How to build this?

>For all you engineers. If we want a spaceship with a rotating torus
>section how do we mate it with a non-rotating spindle?
>
>WHat would the structural problems be? How would you insure pressure
>worthiness?
>
>Obviously, the rotating section can be encased within a pressure
>vessel, like Discovery from 2001:A Space Odyssy. Is this optimum?
>
>Any thoughts?
>
>TangoMan

It seems for a vehicle traveling in various states of acceleration, a
design that incorporates a hard rotating arm/spoke with a pendulum like
section hanging off the end (allowing fore and aft motion) would accomodate
the crew/passengers better. Unfortunately, such a design doesn't lend
itself well to encapsulation in an exterior pressure hull due to waste of
volume. Additionally, it won't have a full gravity environment due to the
economics and mechanics of such a configuration, nor does it lend itself
well to having a counter-rotating section. That said, it is arguably the
most elegant solution for a ship that has variable acceleration profiles
due to journey choices and cargo manifests. One arguably bizzare variation
is to have the rotating arms on fore/aft hinges at the hub, and a variable
circumference torus (sweeping out a cone shape while under ship
acceleration, and a wheel shape when the ship is not accelerating)

Other choices being a rotating torus with only a transfer cab system up and
down its radius to a non-rotating hub, or a non-rotating torus pressure
hull with a contained rotating section with a contained transfer cab in the
torus for transitioning to zero-g (with either a pressurized arm/spoke or a
zero-g transfer cab to the hub).

Fundamentally it is a tradeoff between the convienance of a rotating seal
for continuous use with the associated maintenance headaches and the great
forces and stresses involved at the hub, versus a transfer cab system with
a heavily used airlock seal and the maintenance associated with what
amounts to a separate spacecraft.

The full sphere pressure hull method isn't terrible, since you could have
counter-rotating hemispheres or any lesser shape, but to get to full
gravity would require an inordinately large pressurized volume. Having a
"hollow center" fiilled with non-rotating spaces for crew and cargo would
deal with the inconvienant low gravity sections. To justify such a large
pressurized volume however would mean the transport of large quantities of
manufactured goods, as most bulk goods could be carried externally in
tanks, and the remaining other types of cargo that can survive vacuum would
also be externally carried. Such a vehicle is only good for doing "tramp
steamer" cargo services to isolated and non-self sufficient ports of call
and delivery of initial machinery to soon-to-be self supporting facilities.
Additionally, it does not lend itself well to higher acceleration profiles
for the ship as the decks can not rotate to accomodate the changes in
acceleration vector, thus dooming the ship to long flight durations. Thus
such a ship would be in essence required to be a very large cargo carrier
of the "slow boat" variety, unless it is intended to be a mobile
construction shack in which case it carries all the materials for
constructing new facilities, then moves on to the next jobsite after
picking up new construction materials.

Asteroza