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Japan Moon Space

Japan Wants To Bring Artificial Gravity To the Moon (gizmodo.com) 104

"Researchers and engineers from Kyoto University and the Kajima Corporation have released their joint proposal for a three-pronged approach to sustainable human life on the Moon and beyond," reports Gizmodo. The first element involves "The Glass," which aims to bring simulated gravity to the Moon and Mars through centrifugal force. From the report: Gravity on the Moon and Mars is about 16.5% and 37.9% of that on Earth, respectively. Lunar Glass and Mars Glass could bridge that gap; they are massive, spinning cones that will use centrifugal force to simulate the effects of Earth's gravity. These spinning cones will have an approximate radius of 328 feet (100 meters) and height of 1,312 feet (400 meters), and will complete one rotation every 20 seconds, creating a 1g experience for those inside (1g being the gravity on Earth). The researchers are targeting the back half of the 21st century for the construction of Lunar Glass, which seems unreasonably optimistic given the apparent technological expertise required to pull this off.

The second element of the plan is the "core biome complex" for "relocating a reduced ecosystem to space," according to a Google-translated version of the press release. The core biome complex would exist within the Moon Glass/Mars Glass structure and it's where the human explorers would live, according to the proposal. The final element of the proposal is the "Hexagon Space Track," or Hexatrack, a high-speed transportation infrastructure that could connect Earth, Mars, and the Moon. Hexatrack will require at least three different stations, one on Mars's moon Phobos, one in Earth orbit, and one around the Moon.

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Japan Wants To Bring Artificial Gravity To the Moon

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  • Seems a bit far fetched to me
    • by zlives ( 2009072 )

      looks perfectly feasible FF-XX, i'd play that game.
      any ways why make it a cone, and not multiple cylinders rotating at same speed
      why have it sticking up out of the surface and not inside

      • by HiThere ( 15173 )

        Digging a hole is expensive. The large diameter helps reduce sensitivity to Coriolis.

        That still doesn't mean this is the right approach, of course.

        • by zlives ( 2009072 )

          i was thinking sub surface cylinder of uniform radius (miles wide)instead of cone, multiple cylinders stacked... in a magical redundant way so it never fails... until sepiroth makes his move and the end is neigh for our brave heroes to save the moon.

    • The Moon is pretty far for a construction project, but just think of this a train on a steeply banked track. For a large lunar station make it a train 628 m long on a 100 m radius track going 30 m/s with magnetic levitation, The lunar surface supports the track. This spec creates 0.9 G but lunar gravity adds to it.

      You would probably build this by digging a trench for the track, and have a bridge across the train-station for entry and exit at the hub.

      Smaller stations are easier to do, but the principle remai

      • This paper [archive.org] indicates that 2 RPM causes no problem from differential angular acceleration effects, but that people can adapt to 6-10 RPM. The train-station I describe above is 3 RPM. For much smaller stations, still built on the same model (magnetically levitated, supported by the lunar regolith) a compromise with lower G and higher RPM allows minimizing structure size. A 7 m radius station at the upper limit of 10 RPM would give 0.78 G, but it would be better not to push human adaptation that high I expect

      • Or instead of a track, just suspend it off a central pole like those spinning "swing" rides at the amusement park.

        It'd need to be a heck of a solid pole, but that's potentially less of a challenge than building a huge ring track across lunar regolith. Which seems to be mostly sand and dust, with none of the organic material that binds it together into more solid dirt here on Earth.

      • by q_e_t ( 5104099 )
        Trains? Can't you use a car analogy?
    • Not an engineer, but ⦠Lot of water in that structure. If it gets unbalanced at all, water will flow downhill unbalancing it further, water flows faster â¦
  • Why would you want it on the moon or anywhere?

    • Re:Gravity sucks (Score:4, Informative)

      by JanSand ( 5746424 ) on Tuesday July 12, 2022 @02:33AM (#62695562) Homepage
      As gravity is one of the fundamentals of almost almost everything alive that developed on this planet, life without it on any space satellite habitation creates difficulties in metabolism. Perhaps the limited gravity on the Moon or Mars is tolerable but astronauts who spend time on the space station suffer physiological difficulties in the process. Perhaps special individuals must be biologically developed for long term life on any place off this planet.
      • by quenda ( 644621 )

        As gravity is one of the fundamentals of almost almost everything alive that developed on this planet,

        "everything"?! Far from it, most life has been in the oceans, where a doubling or halving of gravity would make little difference. It's only us newcomer land-creatures who are sensitive to its strength. Especially the larger of us.

        • Re:Gravity sucks (Score:5, Interesting)

          by war4peace ( 1628283 ) on Tuesday July 12, 2022 @03:29AM (#62695632)

          "everything"?! Far from it, most life has been in the oceans, where a doubling or halving of gravity would make little difference.

          Are you sure? One of the ways fish estimate depth is through pressure difference, which is directly linked to gravity value.

          • by tragedy ( 27079 )

            Are you sure? One of the ways fish estimate depth is through pressure difference, which is directly linked to gravity value.

            Good point, although I imagine that's something that they could probably adapt to.

          • by quenda ( 644621 )

            "everything"?! Far from it, most life has been in the oceans, where a doubling or halving of gravity would make little difference.

            Are you sure? One of the ways fish estimate depth is through pressure difference, which is directly linked to gravity value.

            Analogously, the human sense of balance soon adapts to microgravity. But land-dwellers have bigger problems.
            We are talking about lower or higher gravity, not zero-G. Yes, there are processes affected by, and depending on, gravity in ocean life. But they would adapt far more easily to the *degree* of gravity.
            It is a lot easier to calibrate sensors than to redesign a circulatory system.

        • As gravity is one of the fundamentals of almost almost everything alive that developed on this planet,

          "everything"?! Far from it, most life has been in the oceans, where a doubling or halving of gravity would make little difference. It's only us newcomer land-creatures who are sensitive to its strength. Especially the larger of us.

          Thank you, Captain Pedantic, for rescuing us from the correct answer to the question about why we’d want gravity in space. Imagine the horror had you not been here to save us from a correct answer that has a phrasing with which we can quibble!

          • Thank you, Captain Pedantic

            It is not pedantry. "Life" doesn't need 1g-gravity. People do.

            We only need artificial gravity on the moon if we have people there.

            Which makes more sense?

            1. Spend billions over and over the make each project human-compatible.

            2. Spend billions once to develop robots that make humans redundant.

            Get rid of the people, and most of your problems are solved.

          • Delighted to receive gratitude,
        • by JanSand ( 5746424 ) on Tuesday July 12, 2022 @03:44AM (#62695670) Homepage
          The next time octopuses launch their satellite habitations to be operated by eight tentacled astronauts I will take that into account.
        • The concept that ocean dwellers are not responsive to gravity requires examination so it might be a good idea to support in the matter by selecting an especially bright dolphin who shows linguistic talent to teach it a human language for at least elementary accommodation to social interaction with scientists and training it in the basics of becoming an astronaut and qualifying it for a stay in the space station for a few months. They are quite bright animals and if the experiment is a success it can become
          • by dargaud ( 518470 )
            You should read the Uplift trilogy [wikipedia.org] by David Brin, where the central idea is spacefaring species 'uplifting' other convenient species to make them more intelligent and useful. Humans do it to dolphins because they make better space pilots... Very good and insightful series of books.
          • And cats, as well. I'd really like to see how they adapt to zero g, and if they learn to live floating in the middle of the compartment or prefer to hang on to to bulkheads using their claws. Dogs are also very adaptable, but they're not as good at climbing, and their claws aren't designed for grasping. I'll leave the question of litter boxes as an exercise for the reader.
            • Unfortunately, although elephants have demonstrated signs of real intellect, it seems unlikely they will ever qualify as astronauts.
        • Check again. filtering, and settling, are still affected by the relative density of materials. So is floating, and it's likely involved in the successful gestation of eggs, whether externally or in the womb.

        • by Rhipf ( 525263 )

          You do realize that even in the oceans there is gravity.
          Sure the force of gravity towards the center of the earth can be offset by buoyancy in the lifeforms but that life form wouldn't have created that bouncy without gravity to fight against. Take any sea creature and transport them to the Moon or Mars and I highly doubt that they will be any better able to handle the low gravity than land creatures would.
          There may be creatures that can handle the different pressures in the ocean but they still evolved to

      • by eth1 ( 94901 )

        Perhaps special individuals must be biologically developed for long term life on any place off this planet.

        I think this is more or less the right path.

        If we're serious about becoming a multi-planet space-faring civilization, we'll need to make intelligent choices about when it make sense to adapt the environment to us, and us to the environment.

        Interplanetary space travel (let alone interstellar) is going to be so cumbersome and expensive for the foreseeable future that I really only see people on those trips as one-way colonists (most exploration will be done by robots). Thus, it makes more sense to facilitate

        • How long until the wars begin? Just developing in low gravity environments will make people tall and attenuated. Human nature being what it is how long until there are slurs for this? The Expanse covers this well.
        • Although specially developed variations of humans may be the possible way for extraterrestrial colonization, this may also destroy their ability to live on this planet so persecution of these individuals may never arise.
  • At that rate of rotation, I would think it's going to start messing with the inner ear and cause all sorts of vertigo problems. Not to mention how the high rate of spin will affect trajectories inside the structure, so nothing's going to work as humans expect it, least of all their balance...

    • by quenda ( 644621 )

      Not to mention how the high rate of spin will affect trajectories inside the structure, so nothing's going to work as humans expect it, least of all their balance...

      The seasoned crew will have a lot of fun playing tennis with the new arrivals.

    • At that rate of rotation, I would think it's going to...cause all sorts of vertigo problems.

      Imagen smocking bongz in dat cone:

      HEY MAN IM TOTES SPINNING OUT, NO SRSLY@@@

    • by tragedy ( 27079 )

      At that rate of rotation, I would think it's going to start messing with the inner ear and cause all sorts of vertigo problems. Not to mention how the high rate of spin will affect trajectories inside the structure, so nothing's going to work as humans expect it, least of all their balance...

      3 RPMs is actually just about the limit where pretty much everyone is able to handle it except the hypersensitive. You would need to adjust for which way you're facing when playing a game of darts, but you almost certainly would not get nauseous or confused after a few days at least. It would be easier than an oceangoing boat in mild weather.

    • This was one of the best things about the sci fi show the expanse. Onboard a ship using a centrifuge to generate artificial gravity, a character pours liquid into a cup but has to do it way off center as gradient is so high. It’s the little details like that.
      • And you will weigh more walking in one direction than the other.
        • And you will weigh more walking in one direction than the other.

          Yes. The biggest issue is your height, your environment, is a large percentage of the rotational radius - you can easily see the curvature essenally. This is the gradient of force per unit distance. So on a 200 foot diameter ship, with a cylindrical spinning chamber, if you were 5 feet tall you’re 5% of the radius and the curvature of the hull looks quite curved. Instead have two pods add to the same mass but separated 40 miles on a thin steel bar, spinning about their center of mass 20 miles awa

      • Ooooh, link please, I can't remember that! It's been a while since I saw that series, but I loved how accurate space flight was, all the way from "Amos, hit your boots and hold on, we're doing high-G maneuvers!!" to "Ship, plot a course from here to Ganymede, thrusters only, no engines!".

  • Won't people living in lower gravity on the moon just allow for even more obesity?

    • Astronauts have to be pretty damn fit before they're sent up on a proper launch (ie not a Bezos pretend rocket), more so if they're going to go to the moon which means they're already used to eating well and doing exercise.

      Also food will be limited on a moonbase anyway so no one is going to be tucking into donuts and burgers every day.

      What WILL be a problem is muscle wastage. Not as bad as in zero G but will still probably be significant which is what this is probably designed to counteract though as someon

    • by AmiMoJo ( 196126 )

      Health problems stemming from long times spent in zero or low gravity are a real concern. People lose bone mass, lose muscle, suffer from vision problems and more.

      That said, centrifugal "gravity" has been tried and doesn't work very well. One of the main problems is that the force isn't straight down, it's at an angle. The angle depends on the radius of the circle. The result is that when you reach out to pick something up, a lifetime of muscle memory goes out the window because gravity isn't working how yo

      • That said, centrifugal "gravity" has been tried and doesn't work very well. One of the main problems is that the force isn't straight down, it's at an angle. The angle depends on the radius of the circle. The result is that when you reach out to pick something up, a lifetime of muscle memory goes out the window because gravity isn't working how you expect, and unless the ring is truly massive it will actually vary along the length of your arm.

        Rubbish. It's straight down, the math is easy.

        Experiments have been done on Earth and they were never very successful, except at determining that it doesn't work well.

        Oh, they tried it on earth, where there's already a gravitational field? Yeah, that won't work. 1G outwards + 1G downwards = 45 degrees.

        • the force isn't straight down, it's at an angle. ...

          Rubbish. It's straight down, the math is easy.

          On earth, if you lift your arm away from your torso, your forearm experiences some force of its own accord -- 1G worth of gravity pulls it straight down.

          Standing in a big centrifuge in a weightless environment, all forces on your extended forearm are transmitted through your torso instead.

          • by tragedy ( 27079 )

            On earth, if you lift your arm away from your torso, your forearm experiences some force of its own accord -- 1G worth of gravity pulls it straight down.

            Standing in a big centrifuge in a weightless environment, all forces on your extended forearm are transmitted through your torso instead.

            I'm confused. You might need to restate this. On Earth, with normal gravity, how are forces on your extended forearm _not_ transmitted through your torso?

            • by _merlin ( 160982 )

              On Earth, with normal gravity, how are forces on your extended forearm _not_ transmitted through your torso?

              On earth, gravity is pulling your arm directly towards the earth's centre of mass, independently of its attachment to your body. In a centrifuge, the centripetal acceleration used to simulate gravity is only being transmitted to your arm through its attachment to your body. It's quite disconcerting.

              • by ceoyoyo ( 59147 )

                In a centrifuge, the centripetal acceleration used to simulate gravity is only being transmitted to your arm through its attachment to your body.

                The centripetal force is the analog to the force resisting gravity in the non-rotating frame. Both forces are transmitted entirely through your shoulder to your arm.

                The centrifugal force is the gravity analog. It is straight "down" in both cases and has nothing to do with your shoulder.

              • by tragedy ( 27079 )

                On earth, gravity is pulling your arm directly towards the earth's centre of mass, independently of its attachment to your body. In a centrifuge, the centripetal acceleration used to simulate gravity is only being transmitted to your arm through its attachment to your body. It's quite disconcerting.

                I sort of see what you're getting at here. If you're in freefall, and you spin up something like this from a stop and you have an object not touching the floor, and you're in a vacuum, that object will just just hang there. So, for example, if you were to detach your arm before it starts spinning and your feet are on the floor then, when it starts spinning, you would start to experience a "downward" force, but your arm would stay stationary (although from your point of view it would be moving in a loop-de-l

        • Re:Lower gravity? (Score:4, Informative)

          by AmiMoJo ( 196126 ) on Tuesday July 12, 2022 @04:10AM (#62695712) Homepage Journal

          Scott Manley did a great video about it: https://youtu.be/nxeMoaxUpWk [youtu.be]

          At about 10 minutes in there is some footage of one of the experiments done on Earth. You can see that even simple tasks become difficult, and darts appear to travel along a curve when thrown.

          • The radius of that centrifuge was only a few meters and it was rotating about once every three seconds. That's short enough that their feet would be traveling noticeably faster than their heads. That's probably what's going on.

            The larger the radius, the less head:foot difference there will be. The device being proposed here has a radius of 100m and rotates once every 20 seconds. It will be a lot better.

        • Rubbish. It's straight down, the math is easy.

          The original poster is considering the forces created due to change in angular momentum as a body moves, as well as the centrifugal force. I have done the experiment myself in an earth-based centrifuge and the sideways pull on your arm as you raise it is quite disconcerting. You can try it for yourself on the right fairground ride.

          I don’t know how bad the effect would be on a centrifuge of the scale of the one described in the article. I think the effect would be less as the change would be smaller

          • by HiThere ( 15173 )

            You probably wouldn't want to play darts, tennis, or other such games. But with a larger radius the effects diminish quite a lot.

          • Yep. The centrifuge in that video is spinning at about 20rpm. That will throw things off.

      • The prospects seem even less promising for on-planet implementations: the engineering gets a lot nastier, since even moon-level gravity is a lot of gravity when you are trying to build a centrifuge on a heroic scale; and (unless there's basically no reason for humans to be on the planet at all) the inhabitants will only get to enjoy the psuedo gravity part of the time and will have to adjust to moving between it and the actual gravity every time they want to go outside to do whatever it is we sent humans to
        • by HiThere ( 15173 )

          Part of your argument depends on the external work not being done by telefactors (the press calls those "robots", but they've got really minimal smarts). I think, though, that most of it would be. The people would be needed on site to avoid light-speed delay in controlling things. But just how many will depend greatly on how the tech evolves.

          OTOH, a lot depends on what the "minimum long-term gravity need" is for people, and I don't think we know that. We know that zero-g doesn't work well.

      • by tragedy ( 27079 )

        Experiments have been done on Earth and they were never very successful, except at determining that it doesn't work well.

        Which experiments are these? Were they at the local carnival? It certainly hasn't been tried in space.

        • by AmiMoJo ( 196126 )

          Both NASA and the USSR/Russia did experiments. The Earth's gravity was not the problem, the the rotation was.

          • by tragedy ( 27079 )

            The rotation is definitely a problem with Nausea, etc. Not when the rotation is down around 3 RPMs or less though. Nearly anyone except the extremely hypersensitive can adjust at that rotation rate. It's not that different from adjusting to being on a boat. It takes a pretty big ring though. Obviously the giant ice-cream cone design is way out there. Among other problems, there's absolutely no rational reason that it would need to be a big cone, balanced on the tip. The floors do need to be sloped, but ther

      • by RobinH ( 124750 )
        This design appears to deal with the "at an angle" thing by taking moon gravity into account. At all points on the "glass" the net force of moon gravity vector plus centripetal vector is "down," i.e. perpendicular to the surface of the glass. You experience 1G at the top, and it goes all the way down to moon gravity at the bottom.
      • The radius of spin can be increased without building a giant wheel. Two habitat modules spinning on the ends of a mile-long cable would do nicely. Iâ(TM)d love to crack a beer and listen to a bunch of engineers discuss how to balance such a thing.
      • The force is always straight down, by definition. That is literally how we define "down". It's the direction the force of gravity points in.

        You know how people often refer to zero gravity in space as "free fall"? There is no difference at all between falling without anything to stop you, and simply not having any gravity. You only become aware that gravity is present and that you're falling when some other force gets involved. Like when you're standing on the ground, and it pushes your feet up and keep

  • Just saying...

    • The true bane to Proper Science Reporting.

      There is a lot of good science going on, however these scientist will need to take a break from their work, to publish some papers some may be actually tangential to their actual work, just to make sure their names are out there, as well the universities and grant holders get some credit.

      The study of Science tends to not fair well with the worlds economic systems. There is a lot of work, effort and money that often goes into No results. Or the findings actually beco

  • by 93 Escort Wagon ( 326346 ) on Tuesday July 12, 2022 @03:36AM (#62695654)

    I think an easier goal would be to bring artificial gravitas to the Moon.

    Okay, I'll show myself out now.

  • Rather than rotate the structure, rotate the people.

    Of course, to save costs, you could start with the Semi-circular Wall of Death :-) (apologies to whoever coined that joke first.)

    This surely isn't that difficult - fairgrounds have also had Waltzers and other high-g rides for decades.

  • by TuringTest ( 533084 ) on Tuesday July 12, 2022 @04:00AM (#62695698) Journal

    Nothing to worry about for those who are standing on a vertical wall at 400m height. Nope, nothing at all.

  • engineering (Score:4, Insightful)

    by Tom ( 822 ) on Tuesday July 12, 2022 @05:01AM (#62695762) Homepage Journal

    Because nothing could possibly go wrong. Except when you need to shut down the thing for maintenance every few years. Or if there's a power failure. Or someone presses the wrong button and all that water decides it doesn't want to say on what's now a wall...

    It might be easier to breed/bio-engineer humans that don't suffer from low gravity issues.

  • Okay the video is cool (the second one where you are on the moon, not the one with a blue sky.. nor the third one where you get turned upside to enter your bullet train capsule into a revolver speed loader..) It really makes you have an epiphany and try to imagine an amazing new world.

    BUT, I am thinking I would prefer it to be underground. If I am living in it I want a lot more shielding, easier maintenance, less stress, less disastrous failure modes. One meteorite hitting that thing is going to let all the

  • 100m diameter is far too small, and at rotational speeds that generate any meaningful amounts of gravity-like force, will lead to inner ear and balance issues, as well as nausea of subjects even turn their head.

    100m diameter is a big carnival ride, not a sustainable platform.

  • This sounds like another one of those GoFundMes.
  • The most fascinating question that arises here is What (in the moon or Mars) is a Hexatrack transport system? An electromagnetic railgun that shoots high speed passenger and cargo capsules? A launching facility that gives larger ships a rapid acceleration? Magic? Weird.
    • by ceoyoyo ( 59147 )

      Nearest I could figure is that it's a rotating spacecraft. That's only from a supposed picture of it though. All the articles seem to just mention it in passing.

  • Hard to see where the moon comes by. I mean you can try this more comfortably in orbit.

    Except if the idea is to mine the building materials from the moon, or build it in a covered zone to avoid radiation, you are better off with a free vehicle, I'd say.

  • The moon already has gravity...
  • Not anymore than 'self driving cars' are run by real 'artificial intelligence'.
  • Then use those to build some nice space colonies, then go from that.
    Skipping the part where a colony gets crashed into earth and kill half of the world population would be nice tho

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