phoebos@w... wrote:
>simpler systems last longer and are less prone to malfunctions. Two
rotating cylinders are an interesting idea, but it seems to me to
involve a lot of mechanics and the potential for failure.
> let us see who can come up with the simplest and most effective idea
and extrapolate from that.
> How simple can we get it, folks?

How about this: (From an earlier post)
* A sphere has the least surface area for a given enclosed volume
(This means the least shielding mass), but small level surface area at
the desired G.
* A torus is maximally stable, but little area also, and least volume.
* The cylinders are unstable, but the best flat internal surface area.
Ecnclose a sphere with shielding (the most massive part), and build
up the equatorial area with floors & chambers under the inner open
volume. This gives the least shielding mass for the enclosed volume,
the best flat inner surface area for habitation, and the massive
spinning rim (center of mass) of the stable torus.

I also have always liked the "hatbox" design from "the High
Frontier". A simple drum shape, with tiny transparency at the center
for admitting light & blocking radiation. The design in the book used
a non-rotating shield with the "crystal palace" inside, but I'd like
to investigate just using a rotating concrete/sintercrete drum.
Possibly with several decks under the central open volume, we could
dispense with the 2 meter shield, by letting the underdecks of
structure & housekeeping equipment serve as shielding mass.
The exterior agronomy area could possibly be dispensed with, if we
use the tiered farming scheme which Heppenheimer described for the
Stanford torus (Algae ponds at the top, draining into the fish &
mussel ponds, draining successively down into more & more complex
life).

Alternatively, I'd like to hear some discussion of the orbital
greenhouse design of Andrew Nowicki
http://www.islandone.org/LEOBiblio/SPBI1GH.HTM
Note that they are small sized (1 family), but parts of his design
philosophy could be used. A small design is also conducive to the idea
of a pioneering family going off into the wilds with an ax & an ox to
build a home.

I particularly like his windows. I never understood the need in
"Island 3" for equal land & window areas (I hate the huge flappy
mirrors). Why not something more like the light strips in Clarke's
"Rama"; Exterior mirrors admit light through openings which are much
smaller than the land area they illuminate. The light can be
concentrated as much as possible coming through the windows.

(Does anybody know off-hand the intensity of sunlight in space?
Optimally, it's ~1360 watts/m^2 at Earth surface, I believe, but
what's the factor for how much the atmosphere blocks/scatters?)

Mirrors can be as big as needed, and light pipes could be as small as
possible. Taking the light pipe concept to the extreme, light could be
taken from a light conduit at different depths into the hull, and
ducted to wherever needed, in the amounts & frequencies desired. Note
that the light could come in from anywhere on the exterior, and
illuminate a compartment from anywhere.
Any particular compartment could go dark at any time desired, simply
by shutting its conduit.

From: "John Frazer"
To:
Sent: Thursday, March 15, 2001 10:23 PM
Subject: [spacesettlers] Back to basic designs

[snikt]
> (Does anybody know off-hand the intensity of sunlight in space?
> Optimally, it's ~1360 watts/m^2 at Earth surface, I believe, but
> what's the factor for how much the atmosphere blocks/scatters?)
[snikt]

According to Savage's book, this 1360 W/m^2 value is for sunlight *in
space*. Due to atmospheric blocking/reflection/scattering, however, the
amount of energy that hit the Earth surface is just 40% of the original
value. (Note: when I say "sunlight" I'm in fact saying "energy irradiated by
the sun in the form of electromagnetic waves". The atmosphere blocks a lot
of the wavelengths, like infrared and ultraviolet, but let a great deal of
visible light to pass through.)

Lucio