Farming in space?

[too-open-minded]

wasn't too sure where to post this, I thought engineering complimented it best.

 

If we were to sustain life on a vessel in space, what would be the most practical method to feed ourselves? I would assume livestock be out of the picture. With resources at much less availability than on a celestial body and ventilation not as free as a biosphere, what would be the most practical method? Corn, roots, moss, maybe even chemically synthetic minerals? What would be the most efficient way to feed ourselves in space? Growing crops and harvesting them? Livestock?

 

 

[Greg H.]

For long term travel, growing crops in soil offers a couple of benefits, and a couple of drawbacks.

On the one hand, the human waste from the crew can be used to fertilize the plants, and the plants will help recycle the CO2 in the atmosphere back into breathable air. On the downside, all that dirt is HEAVY and you have to get it into space somehow, and then carry it around with you, which equates to additional fuel consumption. Finally, they would take up a LOT of space. You could stack smaller crops in trays to make better use of vertical space, but you're still going to be devoting a large part ofyour ship to what is, esentially, a backyard garden.

 

For short term travel, it's probably better to try and cram enough already processed food into the ship to last the trip. In the long run, the fuel costs in terms of added weight would most likely be less.

[Enthalpy]

No other biosphere than Earth has ever worked in the long term. The latest attempt I heard of, Biosphere 2, stopped after few seasons because carbon dioxide was out of control.

 

Obviously we know too little about life cycle to design a working biosphere. Crop growth efficiency is known, the rest is not.

 

How diverse must an ecosystem be to be sustainable even for few years? Unclear. And what's the minimum size to guarantee food despite natural variability of harvests?

 

The other aspect is that for few years, it's better to bring the food with the astronauts. In open loop, take 8kg per person a day; recycling air and water reduces it to 2-3kg. 2t soil per astronaut would be very little, but it takes already 3 years to justify.

[Endy0816]

I was thinking hydroponics for at least the vessel. Would mainly depend on space required and energy input, versus sending supplies on ahead of time. Would depend on the CO2 scrubber less and also save on dumping oxygen(locked up in CO2) overboard. Not exactly a lot of freely available oxygen where the ship is headed, so conservation could make more sense than replacement.

 

Long term colonization, would almost certainly require some form. At the very least it could serve as a backup to the backup of the backup. With a decent amount of processing could produce usable dirt from martian 'soil' and composting. That would make more sense instead of shipping it.

 

I was thinking chickens, cavies and insects would be some of the most probable options if livestock is desired. Obviously assorted plants and cultured meat could also work(for protien). Probably going to end up relying on a variety of sources rather than just one in particular.

Edited June 26, 2014 by Endy0816

[too-open-minded]

Thankyou y'all for the input! I think it's a really neat topic and something we as a species should seriously consider for the future.

[Greg H.]

No other biosphere than Earth has ever worked in the long term. The latest attempt I heard of, Biosphere 2, stopped after few seasons because carbon dioxide was out of control.

IIRC< that was due to the concrete flooring releasing CO² for some reason. I'd have to see if I can find that article again.

 

Edit

Wikipedia to the rescue.

Edited June 27, 2014 by Greg H.

[too-open-minded]

Here's what I think, for short term space travel. We could probably get away with cultivating crops. Nasa is working on this right now - http://www.nasa.gov/content/veggie-plant-growth-system-activated-on-international-space-station/#.U62wIfmuORU

 

However, for longer travels and even sustaining life on a vessel. I would think that with suspended animation to be necessary that we would need food that could last long periods of time. Something like cornsyrup and oils, However how hard would that be to cultivate crops then manufacture food with long shelf life?

Edited June 27, 2014 by too-open-minded

[Enthalpy]

Interesting! According to Wiki (thanks Greg H) the oxygen declined but the dioxide didn't increase as much because some concrete soil trapped it. And possibly, organics present initially in the soil to feed the growing plants used excessive oxygen as they were used by microbes instead.

 

From the Biosphere 2 observation, the answer to "how hard would it be" is just "we don't know how to do it".

 

Regenerate oxygen from dioxide is already done in space stations, the input being sunlight, then goinf through things like scrubbers, electricity and more. For instance a process uses a hot ceramic to electrolyze the dioxide. Recycle water is already done as well. I've suggested elsewhere to produce very simple food from waste water and dioxide by chemical means: glycerol is one candidate - but you can't feed a human only on that, it's just a sugar equivalent.

 

Storable food doesn't look very complicated. Seal, sterilize by radioactivity.

 

Some extraterrestrial soil has already proved to sustain plant growth. I don't remember if it was lunar soil brought back here, or terrestrial soil of the same composition as measured on Mars and sterilized - but anyway, plants accepted it.

 

If you need hundreds or thousands of tons of water, consider bringing an icy asteroid where needed, as I suggest there

http://www.scienceforums.net/topic/76627-solar-thermal-rocket/page-2#entry757109 updated

http://www.scienceforums.net/topic/76627-solar-thermal-rocket/page-2#entry757663

and anyway, the poles of Mars have water ice. Mercury as well, they say. Or grow plants on the asteroid where it is; do lichens grow on solid ice?

 

On Mars, the situation would differ a lot, because oxygen and dioxide can be an open cycle. Only water must be 100% recycled if not at the poles.

 

The real challenge in a closed vessel is to (1) recycle all the waste (2) produce fresh food - which goes together. I believe nobody has a justified solution to that. What we do on Earth has proven to fail in Biosphere 2; in an isolated space vessel, getting cockroaches instead of tomatoes wouldn't be surviveable. Maybe it demands microorganisms that we ignore, or impossible quantities just to guarantee enough diversity. If we sterilize everything to avoid unwanted species, we may well suppress unidentified vital ones.

 

Only further experimentation can tell. It doesn't need to be in space. Biosphere 3 and followers are the way to my opinion.

[renedascientist]

wasn't too sure where to post this, I thought engineering complimented it best.

 

If we were to sustain life on a vessel in space, what would be the most practical method to feed ourselves? I would assume livestock be out of the picture. With resources at much less availability than on a celestial body and ventilation not as free as a biosphere, what would be the most practical method? Corn, roots, moss, maybe even chemically synthetic minerals? What would be the most efficient way to feed ourselves in space? Growing crops and harvesting them? Livestock?

 

 

how about micro propagation? growing various vegetation in vitro. growing plants in this manner results in a faster growth rate, which is pretty important in space. you do not want to wait 4 months for strawberries to grow, when the same strawberries can grow from explant samples to fully hardened plantlets in just 3 weeks.

http://www.academia.edu/4363667/Micropropagation_of_strawberry_cultivar_Sweet_Charlie_via_axillary_shoot_proliferation

[fiveworlds]

Rice and potatoes http://en.wikipedia.org/wiki/Staple_food

Edited August 28, 2014 by fiveworlds