be used in fusion power plants in the future but is very difficult to extract), but on Mars there's a distinct possibility of finding high-grade deposits of gold, platinum, and other commercially valuable metals. In addition, if we ever mine the asteroids (many of which are virtually pure precious metal and are thus incredibly valuable), it's much easier to supply the miners with food and supplies from Mars than from the Earth or Moon.

      In any case, we're not really trying to colonize either yet. As to the interest in exploring Mars, we've been to the Moon and have a fairly good idea of what it's like. Mars is the next step along the line.

      Even looking at it from a safety standpoint.. If something were to happen where an evacuation needed to take place, they are that much closer to home. I guess we are just trying to see how far humans can reach into space.

      • Re:shoot for the moon (Score:5, Interesting)

        by Caid Raspa ( 304283 ) on Tuesday August 28, 2001 @04:59AM (#2224602)
        if you're going to run a self-sustaining colony which pays its own way, to pay for imports from Earth you need something you can export back.

        This is the major hazard of space colonization. You have to get money from it, if you want to pay it with corporate money. And you suggest raw materials!!! I firmly believe transport costs of pure platinum from Mars would be high enough to make extraction from sea water look dirt cheap. Recycling is another thing that will not let the prices go that high. Extraction of gold from used electronics will be cheaper than importing the stuff from Mars.

        Information would be cheap to transport, so prodicung it on other planets would be better. For geological/planetological research, every planet will have it's own colony, if robots are not considered better.

        However, I think Moon would be the prime place for some sciences: Astronomers would love the continuous two-week data set. Radio interference from Earth would be no problem on the backside of Moon. No atmosphere means all wavelengths (IR to gamma-rays) can be studied from the Moon. Lower gravity means that the telescopes can be made larger. Some deep craters near the Lunar poles are in permanent shadow, so they would be excellent places for far infrared astronomy, where detectors must be at milliKelvin temperatures. To have a 10-K heat sink nearby will make things very easy.

        Hazardous biotech research could also be done and safely tested on the Moon. It would be much harder to kill billions of people by stupid accidents.

        Another possibility of the Moon is to use coilgun-like launchers that would use solar power to accelerate the cargo. This would eliminate the need for chemical propellant and rockets. Estimated launch price: less than one dollar per kilogram! As launching from Earth will never be able to compete with this, manufacturing satellites etc. could be an interesting option.

        • I firmly believe transport costs of pure platinum from Mars would be high enough to make extraction from sea water look dirt cheap. Recycling is another thing that will not let the prices go that high. Extraction of gold from used electronics will be cheaper than importing the stuff from Mars.

          Okay, but do you have any particular reason to believe this, or is it just a tenet of your faith? If you consider that fuel can be made relatively cheaply from local ingredients (just react some H_2 with the atmosphere, really) and that transport time isn't important for cargo, it might not be too expensive at all. Strap a booster onto your block-o-platinum and loft into Martian orbit (low gravity, so lots easier than for Earth). Fire up an ion/magsail/Vasimir/whatever engine and two years later you're aerobreaking into Earth orbit.

          By far the largest cost to mining on Mars is going to be transporting and supporting the human miners -- which, sadly, makes robots a promising alternative. It'll be interesting to see which gets there first, robots sophisticated enough for autonomous mining operations, or launch costs low enough to realistically support human extraterrestrial colonization.

          • Okay, but do you have any particular reason to believe this, or is it just a tenet of your faith? If you consider that fuel can be made relatively cheaply from local ingredients (just react some H_2 with the atmosphere, really) and that transport time isn't important for cargo, it might not be too expensive at all. Strap a booster onto your block-o-platinum and loft into Martian orbit (low gravity, so lots easier than for Earth).

            You still have to loft the cargo out of the Martian gravity well, and cancel the (very large) gravitational potential energy difference between Mars's orbit and Earth's. This will be about as expensive as launching something into space from Earth - not cheap. Your fuel isn't free. It costs time and effort (read: money) to manufacture, even on Mars.

            There's also no reason to believe that mining on Mars will be cheaper than mining on earth even if you *don't* transport the cargo anywhere. Why would we magically find rich veins of platinum on Mars? It has roughly earth-like composition.

            If you're going to mine anything, then near-earth asteroids are your best bet, and even then, I'm skeptical of asteroid mining being worth the cost. Asteroid composition varies widely enough that you can find ones that are very rich in metal ore.

            IMO, mining the moon for raw mass is probably the most practical operation that will go on in space. To build a space colony, you need a lot of mass just for radiation shielding. Moon dirt works well for that, and is a lot cheaper to loft than material from Earth. If you're building a spinning structure that has mostly tensile forces, then you can get structural material from the moon too (fiberglass cables).

            Mars, on the other hand, has little that would be worth transporting back to Earth. In pretty much all cases, you'd be better off mining or manufacturing it on earth and avoiding transport costs.

            OTOH, Mars is a great site for colonizing and possibly terraforming, once there are enough settlers willing to pay out of pocket for the trip.
      • Also Mars has that giant alien machine underground that heats up the frozen ice core and releases oxygen into the environment within a matter of minutes to create an instant earth-like atmosphere. Does the moon? No way. So we got that going for us.
  • the correct url is http://dsc.discovery.com/news/briefs/20010827/mars teeth.html

    ps. get rid of the horrid 20sec "delay", it's annoying as hell.
  • That's right. Go into space, become old and degrepit. Die young, with no teeth.

    I'd have to say that NASA will need a more effective marketing campeign.

    NASA: So, you want to be an astronaut?

    John DOe: I realize I don't have to worry about the space shuttle blowing up, but I don't want to die young, with no teeth either...

  • Send John Glenn (Score:5, Funny)

    by Swaffs ( 470184 ) <swaff@ERDOSfudo.org minus math_god> on Tuesday August 28, 2001 @01:11AM (#2224305) Homepage
    He probably doesn't have any teeth left anyway.
  • In the old days, explorers ventured into the unknown. If they were very lucky, a third of the original crew returned, crammed into the last ship that wasn't lost in a storm or on an uncharted shallow.

    Those who did make it back had suffered - rotting food, no medical care...Peglegs, eye patches, anyone?

    Here we are hundreds of years later and our explorers are worrying if they can smile for the cameras when they get back. If they can come up with a way to prevent it, great - but don't set a mission back five years to design around teeth!

    I mean...I don't think it's wise to waste men and equipment on a fruitless undertaking, but no new worlds have ever been conquered without a fair amount of casualties. Missing teeth stopping the first landing on another planet (and potentially settling the question of life off our own planet) would be an insult to every great explorer that man has produced.

    We need to grow a backbone if we expect to explore, but we won't...Politics and the media make it impossible. Kind of sucks, doesn't it?
    • As good as this parallel is, there is a substantial inversion going on nowadays. In the old days of exploring, most of the crew were essentially thugs, biomass to keep the ship/sled/canoes going. All the *truly* intellegent people, ignoring the single great explorer on each of these expeditions (grudgingly giving them the benefit of a clue) stayed at home, and didn't have these problems with their fingers rotting off and discovering that fruits really are good for you in moderation. Nowadays we send our absolute best and brightest (or at least the best and brightest we can muster). These folks are precisely the people that wanted to keep their teeth and other extremities in the first place.

      Besides, in the olden days of exploration, most people didn't even start with teeth and all their fingers...

    • Heh.. I mean.. its in the name of adventure and exploration, right? I'm sure NASA would love to hear from guys like yourself.
    • ->In the old days, explorers ventured into the unknown. If they were very lucky, a third of the original crew returned, crammed into the last ship that wasn't lost in a storm or on an uncharted shallow.

      That's true, we have become lazy assed bastards that sit on our butt all day, but you also have to remember that the explorers of old didn't have to worry about finding air to breath and if they where hungry, they just cast out a fishing line.

      But still, we have to take chances, even if, after a failed mission, NASA gets attacked everywhere, even here. And we here should know that working on anything advanced, whether it's an operating system or a spaceship automatically leads you to failures. It's what comes out in the end that counts.
      So would you please stop attaching NASA the next time they lose a probe. Every larg projects come up with difficulty sometime or other, but problems are solved, even if it has to be iwth a second probe.

    • Course, in those days, not only were the risks of travel balanced by the rewards of escaping the local law's short arm or coming back with (possibly someone else's) valuable cargo, but your alternative was to stay home, eat boot leather in bad years, and probably die of typhus or cholera.

      Our best and brightest aren't going to take up the torch of discovery if it's too much harder than the advanced life of relative ease and comfort they can have right here on Earth.

  • So all those dreams recently, where my teeth fall out.. are on Mars! I knew something was strange.. wait, am I dreaming that? or is this part of my Rekall vacation?

  • Artificial Gravity? (Score:4, Interesting)

    by John_Booty ( 149925 ) <johnbooty@booty p r o j e c t . o rg> on Tuesday August 28, 2001 @01:22AM (#2224325) Homepage
    What if they just created artificial gravity via centripetal force by simply rotating the craft about its axis on the way to Mars? I don't know the physics involved here, maybe it's just not possible to create enough gravity that way unless you have a spacecraft with a really big radius, such as the space station in 2001.

    I'm sure that more-informed minds then mine have already considered this simple idea, I'm just wondering why it's not feasible.

    If the manned Mars spacecraft wasn't big enough to create sufficient gravity that way, maybe they could just hire really fat astronauts, in order to make the most of the limited gravity. just kidding...

    • Re:Artificial Gravity? (Score:4, Interesting)

      by Goonie ( 8651 ) <robert.merkel@b[ ... g ['ena' in gap]> on Tuesday August 28, 2001 @01:33AM (#2224352) Homepage
      It's quite possible. The trouble is that the smaller the "orbit", the faster you have to spin to get decent gravity, and you start getting rather disorienting side effects. However, what you do is get a big heavy piece of stuff (for instance, a spent upper stage of a rocket), a nice big strong (but actually not all that heavy) rope, and attach your Mars vehicle to that, and set the system spinning. If you make your rope reasonably long, the rotation can be nice and slow, and when you get to Mars you just cut the rope and let the useless spent upper stage go.

      In Robert Zubrin's book The Case For Mars he proposes just such a system. I haven't checked the physics myself, but it's introductory college physics to do (in fact, I should probably grab my old physics book and do the math just to see if I still can :) )

    • Artificial gravity would seem to be the way to go. How do you do it? There have been a lot of proposals, of course, and everyone has seen movies like 2001 with big rotating spacecraft and huge spoke-wheeled space stations. One of the most interesting proposals I've seen would use a spacecraft that starts as a single small module for launch, but then seperates into two pieces. Linked together by a long tether, the two halves of the craft rotate about each other during transit in order to create centripetal gravity. I believe that the tether is also used as a power cable, and the power source is in one module with the crew and provisions in the other. In this way, you get a small, light ship with the artificaial gravity benefits that come from have a very long rotational axis. If you're using a nuclear power source, you also get distance-based shielding. --I like flat panel monitors, but fish tastes good.
    • It is possible to use last, burnt out stage of the rocket as a counterweight. You tether the stage and the landing module together and give the components a spin.

      Calculations suggest that this is indeed possible. I think the idea is explained in more detail in
      "The Case for Mars" [amazon.com], a highly recommended, factional book.
    • What if they just created artificial gravity via centripetal force by simply rotating the craft about its axis on the way to Mars?

      That's exactly what HAL's ship from 2001: A Space Odyssey did on the way to Jupiter. I remember going to the playground as a kid and sitting on a merry-go-round while others pushed. Once it's going fast enough, you'll feel plenty of force. And without friction, it will just keep spinning. Actually, I wonder how much influnce people moving around in there would have. It ought to be easy to compensate for.

      Here's another idea for getting gravity on the voyage:

      If they could get a large mass to follow them the whole way, then they'd have plenty of gravity. Of course, its size would need to be on the order of the Earth's, but I'll leave the details of implementation to someone else.

    • From my experience, this topic seems to be considered mostly by sci-fi writers. Many people have seen 2001 with the rotating stations. A more recent example is Babylon 5 - the entire station (which is something like 2 miles long and a fraction of that in diameter) rotates. It creates some nice visual effects, but rotation-generated "gravity" has its problems.

      The "gravity" is much higher towards the outer parts of a rotating ship and non-existant in the core. In Babylon 5, this is actually where some cross-station transportation took place. They even had the lead character experience the weightlessness of being in the center, with the danger of gradually moving to smack into the quickly rotating station. But that's another story.

    • The Mars Society has already thought of this. You are correct when you assume that you need a ridiculously large vessel to make this feasible. But, the way the Mars Society theorists got around the issue is to separate the craft into two parts separated by a teflon tether, of a sort. The first part of the craft would be larger and contain everything the astronauts would need on the voyage to Mars. The second part would be considerably smaller but nearly equivalent in weight (space for living astronauts is considerable). The two parts would then be spun around each other with initial and occasional blasts from small, dedicated retro rockets.

      The problem is, in order to simulate 1G of gravity (equal to that on Earth), you need a certain mixture of size and speed. For safety reasons, the tether can only be so long. So you would think they could just increase the speed. It works on paper, but when put into practice with such a small vessel, spinning at that speed would most likely just induce vertigo in the astronauts and the small size of the craft would allow small variations in the rotation to create noticeable rocking, much like a ship at sea. Luckily, there is an easy solution to this problem. Just simulate the gravity on Mars. Spinning at a reasonable speed, the craft would be able to simulate the necessary 0.38G safely and easily. And then there's less of a problem on both landings (Mars and Earth), because even if you were able to simulate full Earth gravity, would you really want to? When you land on Mars, some considerable amount of time would have to be devoted to getting acclimated to the gravity, during which time the astronauts would not be fully operational and not exactly able to do the required exploration work. With a gravity of 0.38G on the transporting spacecraft, that acclimation can be done over the 6 month travel period and the astronauts can hop out and get their work done immediately after landing.

    • Or just a roataing section.
      Not too difficult, and very plausable. The problem is that it doesn't fit with NASA's current spend very very little methodilogy. anything that we sent do mars with people in it had better be the most expensive and over-engineered mechanical marvel the human race has ever created. The problem is that we're trying to get there in a volkswagon bug instead of a Lincoln navigator. and we really need to be bringing the Lincoln.
  • As I recall, most astronauts who are in space for any extended period of time have a fairly rigorous workout routine to prevent muscle atrophy. Obviously, exercising with spring based machines (as it is fairly pointless to try to "lift" weights) helps to keep muscles in shape but also stresses the bones also helps maintain bone mass.

    The Discovery article states "...in both older women and weightless astronauts, the bone-repair mechanisms in the body shut down." Are there any doctors out there that can explain (in detail) what happens to the body in low gravity that causes bones to atrophy?

  • Why can't the crew habitat section rotate around the common axis of the vessel (two modules actually, in order to neutralize the torque generated, spinning opposite of each other). You know, like all of those wheel-shaped space stations you read about in science fiction, just on on a ship instead. Then they could have Earth-normal gravity the whole trip.
  • Hope they figure out that tooth problem. Would hate to have our astronauts miss that golden fresh Martian sweet corn.

    BTW: Did anybody else get a hoot out of those videos from Devan (spelling?) Island. I think it's wild that grown up, presumably intelligent, people are trying to simulate extended stays on the Martian surface.

    Not only do they learn a lot, but they get to wear those neato space suits.
  • Does the tooth faerie require a space suit?
  • Even better would be to avoid the problem altogether by building a spacecraft that spins, generating artificial gravity, said Marsh Cuttino...

    Uhhh, just how much spin would be needed to generate enough simulated gravity to cancel the onset of osteoporosis, and can you imagine the havoc that would play on the spacecraft's structure over time? Hell of an engineering problem to wrestle with...

    On the other hand can you imagine a year of zero G sex?
  • Here is the Mars Fact Sheet [nasa.gov] from NASA [nasa.gov]. The surface gravity on Mars is 0.377 times that of Earth, which I would expect to cause at least some bone loss, but of course IANAD.

    Incidently the year in space, 6 months each way, seems somewhat short to me. I thought they generally planned for closer to a 9 month journey when sending things over there. Of course the really important point is whether we can make more fuel once we get there. Carrying all the fuel for a return trip with you would make for a lot heavier and slower trip.

    In any case men won't be going there soon. We haven't even been to the moon in ages, and we might as well test whatever technology we plan on using on some long duration lunar missions.
    • As Robert Zubrin describes in his book "The Case for Mars" [amazon.com], rocket fuel can be generated with a simple, proven reaction from the martian atmosphere.

      And no - the book is NOT a fictional work. Robert Zubrin is the guy convinced the NASA to change the plans for manned mars mission to the "long trip model".
  • What are teeth good for anyway? I'm sure they can just get nasa to hook them up with all liquid food, I hear it's pretty tasty. ;)
  • So much for the standard picture of the intrepid space explorer! I doubt Doc Smith would have sold so many books if his main character in the Lensman series was named Kimball "Gums" Kinnison.
  • Cost aside (ha!), if they were to build something like the Leonov in "2001", making the arms longer would increase the apparent gravity at the ends. Balance the relationship between arm length and angular velocity to get 1g at the ends. Do that many of the degeneration/atrophy issues ought to disappear.

    On Earth, it's 1 g, on Earth's moon it's about 1/6 g, on Mars it's about 1/3 g.

    Maybe I ought to take a crack an idea I had a few years ago for a cheap launch vehicle- sort of a motorized bolas...
  • Tooth loss is one thing I never really thought about for a manned mission to Mars, but it is just one thing. What are the other problems we have to solve to send humans to another planet? Besides the obvious DVD region jokes, and money from Washington DC?

    • You have to send enough people so that they all don't go crazy. We will have to a system like HAL in the long run?
    • Creating Artificial Gravity, most likely only way to go...
    • Are there any ideas to shorten trip time?
    • Are we going to send a unmanned mission to set up a nice cushy environment for the astronauts to stay at once we're there? A small bio-dome? How will that work?
    • What exactly are we going for anyways? Search for water, search for life like bacteria? Origins of the universe or solar system?
    • How long will it take for permanent Moon/Mars colonies, 100+ years? Why will we need those?
    Is there any better comprehensive list out there listing all the dangers with possible solutions on space travel out there?
  • I'll just say kudos to Hemos for the attention-grabbing headline. Made me giggle even before I read the story. :)
  • Bone weakening? Lost teeth? Sounds like the normal effect of a 'geek' diet to me. Bring it on!

    -s

  • teef? (Score:1)

    by FFON ( 266696 )
    i already got no teef... can i be a astronot?
  • If they switch the minty-fresh taste of colgate, their teeth will stay strong, white, and clean.
  • "The bone-weakening effects of zero-gravity environments might lead to permanent tooth loss, says a government dentist. "

    Can it be non permanent ??!!

  • 30 Hertz vibrations (Score:5, Informative)

    by Ratface ( 21117 ) on Tuesday August 28, 2001 @02:37AM (#2224449) Homepage Journal
    Just this morning I was reading issue 2303 of New Scientist and read an article that states that research has shown that the activity of standing on a vibrating platform moving at 30 hertz for 20 minutes a day has induced sheep to gain 35 % more bone mass within a year.

    Trials have been started on elderly female patients with osteporosis and seem to be showing positive results.

    Of course, 0G could make it difficult to stand *on* a vibrating platform, but these experiments must be able to teach reserachers something about ways to combat the problems. If tiny, high frequency strains can help improve bone growth then there must be other ways to induce those strains within a 0G environment.

    • I used to know a physiotherapy postgrad student who was researching the use of ultrasound to achieve a similar effect. Ultrasound is more like 3500Hz, of course. Still, you can use it in zero gravity.

  • If I remember my biology classes correctly, teeth already are regarded as an evolutionary relic by some biologists, so they are bound to disappear anyway some time 'soon' (on the evolutionary timescale, that is).

    What's more: *of course* humanity will adopt to living in space, they will look different from the people living on earth, that's the whole point in evolution, isn't it?
    That this might bear some problems for the first spacefarers has already been a topic in SF literature, e.g. in C.M. Kornbluth's story "The Altar at Midnight".

    tom
  • And while we keep waiting to see some toothless astronauts, the brainless bureaucrates keep us tight to earth...

  • "Tommyknockers, Tommyknockers, knockin' at my door..."

  • Who needs teeth when astronaught food is generally pasty anyway?


    I know some tooth-impaired good ol' boys who would be excellent candidates for the Mars program. Far from pretty boys, they would not mind at all losing their remaining teeth.


    NASA should also contact Shane McGowan [formerly of The Pogues] if anyone can find him.

    In thpace ... no one can hear you thcream. [ridiculopathy.com]

  • I know that we all think that a spinning spacecraft is a wonderful idea, but it's a bit much.

    What about just a single chamber, perhaps along the lines of living quarters, that spun, much like the old amusement park rides?

    A certain amount of exposure to ~1g per day should be enough to ward off the deterioration of bone mass, and it would be cheaper than engineering an entire spaceship to spin fast enough to induce gravity.

    Of course, I'm certainly missing the key detail of this spinning chamber most likely staying in place while the rest of the ship spins, but I leave the tough work to the NASA engineers :-P
  • I would give my eye teeth for a trip to Mars, and so would any NASA astronaut.

    Clear the technological hurdles -- if the bone loss problem isn't solved by then, well, screw it. Take volunteers.
  • This dragon keeps coming up as one of the major reasons not to explore the solar system, and it's one of the easiest to put to bed. All you have to do is attach the spacecraft to its spent upper stage with a long tether, and spin the whole system like a baton. You can get modest gravities with reasonable (on the order of a hundred or so feet, depending on the mass of the upper stage and the spaceship) tether lengths and angular velocities. The nice thing is that even if the tether were to break, the only thing you'd be losing would be a useless hunk o' metal. The astronauts would of course be less comfortable, but the mission could be accomplished.

    If you're interested in this sort of thing, Robert Zubrin's "The Case for Mars" (http://www.marssociety.org has a copy for you) details things like navigation and maneuvering on a rotating platform.

  • It's certainly good to identify such problems and prepare for the ahead of time, but I'm not that worried about this. Science/Medicine are making good progress on preventing problems once they know about them (while IMO progress isn't as hot in the whole fixing-existing-problems domain). This feels like a readily-understandable problem.

    By the time we're ready (socially, financially and technologically) to make trips to Mars with such frequency that this is a serious problem, I feel confident that a supplemental drug and/or exercise regimen and/or artificial environment will be available to prevent this problem.

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