Space Ship based Hydroponics

[malloyd]

Originally Posted by Daigoro

After some homework, I found that most consumption rates are given in calories, which wasn't so helpful for what I was after. But Google does tell me that the average human consumes 1500lbs of food a year- I don't know how accurate or representative that is, but it's a useful starting figure.

Most foods are around 4 Calories per gram of dry weight, which would be about 400 lb/year for a subsistance diet. Counting water, undigestable cellulose and a more that subsistance diet 1500 lbs looks quite reasonable.

One of my sample SM+10 spaceships has 130 people on board, so using that and the figures in Spaceships on Open System sizes, I get-
Daily consumption of ~530lbs of food/day
Production per acre is ~2100lbs/day
Which is 480kgs/hectare/day for the metric-minded.

I'm no agriculturalist, but I suspect any modern day farmer would be ecstatic to get those sort of crop yields.

Depends on what you are comparing it to. It's fantastic for rain watered open fields (average grain crops run a couple tons per acre per year, somewhere around 2 kg/ha/day). On the other hand, commercial vegetable greenhouse economic calculations seem to be run at around 2.5 lb/square foot, which would be 335 kg/ha/day, which is a lot closer.

[vicky_molokh]

Originally Posted by sir_pudding

How does that even come up?
GURPS Bio-Tech definitely doesn't say this (and in fact discusses Selective Breeding, and even has a AH setting with a TL2 divergence point).

GURPS BIO does say it. But not everybody read it (and rightly so). Besides, I think I vaguely remember some roleplaying game which defines tech levels on one scale, and bio-tech-level on another, with the latter being equal to 1 where the general TL is somewhere in the 6-12 range (GURPS equivalent TL8-9).

[vicky_molokh]

Originally Posted by Ulzgoroth

There's this thing about English where you've got to accept that words mean different things in different contexts.

The word 'organic' means something quite different when talking about farming than when talking about chemistry. This is a feature, not a bug.

It might not be a bug, but it's certainly bad design. Would you ever want a word to have several very different meanings in the same context (I'm saying this because farming does include cases where the difference between organic and mineral substances is relevant).

[lexington]

Originally Posted by vicky_molokh

It might not be a bug, but it's certainly bad design. Would you ever want a word to have several very different meanings in the same context (I'm saying this because farming does include cases where the difference between organic and mineral substances is relevant).

All the foods you eat are organic in the sense used by chemists. Not all foods are organic in the sense used by farmers. So when someone says a food is organic you cannot seriously claim to be confused.

[vicky_molokh]

Originally Posted by lexington

All the foods you eat are organic in the sense used by chemists. Not all foods are organic in the sense used by farmers. So when someone says a food is organic you cannot seriously claim to be confused.

I can [avoid being confused], if I drop logic and start applying all the silly exceptions such bad design results in. For instance, you eat NaCl; it isn't organic. So saying you eat a non-organic chicken implies that it is made of salt or some other mineral substance.

(Edited, because the original post had me somehow saying things backwards.)

[lexington]

Originally Posted by vicky_molokh

I can, if I drop logic and start applying all the silly exceptions such bad design results in. For instance, you eat NaCl; it isn't organic. So saying you eat a non-organic chicken implies that it is made of salt or some other mineral substance.

I'm not sure I'd count salt on its own as a food. When you have to abandon logic to find a problem with something that's a good sign that you aren't dealing with a valid problem.

[Running Wolf]

yeah there would be a huge difference between some "organic chemistry" compounds and "organic food".

Remember the email spam that was going around a few years ago about margarine being one molecule off from plastic? Hydrogen peroxide is one molecule off from water, so the claim in the email was B.S.

The main thing I would think of supplying food on a space ship would be meat. You'd have to feed a cow or a pig (or any animal) food stuffs that could be used by people for their own bellies.

Having a supply of protein might be a problem. In a way I could see a crew of ship having to have a vegan diet.... not out of some morality or idealism but because of the food animals taking up life support systems and food. Beans and things like hemp seeds can provide some protein but you'd still need some sort of supplements to make up for the missing protein.

The idea of aquaculture might have some merits. Fish with some algae would serve a two fold purpose. Have the protein from the fish and the algae would provide water filtration as well as giving off some supplemental O2. the bio-mass of composting the algae might provide some methane to use in the directional thrusters of the ship as well.

[vicky_molokh]

Originally Posted by lexington

I'm not sure I'd count salt on its own as a food. When you have to abandon logic to find a problem with something that's a good sign that you aren't dealing with a valid problem.

No, I have to abandon logic to stop seeing a problem.

[lexington]

Originally Posted by Running Wolf

yeah there would be a huge difference between some "organic chemistry" compounds and "organic food".

Remember the email spam that was going around a few years ago about margarine being one molecule off from plastic? Hydrogen peroxide is one molecule off from water, so the claim in the email was B.S.

The main thing I would think of supplying food on a space ship would be meat. You'd have to feed a cow or a pig (or any animal) food stuffs that could be used by people for their own bellies.

Having a supply of protein might be a problem. In a way I could see a crew of ship having to have a vegan diet.... not out of some morality or idealism but because of the food animals taking up life support systems and food. Beans and things like hemp seeds can provide some protein but you'd still need some sort of supplements to make up for the missing protein.

The idea of aquaculture might have some merits. Fish with some algae would serve a two fold purpose. Have the protein from the fish and the algae would provide water filtration as well as giving off some supplemental O2. the bio-mass of composting the algae might provide some methane to use in the directional thrusters of the ship as well.

In the long term you might need a pretty complete ecosystem built into the ship. Fish. Worms. Plant crops. Fungal crops (mushrooms can supply some extra protein). Attendant bacterias. Water for all of them. Eggs and seeds in case too many die or need to be harvested. Maybe nutrients to keep plant yields high.

Of course that ends up being a lot of material to move around. If you're just going to Mars and back packing supplies is probably easier.

Optimistic assumptions about genetic engineering (both for foods and humans) would be a good way to slice those requirements down to manageable levels.

Originally Posted by vicky_molokh

No, I have to abandon logic to stop seeing a problem.

That's the exact opposite of what you said two posts ago. Seriously, scroll back up and look.

[vicky_molokh]

Originally Posted by lexington

That's the exact opposite of what you said two posts ago. Seriously, scroll back up and look.

Fixed. Count that as a major brainfart on my part.