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Questions about "The High Frontier"



 
 
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  #301  
Old October 25th 07, 01:54 AM posted to rec.arts.sf.science,sci.space.history
John Schilling
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Default Questions about "The High Frontier"

On Tue, 23 Oct 2007 07:16:47 -0700, Hop David wrote:

John Schilling wrote:


On Fri, 19 Oct 2007 13:10:07 -0500, "Mike Combs"
wrote:


But it's probably going to be a *lot* less expensive if you allow for
the inhabitants to build, provision, and resupply their habitat using
local resources.


And there's every reason in the world to expect an asteroidal settlement to
be doing this.


Except for the critical shortage of local resources that aren't steel or
coal or glass.


And Mars has a much broader range of useful resources


I'm not sure why you would say this. What resources would be available on
the surface of Mars that you couldn't find in a well-selected CC-type
asteroid?


"CC" meaning "Carbonaceous Chondrite" generally?


OK, let's see: How about useful concentrations of Helium, Lithium,
Beryllium, Boron, Nitrogen, Fluorine, Neon, Sodium, Aluminum, Chlorine,
Argon, Potassium, Titanium, Chromium, Manganese, Copper, Zinc, Arsenic,
Bromine, Krypton, Strontium, Zirconium, Niobium, Molybdenum, Silver, Tin,
Antimony, Iodine, Xenon, Barium, Hafnium, Tantalum, Tungsten, Gold,
Mercury, Lead, Bismuth, Thorium, and Uranium.


While CCs may be poor in some those materials, there are other asteroids
that aren't.


What sort of asteroid do you imagine has useful concentrations of, say,
Boron?

Zinc?

Tin?

Lead?


I acknowledge that one asteroid containing all these resources would be
rare.


An asteroid containing *any one* of those resources is going to be rare
indeed. I didn't just pull the list out of my ass, you know.


On the other hand, there's no superhighways, oceans or rivers that can
be used for transportation on Mars. Transportation will be a substantial
barrier to self sufficiency on Mars as well as among the NEOs.


Transportation by dirt road, is many orders of magnitude cheaper than
space transportation.


Mars definitely has some of those in abundance , and almost certainly has
useful ores of the rest on account of having experienced the same geologic
processes that produced such ores on Earth.


I seem to recall Peter Tillman saying uranium ore was concentrated via
biological processes.


Only a minority of uranium ores, and AIUI it's a minority opinion even
there. Mostly, uranium ores come from abiotic hydrothermal processes,
followed by selective precipitation.


There's certainly some ore concentrating processes on Mars, but I don't
regard it as a given Mars would have all the same ores earth does.


I didn't include any of the minerals for which biologic mechanisms are
necessary. And the purely physiochemical stuff, Mars really does seem
to have had the full range of Earth-style geologic activity. Rather
less active at present, of course, but then there's been nothing going
on to deplete the old ore bodies either.


Carbonaceous chondrites, based on the meteoric evidence, do not.


Meteoric evidence is biased. Some meteorites are much more perishable
than others. If they're not discovered within hours or days of impact,
they're gone. More durable objects are more likely to reach the earth's
surface and become meteorites.


You're talking about iceballs, I assume. Those don't come from NEOs,
except in the "occasionally passes right close to Earth at an ungodly
high relative velocity" definition of NEO. Which is of interest to the
impact-hazards community, but not so much for asteroid mining.

NEOs in the sense of being easily accessible for round-trip travel
from Earth, by definition spend most of their time in a climate too
warm for ice to endure.


Some carbonaceous chondrites may be homogenous aggregates that haven't
experienced any ore concentrating processes. But this isn't the case for
all asteroids. Metallic asteroids are believed to come from the interior
of large asteroids that were massive enough to have differentiated layers.


Which gives you concentrations of iron, nickel, cobalt, and (for a
perverse but economically relevant definition of "concentration"),
the platinum-group elements.

That's it. A really nice grade of stainless steel, a bit of platinum,
and nothing more. Metallic asteroids will make their owners "rich"
in the way Midas was rich.


I also believe there can be ore concentrating processes going on in
objects that outgas when they're closer to the sun.


Such as?

OK, the outgassing of volatiles is by definition a "concentrating process"
for non-volatiles, but there's nothing to concentrate one non-volatile
over another. And the non-volatiles are almost entirely oxides of
silicon, calcium, and magnesium. So there's your glass, and your
magnesium.


Asteroids, are where you get steel and coal and glass, and maybe magnesium
and platinum for the export markets, and that's really about it.


I believe water, ammonia and other volatiles not at the bottom of a
steep gravity well and not far from the earth would be valuable.


Yes, but you're not going to find ammonia in a near-earth asteroid.
Not likely you'll be finding much of any nitrogenous compounds there.

Water, you can get, though only bound up in a mass of carbonaceous
non-volatiles that bears a strong resemblence to coal. And you've
got to be pretty desperate to try and squeeze water from a lump of
coal. But it's at least within the bounds of reason and plausibilty.


On http://clowder.net/hop/railroad/asteroidresources.html I give a list
of reasons (with some web cites) why I believe volatile rich NEOs exist.


I only see reasons to believe volatile-rich asteroids exist. Main belt
asteroids, out where the equilibrium temperature is a nice 200K or less.
If you've got anything for volatile-rich NEOs, I couldn't find it.

And even then, that only gives you nitrogen and somewhat more accessible
hydrogen. That still leaves most of the periodic table that you aren't
going to be squeezing out of an asteroid without invoking elfin magic
as a refining technology.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
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  #302  
Old October 25th 07, 04:14 AM posted to rec.arts.sf.science,sci.space.history
Jim Davis
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Posts: 420
Default Questions about "The High Frontier"

Mike Combs wrote:

This big difference is that a person on an oil rig can pop back
and forth between it and land much more quickly and
inexpensively than a person working in HEO can pop back and
forth to Earth.


Coincidentally, this is one of the main reasons why we have oil
rigs but not SSP in HEO. Any SSP and/or space colonization scheme
presupposes enormous improvements in transportation costs.

But I think
part of my point was that a company might have a perfectly
selfish reason for wanting to provide their workers with decent
places to live


But your solution is to provide them with a *less* decent place to
live.

(namely, a desire to not have to train and
educate new recruits every two years because nobody wants to
stay with the company any longer than that).


?????

Why do you assume that nobody would want to stay with a company
that pays high wages for longer than two years?

Yeah, I'm aware that I'm arguing events will go in the direction
of my fondest dreams. So caution is called for.


Indeed.

Jim Davis





  #303  
Old October 25th 07, 04:48 AM posted to rec.arts.sf.science,sci.space.history
Michael Turner
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Default Questions about "The High Frontier"

On Oct 25, 8:10 am, Hop David wrote:
Quadibloc wrote:
On Oct 23, 12:02 pm, "Mike Combs"
wrote:


There seems to be an assumption that overland travel on Mars has got to be
easier than moving between asteroids because the latter is space travel and
the former isn't, and as everybody knows, space travel is difficult,
dangerous, and hideously expensive. I think this notion overlooks two
points:


1. Overland travel on Mars, unlike same on Earth, will have pressurization
and other life-support requirements little different from space travel.


2. Our notions of space travel are influenced by our most common experience
of it, which is to say, travel from the surface of the Earth into orbit.
Such travel requires large amounts of thrust (greatly in excess of vehicle
weight in 1-G) quickly achieved, and an aerodynamic shape. None of these
will be requirements for systems traveling from one asteroid to another.


These are legitimate points. If one is _in_ space, one doesn't need an
awful lot of thrust to go places.


However, while a Mars buggy needs to be pressurized, a voyage from one
asteroid to another, if it is to have modest fuel requirements, will
take a while. Trips between the Kuiper Belt for biomass and the
Asteroid Belt for metals will take many years.


Trips to the Kuiper belt for biomass are unnecessary, in my opinion.http://clowder.net/hop/railroad/asteroidresources.html

Nor are trips to the asteroid belt. I suspect both metallic asteroids
and asteroids with ice interiors exist among the NEOs.



So, while you are right that the commonplace view based on past
experience of an Apollo moon mission versus a drive to the country in
one's car exaggerates the situation, Mars is a single body that has
both metals and carbon, hydrogen, oxygen, and nitrogen available. So I
think it is still favored for lower start-up costs despite the fact
that the disparity can be exaggerated.


And what would the return on investment for martian start up costs be? I
can imagine profitable exports from the Moon, Phobos, Deimos or NEOs to
near earth space. These may be unlikely but profitable Martian exports
are far more unlikely.

Hop- Hide quoted text -

- Show quoted text -


Yes, this reminds me of the premise for a novel I outlined for a
former member of the Mars Society: in some decade late in this
century, there is a space-faring society including tourism operations
in LEO, colonies on the moon and mining outposts on asteroids and the
Martian moons, with a tiny fringe activist group scattered among them
that never seems to get any political traction or private financing
for its agenda of colonizing Mars.

This activist group's last, best hope in the opening pages of this
never-to-be-written SF non-classic: a passel of lawsuits wending their
way through appeals courts in various jurisdictions on and off Earth,
based on stretching the letter and spirit of deep-space claims law to
make Mars their property. In one suit they seek reparations from past
and present users of the Martian atmosphere (for aerobraking) and the
Martian gravity well (for momentum exchange), for having provided
"propulsion services". In another, they want to impose fines for
littering, since aerobrakes inevitably deposit some debris in the
Martian atmosphere and in orbit. They are also suing for rent in
arears, from the corporations mining Phobos and Deimos. In support of
these suits, they cite a passage granting the right to exploit the
main bodies and any satellites of properly claimed asteroids, and the
considered opinion of an obscure member of the International
Astronomical Union (Luna Branch) that all objects orbiting the sun
should be called "asteroids" (a guy who -- surprise -- happens to be a
member of their society.) And what about the longstanding legal
requirement that a living human being be present on the surface of an
asteroid to establish a claim? Decades before, much to the
consternation of exobiologists *still* concerned about forward
contamination of Mars, this group carried out a mission to drop a
package containing a frozen fertilized human ovum into a polar region
of Mars, with most of the money coming from a pro-life PAC with whom
they otherwise have rather testy relations (politics making, as
always, for strange bedfellows.) The little guy's name is Bob,
though there's a splinter faction that prefers the name "Mike". Bob's
shelf-life is soon to expire, unfortunately, assuming he was ever
viable at all after the cosmic ray exposure suffered on the trip to
Mars in an undershielded vehicle thrown together on the cheap.

In that notional future, this pro-Mars-colonization group is,
naturally enough, called The Mars Society. Because that's the kind of
mean, sarcastic guy I am. ;-)

-michael turner

  #304  
Old October 25th 07, 05:41 AM posted to rec.arts.sf.science,sci.space.history
Hop David
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Default Questions about "The High Frontier"

Pat Flannery wrote:



Hop David wrote:


There were no Carracks in the time of Ferdinand III. And the resources
of the mid-Atlantic would not have justified the development and
building of Carracks.



As to carracks, there were indeed carracks around in the 15th century...


Ferdinand III of Castille was not alive in the 15th century.
http://en.wikipedia.org/wiki/Ferdinand_III_of_Castile

in fact, I hate to do this... but the Santa Maria was a carrack:
http://en.wikipedia.org/wiki/Carrack
http://en.wikipedia.org/wiki/Santa_M...ADa_%28ship%29


And I could point out ducks are birds. But that would be irrelevant and
stating the obvious.

Please reread this subthread more carefully.

Hop
  #305  
Old October 25th 07, 05:45 AM posted to rec.arts.sf.science,sci.space.history
Pat Flannery
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Posts: 18,466
Default Questions about "The High Frontier"



Hop David wrote:

Trips to the Kuiper belt for biomass are unnecessary, in my opinion.
http://clowder.net/hop/railroad/asteroidresources.html


Thank God for small favors; I'd like to see what the energy required to
get get something from the Kuiper belt down into Earth orbit would be like.


Nor are trips to the asteroid belt. I suspect both metallic asteroids
and asteroids with ice interiors exist among the NEOs.


Metals probably, at least for some.
Ice? Depends how close to the Sun they get, because your concept
basically describes a short period comet, with the volatile boil-off
that implies.

Pat

  #306  
Old October 25th 07, 06:08 AM posted to rec.arts.sf.science,sci.space.history
Hop David
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Default Questions about "The High Frontier"

John Schilling wrote:

On Tue, 23 Oct 2007 08:26:08 -0700, Hop David wrote:


Michael Turner wrote:



I don't think hysteria is the right word. Large payloads would be harder
to control and a tiny error could change aerobraking to lithobraking. I
would call it "Deep Impact sensible fear". Again, I advocate payload
mass ceilings well below Tunguska size.



I'm still curious whether there might be a way to increase payload
mass and reduce terrestrial hazards by delivering asteroid-derived
payloads to Earth orbit in the form of large spherical shells of
material. As I've probably mentioned in this forum before, I was once
asked to look at an RFP for "demisable tanks" -- i.e., satellite fuel
tanks guaranteed to burn up on reentry. That inquiry went nowhere,
AFAIK. Which underscores a point: maybe you don't need ablative
shielding or heat-soaking tiles to bring stuff down intact. After
all, LEO satellite fuel tanks have been found in desert regions with
little more than scorch marks and dents from hitting the ground (at a
relatively low terminal velocity, obviously.) Maybe that's a bug for
satellite fuel tanks, but it's arguably a feature if you're interested
in aerobraking or aerocapture of resources delivered from cislunar or
interplanetary space.




Now let's say you want to deliver a lot of asteroid-mined metal to an
L-point, using aerobraking in the Earth's atmosphere. Blow the metal
up into a big, relatively thin-walled sphere. Maybe store some
asteroid-derived volatiles inside, which would coat the interior as
they freeze down to the point where you get into equilibrium with
sublimation losses.



Asteroid mined metal would come from a metallic asteroid which is
unlikely to have volatiles.



Actually, the stony chondrites are typically 10% metal or so, and metal
in a much more easily recovered form - the stuff can be magnetically
seperated from finely crushed rock, and there's reason to believe that
lots of stony chondrites have pre-crushed surfaces. If not, well, we
know how to make rock-crushers.


Thank you for the correction.


Metal asteroids, seem to be solid metal. Solid nickel steel, rather
like the stuff battleships used to be made out of. This poses certain
obvious problems for any wannabe asteroid-miner...


Do you believe cutting the asteroid into smaller more manageable chunks
is a insurmountable problem?

Hop

  #307  
Old October 25th 07, 06:12 AM posted to rec.arts.sf.science,sci.space.history
Pat Flannery
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Default Questions about "The High Frontier"



John Schilling wrote:

What sort of asteroid were you imagining had useful concentrations of
Nitrogen, again?


That's not a asteroid, that's a comet with methane ice on it.
And the only ones with _that_ still intact are going to go through the
inner solar system like a bat out of proverbial Hell, and be very
difficult to move into Earth orbit.

And the Moon seems scarcely better, though it's at least different and
it's big enough that there's still room for surprises. Mostly, though,
both the Moon and the Asteroids are very boring, geologically speaking,
each rich in about half a dozen or so sorts of useful stuff and that's
about it.


Particularly the Moon, which was originally formed off of the blasted
off outer lithosphere of the proto-Earth, only high in the lighter
elements and metals.

For the full range of minerals you need to support a civilization, you
really want something with a more interesting geology.


Though if you could somehow figure out a way to get a couple of cubic
miles of nickel-iron into HEO, your stainless steel requirements for
space colony construction would be taken care of for quite some time.
You're going to need something like the biggest Orion nuclear pulse
engine you ever laid eyes on to pull it off though.
The pusher plate would be huge, and have H-bombs detonating behind it. :-)

Pat
  #308  
Old October 25th 07, 06:43 AM posted to rec.arts.sf.science,sci.space.history
Johnny1a
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Posts: 25
Default Questions about "The High Frontier"

On Oct 24, 4:29 pm, Pat Flannery wrote:

As I pointed out before, you could start building cities in Antarctica
in conditions more pleasant than Mars; you can breath the air, and water
is already proven to be plentiful. There's bound to be minerals of one
sort or another, transportation to and from the place is fairly quick
and low cost, and assuming you like a diet high in meat rather than
vegetables, the seas surrounding its coast will provide it in abundance.
But you don't see cities springing up all over it or in the Australian
outback (even Brazil pretty much admitted Brasilia was a flop of an
idea), and that doesn't bode any too well for places that are even more
uncomfortable in regards to climate. Say ones lacking breathable air and
getting sprayed with the solar wind.

Pat


This isn't really valid, except in the very shortest term. It's
simply impossible to make meaningful predictions about changing
economic, religious, and social impulses over the long term, and any
of those can transform 'utterly impractical' to 'let's do it'.

  #309  
Old October 25th 07, 06:51 AM posted to rec.arts.sf.science,sci.space.history
Johnny1a
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Default Questions about "The High Frontier"

On Oct 24, 12:25 pm, "Mike Combs"
wrote:
"Jim Davis" wrote in message

. 96.26...



Mike, you're a good guy and everything, but the above is a textbook
example of thinking with your heart instead of your head. In any
other context except space (you yourself bring up oil rigs) you
would quickly recognize the absurdities. But since this is space
we're talking about...well, things are different in space, right?


This big difference is that a person on an oil rig can pop back and forth
between it and land much more quickly and inexpensively than a person
working in HEO can pop back and forth to Earth.

Yeah, I'm aware that I'm arguing events will go in the direction of my
fondest dreams. So caution is called for. But I think part of my point was
that a company might have a perfectly selfish reason for wanting to provide
their workers with decent places to live (namely, a desire to not have to
train and educate new recruits every two years because nobody wants to stay
with the company any longer than that).


And you could be right in principle, eventually.

The trouble is that O'Neill Habs are not just 'decent places to live'
in the usual sense, there's a huge gap in options between 'bare-bones
construction shack' and 'O'Neill Hab'. You have to go a _long_ way to
make the O'Neill justifiable on any terms other than 'for its own
sake'.

I'm actually more-or-less on your side of the debate...on a longer-
term time scale. I _do_ think humans are going to spread out into
space, probably eventually on both the planets and in artificial
environments in space. I doubt very seriously if any O'Neill Habs _as
such_ will ever be built, any more than we ever built the Jule Verne
cannon to send men to the Moon, or built da Vinci's flying machines to
make air travel workable.

But it's not going to happen in accordance with the economic/social
motives O'Neill posited.

  #310  
Old October 25th 07, 06:54 AM posted to rec.arts.sf.science,sci.space.history
Johnny1a
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Posts: 25
Default Questions about "The High Frontier"

On Oct 24, 3:50 pm, Pat Flannery wrote:
Johnny1a wrote:
Population growth rates aren't controlled by the availability of birth
control. In fact, nobody knows what determines population growth and
decrease rates once the basic necessities of life are covered, they
seem to follow a logic of their own.


One problem they had with birth control in the third world (besides
religious taboos, and macho issues) was that a lot of the people
couldn't understand that the principle the condom worked on was (there's
actually one culture I read about somewhere out there that recognizes no
connection between sex and pregnancy. Women get pregnant when the gods
deem they should get pregnant, and if a husband is away from his wife
for a year and comes back to find her nursing a baby...well, that was
just her time to get pregnant, that's all). :-)
In one village in Africa, a family planning nurse demonstrated how the
condom was to be used by putting it over the end of a broom handle; on
her next visit, she noted that the villagers were now convinced that the
birth rate was going to drop as every broom handle in the village now
had a condom on it.
Considering the number of unwanted pregnancies that occur here in the
U.S. even nowadays, I suspect that easily available, reliable and low
priced birth control worldwide would lead to a major decline in
birthrate to below replacement levels, especially in non-sustenance
agrarian societies - as that is one of the few areas where a large
family is a asset, as many children means many workers to till the land.
Even here in North Dakota average farm family size is far lower since
the advent of advanced farm machinery, as back in the 1930's farm
families with ten or more children were not uncommon. I even knew a farm
girl born in the late 1950's who had eleven brothers and sisters.

Pat


The trouble with this is that history doesn't support it. There have
been periods in history when population growth levelled off or even
went negative, then surged again. The reasons don't seem to be
primarily economically rooted.

In the late Roman Empire, for ex, there were concerns with falling
populations and low birth rates. It wasn't caused by the ready
availability of reliable birth control.

 




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