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I'm trying to plan a rotating wheel space station for a project. It should be noted that I have to stay as close to real physics as possible, although it takes place in far future. The space station is orbiting an Earth-like planet.

The deck 0 is one with reactor core. Besides it's practically a one long tunnel to transport stuff from the manufacturing center to various sectors or to the docking bay.

The manufacturing center can be used to produce almost anything from food to spaceships (can't be bigger than maintenance tunnels). There is a constant supply with resources by a fleet of autonomous spacecraft, which mine asteroids and planets.

(additional notice): Power is not a problem here. Let's just assume there is a sufficient enough power source, which would be more than enough for most problems. Be it a nuclear reactor or thermonuclear one, doesn't matter.

And for everything else it's easier to show sketches. As I'm really bad at physics, I'm not sure if the station has some problems. Does it look feasible? Are there obvious and not-so-obvious problems? If so, what could be improved? space station map

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    $\begingroup$ I would suggest to add some thoughts, that are behind composition, why it's done that way and not another. As example there is some reason behind why production is outside at 1g and habitable area inside at 0.8g. Such description could make answers more useful for you, and easier for those who will answer. Why you do not use existing design for Space habitat's. It is possibly to build that way. You might like to take look at that channel Isaac Arthur for inspiration $\endgroup$ – MolbOrg Jul 31 '16 at 2:07
  • $\begingroup$ Ah, it's not a human space station. That explains 0.85g pretty well. 1g on the Deck 0 is a coincidence, which I didn't really plan. I'm aware of the existing designs, but, well, I'm designing my own one and not copying someone else. I used some of them for inspiration. $\endgroup$ – Elza Jul 31 '16 at 2:24
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    $\begingroup$ Perhaps you would like to consider an inner ring with less g force as manufacturing complex and research lab. That way some materials can be easily handled and I think I read it somewhere that it is easier to print materials in low g environment (3d printing?). $\endgroup$ – Hendrik Lie Jul 31 '16 at 2:45
  • $\begingroup$ Well, there is the Deck 2 with 0.42g, which is mostly empty right now and could be used for low g manufacturing. There is a room with <0.1g in the docking bay/hangars (not visible on the sketch, because it's further back) too, so Zero-g manufacturing (if it's needed) can be done there. But I didn't really hear anything about 3d-printing being easier in low g environment. I'll look into it, thanks. $\endgroup$ – Elza Jul 31 '16 at 2:57
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    $\begingroup$ One issue is that "reactor core" and "manufacturing" sound much heavier to me than "maintenance tunnels." In order for a rotating space station to work the centre of gravity has to be in the middle, which means the weight has to be more or less evenly distributed around the edge. $\endgroup$ – Nathaniel Jul 31 '16 at 5:30
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Welcome, Elza...! Your physics background is fine, you expressed the first key ingredient in true intelligence, you asked a question.
Your basic space station concept is sound, and has been the subject or central to fictional venues as diverse as '2001: A Space Odyssey' to ( think more what you're looking for) 'Star Trek Deep Space Nine'.
The concerns most likely to affect your product are around construction techniques and materials, Secondary only to the concerns of what will likely be a self-supporting environment. Use the wrong metal, or design ( think of a shipyard), and your structure doesn't hold up. Use the wrong or insufficient air/water/environmental controls, and it becomes unlivable. Good luck with you construction, your ideas, and with this place. SE is one of the most entertaining and educational places I have ever known..

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Is the core nontrotating? It doesn't appear to be, so docking will be tricky!

Big issue is shielding. How does it handle normal radiation and solar events?

Power?

With all this coming and going—you focused on distrubtion of goods—you’ll have to keep it ballanced.

You ought to be able to find detailed design discussions on line, and popular essays written over the past 50 years. You don’t have to invent from scratch! Wikipedia is a good place to start to find primary material referenced.

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  • $\begingroup$ No, the core rotates with the station. So, docking would involve synchronizing rotation with the station. Then the ship would be moved to one of four hangars. $\endgroup$ – Elza Jul 31 '16 at 2:26
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    $\begingroup$ That's not a good idea. You can spin the ship but can't make it orbit the center of the wheel. You'll hit the moving wall. $\endgroup$ – JDługosz Jul 31 '16 at 13:40
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    $\begingroup$ And yet it's common in the game Elite:Dangerous, which has plausible flight physics (excluding the various hand-wavy FTL systems). You only need to match the axis of rotation, then match the rotation, and you're done. $\endgroup$ – Useless Jul 31 '16 at 17:31
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    $\begingroup$ @JDługosz "ship would be moved" implies some kind of attachments, so ship moving away from the center shouldn't be a problem, as long as it is moved slowly enough so that the attachments (cables, grappling arms, whatever) can handle the forces, and as long as mass of the docking ship is small enough compared to the mass of the station that it doesn't cause too much wobble. $\endgroup$ – hyde Jul 31 '16 at 18:01
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    $\begingroup$ @JDługosz I'm not sure why would I want to orbit the center of the wheel. There is a large empty space in the center of the station, which the ship has to enter. It doesn't need to orbit anything. Once there it would be mechanically captured and docked. $\endgroup$ – Elza Jul 31 '16 at 18:03
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One thing I saw that concerned me that no one else has brought up yet is the location of the manufacturing area. Manufacturing in zero-G would probably be more efficient, so I would guess that it would be moved towards the center, with people on the outside.

Same with the power core. It is being subjected to stresses which it doesn't need to be subjected to. Gravity is useful to people because we evolved with it, but it's a pain for a lot of machinery.

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  • $\begingroup$ It could be done. It would mean an enlarged core of the space station, which is ok. However, it should be noted, however, that there is practically little space on the station with zero-g environment, because there are no static non-rotating parts, so the manufacturing would be in low-G instead of zero-G. As I commented somewhere else, one could use Deck 2 and the space behind the docking bay to manufacture critical elements in low-G and near-zero-G, while leaving the main manufacturing center on the Deck 0. As for the power core, yes, it would make sense. $\endgroup$ – Elza Jul 31 '16 at 18:55
  • $\begingroup$ @Elza less gravity also may make sense, not necessary zero. As example 1/3g will allow make 3 times more massive Si crystal's as example. Not huge improvement, but some improvement. 3 times more massive details in cnc lathe and so on. $\endgroup$ – MolbOrg Aug 2 '16 at 9:54
  • $\begingroup$ @MolbOrg I adjusted my sketch accordingly: made Deck 0 four times smaller, transferred power core and manufacturing center to the core of the station, which made the large lifts excessive. I'm not sure if it would make sense to update the question. $\endgroup$ – Elza Aug 2 '16 at 10:21
  • $\begingroup$ @Elza do not replace picture, but you might update question and put link to new picture(no the picture, but link only, and keep original picture as it is now) as current view for your station, but it is not necessary, but might be interesting. $\endgroup$ – MolbOrg Aug 2 '16 at 10:39
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As Nathaniel pointed out, you need to have weight distributed evenly. On larger scale, you can have manufacturing on 2 opposing segments and one backup core opposite the live one (or something else of similar weight, perhaps another (smaller/larger) manufacturing segment). You would probably also need some movable weights along entire structure to balance moving of heavy stuff through maintenance tunnels and to counter changes in layout and contents of rest of station. I hear water is pretty good radiation shield, and it can be pumped easily from one place to another, so parhaps you can use that as your weights. Have some layer of water at the outer edges of station (to keep some minimum shielding) and another layer of water that will be moved around as needed

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  • $\begingroup$ backup and movable blancing weight's, and water - good. $\endgroup$ – MolbOrg Jul 31 '16 at 14:02
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I'd get sick of watching the damn stars rotate and wobble all the time. It may seem silly but please put windows on the edge/floor so I can watch stars streak by in nice straight lines so I can imagine I'm going somewhere, even if I'm seeing the same stars every 34 seconds.

I'd hate to have to hang out in a maintenance tunnel to do this. Sure I can't sleep in 1g and work in .85g?

Windows are incredibly expensive to provide. Yet despite having camera and monitor technology for years we humans continue to install them on capsules, shuttles, and space stations. Before deciding they aren't needed because of technology x, be sure you understand why we keep installing them in the first place.

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  • $\begingroup$ that's alien station, so U would be there as saboteur, probably, so no sleep, humanity above everything else. $\endgroup$ – MolbOrg Jul 31 '16 at 3:38
  • $\begingroup$ I thought about it already. There are no windows. There are computer generated video streams on wall-displays, which are as good as windows. So, you wouldn't be bothered by wobbling and rotating stars. As for 0.85g… Astronauts sleep in microgravity environment, I don't see a particular reason for having sleep disorders because of 0.85g. I'm not sure if that would even be really noticeable. Btw, you don't have to work in 1g. Manufacturing is fully autonomous. $\endgroup$ – Elza Jul 31 '16 at 3:45
  • $\begingroup$ Sorry but if there are no windows I don't wanna go, even if I'm just a saboteur. $\endgroup$ – candied_orange Jul 31 '16 at 3:51
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    $\begingroup$ I like a view that never needs rebooting. $\endgroup$ – candied_orange Jul 31 '16 at 4:01
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    $\begingroup$ @Elza for that not-rebooting, I would add unpredictable in fine details by nature of its process. As child of chaos and order - I enjoy chaos in bottle, and it bothers me if it's not true chaos, so it might be predicted by a program. As biological order child, I prefer it(chaos) to be biological nature. Does not means that it's not livable conditions, but bigger station could help it to be more natural, but there will be lot's of people who do not care, and will be fine with your station, we are aesthetes here. $\endgroup$ – MolbOrg Jul 31 '16 at 4:33
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I see only a few problems with this design. The first is: Deck 0, and possibly other decks, don't have the correct calculated g-forces. If Deck 0 is 300m away from the center of rotation, and the station is rotating at 1.75rpm, the gravity at a point 300m away will be 10.0752m^2/s or 1.02739g.

However, the main problem that is seen with rotation space stations is scale. I don't know the size or biology of the inhabitants of this station, but if they were human, they might have the following problem:

At a distance of 293m away from the center, the centripetal acceleration is only 1.00341g, which is 0.02398g less than at 300m. In fact, the entire structure has an acceleration gradient over it.

If a human was standing in Deck 0, he might exhibit some rather serious health problems after a few minutes of standing. Because there is less force acting on his head than his feet, his heart will have to work harder to pump blood to his brain. I don't exactly know what the lethal gravitation gradient is, but I think it is a long-term effect of living in an artificial gravity scenario rather than an immediately deadly problem. It would also have relatively no effect if the inhabitant was prone (sleeping).

Again, I'm not sure what scale would be necessary to diminish this effect, but then again, I'm not sure if your potential inhabitants will have the same biological systems as humans.

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    $\begingroup$ Because there is less force acting on his head than his feet, his heart will have to work harder to pump blood to his brain. - not true, gradient works for up and down stream with equal force, no significant changes here. Second - standing human have same thing blood pressure in feet's is higher then in head - we are adapted for that. Ability to hang head down it unusual, and needs adaption - but still is possible at some extend. There is no problem with such gradient, even long therm ones, as I might see it, for perspective I have described. $\endgroup$ – MolbOrg Jul 31 '16 at 14:00
  • $\begingroup$ Gravitational gradient has more of an effect on comfort; if the heart can pump blood from the feet to the head against 1g all the way, it will actually find the task easier if gravity is reduced for some part of the blood's journey. $\endgroup$ – 2012rcampion Jul 31 '16 at 14:33
  • $\begingroup$ Never mind then, good to know. I still believe this would be a bigger comfort problem in a much smaller station, but now I'm convinced your station should be fine. Thanks for the correction guys. $\endgroup$ – Nathaniel D. Hoffman Jul 31 '16 at 18:07
  • $\begingroup$ Yes, I truncated/rounded some of the numbers inconsistently. It wouldn't, however, matter all that much. Other points were pointed by other people $\endgroup$ – Elza Jul 31 '16 at 20:44

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