Mirrors versus diffuse reflection

How about efficient solar->electric conversion and efficient LED based
artificial lighting? If you can nearly match optical energy efficiency
artificial lighting makes everything *a lot* easier.

John Frazer wrote:
>
> Dr. Omni wrote:
> > I have been thinking about designs for spherical and cylindrical
> rotating habitats following what I call "Frazer's
> Guidelines" ...because John Frazer was the first one that I saw
> mentioning them, in the Space Settlers list...
>
> First on this list, maybe. I cribbed most of it from Andrew
> Nowicki's "greenhouse" model habitat, and A.C. Clarke's "Rama"
> spacecraft. I did roughly develop most of the rest of it (with some
> help from members of the LUF email lists): the "light ducts"
> admitting light through the floor of the hab to the opposite side of
> the interior, glass block mirrors/deflectors/difusers, etc.
> Note that such "light ducts" may also work through very great
> thicknesses of floor space, such as under-levels of decks for
> machinery or habitation under the inner open volume.
> Nowicki has most of the good work on focussed sunlight entry in
> print, and Clarke definately originated the "light emmiter" slit or
> spot on the opposite landscape floor (albeit using rather "soft" S.F.
> artificial energy & light).
>
> > At first, as usual, I thought about mirrors inside the colony to
> disperse the incoming sunlight in a useful way. But after a while I
> thought: wouldn't simply making the sunlight hit an opaque and purely
> white surface be a simpler and cheaper alternative to a mirror system?
>
> How about a polished, but pebbled-textured aluminum surface?
> (pebbled texture, to diffuse the light, but polished for efficient
> reflection)
> Overall, this sounds a little like the "hatbox" design, or
> the "sunflower". Redirect the sunlight to the land surface, after
> it's already been reflected into the hab volume.
>
> I take it the polished reflecting surface is an end cap? Remember
> that dust won't settle onto it: It's vertical with referrence to
> local gravity, and the gravity is nil.
>
> With referrence to the light ducts, why not just have a small "Rama"
> type hole or spot in the landscape, which shines light onto a broad
> area of landscape overhead?
> We don't know about the intensity of sunlight needed to be piped in
> through a duct, and we don't know about the intensity of convergent
> beams of light in the center of the hab.
>
> Any of these design options are high maintenance (but so are the
> huge, fragile, rotating exterior mirrors of O'Neill's designs).
> The "Island One" Bernal sphere comes closest to any of these ideas:
> small window area, with most mirror being non-rotating.
>

--
Al Globus
aglobus@..., (650) 604-4404
http://www.nas.nasa.gov/~globus/home.html

The dinosaurs weren't spacefaring. We are. I don't think that's an
accident.
Maybe we are life's taxi to the stars. Let's start with space tourism,
and
graduate to orbital colonies.