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-   -   Aerogel martian habitats. (http://forums.sjgames.com/showthread.php?t=164568)

Anthony 07-15-2019 05:10 PM

Aerogel martian habitats.
 
Huh. Well, NASA recently poured cold water on Martian terraforming (there apparently isn't enough CO2 remaining to actually heat up the planet), but now they have another study about aerogel greenhouse habitats, which is neat to me because aerogel was a hot thing for a few years when I was a teen, then pretty much disappeared (it's still in use, just no-one gets excited about it).

Taneli 07-25-2019 05:34 AM

Re: Aerogel martian habitats.
 
IMNAE, so dunno, but would that be more feasible than having two sheets of glass (or something) with vacuum in there between?

Anyway, nice that people are thinking about domes. Maybe in my lifetime.

Astromancer 07-30-2019 12:43 AM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by Anthony (Post 2274273)
Huh. Well, NASA recently poured cold water on Martian terraforming (there apparently isn't enough CO2 remaining to actually heat up the planet), but now they have another study about aerogel greenhouse habitats, which is neat to me because aerogel was a hot thing for a few years when I was a teen, then pretty much disappeared (it's still in use, just no-one gets excited about it).

If there isn't enough CO2 on Mars proper, is there some frozen carbon dioxide somewhere in the outer solar system that we could haul to Mars?

Anthony 07-30-2019 01:57 AM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by Astromancer (Post 2276587)
If there isn't enough CO2 on Mars proper, is there some frozen carbon dioxide somewhere in the outer solar system that we could haul to Mars?

Sufficient cometary bombardment would add everything needed, but the scale involved is ridiculous and it would do an awful lot of damage to Mars.

Anaraxes 07-30-2019 09:27 AM

Re: Aerogel martian habitats.
 
Might as well condense Venus' atmosphere and transport that to Mars. Two terraformings for the price of one.

Comets are around 5% CO2. At least you want the water, too. If I'm reading the paper right, you need 3.6e18 tons of CO2 for a 1 bar atmosphere -- enough to allow liquid water. Halley's comet masses 2.2e14 kg, and at a quick glance seems not terribly atypical. That means 15,000 comets slamming into the surface, if they were pure CO2, or if we can count the water and CO in the atmosphere. Or just multiply by 20 to stick with that 5% number. If we can divert 15,000 comets into Mars, we can divert 300,000. On the bright side, you won't have to worry about those elaborate clean-room procedures to avoid space probes contaminating the surface with Earthly life.

Maybe processing the entire surface of Mars to a depth of 200 meters to decompose all the carbonate minerals isn't such a bad plan after all. Nanobots, self-assemble!

Here's a link to the paper at Colorado, and thus not behind the Nature paywall linked in the NASA article.

Anthony 07-30-2019 11:15 AM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by Anaraxes (Post 2276622)
Might as well condense Venus' atmosphere and transport that to Mars. Two terraformings for the price of one.

Comets are around 5% CO2. At least you want the water, too. If I'm reading the paper right, you need 3.6e18 tons of CO2 for a 1 bar atmosphere

You can turn water into oxygen too (and the hydrogen will escape fast enough), and on the scale we're looking at it isn't all that much more difficult than converting CO2.

Assuming the comets are hitting Mars at 10 km/sec (about the low end of velocities for a transfer orbit from the Kuiper belt), and our total mass is about 100 tons per square meter (of which about 30 turns into atmosphere) the total is 5e+12J/m^2. If you keep the temperature low enough for liquid water, you can eliminate heat at maybe 250W/m^2, more if you put up a sun shade. This gives a time to eliminate the waste heat of our collision product of 2e+10s or 634 years. That's super fast by geological standards, and honestly we'll probably need a lot more mass because of losses and reactions with the chemistry of Mars.

thrash 07-31-2019 08:13 AM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by Anaraxes (Post 2276622)
Here's a link to the paper at Colorado, and thus not behind the Nature paywall linked in the NASA article.

Quote:

Originally Posted by Janosky and Edwards 2018
Below we will discuss the amount of CO2 necessary to raise temperatures sufficiently to allow liquid water; for now, however, take a nominal requirement as being about 1 bar of CO2,

I'm not sure why they chose to explain it this way, rather than referring to a phase diagram directly. At the 20 millibars they estimate for total mobilizable CO2, liquid water can exist in the range of 273-293 K. This still probably isn't achievable with the terraforming technology we can envision, but it's much closer to possible.

Anthony 07-31-2019 11:07 AM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by thrash (Post 2276793)
I'm not sure why they chose to explain it this way, rather than referring to a phase diagram directly. At the 20 millibars they estimate for total mobilizable CO2, liquid water can exist in the range of 273-293 K. This still probably isn't achievable with the terraforming technology we can envision, but it's much closer to possible.

I think they wanted 1 bar so the surface temperature would reach 273K, not so the water wouldn't evaporate.

Prince Charon 07-31-2019 01:32 PM

Re: Aerogel martian habitats.
 
Quote:

Originally Posted by Anaraxes (Post 2276622)
Might as well condense Venus' atmosphere and transport that to Mars. Two terraformings for the price of one.

Stick one end of a wormhole in Venus's atmosphere, and the other end in the atmosphere of Mars, and you're in business - if you have the tech to pull that off, anyway. Was thinking of using that in a psi-tech setting, but it would be much harder to justify in TS.

Of course, given the pressures on Venus, you may need another place to dump the excess, once Mars is full, but you could also close the wormholes (save for transportation purposes), and use modified extremophile bacteria to precipitate more of the atmosphere to Venus's surface (which is well-within TS-tech's capabilities, and I think might be canon).

Shipping Venus's atmosphere to Mars using canon TS spacecraft would be rather expensive, to say the least.

doctorevilbrain 07-31-2019 01:35 PM

Re: Aerogel martian habitats.
 
What about getting rid of the sulfuric clouds?


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