Hi,

>I'm not sure if you're making a statement of fact or asking a
>question.

Statement. The smaller an open system is, the more reliant it is on
external resources. The smaller a closed system is, the soon it will fail,
moreso if people are in it.

>First off what do you mean by a sustainable ecosystem?

a diverse self-maintaining open system with the ability to buffer against
fluctuations in the environment and adapt to changing conditions from
external sources.

A small closed system is not adequate for long-term survival. Not if humans
are included. Toxins build up, technology fails.

>Secondly, perhaps humans can live in a ecosystem that only meets
>their needs

Technological or survival?
Technological needs require an industrial complex, to produce spare parts
for maintenance. It consumes significant energy and material resources and
produces a lot of waste. There is only so much that can be recycled before
new resources are required.

Survival needs require a biodiverse ecosystem, capable of supporting human
needs and recycling human wastes, while stopping toxins from building up.
Diversity is essential to buffer against environmental changes. What if
people relied on a handful of species for food and those species died out?

Bananas are the perfect example.
Bananas are a main source of food for a fifth of the world's population .
Yet the banana is likely to be extinct in the next 20 years. Almost all
Bananas are grafted from a parent tree. They are rarely grown from standard
pollen-based sexual reproduction. Except for a few mutations they are
virtually clones, selectively bred to produce the largest bunches. The
species has no genetic diversity. Rust molds are currently decimating
banana crops in third-world countries. Because there is no genetic
diversity in the species, all the individual trees are susceptible and die.
It is only a matter of time before the rusts infect bananas in first-world
countries and the species dies out, except maybe in the wild where is
continues to reproduce by pollen.

How many other food species, that we rely on, are selectively breed for
only one trait? The juiciest watermelons, highest-yield wheat, largest cobs
of corn, crispiest apples, the fatest chickens, the leanest beef. Certainly
the changes are good for us but in doing so we reduce the genetic diversity
of those species, or worse, we force speciation. Speciation is where a
small group of one species is isolated and so pressured from external
sources that it forms a sub-species and later it's own species. This
disconnects the group from the genetic diversity in it's progenitor
species. Only through mass sexual reproduction, mutations and significant
die off does the group regain the genetic diversity needed for long-term
survival.

It's interesting to note: every human alive today is descended from one of
only five females. We have already undergone the stage of mass sexual
reproduction, our population grew exponentially. We're now reaching the
limit of our resources. Our use of nuclear energy and synthetic chemicals
are producing mutations at an alarming rate. It seems the next stage for us
is a significant die off. Assuming of course we don't expand to other
planets and form new sub-species there.

>Considering the population density we'll probably have, I'd compare it to the
>ecosystem needed to keep NYC going. Not much NEED for bee, birds, trees,
>lakes,
>rivers, savanah, etc.

NYC is the perfect example of an unsustainable ecosystem. It doesn't
produce it's own food and can't process it's own waste. It is totally
reliant on surrounding systems to survive.

The birds and the bees are needed for the pollination of our food species.
Without them our food will loose it's genetic diversity, or not grow at
all. Trees are needed to keep the water table down, provide breeding and
resting sites for the birds, and convert CO2 into O2. Lakes and rivers
(large bodies of water) are needed to buffer against temperature
fluctuations, and store water for the crops and provide drinking water for
birds, bees and people.

I have to say, a majority of city people just don't realise how dependant
they are on farms, and nature in general. Perhaps this is why there is so
much missunderstanding about the essential need of biodiversity in future
space settlements.

>I think the correct figure you meant to quote was 6 ft of dirt
>around the shell of smaller Habitats will approximate the radiation
>dosage equivalent to Denver. Can anybody else backstop me on this?

I've checked. It's 14 feet of concrete, a few feet of lead or a planetary
atmosphere. Apparently the rare-earth elements do a better job but they are
too rare to use in large scale structures.

>For the larger Habitats, usually the thickness of the pressure shell
>and the thickness of the atmosphere is sufficient protection.

How thick are you talking?

>I'm not sure how you mean that the thermal conditions of the
>atmosphere is prone to catastophic failure?

In a closed system temperatures can rise quickly, too quickly for
air-conditioning to extract the heat. Sudden temperature increases, such as
house fire, in a space settlement can have a major system-wide impact
whereas on a planet the impact is localised and the system as a whole
continues to function and recovers easily.

>Sometimes it takes a new way of looking at the problem to find the solution.

Solutions are what we need. Discussion is the best way to start.

Michael :]

--- In spacesettlers@yahoogroups.com, Michael wrote:
> Hi,
>
> >I'm not sure if you're making a statement of fact or asking a
> >question.
>
> Statement. The smaller an open system is, the more reliant it is on
> external resources.

So?

The smaller a closed system is, the soon it will fail,
> moreso if people are in it.

No, the people are there to keep it operating. The Earth's ecosystem
is unmanageable, whereas the Habitat's would be under our control.
Much better not to have to deal with floods, hurricanes, tornados,
droughts, global warming, blizzards, earthquakes, pollution, etc.

> A small closed system is not adequate for long-term survival. Not
if humans
> are included. Toxins build up, technology fails.

Which toxins?

Humans are there to maintain and improve the technology overseeing
the eco-system.

> >Secondly, perhaps humans can live in a ecosystem that only meets
> >their needs
>
> Technological or survival?
> Technological needs require an industrial complex, to produce
spare parts
> for maintenance. It consumes significant energy and material
resources and
> produces a lot of waste. There is only so much that can be
recycled before
> new resources are required.

That's why a close enough system is fine. To strive for a closed
system is admirable, but not necessary.

Energy use in orbit is on a different calculus than here on Earth.

The industrial complex is a necessary precursor to large habitats in
orbit.

>
> Survival needs require a biodiverse ecosystem, capable of
supporting human
> needs and recycling human wastes, while stopping toxins from
building up.
> Diversity is essential to buffer against environmental changes.
What if
> people relied on a handful of species for food and those species
died out?

As I noted in my secondary post to you, sometimes thinking in the
same paradigm leads you nowhere. Look at Leonardo modeling birds as
the route to human flight. He missed the airfoil and other concepts.
If you only accept the proposition that a planetary ecosytem can
support human life then you'll always reach the tautological
conclusion that planetary scale ecosystems are needed to support
human life.

Survival doesn't require a biodiverse ecosystem, just the products
that it produces. Recycling human wastes can be done with technology
and energy.

If specific toxins are identified then means to negate their adverse
affects can be designed.

Diversity is NOT required as a buffer against environmental changes.
In an Island 3, there would be hundreds of isolated ecosystems, each
tailored to specific conditions. The odds of each failing
independently and simultaneously are pretty darn long.

>
> Bananas are the perfect example.
> Bananas are a main source of food for a fifth of the world's
population .
> Yet the banana is likely to be extinct in the next 20 years.
Almost all
> Bananas are grafted from a parent tree. They are rarely grown from
standard
> pollen-based sexual reproduction. Except for a few mutations they
are
> virtually clones, selectively bred to produce the largest bunches.
The
> species has no genetic diversity. Rust molds are currently
decimating
> banana crops in third-world countries. Because there is no genetic
> diversity in the species, all the individual trees are susceptible
and die.
> It is only a matter of time before the rusts infect bananas in
first-world
> countries and the species dies out, except maybe in the wild where
is
> continues to reproduce by pollen.

Good point. This just adds to the urgency of establishing Habitats.
In the Habitat, each little agricultural pod can have an isolated
ecosystem with optimum conditions for the flora within. With
Habitats established we could foreverafter rest easy about the very
banana situation you've described.

Speciation is where a
> small group of one species is isolated and so pressured from
external
> sources that it forms a sub-species and later it's own species.
This
> disconnects the group from the genetic diversity in it's progenitor
> species. Only through mass sexual reproduction, mutations and
significant
> die off does the group regain the genetic diversity needed for
long-term
> survival.

I haven't come across any High Frontier advocates espousing the
position that we should establish ourselves, get our ecosystems
functioning, and then cut off all seed, animal and human
importation. I think that there will be a continuous genomic cross
fertilization betwen Earth and Orbit.

>
> It's interesting to note: every human alive today is descended
from one of
> only five females.

It is indeed interesting. See the "Journey of Man" TV documentary
from National Geographic and broadcast on PBS. Details man's journey
out of Africa and the establishment of the Australian Aboriginies,
the Central Asian populace, then European, North Arctic, and
finally, North American aboriginals. Many of these populations were
started by only a handful of individuals.

We have already undergone the stage of mass sexual
> reproduction, our population grew exponentially. We're now
reaching the
> limit of our resources.

Are we? There are many resources in orbit. Think beyond the closed
system mentality that afflicted the Club of Rome crowd in the 1960s
and 1970s.

Our use of nuclear energy and synthetic chemicals
> are producing mutations at an alarming rate.

Better to rush and create Habitats so that our ecosystems can be
isolated from these dangerous mutations.

It seems the next stage for us
> is a significant die off.

No. The next stage is to expand to orbit.

Assuming of course we don't expand to other
> planets and form new sub-species there.

Planets are the worst place to base an advanced civilization. You
know, I've heard that somewhere before :)

Besides, what other planets? The ones we have in the solar system
don't make any economic sense.

> >Considering the population density we'll probably have, I'd
compare it to the
> >ecosystem needed to keep NYC going. Not much NEED for bee, birds,
trees,
> >lakes,
> >rivers, savanah, etc.
>
> NYC is the perfect example of an unsustainable ecosystem. It
doesn't
> produce it's own food and can't process it's own waste. It is
totally
> reliant on surrounding systems to survive.

That's why I chose the example. The ecosystem of the Habitat
dedicated to human habitation can be isolated from the agricultural
sections.

The waste stream in a Habitat can be handled more easily in orbit by
the use of large amounts of energy. This isn't feasible on Earth
because of the cost of energy.

>
> The birds and the bees are needed for the pollination of our food
species.

If the Habitat citizens don't want genetically engineered good then
they can bring in the birds and the bees into each agricultural
pods, let them do their thing, and then collect them and bring them
to the next pod.

> Without them our food will loose it's genetic diversity,

Not with human intervention close at hand. And we're not precluding
the presence of bees.

or not grow at
> all. Trees are needed to keep the water table down,

The water that percolates through the Habitat soil can be collected
beneath ground, channeled towards storage and filtration, and
redeployed.

provide breeding and
> resting sites for the birds,
and convert CO2 into O2.

So we have trees within the human section of the Habitat.

Lakes and rivers
> (large bodies of water) are needed to buffer against temperature
> fluctuations, and store water for the crops and provide drinking
water for
> birds, bees and people.

And for aesthetics too. The temperature can be buffered by limiting
the strength and duration of sunlight permitted within the Habitat.
Try that on Earth.

>
> I have to say, a majority of city people just don't realise how
dependant
> they are on farms, and nature in general.

That's true they don't.

Perhaps this is why there is so
> much missunderstanding about the essential need of biodiversity in
future
> space settlements.

Many, many people have looked into this but they look for solutions
rather than trying to fit a favored model to a scenario that doesn't
require that model.

I see what you're trying to argue but I hope my answers to your
questions make clear that I don't accept the same starting
proposition that you do, namely that we need to recreate process and
scale in order to have a functioning ecosystem.

> >I think the correct figure you meant to quote was 6 ft of dirt
> >around the shell of smaller Habitats will approximate the
radiation
> >dosage equivalent to Denver. Can anybody else backstop me on this?
>
> I've checked. It's 14 feet of concrete, a few feet of lead or a
planetary
> atmosphere. Apparently the rare-earth elements do a better job but
they are
> too rare to use in large scale structures.

I'm going to call you on this one. I need some supporting
documentation that I can assess for myself for your figures fall far
out of line of everything I've seen.

> >For the larger Habitats, usually the thickness of the pressure
shell
> >and the thickness of the atmosphere is sufficient protection.
>
> How thick are you talking?

Four miles in diameter.

> >I'm not sure how you mean that the thermal conditions of the
> >atmosphere is prone to catastophic failure?
>
> In a closed system temperatures can rise quickly, too quickly for
> air-conditioning to extract the heat. Sudden temperature
increases, such as
> house fire, in a space settlement can have a major system-wide
impact
> whereas on a planet the impact is localised and the system as a
whole
> continues to function and recovers easily.

You'll have far fewer combustibles in orbit. Forget about homes
constructed of lumber. Even if the joules output from a localized
fire were high the volume of atmosphere could absorb it and the heat
could be mechanically radiated away. This can't be done on Earth.

> >Sometimes it takes a new way of looking at the problem to find
the solution.
>
> Solutions are what we need. Discussion is the best way to start.
>
> Michael :]

I'm with you on that. LOL. Seriously, O'Neill and the other High
Frontier advocates weren't dummies. They've made their case very
well, IMHO, and I can't see any flaws in the models. You just have
to cast off the planetary chauvinism and see them in a fresh light.

TangoMan

--- In spacesettlers@yahoogroups.com, "victoriatangoman"
wrote:
> --- In spacesettlers@yahoogroups.com, Michael
> > >I think the correct figure you meant to quote was 6 ft of dirt
> > >around the shell of smaller Habitats will approximate the
> radiation
> > >dosage equivalent to Denver. Can anybody else backstop me on
this?
> >
> > I've checked. It's 14 feet of concrete, a few feet of lead or a
> planetary
> > atmosphere. Apparently the rare-earth elements do a better job
but
> they are
> > too rare to use in large scale structures.
>
> I'm going to call you on this one. I need some supporting
> documentation that I can assess for myself for your figures fall
far
> out of line of everything I've seen.

>From what I can recall, five meters of concrete will give you the
same radiation exposure as sea level on a cloudy day. Two meters is
more like being in a jet plane at 40000 feet.

>
> > >For the larger Habitats, usually the thickness of the pressure
> shell
> > >and the thickness of the atmosphere is sufficient protection.
> >
> > How thick are you talking?
>
> Four miles in diameter.

That doesn't say how thick the pressure shell would be.

Ed

--- In spacesettlers@yahoogroups.com, "Ed Minchau"
wrote:
> --- In spacesettlers@yahoogroups.com, "victoriatangoman"
> wrote:
> > --- In spacesettlers@yahoogroups.com, Michael
> wrote:
> > > >I think the correct figure you meant to quote was 6 ft of dirt
> > > >around the shell of smaller Habitats will approximate the
> > radiation
> > > >dosage equivalent to Denver. Can anybody else backstop me on
> this?
> > >
> > > I've checked. It's 14 feet of concrete, a few feet of lead or
a
> > planetary
> > > atmosphere. Apparently the rare-earth elements do a better job
> but
> > they are
> > > too rare to use in large scale structures.
> >
> > I'm going to call you on this one. I need some supporting
> > documentation that I can assess for myself for your figures fall
> far
> > out of line of everything I've seen.
>
> From what I can recall, five meters of concrete will give you the
> same radiation exposure as sea level on a cloudy day. Two meters
is
> more like being in a jet plane at 40000 feet.

Quote from "Colonies in Space" by T.A. Heppenheimer, page 229,
Warnerbooks paperback edition, 1977;

"The six feet of covering will absorb all cosmic rays as well as
most secondary particles. A few of the most energetic particles will
produce so many secondaries that some will reach the colony, but
there will be no problem with solar flares, even the biggest, and no
problem with the iron nuclei in cosmic rays. Babies and mothers will
live amid radiation levels no higher than those in Denver or in some
of the cities in northern Arizona."

> >
> > > >For the larger Habitats, usually the thickness of the
pressure
> > shell
> > > >and the thickness of the atmosphere is sufficient protection.
> > >
> > > How thick are you talking?
> >
> > Four miles in diameter.
>
> That doesn't say how thick the pressure shell would be.
>
> Ed

That's a standard engineering formula. The answer depends on the
tensile strength of the material you choose, the shape of the
vessel, the atmospheric pressure to be contained, the other loads
that have to be carried, and the vessel's diameter.

The essential point is that the combination of the pressure shell
and the atmosphere serve as a means of radiation protection.

TangoMan

On Sunday, September 21, 2003, at 07:17 PM, Michael wrote:

> Bananas are a main source of food for a fifth of the world's
> population .
> Yet the banana is likely to be extinct in the next 20 years.

Do you have any idea how many predictions like this have been dead
wrong? For examples, stick to what has actually happened, not just
someone's prediction. It's much more convincing.

The materials in one asteroid (the largest ) are sufficient to make
orbital space colonies with ~150 times the surface area of the Earth in
usable real estate. See http://lifesci3.arc.nasa.gov/SpaceSettlement/
for details.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Views expressed in this email are only my opinions and are not the
position of any organization I'm familiar with.

--- In spacesettlers@yahoogroups.com, Al Globus wrote:
>
> On Sunday, September 21, 2003, at 07:17 PM, Michael wrote:
>
> > Bananas are a main source of food for a fifth of the world's
> > population .
> > Yet the banana is likely to be extinct in the next 20 years.
>
> Do you have any idea how many predictions like this have been dead
> wrong? For examples, stick to what has actually happened, not
just
> someone's prediction. It's much more convincing.

I agree. I'm on Arthur C. Clarke's side on this. He said "When a
distinguished but elderly scientist says that something is possible,
he is almost certainly right. When he says it is impossible, he is
very probably wrong."

I think science is most interesting when it is trying to expand
horizons not restrict them. There'll always be some young whipper-
snapper who comes along and figures out how to do the impossible,
like fly an airplane, propell an object in space, withstand the
awesome forces of trains going faster than 30 m.p.h., or developing
the "Green Revolution" to feed the world's people.

TangoMan