A simple question about Island 3

>> windows design for Island 3 is that half the area is

Remember that Island 3 was one of the very first 'space colony' concepts.
The goal was to make a large, Earth like area - ie, uniform
Earth-normal gravity,
day-night, they even arranged for the sun to rise and set (well, it rose in
the north, and set in the north, but that is a minor detail.)

Later designs tried other arrangements for where the light enters. Notably:

Stanford Torus:
has the sunlight coming through the ceiling, (and through chevron
mirrors, for radiation shielding)
thus no useful 'ground-space' is wasted by windows.

http://ssi.org/assets/images/Stanford_Torus.jpg
>>> The Stanford Torus - This space habitat design resulted from a NASA-Ames/Stanford University summer study. It's a wheel 1.1 miles in diameter.

Here is a good image of the ceiling windows under construction
http://www.marshome.org/images2/displayimage.php?pos=-1848
[ If anyone has a good reference or knows the source of this image,
let me know, and I will update
the caption & artist credits. ]
You can see 4 versions by searching for "Stanford Torus"
at http://www.marshome.org/images2/search.php
- - - -

Bernal Sphere / Island One:

http://ssi.org/assets/images/slide17-large.jpg
The glowing ring in this image are the windows, they are high up on the 'hill',
above the penthouse apartments, where ground would be too steep to
walk or have plants.
Thus the wall space they take up is not the most useful.
>> Interior of Island One - The circumference is nearly one mile. Houses and apartments are shown oriented to sunshine. Agriculture and industries are reached through zero-gravity corridor at top.
- - - -

Agricultural areas of Bernal Sphere:

A different design, which also has sunlight coming through the
ceiling, leaving maximum ground area
for growing crops.
Image is near bottom of " http://ssi.org/?page_id " where it says
>>Agricultural Area - Banded toruses comprise the agricultural area of a space colony. Based upon work by Don Davis.
[incidentally, there are bad web links on that page, to
http://ssi.org/assets/images/slide18.jpg
[ and to http://ssi.org/assets/images/slide18-large.jpg which seems
to have been deleted ]

There is a better overview shown in
http://www.marshome.org/images2/displayimage.php?pos=-1836
[ Again - If anyone has a good reference or knows the source of this
image, let me know, and I will update
the caption & artist credits. ]
- - - - -

I had worked on a space settlement design, which had multiple interior
rotating cylinders,
separate radiation shield, and rotating tethers for non-rocket
transportation. One of the major
problems I had was how to get sunlight in. If anyone wants to help me
model my design in
cad, let me know.

I am quoting Mike's earlier message, because it gives a good summary
of some of the designs. Below.

-Bruce Mackenzie

>
>> One of the things I don't like about the mirrors and
>> windows design for Island 3 is that half the area is
>> window. You can't live on it, you can't play on it,
>> you can't do anything but clean it (and oh are you
>> ever going to have to do a lot of that!).
>>
>> At different times I've advocated bringing in light
>> via fiber optics or using LED panels printed by a
>> variant of the ink-jet printer.
>
> I think a far more economical solution is slight concentration of sunlight
> via concave primary mirrors. You'll notice that in the Island One or Bernal
> Sphere design, the windows make up a good deal less than half of the
> internal surface area:
>
> http://ssi.org/assets/images/Ch08p125.gif
>
> The Sunflower design doesn't use concave mirrors but has smaller windows as
> a consequence of the fact that each window is letting in twice the sunlight
> from two different angles:
>
> http://ssi.org/assets/images/Ch06p094.gif
>
> This design has a single, very small, window:
>
> http://ssi.org/assets/images/Ch06p086.gif
>
> The Hatbox design also uses concentration to achieve very small window area:
>
> http://ssi.org/assets/images/Ch99p287.gif
>
> Of course there are limits to how much concentrated sunlight you can focus
> through a window. You can't allow temperatures that soften the glass. But
> enormous improvements in reducing the window area are possible well short of
> approaching that point.
>
> Regards,
>
> Mike Combs

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