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Technologies for Moon mission useable for missions further out



 
 
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  #11  
Old June 17th 10, 04:36 AM posted to sci.space.tech
Michael Turner[_2_]
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Posts: 27
Default Technologies for Moon mission useable for missions further out


It isn't quite obvious to me that it would be better to grow crops in cav

es than in greenhouses on the surface. I would
expect something like a greenhouse with 10 kP atmospheric pressure, 85% O

2 and 15% CO2 to be workable.
You would need a relatively large volume to grow all the food for a crew.


I think you're laboring under the assumption that I'm proposing the
kind of caves that people would need to stoop to walk into. I'm
not. I'm talking about lava tubes on the Moon and Mars.

Have you heard about those? (I already supplied a link above.)

"A 1969 paper by Oberbeck, Quaide, and Greeley, taking into account
only the Moon's lighter gravity, and not the stronger nature of lunar
anhydrous glass,[1] calculated lunar lavatubes could reach 340 meters
in span (lengths could go to kilometers).[2] There are some
indications in Coombs and Hawke's work (see "Locations" below) that
some lavatubes may be much larger."

http://www.lunarpedia.org/index.php?title=Lava_Tubes

And now we have some data: The lunar lava tube skylight discovered by
some Japanese researchers hole might be almost 400 meters wide at the
point of the skylight.

http://www.planetary.org/blog/article/00002173/

On Mars, with about twice lunar gravity, lava tubes will be smaller.
But the big ones will still be enormous by terrestrial standards.
More than enough volume, if volume is what you're worried about it.

What you should really be worried about with a surface greenhouse:

- wind storms creating structural loads (more mass to take to Mars)
- dust abrasion at the greenhouse's interfaces to the atmosphere
(mechanical wear on air pumps needed to keep it pressurized; filters
clogging up)
- *toxic dust* - http://www.usatoday.com/tech/science/space/2006-08-01-m
ars-storms_x.htm
- very low surface temperatures at night (during which you *will*
need to supply heat just to keep the plants from freezing, as the dome
radiates heat away),
- UV degradation of the greenhouse skin
- maybe plant pathology issues, under occasional solar storms.

In short, pretty much the same problems you'd be dealing with if you
had a sky-exposed greenhouse on the Moon, with some things harder
(wind-blown toxic dust, for example) on Mars, and some things easier
(e.g., where to get your initial CO2.)

I'd bet what would end up working best for both the Moon and Mars is
to concentrate sunlight on the surface and pipe it down into a shelter
set up on the floor of a lava tube. For crops requiring more frequent
light, you might want artificial sources during the long Martian
night.

Even if Martian agriculture could be done robotically, people on Mars
might prefer being more hands-on about their food sources. After all,
they'll be in stuck in a very artificial and limited environment much
of the time; and even where it's natural, it will be starkly desert-
like, very alien and rather dangerous. Growing crookneck squash and
your own fresh basil -- maybe raising chickens, too, and if you can
find/make/take enough water, would fish-farming be too much to ask
for? .... Well, farming might be just the thing to take your mind off
how far you are from home, how hostile the external environment is,
and how many unforeseen variables have popped up in the question of
whether you'll ever be able to get back.

I think food production (and at the same time O2 production from CO2) is

one of the most important (if not the most
important) technology to be developped for space exploration. It is right

up there with cheap access to space.

I wouldn't say so. We have some idea of how to do closed-cycle long-
term human life support. Cheap access to space is a much harder
problem. Moreover, if access to space became _very_ cheap somehow,
would allow you to defer the whole problem of extraterrestrial food
production indefinitely.

The really big question is, I think, psychological: will people really
want to live in space, or just visit? A sustainable human future
might depend on large-scale exploitation of space resources (and on
space as the ultimate industrial effluent sink, the other part of the
equation Gerard O'Neill wanted to address). But even if so, it
doesn't necessarily depend on human presence.

-michael turner

On Jun 15, 11:13 am, Alain Fournier wrote:
Michael Turner wrote:
You're basically compensating for a lot of environmental differences
just to get one thing: sunlight passing through directly to plant
leaves. Is this really more sensible than piping sunlight from a
concentrator on the surface to a more controllable environment below
the Martian surface?


To live economically on the Moon for extended periods, you'll have to
develop some way to grow food in caves. To go to Mars, you'll
(probably) have to develop technologies for growing food aboard ship
-- not too different from growing it in caves. To live on Mars, you'll
have to live underground most of the time -- like you did on the
Moon. Water from the atmosphere? Water vapor content is about 0.0

3%
- of a very thin atmosphere. You're more likely to find acceptably
high concentrations somewhere else -- say, underground?


It isn't quite obvious to me that it would be better to grow crops in cav

es than in greenhouses on the surface. I would
expect something like a greenhouse with 10 kP atmospheric pressure, 85% O

2 and 15% CO2 to be workable. You would need a
relatively large volume to grow all the food for a crew. And space pressu

rized at 101 kP wouldn't be cheap. So it might
be easier to build a low pressure greenhouse exposed to sunlight than to

grow the food in a more Earthly atmospheric
environment with artificial light. I'm not saying one method is superior

to the other. I'm saying that it isn't obvious
to me which is best. Tending to the crop at 10 kP means farming in a pres

sure suit, so it isn't obvious that it is easy.
But, I would expect most of the work to be automated, and once the basic

installation is setup, it should be in many
regards easier than farming on Earth because you don't expect weeds to be

much of a problem nor would the weather be a
problem.

I'm also saying, that if you build a lunar base, the money you invest fig

uring out which is the best method of crop
production, is not money spent solely for the lunar base. It is also mone

y spent preparing martian and/or asteroidal
exploration as the technology is probably easily adaptable. So devellopin

g food production on a lunar base might be more
important than extracting water from the probable polar ice deposits.

I think food production (and at the same time O2 production from CO2) is

one of the most important (if not the most
important) technology to be developped for space exploration. It is right

up there with cheap access to space.

Alain Fournier


  #12  
Old June 17th 10, 04:37 AM posted to sci.space.tech
Dr J R Stockton[_73_]
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Posts: 1
Default Technologies for Moon mission useable for missions further out

In sci.space.tech message ,
Mon, 14 Jun 2010 22:13:37, Alain Fournier
posted:


It isn't quite obvious to me that it would be better to grow crops in
caves than in greenhouses on the surface. I would expect something like
a greenhouse with 10 kP atmospheric pressure, 85% O2 and 15% CO2 to be
workable. You would need a relatively large volume to grow all the food
for a crew. And space pressurized at 101 kP wouldn't be cheap. So it
might be easier to build a low pressure greenhouse exposed to sunlight
than to grow the food in a more Earthly atmospheric environment with
artificial light. I'm not saying one method is superior to the other.
I'm saying that it isn't obvious to me which is best. Tending to the
crop at 10 kP means farming in a pressure suit, so it isn't obvious
that it is easy.


Aside: You mean 10 kPa. P is for poise.

Perhaps not. On Earth, we generally have large quantities of soil found
just lying about the place. Off Earth, soil will be in limited supply
and valuable. It can well be that it will be kept in trays of modest
size, such that a farmer can reach the middle without actually standing
on the stuff.

With "farmland" on trays standing on blocks or tables or with legs, with
aisles between the trays, the robots can easily bring the trays in turn
into a reasonably Earthly atmosphere for planting weeding thinning and
harvesting. It need not be at 100 kPa; the farmers can wear lightweight
non-pressure suits to hold a somewhat enriched breathing atmosphere.

--
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Web URL:http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, & links.
Correct = 4-line sig. separator as above, a line precisely "-- " (RFC5536/7)
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  #13  
Old June 18th 10, 04:14 AM posted to sci.space.tech
Alain Fournier[_2_]
external usenet poster
 
Posts: 373
Default Technologies for Moon mission useable for missions further out

Michael Turner wrote:

I think you're laboring under the assumption that I'm proposing the
kind of caves that people would need to stoop to walk into. I'm
not. I'm talking about lava tubes on the Moon and Mars.

Have you heard about those? (I already supplied a link above.)

"A 1969 paper by Oberbeck, Quaide, and Greeley, taking into account
only the Moon's lighter gravity, and not the stronger nature of lunar
anhydrous glass,[1] calculated lunar lavatubes could reach 340 meters
in span (lengths could go to kilometers).[2] There are some
indications in Coombs and Hawke's work (see "Locations" below) that
some lavatubes may be much larger."


I'm not sure exactly how one would pressurize such lava tubes. It
isn't easy to put 340 m span wall with a 100 kPa difference in pressure
between the inside and the outside. I would think that at first, colonist
would build more modest modules, maybe located inside lava tubes for
radiation and meteorite shelter. But longer term, using the entire volume
of the lava tube is a very interesting prospect. But then again, longer
term, you will probably have much a bigger population and you might want
to use the entire lava tube for human occupation and let the farming
be done in greenhouse on the ground.

http://www.lunarpedia.org/index.php?title=va_Tubes

And now we have some data: The lunar lava tube skylight discovered by
some Japanese researchers hole might be almost 400 meters wide at the
point of the skylight.

http://www.planetary.org/blog/article/00002173/

On Mars, with about twice lunar gravity, lava tubes will be smaller.
But the big ones will still be enormous by terrestrial standards.
More than enough volume, if volume is what you're worried about it.

What you should really be worried about with a surface greenhouse:

- wind storms creating structural loads (more mass to take to Mars)
- dust abrasion at the greenhouse's interfaces to the atmosphere
(mechanical wear on air pumps needed to keep it pressurized; filters
clogging up)
- *toxic dust* - http://www.usatoday.com/tech/science/space/2006-08-01-m
ars-storms_x.htm
- very low surface temperatures at night (during which you *will*
need to supply heat just to keep the plants from freezing, as the dome
radiates heat away),
- UV degradation of the greenhouse skin


I think we can solve the technical issues above, it might not be as easy
as it looks, but we have built lots of stuff that can operate in harsh
environments. I see no reason why the above would be impossible to solve.
I don't know if it would turn out to be cheaper than to do the farming in
the underground module with an Earthly controlled atmosphere, but we
can solve the above issues.

- maybe plant pathology issues, under occasional solar storms.


Yes, that and can plants grow in a gravity field much less than 1 g?
Until we try to do it, we should assume that farming off Earth can
have unexpected difficulties.

Even if Martian agriculture could be done robotically, people on Mars
might prefer being more hands-on about their food sources. After all,
they'll be in stuck in a very artificial and limited environment much
of the time; and even where it's natural, it will be starkly desert-
like, very alien and rather dangerous. Growing crookneck squash and
your own fresh basil -- maybe raising chickens, too, and if you can
find/make/take enough water, would fish-farming be too much to ask
for? .... Well, farming might be just the thing to take your mind off
how far you are from home, how hostile the external environment is,
and how many unforeseen variables have popped up in the question of
whether you'll ever be able to get back.


Not for me, I can't keep plants alive. But yes for some people that
could be a good way of keeping their sanity in such a far out place.


Alain Fournier

  #14  
Old June 18th 10, 04:15 AM posted to sci.space.tech
Alain Fournier[_2_]
external usenet poster
 
Posts: 373
Default Technologies for Moon mission useable for missions further out

Dr J R Stockton wrote:

Mon, 14 Jun 2010 22:13:37, Alain Fournier posted:

It isn't quite obvious to me that it would be better to grow crops in
caves than in greenhouses on the surface. I would expect something like
a greenhouse with 10 kP atmospheric pressure, 85% O2 and 15% CO2 to be
workable. You would need a relatively large volume to grow all the food
for a crew. And space pressurized at 101 kP wouldn't be cheap. So it
might be easier to build a low pressure greenhouse exposed to sunlight
than to grow the food in a more Earthly atmospheric environment with
artificial light. I'm not saying one method is superior to the other.
I'm saying that it isn't obvious to me which is best. Tending to the
crop at 10 kP means farming in a pressure suit, so it isn't obvious
that it is easy.



Aside: You mean 10 kPa. P is for poise.


Yes that is obviously what I meant. Thanks for the correction.

Perhaps not. On Earth, we generally have large quantities of soil found
just lying about the place. Off Earth, soil will be in limited supply
and valuable. It can well be that it will be kept in trays of modest
size, such that a farmer can reach the middle without actually standing
on the stuff.


Someone last year grew some plant in a Moon regolith imitation. It isn't
the most fertile soil but you can grow stuff in it. You then compost the
plants that grew in the regolith to have a fertile ground for farming.
So at first fertile soil would be in limited supply, but with time you
can make as much as you want.

With "farmland" on trays standing on blocks or tables or with legs, with
aisles between the trays, the robots can easily bring the trays in turn
into a reasonably Earthly atmosphere for planting weeding thinning and
harvesting. It need not be at 100 kPa; the farmers can wear lightweight
non-pressure suits to hold a somewhat enriched breathing atmosphere.


Interesting. I hadn't thought about that.


Alain Fournier

  #15  
Old June 19th 10, 01:49 PM posted to sci.space.tech
Michael Turner[_2_]
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Posts: 27
Default Technologies for Moon mission useable for missions further out

On Jun 18, 12:14 pm, Alain Fournier wrote:

"I'm not sure exactly how one would pressurize such lava tubes."

I have not proposed pressurizing lava tubes. I was addressing an
apparent concern of yours: whether they had enough volume for
agriculture. I was merely pointing out that the size of some lunar
lava tubes dwarfs that of any structures (including greenhouses)
currently envisioned for formal Mars missions. The main point of
these lava tubes would be to have a roof over your head that shields
you (and your crops) from CGR, solar storms, dust and temperature
extremes. What you build *inside* them doesn't have to be proof
against those threats -- meaning less mass to take along to Mars, less
time spent in construction of habitats, less maintenance complexity,
more safety in what's otherwise a hostile environment not too
different from that of the Moon.

I don't propose lava tubes as a *substitute* for artificial habitats
or greenhouse, even if they have some speculative potential for that
in colonization scenarios.

Remember, the topic here is "technologies for Moon mission usable for
missions further out".

"... But longer term, using the entire volume of the lava tube is a
very interesting prospect. But then again, longer term, you will
probably have much a bigger population and you might want to use the
entire lava tube for human occupation and let the farming be done in
greenhouse on the ground."

When would that be? When Mars has a population of millions?

Humoring you, for the moment: Look at intermediate stages of economic
development. You seem to be assuming that every inhabited lava tube
must grow its own food. Well, how French of you! ;-)

Why can't some lava tubes become more specialized for food production,
others for habitation, if the initial tube gets too crowded for
farming? There will be no shortage of lava tubes for the time being.

There are major industrialized nations on Earth that get by fine
without 100% food self-sufficiency. I live in densely-populated
Japan. My kiwi fruit comes in from sparsely-populated New Zealand.
Even my "Made in Japan" tofu is mostly soy from the sparsely-populated
United States. I don't buy Japanese wine made from Japanese grapes,
because it's wretchedly awful -- but I do have two bottles of
Australian shiraz at the moment. So if I lived in a lava tube on
Mars, why would I buy my own tube's food, if I could get it cheaper
(or better) by importing from other lava tubes? Or for that matter,
if I could get it shipped down to me from Phobos Farms (TM)? After
all, might be some delicacies that can only be grown in
weightlessness, for all we know.

If Mars starts out a one-tube settlement, and the population grows to
the point where living space is in competition with agricultural
space, eventually somebody will figure out there's a business
opportunity in the higher food prices inevitably resulting. The cost
of space in a neighboring lava tube might be near zero, and the
capital costs of developing that new tube for agriculture, plus the
continuing cost of transporting food back to the old tube, might still
be cheaper than farm-space rent in the old tube. At that "tipping
point", the old tube's farm-spaces turn rapidly toward residential and
commercial uses, the new tube becomes mostly farm-space.

It's a story that's played out for literally thousands of years in
terrestrial economies. Yes, even in France, not so many centuries
ago. It's a story that might play out on the Moon before anybody even
gets to Mars. It's hard to see why the economics of agricultural vs.
residential land use would change dramatically just because you're no
longer on Earth.

In any case, I thought we were talking about lunar mission technology
reusable for Mars missions, in the foreseeable future, not about
colonization.

I think we can solve the technical issues above, it might not be as easy
as it looks, but we have built lots of stuff that can operate in harsh
environments. I see no reason why the above[list of problems with
surface greenhousese] would be impossible to solve.


Engineering is not about what's possible. Lots of things are
possible.

But what gets done? The things that are feasible.

If agricultural equipment engineered for lunar lava tubes ends up over-
engineered in some ways for Mars, at least it's already been
engineered. It might require only slight adaptation for Mars. That
reduces mission development costs and gives you a margin of safety,
with proven equipment, upon arrival. Setting up agriculture on Mars
would take time, during which you might be relying on food drops from
the mothership's closed-cycle (no longer!) garden operations in Mars
orbit. Afterward, if some mission staff happen to have some time to
spare and can afford to take the risks involved, they might
*experiment* with growing stuff in greenhouses on the surface of Mars,
on a small scale, to see if it might be made *feasible* for future
missions. However, even if it turns out to be possible, it will
probably be inferior to growing food in lava tubes in terms of what
matters: price/performance. What you end up using to grow food will
probably be more like what you used on the ship that brought you, in
an environment more like the ship's. Remember: even Martian "dirt"
might not be free: you might have to detoxify it.

If what you're talking about is colonization, that's a different
topic, and a future none of us is likely to see. I thought the topic
was "technologies for Moon mission useable for missions further out".

But even in the colonization scenario: if I lived on Mars, I wouldn't
buy food from surface farms if I could get the same quality at a
better price from farms hosted more cheaply in lava tubes. So even if
the surface greenhouse problem is solvable *technically*, such
greenhouses will end up being only scientific curiosities if they
can't produce food more *economically*.

To repeat: greenhouses on the Martian surface will get exactly one
benefit from being on the surface: direct daytime pass-through of
sunlight at frequencies useful for photosynthesis. That's IT.
Everything else about being on the surface is just a source of added
problems. Solving problems costs money. Money that nobody will pay
if there are cheaper solutions that are just as good.

If some multi-billionaire just HAS to see a beautiful dome with
greenery in it, sparkling under the Martian sky, before he dies, to
fulfill his SF-illustration-fired boyhood dreams of what a Mars base
was *supposed* to look like, with cost no object, well ... then maybe
it'll happen. Where costs matter, it probably won't. Stuff in space
never ends up looking like the "artist's rendition". It always looks
like it was custom-engineered for a highly unusual environment by the
lowest bidder. Funny how that works, eh?

Throw out the SF illustrations. Throw out your old intuitions. On
Earth, the only agricultural product grown in caves is the truffle, an
expensive delicacy. On Mars, maybe tequila will be the drink of
choice for those who feel compelled to consume conspicuously, but only
if it's distilled from those expensive *surface-grown* greenhouse
cacti, with a bottle costing a month's average pay packet.
Connoisseurs will claim to be able to tell the difference. Blind
taste-testing will reveal that they are deceiving themselves, but they
will be undeterred.

-michael turner

  #16  
Old June 19th 10, 01:49 PM posted to sci.space.tech
Robert Heller
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Posts: 17
Default Technologies for Moon mission useable for missions further out

At Thu, 17 Jun 2010 23:15:06 EDT Alain Fournier wrote:

Someone last year grew some plant in a Moon regolith imitation. It isn't
the most fertile soil but you can grow stuff in it. You then compost the
plants that grew in the regolith to have a fertile ground for farming.
So at first fertile soil would be in limited supply, but with time you
can make as much as you want.


Organic waste = soil. This is pretty much where 'fertile' soil on the
earth came from originally. Yes, it takes time. Any colony on the Moon
or Mars will have to deal with various sorts of organic waste somehow.
Composting it into soil is probably the best solution.

--
Robert Heller -- Get the Deepwoods Software FireFox Toolbar!
Deepwoods Software -- Linux Installation and Administration
http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
-- Contract Programming: C/C++, Tcl/Tk



  #17  
Old June 21st 10, 11:48 AM posted to sci.space.tech
Alain Fournier[_2_]
external usenet poster
 
Posts: 373
Default Technologies for Moon mission useable for missions further out

Michael Turner wrote:

On Jun 18, 12:14 pm, Alain Fournier wrote:

"I'm not sure exactly how one would pressurize such lava tubes."

I have not proposed pressurizing lava tubes. I was addressing an
apparent concern of yours: whether they had enough volume for
agriculture.


Well, yes at first you do have enough volume in the lava tubes for
agriculture. But I think, I'm not sure, that agriculture would be
done in a volume which is bigger than the habitat, and that it
would be cheaper to make this volume a lower pressure compartment
than the habitat. Therefore, the farming module and the habitat
module would be quite different from one another. So as you said
below, there is no reason to make it directly part of the habitat
it can be separated. If the plants need protection from radiation
then, making this agriculture module also in the lava tube makes
sense. If the plants can use direct sunlight, I would think that
doing so would be cheaper.


"... But longer term, using the entire volume of the lava tube is a
very interesting prospect. But then again, longer term, you will
probably have much a bigger population and you might want to use the
entire lava tube for human occupation and let the farming be done in
greenhouse on the ground."

When would that be? When Mars has a population of millions?


Yes that's about it. It won't be this decade :-)

You seem to be assuming that every inhabited lava tube
must grow its own food. Well, how French of you! ;-)


I'm a francophone but not French. I have been to France but only visited
it for 15 minutes (the time to wait for the train change going from
Germany to Belgium). But I think France has a very extrovert economy
with lots of imports and exports, I don't know why you would consider
it to be French to grow locally.

Why can't some lava tubes become more specialized for food production,
others for habitation, if the initial tube gets too crowded for
farming? There will be no shortage of lava tubes for the time being.

There are major industrialized nations on Earth that get by fine
without 100% food self-sufficiency. I live in densely-populated
Japan. My kiwi fruit comes in from sparsely-populated New Zealand.


A lovely country. I really liked my trip over there. I hope you don't
buy their japanese grown cantaloupe to often :-) [For those who don't
know Japan, they have some special kind of cantaloupe which is
horrendously expensive, something like 6000 yens or 60 US$ per fruit]

To repeat: greenhouses on the Martian surface will get exactly one
benefit from being on the surface: direct daytime pass-through of
sunlight at frequencies useful for photosynthesis. That's IT.
Everything else about being on the surface is just a source of added
problems. Solving problems costs money. Money that nobody will pay
if there are cheaper solutions that are just as good.


Yes that is the benefit. The benefit of being underground is that
you get radiation protection and I'm not sure that is needed for
plants. The lost of heat, might not be a serious problem either. The
habitat in the cave will be automatically very well insulated because
it is in a vacuum in a cave, you will need to radiate heat away. And
because their is no outside atmosphere (or very little in the case of
Mars) lost of heat is only through radiation. Which benefit and
and which cost are the greatest I don't know. Radiating all the heat
through the greenhouse at night, at least on the Moon is problematic,
so heating the greenhouse at night would probably be done. That is
not very difficult. Is it cheaper to do than to collect the energy
on the surface and sending it to an underground greenhouse, I don't
know.


Alain Fournier

  #18  
Old June 21st 10, 11:48 AM posted to sci.space.tech
Michael Turner[_2_]
external usenet poster
 
Posts: 27
Default Technologies for Moon mission useable for missions further out

"Any colony on the Moon or Mars will have to deal with various sorts
of organic waste somehow. Composting it into soil is probably the best
solution."

Methane digesters would be better, especially if you're energy-
constrained. You could even burn the methane for low-level
illumination, not just space heating and cooking.

The heat input requirements for biogas reactors are a bit high,
perhaps, but this is a good use of solar heat and low-level process
heat; and production need not be continuous if you have a way to store
methane in some quantity. So you could wait for the sun -- even if,
on the Moon, that's a long wait and a lot of storage. The smaller
dead-end lava tubes have potential for large-scale gas storage.

You might increase the effective energy yield from the methane store
by sinking its heat into the surface geology and the sky during cold
periods, to chill it for higher compression, then exploiting the
greater temperature differential from daytime solar heat to drive
Stirling cycle generators. Chilling it is a good idea just from the
point of view of reducing storage requirements, though.

Achieving the needed gas mixtures for anaerobic bacteria wouldn't be
difficult in environments where there's only trace O2 to begin with.

But wouldn't you still want to compost stuff to fertilize your crops?
I don't think so. Biogas reactors can yield good fertilizer, sooner
than a compost heap. The whole process is not much different from
composting, actually, more of an acceleration of composting than a
diversion from it, with a very useful byproduct in the form of
methane.

Extraterrestrial colonization would have to develop to a fairly high
scale and high comfort level before these sorts of economies of
resource recycling would matter so little that people would resort to
composting. I think colonists would sell their own table scraps,
houseplant clippings and sewage to bioreactor operators as soon as a
colony had any kind of market economy at all. Not only would they get
a good price, they might *need* to get a good price -- in order to
afford to buy methane for heating, cooking and lighting. Walls and
ceilings of living spaces might be significantly taken up by greenery,
not just for aesthetics, to relieve stark living conditions, to grow
greens for salads, and to earn credits for CO2-O2 recycling, but also
to generate clippings for sale to methane & fertilizer producers. It
would be different on the Moon, running mostly on a two-week cycle
(expansion in the "morning", consolidation around "twilight") rather
than continuously and more stably, as on Mars. But many of the same
technologies and lifestyle adaptations would apply to Mars.

-michael turner

On Jun 19, 9:49 pm, Robert Heller wrote:
At Thu, 17 Jun 2010 23:15:06 EDT Alain Fournier w

rote:

Someone last year grew some plant in a Moon regolith imitation. It isn'

t
the most fertile soil but you can grow stuff in it. You then compost th

e
plants that grew in the regolith to have a fertile ground for farming.
So at first fertile soil would be in limited supply, but with time you
can make as much as you want.


Organic waste = soil. This is pretty much where 'fertile' soil on the
earth came from originally. Yes, it takes time. Any colony on the M

oon
or Mars will have to deal with various sorts of organic waste somehow.
Composting it into soil is probably the best solution.

--
Robert Heller -- Get the Deepwoods Software FireF

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  #19  
Old June 21st 10, 11:49 AM posted to sci.space.tech
Michael Turner[_2_]
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Posts: 27
Default Technologies for Moon mission useable for missions further out


"Someone last year grew some plant in a Moon regolith imitation. It
isn't the most fertile soil but you can grow stuff in it."

In the sense of providing support for roots and holding moisture,
perhaps. However, there seem to be qualitative differences between
lunar regolith simulant and real lunar regolith, none of them good:

http://www.lpi.usra.edu/decadal/leag/DavidJLoftus.pdf
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2193.pdf

To a reasonable first approximation, this stuff is nanometric silicon
oxide, subject to meteoritic and space-radiation processes that leave
the dust particles with lots more sharp edges -- at least when
compared to their terrestrial semi-analogues like official NASA lunar
regolith simulant. Nasty stuff you wouldn't want accumulating in your
lungs or wending its way through your GI tract.

This situation might argue for making your own dirt, by grinding up
rocks with less hazardous material and chemical properties. Grinding
up rocks to make soil? A waste of energy? Perhaps not. Maybe it
would just be a by-product of the sort of machining that would fall
right out of tunneling, and in general out of developing underground
habitat. Lava tubes are, of course, made by volcanic lava flows.
Volcanic processes produce rich soil on Earth. (The biggest carrot I
ever saw was at a market in the Aso-san caldera on Kyushu in Japan.)
Perhaps the Moon and Mars are much the same in this respect, they've
just never had plants taking any advantage of it.

-michael turner

On Jun 19, 9:49 pm, Robert Heller wrote:
At Thu, 17 Jun 2010 23:15:06 EDT Alain Fournier w

rote:

Someone last year grew some plant in a Moon regolith imitation. It isn'

t
the most fertile soil but you can grow stuff in it. You then compost th

e
plants that grew in the regolith to have a fertile ground for farming.
So at first fertile soil would be in limited supply, but with time you
can make as much as you want.


Organic waste = soil. This is pretty much where 'fertile' soil on the
earth came from originally. Yes, it takes time. Any colony on the M

oon
or Mars will have to deal with various sorts of organic waste somehow.
Composting it into soil is probably the best solution.

--
Robert Heller -- Get the Deepwoods Software FireF

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  #20  
Old June 21st 10, 10:01 PM posted to sci.space.tech
Robert Heller
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Posts: 17
Default Technologies for Moon mission useable for missions further out

At Mon, 21 Jun 2010 06:48:56 EDT Michael Turner wrote:


"Any colony on the Moon or Mars will have to deal with various sorts
of organic waste somehow. Composting it into soil is probably the best
solution."

Methane digesters would be better, especially if you're energy-
constrained. You could even burn the methane for low-level
illumination, not just space heating and cooking.


A methane digester also produces 'soil' (or at least the wherewithall
to produce soil) Once the carbon and hydrogen is extracted as methane,
the remaining solid matter and nitrogen is available for fertlizer.


The heat input requirements for biogas reactors are a bit high,
perhaps, but this is a good use of solar heat and low-level process
heat; and production need not be continuous if you have a way to store
methane in some quantity. So you could wait for the sun -- even if,
on the Moon, that's a long wait and a lot of storage. The smaller
dead-end lava tubes have potential for large-scale gas storage.

You might increase the effective energy yield from the methane store
by sinking its heat into the surface geology and the sky during cold
periods, to chill it for higher compression, then exploiting the
greater temperature differential from daytime solar heat to drive
Stirling cycle generators. Chilling it is a good idea just from the
point of view of reducing storage requirements, though.

Achieving the needed gas mixtures for anaerobic bacteria wouldn't be
difficult in environments where there's only trace O2 to begin with.

But wouldn't you still want to compost stuff to fertilize your crops?
I don't think so. Biogas reactors can yield good fertilizer, sooner
than a compost heap. The whole process is not much different from
composting, actually, more of an acceleration of composting than a
diversion from it, with a very useful byproduct in the form of
methane.


It might make sense to do a mixture and/or do different things with
different sorts of waste products. Eg kitchen waste (vegatable
trimmings, pea pods, etc.) might be composted rather then fed into the
biogas system. Toilets would feed the biogas system and 'grey' water
(typically washing waste water, with soap in it) will be processed
another way.


Extraterrestrial colonization would have to develop to a fairly high
scale and high comfort level before these sorts of economies of
resource recycling would matter so little that people would resort to
composting. I think colonists would sell their own table scraps,
houseplant clippings and sewage to bioreactor operators as soon as a
colony had any kind of market economy at all. Not only would they get
a good price, they might *need* to get a good price -- in order to
afford to buy methane for heating, cooking and lighting. Walls and
ceilings of living spaces might be significantly taken up by greenery,
not just for aesthetics, to relieve stark living conditions, to grow
greens for salads, and to earn credits for CO2-O2 recycling, but also
to generate clippings for sale to methane & fertilizer producers. It
would be different on the Moon, running mostly on a two-week cycle
(expansion in the "morning", consolidation around "twilight") rather
than continuously and more stably, as on Mars. But many of the same
technologies and lifestyle adaptations would apply to Mars.


Yes indeed!


-michael turner

On Jun 19, 9:49 pm, Robert Heller wrote:
At Thu, 17 Jun 2010 23:15:06 EDT Alain Fournier w

rote:

Someone last year grew some plant in a Moon regolith imitation. It isn'

t
the most fertile soil but you can grow stuff in it. You then compost th

e
plants that grew in the regolith to have a fertile ground for farming.
So at first fertile soil would be in limited supply, but with time you
can make as much as you want.


Organic waste = soil. This is pretty much where 'fertile' soil on the
earth came from originally. Yes, it takes time. Any colony on the M

oon
or Mars will have to deal with various sorts of organic waste somehow.
Composting it into soil is probably the best solution.

--
Robert Heller -- Get the Deepwoods Software FireF

ox Toolbar!
Deepwoods Software -- Linux Installation and Administratio

nhttp://www.deepsoft.com/ -- Web Hosting, with CGI and Database
-- Contract Programming: C/C++, Tcl/Tk




--
Robert Heller -- Get the Deepwoods Software FireFox Toolbar!
Deepwoods Software -- Linux Installation and Administration
http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
-- Contract Programming: C/C++, Tcl/Tk



 




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