Opcn

Opcn OP t1_j11n3wg wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

It's functionally 100%. It's not perfect, because every system leaks, but we are talking 2.5 milliliters per day loss from the ISS as unrecovered humidity.

Composting wouldn't be 100% efficient, but you go through 10-20 crop cycles and the amount of hydrogen locked into the recalcitrant residues is going to be measured in milligrams per kilogram of crop yield.

You keep declaring me stupid but NASA, ESA, CSA, ISRO, and CNSA are all still looking at this process and they absolutely aren't treating it as forgone stupid conclusion like you are. There are a lot of really brilliant and really well educated people who are looking really carefully at this, and building test systems on earth and in space.

What's the better explanation? That extremely well educated people from many different academic and industrial disciplines are all failing to notice the very basic considerations that you would expect an elementary school class to think of in a guided exercise, or that you haven't thought it through?

1

Opcn OP t1_j11gter wrote

Reply to comment by [deleted] in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

Composting the residues and eating the yields uses exactly as much oxygen as growing releases. And it releases exactly as much H20 and CO2 as growing consumed.

I'm not an idiot, and I've looked into this extensively. Stop treating me so poorly. Did you not notice that your last two abusive responses were over how I missed something that I clearly addressed in a previous comment?

1

Opcn OP t1_j11el0t wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

> Oh, so you eat the whole plant?

>Or are you just eating the “seeds” and leaving the rest of the plant?

>You do realize there is more plant left behind the when you harvest rice?

>Oh, that’s right, you are only eating a tiny section of the plant itself………..

" let's say 2 to 1 crop residue to yield (which is an overestimate but that more than makes up for the fact that a tiny percentage is going to be oils which take more water for a kilo of product) so that's 100 liters in the soil, 3.6 liters in dry matter"

>Yes you are ignoring the whole weight of the plant that is still carbohydrates, but we can’t digest.

>Or can you, amongst all humans, break down cellulose??? Oh you can’t…. Cool cool cool cool

"The crop residues are composted releasing the water, the food is eaten, releasing the water."

1

Opcn OP t1_j10gf46 wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

>You totally ignored the fact that you can’t recapture the water lost to carbohydrate production. You know sugars and cell walls and all that jazz…

No, I didn't ignore that. Each kilogram of carbohydrate takes ~600 grams of water. Guess how much water is released by the body when that carbohydrate is consumed and metabolized? 600 grams. So lets say you have 30cm of soil and a yield of 2kg per square meter maintained at 33% moisture by volume (a reasonable number and round to make the math easier) let's say 2 to 1 crop residue to yield (which is an overestimate but that more than makes up for the fact that a tiny percentage is going to be oils which take more water for a kilo of product) so that's 100 liters in the soil, 3.6 liters in dry matter and because the plant is living at some point say 2.5* the dry weight of yield and residues so 15liters. Add all that together and you've got 118.6 liters of water not counting the 25 ml of water per cubic meter that you can potentially have as humidity.

The 100 liters of water cycles through the air which is nearly 100% recycled. The crop residues are composted releasing the water, the food is eaten, releasing the water.

The two ways that the ISS loses most of its water are through air cycling (which the plants decrease the need for) and through disposal of poop (some of which may be composted with crop residue). At no point are thousands of liters of water going into every kilo. At no point do you need thousands of liters of water for every kilo that you want. Also, there is water in space, in comets, in lunar craters, buried in the martian regolith and frozen in the martian icecaps. There isn't a whole lot of food out there.

1

Opcn OP t1_j10bm2f wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

I am not agreeing with you that you need to send thousands of liters of water for every kilogram of rice you intend to grow. The vast majority of the water used in growing rice can be recycled. I backed that up with evidence. If you think I'm agreeing they you haven't bothered to understand the situation.

2

Opcn OP t1_j0zzov6 wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

> And you are over assuming what can be recaptured also.

My assumption is near 100% of the water not embodied in the macromolecules that make up the plant body. That assumption is based on historical precedent. The ISS currently recycles 90% of their water, but growing plants would decrease the water lost to the sabatier process and wouldn't increase the amount of water lost in the toilets. Growing food large scale on the ISS is impractical, but on a deep space long duration mission it won't necessarily be impractical.

2

Opcn OP t1_j0y05e9 wrote

Reply to comment by versuvius1 in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

Oh, this is different from using space to irradiate seeds. Though different bonds are impacted by ionizing radiation of different energy so it might be different than gamma radiation on earth. This rice was not just taken to space and brought back, that's happened before, this rice was taken to space, planted in space, grown in space, harvested in space, and brought back to earth.

4

Opcn OP t1_j0xzx95 wrote

Reply to comment by kslusherplantman in World's first rice seeds harvested in orbit onboard China Space Station return to Earth by Opcn

Most of that is transpired. In space that water is condensed back out of the air and is available to put back to use drinking, washing, or watering plants. You only need enough water to keep the air appropriately humid, provide the hydrogen fixed into carbohydrates, keep the plant tissue hydrated, and keep the soil appropriately moist. Everything beyond that is just recycled and held in a tank as a buffer.

8