DU space/solar experts: Is it theoretically possible for a solar-powered...

[brush]

Last edited Sun Jun 13, 2021, 01:44 AM - Edit history (1)

encampment with water and oxygen generating equipment to sustain human life that could be periodically re-provisioned with supplies as the space station is?

[eppur_se_muova]

1. Water and oxygen "generating" ? Or recycling ?

The latter would seem to me to describe any version of space station yet launched, so that would suggest a "yes".

[brush]

4. Wonder why this hasn't been done as a test bed for a Mars encampment?

[eppur_se_muova]

8. Biosphere 2 was supposed to be that, but it ran into problems.

https://en.wikipedia.org/wiki/Biosphere_2

Technically, it appears they did meet part of their original goal.

[Hugh_Lebowski]

2. As long as water is one of those supplies, I would think so ...

You could purify urine with solar power but there's also the water in your breath, which would be much more complex to recover. It would be 'possible' but I think very challenging if your water supply was never supplemented.

[brush]

3. No way to generate water with compounds of hydrogen and oxygen?

[Hugh_Lebowski]

6. Well, sure ... I'd guess if you had a big hydrogen tank and a big oxygen tank

aboard, one could construct water that way. Still would effectively need to resupply 'water' at least in terms of the two elements that make it up

[VMA131Marine]

7. Moisture in the air is easily recovered by cooling the air below the dew point.

This is one of the standard principles of modern air conditioning, which cools and dehumidifies air.

[Hugh_Lebowski]

10. Okay well we haven't discussed the total size of your 'ship' or whether you're wearing a helmet

at all times ... if the ship was relatively small and/or you wear a helmet such that all the water could easily be captured and recycled in this fashion, then yes I agree.

If the area you're 'living in' is relatively large, then you better start off with a significant overabundance of water, otherwise you could find yourself in need of water (perhaps through exertion) at a time where there's also significant condensation on the surfaces of your environment rather than existing as vapor from which you could condense a supply in the fashion you mention at a time of need

[Salviati]

9. The water you would breath out needs to be recondensed...

... otherwise the humidity would build up to 100% and it would start condensing on everything. They do condense it and recycle it back into the regular water supply on the ISS.

https://letstalkscience.ca/educational-resources/backgrounders/humidity-on-earth-and-on-iss

[Hugh_Lebowski]

11. See my post #10 :)

If you start off with a properly calculated amount of 'extra' water then I agree, it's possible to not need any additional water input.

[Salviati]

17. I guess I'm not sure what you're arguing...

You seem to be saying that if you have enough extra water, then you wouldn't need to recondense the water from the environment, but rather, I'd argue that whether you need the water for drinking or not, you need to recondense the water from the environment to maintain the suitability of the environment. If there is any open water in the environment, then over time the humidity will increase to 100% unless you take active measures to recondense the water.

On some level, the recondensing is a separate issue from the reusability of the water. Even if the recaptured water was somehow rendered non-potable, it would still be important to remove it from the air, to keep it from causing problems in your habitat, recycling the water for re-use is just a bonus. It's not an extra thing that you could do if it weren't too hard, it's something that you have to do, if you want to keep your habitat in good operating shape for a decent period of time.

[Hugh_Lebowski]

19. I'm just saying that you're right, the goal can be achieved with a closed-loop system for the water

but depending on the size of the living space and number of people and some other factors, I don't think you can just fly up without any additional clean water supplies.

You'd need a initial 'cushion' supply to account for the possibility that water condenses on surfaces and hence is not readily condensable for drinking at a time people need it. I believe water molecules can stick to 'things' without 100% humidity.

And yes if you had enough cushion, you wouldn't 'have to' condense the water from the air for drinking, but there's no reason you would not that I can imagine. As you said you have to condense it anyway, so what else would you do with it?

[Hugh_Lebowski]

20. Also, out of curiosity ... how does the ISS recycle the water from everyone's poop? (nt)

[Salviati]

21. That might be part of the 7% that they don't recapture...

This link talks about the process that they go through to distill liquid waste, I imagine that you could do something similar with solid waste, but perhaps they have decided that there's not enough to recover. I hadn't thought of the problems of trying to distill in zero-g before though, so that adds a layer of complexity to the recycling aspect.

https://www.nasa.gov/mission_pages/station/behindscenes/waterrecycler.html

[Shermann]

22. Easy!

[VMA131Marine]

5. Yes, it's possible and likely more than theoretically so

Water can be recovered and recycled, as it is on the International Space Station. Oxygen gets turned into CO2 by the human metabolism, but can be recovered from CO2 by plant photosynthesis and artificial means. Even essential minerals like phosphates can be recycled from waste. There could be some cycles that are not completely closed and thus need replenishment from time to time but this should not be a problem if the energy is available.

[WarGamer]

12. Don't forget about radiation and long term effects of low gravity

[LunaSea]

13. No place like Spome

https://en.wikipedia.org/wiki/Spome

See also:
https://en.wikipedia.org/wiki/Closed_ecological_system

You'd need a certain threshold of kilowatt power, and the more kilowatts available, the more you could do.
You can make a meal from a cubic meter of lunar regolith with enough power and facilities to work the materials.

We'll see some robotic missions in the very near future that will seek out and pioneer such resources and explore techniques with lunar ice and other volatiles.

[hunter]

14. Here you go...

https://en.wikipedia.org/wiki/Sabatier_reaction#International_Space_Station_life_support

A closed cycle, one that doesn't discard carbon or hydrogen, might be accomplished by photosynthesis. Plants turn solar energy, carbon dioxide, and water into oxygen and food. In turn, humans turn oxygen and food into carbon dioxide and water.

Another possibility would be genetically engineered bacteria that could do something similar to photosynthesis using electricity. Currently most of this research is aimed at making fuels, not food.

https://www.osti.gov/doepatents/biblio/1330696

[Buckeye_Democrat]

15. Do you mean something like a Mars colony?

Nuclear power would be far more preferable there.

Here's a video that mentions power issues near the beginning of it, before it delves into a large number of other problems that would need addressed.

[Hugh_Lebowski]

16. The ending narration makes me laugh cuz it literally sounds like the stupidest plan I've ever heard

as it goes along ... but then the narrator tries to make it sound like it's brilliant.

It's fucking ridiculous, flat out.

[Buckeye_Democrat]

18. Oh, trust me, I agree!

I consider it a monumental waste of time and resources.