Alternatives To Rotating Sections For Artificial Gravity?
- Thread starter Knight Templar
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The design is a concept and it serves to make a point. I think it does it well. The point is that you could build a space ship that feels like the Enterprise on the inside and on the outside, and that you could do it right now. If someone actually starts building something, then we'd worry about how complicated it is. I think nobody would disagree that dropping the asymmetric parts, especially the nacelles, is a good idea.
On the contrary. Using counterrotating sections is a standard idea when it comes to proposed designs for space habitats or vessels that incorporate rotating sections. A habitat rotating in only one direction would have a gyroscope effect that would make it difficult to turn its axis, but it would need to be able to precess its axis to keep solar panels, windows, mirrors, etc. properly aligned with the Sun. So a standard solution is to build two adjacent counterrotating habitats and link them physically, so their angular momentum cancels out and there's no resistance to precession. It's got nothing to do with "mak[ing] it look like a fictional ship" -- it's just a good idea for any space dwelling that incorporates a rotating section.
This means that to get to my girlfriend working one meter away from me (give or take one kilometer), I've got to take the turbolift to travel one Taipei 101 uo, and then take another turbolift to go one Taipei 101 down. That, or perform the space equivalent of jumping off a moving car from an unpressurised platform on the top floor.
I like it.
I like it.
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TerraNovan
Lieutenant Commander
lol just like you have to do when your going between buildings that are side by side.
Anyhow I'll never understand what is so complicated with using rotational forces to make gravity. The earth rotates the sun all the time, if it didn't we'd collide with it, the same with the moon. It's a failure of science fiction, for this idea not to be commonplace after all this time.
I've never been given a good reason while rotational forces are the best form of gravity.
It doesn't need to be a wheel either, ignoring atmosphere issues you could suspend two houses together by a tether and have simulated gravity in your own home.
I have no idea what you're saying here. The Earth's revolution around the Sun (rotation is what it does about its own axis, revolution what it does around the Sun) has nothing to do with its gravity, which is generated by its own mass exerting gravitational force.
Although the physics of planetary orbit are related to the physics of artificial rotational "gravity." It's not real gravity, of course, but it's an outward acceleration. Planets stay in orbit because that outward rotational acceleration (and yes, it is outward within the rotating observer's frame of reference) balances the inward pull of the Sun's gravity.
Well, actual gravity, the force of attraction between masses, is so weak that it takes an enormous amount of mass to produce a significant pull. And that's prohibitively impractical for a constructed space habitat or vessel. So you need some other form of acceleration to create weight. Engine thrust could do the job; as Einstein's principle of equivalence showed, being in a rocket thrusting "upward" at 1g would feel identical to being on the Earth's surface with gravity pulling downward at 1g. But thrust requires fuel, and thrust at any significant fraction of 1g would burn up a lot of fuel very fast. It would be a short-term solution at best. And it certainly wouldn't be an option for a space station.
So what you need is a source of continuous, constant acceleration that doesn't expend fuel, and that's what rotation provides. Once you get a habitat spinning, its own angular momentum keeps it going, as long as there's no friction to slow it down. So rotation is really the only practical long-term option.
The problem is that superficially it may look like the Enterprise on the outside, but on the inside it won't look or feel anything like the Enterprise. Trying to force the function to follow the form really compromises the thing.
Thanks for the refresher Christopher, but in the end a counter rotating section is not necessary if your not trying to shoehorn it into a fictional ship design. It does add to the complexity of the design in this situation all in the name of aesthetics.
ETA: This guy would come off as much less "fan boy" and a lot more "engineer" if he had chosen a much more realistic ship such as the Discovery from 2001.
Of course it is, that's my point! Like I said, if you have only one rotating section, the gyroscope effect (i.e. conservation of angular momentum) will tend to keep the rotational axis aligned, which will make it difficult to turn the craft (except around that axis). Having two counterrotating sections will average out the angular momentum to zero, so there's no gyroscope effect and the craft or habitat can easily be realigned in any direction. That's true of any spacecraft or habitat with a rotating section, because it's a universal law of physics. If you look at proposals for space habitats such as Gerard K. O'Neill's in The High Frontier, you'll see that the plans for his O'Neill cylinder or "Island Three" habitats include counterrotating pairs, because cancelling out the gyroscope effect is essential for keeping the solar mirrors/windows aligned as the habitat orbits the Sun.
Constants long duration acceleration seems to be a better way than rotation.
Well, in the Apollo craft the Velcro was only places where astronauts would need to "stand" in order to operate the craft.
Not to mention, could you imagine the noise of a couple astronauts with Velcro shoes walking around a Velcro floor? How long could you listen to that without going ape shit?
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Sorry, no, it's not necessary. Useful? yes. Helpful? yes. but necessary? no. Yes, it would be harder to maneuver a ship with only the one rotational direction due to gyroscopic effects, but not impossible or even very difficult. For maneuvers you can just stop the rotation, then start it up again after maneuvers are complete. Much easier than trying to get counter rotating sections working together what with load balancing issues and everything else that comes with it. There have been many designs using only one rotational section over the years including the most recent Nautilus X by NASA. I agree that at a certain point the benefits of a counter rotating section outweigh the engineering problems, but today, using our technology, it's probably best to K.I.S.S.
^But none of that has anything to do with whether the ship is shaped like the Enterprise. The point is that the advantages and drawbacks of a rotating habitat section are the same regardless of how the vessel is shaped.
You're just not getting my point. We're talking past each other. Forget it.
TerraNovan
Lieutenant Commander
This is an issue of semantics, in orbit the iss, is considered a zero(micro) gravity environment, The reality is, the difference in gravitational forces 100km up isn't that extreme and it's the same outward acceleration keeping us in orbit, the weightlessness, isn't considered artificial and is taken for granted, why is it such a conceptual stretch, to say the same for gravity wheels. I agree technically, but as long as were considered being in orbit a microG environment, I think we should back away from the "artificial" tag. Again my point was that this shouldn't be hard to imagine from any high school graduate.
^Well, of course the "gravity" produced by rotation should be called artificial gravity, for two reasons. One, it's not actual gravity, i.e. the fundamental interaction that attracts masses; instead, it's weight created by a different form of acceleration, and calling it "gravity" is just a figure of speech. (Although one could argue that "gravity" literally means heaviness, so it's accurate in that sense.) Two, the word "artificial" doesn't actually mean "unreal;" it literally means "made by art," i.e. created through the application of human skill and effort. The weight generated by the rotation of a space habitat is the result of human invention, therefore it is artificial by definition.
By the way--I love Forgotten History, Christopher--esp. your explanation of Spock beaming the earlier versions of the 20th Century folk back into themselves. I had the idea of a detached timeline, where due to the peculiar nature of the warp that the earlier Enterprise was no longer in the sky--that history was dragged away by Enterprises return (partially) to its own time.
TerraNovan
Lieutenant Commander
Yes but they don't call it artificial tea, artificial sleep when one sleeps on a bed, or artificial music. I guess the real problem is those that say we suffe from living in a zero g environment, they should say that the rotational forces of orbit cancel out the gravitational forces, so the real problem is those pesky rotational forces of being in orbit.
If that is the case than our problem, isn't gravity itself but rotational forces, it would seem using rotational forces is the only logical answer.
That's because those things aren't human-made by contrast with a more common natural equivalent. That's the context in which the word "artificial" is normally used -- such as artificial sweetener as opposed to sugar or honey, artificial fibers as opposed to cotton or wool, etc.
"Artificial gravity" is the legitimate and correct term for what we're discussing. Translated literally from the Latin, it means "heaviness created by human effort," and that is a completely accurate description of the phenomenon.
No, you've completely misunderstood what I was saying. A planet orbiting the Sun is a very different situation from a rotating artificial habitat. A planet around the Sun is pulled inward by its gravity so it needs the outward centrifugal force to cancel that and stay in orbit. But a person inside a space habitat is not pulled toward its center because there's no mass great enough to generate a significant gravitational force, so they'll float in free fall unless the habitat rotates and generates a centrifugal force which pulls them outward, which is then their source of weight. The former is two equal and opposite forces cancelling each other; the latter is a single force acting outward. I was attempting to show you how the same phenomenon of centrifugal acceleration applied in two different contexts. Somehow you misunderstood and thought I was saying they were identical situations.
If that is the case than our problem, isn't gravity itself but rotational forces, it would seem using rotational forces is the only logical answer.
Yes, that's what I've been saying all along.
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