Whetehr a Habitat will have rain from overhead pipes or from some
type of weather system, what will happen to the water that reaches
the ground?
bind with the soil. But some will also percolate through the soil
and go where? What mechanism will be in place to capture the water
that works its way through the soil and now approaches the pressure
shell?
Any thoughts?
TangoMan
Personally i think water from the overhead pipes is
wasteful. Some sort of drip system could be used for
greenhouses which could be coupled with sensors in the
soil to help determine the exact amounts of water
needed for growth.
colonies to take advantage of all technologies
available to make sure only the minimum amount water
that is needed to sustain plants is administered.
> Personally i think water from the overhead pipes is
> wasteful. Some sort of drip system could be used for
> greenhouses which could be coupled with sensors in the
> soil to help determine the exact amounts of water
> needed for growth.
TangoMan
> Some will evaporate. Some will be soaked up by biomatter. Some will
> bind with the soil. But some will also percolate through the soil
> and go where? What mechanism will be in place to capture the water
> that works its way through the soil and now approaches the pressure
> shell?
I would simply let the water form a "water sheet" between the soil and the
hull and pump it back to reservoir.
However, I think that hydroponics is more likely to be used, and in this case
water circulation is all controlled, anyway. Hydroponics is already
commercially used even on Earth, though in a very limited way. (And again I'm
considering my idea of hive-like habitats. :-)
> TangoMan
Lucio
Personally i think water from the overhead pipes is
wasteful. Some sort of drip system could be used for
greenhouses which could be coupled with sensors in the
soil to help determine the exact amounts of water
needed for growth. I think you're visualizing something different from what TangoMan is. I get the impression you're thinking about a space station with some associated greenhouses. I'm assuming TangoMan was asking about large O'Neill style space habitats, which in addition to crops would also have vast green fieldsand trees. Water is a scarce resource in space. This will drive
colonies to take advantage of all technologies
available to make sure only the minimum amount water
that is needed to sustain plants is administered. Water (or at leastthe hydrogen component of it) might be scarce in the early days of High Frontier, assuming that we start off with lunar resources first, and only transition to asteroidal resources later. But once we've tapped into asteroids, water shouldn't be significantly more precious than any other substance. But even when water is rather expensive to produce, don't forget that space habitats will have closed ecologies. Water used will not leave, but just cycle back through the environment. The cost of water will affect the cost of setting up a new habitat, but not necessarily the cost of using water once you're set up.
Mike Combs
> Water is a scarce resource in space. This will drive
> colonies to take advantage of all technologies
> available to make sure only the minimum amount water
> that is needed to sustain plants is administered.
is *very* abundant in space. Hydrogen is the most common element in the
universe, and oxygen is very abundant too, and as a result probably most of
the solid mass of the Universe is water ice. Look at the Solar System, for
instance: the combined ice of all existing comets in the Oort Cloud could be
used to form a planet ten times more massive than Earth. (According to a very
sketchy calculation that I have just done.)
However, I would agree that water is difficult to get in the Inner Solar
System (even carbonaceous asteroids will require a lot of processing for
water production, I think), and then your observation is valid for that
volume of space - the first one that we will colonize, by the way.
Lucio
>Even so, what happens to the water that percolates through the soil?
>
What happens on earth? It goes into a drain which goes down hill and
leads to a river. The river leads to a lake or a sea. Do the same thing
on a habitat and pump the water out of the lake, process/filter it, and
rain it back down again. Is this hard?
>
-Ian
"If you want to build a ship, don't drum up the workers to gather wood,
divide the work, and give orders. Instead, teach them to yearn for the
vast and endless sea." -Antoine de Saint-Exupery
> I think you're visualizing something different from
> what TangoMan is. I get
> the impression you're thinking about a space station
> with some associated
> greenhouses. I'm assuming TangoMan was asking about
> large O'Neill style
> space habitats, which in addition to crops would
> also have vast green fields
> and trees.
I was primarily thinking of greenhouses but the same
holds true fields. In southern california, many lawns
have sensors in them which help determine how much
watering is needed. Also, as this is a closed
systems, you could also use remote sensors to
determine the health of the fields similar to
something of a landsat's thermatic mapper
functionality and tie this into the water management
system.
is bet for a more contained growing system for crops.
> Water (or at least the hydrogen component of it)
> might be scarce in the
> early days of High Frontier, assuming that we start
> off with lunar resources
> first, and only transition to asteroidal resources
> later. But once we've
> tapped into asteroids, water shouldn't be
> significantly more precious than
> any other substance.
>
> But even when water is rather expensive to produce,
> don't forget that space
> habitats will have closed ecologies. Water used
> will not leave, but just
> cycle back through the environment. The cost of
> water will affect the cost
> of setting up a new habitat, but not necessarily the
> cost of using water
> once you're set up.
>
I am not optimistic that a true closed system could
ever retain all the water. Some water will be lost
eventually. How will a closed system collect water
excreted from sweat glands? Will we all be forced to
wear stilsuits (ala dune)? Will we drain the water
from dead people? When people leave the habitat, must
they leave behind all water?
Now I know hydrogen and oxygen exist throughout the
universe, (especially when you get out towards the
kuiper belt area) but I am not confident in the early
days of an o'niel habitat (those being the ones in the
inner solar system) that we will be able to take
advantage of those resources or be able to survive in
a true closed loop environment system.
Heck, we still haven't been able to successfully run a
closed-loop biosphere here on earth. much less in
space!
Ryan
> I am not optimistic that a true closed system could
> ever retain all the water. Some water will be lost
> eventually. How will a closed system collect water
> excreted from sweat glands? Will we all be forced to
> wear stilsuits (ala dune)? Will we drain the water
> from dead people? When people leave the habitat, must
> they leave behind all water?
the air can be cooled and become water again.
> Heck, we still haven't been able to successfully run a
> closed-loop biosphere here on earth. much less in
> space!
BTW, I can't agree that Earth *itself* is a closed ecosystem. It just "looks
like" a closed ecosystem due to two factors:
- The system is so big that perceivable changes take centuries at best to
occur, and whole geological ages in the general case.
- Input of new resources into the system is relatively so small that it is
often neglected and the system is assumed to be "homeostatic".
But, indeed, there *is* input in the Earth ecosystem. For instance, volcanoes
are always dumping significant amounts of CO2 (and other gases) into the
atmosphere; meteors and cosmic dust add thousands of tonnes of new matter
each year; and so on. Those inputs are so small compared to the system as a
whole that they are often neglected, but over geological time scales (the
time scale where the system changes) they do matter.
So, Earth looks like a closed ecosystem only in our limited human perception,
but in fact is is a system with continuous input. And therefore our efforts
to produce a small closed ecosystem, a "Biosphere 2", are a bit chimerical,
for in the first place it is trying to reproduce something that does not
really exist...
> Ryan
Lucio
--- In ssi_list@... Ian Woollard
>
> >Even so, what happens to the water that percolates through the
soil?
> >
> What happens on earth? It goes into a drain which goes down hill
and
> leads to a river. The river leads to a lake or a sea. Do the same
thing
> on a habitat and pump the water out of the lake, process/filter
it, and
> rain it back down again. Is this hard?
hill, joins a river, then to a lake. Other water percolates through
the ground until it hits impermeable rock, then flows along those
contours until it finds its way to a lake, or if the underground
contours prohibit water flow to a lake, the accumulated water
becomes an aquafer.
In a Habitat, the Island 3 variety, with the farming (traditional or
hydroponic, carried out elsewhere, the flora will need to be
sustained with water. If there is indeed some "natural" weather
system, then rain will occur. In the parts of the Habitat that are
urbanized, the rain will fall on rooftops, city streets, sidewalks,
etc, all impermeable, and that water can be channeled to drains,
sewer mains, lakes, etc.
How about the wter that falls on your lawn, rose garden, city parks,
etc? As I see it most will be evaporated or used by the flora, but
some will be excess, and I don't think we want to have a aquafer
accumulating against the pressure hull, do we?
So, do we line the dirt with those big plastic sheets that they now
use to line landfills. They're supposed to last for thousands of
years.
Or do we have a cast basalt liner around the interior of the Habitat
constructed in the form of many small peaks and valleys. The water
wouldn't be able to permeate the basalt liner, it would flow down
the slope to the valley bottom, where we could use pipes like they
use for septic fields, namely, ones that have holes in them to allow
the water to enter the pipe but not escape it. Then channel the flow
through a pipe system to a central reservoir.
Is this over-engineering the problem? Is this a problem at all?
Nevertheless, I do believe the solution has to be maintenance free
for the entire life of the Habitat because it may be difficult to
repair or maintain such a system when building will be built over
the surface thus prohibiting access.
Do you see a simpler way to replicate the water reclamation cycle?
TangoMan
Also, as this is a closed
systems, you could also use remote sensors to
determine the health of the fields similar to
something of a landsat's thermatic mapper
functionality and tie this into the water management
system. Oh, OK. Yeah, I could imagine some thermatic mapping going on much more easily than I could imagine a sensor under every tree, bush, or shrub in several square miles of countryside. I am not optimistic that a true closed system could
ever retain all the water. Some water will be lost
eventually. How will a closed system collect water
excreted from sweat glands? Will we all be forced to
wear stilsuits (ala dune)? Will we drain the water
from dead people? Where would the water go? Unless the habitat shell is a permeable membrane (which it shouldn't be) the water will still be inside the habitat, regardless of its location. It will be necessary to cool habitats with heat radiators, and these radiators will inevitably reclaim huge amounts of condensed water. This will be the water evaporated off the surfaces of ponds and streams, given off by plants via transpiration, and evaporated sweat (but that will be avery small percentage of the total). I doubt that any truly significant amounts of water would wind up "locked away" from the ecology in the form of dead bodies. But a person who had concerns about this might opt for a biodegradable casket, or better yet, cremation. When people leave the habitat, must
they leave behind all water? People will be entering and leaving the habitat all of the time. Those entering will bring a certain amount of water with them that they will leave behind. On the other hand, they'll take some other water with them when they leave. It'll come pretty close to balancing out. Now I know hydrogen and oxygen exist throughout the
universe, (especially when you get out towards the
kuiper belt area) but I am not confident in the early
days of an o'niel habitat (those being the ones in the
inner solar system) that we will be able to take
advantage of those resources or be able to survive in
a true closed loop environment system. You may not be aware that SSI has funded a bit of CLLSS work. They seem to consider the water cycle to be a pieceof cake compared to the nitrogen cycle. Heck, we still haven't been able to successfully run a
closed-loop biosphere here on earth. much less in
space! Don't get too discouraged by the failings of Biosphere II. Humanity's first few attempts at heavier-than-air flight were not successful either, and Biosphere II was the first significant, large-scale attempt.
Mike Combs
--- In ssi_list@... "victoriatangoman"
> --- In ssi_list@... Ian Woollard
> >
> > >Even so, what happens to the water that percolates through the
> soil?
> > >
> > What happens on earth? It goes into a drain which goes down hill
> and
> > leads to a river. The river leads to a lake or a sea. Do the same
> thing
> > on a habitat and pump the water out of the lake, process/filter
> it, and
> > rain it back down again. Is this hard?
>
> On Earth, some water stays near, or on, the surface, flows down
> hill, joins a river, then to a lake. Other water percolates through
> the ground until it hits impermeable rock, then flows along those
> contours until it finds its way to a lake, or if the underground
> contours prohibit water flow to a lake, the accumulated water
> becomes an aquafer.
>
> In a Habitat, the Island 3 variety, with the farming (traditional
or
> hydroponic, carried out elsewhere, the flora will need to be
> sustained with water. If there is indeed some "natural" weather
> system, then rain will occur. In the parts of the Habitat that are
> urbanized, the rain will fall on rooftops, city streets, sidewalks,
> etc, all impermeable, and that water can be channeled to drains,
> sewer mains, lakes, etc.
>
> How about the wter that falls on your lawn, rose garden, city
parks,
> etc? As I see it most will be evaporated or used by the flora, but
> some will be excess, and I don't think we want to have a aquafer
> accumulating against the pressure hull, do we?
>
> So, do we line the dirt with those big plastic sheets that they now
> use to line landfills. They're supposed to last for thousands of
> years.
>
> Or do we have a cast basalt liner around the interior of the
Habitat
> constructed in the form of many small peaks and valleys. The water
> wouldn't be able to permeate the basalt liner, it would flow down
> the slope to the valley bottom, where we could use pipes like they
> use for septic fields, namely, ones that have holes in them to
allow
> the water to enter the pipe but not escape it. Then channel the
flow
> through a pipe system to a central reservoir.
>
> Is this over-engineering the problem? Is this a problem at all?
>
> Nevertheless, I do believe the solution has to be maintenance free
> for the entire life of the Habitat because it may be difficult to
> repair or maintain such a system when building will be built over
> the surface thus prohibiting access.
>
> Do you see a simpler way to replicate the water reclamation cycle?
>
> TangoMan
should have a double wall so that maintenance personnel (or robots)
will have inspection access to the pressure hull. The double hull
(or Basalt layer as you described) could simply have a drain tile
that caries away water that has percolated though the dirt. This, of
course, only describes one segment of the water cycle on board. The
entire water cycle would need to be carefully engineered.
>
> Also, as this is a closed
> systems, you could also use remote sensors to
> determine the health of the fields similar to
> something of a landsat's thermatic mapper
> functionality and tie this into the water management
> system.
>
> Oh, OK. Yeah, I could imagine some thermatic mapping going on much
more
> easily than I could imagine a sensor under every tree, bush, or
shrub in
> several square miles of countryside.
>
> I am not optimistic that a true closed system could
> ever retain all the water. Some water will be lost
> eventually. How will a closed system collect water
> excreted from sweat glands? Will we all be forced to
> wear stilsuits (ala dune)? Will we drain the water
> from dead people?
>
> Where would the water go? Unless the habitat shell is a permeable
membrane
> (which it shouldn't be) the water will still be inside the habitat,
> regardless of its location.
>
> It will be necessary to cool habitats with heat radiators, and these
> radiators will inevitably reclaim huge amounts of condensed water.
This
> will be the water evaporated off the surfaces of ponds and streams,
given
> off by plants via transpiration, and evaporated sweat (but that
will be a
> very small percentage of the total). I doubt that any truly
significant
> amounts of water would wind up "locked away" from the ecology in
the form of
> dead bodies. But a person who had concerns about this might opt
for a
> biodegradable casket, or better yet, cremation.
>
> When people leave the habitat, must
> they leave behind all water?
>
> People will be entering and leaving the habitat all of the time.
Those
> entering will bring a certain amount of water with them that they
will leave
> behind. On the other hand, they'll take some other water with them
when
> they leave. It'll come pretty close to balancing out.
>
> Now I know hydrogen and oxygen exist throughout the
> universe, (especially when you get out towards the
> kuiper belt area) but I am not confident in the early
> days of an o'niel habitat (those being the ones in the
> inner solar system) that we will be able to take
> advantage of those resources or be able to survive in
> a true closed loop environment system.
>
> You may not be aware that SSI has funded a bit of CLLSS work. They
seem to
> consider the water cycle to be a piece of cake compared to the
nitrogen
> cycle.
>
> Heck, we still haven't been able to successfully run a
> closed-loop biosphere here on earth. much less in
> space!
>
> Don't get too discouraged by the failings of Biosphere II.
Humanity's first
> few attempts at heavier-than-air flight were not successful either,
and
> Biosphere II was the first significant, large-scale attempt.
>
> Regards,
>
> Mike Combs
to air and water, but with respect to people and commerce, they must
be open systems. I would suspect that there would be a continual
loss of volatiles over the life of the habitat. Air (and water) can
escape through airlocks leaks, accidental discharges and so-on.
But, there will be opportunities for pioneering businessmen to go out
to the belt and bring back frozen volatiles.
Keep in Mind the Biosphere was an attempt at a truly closed system,
and they were very close to succeeding at that. They could have used
some "less natural" techniques to reduce CO2 build-up, but they
wanted to use techniques that were "sustainable" and "organic". The
compost pile alone probably produced as much CO2 as two people.
Instead I would have recommended a box of miracle grow.
In regards to water percolation through soil:
I've heard from my Dad that the wheat farm of his Dad in Canada
in the late '40's used the tile system mentioned in a previous post.
Tile was dug in sloped to a large catch basin/ reservoir. The
heavy winter snow melt was caught as it percolated down through the soil
and reused for summer irrigation by pumping the same water back up the
same tile that was used for the run off.
I worked on an engineer project here in Portland back in the 70's
where a high school football field was converted to a much more efficient
method of grass maintenance. (Not to mention the removal of the 5 foot
elevation rise that ran down the middle of the entire length of the
field.)
Huge quantities of soil were removed and a liner was placed on
the bottom. Sloped channels leading to a main catch basin were placed.
There was at least 3 feet of sand placed over the liner. Pipe was placed
on top at normal irrigation levels. An initial supply of water was
placed and maintained in the main catch basin.
The turf layer was placed on top and the normal watering
procedures began. As the water percolated through the sand it would run
eventually back to the catch basin.
Later liquefied weed and feed was added to the catch basin to be
pumped to the grass via the normal watering process.
Seemed like a straight forward process. The field was still in
operation the last time I heard 10 years ago.
Steve Ivens