Using Concrete to build space ships...

More on crete:

>Date: Fri, 20 Feb 2004 10:40:40 -0800 (PST)
>
>Hi Frank
>
>2) "Yeah and you probably have to dig it out perhaps
>going underground (mining) while I think getting the
>materials for concrete is mainly picking them off the
>ground of asteroids. So youll need no mining
>gear."

Materials suited to concrete are not as generic as you moght think. Witness
Kuwait as an importer of sand for it's concrete. Mixing the asteroid
pickings with a resin would probably work better than regular concrete any
way.

>
>4) "Also to get a decent radiation protection for a
>steel hull youll need thick plates of steel, not just
>thin metal sheets."
>
>I envision thick plates with sharp crenellations so
>that an impact is not head on and distributes the
>energy laterally. Behind them is probably insulation
>of fiberglass then another layer (double hull). After
>this you get into radiation shielding without the
>structural need so water, moon dust or any bulky
>material would do just fine. Plant 6 layers of
>gardens each .5 meter in thickness and you get food
>from your radiation shield.
>

I suggest looking at the military efforts to defeat high and hyper velocity
projectiles for info on meteor protection. They are certainly the undisputed
experts here. A thin metal skin followed by regolith compacted between
another skin would provide the mass necessary to defeat minor impacts, and
have the advantage of localizing the damage, greatly reducing the chance of
structural damage, and minimizing any spalling from such an event (which
would be more widly damaging than the impact itself). Plus it would be alot
easier to maintain... Something that must be considered for our reusable
cycler.

In addition, iron is not easy to weld, due to its tendency to crystallize
around the edges of the weld and become very brittle. Other materials would
be easier to assemble and maintain. However, if this is unable to dissuade
you from Fe use, let me suggest a tounge and grove, or dovetail like
configuration, with bolts to hold it together, underlain with a semi rigid
skeleton.

Val

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