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Post by zachisajerk on Jun 28, 2017 22:33:36 GMT
It wouldn't be too difficult to feed and hydrate plants on a sizeable station. Especially if algae production is a factor, using it to feed fish and filtering out the waste to use in fertilizing plants. Once we have a system set up, everything from human waste to vegetable byproducts could be used in a cycle of furthering the growth of choice edible plants for consumption. As for the choice plants to grow,likely candidates would be soy beans, broccoli, mushrooms, spinach... plants that would yield produce what would give colonists vital nutrients.
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petrv
Space Pioneer
Posts: 93
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Post by petrv on Jun 28, 2017 23:33:02 GMT
regarding the "price" of water in space there are many attempts how to decrease the amount of water necessary for growing plants. I read some articles (will find later) where the water in hydroponics is replaced by mist (with dissolved nutrients), sprayed on plant´s roots instead of their´s submersion in water.
Hope bigred would add some practical/teoretical experience here?
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Post by zachisajerk on Jun 29, 2017 0:34:02 GMT
That's the best way to go about it. Often, people working with hydroponics will just continually have the same source of water running over the roots for a certain amount of time every so often, and keeping close attention to the pH, nitrogen, and other nutrient levels in the water to ensure the crops are gathering the right nutrients and at the right levels. The difference is, it'd be... not quite difficult, just more a burden to work with hydroponics and continually adding substances to keep the balance necessary for plant growth within the water being used... with aquaponics, more water is generally used due to the need for aquatic creatures, but their waste can be used to fertilize and feed the plants almost, if not entirely, on their own. It's more a debate regarding space and water used than anything... hydroponics would be smaller, likely would yield more, but require more care and attention to additives to the water supplied to them to ensure proper nutrients are allotted. With aquaponics, you'll need far more space and have to ensure the aquatic creatures (namely, fish) are well fed, but rarely would you need to add anything to the water supplied from the fish since it's already generally quite rich in the nutrients plants would need.
Both would require artificial lighting, but studies are being conducted and have been conducted regarding what light levels best work with what plants.
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Post by phicksur on Jun 29, 2017 14:09:05 GMT
Why not just plant them?
I mean, we are talking about having a lot of rocks from mining, and dirt is just tiny, tiny rocks mixed with organic matter. We could make our own dirt in space from mining debris.
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petrv
Space Pioneer
Posts: 93
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Post by petrv on Jun 29, 2017 23:32:22 GMT
IMO the soil = dirt & dust, which is not desirable in space habitat environment (not good for filters, airlocks, electronics etc.)
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Post by zachisajerk on Jun 30, 2017 1:25:32 GMT
Hydroponics and aquaponics are more space-efficient & far easier to maintain, given the nutrients they need are available. They tend to produce far more, as well.
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Post by phicksur on Jun 30, 2017 16:33:55 GMT
IMO the soil = dirt & dust, which is not desirable in space habitat environment (not good for filters, airlocks, electronics etc.) Only in zero-gravity. With centrifugal gravity, it actually makes more sense to grow them the same way we do on Earth.
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petrv
Space Pioneer
Posts: 93
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Post by petrv on Jun 30, 2017 23:03:12 GMT
That´s true, but in case of stopping of centrifugal movement (accident, service etc.) you have to deal with 0G...
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Mike
Space Pioneer
Posts: 82
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Post by Mike on Jul 1, 2017 16:00:58 GMT
It's hard to stop anything in space. Either meteorite would need to hit Space Station, or someone would have to turn engines for hours, for rotation to halt. And it would have to be done at certain angle, otherwise rotation would change direction, not stop. So... only heavy planning, and execution would do that.
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Post by bigred on Jul 7, 2017 1:52:27 GMT
hi all i'd like to take petrv's invitation and wade in with some of the stuff here....
The main problem with any growing system is the growing media environment. That means it has to remain in a balance which does not just include nutrient but many other aspects. The replenishment of nutrients is a big area as well.
Hydroponics: In hydroponics systems the same water cannot be utilised continuously due to build-ups of salts and mineralisation. Also, after a period of time the water itself appears to break down in it's ability to carry and deliver the nutrients in a manner conducive to optimum plant growth. This is the reason why the misting systems are in use - as the nutrients and active ingredients are mixed into the water at a point where it is being atomised. This utilises the water as a carrier rather than an absorbent delivery vehicle. ie. the force of the water and the suspension of the atomised materials in the atomised droplets delivers the materials to the plant. The plant reacts to the presence of water and so absorbs the materials it needs. It's a little more complicated than that but not much.
Soil: I cant answer most of the zero-G and filter questions however I can say that no matter what you do when humans are around there will be dust of all kinds so the filtration systems should be able to handle large particle dust such as are in soils without too much trouble. Also it would be prudent to have any soil environment in a separate compartmentalised area to avoid all sorts of issues related to soils, disease, fertilisation, evaporation etc. I would think that some form of non-airtight covering on the soil like a weedmat of some nature would hold it down in zero-G but obviously that theory would need testing...i'm pretty sure I wouldn't want a mouth full of "fertilised" soil when the spinning stopped :-) One of the main problems with an enclosed system is bio-waste management. Fortunately this can be solved by systems which actually turn bio-waste into usable growing media which doesn't require large amounts of moisture (due to the fact that the bio-waste already holds sufficient levels of moisture). Many systems have been tested and proven. The task would be to chose the most cost/energy/resource/safe/disease-controlled efficient system which sustains the growing media without the need for external-to-the-system nutrient replenishment. tbh using soil as a growing media is probably the absolute best way of controlling bio-waste in an enclosed environment as it controls disease and also contributes to solving the problems with sustainability of the food chain. As well, it requires no calculable human created energy input except a little muscle power.
The current thinking in the space industry is to dry bio-waste and extract the moisture for re-use then eject the dried media. This is not what is told to the kids at school on the NASA sites but it is what they do - you can trust me on that one as it was an area I worked with in designs for space-X. What people see on that movie about mars where matt damon gets everyone's dried shit from a bag is exactly correct. This is a wasteful and needless process which makes people think more about recovering the water as a liquid they see and thus psychologically can feel good about survival. This leads to the thinking that it is expensive waste to use water to supplement the sustainability of the food chain. The water within the bio-mass is there anyway and if the growing media is in balance does not need to be supplemented if it is not first extracted (an energy expensive process). The process of turning bio-mass into what we call soil fixes the problems that hydroponics and continued pumping of external water into the growing media and systems introduce. The water does not appear to break-down in its ability to absorb and deliver the materials the plants need for optimum growth and (in some systems) there is not a need to replenish the water in the system unless evaporation is taking place.
Algae: there are many uses for various types of algae. It is correct to surmise that there are algaes that are being developed for food chains. At this moment they are not so effective or (shall we say) palatable as we might think when a magazine screams "algae is the savior" as a headline. The thinking is that algae appears to grow easily in disparate and hostile environments and it is very hard to get rid of so surely it is perfect for solving food chain and energy problems. This may be true but there are some big difficulties. One of which is disease and the incompatibility of the environments needed for the algae growth to the environment necessary for optimum human living. Another is the amount of energy needed for growth is still at the same levels as that of normal plants. This is a generalisation however, a lot of the people pushing algae within and outside of the agronomy industry have the thinking that algae is like some sort of perpetual motion solution. They just see algae growing on the wall of a dirty shower and don't see how much energy is being put into the system or the problems surrounding that algae being in contact with humans. The algae which is OK for human consumption is of a very specific variety and to make it palatable it needs to be processed and refined and mixed with things like sugar or it tastes like chinese medicine :-) My partner who is a genetic researcher worked with some people in HK university looking into this and she feels it is a long way off due to the specificity of the algae required and the difficulties in keeping it clean of other harmful algal growth. It is very do-able however it is not what most companies are willing to put big money into. Having said that there are a lot of people having a go at it in a small way and there are a number of universities doing studies on it currently. There are also some medium size projects looking into algal fuel creation which are promising but use high levels of energy and money to create the refining factories/equipment/etc.
This is all standard knowledge and concepts from the industry. In my family's bio-tech company we do have a lot of specific knowledge about these systems and the tech to handle sustainable food chains in an enclosed environment. These have been and are still being tested with (mostly non-published) studies. However there are many projects around the world using this tech. The thing we haven't yet tested for (which will be tested this year in a project I'm managing) is the affects of high levels of radiation on the microbes used within our systems. This is necessary knowledge concerning growing anything in an enclosed system in space.
Hope that gives some perspective on a few items at least.
One thing I am personally curious about it the growing of fish in space. Our company has done quite a lot in the control and correction of bio-waste within the fish farming industry. The main problem is the bio-waste from the ponds tends to corrupt the surrounding environment when it is released. This is due to a number of factors but mainly the continued build up of waste materials which are toxic to the fish if not removed. This includes the water which follows the same problem path as that of hydroponics. However I'm interested in how they would grow and what would be the methodology. Generally fish grow quite fast and have very high levels of protein but there needs to be certain time frames and sizes and situations for regrowth/sustainability of the fish population to occur. eg. Salmon are very high in nutrients which humans can absorb but they need very specific areas, situations, and environments to breed. Also the size of the fish is very dependent on the size of the environment and the number of fish in that environment (pond). keeping the water in during zero-g would be interesting as well :-) fish would probably adapt to zero-g easily due to the viscosity of the environment they usually move and breath in not changing
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Mike
Space Pioneer
Posts: 82
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Post by Mike on Jul 9, 2017 12:11:38 GMT
Hydroponics: In hydroponics systems the same water cannot be utilised continuously due to build-ups of salts and mineralisation. Also, after a period of time the water itself appears to break down in it's ability to carry and deliver the nutrients in a manner conducive to optimum plant growth. Couldn't we just add this once used water into overall recycling procedure, so the "fresh" one will be used every time plant is watered? Yeah, I was thinking the same. If astronauts, during their journey to Mars, consume food, and produce errm... "waste", that wouldn't increase weight of ship. So couldn't we use this "poo" to make soil on Mars? Probably risky for consumed plants, but should be enough to grow grass. I haven't eat any of them, but I have read, that Japanese fishermen are consuming some sort of local algae for centuries. It doesn't have to be main energy source, but maybe can be used as additive? Couldn't that "toxic" water be used as fertilizer for plants? Maybe only for specific plants? I don't see problem with large glass aquarium balls. Water probably even don't spill, if it will be opened to catch fish. However I am not sure oxygen travels as it should, in 0G water. And if fish embryo can create spine (or whatever fish have), if there is no gravitation. Also, they could get disoriented, because on Earth, there is always surface, and fish can hunt for bugs, or plants up on it.
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