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Questions about "The High Frontier"



 
 
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  #31  
Old October 3rd 07, 05:59 AM posted to rec.arts.sf.science,sci.space.history
Pat Flannery
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Default Questions about "The High Frontier"



Johnny1a wrote:
O'Neill's plan called for totally unrealistic space access by the
standards of the 70s, he was assuming not only that the Space Shuttle
would live up to NASA's hype, but that it would do _better_ over time,
and he was assuming radically unrealistic constructions costs at every
stage of the game, including assuming the availability of working
models of technology that just hadn't been proven yet (and much of it
still hasn't been.)


He also assumed the development of huge reusable heavy lift boosters if
the SPS constellation was to be built using Earth-launched materials,
and if it ever is built, that's almost certainly the way it will be
done, rather than going to all the trouble of building the Lunar
infrastructure.
What really makes me a critic, though, is not that O'Neill dreamed
big, I admire that. The problem is that his dreams became so hyped
that they actually became a negative force from a POV of space
exploration and development. Critics used them as 'proof' that the
entire concept of space exploration/exploitation was silliness, empty
pipe dreams, while they raised supporters expectations to levels
guaranteed to be disappointed.


That probably had a lot to do with the enthusiasm shown by the aerospace
industry for the concept; they full-well knew that the thing was wildly
optimistic...but on the offhand chance it would get funded, they were
willing to to play it up as a brilliant idea, because it would make the
Apollo program look like a minor project by comparison.

Pat
  #32  
Old October 3rd 07, 06:07 AM posted to rec.arts.sf.science,sci.space.history
Pat Flannery
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Default Questions about "The High Frontier"



Jim Davis wrote:

Why would just the athletes flee? Why not everyone else? Are only the
athletes' lives in danger? Why aren't people fleeing now?



They can't. Their lead content is so high that they've become immobile
due to their mass. Even their pet dogs have been crushed flat under
their own weight: http://tinyurl.com/cftp

Pat ;-)
  #33  
Old October 3rd 07, 06:26 AM posted to rec.arts.sf.science,sci.space.history
Pat Flannery
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Default Questions about "The High Frontier"



Johnny1a wrote:
Population growth is a _good_ thing in the long term, survival-wise,
population decrease is a sign of a declining society and even stablity
is death in the long haul. Survival _requires_ growth and expansion,
because sooner or later something unlikely in the short term but near-
certain the long will do bad things to any given habitat.


Population growth on Easter Island wasn't a good thing, nor in many
areas where it led to soil depletion via overfarming to support a
burgeoning population throughout human history.
I did the math on this once, there were around 8.5 city blocks per
person for everyone on the face of the planet, and that included using
the seas as surface area also:


that this is the total surface area of the Earth, not just the land
masses:
"Here's another way of looking at it; the total world population is
around 6,490,115,551 as of this morning:
http://www.census.gov/main/www/popclock.html
The total surface area of the earth is 196,940,400 square miles:
http://pages.prodigy.net/jhonig/bignum/qland2.html
So if we take divide that population by that surface area we end up with
an average of around 33 people per square mile of the Earth's surface.
Now there are a total of 27,878,400 square feet in a mile, so we end up
with one person for around every 844,800 square feet of the Earth's
surface, or to put it another way, around one person for every 8.5 city
blocks, which although they vary wildly in size tend to cover around
100,000 square feet total on average (assuming they are a tad over 300
feet on a side)


Take the oceans out of that equation and you are starting to get near
the point where we have only enough area to support our total population
via farming, particularly when areas unsuitable for farming (mountains,
forests, deserts) are taken into the equation.
When you move out into space in any large numbers, the amount of area
required for food production starts to look pretty daunting,
particularly if you want a varied diet including things like meat and
cheese, although I imagine a lot of things could be made in a synthetic
form.

Pat
  #34  
Old October 3rd 07, 06:42 AM posted to rec.arts.sf.science,sci.space.history
Troy
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Default Questions about "The High Frontier"


The primary requirement for a space habitat is to provide a pressurized
environment. That takes lots of tensile strength. Regolith has little or
no tensile strength and even solid rock doesn't have enough. Even glass is
much better, and steel and aluminum more so. So if we wind up building a
steel or aluminum shell inside the asteroid to provide the pressurized
environment, we have to ask what is the asteroid providing. Radiation
protection? Fine, but we can get that with a shell no more than 6 feet
thick. If we remove a certain amount of raw materials from the asteroid and
refine it to glass, steel, and aluminum, the left-over slag is sufficient
material for that 6 foot thick radiation shield.


The concept I was thinking of is Niven's asteroid balloon. Take an
iron asteroid, place water tanks at the centre, spin asteroid on its
axis and bathe with concentrated sunlight from a solar mirror. Tank
explodes, inflates molten steel asteroid into a large habitat. Most
asteroids are just soft rubble piles anyway; they'd fly apart if you
spun them any faster than once every 2 hours. Some sort of melting has
to be done on the outer shell to stop one disintegrating;
additionally, internal structural bracing such as steel cables are
required to hold it together, especially if you want nice amenities
like dirt and artificial gravity.

O'Neill also mentioned spray-on space-based structures. That could do
nicely for manufacturing large (100m) habitat modules. However, the
Island One design is wildly extravagant - it would take many decades
of settlement for habitats to become anything like comfortable.

Yes, I'm entirely open to the idea that space habitats, instead of springing
full-blown from a single project as O'Neill envisioned, might evolve as a
series of incremental improvements to space hotels. We get to the 10th
generation space Hilton, with its rotation for artificial G, its full
radiation shielding, its closed ecology, and perhaps even use of natural
sunlight, and people will suddenly go, "Hey, this is like that old Island
One notion O'Neill was talking about back in the 20th Century".

--

Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn



  #35  
Old October 3rd 07, 06:52 AM posted to rec.arts.sf.science,sci.space.history
Erik Max Francis
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Posts: 345
Default Questions about "The High Frontier"

Troy wrote:

The concept I was thinking of is Niven's asteroid balloon. Take an
iron asteroid, place water tanks at the centre, spin asteroid on its
axis and bathe with concentrated sunlight from a solar mirror. Tank
explodes, inflates molten steel asteroid into a large habitat. Most
asteroids are just soft rubble piles anyway; they'd fly apart if you
spun them any faster than once every 2 hours. Some sort of melting has
to be done on the outer shell to stop one disintegrating;
additionally, internal structural bracing such as steel cables are
required to hold it together, especially if you want nice amenities
like dirt and artificial gravity.


This has always struck me as implausible. It's hard to see how most, or
even a few, nickel-iron asteroids would be uniform enough to make this
work without just fracturing during the process, wrecking the whole
enterprise.

--
Erik Max Francis && && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM, Y!M erikmaxfrancis
Come not between the dragon and his wrath.
-- Shakespeare, _King Lear_
  #36  
Old October 3rd 07, 07:20 AM posted to rec.arts.sf.science,sci.space.history
Eivind Kjorstad
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Posts: 34
Default Questions about "The High Frontier"

Jonathan skreiv:

There's a huge and glaring logical flaw with the idea of large
scale colonies in space. If we can't learn how to sustain ourselves
here on earth, with all the natural advantages and cheap resources.


We have, infact, been sustaining ourselves here on earth for quite a
while already thankyouverymuch. We've known how to do that trick since
literally the first day a human ever walked the earth. If we hadn't,
we'd be extinct by now.

Infact we've done a lot more than merely "sustain" ourselves. We've
spread and colonized every continent and just about every corner of
every continent. There is no other large mammal that even comes close to
being so widespread (I didn't say "numerous", though I suppose that may
-also- be true if we count only animals with an adult mass above 50kg)

Seems to me, by "sustain", you mean something different from sustain.
Perhaps you mean that unless we can live with no influence on the world
around us whatsoever, we're not "sustaining" ourselves. By that
definition no species has ever been able to "sustain" itself anywhere.

The true test of an enlightened civilization is to be able
to sustain itself indefinitely. Not to simply find more room
for unsustainable societies.


Both makes sense. Everyone here agrees that it's /easier/ living on
earth than elsewhere. But that's a bit like saying it's /easier/ living
in Italy than in northern Scandinavia, so it makes no sense for anyone
to be doing the latter. That is a strange kind of reasoning.

Why do sci-fi writers assume we must move into space to survive???


Most don't.



Eivind Kjørstad
  #37  
Old October 3rd 07, 07:48 AM posted to rec.arts.sf.science,sci.space.history
Logan Kearsley
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Posts: 14
Default Questions about "The High Frontier"

"Erik Max Francis" wrote in message
t...
Troy wrote:

The concept I was thinking of is Niven's asteroid balloon. Take an
iron asteroid, place water tanks at the centre, spin asteroid on its
axis and bathe with concentrated sunlight from a solar mirror. Tank
explodes, inflates molten steel asteroid into a large habitat. Most
asteroids are just soft rubble piles anyway; they'd fly apart if you
spun them any faster than once every 2 hours. Some sort of melting has
to be done on the outer shell to stop one disintegrating;
additionally, internal structural bracing such as steel cables are
required to hold it together, especially if you want nice amenities
like dirt and artificial gravity.


This has always struck me as implausible. It's hard to see how most, or
even a few, nickel-iron asteroids would be uniform enough to make this
work without just fracturing during the process, wrecking the whole
enterprise.


There is another way to do an asteroid balloon that doesn't require the
asteroid to be anywhere near uniform, nor for you to drill into it (although
doing so would probably help).
Put a balloon (mylar, perhaps) around the asteroid, and fill it with carbon
monoxide. Get it warm and circulating. Then heat the balloon surface to
deposit nickel and iron from carbonyl vapor.

-l.
------------------------------------
My inbox is a sacred shrine, none shall enter that are not worthy.


  #38  
Old October 3rd 07, 12:47 PM posted to rec.arts.sf.science,sci.space.history
Rand Simberg[_1_]
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Default Questions about "The High Frontier"

On Tue, 02 Oct 2007 20:43:27 -0700, in a place far, far away, Johnny1a
made the phosphor on my monitor glow in such
a way as to indicate that:

On Oct 2, 12:51 pm, "Mike Combs"
wrote:
"Pat Flannery" wrote in message

...



It was only after the book that every Tom, Dick, and Harry with a
political or economic axe to grind began looking at space colonies as some
sort of do-it-yourself Utopias where the innate superiority of their
political or economic system would no doubt be shown to all.


It might have been T. A. Heppenheimer who said, "Space colonies are a kind
of political Rorschach test".

But I am sanguine about space habitats as political experimentation
laboratories. If one's society ultimately fails (or just consistently
performs poorly), it would have to be a result of its underlying philosophy.
In a space habitat, one could hardly blame resource depletion, an energy
crisis, population pressures, a crop failure, or inconvenient location.


Doesn't matter, 'cause it won't happen that way.

When you consider the gargantuan capitol investments were talking
about in building such machines, even once we're able to do so, the
chances that they'll be given out to fringe movements or minority
groups to 'experiment' with strains credulity.


I know of no one who has proposed that they be "given out" to anyone.
The "fringe movements" and "minority groups" will raise their own
money to build them.
  #39  
Old October 3rd 07, 12:52 PM posted to rec.arts.sf.science,sci.space.history
Rand Simberg[_1_]
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Default Questions about "The High Frontier"

On Tue, 02 Oct 2007 23:21:20 -0500, in a place far, far away, Pat
Flannery made the phosphor on my monitor glow in
such a way as to indicate that:

But I am sanguine about space habitats as political experimentation
laboratories. If one's society ultimately fails (or just consistently
performs poorly), it would have to be a result of its underlying philosophy.
In a space habitat, one could hardly blame resource depletion, an energy
crisis, population pressures, a crop failure, or inconvenient location.


How about if a neighboring colony blows a hole in yours to let the air
out, then seizes it for their own, as they want to increase their
population?


The hole would be repaired long before the air went out. A hole big
enough to cause a total evacuation of the colony faster than it could
be fixed would be so big as to wreck the colony.

If colonies are affordable for "fringe groups," they're probably
sufficiently cheap that it makes more sense to build another one for
expansion than making war and stealing someone else's. It's not like
rare prime real estate.

A more likely cause of war would be ideological hatred. A Hamas space
colony would still plot ways to destroy the Jew space colony.
  #40  
Old October 3rd 07, 12:54 PM posted to rec.arts.sf.science,sci.space.history
Rand Simberg[_1_]
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Posts: 8,311
Default Questions about "The High Frontier"

On Wed, 3 Oct 2007 06:03:40 +0200 (CEST), in a place far, far away,
Jim Davis made the phosphor on my monitor
glow in such a way as to indicate that:

Jonathan wrote:

I think the upcoming Olympics in Beijing will provide a glimpse
into the priorities of the future. China burns so much coal that
it's air is almost deadly. Dear Mother Nature will give us a
few very calm days in Beijing so the world can watch
the athletes flee the city for their very lives.


Why would just the athletes flee? Why not everyone else? Are only the
athletes' lives in danger? Why aren't people fleeing now?


Don't confuse jonathan with logic.
 




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