From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.space
Subject: Re: Cost of lunar base
Date: 7 Apr 92 18:05:32 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <ewright.702579490@convex.convex.com> ewright@convex.com (Edward V. Wright) writes:
>In <1992Apr5.154805.6222@ke4zv.uucp> gary@ke4zv.uucp (Gary Coffman) writes:
>
>>Well, that's not totally dumb, but composting is not the most efficient
>>way of supplying nutrients to a limited amount of plants when you look
>>at the mass requirements. Modern agriculture uses artificially produced
>>fertilizers because it's more efficient and cost effective to do so. 
>
>Sure, but what is most efficient for a nation of 200,000,000 people
>may not be most efficient for a colony of 500.  If a fertilizer plant
>costs more to build and operate than a compost heap (and at that scale,
>I think it almost certainly would), you'd use the compost heap.  The
>compost heap also the adantage of being *much* less susceptible to
>mechanical breakdown.

Well lets examine how we get to the compost heap. To make compost,
you need dead plants. To get dead plants, you need live plants, to
get live plants, you need fertilizer. Since fertilizer is heavy,
you'd want to make it from materials on site. So to get a compost
heap, you've first got to build a fertilizer plant. Since you now
have the fertilizer plant, you don't strictly need the compost heap.
But see below.

>>There's no point in 
>>throwing out good organic material. But the cost of generating the 
>>biomass in the first place, just for clothing, doesn't make $ense.
>
>That's true *if* you only get one batch of cotton out of that biomass.
>But we're talking about a permanent colony here, so you would continue
>to get crops out of it year after year.  Also, remember that biomass is
>mostly water, and water is 8/9 oxygen by weight -- the oxygen can be
>extracted from lunar materials, so only the hydrogen has to be imported. 

Ah, if only organic chemistry were that simple all us poor farmers could
retire. Also remember that while recycling is useful, no small scale
recycling effort ever approaches 100% efficiency. You have to continue
to add material at each cycle. Only at the level of complexity of the
Earth's biosphere does recycling work at 100%, and then only on very long
timescales. Since processed cotton is nearly pure cellulose, ordinary 
composting just doesn't do the job. You really need some termites in the 
cycle. As an example of the failure of small biospheres see Biosphere II.

>>It was the orginal poster who stated that *hand* spinning wheels would
>>be manufactured on the Moon from native materials for making cloth. 
>
>Nope.  The original poster (me), simply specified "spinning wheels."  The
>"hand" part was your embellishment. 

Well I just went to the archive and re-read the start of this thread. It
sure reads like you are talking about primitive hand spinning wheels.
Industrially, thread making isn't really done with spinning wheels at
all anymore. They're too hard to operate automatically.

>>Those treatment procedures consume vast quanities of water here on Earth. 
>
>Do they actually *consume* that much water, or do they simply use it and
>expel it as waste that can be recycled?  Big difference.

Well it's considered the number one source of water pollution in the
South. You *could* distill it, but that's a tough and highly energetic
way of recovering the water. Recycling the chemicals used would be less
simple.

>>The fabric industry here on Earth is built up on a system of small job
>>shops that depend on other shops to produce the materials they need and
>>whose output goes to other small job shops that use the material they
>>produce for the next step in the process. The overall operation *is*
>>a multi-billion dollar system that depends on each step being performed
>>properly. 
>
>Again, the overall operation is a multi-billion dollar system because it
>must produce billions of dollars worth of finished goods.  If all you
>wanted to do was supply the needs of a 500-person colony, you wouldn't
>try to recreate that whole system.  Simply scaling everything down probably
>wouldn't work, either.  It's easy to think of reasons why something won't
>work.  The challenge lies in picking the best technology -- and best does
>not necessarily mean newest -- to do the job. 

The systems now in use use the least amount of hand labor of any system
we have ever built. Since I'm claiming that hand labor is expensive, I'm
saying that the way that we *know* uses the least hand labor is a complex
process that uses lots of energy and water. Now if you can come up with
a *workable* process that is (1) simple, (2) uses less hand labor, (3)
masses very little, (4) uses little water, (5) uses little energy, and 
(6) is cheap, then the textile industry would like to hear from you.

>>I consulted on the software for a machine that takes roll cloth and 
>>turns it into finished uniform shirts. The complexity of doing that
>>seemingly trival hand task by machine turned out to be very daunting.
>>The shade marking subsystem alone involves an optical mapping of the
>>cloth roll and a careful pattern layout program that minimizes waste
>>while keeping all the pieces of the shirt the same shade. 
>
>Cutting fabric from a pattern, even if you have to do it manually, is not 
>nearly as labor-intensive as you make it out to be.  It never takes me
>more than a few minutes to cut out even a complex garment; sewing takes
>a lot longer.  Cutting a hundred garments from a stack of fabric takes
>even less time than cutting a single garment by hand -- I've watched
>this done.  It sounds like most of your problems came from the fact
>that you were dealing with a continuous roll and needed to match
>colors exactly.  It's much easier to keep things simple if you aren't
>operating within the constraints of an existing system.

Our machine replaced 37 seamstresses, 4 pattern cutters, and 2 layout
people with 1 machine operator. Our waste was cut from 4% to under 1%.
That savings alone paid for the system in under 6 months.

>Another thing which must be considered is that many people consider
>sewing, gardening, etc. to be fun.  You are going to have to provide
>the colonists with some recreational opportunities in their off time,
>and if they happen to be productive, so much the better.  

*This* is a good reason to divert labor to producing clothing and food.
However, it may not be a sufficient reason to devote all the other
resources necessary to *support* the hand fabrication of clothing.

>>>>Cotton is cotton. It can be recycled no matter where the source of the
>>>>original fiber.
>
>>>Really???  The only way I know of to recycle cotton is by growing cotton
>>>plants.  If you know another way, please tell me.  Don't bother filing a
>>>patent first, I'll take care of that. :-)  
>
>>I guess you've never heard of the old and honored profession of rag picker.
>>Much of the raw mat that is used in thread production is recycled fiber.
>>Rags in better condition are still used for *patchwork* products. And
>>rag fiber is still used for paper production. 
>
>You're going to tell the colonists you want them to wear rags?  Sure, rags
>can be used for cleaning, patchwork projects, etc., but there comes a point
>where they're useless even for that.  Apart from stuffing toys and pillows
>(which may be useless in 1/6-gee anyway), what do you do with them then?
>You already said you believe thread production is impossible.  And paper
>production is another can of worms: The lunar colony will be, perforce, an
>almost paperless society, anyway.

In Colonial days, people rarely had more than one good suit of clothes.
Everything else was patchwork. That's because hand production of cloth
and clothing was so labor intensive and thus expensive. I'm suggesting
that a similar situation would prevail on a Moon colony. Whether the
clothing was made on site or imported, it would be extremely expensive
and in short supply. If the clothing were cotton, it would wear out
much more quickly than some of the modern synthetics that could be
imported for the same cost. It may be that Selene dwellers would wear
no natural fiber clothing at all due to cost.

>>There's a world of difference between picking a ripe tomato and making
>>clothing from raw cotton, both in the amount of labor involved, and in
>>the real time skills required. 
>
>You seem to be hedging.  You said before that neither of these things
>could be done by teleoperators, because of the time delay.  What will
>you concede next?

No hedge. I maintain that spinning of *raw* cotton is impossible thru
a 2 second lag, and that picking a ripe tomato, while possible, is not
a trivial task for teleoperation. Study the motions that you go through
to pick a ripe tomato. It's really a lot more complex than it seems.
The grasp requires force feedback to avoid having the tomato go squish.
There is a twisting motion coupled with a pulling motion that requires
careful coordination to avoid breaking the plant stalk. All with real
time feedback. You normally handle all this subconsciously because of
the real time feedback. With teleoperation, you have to consciously
plan each movement, and because of the variation in natural plant
fiber compliance, your planning won't be very accurate. It'd really be 
a lot easier to *cut* the tomato from the vine, but that damages the 
plant due to fluid loss while proper picking causes a rupture that 
quickly self-seals. 

>>Then there are the economics to be 
>>considered. It takes an unskilled human on site about 10 seconds to
>>select and pick a tomato for his table. Can you build, deliver, and
>>operate a teleoperated tomato picker for the equivalent of 10 seconds
>>of on site human hand labor? I think not. 
>
>If that's true, then life support costs must be a hell of a lot less
>than you've made them out to be.  You can't have it both ways -- claim
>that the cost of supporting humans is so high that they must spend 100%
>of their time doing "multimillion-dollar labor" and that it's cheaper
>to pick tomatoes by hand.  Please make up your mind.

Oh my mind is made up. At $1,000,000 an hour, that 10 second tomato
pick costs $2777.80. I don't think a teleoperator can do it in 10 
seconds, and I don't think the teleoperation equipment can be built,
delivered, and operated cheaper than that. Indeed, at your lift cost
of $250 a pound, an imported tomato only costs $251. Besides that
10 second pick can be part of the transit time to the dinner table,
so it doesn't cut into the worker's productive time.


>>On Earth, a mechanical tomato harvester, with an on site operator, costs 
>>about $100,000 and masses about 10,000 pounds. It burns about 7 gallons 
>>of diesel an hour. Can you design, manufacture, and deliver a teleoperated
>>version for less?
>
>Yes.  Because you're overlooking the matter of scale.  That mechanical
>tomato picker is designed to pick more tomatoes in an hour than a 500-
>person colony would consume in a month.  You might as well compare a
>Boeing model 747 with a Piper Cub.

Per passenger mile, a Piper Cub is *much* more expensive to operate than
a 747, economy of scale. Your little picker is going to be more expensive
than a big picker per each tomato picked.

>>Now remember our on site human tomato picker. If he is doing *other* work 
>>worth $19,346.79 an hour, he can afford to have $251 tomatoes *shipped* 
>>to him. Two a day represent only 0.32% of his salary. This is where the 
>>tradeoff comes between home grown and imported goods.
>
>This assumes he has other work worth $19,000 an hour -- which would put
>him in the Fortune 500 very quickly.  *If* that person has labor that's
>worth that much, the obvious answer is that he should do it, and pay
>someone else to grow his tomatoes for him.  Add one more teleoperator
>or human to the colony.

He'd *better* have high value work to do. Like workers in other inhospitable
places, like the North Slope, where a hamburger is $25 and it's cheaper to
*mail* concrete blocks than ship them by boat, most of his income is going
to be consumed paying for life support. Living where even *air* isn't free
means what you're doing had better be worth a lot.

>And since his body is going to be metabolizing that tomato and turning
>it into carbon dioxide, someone else had damn well better be planting
>*something* to absorb it!

Or using chemical scrubbers, it could be cheaper. With oxygen available
in the rock, it might be cheapest to simply dump the CO2 in a single
stage pass thru system. Closed cycle ecologies appear to be much more
difficult than ordinary engineering solutions to most life support
problems. *No one* has yet built a successful closed ecology that will 
sustain humans for weeks, much less forever.

Gary
Newsgroups: sci.space