> > > a first model habitat would be [...] quite expensive.
> > What makes you say that? I have been estimating a shell cost
> > on the order of $1/sqft of commercially-viable floor-space.
> I'd like to see your figures. That sounds too low to me.
I am assuming that the non-marginal costs would be trivial. $1/sqft
assumes a relatively brittle design, e.g. post-tensioned. For a
relatively ductile design, e.g. no post-tensioning and a lot of PVA
fibers in the mix, the cost would be closer to $10/sqft.
Here is the main material:
http://www.kuraray-am.com/pvaf/pva-ecc.php
"Physically and mechanically, ECC behaves like normal concrete.
Under tension, however, ECC behaves more like a ductile metal."
At a typical fiber-fortification volume of 2%, the mass of fiber
per cubic yard of "concrete" would be ~44 lbs. In small volumes,
the fiber costs ~$3/lb. I am assuming that in colossal volumes the
fiber might drop in cost to around $1/lb.
Utilizing a mix incorporating high-volumes of fly-ash (HVFA), can
save money since the Portland cement requirement is thus reduced.
Two recent papers on this (full-text links):
http://ace-mrl.engin.umich.edu/NewFiles/journals(current).html
"Use of High Volumes of Fly Ash to Improve ECC Mechanical
Properties and Material Greenness"
"Engineered Cementitious Composites with High-volume Fly Ash"
> > I was thinking that controlling the day/night cycle would be a
> > compelling feature anywhere.
> Why?
The world is moving toward an economy of pure information.
http://www.juliansimon.com/writings/Ultimate_Resource/TCHAR33.txt
"From an economic point of view, the good that we may call truth-and
beauty is conceptually no different than raw materials such as grain,
or processed goods such as services and manufactured products. As
information and knowledge constitute an ever-larger part of our
economy with every passing year, and tangible goods (especially
natural-resource materials, including energy) become an ever-smaller
share of inputs, there should be less and less difficulty in agreeing
that truth-and-beauty -- call it art, if you like -- is a good which
may be construed theoretically in ways similar to the ways we
construe other economic goods. A key respect in which truth-and-
beauty is like knowledge, and thereby like the supply of natural
resources that flows from knowledge, is that our stocks of both sorts
of intellectual goods are not depleted by use, but instead continue
forever to enhance human life."
In an information economy, control over natural cycles represents a
valuable resource.
> > For Stage-2, the simulated-isolation stage, I was thinking of
> > the High Desert in Nevada. Maybe Colorado would be a better
> > choice,since it is closer to space.
> I happen to live in Colorado. Such a domed city would never
> catch on here
Stage-2 would be the *simulated-isolation* stage, and therefore
would not be sold to locals. The idea would be that, once the
general concept of a million-man city-in-a-single-building were
proven, folks (space-colonization fans) who thought that they
were ready to move into space would be invited to participate in
a group trial-run called Stage-2 -- a colossal Earth-based
isolation-simulator. For accurate simulation, data-transfers
would incorporate artificial latency, cargo transfers would be
expensive and slow, and, of course, no one inside would be
allowed to go outside.
It would not be Biosphere-2, though. Any resident at any time
could stop the experiment by crying "Uncle", conditions would then
be reset with engineered improvements, and the experiment would
be run again. This iterative process would continue until the city
could demonstrate itself internally-stable over a reasonably long
period.
> we love our great outdoors too much (and both the weather and
> the day/right cycle are mild).
Oh.
http://space.mike-combs.com/wannabe.htm
"The first few generations in space will live a hard, dangerous,
confined life under conditions that will make Alcatraz seem like a
spa resort. [...] What kind of American, or indeed Westerner, would
give up a life on humdrum ol' Earth to live the rest of his life in
cramped, uncertain, unpleasant conditions? [...] the romance of
pioneering in space will wear off real quick once the public realises
there are no holodecks, or green bountiful parks in moon domes, or
exciting battles with fierce alien invaders, just 10 cubic meters of
cramped quarters, recycling your own urine, living in your own sweat,
facing the dangers of decompression daily, seeing the same goddamn
faces every day,knowing that down below on Earth people are laughing,
and loving, breathing fresh air and running in spring sunshine,
meeting people and living life."
It's interesting that Robert Heinliens story "The Moon
is a Harsh Mistress" anticipated the unpleasant
aspects of the high frontier by analogy with the
Australian penal colony and came to the conclusion
that mainly those with nothing to lose would be the
most likely to settle such an adverse environment.
HAving said that I hasten to note, the current
political/economic environment will likely continue to
create a growing "under class", a large pool of
desperate people who might seek solace in such a
difficult environment as the early high frontier. Not
everyone in the western world is rich,,,
> > > > a first model habitat would be [...] quite
> expensive.
> > > What makes you say that? I have been estimating
> a shell cost
> > > on the order of $1/sqft of commercially-viable
> floor-space.
> > I'd like to see your figures. That sounds too low
> to me.
>
> My estimates are based purely on the
> placed-materials costs, since
> I am assuming that the non-marginal costs would be
> trivial. $1/sqft
> assumes a relatively brittle design, e.g.
> post-tensioned. For a
> relatively ductile design, e.g. no post-tensioning
> and a lot of PVA
> fibers in the mix, the cost would be closer to
> $10/sqft.
>
> Here is the main material:
> http://www.kuraray-am.com/pvaf/pva-ecc.php
>
> "Physically and mechanically, ECC behaves like
> normal concrete.
> Under tension, however, ECC behaves more like a
> ductile metal."
>
> At a typical fiber-fortification volume of 2%, the
> mass of fiber
> per cubic yard of "concrete" would be ~44 lbs. In
> small volumes,
> the fiber costs ~$3/lb. I am assuming that in
> colossal volumes the
> fiber might drop in cost to around $1/lb.
>
> Utilizing a mix incorporating high-volumes of
> fly-ash (HVFA), can
> save money since the Portland cement requirement is
> thus reduced.
> Two recent papers on this (full-text links):
>
http://ace-mrl.engin.umich.edu/NewFiles/journals(current).html
>
> "Use of High Volumes of Fly Ash to Improve ECC
> Mechanical
> Properties and Material Greenness"
>
> "Engineered Cementitious Composites with High-volume
> Fly Ash"
>
> > > I was thinking that controlling the day/night
> cycle would be a
> > > compelling feature anywhere.
> > Why?
>
> The world is moving toward an economy of pure
> information.
>
http://www.juliansimon.com/writings/Ultimate_Resource/TCHAR33.txt
> Oh.
> http://space. mike-combs. com/wannabe. htm
cylinders? Don't get fooled by the ads. They will come, but the first
couple of space-borne generations will have to build 'em.
And the abovewas one reason why I decided this somewhat-acidic posting was still worthy of being featured on my site. He wasn't dogmatically denying that life in orbit would ever look like the pleasant artist's conceptions we've seen. He's just pointing out that it won't start out that way. And I don't think any sensible person assumes otherwise.
I feel that a perception of being "outdoors", with natural insolation,weather,and day/night cycle will be important features for space habitats if we have any desire for them to becomeglobally relevant. Without these features,theywill remainan option only for a very few hardy souls willing to live lives of relative deprivation for the idealistic goal of expanding human presencebeyond the Earth. With such features, they become an option for many millions of ordinary Earthlings who may have no motivation other than pursuit of economic opportunities.
Regards,
Mike Combs
> , the current
> political/economic environment will likely continue to
> create a growing "under class", a large pool of
> desperate people who might seek solace in such a
> difficult environment as the early high frontier. Perhaps, but I fear the vast expansion of the welfare state we've seen in too many countries might act todouse the fire of this trend.
Mike Combs
The welfare state provides a barely minimal living
standard. Anyone trapped in such conditions but
possessing the least intellectual attribute might
possibly be attracted to the bare possibility of an
improvement(eventually) of their condition. Then we
have the political aspect, wherein society provides
the transport for "those lazy welfare bums" in order
to get them off the dole and receive some return on
our social investment. Since the USA has the highest
percentage of our population in prison of ANY
industrialized nation, it could be argued that a good
place for the non-violent criminals is the lunar
mining conglomeration with perhaps, as an incentive to
"be good", a reduction in the miscreants sentence, if
they remain on the moon and continue contributing to
the social fabric by helping build solar power sats.
For those social offenders, it could be argued they
could improve their economic condition in such an
environment. Hey, it worked for the Aussies,,,