Futuof Space Colonization

From: "Ryan Healey"
To:
Sent: Wednesday, May 29, 2002 9:14 AM
Subject: Re: [spacesettlers] Future of Space Colonization
(...)

> Personally I prefer the stanford torus due to the larger rotational
radius.
> For the first one it'll either be stanford torus or Bernal sphere. That
will
> be decided upon by whoever has to pay for it. Later on we'll just let the
> colonists select the designs that are best for them.
(...)

Personally, I think that the first rotating space habitat will be neither a
Stanford Torus nor a Bernal Sphere. I think that it will be a dumbbell
habitat - you can have relatively small spheres supporting a relatively
large population dispersed along the whole spherical volumes, and a
rotational radius basically as large as you want. A zero-g solar power
facility in the outside, with a touchless connection to the central-hub
through a voltage transformer that transfers energy without contact, or
through microwave beaming. Artificial lighting (using LED panels or
whatever) in agricultural volumes inside. Heat radiators along the cable
connecting the spheres.

This design is highly compact and can support an arbitrarily small
population regardless of rotational radius. Since the first habitats will
probably be built with much of its pieces coming from Earth, I think that an
economical design like the dumbbell would be favored instead of colonies
that occupy the whole circumference covered by the rotation, like spheres,
tori and cylinders.

Well, but maybe we are talking about different things. I think that in,
"The High Frontier", O'Neil traces a line between earlier settlements (and I
think that the dumbbell above would settle in that classification) and
advanced settlements (like Islands from One on), and he concentrates on the
second category.

However... With the development of new materials, e.g., carbon nanotubes,
one could make *really* long dumbbell habitats. Imagine for instance a
dumbbell 200 Km long with a sphere 4 Km in diameter on each end. Even
supposing a lot of volume for each person (say, 1000 cubic meters per
capita), each sphere could hold more than 30 million people. Supposing that
atmospheric pressure inside the spheres decreases with "height" as it does
on Earth (actually, it decreases at a slower rate, but I CAN'T find the damn
formula!!!), there could be people living even below the "Upper Pole" of
each sphere, and so this huge population could be dispersed along the whole
volume in a kind of layered city or whatever. Since the rotational radius
would be huge, each layer of the city would be essentially parallel to the
other, with no noticeable curvature. From the point of view of the people
inside the city, they would be in a domed city, and not inside a space
colony where the sky is really the other side of the ground... Finally,
agricultural tori without shielding could be distributed along the length of
the tether.

Lucio Coelho