starship-design: Re: Mining vs. Recycling

[TLG.van.der.Linden@tip.nl (Timothy van der Linden)]

Hello again Kelly,

>>I'm not exactly sure what you mean with resource consumptive? Clearly energy
>>shouldn't be a problem, so all that is left is the weight/mass of the
>>recycling equipment. Part of the recycling equipment is refining equipment,
>>that part (though in another form) will also be necessary when you mine.
>>And of course mining equipment does have mass/weight too.
>
>The recycling equipment and chemical suplies to break down the processed
>materials into simpler forms.  Since most things we use are things designed to
>be stable and not break down, they are generally made of stuff thats
>chemically hard to decompose back into its sinpler states.

To not break down by normal thermal cycling or wear and tear isn't so
directly related to chemical decomposition as you suggest. Heat things up a
bit over 200 Centigrade and you'll soon find that they break down or react
with other chemicals quite well.

>(You could use a
>plasma decomposition system to get around that.  But that has its own
>problems, and the result it pure chemicals, no componds.)

Indeed the output of the decomposition equipment is likely not to be in the
compounds we need. But how many and which compounds would we need that can
also be easely mined? (Oil derivatives can be created relative easely from
pure elements as well.) Clearly I'm not talking about things like wood,
paper, cotton, leather. These would be impossible to be recyled close to
their original state. I guess we should avoid using these products, but I
guess that wouldn't be a too big offer.

>Electronics are especially found of HIGHLY complex chemical componds and
>processes.

Really? The amount of chemicals should be rather small, since the number of
significantly different components is rather small. I don't know the exact
substances in all components, but can't imagine any of them needing to be
highly complex in chemical structure. (I can only think of a few metals,
copper, lead, zinc, some simple plastics and maybe a bit of ceramic and
silicon.)

>>About recycling being difficult: It may be much easier than mining in space.
>>Since we have only a decade of real research in recycling and no experience
>>at all in space mining, I doubt if we can make any reasonable guesses about
>>both.
>
>We have centuries of research into recycling, it just was a normal industrial
>concern, without a trendy name and political movement to confuse it.  We also
>have a lot of experience with minning and processing ores of various grades
>and some knowledge of the composition of the space materials (asteroids and
>comet cores) that we'ld process.  

Well, then what makes the kind of recycling we need so much more difficult
than space mining and refining we need?
If asteroid resources are more pure then compounds must be more scarce.
Getting pure elements from trash could be about as easy as mining, except
that mining usualy needs less energy.
(The recycling doesn't have to be like remelting old plastics, it could be
complete decomposition, although that of course could cost more energy.)

>>Hmmm, go all the way to Tau Ceti and do nothing but mining which you could
>>have done at Sol too? (talk about being suicidal ;)
>>Anyhow, even when asteroids have purer ores than Earth, they won't all be
>>readely accessable and may need all tricks in the book to get what we need.
>
>?  I don't follow.  You'ld know what the ore is at Tau C or A centari before
>we sent a ship or probe, and presumably we wouldn't carry a lot of heavy ore
>we could find there just as easy.  Given a return flight or long stay mission
>would need HUGE amounts of material, we couldn't afford to carry it all.

But we could afford to recycle it all. (This is still mining versus recycling.)

>>>>* Recycling is relatively constant and with little surprises.
>>>
>>>Big disagre.
>>
>>Please explain. Only major equipment failure would give such surprises when
>>recycling. What I meant with surprices is that few asteroids will be the
>>same, I'm not so sure that mining for all kinds of materials will be "common
>>practice".
>
>Recycling would have a 'known' feed stock assuming no contamination, and a
>constant suply.  This is vitualy unknown in garbage since thing are always
>dirty, broken, and thrown away in unusually patterns as things break down or
>are consumed.

If we use complete plasma decomposition than that problem would be solved.
Sure here on Earth the energy costs would make it completely inefficient,
however in space it may save time and be more reliable than mining. The
energy costs would really be neglectable compared to what the engine needs.
(If energy was really a problem, the waste heat could be used in a heating
system for the rest of the space ship.)

>Asteroids generally seem to be lose piles of similar materials, generally of
>very high purity.

But even if most are very pure, you'd never know what contamination they'd have.
Anyhow, why bother about contamination. It's relative easy to test what
decontaminations are present both in mined and recycled material.

Timothy