All,

I just finished reading an amazing book Mining the Sky by John S. Lewis. He presents some mind-stretching scenarios for us to ponder. Key points:

1) The resources in the asteroid belts are vast

2) Fusion energy is essential for stellar space travel and Uranus has plenty of He3 and a low gravity well to make mining the most practical of the gas giants. He3 is ideal for fusion since very little output is in the form of neutrons hence very hot plasma is the principle outlet which would make an ideal rocket engine as well as generator of electricity if run through a magnetic coil of wire.

3) Space colonies can support many billions of people.

Highly recommended reading.

My spin, key issue, is that we must achieve reduced cost to achieve LEO because without it, space colonies will remain in the distant future.

A site I am intrigued with discusses space tethers which I think has possibilities: http://www.tethers.com/ If anyone has any knowledge, good or bad, about space tethers, please let me know.

Cheers,

Tom Tucker

I just finished reading an amazing book Mining the Sky by John S. Lewis. He presents some mind-stretching scenarios for us to ponder. Key points:

1) The resources in the asteroid belts are vast

2) Fusion energy is essential for stellar space travel and Uranus has plenty of He3 and a low gravity well to make mining the most practical of the gas giants. He3 is ideal for fusion since very little output is in the form of neutrons hence very hot plasma is the principle outlet which would make an ideal rocket engine as well as generator of electricity if run through a magnetic coil of wire.

3) Space colonies can support many billions of people.

Highly recommended reading.

My spin, key issue, is that we must achieve reduced cost to achieve LEO because without it, space colonies will remain in the distant future.

A site I am intrigued with discusses space tethers which I think has possibilities:
http://www.tethers.com/
If anyone has any knowledge, good or bad, about space tethers, please let me know.

Cheers,

Tom Tucker

--- "Tom Tucker: (Olympia)"
> All,
>
> I just finished reading an amazing book Mining the
> Sky by John S. Lewis. He presents some
> mind-stretching scenarios for us to ponder. Key
> points:
>
> 1) The resources in the asteroid belts are vast

MW: Way more than a 300 billion dollars of wealth for
every human on Earth. Such an amount of wealth would
make Bill Gates look poor. And of course this does not
include the amount of natural resources that could be
mined on the surfaces of the moon, Mars, Mercury, and
Callisto.
>
> Tom Tucker: 2) Fusion energy is essential for
stellar space
> travel and Uranus has plenty of He3 and a low
> gravity well to make mining the most practical of
> the gas giants. He3 is ideal for fusion since very
> little output is in the form of neutrons hence very
> hot plasma is the principle outlet which would make
> an ideal rocket engine as well as generator of
> electricity if run through a magnetic coil of wire.
>
> 3) Space colonies can support many billions of
> people.

MW: Lewis estimated that possibly 10 quadrillion
people could be accommodated which was similar to
O'neills estimates. But I would doubt if we ever need
to house more than a trillion people on space islands
in our solar system.
>
>Tom Tucker: Highly recommended reading.
>
MW: I agree

> Tom Tucker: My spin, key issue, is that we must
achieve reduced
> cost to achieve LEO because without it, space
> colonies will remain in the distant future.
>
MW: We will never be able to afford to manufacture
space islands large enough to attract most people to
live in them premanently until we industrialize the
moon and Mars, and begin to exploit the asteriods. And
before we can do that, we have to build a reusable
heavy lift vehicle like NASA wanted to build back in
the 1970's and 80's and a reusable aerospace plane
that can take off from any airport. Such reusable
Earth to orbit vehicles shouldn't cost more than 5
billion a year to build over a 7 to 10 year period,
IMO, which would raise the NASA budget from about 14
billion annually to about 19 billion dollars annually.
Far better than waisting money on another Star Wars
program, IMO.

Marcel F. Williams
12/10/00

Marcel,

IMO, the earth's gravity well is too deep for a single plane or stage to orbit (i.e. STO) vehicle to work unless we somehow discover anti-gravity :-). This is why I am examining the tether approach. You see, what is the tether could build-up speed in LEO using nuclear or solar power, and then dip down to pick-up the payload from a Boeing space plane at say 100KM? Why go all the way to orbit when something in orbit could work as a team and meet you half-way, so to speak? Lets think outside of the box and not be tied to the notion that we have to have a single vehicle that can independently go from earth to LEO un-assisted.
For further background on this question, I recommend Dr. Zubrin's book Entering Space, chapter 3 "The New Space Race" where he review various space plane options and current projects. The bottom line is that STO will work on Mars and the Moon, but not on earth; too much gravity.

Zubrin also points out that the major rocket manufacturers have absolutely no incentive to reduce the cost to LEO since they feel that they would be cutting their own financial throat. Independent efforts are indicated and, IMO, the winner may not be flown from US soil at the rate we are going now.

Cheers,

Tom
From: Marcel Williams
To: spacesettlers@egroups.com
Sent: Sunday, December 10, 2000 7:32 PM
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO

--- "Tom Tucker: (Olympia)"
wrote:
> All,
>
> I just finished reading an amazing book Mining the
> Sky by John S. Lewis. He presents some
> mind-stretching scenarios for us to ponder. Key
> points:
>
> 1) The resources in the asteroid belts are vast

MW: Way more than a 300 billion dollars of wealth for
every human on Earth. Such an amount of wealth would
make Bill Gates look poor. And of course this does not
include the amount of natural resources that could be
mined on the surfaces of the moon, Mars, Mercury, and
Callisto.
>
> Tom Tucker: 2) Fusion energy is essential for
stellar space
> travel and Uranus has plenty of He3 and a low
> gravity well to make mining the most practical of
> the gas giants. He3 is ideal for fusion since very
> little output is in the form of neutrons hence very
> hot plasma is the principle outlet which would make
> an ideal rocket engine as well as generator of
> electricity if run through a magnetic coil of wire.
>
> 3) Space colonies can support many billions of
> people.

MW: Lewis estimated that possibly 10 quadrillion
people could be accommodated which was similar to
O'neills estimates. But I would doubt if we ever need
to house more than a trillion people on space islands
in our solar system.
>
>Tom Tucker: Highly recommended reading.
>
MW: I agree

> Tom Tucker: My spin, key issue, is that we must
achieve reduced
> cost to achieve LEO because without it, space
> colonies will remain in the distant future.
>
MW: We will never be able to afford to manufacture
space islands large enough to attract most people to
live in them premanently until we industrialize the
moon and Mars, and begin to exploit the asteriods. And
before we can do that, we have to build a reusable
heavy lift vehicle like NASA wanted to build back in
the 1970's and 80's and a reusable aerospace plane
that can take off from any airport. Such reusable
Earth to orbit vehicles shouldn't cost more than 5
billion a year to build over a 7 to 10 year period,
IMO, which would raise the NASA budget from about 14
billion annually to about 19 billion dollars annually.
Far better than waisting money on another Star Wars
program, IMO.

Marcel F. Williams
12/10/00

IMO, the earth's gravity well is too deep for a single plane or stage to orbit (i.e. STO) vehicle to work unless we somehow discover anti-gravity :-). This is why I am examining the tether approach. You see, what is the tether could build-up speed in LEO using nuclear or solar power, and then dip down to pick-up the payload from a Boeing space plane at say 100KM? Why go all the way to orbit when something in orbit could work as a team and meet you half-way, so to speak? Lets think outside of the box and not be tied to the notion that we have to have a single vehicle that can independently go from earth to LEO un-assisted.
For further background on this question, I recommend Dr. Zubrin's book Entering Space, chapter 3 "The New Space Race" where he review various space plane options and current projects. The bottom line is that STO will work on Mars and the Moon, but not on earth; too much gravity.

Zubrin also points out that the major rocket manufacturers have absolutely no incentive to reduce the cost to LEO since they feel that they would be cutting their own financial throat. Independent efforts are indicated and, IMO, the winner may not be flown from US soil at the rate we are going now.

Cheers,

Tom

From:
Marcel Williams
To:
spacesettlers@egroups.com
Sent:
Sunday, December 10, 2000 7:32 PM
Subject:
Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO
--- "Tom Tucker: (Olympia)" <
tntucker@connectcorp.net
>
> All,
>
> I just finished reading an amazing book Mining the
> Sky by John S. Lewis. He presents some
> mind-stretching scenarios for us to ponder. Key
> points:
>
> 1) The resources in the asteroid belts are vast
MW: Way more than a 300 billion dollars of wealth for
every human on Earth. Such an amount of wealth would
make Bill Gates look poor. And of course this does not
include the amount of natural resources that could be
mined on the surfaces of the moon, Mars, Mercury, and
Callisto.
>
> Tom Tucker: 2) Fusion energy is essential for
stellar space
> travel and Uranus has plenty of He3 and a low
> gravity well to make mining the most practical of
> the gas giants. He3 is ideal for fusion since very
> little output is in the form of neutrons hence very
> hot plasma is the principle outlet which would make
> an ideal rocket engine as well as generator of
> electricity if run through a magnetic coil of wire.
>
> 3) Space colonies can support many billions of
> people.
MW: Lewis estimated that possibly 10 quadrillion
people could be accommodated which was similar to
O'neills estimates. But I would doubt if we ever need
to house more than a trillion people on space islands
in our solar system.
>
Tom Tucker: Highly recommended reading.
>
MW: I agree
> Tom Tucker: My spin, key issue, is that we must
achieve reduced
> cost to achieve LEO because without it, space
> colonies will remain in the distant future.
>
MW: We will never be able to afford to manufacture
space islands large enough to attract most people to
live in them premanently until we industrialize the
moon and Mars, and begin to exploit the asteriods. And
before we can do that, we have to build a reusable
heavy lift vehicle like NASA wanted to build back in
the 1970's and 80's and a reusable aerospace plane
that can take off from any airport. Such reusable
Earth to orbit vehicles shouldn't cost more than 5
billion a year to build over a 7 to 10 year period,
IMO, which would raise the NASA budget from about 14
billion annually to about 19 billion dollars annually.
Far better than waisting money on another Star Wars
program, IMO.
Marcel F. Williams
12/10/00

From: Tom Tucker (Olympia) [mailto:tntucker@...]

I just finished reading an amazing book Mining the Sky by John S. Lewis. He
presents some mind-stretching scenarios for us to ponder.

Your reference to Lewis reminded me of something that I need to announce to
the list. The 3rd edition of "The High Frontier" has recently been
released. This latest edition includes new material written by John Lewis,
Peter Glaser, Rick Tumlinson, George Friedman, and others. There's an
introduction by Roger O'Neill, and a preface by Freeman Dyson.

Go to http://www.ssi.org/high-frontier.html
for more info.

Regards,
Mike Combs

From:
Tom Tucker (Olympia) [mailto:tntucker@...]

I just finished reading an amazing book Mining the Sky by John S. Lewis. He presents some mind-stretching scenarios for us to ponder.

Your reference to Lewis reminded me of something that I need to announce to the list. The 3rd edition of "The High Frontier" has recently been released. This latest edition includes new material written by John Lewis, Peter Glaser, Rick Tumlinson, George Friedman, and others. There's an introduction by Roger O'Neill, and a preface by Freeman Dyson.

Go to
http://www.ssi.org/high-frontier.html
for more info.

Regards,
Mike Combs

From: "Tom Tucker (Olympia)"
To:
Sent: Segunda-feira, 11 de Dezembro de 2000 02:09
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO

[snikt]
IMO, the earth's gravity well is too deep for a single plane or stage to
orbit (i.e. STO) vehicle to work unless we somehow discover anti-gravity
:-). This is why I am examining the tether approach. You see, what is the
tether could build-up speed in LEO using nuclear or solar power, and then
dip down to pick-up the payload from a Boeing space plane at say 100KM? Why
go all the way to orbit when something in orbit could work as a team and
meet you half-way, so to speak? Lets think outside of the box and not be
tied to the notion that we have to have a single vehicle that can
independently go from earth to LEO un-assisted.

I agree that space tethers would be the cheapest way to go into orbit (after
a huge initial investment, of course). However, I'm not that skeptical about
a STO vehicle. As Darren said in another message, the LightCraft concept -
where the vehicle would not have to use any propellant during part of the
ascent and would have to use much less propellant from that point on - seems
very promising; moreover, theoretical calculations for the LightCraft are
sound, IMHO. (See http://www.sciam.com/1999/0299issue/0299beardsleybox4.html
.)

The great appeal of STOs is that they would need no startup investment in
space in order to reach space in a cheap way. Space tethers as I know them
would require gargantuan tasks in space, far beyond our current technology,
like putting a carbonaceous asteroid with a few cubic kilometers into
geosynchronic orbit and then building a cable made of carbon nanotubes
(nowadays a material far more expensive than gold) till touch Earth. A STO,
on the other hand, would be made on Earth and would be several orders of
magnitude cheaper, and they so they are the next logical research target
until all possibilities are exhausted.

>From your text above, I think that the site that you linked in your other
message proposes other kinds of space tethers; unfortunately, the site was
down when I tried to access it. Would you please explain briefly the
principles involved?

Zubrin also points out that the major rocket manufacturers have absolutely
no incentive to reduce the cost to LEO since they feel that they would be
cutting their own financial throat. Independent efforts are indicated and,
IMO, the winner may not be flown from US soil at the rate we are going now.

No wonder that the LightCraft project is under USAF, if I remeber
correctly...

Cheers,

Cheers,

Tom

Lucio

--- "Combs, Mike" wrote:
> From: Tom Tucker (Olympia)
> [mailto:tntucker@...]
>
> I just finished reading an amazing book Mining the
> Sky by John S. Lewis. He
> presents some mind-stretching scenarios for us to
> ponder.
>
> Your reference to Lewis reminded me of something
> that I need to announce to
> the list. The 3rd edition of "The High Frontier"
> has recently been
> released. This latest edition includes new material
> written by John Lewis,
> Peter Glaser, Rick Tumlinson, George Friedman, and
> others. There's an
> introduction by Roger O'Neill, and a preface by
> Freeman Dyson.
>
> Go to http://www.ssi.org/high-frontier.html
> for more
> info.
>
> Regards,
> Mike Combs

MW: The High Frontier was probably one of the most
important books about space in the 20th century, IMO.

Marcel F. Williams
12/11/00

From: Dr. Omni
To: spacesettlers@egroups.com
Sent: Monday, December 11, 2000 10:09 AM
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO

From: "Tom Tucker (Olympia)"
To:
Sent: Segunda-feira, 11 de Dezembro de 2000 02:09
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO

[snikt]
IMO, the earth's gravity well is too deep for a single plane or stage to
orbit (i.e. STO) vehicle to work unless we somehow discover anti-gravity
:-). This is why I am examining the tether approach. You see, what is the
tether could build-up speed in LEO using nuclear or solar power, and then
dip down to pick-up the payload from a Boeing space plane at say 100KM? Why
go all the way to orbit when something in orbit could work as a team and
meet you half-way, so to speak? Lets think outside of the box and not be
tied to the notion that we have to have a single vehicle that can
independently go from earth to LEO un-assisted.

I agree that space tethers would be the cheapest way to go into orbit (after
a huge initial investment, of course). However, I'm not that skeptical about
a STO vehicle. As Darren said in another message, the LightCraft concept -
where the vehicle would not have to use any propellant during part of the
ascent and would have to use much less propellant from that point on - seems
very promising; moreover, theoretical calculations for the LightCraft are
sound, IMHO. (See http://www.sciam.com/1999/0299issue/0299beardsleybox4.html
.)
Tom - I'll have to check it out.

The great appeal of STOs is that they would need no startup investment in
space in order to reach space in a cheap way. Space tethers as I know them
would require gargantuan tasks in space, far beyond our current technology,
like putting a carbonaceous asteroid with a few cubic kilometers into
geosynchronic orbit and then building a cable made of carbon nanotubes
(nowadays a material far more expensive than gold) till touch Earth.

Tom - I haven't seen this particular proposal. It is true that a significant investment would be required, but a two hundred weight, partially made-up of spent boosters, would suffice, and conventioal materials are suitible for the tether per the analysis I've seen. Either nuclear or solar power can be used to charge, or replace the orbital velocity lost when picking up a payload. Nuclear could recharge in a couple of weeks and solar around 9 months depending upon final configuration.
I think it is time for fresh thinking in this arena. Perhaps we are trying to do the equivalent of flying to NY and back without realizing the need for a major airport at our destination? A single or even a dozen flights would be very expensive since we would have to take all of our fuel with us and landing/take-off would be difficult at best. The massive investment to build an international airport is not obvious to early air travelers, just as the need to build/invest in space facilities to reduce the costs of LEO are not obvious to us today. The key question is what would be the payback period and how long would the facility last in orbit?
How much would it be worth to the space, tourist industry if costs to LEO and to orbit near the moon were brought down to around $50/lb? Would an investment of 100 billion be cost-effective? What about 200 billion? The key is projecting tourist demands since they will be the initial paying customers.

A STO,
on the other hand, would be made on Earth and would be several orders of
magnitude cheaper, and they so they are the next logical research target
until all possibilities are exhausted.

From your text above, I think that the site that you linked in your other
message proposes other kinds of space tethers; unfortunately, the site was
down when I tried to access it. Would you please explain briefly the
principles involved?

Tom - Pictures are really needed to illustrate, but I will give a high-level overview. The tether rotates much like a croquette mallet if tossed into the air. The counter-weight is about 100 to 200 tons and includes a power source to boost orbit using current interaction with the earth's magnetic field. The end of the tether has a grapeling device that dips down into the atmosphere just when a space plane is at the peak of it's "pop up" and it grabs the payload and pulls it into orbit. See the tether web site for papers for details. There are over 150 of them, and NASA is funding some of the research.
Drawbacks:
1) orbital velocity may not be provided by the tether.
2) rendezvous between tether and payload may be dicy at best,
3) There may be a better way than using a tether.

Regards,

Tom Tucker

Zubrin also points out that the major rocket manufacturers have absolutely
no incentive to reduce the cost to LEO since they feel that they would be
cutting their own financial throat. Independent efforts are indicated and,
IMO, the winner may not be flown from US soil at the rate we are going now.

No wonder that the LightCraft project is under USAF, if I remeber
correctly...

Cheers,

Cheers,

Tom

Lucio

From:
Dr. Omni
To:
spacesettlers@egroups.com
Sent:
Monday, December 11, 2000 10:09 AM
Subject:
Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO
From: "Tom Tucker (Olympia)" <
tntucker@...
>
To: <
spacesettlers@egroups.com
>
Sent: Segunda-feira, 11 de Dezembro de 2000 02:09
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO
[snikt]
IMO, the earth's gravity well is too deep for a single plane or stage to
orbit (i.e. STO) vehicle to work unless we somehow discover anti-gravity
:-). This is why I am examining the tether approach. You see, what is the
tether could build-up speed in LEO using nuclear or solar power, and then
dip down to pick-up the payload from a Boeing space plane at say 100KM? Why
go all the way to orbit when something in orbit could work as a team and
meet you half-way, so to speak? Lets think outside of the box and not be
tied to the notion that we have to have a single vehicle that can
independently go from earth to LEO un-assisted.
I agree that space tethers would be the cheapest way to go into orbit (after
a huge initial investment, of course). However, I'm not that skeptical about
a STO vehicle. As Darren said in another message, the LightCraft concept -
where the vehicle would not have to use any propellant during part of the
ascent and would have to use much less propellant from that point on - seems
very promising; moreover, theoretical calculations for the LightCraft are
sound, IMHO. (See
http://www.sciam.com/1999/0299issue/0299beardsleybox4.html
.)
Tom - I'll have to check it out.
The great appeal of STOs is that they would need no startup investment in
space in order to reach space in a cheap way. Space tethers as I know them
would require gargantuan tasks in space, far beyond our current technology,
like putting a carbonaceous asteroid with a few cubic kilometers into
geosynchronic orbit and then building a cable made of carbon nanotubes
(nowadays a material far more expensive than gold) till touch Earth.

Tom - I haven't seen this particular proposal. It is true that a significant investment would be required, but a two hundred weight, partially made-up of spent boosters, would suffice, and conventioal materials are suitible for the tether per the analysis I've seen. Either nuclear or solar power can be used to charge, or replace the orbital velocity lost when picking up a payload. Nuclear could recharge in a couple of weeks and solar around 9 months depending upon final configuration.
I think it is time for fresh thinking in this arena. Perhaps we are trying to do the equivalent of flying to NY and back without realizing the need for a major airport at our destination? A single or even a dozen flights would be very expensive since we would have to take all of our fuel with us and landing/take-off would be difficult at best. The massive investment to build an international airport is not obvious to early air travelers, just as the need to build/invest in space facilities to reduce the costs of LEO are not obvious to us today. The key question is what would be the payback period and how long would the facility last in orbit?
How much would it be worth to the space, tourist industry if costs to LEO and to orbit near the moon were brought down to around $50/lb? Would an investment of 100 billion be cost-effective? What about 200 billion? The key is projecting tourist demands since they will be the initial paying customers.

A STO,
on the other hand, would be made on Earth and would be several orders of
magnitude cheaper, and they so they are the next logical research target
until all possibilities are exhausted.
From your text above, I think that the site that you linked in your other
message proposes other kinds of space tethers; unfortunately, the site was
down when I tried to access it. Would you please explain briefly the
principles involved?
Tom - Pictures are really needed to illustrate, but I will give a high-level overview. The tether rotates much like a croquette mallet if tossed into the air. The counter-weight is about 100 to 200 tons and includes a power source to boost orbit using current interaction with the earth's magnetic field. The end of the tether has a grapeling device that dips down into the atmosphere just when a space plane is at the peak of it's "pop up" and it grabs the payload and pulls it into orbit. See the tether web site for papers for details. There are over 150 of them, and NASA is funding some of the research.
Drawbacks:
1) orbital velocity may not be provided by the tether.
2) rendezvous between tether and payload may be dicy at best,
3) There may be a better way than using a tether.

Regards,

Tom Tucker
Zubrin also points out that the major rocket manufacturers have absolutely
no incentive to reduce the cost to LEO since they feel that they would be
cutting their own financial throat. Independent efforts are indicated and,
IMO, the winner may not be flown from US soil at the rate we are going now.
No wonder that the LightCraft project is under USAF, if I remeber
correctly...
Cheers,
Cheers,
Tom
Lucio

From: "Tom Tucker (Olympia)"
To:
Sent: Tera-feira, 12 de Dezembro de 2000 03:39
Subject: Re: [spacesettlers] Mining the Sky & Space Tethers to achieve LEO

[snikt]
Tom - Pictures are really needed to illustrate, but I will give a
high-level overview. The tether rotates much like a croquette mallet if
tossed into the air. The counter-weight is about 100 to 200 tons and
includes a power source to boost orbit using current interaction with the
earth's magnetic field. The end of the tether has a grapeling device that
dips down into the atmosphere just when a space plane is at the peak of it's
"pop up" and it grabs the payload and pulls it into orbit. See the tether
web site for papers for details. There are over 150 of them, and NASA is
funding some of the research.

Meanwhile, I tried again and successfully accessed the site this time, so I
saw the pictures; also, I downloaded one of the papers ("Hypersonic Airplane
Space Tether Orbital Launch (HASTOL) System: Interim Study Results", by
Thomas J. Bogar et al. 9th International Space Planes and
Hypersonic Systems and Technologies Conference 1-5 November 1999, Norfolk,
VA USA.) and Ill read it occasionally. Anyhow... the concept is amazingly
ingenious! Im very well impressed with it and hoping that someday it will
be implemented. It is "the space tether for now", a much more feasible
project than the traditional concept of geosynchronic tethers (first
presented by Tsiolkovsky about a hundred years ago, I think).

[snikt]
Regards,

Regards,

Tom Tucker
[snikt]

Lucio Coelho

>
> I just finished reading an amazing book Mining the Sky by John S.
Lewis. He presents some mind-stretching scenarios for us to ponder.
Key points:

I have read the book to so I have at least a basis to comment.
>
> 1) The resources in the asteroid belts are vast

The resource in the asteroid are vast, but so are the ones on earth.
The earth represents at least 9 orders of magnitude more material than
all the asteroid combined. If you can effectively mine the first
kilometer of the surface you will get everything you need, assuming an
energy source can be found.
>
> 2) Fusion energy is essential for stellar space travel and Uranus
has plenty of He3 and a low gravity well to make mining the most
practical of the gas giants. He3 is ideal for fusion since very
little output is in the form of neutrons hence very hot plasma is the
principle outlet which would make an ideal rocket engine as well as
generator of electricity if run through a magnetic coil of wire.
>
Again, no. If you are looking for a continuous acceleration engine for
interplanetary travel, you can achieve this by using solar powered
electric generators, to charge dust particles, then accelerate the
dust using an electric field.

As for fusion, the most successful fusion experiments were done in the
late fifties using muon catalyzed fusion. Inject a stream of negative
muons into a deutrium, the muons display the electrons in the outer
shell, and because the muon is 200 times more massive than the
electrons the muon orbitals are actually smaller than the fusion
radius. This allowed deutrium atoms to approach each other because
they were neutral particles. When they fused, the muons were both
kicked out to start all over again. The problem was the 15 minute half
life of a muon was to short for it to catalyze enough reactions.

As far as I know, no research i this area has been done since the
early sixties.

> 3) Space colonies can support many billions of people.
>
I have a spread sheet that gives rough estimates of around 10^13
before space colonies start having problems.

> Highly recommended reading.
>
Yes it is. He has a very interesting writing style, and the topic is
one you would be interested in.

> My spin, key issue, is that we must achieve reduced cost to achieve
LEO because without it, space colonies will remain in the distant
future.
>

I agree. With today's technology that means a coil gun of some sort.

Bill

--- bill t wrote:
> >
> > I just finished reading an amazing book Mining the
> Sky by John S.
> Lewis. He presents some mind-stretching scenarios
> for us to ponder.
> Key points:
>
> Bill: I have read the book to so I have at least a
basis
> to comment.
> >
> > 1) The resources in the asteroid belts are vast
>
> The resource in the asteroid are vast, but so are
> the ones on earth.
> The earth represents at least 9 orders of magnitude
> more material than
> all the asteroid combined. If you can effectively
> mine the first
> kilometer of the surface you will get everything you
> need, assuming an
> energy source can be found.
> >

MW: Of course the problem with mining the Earth's
surface is the fact that there is-- life on it. There
would be no such problem with mining the asteroids.

Marcel F. Williams
12/19/00

>
> MW: Of course the problem with mining the Earth's
> surface is the fact that there is-- life on it. There
> would be no such problem with mining the asteroids.
>
> Marcel F. Williams
> 12/19/00
>

Start with an open pit mine 10 km in diameter with a depth of 5 km.
Now start escavating tunnels in all direction in an orderly honeycomb
structure leaving 80% of the material intact. The tunnels can go into
the ground approximatey 100 km in all direction. At the hundred km
mark dig another open pit mine as before, and form a hexagonal network
of open pit mines.

This allows you to escavate the entire planet while only disturbing
10% of the surface. You can also go much deeper than 5 km.

Bill

bill t wrote:

>> 2) Fusion energy is essential for stellar space travel and Uranus

> Again, no. If you are looking for a continuous acceleration engine for
> interplanetary travel, you can achieve this by using solar powered
> electric generators, to charge dust particles, then accelerate the
> dust using an electric field.

Technically that does count as a fusion power source ;-)

From: bill t
To: spacesettlers@egroups.com
Sent: Tuesday, December 19, 2000 4:53 PM
Subject: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

>
> I just finished reading an amazing book Mining the Sky by John S.
Lewis. He presents some mind-stretching scenarios for us to ponder.
Key points:

I have read the book to so I have at least a basis to comment.
>
> 1) The resources in the asteroid belts are vast

The resource in the asteroid are vast, but so are the ones on earth.
The earth represents at least 9 orders of magnitude more material than
all the asteroid combined. If you can effectively mine the first
kilometer of the surface you will get everything you need, assuming an
energy source can be found.
>
Tom - The nice thing about asteroids is that they are already in orbits that would make them worth their weight in gold if we had to launch them from earth. Also, instead of having to dig down a KM to reach an ore body, it is already there in small pieces, just waiting for processing.

> 2) Fusion energy is essential for stellar space travel and Uranus
has plenty of He3 and a low gravity well to make mining the most
practical of the gas giants. He3 is ideal for fusion since very
little output is in the form of neutrons hence very hot plasma is the
principle outlet which would make an ideal rocket engine as well as
generator of electricity if run through a magnetic coil of wire.
>
Again, no. If you are looking for a continuous acceleration engine for
interplanetary travel, you can achieve this by using solar powered
electric generators, to charge dust particles, then accelerate the
dust using an electric field.

Tom - The next generation after the VASIMR engine may verywell be fusion driven. Scientific American has some excellent articles in this regard: See page 90+ in the 11/2000 issue for the VASIMR, and p. 40+ in the Aug. 98 for latest on fusion and the Z pinch approach. Very promising.

As for fusion, the most successful fusion experiments were done in the
late fifties using muon catalyzed fusion. Inject a stream of negative
muons into a deutrium, the muons display the electrons in the outer
shell, and because the muon is 200 times more massive than the
electrons the muon orbitals are actually smaller than the fusion
radius. This allowed deutrium atoms to approach each other because
they were neutral particles. When they fused, the muons were both
kicked out to start all over again. The problem was the 15 minute half
life of a muon was to short for it to catalyze enough reactions.

As far as I know, no research i this area has been done since the
early sixties.

> 3) Space colonies can support many billions of people.
>
I have a spread sheet that gives rough estimates of around 10^13
before space colonies start having problems.

> Highly recommended reading.
>
Yes it is. He has a very interesting writing style, and the topic is
one you would be interested in.

> My spin, key issue, is that we must achieve reduced cost to achieve
LEO because without it, space colonies will remain in the distant
future.
>

Tom - checkout the possibilities at www.teathers.com and then think nuclear power. Extrapolate with your imagination. Distant future? Yes, but at least we have a direction.

I agree. With today's technology that means a coil gun of some sort.

Tom - exactly what is a coil gun and who is working on it? Saddam?

Bill

From:
bill t
To:
spacesettlers@egroups.com
Sent:
Tuesday, December 19, 2000 4:53 PM
Subject:
[spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO
>
> I just finished reading an amazing book Mining the Sky by John S.
Lewis. He presents some mind-stretching scenarios for us to ponder.
Key points:
I have read the book to so I have at least a basis to comment.
>
> 1) The resources in the asteroid belts are vast
The resource in the asteroid are vast, but so are the ones on earth.
The earth represents at least 9 orders of magnitude more material than
all the asteroid combined. If you can effectively mine the first
kilometer of the surface you will get everything you need, assuming an
energy source can be found.
>
Tom - The nice thing about asteroids is that they are already in orbits that would make them worth their weight in gold if we had to launch them from earth. Also, instead of having to dig down a KM to reach an ore body, it is already there in small pieces, just waiting for processing.

> 2) Fusion energy is essential for stellar space travel and Uranus
has plenty of He3 and a low gravity well to make mining the most
practical of the gas giants. He3 is ideal for fusion since very
little output is in the form of neutrons hence very hot plasma is the
principle outlet which would make an ideal rocket engine as well as
generator of electricity if run through a magnetic coil of wire.
>
Again, no. If you are looking for a continuous acceleration engine for
interplanetary travel, you can achieve this by using solar powered
electric generators, to charge dust particles, then accelerate the
dust using an electric field.
Tom - The next generation after the VASIMR engine may verywell be fusion driven. Scientific American has some excellent articles in this regard: See page 90+ in the 11/2000 issue for the VASIMR, and p. 40+ in the Aug. 98 for latest on fusion and the Z pinch approach. Very promising.
As for fusion, the most successful fusion experiments were done in the
late fifties using muon catalyzed fusion. Inject a stream of negative
muons into a deutrium, the muons display the electrons in the outer
shell, and because the muon is 200 times more massive than the
electrons the muon orbitals are actually smaller than the fusion
radius. This allowed deutrium atoms to approach each other because
they were neutral particles. When they fused, the muons were both
kicked out to start all over again. The problem was the 15 minute half
life of a muon was to short for it to catalyze enough reactions.
As far as I know, no research i this area has been done since the
early sixties.
> 3) Space colonies can support many billions of people.
>
I have a spread sheet that gives rough estimates of around 10^13
before space colonies start having problems.
> Highly recommended reading.
>
Yes it is. He has a very interesting writing style, and the topic is
one you would be interested in.
> My spin, key issue, is that we must achieve reduced cost to achieve
LEO because without it, space colonies will remain in the distant
future.
>

Tom - checkout the possibilities at
www.teathers.com
and then think nuclear power. Extrapolate with your imagination. Distant future? Yes, but at least we have a direction.
I agree. With today's technology that means a coil gun of some sort.
Tom - exactly what is a coil gun and who is working on it? Saddam?
Bill

Bill,

Another problem with mining the earth is that it has been heated so that most metals have been drawn to the center of the earth thus leaving the silicone oxides with a few magma intrusions at the surface for us to mine. However, asteroids, which have not been heated from collective buildup of heat from radioactive decay, are an excellent source of minerals and metals that most likely represent what we would find if we could mine the earth's core. Again, much easier access.

The earth is fine for earthlings, at least for now, but space resources are for space inhabinents who can sell weak metals like gold to earthlings for cash. :-)

Tom
From: bill t
To: spacesettlers@egroups.com
Sent: Tuesday, December 19, 2000 5:48 PM
Subject: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

>
> MW: Of course the problem with mining the Earth's
> surface is the fact that there is-- life on it. There
> would be no such problem with mining the asteroids.
>
> Marcel F. Williams
> 12/19/00
>

Start with an open pit mine 10 km in diameter with a depth of 5 km.
Now start escavating tunnels in all direction in an orderly honeycomb
structure leaving 80% of the material intact. The tunnels can go into
the ground approximatey 100 km in all direction. At the hundred km
mark dig another open pit mine as before, and form a hexagonal network
of open pit mines.

This allows you to escavate the entire planet while only disturbing
10% of the surface. You can also go much deeper than 5 km.

Bill

Another problem with mining the earth is that it has been heated so that most metals have been drawn to the center of the earth thus leaving the silicone oxides with a few magma intrusions at the surface for us to mine. However, asteroids, which have not been heated from collective buildup of heat from radioactive decay, are an excellent source of minerals and metals that most likely represent what we would find if we could mine the earth's core. Again, much easier access.

The earth is fine for earthlings, at least for now, but space resources are for space inhabinents who can sell weak metals like gold to earthlings for cash. :-)

Tom
From:
bill t
To:
spacesettlers@egroups.com
Sent:
Tuesday, December 19, 2000 5:48 PM
Subject:
[spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO
>
> MW: Of course the problem with mining the Earth's
> surface is the fact that there is-- life on it. There
> would be no such problem with mining the asteroids.
>
> Marcel F. Williams
> 12/19/00
>
Start with an open pit mine 10 km in diameter with a depth of 5 km.
Now start escavating tunnels in all direction in an orderly honeycomb
structure leaving 80% of the material intact. The tunnels can go into
the ground approximatey 100 km in all direction. At the hundred km
mark dig another open pit mine as before, and form a hexagonal network
of open pit mines.
This allows you to escavate the entire planet while only disturbing
10% of the surface. You can also go much deeper than 5 km.
Bill

>
> Tom - exactly what is a coil gun and who is working on it? Saddam?
>
> Bill
>
Actually the American military have a working prototype of a coilgun
used as a weapon.

A coil gun is a what O'neil called a mass launcher.

Given a coil gun 1500 km long, and an aceleration of 5 g while in it,
will produce escape velocity. You would have to have the top of the
gun above most of the atmosphere to keep the capsule being shot from
slowing down too much.

To get above the atmosphere. Build a mountain 10km high. This sounds
ludicrous, but it is feasible. The second method is the one Mike Combs
came up with. Use Buckministers giant balloons as support. I like that
method myself, but its a lot of ballons (over 3000).

Bill

>
> The earth is fine for earthlings, at least for now, but space
resources are for space inhabinents who can sell weak metals like gold
to earthlings for cash. :-)
>
Depending on the price of transport, you might want to use gold as
wiring in the colonies.

Let put the question out this way.

What is the biggest, most advanced, terrestrial civilization you can
imagine?

Are we near this limit or do we have an extra 1000 years to get to it?

I can argue that we have reached the natural carrying capacity of the
planet. With active effort, we can artificially maintain a higher
carrying capacity on earth. How much effort, and how much higher can
the carrying capacity be artificially raised?

Bill

From: "bill t"
To:
Sent: Tera-feira, 19 de Dezembro de 2000 23:48
Subject: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

[snikt]
> Start with an open pit mine 10 km in diameter with a depth of 5 km.
> Now start escavating tunnels in all direction in an orderly honeycomb
> structure leaving 80% of the material intact. The tunnels can go into
> the ground approximatey 100 km in all direction. At the hundred km
> mark dig another open pit mine as before, and form a hexagonal network
> of open pit mines.
>
> This allows you to escavate the entire planet while only disturbing
> 10% of the surface. You can also go much deeper than 5 km.
>

Ok, but *where* are you going to put all the material that you excavated? It
seems to me that it would cover vast amounts of Earths surface. And, even
though if Im misunderstanding some point and your method would really
affect only 10% of Earths surface, that alone would be an unprecedented
environmental catastrophe. 10% of the planetary surface is something like 50
million square kilometers; it is like adding or subtracting a whole
continent (not a small continent like Australia, but a big one like Asia).
Think about the disturbance of the atmospheric and oceanic patterns, the
combination of atmospheric gases with underground minerals and the potential
release of volcanic gases, and probably youll have a mess big enough to
cause a mass extinction event.

> Bill
[snikt]

Lucio

bill t wrote:

>> Tom - exactly what is a coil gun and who is working on it? Saddam?
>>
>> Bill
>>
>
> Actually the American military have a working prototype of a coilgun
> used as a weapon.
>
> A coil gun is a what O'neil called a mass launcher.

I looked into this stuff a while back.

Coil guns can do about 2.5 km/s which is enough for the
moon (or punching though armour plate), but I think it runs
out of 'steam' after that. The inductance of the coils gets
to be a huge problem.

Rail guns have a higher top speed. Atleast that's what
I heard.

Rail guns don't have a theoretical top speed- they don't have
much inductance. I think they're up around 3 or 4 km/s,
state of the art- the rails tend to erode when you launch
and that's a bit of a problem really.

Then there's the Jules Verne gun (light gas gun). This can
handle 5+km/s. There's no limit to the top speed of this
one that I'm aware of. Even a table top example outperforms
a Coil gun.

Actually the military are interested in this, but not quite
as interested as you might think. One problem is that
they tend to leave a rather too neat hole. The military like
more of a mess ;-)

From: Ian Woollard
To: spacesettlers@egroups.com
Sent: Thursday, December 21, 2000 9:11 PM
Subject: Re: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

bill t wrote:

>> Tom - exactly what is a coil gun and who is working on it? Saddam?
>>
>> Bill
>>
>
> Actually the American military have a working prototype of a coilgun
> used as a weapon.
>
> A coil gun is a what O'neil called a mass launcher.

I looked into this stuff a while back.

Coil guns can do about 2.5 km/s which is enough for the
moon (or punching though armour plate), but I think it runs
out of 'steam' after that. The inductance of the coils gets
to be a huge problem.

Tom - I am concerned about mass drivers being used in orbits where space habitats will reside. You see, each pellet or rock become a projectile which, if launched into the right orbit, will eventually return as an earth crossing object. Only if the projectiles were fired in a direction retrograde to earth's orbit would they be safe for long-term use.
Nuclear powered plasma rockets are my preference. In space around the earth, power can be sent from the moon or space station to the " space tug" via microwaves since aroung 10 MW would be needed. With an ISP of 3000 to 30,000 for a VASIMR rocket, why use anything else? Just use H2 for fuel.

Rail guns have a higher top speed. Atleast that's what
I heard.

Rail guns don't have a theoretical top speed- they don't have
much inductance. I think they're up around 3 or 4 km/s,
state of the art- the rails tend to erode when you launch
and that's a bit of a problem really.

Then there's the Jules Verne gun (light gas gun). This can
handle 5+km/s. There's no limit to the top speed of this
one that I'm aware of. Even a table top example outperforms
a Coil gun.

Actually the military are interested in this, but not quite
as interested as you might think. One problem is that
they tend to leave a rather too neat hole. The military like
more of a mess ;-)
Tom - I suspect that a neat or jagged hole in an incoming warhead would be just fine :-) provided it could be targeted. I suspect that the military is focusing on chemical UV or soft X ray lasers as weapons of choice for warhead destruction.

> Bill

From:
Ian Woollard
To:
spacesettlers@egroups.com
Sent:
Thursday, December 21, 2000 9:11 PM
Subject:
Re: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO
bill t wrote:
>> Tom - exactly what is a coil gun and who is working on it? Saddam?
>>
>> Bill
>>
>
> Actually the American military have a working prototype of a coilgun
> used as a weapon.
>
> A coil gun is a what O'neil called a mass launcher.
I looked into this stuff a while back.
Coil guns can do about 2.5 km/s which is enough for the
moon (or punching though armour plate), but I think it runs
out of 'steam' after that. The inductance of the coils gets
to be a huge problem.
Tom - I am concerned about mass drivers being used in orbits where space habitats will reside. You see, each pellet or rock become a projectile which, if launched into the right orbit, will eventually return as an earth crossing object. Only if the projectiles were fired in a direction retrograde to earth's orbit would they be safe for long-term use.
Nuclear powered plasma rockets are my preference. In space around the earth, power can be sent from the moon or space station to the " space tug" via microwaves since aroung 10 MW would be needed. With an ISP of 3000 to 30,000 for a VASIMR rocket, why use anything else? Just use H2 for fuel.
Rail guns have a higher top speed. Atleast that's what
I heard.
Rail guns don't have a theoretical top speed- they don't have
much inductance. I think they're up around 3 or 4 km/s,
state of the art- the rails tend to erode when you launch
and that's a bit of a problem really.
Then there's the Jules Verne gun (light gas gun). This can
handle 5+km/s. There's no limit to the top speed of this
one that I'm aware of. Even a table top example outperforms
a Coil gun.
Actually the military are interested in this, but not quite
as interested as you might think. One problem is that
they tend to leave a rather too neat hole. The military like
more of a mess ;-)
Tom - I suspect that a neat or jagged hole in an incoming warhead would be just fine :-) provided it could be targeted. I suspect that the military is focusing on chemical UV or soft X ray lasers as weapons of choice for warhead destruction.

Where does all the material we escavate go to now? Its in the
buildings we build, in the products we own, and in the landfills.

If you have that kind of need for resources you will find a place to
put it. You wouldn't be worried about nature, because at that point
the human race better be in control. One of these holes 10 km in
diameter and 5 kilometers long is more material than we have escavated
in our entire history. Right now all waste material in mining
operations get dumped on top of something else. Valleys are filled or
hills are built and planted with trees and grass.

Even if you were worried about it, you only have to find enough space
for one network. The waste from the second could fill the first,
etc...

Finally, what does it matter if we change anything. Are you so foolish
as to believe that the we are able to kill life on earth. Blue green
algae has been here a lot longer than us, has lived through far worst
disasters than us, and its still around. Yes species will go extinct.
That is how life works, if you can't adopt to the new conditions you
go extinct. And just in case anyone is wondering, yes one of those
species may be man. That is everyones unspoken fear, that we may end
up dying in our own shit.

You have obviously missed the point though. The point is, if we have a
cheap enough energy source on earth we don't need to go out into
space. The resource argument doesn't work. The argument that does is
the cheap energy source.

>
> [snikt]
> > Start with an open pit mine 10 km in diameter with a depth of 5
km.
> > Now start escavating tunnels in all direction in an orderly
honeycomb
> > structure leaving 80% of the material intact. The tunnels can go
into
> > the ground approximatey 100 km in all direction. At the hundred km
> > mark dig another open pit mine as before, and form a hexagonal
network
> > of open pit mines.
> >
> > This allows you to escavate the entire planet while only
disturbing
> > 10% of the surface. You can also go much deeper than 5 km.
> >
> Ok, but *where* are you going to put all the material that you
excavated? It
> seems to me that it would cover vast amounts of Earths surface.
And, even
> though if Im misunderstanding some point and your method would
really
> affect only 10% of Earths surface, that alone would be an
unprecedented
> environmental catastrophe. 10% of the planetary surface is something
like 50
> million square kilometers; it is like adding or subtracting a whole
> continent (not a small continent like Australia, but a big one like
Asia).
> Think about the disturbance of the atmospheric and oceanic patterns,
the
> combination of atmospheric gases with underground minerals and the
potential
> release of volcanic gases, and probably youll have a mess big
enough to

>
> Coil guns can do about 2.5 km/s which is enough for the
> moon (or punching though armour plate), but I think it runs
> out of 'steam' after that. The inductance of the coils gets
> to be a huge problem.

This was only a problem for short, in the order of meters, coilguns,
for long ones it would be less of a problem. For a earth launch
limiting acceleration to 5 gs the coil gun would have to be over 1000
km long.

>
> Then there's the Jules Verne gun (light gas gun). This can
> handle 5+km/s. There's no limit to the top speed of this
> one that I'm aware of. Even a table top example outperforms
> a Coil gun.

A gentleman by the name of Gerald Burns was able to build guns capable
of suborbital launches in the 1970's. He was mysteriously assisinated,
and his research is top secret. Even his undergraduate thesis is top
secret.

>
> Actually the military are interested in this, but not quite
> as interested as you might think. One problem is that
> they tend to leave a rather too neat hole. The military like
> more of a mess ;-)
>
The neat little holes is what kept it from making it past the
prototype phase.

Bill

From: "bill t"
To:
Sent: Sbado, 23 de Dezembro de 2000 19:46
Subject: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

>
> Where does all the material we escavate go to now? Its in the
> buildings we build, in the products we own, and in the landfills.
>

That is, you admit that the material excavated from your network would have
to go somewhere and this "somewhere" would be on Earth itself. Therefore, my
argument holds.

[snikt]
> Finally, what does it matter if we change anything. Are you so foolish
> as to believe that the we are able to kill life on earth. Blue green
> algae has been here a lot longer than us, has lived through far worst
> disasters than us, and its still around. Yes species will go extinct.

I never insinuated in my message that Humanity could extinct life on Earth,
and I wonder how you could interpret such a thing. What I meant, and
continue to maintain, is that your network would completely disrupt our
present biosphere.

As for your question "what does it matter if we change anything", well,
maybe you dont have enough sensibility to appreciate the fact that we are
the only natural complex biosphere that we know - and probably the only one
that Humanity will ever know. But I do have. Also, while there have been
worst disasters in natural history, we are a potential "disaster" that,
unlike the other ones (asteroid crashes, ice ages, continental drift, etc)
have consciousness and moral, and I dont like to bear part of the
responsibility of the current degradation of Earth, and I would like much
less to support a *really* degrading project like your network.

> That is how life works, if you can't adopt to the new conditions you
> go extinct. And just in case anyone is wondering, yes one of those
> species may be man. That is everyones unspoken fear, that we may end
> up dying in our own shit.
>

Paraphrasing you: are you so foolish that you think that Humanity wouldnt
end up dying in its own shit long before your network was finished?

> You have obviously missed the point though. The point is, if we have a
> cheap enough energy source on earth we don't need to go out into
> space. The resource argument doesn't work. The argument that does is
> the cheap energy source.
>

I think that youre the one who missed entirely the point in this whole
discussion. It all begun with a message from Tom Tucker where he simply said
that "The resources in the asteroid belts are vast", with no further
statement. Youre the one who is assuming that he implied that the vastness
of the resources in space would be a motivation to go there.

But if you assume that Humanity will become a race of planet eaters (as you
seems to suggest with your scenarios of complete and careless exploration of
Earths natural resources), than Earth certainly will not be enough. Nothing
is enough when you consider unbound geometric expansion...

[snikt]
Lucio Coelho

> have consciousness and moral, and I dont like to bear part of the
> responsibility of the current degradation of Earth, and I would like

Why do you think we are degrading the Earth?

Bill

From: "bill t"
To:
Sent: Sunday, December 24, 2000 9:40 PM
Subject: [spacesettlers] Re: Mining the Sky & Space Tethers to achieve LEO

[snikt]
> Why do you think we are degrading the Earth?
>

Sorry, that was indeed to vague. I should better say that we are degrading
Earths biodiversity. Human activity is causing the extinction of animal and
vegetal species (mostly through the destruction of their habitats) at a rate
so high that it is often compared with natural mass extinction events
occurred in the past.

> Bill
[snikt]

Lucio

By the same argument though we can say by altering the natural
environment, putting stress on the life forms that lived there to
evolve into better more adaptable animals.

Yes, humanities action has decreased the biodiversity of the planet,
but we too are part of the biosphere. If other creatures can't adapt
to us perhaps they should go extinct. Similarily if we can't adapt to
other creatures maybe we should go extinct.

I don't know what stats you have seen but the natural extinction
events took out 50-90% of all species on the planet. I doubt were
anywhere that high. Remember our growth took a thousand years it
wasn't a catastrophic event. The organisms we affected directly or
indirectly had time to change or migrate away.

Bill

>
> [snikt]
> > Why do you think we are degrading the Earth?
> >
> Sorry, that was indeed to vague. I should better say that we are
degrading
> Earths biodiversity. Human activity is causing the extinction of
animal and
> vegetal species (mostly through the destruction of their habitats)
at a rate
> so high that it is often compared with natural mass extinction
events

--- In spacesettlers@egroups.com, "bill t" wrote:
> >
> To get above the atmosphere. Build a mountain 10km high. This sounds
> ludicrous, but it is feasible. The second method is the one Mike
Combs
> came up with. Use Buckministers giant balloons as support. I like
that
> method myself, but its a lot of ballons (over 3000).

I just wanted to mention that I did not invent this idea. I pinched
it from the "Wildcards" chapter of Gerard O'Neill's "2081: A Hopeful
View of the Human Future". Also, I've corresponded with a
physicist/inventor who claims that he had the idea before O'Neill did.

Rgds,
Mike Combs

I came up with the idea pretty much independantly too about 15 years
ago when I first read about the giant ballons concept.

I only attributed them to you because yours is the only story I know
of where the idea was used.

Bill

--- In spacesettlers@egroups.com, "Mike Combs" wrote:
> --- In spacesettlers@egroups.com, "bill t" wrote:
> > >
> > To get above the atmosphere. Build a mountain 10km high. This
sounds
> > ludicrous, but it is feasible. The second method is the one Mike
> Combs
> > came up with. Use Buckministers giant balloons as support. I like
> that
> > method myself, but its a lot of ballons (over 3000).
>
> I just wanted to mention that I did not invent this idea. I pinched
> it from the "Wildcards" chapter of Gerard O'Neill's "2081: A Hopeful
> View of the Human Future". Also, I've corresponded with a
> physicist/inventor who claims that he had the idea before O'Neill
did.

> My spin, key issue, is that we must achieve reduced cost to
achieve LEO because without it, space colonies will remain in the
distant future.
>

I believed this for many, many, many years, but now I'm starting to
think maybe the opposite is true. Not until there is significant
industry and human habitat volume in space will there be real
incentive to create cheap access to LEO.

Am I nuts?? Does anyone out there agree with me?

> From: flymuffins [mailto:flyingmuffins@...]
> > My spin, key issue, is that we must achieve reduced cost to
> achieve LEO because without it, space colonies will remain in the
> distant future.
> I believed this for many, many, many years, but now I'm starting to
> think maybe the opposite is true.

I'm not so sure I agree either. Cheap material delivery to LEO certianly,
but not necessarily from earth's surface. In a way, whatever that costs it
will be a loss leader.

Quite frankly though, however we do it we'll also need to raise a certian
minimum lump sum in the billions of dollars reigon, however low someone gets
the cost, which IIRC no one has managed to do yet. :(

ANTIcarrot.

> > My spin, key issue, is that we must achieve reduced cost to
>achieve LEO because without it, space colonies will remain in the
>distant future.
> >
>I believed this for many, many, many years, but now I'm starting to
>think maybe the opposite is true. Not until there is significant
>industry and human habitat volume in space will there be real
>incentive to create cheap access to LEO.
>
>Am I nuts?? Does anyone out there agree with me?

I think you've found the conundrum: costs to orbit are high, a big increase
in launch business volume would bring them down, but there are few business
reasons to go to space that would prompt those higher launch volumes.

That's why I think realists are focusing on a few key markets--tourism (some
rich adventurers will pay a small fortune to be able to brag about doing
something nobody else in their circle has done), gambling (no laws out there
to restrict the wilder side of gambling, plus a lot of gamblers are
excitement junkies looking for the newest fixes), and solar power satellites
(no one honestly assessing the future of the energy market can be optomistic
about the supply-demand equation for energy in the next 50 years).

These three markets could potentially operate even with the current high
costs per pound to orbit, eventually building up the launch volumes
necessary to bring costs down. As a bonus they might also build up the
capacity for in-situ resource utilization (for lunar or martian facilities)
or asteroid mining (for orbital facilities) as a way to bring the costs of
operating in space down. They might even prompt the construction of a space
elevator to bring things from earth to orbit without rockets at all.

BradW