Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Jimmy]

You don't necessarily need to rely on asteroids for H2O needs, since plenty of sources exist in the outer planet areas. Send drones to the rings of Saturn, programmed to drill large ice bodies and achieve escape velocity by conversion of water into steam as a source of propulsion. Rinse and repeat (no pun intended).

[Rolepgeek]

Real quick, I'm just gonna point out, almost by necessity, if you had enough plants to feed the people on that colony, you'd have enough plants to give them air to breathe, due to the way stoichiometry, biology, and the semi-reversible reactions of photosynthesis and cellular respiration.

[Tack]

Plant enough to breathe is a pretty farfetched concept seeing as most oxygen generation is due to phytoplankton and such.

[chaotic skies]

Yes, but that's also covering for billions of people and possibly trillions of animals. We only need enough plants for less than 10000 people, which is much more feasible.

[Amperzand]

Again, the big deal is CO2 scrubbing, not having enough oxygen effectively means you also don't have water, in a system with proper infrastructure. Plants turn CO2, a major problem, into O2, an important need. Probably not generally the best idea to rely on them entirely, though.

[chaotic skies]

I would never rely entirely on them. If anything, I'd focus on chemical scrubbers, with tanks for extra/back-up oxygen and use plants as an emergency thing.

[Amperzand]

A major question is whether chemical scrubbers are reusable. If they're disposable and need to be shipped in from industrial sites, it might be worth avoiding them to reduce orbital-shipping costs.

[Culise]

A major question is whether chemical scrubbers are reusable. If they're disposable and need to be shipped in from industrial sites, it might be worth avoiding them to reduce orbital-shipping costs.

Depends on the scrubber.  Some are reversible, others are not.  The last RCRS used on the space shuttle orbiters, for instance, was a regenerative system that used amines (HS-X, apparently) to absorb carbon dioxide, and could then reverse the process to release the CO₂ to vacuum, allowing them to be reused.  With that upgrade, carbon dioxide filtration was no longer, as far as I can tell, a limiting factor in shuttle mission lengths.

As for actually using the carbon dioxide (as just tossing it into the atmosphere would seem to be somewhat counterproductive on Venus, especially if you're trying to terraform it), the Sabatier reaction mentioned earlier in the thread would use your carbon dioxide and hydrogen, requiring energy, and output methane and water.  You can then electrolyze the water for more hydrogen and oxygen, and the CO₂ would come from ordinary respiration.  The only catch then becomes a 50% drop in molecular hydrogen (8 hydrogen atoms in, but you'll only get 4 back from electrolysis because the remaining 4 are bound up in the methane atom, which is arguably just as problematic to release), but the presently-theoretical Bosch reaction can break up the methane into elemental carbon and the rest of your hydrogen.  The biggest issue with a Bosch reactor is keeping a stable temperature of 600°C and dealing with any fouling from the carbon that would occur.

[Rolepgeek]

Plant enough to breathe is a pretty farfetched concept seeing as most oxygen generation is due to phytoplankton and such.

And most oxygen consumption is from non-human animals, fungi, bacteria, and so on. We use up oxygen in direct proportion to the amount of carbohydrates, proteins, &etc. we process for energy, give or take to account for gut bacteria. Plants produce oxygen in direct proportion to the amount of carbohydrates they make via photosynthesis. If you have enough plants to feed yourself, then those plants, in order to create the fruits or vegetable matter which you're going to eat, produce oxygen equal in proportion to the food they produce+their growth of non-edible plant material. Now, mind, bacteria in the soil and possibly losses from them using those carbohydrates to build other molecules and thus using up oxygen in that metabolic reaction is a consideration, and I'm not certain how much that would take up, but before that even becomes relevant, the size of potted plants that he was talking about, and garden plants, seems likely to be different, and most sources I found in a very simple google search said about 20L/hr for oxygen consumption.

[Amperzand]

A major question is whether chemical scrubbers are reusable. If they're disposable and need to be shipped in from industrial sites, it might be worth avoiding them to reduce orbital-shipping costs.

Depends on the scrubber.  Some are reversible, others are not.  The last RCRS used on the space shuttle orbiters, for instance, was a regenerative system that used amines (HS-X, apparently) to absorb carbon dioxide, and could then reverse the process to release the CO₂ to vacuum, allowing them to be reused.  With that upgrade, carbon dioxide filtration was no longer, as far as I can tell, a limiting factor in shuttle mission lengths.

As for actually using the carbon dioxide (as just tossing it into the atmosphere would seem to be somewhat counterproductive on Venus, especially if you're trying to terraform it), the Sabatier reaction mentioned earlier in the thread would use your carbon dioxide and hydrogen, requiring energy, and output methane and water.  You can then electrolyze the water for more hydrogen and oxygen, and the CO₂ would come from ordinary respiration.  The only catch then becomes a 50% drop in molecular hydrogen (8 hydrogen atoms in, but you'll only get 4 back from electrolysis because the remaining 4 are bound up in the methane atom, which is arguably just as problematic to release), but the presently-theoretical Bosch reaction can break up the methane into elemental carbon and the rest of your hydrogen.  The biggest issue with a Bosch reactor is keeping a stable temperature of 600°C and dealing with any fouling from the carbon that would occur.

AFAIK, you can use methane as fuel for combustion generators, though its outputs are likely a concern.

[Tack]

I was going to say that tubs of algae and brine shrimp would provide a better source (along with an alternate food source re:shrimp), but honestly I have no idea what the litres/day/M² would be.
Running water through the tanks could be a power sink, but at the same time if there's enough, they could help with liquid waste processing and maybe even allow for larger food animals in the enclosure.

Edit: plus if you keep them in the same area as your hydroponics (re:sun/sun lamps), you may actually get some evaporation and condensation.

[Culise]

AFAIK, you can use methane as fuel for combustion generators, though its outputs are likely a concern.

The inputs may be a concern as well.  You're combining methane and oxygen to create even more carbon dioxide, after all, which seems counterproductive for a system that's intended to convert carbon dioxide into oxygen. 

[Tack]

ARISE O THREAD. THROUGH THINE WILL I BIND THEE ONCE AGAIN TO CORPOREAL FORM TO CARRY THINE MESSAGE YONDER INTO THE DARKLING SKIES.

So had a thought recently about a country with a split-tier currency, one reserved entirely for necessities, one for luxuries and controlled substances. Feasibility? Either nowish or in space-sovia.

Had an amusing headclip of two executives complaining over a lobster dinner at how difficult it is to get protein bars on their salary.

[MonkeyHead]

ARISE O THREAD. THROUGH THINE WILL I BIND THEE ONCE AGAIN TO CORPOREAL FORM TO CARRY THINE MESSAGE YONDER INTO THE DARKLING SKIES.

So had a thought recently about a country with a split-tier currency, one reserved entirely for necessities, one for luxuries and controlled substances. Feasibility? Either nowish or in space-sovia.

Had an amusing headclip of two executives complaining over a lobster dinner at how difficult it is to get protein bars on their salary.

Not overly feasible, as there would inevitably be some kind of exchange mechanism between the two either directly or indirectly, rendering the whole thing rather pointless. 2 financial systems running in parallel would also have a huge redundancy issue. All in all, the drawbacks to me seem to outweigh the risks.

[GiglameshDespair]

Hmm... one could argue wartime rationing almost did introduce such a system, as some things were only available through ration books (e.g fuel) and could not be bought with money.

The real question is why such a system should be introduced, if there isn't something like a horrible grinding war ala ww2.