On 2/10/2015 10:56 PM, green wrote:
> certain features of your design need attention drawn to i think.
>    having a non-rotating nacelle over the rotating pseudo-gee habitat can provide
> for shielding.  figure up to two meters of concrete/regolith/plastic.  with the
> shielding separate from the hab, you do not have to invest in the angular
> momentum.  however, your design is a 'long tom'; rotating cylinders on such a
> long axis are inherently unstable and will seek to precess to a rotation around
> a more stable principle axis, with disastrous results.  the instability can be
> overcome i think by carefully orchestrated counterweights moving radially from
> the axis of rotation, but clearance with your nacelle might be a problem.  most
> designs that deal with the stability problem just make the cylinder shorter,
> more like 'square', diameter=length.  'kalpana one' is such a design; it is near
> the size of yours.

I added a new outer ring for the solar panels and agridomes. They rotate 
in the opposite direction as the habitat. But they have very little mass.


>    if you intend to have near-earth-strength artificial illumination, then
> consider the basic efficiency of photon-in (to the solar cell) vs photon-out
> (from the lighting).  ten percent is ridiculously high i suspect; but that would
> mean having ten times the surface area of your hab in solar cell area, just for
> lighting alone.  usually this problem is solved with natural sunlight and
> mirrors.  a good example is the o'neill-type cylinders in alexis gilliland's
> 'rosinante' trilogy (available for kindle).  instead of giant whirling plane
> mirrors (at ten or twenty gees at the tips) gilliland embeds the habs in vast
> conical arrays of small mirrors, each steerable.  as a bonus, since the mirrors
> are stationary, they can be heavy, and are dichroric mirrors reflecting only
> visible light, no heat or u.v.   also, since the novels are set in the asteroid
> belt, much larger surface areas are needed than can be provided by the mirrors
> of the classic o'neill cylinder.

The ship has a regular reactor in addition to the solar panels. It's in 
the center of the big sphere that's kind of hard to see now. It's 
surrounded by water and fuels maybe. Maybe cargo.


>    you can hypothesize food plants that thrive in zero gee but that is a big leap
> of faith.  the classic o'neill cylinder had a ring of 'small' 'farm modules' to
> feed the cylinder (the gilliland habs were in the business of agriculture).  the
> o'neill farms were rotating structures about the size of your spinner.  even
> stipulating zero gee crops, i am wondering, why the domes instead of flat
> coverings (tho they do look cool).  radiation protection is another concern; i
> have forgotten if o'neill's 'high frontier' addressed it.  in a 'current state
> of the art' pragmatic cop-out, it might be necessary to move agriculture into
> the main hab, send everybody 'underground'.  coolness counts, tho, and every
> design feature, or bug, can be rationalized away.

The agridomes are rotating now, so they should have proper fake gee. I 
was thinking the dome shape would resist pressurization better. They're 
not well shielded though. I haven't modeled the parabolic torus (a 
surface, not a solid) yet to collect light and direct it to the domes.


> i fear my ideas seem limiting and stifling whereas i hope they inspire and help.
>   there are a lot of divergent ideas out there, and that is a good thing.

Thanks for your comments! Keep them coming!

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