I've got a different take here. I think the reason is that nobody has yet done the research needed to design a station. Reason is - physics is simple enough - but human bodies immensely complex. Nobody knows for sure what the effects would be of artificial gravity, or how much gravity we need - or what spin rates humans can tolerate and for how long.
Chances are, incidentally - early station is much more likely to be two space stations tethered to each other with a long tether, and then zero g research lab - and docking port - etc - at the hub.
I.e. might be like the ISS but some of the modules would be in zero g, some in partial gravity, some possibly in full g.
And joined together by inflated "tunnels" based on the idea of air beams.
There are lots of other ideas, including, adding a centrifuge sleeping compartment to the ISS.
But it's hard to motivate any of these without data to show what the effects would be - if anything indeed. Would they help with human health?
Optimists might say that even a small rotating station - perhaps similar size to the ISS - with low levels of artificial g (martian or even lunar g) might make a huge difference to health and comfort for the astronauts there - and that humans can tolerate high spin rates, perhaps 10 rpm or even higher.
Pessimists here could say that we probably need full gravity for it to be much value for human health and chances are many people can't even withstand 1 rpm.
Seems not such a big difference but for the same gravity, the size goes as the square. So if humans can withstand 10 rpm, then your space station is a hundredth of the size it would be if we can only withstand 1 rpm, and a thousandth of the size needed if it has to go down to, say, 0.1 rpm. Change from tens of kilometers to tens of meters.
So we can't do much to design a station until we know what the parameters are.
For some reason, nobody has ever tried to experiment in artificial gravity in space. Except a few experiments the Russians did with rats in a small centrifuge, which were promising but never followed up.
I'm not sure why that is. There are some easy experiments we could do almost right away. Way back before Apollo, with Gemini, they experimented with tethered spacecraft - only briefly, not spinning enough to get any artificial g that you'd notice - but showed the principle. And we've got quite a few tethered unmanned pairs of satellites for various reasons.
I think myself, that if we ever do have humans staying in space for longer than a year or two at a time, this may be the first step.
I wrote a few articles about this on my science20 blog which you might enjoy.
Chances are, incidentally - early station is much more likely to be two space stations tethered to each other with a long tether, and then zero g research lab - and docking port - etc - at the hub.
I.e. might be like the ISS but some of the modules would be in zero g, some in partial gravity, some possibly in full g.
And joined together by inflated "tunnels" based on the idea of air beams.
There are lots of other ideas, including, adding a centrifuge sleeping compartment to the ISS.
But it's hard to motivate any of these without data to show what the effects would be - if anything indeed. Would they help with human health?
Optimists might say that even a small rotating station - perhaps similar size to the ISS - with low levels of artificial g (martian or even lunar g) might make a huge difference to health and comfort for the astronauts there - and that humans can tolerate high spin rates, perhaps 10 rpm or even higher.
Pessimists here could say that we probably need full gravity for it to be much value for human health and chances are many people can't even withstand 1 rpm.
Seems not such a big difference but for the same gravity, the size goes as the square. So if humans can withstand 10 rpm, then your space station is a hundredth of the size it would be if we can only withstand 1 rpm, and a thousandth of the size needed if it has to go down to, say, 0.1 rpm. Change from tens of kilometers to tens of meters.
So we can't do much to design a station until we know what the parameters are.
For some reason, nobody has ever tried to experiment in artificial gravity in space. Except a few experiments the Russians did with rats in a small centrifuge, which were promising but never followed up.
I'm not sure why that is. There are some easy experiments we could do almost right away. Way back before Apollo, with Gemini, they experimented with tethered spacecraft - only briefly, not spinning enough to get any artificial g that you'd notice - but showed the principle. And we've got quite a few tethered unmanned pairs of satellites for various reasons.
I think myself, that if we ever do have humans staying in space for longer than a year or two at a time, this may be the first step.
I wrote a few articles about this on my science20 blog which you might enjoy.
- Can Spinning Habitats Solve Zero g Problem? And Answer Low g Questions?
- Could Spinning Hammocks Keep Astronauts Healthy in Zero g?
- Ingenious Idea: Soyuz Crew in Tether Spin On Way to ISS - For Artificial Gravity - Almost No Extra Fuel
- Crew Tether Spin - With Final Stage - On Routine Mission To ISS - First Human Test Of Artificial Gravity?
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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