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So a lot of movies, TV shows, illustrations, etc., show spacecraft
generating "gravity" via rotating hull sections. In many cases, this rotating section spins around a stationary central hull. The question I have for those more knowledgeable in this area than I is: What is the connection between these two sections? Obviously there shouldn't be a physical connection between the two hull sections (right?). But would this mean space enough between the spinnning hull and the stationary hull for the interior atmosphere to escape? Or is it sealed somehow? Sorry if this is a beginner's or nitpicker's question; it's just something that I've been wondering about for a while. Thanks in advance to everyone who'll help me expand my knowledge here. --James |
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On 15/02/2011 10:35 PM, James W wrote:
So a lot of movies, TV shows, illustrations, etc., show spacecraft generating "gravity" via rotating hull sections. In many cases, this rotating section spins around a stationary central hull. The question I have for those more knowledgeable in this area than I is: What is the connection between these two sections? Obviously there shouldn't be a physical connection between the two hull sections (right?). But would this mean space enough between the spinnning hull and the stationary hull for the interior atmosphere to escape? Or is it sealed somehow? Sorry if this is a beginner's or nitpicker's question; it's just something that I've been wondering about for a while. Thanks in advance to everyone who'll help me expand my knowledge here. --James In 2001 A Space Odyssey, it was clear that the entire rotating assembly was inside the non-rotating pressure hull, so that the issue of air leakage didn't arise. In Mission to Mars, that was not the case, and it would have required some kind of sliding hermetic seal which is probably not feasible. In practice, the most obvious solution seems to be to rotate the entire spacecraft, but doing that removes many of the cinematically interesting scenes. Sylvia. |
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James W wrote:
So a lot of movies, TV shows, illustrations, etc., show spacecraft generating "gravity" via rotating hull sections. In many cases, this rotating section spins around a stationary central hull. The question I have for those more knowledgeable in this area than I is: What is the connection between these two sections? Obviously there shouldn't be a physical connection between the two hull sections (right?). But would this mean space enough between the spinnning hull and the stationary hull for the interior atmosphere to escape? Or is it sealed somehow? If you have separate rotating and non-rotating sections (as in, for example, the movie "2010"), then yes, you need a rotating air-seal between them. This takes a bit of effort for the engineers, but is certainly possible. -- -- "Jonathan Thornburg [remove -animal to reply]" Dept of Astronomy, Indiana University, Bloomington, Indiana, USA "Washing one's hands of the conflict between the powerful and the powerless means to side with the powerful, not to be neutral." -- quote by Freire / poster by Oxfam |
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On 18/02/2011 1:30 AM, Jonathan Thornburg [remove -animal to reply] wrote:
James wrote: So a lot of movies, TV shows, illustrations, etc., show spacecraft generating "gravity" via rotating hull sections. In many cases, this rotating section spins around a stationary central hull. The question I have for those more knowledgeable in this area than I is: What is the connection between these two sections? Obviously there shouldn't be a physical connection between the two hull sections (right?). But would this mean space enough between the spinnning hull and the stationary hull for the interior atmosphere to escape? Or is it sealed somehow? If you have separate rotating and non-rotating sections (as in, for example, the movie "2010"), then yes, you need a rotating air-seal between them. This takes a bit of effort for the engineers, but is certainly possible. Do you have any references describing how it could be achieved? I've looked, and I cannot find anything. Sylvia. |
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I wrote
| If you have separate rotating and non-rotating sections (as in, for | example, the movie "2010"), then yes, you need a rotating air-seal | between them. This takes a bit of effort for the engineers, but is | certainly possible. Sylvia Else wrote: Do you have any references describing how it could be achieved? I've looked, and I cannot find anything. I was originally quoting Henry Spencer in this newsgroup (article , dated 30 June 2003), when he wrote : Making an essentially zero-leakage rotating joint is not a big problem, : especially for slow rotation. I don't have any specific references, but google "rotating shaft seal" brought up about 285,000 hits just now, many of which looks relevant. For example, each of http://en.wikipedia.org/wiki/Rotatin...echanical_seal http://www.azom.com/Details.asp?ArticleID=504 http://www.mt-online.com/component/c...l?directory=90 http://www.freepatentsonline.com/3088744.html has some useful general information. This is quite standard industrial technology. For example, every ship has a rotating seal where its propellor shaft(s) exits the hull. Loaded oil tankers may have their propellor shafts more than 10 meters (33 feet) below the water level, giving an ambient water pressure of greater than 1 atmosphere. Indeed, submarine propellor-shaft seals must withstand up to ~50 atmospheres of pressure (= water pressure at a depth of ~1500 ft). ciao, -- -- "Jonathan Thornburg [remove -animal to reply]" Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA "Washing one's hands of the conflict between the powerful and the powerless means to side with the powerful, not to be neutral." -- quote by Freire / poster by Oxfam |
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On Feb 18, 9:03 pm, Sylvia Else wrote:
Do you have any references describing how it could be achieved? I've looked, and I cannot find anything. Fluidic seals of various sorts are one possibility. See, for example, http://en.wikipedia.org/wiki/Ferrofluidic_seal |
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On Thu, 17 Feb 2011 09:30:09 EST, "Jonathan Thornburg [remove -animal
to reply]" wrote: If you have separate rotating and non-rotating sections (as in, for example, the movie "2010"), then yes, you need a rotating air-seal between them. This takes a bit of effort for the engineers, but is certainly possible. A bigger problem than the pressure seal would be the need to transfer control signals and power through the moving section. Although... given the advancements in wireless technology, that isn't as big a problem now as it used to be. |
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At Sun, 20 Feb 2011 11:46:32 EST Len Lekx wrote:
On Thu, 17 Feb 2011 09:30:09 EST, "Jonathan Thornburg [remove -animal to reply]" wrote: If you have separate rotating and non-rotating sections (as in, for example, the movie "2010"), then yes, you need a rotating air-seal between them. This takes a bit of effort for the engineers, but is certainly possible. A bigger problem than the pressure seal would be the need to transfer control signals and power through the moving section. Transfering *power* to some sort of moving object is *really old tech.* -- every rotating electrical device (motors, generators, alternators) and *electric* subway and commuter trains, and trolly cars need to do this all the time. Slip rings would work. Presumably, we are not talking about a solid shaft (like a propeler), but a rotating tube. Using something not unlike a circular trolly wire with a trolly wheel or shoe would work. So would a contact shoe against a ring plate. Although... given the advancements in wireless technology, that isn't as big a problem now as it used to be. Right. Control signals could just be encoded as wireless ethernet packets. And anything critical could be handled by additional slip rings, much as the power. Plumbing would be interesting, but also doable -- just a different sort of concentric rotating seals at the center of rotation. -- Robert Heller -- 978-544-6933 / Deepwoods Software -- http://www.deepsoft.com/ () ascii ribbon campaign -- against html e-mail /\ www.asciiribbon.org -- against proprietary attachments |
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![]() In article , lid says... On 18/02/2011 1:30 AM, Jonathan Thornburg [remove -animal to reply] wrote: James wrote: So a lot of movies, TV shows, illustrations, etc., show spacecraft generating "gravity" via rotating hull sections. In many cases, this rotating section spins around a stationary central hull. The question I have for those more knowledgeable in this area than I is: What is the connection between these two sections? Obviously there shouldn't be a physical connection between the two hull sections (right?). But would this mean space enough between the spinnning hull and the stationary hull for the interior atmosphere to escape? Or is it sealed somehow? If you have separate rotating and non-rotating sections (as in, for example, the movie "2010"), then yes, you need a rotating air-seal between them. This takes a bit of effort for the engineers, but is certainly possible. Do you have any references describing how it could be achieved? I've looked, and I cannot find anything. Nautilus-X (see the link to the Powerpoint in the article below) http://www.spaceref.com/news/viewsr.html?pid=36068 Jeff -- " Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/2011 |
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