
Inside NASA’s Space Farming Labs - dsr12
https://motherboard.vice.com/en_us/article/inside-nasas-space-farming-labs
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mtchtrnr
I was part of the USU team mentioned in the article. There are a lot of
variables to take into account when growing plants in micgrogravity:

Particulates, like soil, are actually considered a hazardous material in space
because it can float into and clog up the ventilation.

Capillary action is a dominant force in microgravity and water will coat
everything.

Roots are respiratory and will absorb the oxygen in the water around them, but
the bubbles of CO2 they create won't naturally rise to the surface. This can
cause the roots to suffocate.

Hydroponics are the logical route because regular soil will deplete its
nutrient supply, but you still need a root growth substrate. The current
"Veggie" system uses vermiculite clay chips contained in a pouch. They had to
use the right gauge of particle diameter though: too small and it will
saturate with water and suffocate the roots, too big and there won't be enough
pressure gradient from the capillary action and the roots will dry out. Also,
if you don't have your hydroponic nutrient solution just right, salts will
build up in your substrate, so the pouches are typically single use.

Our team developed a method for 3D printing a growth substrate. This
eliminates the problem with particulates and it also allows you control the
gauge of the holes in the material to get the right air/water ratio. You can
even vary the hole sizes so the water is pulled by the capillary action more
at the dry end and fills the medium more evenly with water. It's not a perfect
solution. The hydrophilic nylon filament we used liked to warp when it was
printed. It also doesn't work for root vegetables like potatoes and stuff.
However, it is reusable, cleanable, recyclable, scalable, largely passive, and
safe. Plus, everyone loves 3D printers.

TL;DR Microgravity creates a lot of problems for growing plants in space, many
of which aren't immediately obvious. 3D printed growth mediums might be a
solution.

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sfifs
Serious question. Given all the difficulties with impact of microgravity on
human beings and in this case plant cultivation, why isn't there more serious
research/testing of generating artificial gravity through rotation? We only
seem to see that in science fiction, never in real life.

~~~
mtchtrnr
Well, for humans it's because you'd need a really big ring to make it actually
feel right. If the ring is too small, the difference in outward force created
in your head and your feet will be different enough that your blood will rush
to your feet and make you pass out.

For the most part, your garden variety of plants wouldn't be affected too much
by the force gradient. There actually has been quite a bit of research put
into this. I'm trying to find a source for this, but a few years back the
Japanese burned a bunch money on this kind of research and didn't end up with
anything substantial. If you do it on a smaller scale, just for the plants, it
also creates the issue of extra angular momentum added to your spacecraft.
This is manageable, but definitely something to take into account.

But, you're right. If you created gravity on a scale large enough for humans,
it would definitely get rid of most of the problems for the plants.

~~~
nickparker
Have you seen any literature on very low gravity rotary setups? Like <0.1g?

In the context of this thread, I'm mostly interested because it seems like a
happy middle ground to solve your capillary action issues. However it would
also be super interesting to see how a small acceleration like that could help
with e.g. retinal problems from microgravity.

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junipergreen
The blogs of the scientists who lived on fake Mars for a year in Hawaii make
it clear how important food is for astronaut's mental health as well as
physical nutritional needs: [https://walking-on-red-
dust.com/2016/06/18/domemade-food/](https://walking-on-red-
dust.com/2016/06/18/domemade-food/)

~~~
sampo
A couple of years ago I listened to a talk by a plant scientist from Florida.
They had some experiments, seedlings growing in the International Space
Station. Every day one of the astronauts took photos of the seedlings, to
document growth. He said that it was more or less everyone's favorite task in
the space station. "Today I get to look at the plants", the astronauts would
say.

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schwarze_pest
There is an aerospace engineer (ex NASA or Air Force IIRC) who youtubes the
science he does in his backyard:
[https://www.youtube.com/channel/UCd8t8Dq8oZeAjGDx_87azBw](https://www.youtube.com/channel/UCd8t8Dq8oZeAjGDx_87azBw)

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Ninjalicious
I see more metal than dirt in all of their experiments. No biohazard markers
anywhere so probably not using waste.

The best way to farm in space is to convert human waste into manure and
compost, and you need to have other organisms to do that. I don't see red
worms either.

NASA won't be able to engineer plants in space, it will have to adopt a
microbiome that exists on earth already that can be modularized into a
spacecraft. Growing lettuce is a joke, you need to figure out how to make pigs
and chickens into astronauts.

I'm not joking.

~~~
Cthulhu_
Indeed; even if they can make lettuce grow, it's very low in nutritional value
so they'd need to sacrifice a lot of space and energy into creating something
edible. Potatoes would work better. Space pigs, too, but they'd require a lot
of nutrients to keep alive and grow. iirc they need ten times as much food
than what their meat is worth in nutritional value.

The future is probably artificially produced food, like the porridge / sludge
shown in the Matrix. Something out of a chemical process instead of a
biological one.

~~~
Pfhreak
Potatoes are an interesting case, but they require rooting around through soil
to harvest. (Having grown potatoes in my garden last year, it was a much
messier endeavor than my greens.)

I'm not sure we're ready for all that soil to be floating around in the ISS,
literally mucking things up. Not saying it isn't possible, but why not use
lettuces to solve all the 'simple' problems about growing things in space
first.

Also, don't discount the quality of life improvement of eating some fresh
lettuce.

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eutectic
Aeroponics or hydroponics would help eliminate the mess issue.

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jelliclesfarm
I don't understand why we have to try and grow earth food plants in space? I
don't even get it. We can't even grow food crops of tropical climes in
America. Also Lettuce is not really a 'food' calories or nutrient wise. I
don't get it.

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imaginenore
Why do they even need soil? Aeroponics is way more efficient.

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openasocket
Interesting quote: "In microgravity, your taste sensation is dulled." I
haven't heard that before: anyone know why that is?

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takingflac
It has to do with the mucus in the nasal cavity not draining properly do to
the lack of gravity. Most of your sense of taste is actually due to smell
which is reduced when you have a stuffy nose. There are probably other
contributing factors, but this is one I remember hearing.

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CodeSheikh
These are some very EXPENSIVE organic veggies.

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dekhn
Wait, why do we send people to space in the first place?

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M_Grey
[https://www.ncbi.nlm.nih.gov/pubmed/27721383](https://www.ncbi.nlm.nih.gov/pubmed/27721383)

Good question! The answer is that we know so little about surviving there for
any appreciable length of time (compared to a human lifespan), that most don't
understand the challenges. Meanwhile they're relative experts with the
problems faced by a terrestrial existence.

TL;DR The hydrogen is always redder in the other man's H-Alpha band.

~~~
dekhn
The paper you cited explained why we shouldn't send people to space, not why
we should.

