[meteorite-list] OT: Asteroidal and Lunar Materials

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Sun May 22 11:27:13 2005
Message-ID: <001501c55ee2$b651ef50$2f01a8c0_at_Dell>

I absolutely love it!!"Save Our Astroids"
Talk about a "steel trap mind". Whoops that might no longer be a positive
compliment!!
Another wonderful weave with reality based imagination! Thanks Sterling. I
may not have the math background but I sure am able to follow your
engineered imaginative joutney into the future. Jerry
----- Original Message -----
From: "Sterling K. Webb" <kelly_at_bhil.com>
To: "Meteorite List" <meteorite-list_at_meteoritecentral.com>
Sent: Saturday, May 21, 2005 9:35 PM
Subject: [meteorite-list] OT: Asteroidal and Lunar Materials


> Hi,
>
> A while back there was a mini-thread about the cost of returning
> lunar materials to Earth and the effect of economies of scale on that
> cost. These cost concerns are similar to a much more analyzed topic:
> returning asteroidal materials to Earth. See John Lewis' book "Mining
> The Sky."
> Even so, to date these discussions have been about materials that
> could be obtained on Earth (except for Helium-3). The chief point to
> remember about economies is that they change when the material commodity
> is both required and can not be obtained elsewhere.
>
> Here's an example: Imagine you want to build a bridge out of iron
> across a 100 foot chasm. The simplest way is to take a 100 foot long
> slab of iron (or steel), twenty feet wide and 10 feet thick, and flop it
> down. Inelegant, but a solution.
> More elegant is to take a very thin slab of iron and attach a
> variety of iron trusses underneath it, designed to support the stresses
> of the bridge. You use much less iron and get a bridge just as strong
> or stronger. A more elegant solution.
> Even more elegant is build the above example of a bridge very
> lightly indeed and support it with iron cables from towers. Now we're
> up to Golden Gate elegant, less material, more strength, all gotten by
> subdividing the structural shape into smaller and smaller internally
> braced "voids."
> In older aircraft and race car design, we can see engineers drilling
> rows of big holes in beams and such like to create a more favorable
> strength/weight ratio. You engineers out there know all about this, of
> course.
> The next logical step would be to carry the principle down to the
> micro scale, where what appear to be solid structural members are
> themselves smaller and smaller internally braced voids. But both micro-
> and nano- fabrication is too fantastically expensive to contemplate.
>
> Hey, where do the asteroids (and the Moon) come into this?!
>
> Here it is. You've got all this iron (or natural stainless steel)
> in free orbit, zero gee, or at least, micro-gee. Melt it in a
> cylindrical electric induction furnace and eject it through a special
> nozzle at one end. (The furnace is electric because the sunshine is
> free and in constant supply.)
> The exit nozzle's walls have a multitude of injectors that inject a
> whoppingly large number of bubbles of nitrogen gas into the molten steel
> as it emerges. The injector banks are computer controlled for rate,
> pressure, pulsation pattern, and so forth.
> As the molten asteroidal steel foam exits the furnace into vacuum,
> it expands from the internal expansion of the nitrogen bubbles that have
> been injected into it. The desired goal is to regulate the process so
> that the final product contains a very large number of small voids which
> butt up to each other forming regular and irregular polyhedra with thin
> steel walls separating them.
> The result is a material with a density about 1/3rd that of water,
> twenty times lighter than a piece of steel the same size and shape, a
> structural strength greater than the best aircraft grade aluminum, and a
> strength / weight ratio that is an engineer's dream!
> Because it's fabricated in zero-gee, it can be produced in virtually
> any shape without distortion and made in gigantic sizes limited only by
> the capacity of the furnace producing it. ("You want an I-beam how many
> miles long?")
>
> If any of you out there are engineers, your mouths should be already
> watering. If not, you're no engineer, at least not one in the mold of
> Isabard Kingdom Brunel.
> Do you want to build a bridge across the 29-mile Straight of
> Gibraltar? No problem. Do you want to build a skyscraper five miles
> high? No problem. Do you want to build a Tokyo-sized city that will
> float on the sea? No problem. Do you want to build a...? You get the
> idea.
> From fabrication in zero-gee, the huge pieces of Foam Steel will be
> spun sprayed with an ablative polymer and gently de-orbited into the
> central Pacific Ocean, after which they will be recovered, transported
> to the work site, cleaned of polymer, and put in use.
> Why the Pacific? Well, you know, there are always these silly folks
> who get unreasonably nervous about mile long pieces of steel falling out
> of the sky too near them; it's just good public relations to use the
> middle of the Pacific. Remember, Foam Steel will float! In fact, the
> density of Foam Steel could be only about twice that of Balsa wood!
> Foam Steel will float only 1/3rd submerged. No problem. Hello, Hawaii!
>
> The First Iron Age is over. The Second Iron Age is about to begin.
> Here is the miracle material of which the future will be built, and it
> must come from space because that is the only place where it can be
> made, so the raw material is most economically obtained from asteroids
> (or the Moon).
> It would make no economic sense to boost Earth steel into orbit to
> be re-fabricated as Foam Steel! It is conceivable that the demand for
> Foam Steel could become so great that one might foresee the growth of an
> environmental slash wilderness movement to "Save Our Asteroids!"
> So, study those iron asteroids while you've still got them.
>
>
>
> Sterling K. Webb
>
>
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Received on Sun 22 May 2005 11:27:05 AM PDT