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Yes, this is a fascinating topic; because although we know that 0.0G as in the International Space Station is unhealthy in many ways that 1.0G on Earth is not (

Yes, this is a fascinating topic; because although we know that 0.0G as in the International Space Station is unhealthy in many ways that 1.0G on Earth is not (1), the in-betweens are relatively unknown. e.g. How much of the health benefits of 1G do you get at 0.9 G? at 0.5G or 0.1G? Where's the inflection point? Would you still get the benefit if you rest in full gravity for 8 hours, and then move out of the ring section of a space station for the rest of the day? Would 1 hour per day in gravity do it? How would people's health be impacted by a long-term stay on the Moon (at 0.17G ) or Mars (0.38G) ? This is not well understood, and hard to study without more experimental data. Which would have to be gathered Off Earth. And we might need to know sooner or later. On the Moon you could do the Experiment on site, and bring people back on relatively short notice if it does not go well. But for Mars, if it doesn't work out there it's a long haul back, most of it at 0.0G. There have been proposals to build small spin rings in orbit to do the experiments on Astronauts, but these plans have not happened yet. (2) 1) https://davidson.weizmann.ac.il/en/online/sciencepanorama/dangers-zero-gravity https://davidson.weizmann.ac.il/en/online/sciencepanorama/da... https://pubmed.ncbi.nlm.nih.gov/11536970/ https://pubmed.ncbi.nlm.nih.gov/11536970/ https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_h... 2) https://en.wikipedia.org/wiki/Nautilus-X https://en.wikipedia.org/wiki/Nautilus-X

reaperman 3y ago
I also would be curious about effects of time spent at 1.1G, 1.5G, or 2G, including for those who grow up in it. > Would you still get the benefit if you rest in full gravity for 8 hours, and then move out of the ring section of a space station for the rest of the day? Would 1 hour per day in gravity do it? Again, curious if this is the case, would spending less time >1G but <2G be equivalent to spending larger amounts of time at 1G?
- m4rtink 3y ago
  At least thats something you can test on Earth using existing technology. IIRC the Soviets built centrifuges big enough to live in & did some longer term experiments, so there might already be some data available for this.
  - SideburnsOfDoom 3y ago
    Sadly you can't test alternating between 1G, and 0G daily, on Earth. Maybe that will be the answer. Or maybe the repeatedly changing gravity will really mess people up.
- SideburnsOfDoom 3y ago
  > would spending less time >1G but <2G be equivalent to spending larger amounts of time at 1G? The experiments need to be done, but my wild uninformed guess is: Human health is not math, the numbers won't stack up like "1.5G times 2 hours = 3 G-hours" Humans have evolved under 1.0G, all the way back the the ancestor who crawled up out of the sea around 400 million years ago. That's a long time with that as an environmental constant. Deviation from that environment in either direction, up or down, will have negative effects on the body. Some easy to predict, some less so.
dotnet00 3y ago
It's a huge shame the ISS's Centrifuge Accomodations Module never materialized. Obviously too small for humans, but would've still made it possible to study at least some animals between 0->1G
- rbanffy 3y ago
  Couldn’t we add a centrifuge inside a large inflatable? What could be the final size of the inflatable that could be fitted atop a cargo SLS to LEO or a Starship? One of the very good reasons not to do it is vibration and oscillation that would ruin some microgravity experiments.
  - SideburnsOfDoom 3y ago
    Yes, we could. Or rather, NASA could. But it hasn't a priority yet. Before going to Mars, the experiments will have to be done. Another way to try it out is: if people are healthy on the Moon's gravity for a long term, then Mars gravity is likely healthy too. So this says that in reality, going to Mars is not close, as neither of these experiments are immanent.

reaperman 3y ago

I also would be curious about effects of time spent at 1.1G, 1.5G, or 2G, including for those who grow up in it. > Would you still get the benefit if you rest in full gravity for 8 hours, and then move out of the ring section of a space station for the rest of the day? Would 1 hour per day in gravity do it? Again, curious if this is the case, would spending less time >1G but <2G be equivalent to spending larger amounts of time at 1G?

m4rtink 3y ago
At least thats something you can test on Earth using existing technology. IIRC the Soviets built centrifuges big enough to live in & did some longer term experiments, so there might already be some data available for this.
- SideburnsOfDoom 3y ago
  Sadly you can't test alternating between 1G, and 0G daily, on Earth. Maybe that will be the answer. Or maybe the repeatedly changing gravity will really mess people up.
SideburnsOfDoom 3y ago
> would spending less time >1G but <2G be equivalent to spending larger amounts of time at 1G? The experiments need to be done, but my wild uninformed guess is: Human health is not math, the numbers won't stack up like "1.5G times 2 hours = 3 G-hours" Humans have evolved under 1.0G, all the way back the the ancestor who crawled up out of the sea around 400 million years ago. That's a long time with that as an environmental constant. Deviation from that environment in either direction, up or down, will have negative effects on the body. Some easy to predict, some less so.

dotnet00 3y ago

It's a huge shame the ISS's Centrifuge Accomodations Module never materialized. Obviously too small for humans, but would've still made it possible to study at least some animals between 0->1G

rbanffy 3y ago
Couldn’t we add a centrifuge inside a large inflatable? What could be the final size of the inflatable that could be fitted atop a cargo SLS to LEO or a Starship? One of the very good reasons not to do it is vibration and oscillation that would ruin some microgravity experiments.
- SideburnsOfDoom 3y ago
  Yes, we could. Or rather, NASA could. But it hasn't a priority yet. Before going to Mars, the experiments will have to be done. Another way to try it out is: if people are healthy on the Moon's gravity for a long term, then Mars gravity is likely healthy too. So this says that in reality, going to Mars is not close, as neither of these experiments are immanent.