Why not? A pair of BA330s (to pick a well known example) around a central power and docking node would be ideal for a baton-type station. Solar arrays "hanging" from the node at 90 degrees to the two habitats. Radiator(s) from the fifth face of the central node. Docking adaptor on the sixth. Station would be rotating around the axis along the docking-adaptor/radiator line. By pivoting the solar arrays, you can actively counter any mass imbalance along the rotational axis, preventing tumble instabilities from building up.
The BA330 was designed for 0G environments, so if you want to use it for spin-gravity applications you'd have to do a lot of redesign - in which case it's no longer a BA330.
There's nothing inherent in inflatables that is incompatible with their use in spin-stations. (Quite the contrary, I suspect it will make many internal systems easier to develop.)
Quote from: Paul451 on 08/20/2017 05:40 amThere's nothing inherent in inflatables that is incompatible with their use in spin-stations. (Quite the contrary, I suspect it will make many internal systems easier to develop.)That I would agree with. Now we just need a rotating space station design that needs them.
Hardest thing to do will probably be dealing with some resonances along the cable to keep the structure stable, but that seems entirely doable to me.
Transit volume may also be important, not only transit time. If all you want to send are small number of dedicated astronauts, then let them deal with zero G. But if you want to send thousands of people and do it in relative comfort, as Musk intends to do, then spin gravity may be a logical thing to do.
Especially because I do not believe it is hard to do at all. Connect two ITS spaceships by a several hundred meters long cable(s), spin them up, and you have 1G gravity. Very little mass penalty needed, and no complex technology required. Hardest thing to do will probably be dealing with some resonances along the cable to keep the structure stable, but that seems entirely doable to me.
Quote from: mikelepage on 08/19/2017 07:30 amI voted not for Mars.Your design is intriguing. I see one major problem with it. How would any visiting spacecraft dock when there is no center location to attach to?
But the concept could be used for another design. My favorite though nobody seems to agree with me. Build a cylindrial station that rotates around a node at the center. Little volume at any given gravity. But along that cylinder all gravities from 0 to max are available for experiments. At the end two rigid or inflable habitats might be added to give more volume at max gravity.Some testing of different rotational speeds would be interesting. The limits presently set seem to accomodate sensitive persons immediately. It seems people do get adjusted to movement at sea over time. So with adjustment many people may be able to tolerate much higher rotation to achieve useful gravitation with smaller diameters.
Good catch. Yes, that gif is only about 1/3 of my full design, but I like putting it up to point out that being able to achieve a large(r) radius without tethers is possible without increasing mass significantly.
I'm attaching my modifications to Theodore Hall's excellent "comfort zone" chart.
Whatever the solution(s) is(/are), it's important to be able to test acceleration rate and angular velocity independently to get real-life data on the various boundaries of this chart.
Paul451, myself and others have debated on a number of occasions whether 4rpm is a useful limit to set, (it probably depends on the person as to how quickly they can adapt) but given that I think we can at least test 4rpm/Mars G using current/near future launch architectures, I'm inclined to only go above 4rpm if it we want to run higher gravity tests.
Quote from: mikelepage on 08/21/2017 05:20 amI'm inclined to only go above 4rpm if it we want to run higher gravity tests.My instincts say no for normal use, but it could be that people could tolerate it if need be - maybe with less moving around.
I'm inclined to only go above 4rpm if it we want to run higher gravity tests.
Which is why we need a testing platform, to confirm facts instead of relying on "instincts"...
Quote from: blasphemer on 08/20/2017 06:48 amEspecially because I do not believe it is hard to do at all. Connect two ITS spaceships by a several hundred meters long cable(s), spin them up, and you have 1G gravity. Very little mass penalty needed, and no complex technology required. Hardest thing to do will probably be dealing with some resonances along the cable to keep the structure stable, but that seems entirely doable to me.The ITS won't be designed for that. They are designed to be pushed up from the bottom, not suspended from the top. Completely different forces to deal with - going from compression to tension.
Quote from: Coastal Ron on 08/20/2017 03:40 pmQuote from: blasphemer on 08/20/2017 06:48 amEspecially because I do not believe it is hard to do at all. Connect two ITS spaceships by a several hundred meters long cable(s), spin them up, and you have 1G gravity. Very little mass penalty needed, and no complex technology required. Hardest thing to do will probably be dealing with some resonances along the cable to keep the structure stable, but that seems entirely doable to me.The ITS won't be designed for that. They are designed to be pushed up from the bottom, not suspended from the top. Completely different forces to deal with - going from compression to tension.You sure about that?
Something else to consider with the ITS though is that the human habitable levels are at the top, so the major effects of centripetal force in such an arrangement will be on the parts of the ITS that don't need to be tested. In order to feel simulated 1G of force for the occupied areas, the 2/3rd's of the ITS not occupied will likely have to be feeling above 1G forces, and the ITS may not be designed to handle that.
Given an ITS ship of 49.5m, if they were to attach two ITS ships nose to nose and spin during cruise phase, they could give the base of the crewed section (r~<20m) Mars gravity for only ~4.1rpm, and even then the uncrewed areas of the ITS ships would only achieve 93% of 1G at the most.
above 1G forces, and the ITS may not be designed to handle that.
Quote from: Coastal Ron on 08/22/2017 07:38 pmabove 1G forces, and the ITS may not be designed to handle that.The frame, tanks and engines are likely to be able to handle >1g, what with that whole "launching from Earth" thing.
Quote from: Paul451 on 08/23/2017 02:08 amQuote from: Coastal Ron on 08/22/2017 07:38 pmabove 1G forces, and the ITS may not be designed to handle that.The frame, tanks and engines are likely to be able to handle >1g, what with that whole "launching from Earth" thing.Launching applies compression forces, not tension. Suspending the ITS from a crane, or attaching two together and spin them, applies tension forces. Literally the bottom of the ITS is trying to separate from the top of the ITS.And of course when the ITS is on Earth and is being lifted back onto the launch pad it won't be fueled or loaded with cargo & people (i.e. "empty weight"), so any fuel, cargo or crew you add in space would reduce the amount of artificial gravity you could apply.However I have no doubt that a strong enough cable could be used (I'm a big fan of Dyneema), and I don't think there would be any vibration issues. That said, I think there are better ways to do the testing than spinning up two ITS...
56 bleeping years of manned spaceflight and the closest we've had to a single in-space test of AG is astronauts running around the deck of Skylab.
Is there any medical research on some drug to "disable" the vestibular system in a way that the brain ignores inbalance information?This is useless on earth because people would just drop to the ground without the balance information, but in zero-g it could work.
Launching applies compression forces, not tension.
Is there any medical research on some drug to "disable" the vestibular system in a way that the brain ignores inbalance information?This is useless on earth because people would just drop to the ground without the balance information, but in zero-g it could work. People would lose ability to "feel" attitude but perhaps visual cues would be enough.
You are taking into account that the whole ring is trying to fly apart, right? Each hinge has to be strong enough to hold the entire mass together, just like with a chain.
Love the design btw. Do you make the hinges strong enough to support the spinning vehicle, or do you add nuts and bolts after deployment?