http://www.space.com/scienceastronomy/060201_jupiter_comet.html
But this article made me think about ice as a structural material.
Not that it states anything other than two objects in a Jupiter Lagrange
point are comets (ice)-not rocks-and that makes three asteroid type
objects that are strongly suspected to be ice.
A whole lot of mass of a substance required for any space habitat
sitting in a stable very minimal gravity well could make Patroclus and
Menoetius the most valuable resources in the solar system. If there was
any way to do it I would file a mining claim immediately.
Ice is a wonderful building material for first phase structures. It is
easy to reshape with minimal energy expense and tool wear compared to
any metal or ceramic. Ice was considered for battleship armor. With the
perfect vacuum of space as an insulator, all that is required is to keep
sunlight from melting the ice. The required shadow is automatically
created when we put big solar panels or active systems up to capture the
sunlight for use.
Mining or totally reshaping an ice asteroid for use is much simpler than
rock mining because the energy expense and technology is well within
current capabilities and the surface tension of water can do most of the
required shaping work.
I picture a large mylar (thermal blanket) balloon inside of which is a
frame work consisting of inflated tubes and flat surfaces. The outsides
of the tubes are hydrophilic treated except where ice is not wanted then
it is hydrophobic treated. The frame work on the inside of the balloon
is the structure that we want to build. The inside wall of the balloon
is hydrophobic. The size of the structure that is built is only limited
to the size of the thermal blanket / balloon available.
A simple hydrophilic treated heater coil is placed on the surface of the
asteroid and wetted. The surface tension of the water holds the heater
coil in place and keeps it attached to the asteroid. As the local water
pocket grows some of it is pumped to the balloon and sprayed inside. As
long as the thermal blanket traps enough energy to keep the water liquid
it should disperse evenly across the hydrophilic surfaces.
When the required amount of water has been transferred, Energy is
allowed to escape in a controlled way. There is probably research that
has all ready been done on the mechanical properties of ice that has
been quick cooled vs slow cooled.
Fill the empty spaces with thrust systems, living quarters, storage
spaces, etc. An easily made structure. Maybe not perfect but certainly
an excellent starting point.
Mitchell James
You know, a while back there was a paper which proposed building an enormous torus for some kind of crewed exploratory ship by deploying a balloon form and then pumping it full of water and letting it freeze to ice. I just did a search on space.com, but couldn't find the article I was thinking about there.
Mike Combs
I did a bit more searching around, and found what I was thinking about: http://www.neofuel.com/iceships/ This is from Anthony Zuppero, the guy who promotes "neofuel" and nuclear steam rockets.
Mike Combs
You know, a while back there was a paper which proposed building an enormous torus for some kind of crewed exploratory ship by deploying a balloon form and then pumping it full of water and letting it freeze to ice. I just did a search on space.com, but couldn't find the article I was thinking about there.
http://www.neofuel.com/iceships/
Interesting site. His tone is a little over the top and he jumps from
topic to topic without finishing the current topic. I found his need to
have an inner and outer skin unnecessary. The outer skin would retain
heat making the ice weaker. The words on his chart indicated that ice
had higher tensile strength when it is colder. So any retention of heat
in the ice would be undesirable.
I did some web searching as well.
...Adhesive forces can amount to several thousand pounds per square
inch. Two flat plates pressed together with a film of water in between
would have enormous adhesive strength, far beyond the 14.7 psi of the
atmosphere. The tensile strength of water is variously quoted, but
it is no less than 3,000 psi. You can measure values of this
magnitude by bringing two pistons against a column of thoroughly
degassed water and then measuring the force required to pull them
apart.
http://www-tech.mit.edu/archives/VOL_080/TECH_V080_S0098_P005.txt
Studies of ice "alloys," which now appear to be one of the most prom-
ising avenues of research, have been limited, according to Professor
Kingery. The only serious consideration given the problem wXas the
develop-ment of ice-sawdust mixtures during World War II in connection
with British plans to build a 2-million-ton aircraft carrier out of ice.
The addition of about 15 per cent sawdust, it was found, more than
tripled the tensile strength of the ice. Other and important alloys
developed by Professor Kingery are ice-Fiberglas mixtures. Ice which
contains as little as four volume per cent Fiberglas is 10 times
stronger than pure ice. Natural ice has a tensile strength of 200 pounds
per square inch, whereas one Fiberglas-ice alloy has a tensile strength
of 2,000 pounds per square inch.
http://engineering.dartmouth.edu/~icelab/
The Ice Research Laboratory (IRL) was founded in 1983. Its purpose is to
perform research on the Physics and Mechanics of Ice.
I sent an email to
Erland M. Schulson
George Austin Colligan Distinguished Professor of Engineering
Director, Ice Research Laboratory
asking about information on ice frozen in a vacuum.
Questions:
What methods of drilling/working ice would add the least amount of stress?
What is the best method for defining a structure would require the least
amount of mass lifted from Earth?
Could Water/Oil combinations be used to simulate zero g behavior of water?
There was somebody on the space station that was playing with liquid
mixtures. Did he try anything that could be used in this type of
construction?
What deferential of temperature would cause cracks?
How to trim/balance a torus so that it can be spun up?
Ceramics and glass are cooled slowly to reduce stress. Water?
What would be the stress and tensile strength effect of hot water
droplet deposition? The frame could be reduce to just the wall section
that was being sprayed for the initial frame work creation. Could this
be done without a thermal shield? Even less mass to lift.
Mitchell James
have an inner and outer skin unnecessary. The outer skin would retain
heat making the ice weaker. The words on his chart indicated that ice
had higher tensile strength when it is colder. So any retention of heat
in the ice would be undesirable. Perhaps one would be able to tear off the outer skin and then lay down aluminum foil. Or perhaps even lay down an extremely thin layer of aluminum via vacuum vapor deposition. Other and important alloys
developed by Professor Kingery are ice-Fiberglas mixtures. Ice which
contains as little as four volume per cent Fiberglas is 10 times
stronger than pure ice. Natural ice has a tensile strength of 200 pounds
per square inch, whereas one Fiberglas-ice alloy has a tensile strength
of 2,000 pounds per square inch. I had beenwondering about running steelcables through the water before it froze. I'm sure the same mass offiberglass could be much more finely divided and work even better.
Mike Combs
I am looking for the following:
Fracture of Ice
Guest Editor: E. M. Schulson
December 2001, issue 68/17-18
http://www.elsevier.com/framework_products/promis_misc/efmadvert.htm as
a possible purchase for USD 75 which is a bit extreme for something that
I just want to look at to see if there is anything I would find useful.
Articles are available from www.sciencedirect.com at $30 an article.
The local university terminated their subscription at issue 67.
Mitchell James
--- In ssi_list@... Mitchell James
>
> I am looking for the following:
>
> Engineering Fracture Mechanics
> Fracture of Ice
> Guest Editor: E. M. Schulson
> December 2001, issue 68/17-18
>
> http://www.elsevier.com/framework_products/promis_misc/efmadvert.htm as
> a possible purchase for USD 75 which is a bit extreme for something
that
> I just want to look at to see if there is anything I would find useful.
>
> Articles are available from www.sciencedirect.com at $30 an article.
>
> The local university terminated their subscription at issue 67.
>
> Mitchell James
links from this google search:
http://www.google.com/search?hl=en&lr=&q=%22Schulson%22+%22brittle+compressive+fracture%22
The 2nd link takes you to Schulson's Dartmouth webpage.
TangoMan
I did. Which is where I got the reference to the article.
->Yes, we do. Have a look at a review paper I wrote : "Brittle Failure
->of Ice",Engg. Fracture Mechanics, 2001, p1839-1887. Nothing has
->changed re our understanding of tensile fracture since I wrote the
->paper.
->Interesting idea.
->Good luck.
->Erland S.
->*****
->*****
->Erland M. Schulson
->George Austin Colligan Distinguished Professor
->Thayer School of Engineering
->Dartmouth College
->8000 Cummings Hall
->Hanover, NH 03755-8000
I have run into this before where the paper author requires interested
parties to go through the publisher.
Mitchell James