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Re: Engineering Newsletter

> Tim replies to Kelly:

> >>I've doubts about that, a lot of things are unnessary renewed also a lot
> >>effort is used to develop new things, if we would maintain the current
> >>level of technology and not innovate, we probably had a lot more spare
> >
> >Actually most companies only spend about %5 on research and development.
> >rest goes to manufacturing. So I don't expect a big saving there.
> OK, but we don't need much manufacturing after the initial build up. It
> takes much less effort to keep what you have than to build something from
> scratch.
> Also a big amount of the 95% spend on manufacturing are the cost for raw
> materials, I expect the cost of mining raw materials will be less at TC
> because we can pick the easiest sites. No deep-sea oil drilling, most ores
> we need will be somewhere near the surface.

Raw materials will be in space.  MOst of the best ore beds on earth are
crashed asteroids.  We can go to the source!

Its not allways easier to maintain an established thing then to build a new
thing to replace it.  Often its much more expensive to maintain the old thing
then replace it.  Thats especially true of light high performance things like
space ships, trucks, and cars.  We could be a bit more effocent then people
are here on earth, but not dramatically so.  If we could, people would do
that here to save money.  Actually since we'ld be doing things in small
coustom bunches, not large mass production lots like back here on earth.
 We'll be far less efficent in T.C. space.

> I still don't see why it is not possible to scale things down. If you need
> million people to feed 3 million people why can't you do with 100 workers
> for 300 people?

Actually it takes a couple dozen people to feed 3 million people.  But to
maintain a socyiety it takes millions of differnt professions.  You cant
train 100 people, to each do 60,000 professions and do them well.  And we
arn't in a good position to deal with a lot of sloppy workmanship.

> I think a lot of organizational and social professions almost unneeded on
> because it is such a small community that doesn't have direct economic
> >Later in this letter you mentioned this idea again and suggested if
> >were designed to be maintained they would require less replacement.  To a
> >degree true.  But after a couple decades everthing wears out; and the
> >we got used to throwing away things rather than repairing them, is its
> >cheaper and takes less effort.
> Yes, but in those decades you would need much less new materials meaning a
> lot less work. The cheaper-throwing-away habit will not work on TC because
> it will take more effort to build a completely new object than to replace a
> single part. The reason that I mentioned this was not to say that things
> wouldn't wear out, but that the amount of work needed would be less since
> not all parts of the object have to be replaced each time.

Why do you say, a few decades?  What would change after 30 or 70 years?  Are
you expecting better ships or something?


> >>>That asumes the engines can provide the thrust equivelent to 1,000,000
> >>>their own weight.  No engines now made can do that.  The best fusion
> >>>engines I've heard specilated about can do 6 times there weight.  We
> >>>probably expect that to go up to 20, but not a million.
> >> 
> >>OK, take 1 engine that could acclerate itself and 19 other engines, than
> >>other 19 engines didn't need to accelerate themselves anymore so they
> >>use all their power to accelerate the ship.
> >
> >That works for 20 to one.  But you still have the weight of the fuel for
> >one.
> Yes, but now you have 20 engines instead of 1 to push the fuel (the amount
> of fuel is not multiplied by 20 but by less than 20, depending on the
> of the engine).

No the fuel is still multiplied by tweenty. Thats the whole point.

> Here an anti-note (saying you may be right)
> I've tried setting up some formulas, from them it follows that you are
> right, I still don't see why though. (Formulas have a habit of not giving a
> good understanding)
> >> Storing fuel doesn't need much that much facilities.
> >
> >But it does take a lot of facilities to carry and move it.
> But do they need to be serviced all along the trip?

Yes, but not that much when they are shut down.  More importantly they have
to be carried.

> >>  I don't see why good
> >> planets without live could not be used.
> >
> >Probably any planet about earth size would have life (assuming its not
> >radically hot or cold.
> Wow, you are really optimistic. Or are you assuming that most earth-sized
> planets are too hot or too cold?

Earth got life very quickly after it cooled.  Mars may have life.  Then their
is Venus whose crust is wrong which makes it to hoot.  What does that give
you for odds?  And is it an average sample?  Given the extreams of
temperature, radiation, chemistry, etc.. that life lives in on earth.
 (icewater, nuclear reactor cores, water hundreds of centigrade above 0,
deserts) I'ld expect to find life almost anywhere.

> Most Earth sized planets will have a dense atmosphere (not necessary oxigen
> rich). The ones that are cold are too far from their Sun or have too few
> greenhouse gasses. The ones that are too hot are too close to their Sun or
> have too many greenhouse gasses.

Venuses temp is NOT due to its atmosphere.  Its due to its crust, its a
fraction of the thickness of earth crust and doesn't insulate well enough to
keep the surface cool.

> Should too hot or too cold be a problem? Too hot maybe, it is easier to
> something warm than to make something cold. But why are cold planets not

You can get just as dead in liquid air as in liquid metal.  Eiather way your
pushing equipment hard, and without a good survival odds when it fails.

> By the way some people are suggesting on making a real atmosphere on Mars,
> wouldn't that dissolve constantly? 
Yes it would.  But it may be stable for a couple thousand years.  Or you
could artificially renew it as it blows away.  Hard part it gravity. Humans
need it to stay healthy.  

> >Right, thats why I keep talking about space colonies.  Raw materials are
> >easier to get at in space then on a planet.  By mid 21st century we'll
> >probably be moving a lot of our heavy industry of earth and into space for
> >that reason (expect the third world to screem!), so I expect our starship
> >crew would not think of trying to get ore up off a planet.
> I'm not sure, would recycling not have a bigger influence on reducing the
> need for raw materials? Taking all the rubbish down means that the rubbish
> on Earth would increase, and we already have to much of that.

For ecology purposes moving heavy industry off planet would do more than
anything else to ease ecology strain.  Of course their are international
political and cultural problems with that (proably a couple of wars with the
third world).

Stuff can't be recycled forever.  After a while it just doesn't make any
sence.  Right now we in the (throw it all away) U.S. have litle real problem
with waste disposal (though an incredible amount of political problems).
 about 80%-90% of our garbage is paper and similar compustables.  The small
fraction of metals and plastics %5ish, can be broken down or shiped into
space if you crazy enough.  Besides if the industry moves off planet to get
to the resources, the materials to be recycled would need to be shiped up to
be recycled anyway.

> >I was expecting to store standard groceries. Meat, eggs, milk, vegies,
> >breads, pasta all that stuff.  With the exception of the emergency
> >which would be optimized for high nutritian and low weight.  Everything
> >be as standard as possible. Thats why I used food weight numbers for home
> >consumers, not exploration or military missions.
> Huh, you just wrote:
> >To keep down the weight I was figuring NO FOOD RAISING on the ship.
> >20 years of standard frozen foods in cryo, and 20 years of concentrated
> >rations.
> Or did you mean no cows and pigs?

No I ment no food raiseing.  Oh, you can have a couple of tomato plants in
your apartment for recretion.  But farm systems weigh too much if your only
going out for a couple of decades..

> >Well you have to call and end to it sometime.  I figured a couple years in
> >systems would be all we could manage.  Maybe a bit more than 3 years, but
> >certainly not anywhere near 10.  We need to keep the crews round trip time
> >down below 30 years subjective (and not much more than that real time).  I
> >was also expecting a maximum ship service life of about 40 years.
> If the ship doesn't need to travel back anymore a lot of parts are
> many of these parts are that of the engine, and these are the parts that
> wear out most fast and are most hard to replace.
> >> Huh, I can't follow you, am I right that you are against refueling or
> >> building beaming arrays? If so, than the trip may indeed become very
> >difficult.
> >
> >Beaming arrays yes.  I was hoping we could get by on minning fuel for the
> >fusion systems and maybe launching it.
> You would need to mining and refine 1E10 kg of fusion materials, is that
> possible? I don't know, I have no oversight about these numbers, do you
> what is acceptable?

Minning seems easier then processing power converters and microwave systems.
 Don't know where to find that much ore off hand, but in space extreamly rich
resources are common.

> >I was also assuming a larger number of people then you are.  Maybe only a
> >people on the ground, but I expect total research team would be a thousand
> >more.  (Note the size of my ship.)
> Yes, I had never noticed that before. That means that all work can be done
> about 10 times faster.
> >> Yes, we have also very powerful medcines, take penicillin, it has a very
> >> broad range, and can kill many diseases at once, probably a lot of
> >> extraterrestial ones too.
> >
> >The only reason we can use anti-biotics at all is they trip up something
> >suttle in the bacteria they attack.  Even a slight variation of that
> >species is uneffected.  If the stuff effected something biologically
> >fundamental.  It would kil the patent as well as the desease.
> As far as I knew, you have two kinds of anti-biotics, broad-spectre and
> small spectre. The small spectre have less side-effects but can kill fewer
> bacteria. The broad spectre can kill many different kinds of bacteria. But
> OK, I don't know that much about medcine, and I think neither do you. So I
> think we can't really discuss it well. I admit alien creatures will be
> different, but I just can't believe that it would be so different that we
> won't have a single clue how to fight them. I think we just have to
disagree on this untill on of us has more hard data.

I know ther are dozens of differnt anti-biotics each tailored to various
things (and most becoming ineffective), but I don't know much more than that.
 Why would you think we could fight them?