4 ms·

And another thing: We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We don't know because we have spent the p

And another thing: We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We don't know because we have spent the past half a century fucking around with useless zero-g space stations instead of building von Braun wheels which could easily be used to simulate those conditions. Because forget about Mars colonization, merely finding the political willpower to do something as conceptually simple as spinning in space is evidently impossible for us.

bryanlarsen 1y ago
The simulation would be flawed. Von Braun wheels would have very significant Coriolis effects, so it'd be hard to distinguish whether any issues are due to reduced gravity or the Coriolis effects.
- lupusreal 1y ago
  Bone density and muscle loss effects shouldn't be significantly effected by coriolis effects. Such effects may likely cause nausea in many people, but it is very likely that test subjects who can adapt to it and live comfortably during the period of study could be found.
- PlunderBunny 1y ago
  My very rusty physics tells me that walking one way along the inside of the wheel would make you weigh less, and the other way would make you weigh more - is this what you're referring to? Would trying to work 'normally' in this kind of situation induce nausea, or make your food fall off your tray etc? It would be a shame if you went to all the effort to make a Von Braun wheel in space to simulate gravity, only to find that you had to stand still to do anything practical. (I assume the astronauts in 2001 A Space Odyssey jogged in the direction that made themselves weigh more, to make their workout more intense.)
  - Hemospectrum 1y ago
    Coriolis forces acting on the human vestibular system can directly induce motion sickness just from turning your head. If it turns out humans cannot acclimate through long term exposure, the only remedy is to increase the wheel radius.
- adrian_b 1y ago
  The Coriolis effects can be made to be mostly negligible, with a big enough wheel. A big wheel may be too costly, but it can be replaced by either 2 identical bodies with a long link between them, or with a single body linked to a counterweight, in which case the cost would be only marginally greater than for the current spaceships.
cubefox 1y ago
In several decades of zero-g research, they didn't even manage to put a few mice up to see whether they could successfully reproduce without gravity. Are they afraid of the results? It would be embarrassing if the mouse babies come out crippled, even if it doesn't immediately generalize to humans and the low-g environment of Mars.
- numpad0 1y ago
  They've successfully hatched small fish on ISS. For animals, IIRC embryos need gravity to determine heads and tails or something. We do already know. The answer is that we Earthian lives generally face great difficulty reproducing in zero-g.
  - cubefox 1y ago
    What exactly do we know? By the way, mice are far more similar to us than fish.
    - numpad0 1y ago
      I meant to say larger animals - it's been tried. Small fish and frogs were fine, but chicken eggs showed issues developing past some early stages under microgravity[1]. Therefore we know that animals significantly more complex than amphibians can not reproduce normally under zero-g. > Twenty out of 30 eggs (nine out of ten 10-day-old eggs; 10 out of ten 7-day-old eggs; 1 out of ten 0-day-old eggs) were recovered alive after landing. The only living embryo of the 0-day-old egg died 24 days after launch, and was comparable to a 16-day-old embryo when it died. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. The yolk (specific gravity, 1.029) would not have separated from the albumen (1.040) during space flight. 1: https://pubmed.ncbi.nlm.nih.gov/9600757/ https://pubmed.ncbi.nlm.nih.gov/9600757/ ( https://archive.is/r66W3 https://archive.is/r66W3 )
      - cubefox 1y ago
        Yeah. Another nice article on the bird experiments: https://finchwench.wordpress.com/2011/09/06/cosmoquails/ https://finchwench.wordpress.com/2011/09/06/cosmoquails/ Still, trying it with mice (or other mammals) would have been worth it, because we can't rule out mammals being more robust during embryogenesis than birds. The ISS actually has still a few years left, so there would be some time left for such an experiment. Though I doubt it will happen.
numpad0 1y ago
> We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We do know. The radiation kills us well before the lack of gravity does. The end. We have to have shieldings thick and heavy as nuclear bunkers for a real space station to work, and such shielding is just way too heavy to be launched from Earth(unless e.g. we'd be okay with launching a toilet stall worth of habitable volume per Starship), so the station has to be mostly fabricated "in space", which is both technically and politically not yet feasible. There are theories that horizontal branches that may exist in natural crevices on the Lunar surface might work. Or for Mars some say we can just drill some mineshafts there and live inside. but all those options are equally sketchy in its own ways at this moment. We're barely flying hatchbacks up to orbits and we want airport garages out there to park it. We're not hauling the whole building in the back of a Prius, not even on Earth, obviously. What NASA, ESA, etc. had been doing is to drive up that Prius to the trailer home left in the middle of the desert, have them change lightbulbs, celebrate themselves and rotate crews. That's basically useless, but they keep repeating that useless "expeditions" because they'll have to start over from reinventing tubeless wheels if they stop paying for the gas even just for one year.

bryanlarsen 1y ago

The simulation would be flawed. Von Braun wheels would have very significant Coriolis effects, so it'd be hard to distinguish whether any issues are due to reduced gravity or the Coriolis effects.

lupusreal 1y ago
Bone density and muscle loss effects shouldn't be significantly effected by coriolis effects. Such effects may likely cause nausea in many people, but it is very likely that test subjects who can adapt to it and live comfortably during the period of study could be found.
PlunderBunny 1y ago
My very rusty physics tells me that walking one way along the inside of the wheel would make you weigh less, and the other way would make you weigh more - is this what you're referring to? Would trying to work 'normally' in this kind of situation induce nausea, or make your food fall off your tray etc? It would be a shame if you went to all the effort to make a Von Braun wheel in space to simulate gravity, only to find that you had to stand still to do anything practical. (I assume the astronauts in 2001 A Space Odyssey jogged in the direction that made themselves weigh more, to make their workout more intense.)
- Hemospectrum 1y ago
  Coriolis forces acting on the human vestibular system can directly induce motion sickness just from turning your head. If it turns out humans cannot acclimate through long term exposure, the only remedy is to increase the wheel radius.
adrian_b 1y ago
The Coriolis effects can be made to be mostly negligible, with a big enough wheel. A big wheel may be too costly, but it can be replaced by either 2 identical bodies with a long link between them, or with a single body linked to a counterweight, in which case the cost would be only marginally greater than for the current spaceships.

cubefox 1y ago

In several decades of zero-g research, they didn't even manage to put a few mice up to see whether they could successfully reproduce without gravity. Are they afraid of the results? It would be embarrassing if the mouse babies come out crippled, even if it doesn't immediately generalize to humans and the low-g environment of Mars.

numpad0 1y ago
They've successfully hatched small fish on ISS. For animals, IIRC embryos need gravity to determine heads and tails or something. We do already know. The answer is that we Earthian lives generally face great difficulty reproducing in zero-g.
- cubefox 1y ago
  What exactly do we know? By the way, mice are far more similar to us than fish.
  - numpad0 1y ago
    I meant to say larger animals - it's been tried. Small fish and frogs were fine, but chicken eggs showed issues developing past some early stages under microgravity[1]. Therefore we know that animals significantly more complex than amphibians can not reproduce normally under zero-g. > Twenty out of 30 eggs (nine out of ten 10-day-old eggs; 10 out of ten 7-day-old eggs; 1 out of ten 0-day-old eggs) were recovered alive after landing. The only living embryo of the 0-day-old egg died 24 days after launch, and was comparable to a 16-day-old embryo when it died. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. The yolk (specific gravity, 1.029) would not have separated from the albumen (1.040) during space flight. 1: https://pubmed.ncbi.nlm.nih.gov/9600757/ https://pubmed.ncbi.nlm.nih.gov/9600757/ ( https://archive.is/r66W3 https://archive.is/r66W3 )
    - cubefox 1y ago
      Yeah. Another nice article on the bird experiments: https://finchwench.wordpress.com/2011/09/06/cosmoquails/ https://finchwench.wordpress.com/2011/09/06/cosmoquails/ Still, trying it with mice (or other mammals) would have been worth it, because we can't rule out mammals being more robust during embryogenesis than birds. The ISS actually has still a few years left, so there would be some time left for such an experiment. Though I doubt it will happen.

numpad0 1y ago

> We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We do know. The radiation kills us well before the lack of gravity does. The end. We have to have shieldings thick and heavy as nuclear bunkers for a real space station to work, and such shielding is just way too heavy to be launched from Earth(unless e.g. we'd be okay with launching a toilet stall worth of habitable volume per Starship), so the station has to be mostly fabricated "in space", which is both technically and politically not yet feasible. There are theories that horizontal branches that may exist in natural crevices on the Lunar surface might work. Or for Mars some say we can just drill some mineshafts there and live inside. but all those options are equally sketchy in its own ways at this moment. We're barely flying hatchbacks up to orbits and we want airport garages out there to park it. We're not hauling the whole building in the back of a Prius, not even on Earth, obviously. What NASA, ESA, etc. had been doing is to drive up that Prius to the trailer home left in the middle of the desert, have them change lightbulbs, celebrate themselves and rotate crews. That's basically useless, but they keep repeating that useless "expeditions" because they'll have to start over from reinventing tubeless wheels if they stop paying for the gas even just for one year.