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I didn't see any mention of having a spinning surface. A tapered cylinder "gravity gym" with adjustable angled walls, and variable speed spinning, could smooth

I didn't see any mention of having a spinning surface. A tapered cylinder "gravity gym" with adjustable angled walls, and variable speed spinning, could smoothly create much greater "gravity". Spin gravity would also enable body weight exercises, core exercises, stationary or small area cardio like exercise bikes, VR games, yoga, etc. Even sleeping. EDIT: I missed this: > but Moon-based centrifuges allowing locomotion inside would pose technical challenges Still think it will be inevitable. Far more useful physically and psychologically. "Spinning surface" is a simple challenge, compared to "low-g health deterioration" and "bored to death of running in circles". Equipment like this might resolve issues with off-world childbearing. Time to "spin up" some space rabbits and see what we get! (Hopefully not tribbles.) Spin areas will surely become ubiquitous in all low gravity colonies. Startup anyone?

fallingsquirrel 3y ago
You probably know this already, but for a while people were toying with the idea of a "childbirth centrifuge". https://patents.google.com/patent/US3216423A/en https://patents.google.com/patent/US3216423A/en There's probably a reason it never caught on.
- Nevermark 3y ago
  Reason one - We already have gravity here. Reason two - Childbirth + vertigo? WTF! Clearly they should have gone with a rudimentary linear accelerator such as a bungy drop or bouncing elevator type system!
  - antonvs 3y ago
    > Clearly they should have gone with a rudimentary linear accelerator Like a railgun.
  - estebank 3y ago
    While on the subject of inventions to aid with childbirth, I'll leave this here: https://science.howstuffworks.com/science-vs-myth/everyday-myths/why-were-chainsaws-invented.htm https://science.howstuffworks.com/science-vs-myth/everyday-m...
- duskwuff 3y ago
  Also the subject of an opera. http://www.henryakona.com/the_blonsky_device.html http://www.henryakona.com/the_blonsky_device.html
kyleyeats 3y ago
You know you have to fly all this stuff up there, right? You can dig out one of these pits with a shovel.
- Nevermark 3y ago
  Self-sufficiency off-world is going to be much easier if people are healthy and happy. A "gravity gym" is going to be basic healthcare. Wherever we go for the long term, we will ship and/or construct them.
  - maxerickson 3y ago
    Yeah, that's what they said, a self sufficient way of constructing a gravity gym.
  - usrusr 3y ago
    Separate facilities for work and life, interconnected by a rollercoaster commute. What else has sci-fi left out?
hedora 3y ago
I assume they’ll eventually just build a big gravitron. The seals would be tricky (I guess the axle it spun on could contain a ladder and door?) Of course they could simply stop spinning it whenever they needed to open an airlock. (Or just put it in orbit, where these problems are easier to deal with and you don’t need to deal with day/night radiation shielding/heating.)
- wongarsu 3y ago
  Spin gravity in orbit has its own issues. Most notably you can't anchor the structure anywhere, so won't spin around the spin axis you want but around its center of mass. A center of mass that will shift as people move around, equipment is moved, etc. Another issue is that you need a certain scale, otherwise the Coriolis force as well as differential gravity (the gravity at your feet being higher than that at your head) lead to disorientation and comfort issues. The lower limit seems to be about 40 feet, incidentally the size of a typical graviton on carnival on earth. That's quite a bit wider than the typical rocket, and for now we are much more comfortable with assembling stuff in a gravity well than in orbit.
  - WalterBright 3y ago
    > That's quite a bit wider than the typical rocket You can have two habitats connected by a center tube, like an I. Rotate about the center of the I. Or a habitat and a cable connected to a counterweight. It's not really necessary to build a wheel.
    - estebank 3y ago
      In orbit, you don't even need the tube, it can be a single habitat with retractable cables attached to a counterweight of useful material that isn't immediately needed.
  - dr_dshiv 3y ago
    It could be a blown up multiwalled sphere with the heavy equipment in a solid cylinder in the middle. The walls would naturally be a bit bouncy, if under the pressure of the internal air. A big arena for playing professional sports could make a significant amount of money through televised sporting events.
aaron695 3y ago
[dead]
Galatians4_16 3y ago
On the Moon, at normal pressure, humans shoud be able to get enough exercise in a jungle gym, or by donning a set of wings, flapping them to fly.
- Cthulhu_ 3y ago
  Given that there is some gravity, putting on a weighted suit to increase their mass would also make sense, although it'd be unwieldy if it's not distributed exactly the same. Plus, getting weight into space is expensive... although probably not as expensive as building a wall of death or spin gravity structure.
  - scotty79 3y ago
    Why wall of death? It's gonna be just a neat cylindrical room with vaguely paraboloid walls. Even if you stop running suddenly, dropping down from 2-3 meters in 1/6 g shouldn't be anything more than inconvenient. Weighted suit wouldn't help with the weight of your organs. They are accustomed to hanging inside you at 1g. Running on wall would provide them with that.
    - heleninboodler 3y ago
      > Why wall of death? I think that's just what the cylindrical room is often called when it's used for motorcycles. The paper repeatedly references it, abbreviated "WoD." I don't think there's any death involved. :)
    - persolb 3y ago
      I was going to say “I’d be surprised if organ support is a large issue to an adult. We already have long term astronauts and people who are bed ridden for a long time during recovery. I would expect an issue during development though.” Turns out there is research in this direction: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2379624/pdf/canfamphys00112-0142.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2379624/pdf/can... It seems to say that there is a long term impact on connective tissue hardening… but it blames lack of stretching; not lack of downward force. Any regular movement would seem to fix that. However, internally, organ tissue probably ‘bounces’ more due to gravity during movement… so less gravity means less flex of connective tissue. TLDR: you seem to be right
TheDudeMan 3y ago
It's easier in space. I suspect it will happen there first and predominantly.
jillesvangurp 3y ago
Wild idea: build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. That would likely be something that fitness people and professional athletes would be interested in. And it's a good dry run for building and operating these things on Mars and the Moon. If we can make these things work on Earth, making them work in lower gravity is only going to be easier as the g-forces would be lower. A train or roller coaster on a slightly tilted circular track would probably do the job. A slight tilt would just move the gravity vector orthogonal to the floor.
- yjftsjthsd-h 3y ago
  > build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. Is that any better than ankle weights? Or wrist, I suppose.
  - jjk166 3y ago
    The difference between weights on your body and higher gravity field is that with higher gravity all of you feels the force equally at the same time, so you're not putting excessive strain on certain parts of your body while neglecting others (such as internal structures).
- amstan 3y ago
  Why did nobody do this yet? It would totally be a great prototype for stuff in orbit.
  - Cthulhu_ 3y ago
    Closest thing I can think of is rotating houses / restaurants, but they go very slowly. It would have to be big enough to avoid people getting dizzy, and even then it would still be a factor I think. That said, size/scale is less of a concern on the moon I would argue.

fallingsquirrel 3y ago

You probably know this already, but for a while people were toying with the idea of a "childbirth centrifuge". https://patents.google.com/patent/US3216423A/en https://patents.google.com/patent/US3216423A/en There's probably a reason it never caught on.

Nevermark 3y ago
Reason one - We already have gravity here. Reason two - Childbirth + vertigo? WTF! Clearly they should have gone with a rudimentary linear accelerator such as a bungy drop or bouncing elevator type system!
- antonvs 3y ago
  > Clearly they should have gone with a rudimentary linear accelerator Like a railgun.
- estebank 3y ago
  While on the subject of inventions to aid with childbirth, I'll leave this here: https://science.howstuffworks.com/science-vs-myth/everyday-myths/why-were-chainsaws-invented.htm https://science.howstuffworks.com/science-vs-myth/everyday-m...
duskwuff 3y ago
Also the subject of an opera. http://www.henryakona.com/the_blonsky_device.html http://www.henryakona.com/the_blonsky_device.html

kyleyeats 3y ago

You know you have to fly all this stuff up there, right? You can dig out one of these pits with a shovel.

Nevermark 3y ago
Self-sufficiency off-world is going to be much easier if people are healthy and happy. A "gravity gym" is going to be basic healthcare. Wherever we go for the long term, we will ship and/or construct them.
- maxerickson 3y ago
  Yeah, that's what they said, a self sufficient way of constructing a gravity gym.
- usrusr 3y ago
  Separate facilities for work and life, interconnected by a rollercoaster commute. What else has sci-fi left out?

hedora 3y ago

I assume they’ll eventually just build a big gravitron. The seals would be tricky (I guess the axle it spun on could contain a ladder and door?) Of course they could simply stop spinning it whenever they needed to open an airlock. (Or just put it in orbit, where these problems are easier to deal with and you don’t need to deal with day/night radiation shielding/heating.)

wongarsu 3y ago
Spin gravity in orbit has its own issues. Most notably you can't anchor the structure anywhere, so won't spin around the spin axis you want but around its center of mass. A center of mass that will shift as people move around, equipment is moved, etc. Another issue is that you need a certain scale, otherwise the Coriolis force as well as differential gravity (the gravity at your feet being higher than that at your head) lead to disorientation and comfort issues. The lower limit seems to be about 40 feet, incidentally the size of a typical graviton on carnival on earth. That's quite a bit wider than the typical rocket, and for now we are much more comfortable with assembling stuff in a gravity well than in orbit.
- WalterBright 3y ago
  > That's quite a bit wider than the typical rocket You can have two habitats connected by a center tube, like an I. Rotate about the center of the I. Or a habitat and a cable connected to a counterweight. It's not really necessary to build a wheel.
  - estebank 3y ago
    In orbit, you don't even need the tube, it can be a single habitat with retractable cables attached to a counterweight of useful material that isn't immediately needed.
- dr_dshiv 3y ago
  It could be a blown up multiwalled sphere with the heavy equipment in a solid cylinder in the middle. The walls would naturally be a bit bouncy, if under the pressure of the internal air. A big arena for playing professional sports could make a significant amount of money through televised sporting events.

aaron695 3y ago

[dead]

Galatians4_16 3y ago

On the Moon, at normal pressure, humans shoud be able to get enough exercise in a jungle gym, or by donning a set of wings, flapping them to fly.

Cthulhu_ 3y ago
Given that there is some gravity, putting on a weighted suit to increase their mass would also make sense, although it'd be unwieldy if it's not distributed exactly the same. Plus, getting weight into space is expensive... although probably not as expensive as building a wall of death or spin gravity structure.
- scotty79 3y ago
  Why wall of death? It's gonna be just a neat cylindrical room with vaguely paraboloid walls. Even if you stop running suddenly, dropping down from 2-3 meters in 1/6 g shouldn't be anything more than inconvenient. Weighted suit wouldn't help with the weight of your organs. They are accustomed to hanging inside you at 1g. Running on wall would provide them with that.
  - heleninboodler 3y ago
    > Why wall of death? I think that's just what the cylindrical room is often called when it's used for motorcycles. The paper repeatedly references it, abbreviated "WoD." I don't think there's any death involved. :)
  - persolb 3y ago
    I was going to say “I’d be surprised if organ support is a large issue to an adult. We already have long term astronauts and people who are bed ridden for a long time during recovery. I would expect an issue during development though.” Turns out there is research in this direction: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2379624/pdf/canfamphys00112-0142.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2379624/pdf/can... It seems to say that there is a long term impact on connective tissue hardening… but it blames lack of stretching; not lack of downward force. Any regular movement would seem to fix that. However, internally, organ tissue probably ‘bounces’ more due to gravity during movement… so less gravity means less flex of connective tissue. TLDR: you seem to be right

TheDudeMan 3y ago

It's easier in space. I suspect it will happen there first and predominantly.

jillesvangurp 3y ago

Wild idea: build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. That would likely be something that fitness people and professional athletes would be interested in. And it's a good dry run for building and operating these things on Mars and the Moon. If we can make these things work on Earth, making them work in lower gravity is only going to be easier as the g-forces would be lower. A train or roller coaster on a slightly tilted circular track would probably do the job. A slight tilt would just move the gravity vector orthogonal to the floor.

yjftsjthsd-h 3y ago
> build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. Is that any better than ankle weights? Or wrist, I suppose.
- jjk166 3y ago
  The difference between weights on your body and higher gravity field is that with higher gravity all of you feels the force equally at the same time, so you're not putting excessive strain on certain parts of your body while neglecting others (such as internal structures).
amstan 3y ago
Why did nobody do this yet? It would totally be a great prototype for stuff in orbit.
- Cthulhu_ 3y ago
  Closest thing I can think of is rotating houses / restaurants, but they go very slowly. It would have to be big enough to avoid people getting dizzy, and even then it would still be a factor I think. That said, size/scale is less of a concern on the moon I would argue.