How to build this?

I like this idea. Perhaps a teardrop shaped, multilevel container at each
end, insted of arc segments... Just another idea. Perhaps, in order to
minimize surface area, the containers could be spherical. If I follow
Claudio's idea, the radial arms could be long enough that the 'gravity
difference between each level in the containers would be unnoticable.

Val

>Date: Sun, 04 Apr 2004 14:00:46 -0000
>
>posted this a couple of days ago but doesn't seem to get there, so I
>think I'll repost it, apologies if you get it twice...
>
>I'm no engineer but I always thought the rotating torus design is
>fundamentally flawed... ;)
>The problem is not the "rotating" bit, is the torus. Why a whole torus?
>The main issue I see is that in this design the entire circumference
>that rotates is pressurised, and then the entire contraption needs to
>spin very fast indeed to get any simulated gravity at all, being
>necessarily of a small radius, while all you really want are the two
>points, the center and the rotating end one, and the further apart
>they are the better it is. What need there is to have a continuous
>closed circumference? Why not just spin a very short section at the
>end of a much longer radial arm, eventually with a second one as a
>counterbalance at the other end, if needed?
>Basically take your "wheel" design and multiply the radius by say a
>factor of four or more, then saw off all but two very small sections
>at the opposite ends of the wheel. What you are left with is a system
>that spins much faster at the circumference end (where you want to
>have the artificial gravity) but much slower at the hub, where you
>have the bearings.
>The rotating parts needs not be pressurized at all, making the
>construction and maintenance that much simpler, as all you need is a
>pressurized cab moving between the pressurized section at the hub and
>the pressurized section at the far end(s) of the arm. The "arm" (or
>arms) itself doesn't need to be pressurized and in fact it doesn't
>need to be anything more than a cables or ribbons system, hold in
>tension by the spinning itself. To make a concept example, rather than
>a bicycle wheel you can have a "bolas" design.
>Because you concentrate all the pressurized volume in two points only
>instead of distributing along the entire circumference you can have a
>much larger radius (easily ten times larger) for the same mass/cost.
>Seems much more efficient? Maybe there is some technical reason why
>this is not possible but then please explain it to me! :)
>
>Cheers,
>
>Claudio
>
>--- In ssi_list@... "victoriatangoman"
> > > The picture therefore seems to be showing a vehicle therefore
> > > rather than a space colony.
> >
> > Sorry for the confusion, yes, I'm referring to spaceship design.
> >
> > > The best vehicle design would of course be the one with the least
> > > surface area that would require radiation shielding and therefore
> > > the least mass and least energy required per change in velocity.
> >
> > Which would be a sphere, correct?
> >
> > What I liked about this ship from the movie RED PLANET, was the
> > counter-rotating rings. Each would counter the angular momentum of
> > the other. Is this correct?
> >
> > If there was only one ring, how would the angular momentum be
> > accomodated?
> >
> > Here are some quick calculations:
> >
> > If we want a 1.0 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 86 m
> > With 5 rotations per minute the radius of the ring = 97 m
> > With 4 rotations per minute the radius of the ring = 117 m
> > With 3 rotations per minute the radius of the ring = 160 m
> >
> > If we want a 0.75 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 80 m
> > With 5 rotations per minute the radius of the ring = 88 m
> > With 4 rotations per minute the radius of the ring = 103 m
> > With 3 rotations per minute the radius of the ring = 136 m
> >
> > If we want a 0.66 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 77 m
> > With 5 rotations per minute the radius of the ring = 85 m
> > With 4 rotations per minute the radius of the ring = 98 m
> > With 3 rotations per minute the radius of the ring = 127 m
> >
> > If we want a 0.5 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 73 m
> > With 5 rotations per minute the radius of the ring = 79 m
> > With 4 rotations per minute the radius of the ring = 89 m
> > With 3 rotations per minute the radius of the ring = 111 m
> >
> > If we want a 0.33 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 69 m
> > With 5 rotations per minute the radius of the ring = 73 m
> > With 4 rotations per minute the radius of the ring = 79 m
> > With 3 rotations per minute the radius of the ring = 94 m
> >
> > If we want a 0.25 gravity environment:
> >
> > With 6 rotations per minute the radius of the ring = 67 m
> > With 5 rotations per minute the radius of the ring = 70 m
> > With 4 rotations per minute the radius of the ring = 75 m
> > With 3 rotations per minute the radius of the ring = 86 m
> >
> > OK, is it a good idea to have counter-rotating rings? I'm assuming
> > it is.
> >
> > If that is what is desired, then I fall back to the design of the
> > Discovery in 2001:A Space Odyssey. Put the centerfuges inside the
> > shell of the sphere. This eliminates the pressure seal issue for the
> > outer shell becomes the unitary pressure vessel.
> >
> > Place the two counter rotating centerfuges next to each other at the
> > center of the spherical shell. All of the volume outside the two
> > narrow centerfuges becomes zero-gravity crew quarters and storage.
> >
> > If you look at the numbers above you'll see that if the crew can
> > survive sustained exposure to 6 rpm then the radius difference
> > between the different gravity simulation levels drops in smaller
> > increments than at lower rpms.
> >
> > I know from the Stanford Torus study that they recommended a
> > rotation rate of less than 3 rpm so that a broad range of people
> > could accomodate themselves to living within the Habitat.
> >
> > However, a spaceship doesn't have to have those design constraints,
> > and we could select a crew that can adjust to a higher rpm rate.
> > Does anyone have any information on how high rpm rates can go and
> > how long they can be sustained so that the crew can live normally.
> >
> > Lastly, consider the volume of the sphere that could be used for
> > other purposes. If it is too much space, then perhaps we could
> > design a disk shaped ship within which to place the centerfuges but
> > now we're faced with the prospect of flat surfaces and corner joints
> > within the pressure vessel design. How problematic are they?
> >
> > Any thoughts?
> >
> > TangoMan
>

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