space station with artificial gravity, can it be done cheap?

jurgens · May 15, 2005

ohh, that too.

mental_avenger · May 15, 2005

I think spin-gravity is overrated, it means heavier structures to handle the loads, complications on docking (axially isn't too bad), serious complications on orbital manoevering[sic] etc. If you are talking about a relatively useless ISS type station, you might have a point. I don’t’ think that is what is being discussed here. A really useful space station would require artificial gravity (Grav). Consider Station 5 from 2001: A Space Odyssey as an example of a viable space station. It would have everything needed for long term habitation of the onboard personnel, service of vehicles leaving Earth and returning to it, and recreation for everyone. Agreed, attempting to use STS for a rotating space station would not work, but building a REAL space station from scratch would. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

ve7rkt · May 15, 2005

You know, there could be something to this. My problem with docking the way the Orion docked to Station V is that for a station like that, only being able to dock one (maybe two, if there's a dock on the far side) craft could be a problem... maybe not for something as 'small' as Station V, but certainly if we ever build something like a Stanford Torus. The traditional solution is a counterrotating hub, but then you have to deal with having rotating sections of your pressurized space, which means funky seals... well, instead, make what amounts to a railway track on the inner edge of the wheel. On this track you put a sled. When you're expecting a shuttle, you run the sled opposite the station's rotation so as far as the shuttle is concerned, the sled is stationary. The shuttle gently parks itself on the sled in microgravity. Once the shuttle is clamped or tied down, the sled puts on the brakes, which will start it rotating along with the station, and the shuttle will then experience the station's artificial gravity. The sled can travel over to an airlock-hangar or position itself over a docking port. When it's time to leave, the sled travels against the station's rotation again, and the shuttle can just drift away. One way to look at it is a landing pad where you can turn the gravity on and off. It's not, really, but you can think of it that way. I'm not sure how sliding a mass like that around the spinning station might cause the station to wobble, though.

frodo1008 · May 15, 2005

ve7rkt: Please remember that if you are talking about a stanford torus the inner hub itself would be some 100 meters in diameter. This is plenty large enough to have many docking ports. However, we are a long way from this size of space infrastructure. We would have to be not only exploring the moon, but also actually exploiting the moon's resources before such large structures could even be contemplated. However, a rotating type of space station with both the gravity of the moon (say at a very mild 2 rpm at a gravity of 0.17 g) would have a diameter of some 235 feet, and for Martian gravity of 0.38 (again at 2 rpm) a diameter of some 536 feet. This would indeed be a very large station! Just for comparison: using 1.0 g (Earth normal) and 2 rpm the diameter would have to be some 1500 feet. So for Earth normal you are approaching the size of a small stanford torus itself. I fully believe that the next space station should be located in a more accessible orbital inclination at from 500 to 1,000 miles altitude. Such a station is necessary as we really do not know any more about possible adverse affects of long term living at such low gravities as the moon or Mars than we originally did about zero gravity’s adverse affects. Before long term stays in zero gravity stations (Mir and ISS) we did not know anything about the long-term adverse affects of staying at zero gravity either!! Now we know there are indeed such long term adverse affects that we now want to keep such trips as to the outer planets to a minimum time for humans or spin the ships themselves to obtain artificial gravity. Also, such a station could not only be used for research, but would itself be the basis for a destination for early space tourism. This would be much more desirable than a pure zero gravity destination as we already know that some 33% of all astronauts experience space sickness, and these are highly trained people!! There is a vast difference in a s

grooble · May 16, 2005

Can't you just use magnets on the walls and have the guys wear special suits, so it sort of simulates weight? The bottom magnets pull, why the top magnets push down?

mrmorris · May 16, 2005

"Can't you just use magnets..." The point of gravity, or a simulation thereof is that it affect the entire body (i.e. every molecule that makes it up). Magnets may push someone to the 'floor', but it won't provide the level of orientation that a rotating station would via inertia. In fact -- it won't do anything whatsoever to mitigate the physiological effects of weightlessness.

grooble · May 16, 2005

Would it provide easier working and living conditions though?

mrmorris · May 16, 2005

"Would it provide easier working and living conditions though?" Would it? Personally, I doubt it. However, having never worked in zero-G -- I'm not the best source for an answer to that question. My post was to demonstrate that it would *not* solve the number one issue with Zero-G. It's the physiological problems that drive the push towards artificial gravity. Having strong magnetic fields throughout the station would also wreak havoc with equipment, computers, etc. -- so even if there were some benefit to working conditions -- it would not come without cost.

frodo1008 · May 16, 2005

grooble: Are you that dead set against rotating stations? I agree with mrmorris that using magnets would be a stop-gash type of solution at best, and at worse more problems than it would solve. Another more long range reason for using spin to generate artificial gravity is that if we are ever going to really exploit (as opposed to just explore) space we are going to have to learn to have relatively large numbers of people living and working in space. Partial gravity artificially generated by spinning stations, or even in the farther long range colonies (all the way up to 1.0 g) is going to be the only way that this kind of effort is going to be done. We might as well get on with it with smaller efforts now!!

grooble · May 16, 2005

The interesting thing about these subjects is that once you solve the problem, you've solved it forever and the tech will be used for the rest of our spacefaring history, and improved upon.

CalliArcale · May 16, 2005

<blockquote>In reply to:<hr />My post was to demonstrate that it would *not* solve the number one issue with Zero-G. It's the physiological problems that drive the push towards artificial gravity. Having strong magnetic fields throughout the station would also wreak havoc with equipment, computers, etc. -- so even if there were some benefit to working conditions -- it would not come without cost.<hr /></blockquote> That's a good point about the computers. One other point is that it would actually help mitigate *some* of the problems of weightlessness. Mainly, it would give you some exercise. That does help with the bone loss and muscle loss and weakening of cardiac tissue. But it wouldn't be perfect, you're right, and fluid loading would be pretty much unaffected; your body fluids will still act weightless. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

odysseus145 · May 16, 2005

>>fluid loading would be pretty much unaffected; your body fluids will still act weightless. Why is that? <div class="Discussion_UserSignature"> </div>

drwayne · May 16, 2005

They are insufficiently magnetic to react in any meaningful way to any resonable magnetic field. Wayne <div class="Discussion_UserSignature"> "1) Give no quarter; 2) Take no prisoners; 3) Sink everything." Admiral Jackie Fisher </div>

scottb50 · May 16, 2005

So nobody likes my idea? I guess I forgot the arrows to show rotation. If you figure each module is 60 feet in length and 30 feet in diameter the outer Modules would be 90 feet from the center of the assembly. If you spin them around the central Module you could have whatever gravity desired in the outer Modules by varying the rotation speed. Add four or eight Modules and extend the arm out another sixty feet and the rotation could be slower. As long as the Module integrity is sufficient any number could be used. If you are using the radial Modules for storage and the outer Modules for crew and passenger facilities it would be easy to have a transfer system down the center of the Modules, a smaller Module withing the Module. Climb up to, or use an elevator, to the central Module, where you would have zero G and then down into the other outer Modules, gravity decreases as you get lower and the central MNodule(s) would be in zero G. If you figure each core Module could attach two or four radial Modules and you could add as many other similar stacks to create a vehicle you would have ultiment flexibility in assembling a transit vehicle. <div class="Discussion_UserSignature"> </div>

bobvanx · May 16, 2005

I've always been bothered by the need for a seal at a counter-rotating hub, too. Now it occurs to me that it needn't be pressurized. Your space taxi docks with a mechanical contact on a counter-rotating spindle, and then that contact rides a short track to the pressurized volume, where the real docking then takes place. The issue is we want to separate the capture event from hooking up the harddocks. So we perform a capture at a "non rotating" member of the station using thrusters, and then transfer to the rotating section mechanically. And keep the mass of the taxi near the hub, to minimize wobbling.

scottb50 · May 16, 2005

I would think it simpler to use a clutch type system. A stationary Docking Port, once the docking is achieved it engages, if it is in the central Module gravity is not a problem.. <div class="Discussion_UserSignature"> </div>

spacefire · May 16, 2005

what would it take to build an automatic docking system to match the rotation of the incoming shp with that of a space station? <div class="Discussion_UserSignature"> http://asteroid-invasion.blogspot.comhttp://www.solvengineer.com/asteroid-invasion.html </div>

scottb50 · May 16, 2005

Why bother? A stationary Docking Adapter with a clutch mechanism would work just fine. Dock directly, engage the clutch, as long as you are at the hub it would make very little difference. <div class="Discussion_UserSignature"> </div>

mental_avenger · May 17, 2005

Even without seals, a counter-rotating section would be extra expense, extra mass, and yet another potential set of problems. A clutch would only add to all that. Really, there is no need for the rotating section. As Frodo pointed out, the large central hub area would be plenty large enough to dock many vessels. A large station would rotate slowly, and it would probably not be difficult to design a docking system that allowed docking while rotating. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

ve7rkt · May 17, 2005

As Frodo pointed out, the large central hub area would be plenty large enough to dock many vessels. A large station would rotate slowly, and it would probably not be difficult to design a docking system that allowed docking while rotating. Problem is, if the hub is rotating along with the rest of the station, any docking port not actually on the axis is moving in a circle around the axis. You can have no more than two docking ports, one on either end of the hub, no matter how large the hub is... UNLESS the hub counterrotates to appear stationary while the rest of the station spins, in which case you can stick on as many docking ports as you have room for.

CalliArcale · May 17, 2005

I personally like the idea of a despun section for docking. There is one vehicle that has actually had both spun and despun sections -- the Galileo spacecraft. The spun section continually swept the magnetometer booms while the despun section carried the instrumentation requiring a steady base (such as the cameras). This gave it the unique ability to take pictures and magnetometer readings simultaneously. It was very expensive, though, and no subsequent spacecraft has been given this capability. Although it's a cool concept and definitely useful, it remains to be seen whether it would be practical in terms of budget. Unfortunately, that's the killer for most neat concepts. <img src="/images/icons/frown.gif" /> <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

holmec · May 17, 2005

I beg you pardon. The way that 2001 did docking is a crude way. I have taken that and expoouded on it. And I have only take basic physics, but with the physics I know I come up with this stuff. Its just a matter of haveing a nack of finding new ways of doing things in order to find the best. The big problem with 2001 docking, is that it only allowed for one vehicle. My idea allows for an airport like operation. <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

holmec · May 17, 2005

are you making the rim out of paper?? You design a proper supporting runway. <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

holmec · May 17, 2005

>b) require too much thrust< What thrust? The ship, with a landing gear comes in, hits the runway, and starts accelating backwards with the rotation of the station. No thrust required, just breaks. And launch couldn't be simpler, use the rotaion of the station to just let go of the ship and it flies off with an velocity and without thrusters. I think you are assuming that you have to get the ship up to speed before landing. I have taken the opposite approach. Let the rotation of the station speed up the ship. What physics are you studying, JurgenS? <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

exoscientist · May 17, 2005

I've been puzzling over the origin of the effect discussed here: David Swenson's electrostatic "invisible wall". http://amasci.com/weird/unusual/e-wall.html It concerns the creation of an "invisible wall" due to electrostatic charge from a large sheet of polypropelene film moving at high speed at a 3M plant. Such a force due to electrostatic charge should exist on water or anything containing water, but I'm still puzzling over why the force was repulsive rather than attractive. See the discussion here: Newsgroups: sci.astro, sci.physics, sci.engr.mech, sci.space.policy, sci.chem From: "Robert Clark" <rgregorycl...@yahoo.com /> Date: 10 May 2005 10:30:30 -0700 Local: Tues,May 10 2005 1:30 pm Subject: Re: An "invisible wall" for ground-based scopes.[Re: An atmospheric envelope for ground-based telescopes.] http://groups-beta.google.com/group/sci.physics/msg/6f4702425637594d Nevertheless, whether the effect is attractive or repulsive it could still be used for artificial gravity. Bob Clark <div class="Discussion_UserSignature"> </div>

space station with artificial gravity, can it be done cheap?

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