Mining the Sky & Space Tethers to achieve LEO

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