Question about Centrifugal Gravity
James W
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
Sylvia Else
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.
Jeff Findley
In article <93da4e6e-38dd-40de-93b9-1b11ddbfe026
@s11g2000yqc.googlegroups.com>, ward....@gmail.com says...
>
>
> it sealed somehow?
>
>
> here.
>
> --James
Example here:
Nautilus-X - NASA's Multi-mission Space Exploration Vehicle Concept
http://www.onorbit.com/node/2970
In the above article is a link to the "full document" (Powerpoint).
Jeff
--
" Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry
Spencer 1/28/2011
Jonathan Thornburg [remove -animal to reply]
> 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]" <jth...@astro.indiana-zebra.edu>
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
Sylvia Else
> James W<ward....@gmail.com> 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.
Allen Thomson
> 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
Len Lekx
to reply]" <jth...@astro.indiana-zebra.edu> 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.
Robert Heller
>
> On Thu, 17 Feb 2011 09:30:09 EST, "Jonathan Thornburg [remove -animal
> to reply]" <jth...@astro.indiana-zebra.edu> 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 / hel...@deepsoft.com
Deepwoods Software -- http://www.deepsoft.com/
() ascii ribbon campaign -- against html e-mail
/\ www.asciiribbon.org -- against proprietary attachments
Jeff Findley
In article <8s5v3n...@mid.individual.net>, syl...@not.here.invalid
says...
>
> > James W<ward....@gmail.com> wrote:
> >>
> >> it sealed somehow?
> >
> > certainly possible.
> >
>
Nautilus-X (see the link to the Powerpoint in the article below)
http://www.spaceref.com/news/viewsr.html?pid=36068
Peter Fairbrother
It can be done at simplest with the kind of rubber seal used in car
engines to keep the oil in, or with various other rotating seals of
greater complexity - but it doesn't usually need to be done.
For instance in a long flight, eg to Mars, you spin up the living
capsule say at one end of a tether and the landing module or whatever at
the other end, and it just stays spinning until a day or two before you
arrive.
For a space station with two sections the airlock between them (you do
want an airlock there!) either mates with the spinning section or with
the stationary section.
When moving from the rotating section the airlock opens to the RS,
people transfer into the airlock, it closes, it unmates with the RS, it
despins, then it mates with the stationary section etc.
In some scenarios the sections should not be in contact, if possible -
the main reason for having two sections is that you want microgravity in
one section and earthlike gravity in the other.
In order to have good microgravity with eg a rotating seal the center of
gravity of the rotating section must be at the center of the seal - but
this causes problems as eg people move around the rotating section. This
also puts pressure on the seal. It may be best to have no actual contact
between the sections, just a transfer airlock.
-- Peter Fairbrother
Joe Pfeiffer
lot more pressure has to be handled than the mere 15psi of sea level
atmospheric pressure -- auto engines, ship propellers... I don't know
of any on the scale of a rotating space ship hull section, but I
wouldn't be at all surprised to learn it's been done. Likewise, getting
electricity through a rotating interface is also well established:
tanks (as in armored vehicles, not as in something to store liquids!)
use metal rings and brushes.
Tony M
relatively rotating sections of a spacecraft and have power, data and
plumbing run across. From a practical perspective this would be a
complex, expensive, heavy and fault susceptible assembly, hard to
justify as a feature.
The important question is why would there be a need for relatively
rotating sections? I, personally, cannot think of a good reason. I am
with Sylvia on this one; the entire ship would have to rotate as a
single hull. If there is a need for a non-rotating section (maybe a
science lab) it should be internal to the main hull, not a separate
hull section.
Jonathan Thornburg [remove -animal to reply]
> The important question is why would there be a need for relatively
> rotating sections? I, personally, cannot think of a good reason. I am
> with Sylvia on this one; the entire ship would have to rotate as a
> single hull.
(a.k.a. "despun") section:
* antennas to communicate with the Earth
* telescopes to observe the target planet
* docking adapters for any sub-spacecraft
* airlocks for any spacewalks
* possibly heat radiators that want to avoid direct sunlight
* Whipple shields against orbital debris (if you're in a high-debris
orbit, i.e., a low-to-moderate-altitude Earth orbit)
--
-- "Jonathan Thornburg [remove -animal to reply]" <jth...@astro.indiana-zebra.edu>
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA