14 ms·

Japanese researchers propose a concept for making artificial gravity on the moon

33 points by cheinyeanlim 4y ago

greedo 4y ago
Birds. They show birds flying in the cylinder...
- TeamMCS 4y ago
  They are carefully spun around using Carbon nanotubes
dreen 4y ago
Since were talking hundred-year timescales, wouldnt it be better to drill deep into the moon, set off a massive nuclear device inside the moons crust and build this thing in the resulting cavity? Then youre not only protected from muscle loss due to lack of gravity, but also from radiation (though probably not all). At least we would have a good use for all these nukes
- eterevsky 4y ago
  How would digging into the Moon help with gravity?
  - mkl 4y ago
    You could build the same spinning habitat in a hole in the ground, supported all around instead of balanced precariously on a stalk.
  - dreen 4y ago
    Its to help with radiation, and I guess meteorite strikes as well.
c048 4y ago
Why not simply build a space station instead with the same concepts? For argument's sake it would be a small O'Neil cylinder with a short shuttle or small space elevator to the moon. I'd expect research or mining sites to be quite basic and not like this habitat anyway. edit: I guess, if they build it in one of the moon's craters where the sun never shines, and where pockets of frozen water exist, it would make shielding from the sun a lot easier than a complex orbit.
- eterevsky 4y ago
  In space you don't even need a full cylinder, you can spin several habitats on a tether.
  - yellowapple 4y ago
    Technically you could do that on the Moon, too. Kinda like one of those carnival rides with the seats on chains and a tower spinning everyone around. In fact, maybe we should just cut to the chase and build amusement parks on the Moon. You know, for "physical and mental health" or something.
    - eterevsky 4y ago
      Oh, I know, it will be called Luna Park.
  - timbit42 4y ago
    Tethered, wheel and tubes are all the same thing. The minimal setup is one habitat tethered to an equal weight. As you add habitats, you eventually end up with a wheel. If you stack these wheels, you end up with a tube.
underlines 4y ago
I have concerns. - Everything falling down and the mess on the floor when this thing has a downtime - The still existing gravity towards the moon, which would be a constant additional force pulling you sideways (down) with 1/6 g
- SideburnsOfDoom 4y ago
  > still existing gravity towards the moon, which would be a constant additional force pulling you sideways That would be why it's a cone not a cylinder, to line up the "subjective down", the sum of forces including lunar 1/6 g; with the direction that the ground is in. Stopping would be an issue. But it looks like there is some accommodation for that in the form of a big "bathtub" at the bottom that could hold the water. IDK why there's so much water in the first place though.
- msk-lywenn 4y ago
  You mean everything fall left* and do a big mess on the wall, right? Frames of reference are fun. We also have a force pulling us sideways on Earth since it's rotating but without doing the math, it's probably a lot lower than 1/6 g, indeed. * or right, no idea if this is spinning clockwise or anti-clockwise.
  - Akronymus 4y ago
    And no matter which direction it spins, it depends on which direction you look. if you are looking "upwards" it falls "backwards", "downwards" = "forwards" and so on.
- yellowapple 4y ago
  The Moon's "atmosphere" is (practically) frictionless, so if you build this thing with a similarly-frictionless bearing (e.g. really strong magnets) it could theoretically spin near-indefinitely. Whether that's actually achievable (while still allowing people and supplies and water and oxygen and such to enter and exit) is of course another question.
- unsupp0rted 4y ago
deleted 4y ago
[deleted]
retube 4y ago
oh come on. this is the most transparent nonsense, doesn't make any sense. clearly a viral video marketing campaign.
mkl 4y ago
I can't read Japanese and just watched the videos, but what they illustrate seems pretty strange. Why is it mostly water instead of human living space? If the water's meant to let in more light, that's more likely to end up boiling the water during the day and freezing it solid overnight. https://en.wikipedia.org/wiki/Moon#Surface_conditions https://en.wikipedia.org/wiki/Moon#Surface_conditions
- yellowapple 4y ago
  Water happens to be a rather effective radiation shield, so I suspect that might be at least part of the reason why there's so much of it in the design.
throw93232 4y ago
Better way is to make a scientific committee, that would declare all side effects (muscle loss, bone density loss...) as totally random and uncorrelated to moon environment. Worked before...
necovek 4y ago
I always wonder why is nobody considering simply introducing "heavy" weights for every person to wear on planetary body like a moon? A sort of inverse-exoskeleton if you wish. For an average 75kg person, you'd need to add roughly 5x (375kg) to their weight to reach parity between Moon and Earth, which if done with iron or steel would need less than 50l of volume spread around the body. Heavier metals could be used for an even lower volume, of course (though you'd want to avoid poisonous metals like lead, mercury or osmium), though you might hit other bottlenecks (gold and platinum are 2.5x denser, and iridium even more so, but price comes into play — perhaps locally sourcing them on other "rocky" planets is more feasible). This does not resolve all of the issues mentioned in the article (like the effect on our internal organs, childbirth and such), but can definitely target a bunch of externally accessible muscles to keep them from getting atrophied. Perhaps this will be a cheap solution for those not living in the rotating megastructures. I should start collecting gold to be able to go sightseeing on the Moon.
- noSyncCloud 4y ago
  The additional mass will have tons of inertia, making ordinary activities like walking difficult, regardless of its current weight in the local gravity.
  - necovek 4y ago
    That's a great point. Perhaps it would have to be an actual mechanized exoskeleton that is passive only downwards. No cheapo solutions for us plebs then. /me dumps all the platinum in the trash.
- dghughes 4y ago
  > This does not resolve all of the issues mentioned in the article (like the effect on our internal organs, childbirth and such) Yeah it would be like anchoring a balloon. Sure it's not going to float away but it's still a balloon. It's our internal jiggly bits that are important too.
  - kleene_op 4y ago
throwaway290 4y ago
Does this address the Coriolis effect and other issues that make rotational "gravity" feel really weird compared to actual gravity (6:58 https://m.youtube.com/watch?v=nxeMoaxUpWk https://m.youtube.com/watch?v=nxeMoaxUpWk)?
smallerfish 4y ago
Somebody read and adapted Ringworld. Also unless I missed it, they fudged the part where the trains transition from the static tracks to the rotating structure. If so, that speaks volumes to their level of attention to detail. Did anybody pick up what the lit up pit in the middle was supposed to be?
idiocrat 4y ago
Again, there is a very practical reason why humans will never colonize the moon. And that reason is the moon dust. The moon dust is quite special as it is highly abrasive and sticks to anything because of the electrostatic charges. It seeps though any gap and will wear down and render any mechanical machine useless in very short time. Nothing soft (clothes, plastic) will survive on moon for more than few months. The dust is a nightmare for anything non-moon and there is no help.
- exitheone 4y ago
  There is help and it's not looking quite so grim. See one of the latest Real Engineering videos: https://www.youtube.com/watch?v=0k9wIsKKgqo https://www.youtube.com/watch?v=0k9wIsKKgqo Dust buildup can be significantly decreased by weaving conductors throughout the outer shells and applying a current to it.
- alanbernstein 4y ago
  What about... Being inside a building? You know, since humans need atmosphere anyway?
  - Akronymus 4y ago
    Any activity that requires going outside will inevitably get some amount of dust through the airlock. So, it is going to slow it down by a lot, but not stop it.
    - WJW 4y ago
      Well, vacuum cleaners are a thing and could probably be exported to the moon to take care of any dust getting inside. The dust is extra abrasive because it hasn't been exposed to weathering due to the lack of athmosphere and so has kept all the sharp edges. As soon as it gets inside and gets chafed/bumped around, many of the sharper edges will abrade. Of all the challenges for making humans live on the moon, sharp dust is one of the smaller ones.
      - 4y ago
ken47 4y ago
I find the title a little bit strange. Japan, the country, did not propose anything. Specific entities within Japan did. Perhaps I'm too post-nationalistic for this article's title.
- senttoschool 4y ago
  Same for any news out of China in the western media. It is as if people in the West thinks the entirety of China is united on every decision, invention that comes out of every entity in the country.
  - Fatnino 4y ago
    More like, "comes through the country".
  - meany 4y ago
    Doesn’t your remark make the same type of generalization about the West that you accuse the West of making about China.
deepdriver 4y ago
YouTuber Scott Manley has a great video on artificial gravity in space, including concepts that resemble the article's proposal: https://www.youtube.com/watch?v=nxeMoaxUpWk https://www.youtube.com/watch?v=nxeMoaxUpWk Before I watched the video, I didn't know the Soviet Union tested a (small) centrifuge for artificial gravity in space back in the 70s: https://en.wikipedia.org/wiki/Kosmos_782 https://en.wikipedia.org/wiki/Kosmos_782
yellowapple 4y ago
I feel like building this as a spinning ring (possibly inside a crater) makes more sense from a structural integrity standpoint (and possibly also a radiation shielding standpoint). Granted, lunar gravity probably makes structural integrity about ¹/₆ᵗʰ as hard to achieve as on Earth, but the spinning tower still seems a bit precarious.
ekianjo 4y ago
> Kyoto University partnered with construction company, Kajima Corp, So a university and a corp = Japan now. Wow. So next time Facebook partners with some academics, we can say "The US proposes..." ?
ekianjo 4y ago
Why does it have to be ON the moon though? An orbital station would rotate just the same, and if you are close enough to the moon you could still travel to the surface now and then for specific missions.
a5withtrrs 4y ago
Aren't there bigger issues...? Like no atmosphere protecting from radiation and things like space debris/projectiles?

33 points by cheinyeanlim 4y ago

greedo 4y ago

Birds. They show birds flying in the cylinder...

TeamMCS 4y ago
They are carefully spun around using Carbon nanotubes

dreen 4y ago

Since were talking hundred-year timescales, wouldnt it be better to drill deep into the moon, set off a massive nuclear device inside the moons crust and build this thing in the resulting cavity? Then youre not only protected from muscle loss due to lack of gravity, but also from radiation (though probably not all). At least we would have a good use for all these nukes

eterevsky 4y ago
How would digging into the Moon help with gravity?
- mkl 4y ago
  You could build the same spinning habitat in a hole in the ground, supported all around instead of balanced precariously on a stalk.
- dreen 4y ago
  Its to help with radiation, and I guess meteorite strikes as well.

c048 4y ago

Why not simply build a space station instead with the same concepts? For argument's sake it would be a small O'Neil cylinder with a short shuttle or small space elevator to the moon. I'd expect research or mining sites to be quite basic and not like this habitat anyway. edit: I guess, if they build it in one of the moon's craters where the sun never shines, and where pockets of frozen water exist, it would make shielding from the sun a lot easier than a complex orbit.

eterevsky 4y ago
In space you don't even need a full cylinder, you can spin several habitats on a tether.
- yellowapple 4y ago
  Technically you could do that on the Moon, too. Kinda like one of those carnival rides with the seats on chains and a tower spinning everyone around. In fact, maybe we should just cut to the chase and build amusement parks on the Moon. You know, for "physical and mental health" or something.
  - eterevsky 4y ago
    Oh, I know, it will be called Luna Park.
- timbit42 4y ago
  Tethered, wheel and tubes are all the same thing. The minimal setup is one habitat tethered to an equal weight. As you add habitats, you eventually end up with a wheel. If you stack these wheels, you end up with a tube.

underlines 4y ago

I have concerns. - Everything falling down and the mess on the floor when this thing has a downtime - The still existing gravity towards the moon, which would be a constant additional force pulling you sideways (down) with 1/6 g

SideburnsOfDoom 4y ago
> still existing gravity towards the moon, which would be a constant additional force pulling you sideways That would be why it's a cone not a cylinder, to line up the "subjective down", the sum of forces including lunar 1/6 g; with the direction that the ground is in. Stopping would be an issue. But it looks like there is some accommodation for that in the form of a big "bathtub" at the bottom that could hold the water. IDK why there's so much water in the first place though.
msk-lywenn 4y ago
You mean everything fall left* and do a big mess on the wall, right? Frames of reference are fun. We also have a force pulling us sideways on Earth since it's rotating but without doing the math, it's probably a lot lower than 1/6 g, indeed. * or right, no idea if this is spinning clockwise or anti-clockwise.
- Akronymus 4y ago
  And no matter which direction it spins, it depends on which direction you look. if you are looking "upwards" it falls "backwards", "downwards" = "forwards" and so on.
yellowapple 4y ago
The Moon's "atmosphere" is (practically) frictionless, so if you build this thing with a similarly-frictionless bearing (e.g. really strong magnets) it could theoretically spin near-indefinitely. Whether that's actually achievable (while still allowing people and supplies and water and oxygen and such to enter and exit) is of course another question.
unsupp0rted 4y ago

deleted 4y ago

[deleted]

retube 4y ago

oh come on. this is the most transparent nonsense, doesn't make any sense. clearly a viral video marketing campaign.

mkl 4y ago

I can't read Japanese and just watched the videos, but what they illustrate seems pretty strange. Why is it mostly water instead of human living space? If the water's meant to let in more light, that's more likely to end up boiling the water during the day and freezing it solid overnight. https://en.wikipedia.org/wiki/Moon#Surface_conditions https://en.wikipedia.org/wiki/Moon#Surface_conditions

yellowapple 4y ago
Water happens to be a rather effective radiation shield, so I suspect that might be at least part of the reason why there's so much of it in the design.

throw93232 4y ago

Better way is to make a scientific committee, that would declare all side effects (muscle loss, bone density loss...) as totally random and uncorrelated to moon environment. Worked before...

necovek 4y ago

I always wonder why is nobody considering simply introducing "heavy" weights for every person to wear on planetary body like a moon? A sort of inverse-exoskeleton if you wish. For an average 75kg person, you'd need to add roughly 5x (375kg) to their weight to reach parity between Moon and Earth, which if done with iron or steel would need less than 50l of volume spread around the body. Heavier metals could be used for an even lower volume, of course (though you'd want to avoid poisonous metals like lead, mercury or osmium), though you might hit other bottlenecks (gold and platinum are 2.5x denser, and iridium even more so, but price comes into play — perhaps locally sourcing them on other "rocky" planets is more feasible). This does not resolve all of the issues mentioned in the article (like the effect on our internal organs, childbirth and such), but can definitely target a bunch of externally accessible muscles to keep them from getting atrophied. Perhaps this will be a cheap solution for those not living in the rotating megastructures. I should start collecting gold to be able to go sightseeing on the Moon.

noSyncCloud 4y ago
The additional mass will have tons of inertia, making ordinary activities like walking difficult, regardless of its current weight in the local gravity.
- necovek 4y ago
  That's a great point. Perhaps it would have to be an actual mechanized exoskeleton that is passive only downwards. No cheapo solutions for us plebs then. /me dumps all the platinum in the trash.
dghughes 4y ago
> This does not resolve all of the issues mentioned in the article (like the effect on our internal organs, childbirth and such) Yeah it would be like anchoring a balloon. Sure it's not going to float away but it's still a balloon. It's our internal jiggly bits that are important too.
- kleene_op 4y ago

throwaway290 4y ago

Does this address the Coriolis effect and other issues that make rotational "gravity" feel really weird compared to actual gravity (6:58 https://m.youtube.com/watch?v=nxeMoaxUpWk https://m.youtube.com/watch?v=nxeMoaxUpWk)?

smallerfish 4y ago

Somebody read and adapted Ringworld. Also unless I missed it, they fudged the part where the trains transition from the static tracks to the rotating structure. If so, that speaks volumes to their level of attention to detail. Did anybody pick up what the lit up pit in the middle was supposed to be?

idiocrat 4y ago

Again, there is a very practical reason why humans will never colonize the moon. And that reason is the moon dust. The moon dust is quite special as it is highly abrasive and sticks to anything because of the electrostatic charges. It seeps though any gap and will wear down and render any mechanical machine useless in very short time. Nothing soft (clothes, plastic) will survive on moon for more than few months. The dust is a nightmare for anything non-moon and there is no help.

exitheone 4y ago
There is help and it's not looking quite so grim. See one of the latest Real Engineering videos: https://www.youtube.com/watch?v=0k9wIsKKgqo https://www.youtube.com/watch?v=0k9wIsKKgqo Dust buildup can be significantly decreased by weaving conductors throughout the outer shells and applying a current to it.
alanbernstein 4y ago
What about... Being inside a building? You know, since humans need atmosphere anyway?
- Akronymus 4y ago
  Any activity that requires going outside will inevitably get some amount of dust through the airlock. So, it is going to slow it down by a lot, but not stop it.
  - WJW 4y ago
    Well, vacuum cleaners are a thing and could probably be exported to the moon to take care of any dust getting inside. The dust is extra abrasive because it hasn't been exposed to weathering due to the lack of athmosphere and so has kept all the sharp edges. As soon as it gets inside and gets chafed/bumped around, many of the sharper edges will abrade. Of all the challenges for making humans live on the moon, sharp dust is one of the smaller ones.
    - 4y ago

ken47 4y ago

I find the title a little bit strange. Japan, the country, did not propose anything. Specific entities within Japan did. Perhaps I'm too post-nationalistic for this article's title.

senttoschool 4y ago
Same for any news out of China in the western media. It is as if people in the West thinks the entirety of China is united on every decision, invention that comes out of every entity in the country.
- Fatnino 4y ago
  More like, "comes through the country".
- meany 4y ago
  Doesn’t your remark make the same type of generalization about the West that you accuse the West of making about China.

deepdriver 4y ago

YouTuber Scott Manley has a great video on artificial gravity in space, including concepts that resemble the article's proposal: https://www.youtube.com/watch?v=nxeMoaxUpWk https://www.youtube.com/watch?v=nxeMoaxUpWk Before I watched the video, I didn't know the Soviet Union tested a (small) centrifuge for artificial gravity in space back in the 70s: https://en.wikipedia.org/wiki/Kosmos_782 https://en.wikipedia.org/wiki/Kosmos_782

yellowapple 4y ago

I feel like building this as a spinning ring (possibly inside a crater) makes more sense from a structural integrity standpoint (and possibly also a radiation shielding standpoint). Granted, lunar gravity probably makes structural integrity about ¹/₆ᵗʰ as hard to achieve as on Earth, but the spinning tower still seems a bit precarious.

ekianjo 4y ago

> Kyoto University partnered with construction company, Kajima Corp, So a university and a corp = Japan now. Wow. So next time Facebook partners with some academics, we can say "The US proposes..." ?

ekianjo 4y ago

Why does it have to be ON the moon though? An orbital station would rotate just the same, and if you are close enough to the moon you could still travel to the surface now and then for specific missions.

a5withtrrs 4y ago

Aren't there bigger issues...? Like no atmosphere protecting from radiation and things like space debris/projectiles?