Cities in space - Singles or clusters?

Robert,

Sorry, I think that I may have the wrong idea of what you meant or you have
misunderstood what I meant. I assumed that you were talking about a ring of
cylinders with each cylinder spinning on its own axis to provide its
gravity, this would mean that each hab could have a different gravity, the
other option is that the habs were locked into the ring and it was spinning
around the Earth to provide the same gravity to each habitat, this would
need a very, very strong material to do this.

Okay, back to basics, the ring you describe (assuming I have it right) is
what I refer to as a 1D structure, put simply it is like two railroad tracks
with habitats in place of sleepers, its just like a single line, 1
dimensional. Curve the tracks around to form a circle and you have your
ring. My problem is that to travel from any hab to one on the far side of
the circle is going to take a certain amount of time.

Take the same a number of habs in the railroad tracks and cut it into equal
bits, if you had 100 habs, you would cut it into 10 parts each with 10 habs,
arrange them into a square and now you have a 2D structure, to get from hab
1 to hab 50, you do not need to pass 50 habs, just 5 to the side and 5 up,
total 10, saving 40.

Now you move into a 3D grid (my cube) and the trip time drops down even
further. The cube I was referring to is just a framework holding a large
number of habitats, they would spin on their own axis (equal number one way
and the other way, zero total spin) inside the frame, this gives them
whatever gravity was needed in each habitat.

The reason for putting a number of habitats in a framework, be it a cube or
some other shape, is to provide the basis of a transport system, a way of
providing shielding and keeping a group of habitats with some kind of common
ground, be it a nation or some sort trade block or something else that
motivated them to want to stay together.

My difficulty with your ring around the world, while a great feat of
engineering is why do it? If you wanted to keep a number of habitats in a
group, then wouldnt a more compact shape be better or is there some other
reason from this configuration, is there some advantage that I am missing?

Darren

From: Robert
Reply-To:
Date: Wed, 30 Aug 2006 05:38:45 -0000
To:
Subject: [spacesettlers] Re: Cities in space - Singles or clusters?

please explain why a cube would have the proper gravity. the only
known way to create the effect of gravity is with centrifical spin.
this means you need a cylender or a ring. some for of a circle.

the ring around the planet would be made up of many cylinders with
equipment between to constantly adjust the distance bewteen them.
there would be no need for reaction mass, as the all the moment would
be done with either hydrolic or electromagnetic forces powered by
solar cells.

as for how long it would take to get to the opposite side of the
ring, first it would depend on how big the ring is, and how fast you
are traveling. the ring itself would not give any sense of gravity.
how long does it take now to travel from one side of the globe to the
other.

--- In spacesettlers@yahoogroups.com
, Darren wrote:
>
> Robert,
>
> I will concede to anybody who has the maths to prove the case that
the ring
> would be stable but it isnt just the effect of the moon pulling on
the
> ring, that is a concern, although I do think that will be a major
problem.
> My main concern is the orbit of the ring itself.
>
> Consider, can you name anything that is in a true circular orbit?
Sure you
> could put an object into a circular orbit but how long will it stay
that
> way, small lumps and bumps in the Earths gravity field is going to
slowly
> change this, you could constantly correct the orbit to keep it in a
perfect
> circle, by using a lot of reaction mass or better yet by some kind
of
> electro-dynamic tether to make your corrections, no need for
reaction mass.
> You then build your globe encircling ring and you will have to keep
> correcting this because if you dont you will soon have forces
trying to
> pull your ring apart.
>
> But putting all that aside, suppose you have your ring and its
stable in
> orbit, the ED tethers are working to keep it in a circle, your
framework is
> strong enough to be used as a transport system, I come back to my
question,
> why?
> The ring is certainly an impressive achievement, it would be
considered an
> engineering masterpiece but in terms of travel time from one side
to the
> other, in terms of the use of space, it seems to me to be a bit a
waste. You
> are building the orbital equivalent of urban sprawl, a cube with
the same
> number of habitats could be used much smaller, travel time and use
of
> resources could be more efficiently used.
>
> I think that your ring around the world would be an incredible
sight but I