Writing Science Fiction Novel about living above Venus in the near Future! Need help with Science!

[Andrew Zachary Foreman]

5 minutes ago, KerikBalm said:

1) As mentioned before, the easiest way is just to condense it from the atmosphere. Luckily the water vapor is a lot easier to capture than the helium, even though both are in similar abundance (double digit parts per million)

Note that you don't "filter" gases like this. What you'd probably be doing is called "fractional distillation"

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

Its how we produce Xe from our atmosphere now, and its how you'd take the N2 out of the atmosphere as well. I suppose some chemical methods may work too (chemical methods won't work for noble gasses like Helium though)

Essentially, the gas condenses or freezes out at different temperatures. The CO2 will freeze out at -78 C, leaving a mixture that is mostly just nitrogen. I don't know if further purification would be neccessary. The Sulpher dioxide would condense out at this temperature as well, leaving just N2, some harmless inert gasses (Argon, Helium, Neon), and then theres the

HCl and HF... which are quite bad, but those combined are less than 0.7 ppm, so maybe it wouldn't be too bad... plus they're quite reactive so chemical purification should work. HF should condense to a liquid by -78C, and be easy to remove. HCl would unfortunately still be a gas. You could cool it down to -85 C to get that to liquify if the small amount of HCl is a problem and can't be removed by other means... The N2 won't liquify until -196 C, so you'll separate the components quite well by just cooling below -78 or -85C

Long before you cool it down to -78, the water will have condensed out. Cooling a million liters of venusian atmosphere will leave you with the equivalent of 20 liters of water vapor... this is the vapor... thats about 1 mol of water, or a measly 18 grams of it. You'd need to cool about 50 million liters of venusian atmosphere to get a liter of liquid water. You would need excellent water recyling. It doesn't sound so bad if you use cubic meters, then its only 50,000 cubic meters... Thats actually just a cube of 36.8 meters... Just cool it down and scrape the condensation of the sides, and repeat, you'll get almost a liter each time.

Run the "AC" constantly on air you suck in, and water will start condensing, just minimize losses, and you should be fine.

My guess is that they'd mostly "run the AC" for the purposes of water extraction, cooling air more to get the N2 would require much smaller volumes (as its 35,000 ppm compared to H2O at 20 ppm). The same equipment can get you the N2 and the H2O. Keep in mind that you only need to cool the Venusian air a couple/few dozen degrees to get the water to condense, but you need to cool the air by about 100C to get the N2.

 

#2) I really have no idea.

That's fantastic! It sounds like a really workable model for getting enough to water to meed demands! 

 

You guys are making good points. The primary reason I chose Venus is because modern science fiction hasn't done much with it, and I love the concept behind the setting. I want this to make sense though. What reason would they have for building a highly expensive colony above the atmosphere? What kind of economic trade off could there be, @DerekL1963, @Scotius

[Scotius]

Venus is rare in science-fiction literature, because it's hard to do something interesting and plausibe there, that doesn't include astronauts dying in a violent way Take a look at Ben Bova's "Venus" novel. It's a part of his "Grand Tour" series about colonisation of Solar System. But what is the focus of this particular book? Efforts to retrieve bodies of the members of the first expedition to land on the surface, never to return. Venus is that hard to survive, not many authors dare to tackle this task.

[Andrew Zachary Foreman]

3 minutes ago, Scotius said:

Venus is rare in science-fiction literature, because it's hard to do something interesting and plausibe there, that doesn't include astronauts dying in a violent way Take a look at Ben Bova's "Venus" novel. It's a part of his "Grand Tour" series about colonisation of Solar System. But what is the focus of this particular book? Efforts to retrieve bodies of the members of the first expedition to land on the surface, never to return. Venus is that hard to survive, not many authors dare to tackle this task.

The plot mostly follows the second and third generation fighting for survival as their home falls apart from wear and tear. It is a story of duct tape repair and last minute rescue. I want a good explanation for why they are there in the first place though. 

[todofwar]

1 minute ago, Andrew Zachary Foreman said:

The plot mostly follows the second and third generation fighting for survival as their home falls apart from wear and tear. It is a story of duct tape repair and last minute rescue. I want a good explanation for why they are there in the first place though. 

I would say don't get too bogged down with that part. If it were completely plausible and realistic we'd be there by now. One possibility that is plausible if not proven, is that you can take advantage of the super heated co2 close to the surface to grow nanotubes on scale in a well ordered fashion by employing the correct catalysts. No process I know of does this, so you'll need to hand wave the chemistry, but I'd say it's plausible and my background is in chemistry. Venus provides a place you can manufacture nanotubes with very little cost in that case, and space transport is just cheap enough to make it worth it back home. But maybe not worth it enough to justify rebuilding a colony once they beleive the first one went to hell.

[Andrew Zachary Foreman]

2 minutes ago, todofwar said:

I would say don't get too bogged down with that part. If it were completely plausible and realistic we'd be there by now. One possibility that is plausible if not proven, is that you can take advantage of the super heated co2 close to the surface to grow nanotubes on scale in a well ordered fashion by employing the correct catalysts. No process I know of does this, so you'll need to hand wave the chemistry, but I'd say it's plausible and my background is in chemistry. Venus provides a place you can manufacture nanotubes with very little cost in that case, and space transport is just cheap enough to make it worth it back home. But maybe not worth it enough to justify rebuilding a colony once they beleive the first one went to hell.

Haha. Went to Hell. I don't know if that was intentional but it sure was funny! Ok, then let's hand wave it, and go with your suggestion for now. If most of the facility was designed for processing the CO2 then that would mean that they would need to re-purpose the machinery for other functions, like growing food on a huge scale. Are we all in agreement now that they could survive on their own for at least five decades without outside help?  

[KerikBalm]

23 minutes ago, todofwar said:

1) Don't need to cool all that air down at once, just need to run it through a cold trap, at least for the water. A continuous flow system will net you all you need. 2) The acids will dissolve into the water, and the HF will chew through most things and is one of the few chemicals i refuse to work with because its so toxic, so that will need to be separated somehow. 

For something on this scale zeolites might be the better way to get notrogen, they can be designed to trap certain gasses. 

yes, you don't need to do it all at once, continuous flow is likely going to be more desirable than a "batch" mode. The total volume of air that needs to be processed doesn't change though

2) Well, for just the water gathering aspect, do you think these acids at 0.7 ppm are going to be concentrated enough to be a problem? I see them as a long term corrossion problem, something that will "chew through" your machine after long term use. I did derp on the idea of cooling it enough to condense the HF. Liquifying HF concentrates the HF, and in my brain fart, I forgot just how ridiculous HF is. You'd need quite a protective coating to stop HF from eating away at it.

Once the water freezes/is removed, is the situation a little better now that it can't dissolve and form an acid?

I did look it up and see this:

Quote

Unlike other hydrohalic acids, such as hydrochloric acid, hydrogen fluoride is only a weak acid in dilute aqueous solution.^[11] This is in part a result of the strength of the hydrogen-fluorine bond, but also of other factors such as the tendency of HF, H
2O, and F−
anions to form clusters.^{[note 1]} At high concentrations, HF molecules undergo homoassociation to form polyatomic ions (such as bifluoride, HF−
2) and protons, thus greatly increasing the acidity

...

In thermodynamic terms, HF solutions are highly non-ideal, with the activity of HF increasing much more rapidly than its concentration. The weak acidity in dilute solution is sometimes attributed to the high H—F bond strength, which combines with the high dissolution enthalpy of HF to outweigh the more negative enthalpy of hydration of the fluoride ion

Seems like if its kept dilute enough, it shouldn't be too bad?

Also I hadn't heard of Zeolites, those sound cool, maybe I was wrong about being unable to "filter" it out. Could we used zeolites or some other form of "chemical sponge" to remove the HF and HCl before we condense out the CO2 and SO2? What elementss would we need to make/"recharge" these chemical sponges? (if they can be obtained from the atmosphere, great)

23 minutes ago, Andrew Zachary Foreman said:

@DerekL1963That's fantastic! It sounds like a really workable model for getting enough to water to meed demands! @Scotius

Well, I may have made it sound too easy. Normally in these threads where we debate the plausibility of colonizing Venus, I argue vehemently against it... but I figured I'd try and be helpful and not just be a jerk and say colonizing Venus is a dumb idea

As noted, that HF and HCl will be more problematic than I initially assumed. Furthermore,  "only" 50,000 cubic meters to get one liter, or "only a 36.85 meter cube" pet liter of liquid water are a bit misleading. I calculated the volume of my studio apartment... nearly 60 cubic meters exactly... I'd need to condense water from air in the equivalent about 1000 of my studios, to get just 1 liter of water to drink... that is pretty bad... thats for 1 liter, imagine how much air you need to process for a whole colony of hundreds(?) of people and the crops/hydroponics to feed them! All while the air is (at least weakly) corrosive.

Can a colony getting by on 1 liter of water per 50,000 cubic meters of processed air even hope to be able to maintain machines on the scale required?

Maybe it produces enough water for 200 people, but it would take 400 to maintain the machine...

I guess you already have some good ideas for crisis that the colony will face... if nothing else you can fudge the numbers and say they barely get by when in reality it would rapidly collapse?

[todofwar]

12 minutes ago, KerikBalm said:

yes, you don't need to do it all at once, continuous flow is likely going to be more desirable than a "batch" mode. The total volume of air that needs to be processed doesn't change though

2) Well, for just the water gathering aspect, do you think these acids at 0.7 ppm are going to be concentrated enough to be a problem? I see them as a long term corrossion problem, something that will "chew through" your machine after long term use. I did derp on the idea of cooling it enough to condense the HF. Liquifying HF concentrates the HF, and in my brain fart, I forgot just how ridiculous HF is. You'd need quite a protective coating to stop HF from eating away at it.

Once the water freezes/is removed, is the situation a little better now that it can't dissolve and form an acid?

I did look it up and see this:

Seems like if its kept dilute enough, it shouldn't be too bad?

Also I hadn't heard of Zeolites, those sound cool, maybe I was wrong about being unable to "filter" it out. Could we used zeolites or some other form of "chemical sponge" to remove the HF and HCl before we condense out the CO2 and SO2? What elementss would we need to make/"recharge" these chemical sponges? (if they can be obtained from the atmosphere, great)

Well, I may have made it sound too easy. Normally in these threads where we debate the plausibility of colonizing Venus, I argue vehemently against it... but I figured I'd try and be helpful and not just be a jerk and say colonizing Venus is a dumb idea

As noted, that HF and HCl will be more problematic than I initially assumed. Furthermore,  "only" 50,000 cubic meters to get one liter, or "only a 36.85 meter cube" pet liter of liquid water are a bit misleading. I calculated the volume of my studio apartment... nearly 60 cubic meters exactly... I'd need to condense water from air in the equivalent about 1000 of my studios, to get just 1 liter of water to drink... that is pretty bad... thats for 1 liter, imagine how much air you need to process for a whole colony of hundreds(?) of people and the crops/hydroponics to feed them! All while the air is (at least weakly) corrosive.

Can a colony getting by on 1 liter of water per 50,000 cubic meters of processed air even hope to be able to maintain machines on the scale required?

Maybe it produces enough water for 200 people, but it would take 400 to maintain the machine...

I guess you already have some good ideas for crisis that the colony will face... if nothing else you can fudge the numbers and say they barely get by when in reality it would rapidly collapse?

You have to remember that 0.7 ppm dissolved in 20 ppm means your close to a 5% solution, and drinking 5% HF will kill you. Hell, getting that concentrated an HF solution on your skin is enough to kill you.

You recharge zeolites by heating them under vacuum, no need for other chemicals.

[KerikBalm]

Except its not 0.7ppm disolved in 20 ppm. That 20 ppm goes to zero as water leaves the air. Then its a small volume of nearly pure liquid water exposed to 0.7ppm HF/HCl.

... A small volume of water, of course, so maybe it reaches equlibirum quickly due to surface area to volume ratios, but its certainly going to be different than a 5% mixture of the two, no?

[todofwar]

11 minutes ago, KerikBalm said:

Except its not 0.7ppm disolved in 20 ppm. That 20 ppm goes to zero as water leaves the air. Then its a small volume of nearly pure liquid water exposed to 0.7ppm HF/HCl.

... A small volume of water, of course, so maybe it reaches equlibirum quickly due to surface area to volume ratios, but its certainly going to be different than a 5% mixture of the two, no?

Now that is a good question. The water will most certainly begin dissolving the acids as soon as it liquefies, and may even pull in acids with it as an azeotrope. If you can get the water away from the gasses quickly enough, maybe you can stop it from dissolving too much of the acid.

[KerikBalm]

Well, lets assume you leave the water there for a while, when the vapor pressure of the HF/HCl in the water matches that of the partial pressure of HF/HCl atmosphere, it should stop absorbing more, no?

If the partial pressure in the atmosphere is 0.7 ppm, then there shouldn't be that much HF/HCl in the water before the HF/HCL leaves the water at the same rate at which it enters. I'm an expert in cell biology, not chemistry... (I have a basic knowledge of chemistry, but not very detailed) but I'm pretty sure this would prevent the HF/HCl concentration from getting anywhere near 1%.

[todofwar]

I would think it could dissolve all of it. A 10% solution of HCl doesn't spontaneously out gas all the HCl when you open the bottle. 

[KerikBalm]

but there are fumes.... give it long enough... we're not talking about the time to outgass to equilibrium, but the time to absorb to equilibrium.

Some actual math could really help here if you know the equations off the top of your head, it would be great

[todofwar]

34 minutes ago, KerikBalm said:

but there are fumes.... give it long enough... we're not talking about the time to outgass to equilibrium, but the time to absorb to equilibrium.

Some actual math could really help here if you know the equations off the top of your head, it would be great

I haven't had to deal with those kinds of dynamics in a while, but I think you may have a point. I'm sure someone has done all kinds of work on this in the 50s. 

[CSE]

To get a rationale for a colony that is mostly scientist and has to be located on Venus: something of scientific interest is found on Venus that Needs Further Study^TM and, perhaps, can't be removed from Venus as a one-off and then studied at length somewhere more hospitable.

For example: small particles are found at low concentrations in Venus' atmosphere that have some similarities to living organisms. Handwavium venerae decays/dies/transforms into less interesting pieces in a timescale of days/weeks/months. Perhaps it's a Venus-native lifeform, or descended from Earth life accidentally carried by earlier probes. Perhaps it's a precursor to genuine organisms, or a kind of pseudo-life like a prion or virus. Perhaps it's something else entirely. It's of academic interest for the origins of life, and of commercial interest for potential biotech or nanotech, and of governmental interest for potential disease or environmental contamination or weaponization. Attempts to grow, replicate, or artificially manufacture H. venerae have so far met with failure. And so a long-term mission is sent to Venus to (i) gradually gather more from the atmosphere and study it, (ii) attempt to copy or create it in a lab with a Venus-like environment, (iii) search Venus for its origins.

...

I really like the image of an airship colony where the hab and greenhouse is the inside of the balloon, with machinery and labs in the gondola underneath. I can't help but agree with everyone above that it'll be really difficult to pull off in a hard-ish SF setting. Best of luck!

[kunok]

You want one reason? In the future (the past in your history) is demonstrated that no gravity, reduced gravity (like the one in mars), or Coriolis effects (like the ones you have in a centrifugal station) are very harmful to the health in mid term, and incompatible with gestation.

Then Venus is the only option outside Earth. You can make one prologue talking how other colonies failed before attempting Venus.

 

Thought I really think that Venus is easier than Mars (carbon and plastic based building and manufacturing), and has the exactly same reason to go there, zero, only to discover to go to new places, to adventure.

[Bill Phil]

If it were up to me, I'd forego planets entirely, but it's not up to me. Venus would probably be the best bet due it being close to Earth's gravity.

[KerikBalm]

On 10/2/2016 at 11:35 PM, kunok said:

You want one reason? In the future (the past in your history) is demonstrated that no gravity, reduced gravity (like the one in mars), or Coriolis effects (like the ones you have in a centrifugal station) are very harmful to the health in mid term, and incompatible with gestation.

Then Venus is the only option outside Earth. You can make one prologue talking how other colonies failed before attempting Venus.

 

Thought I really think that Venus is easier than Mars (carbon and plastic based building and manufacturing), and has the exactly same reason to go there, zero, only to discover to go to new places, to adventure.

Plastics require hydrogen, as noted, there is a severe hydrogen shortage, the only things you can do with just carbon is diamond, graphite, and bickyballs. You would still need various metals for electronics, as well as life (plants need magnesium for chlorophyl, animals need iron for hemoglobin, we also need copper, sodium, potassium, manganese, etc)... and again... hydrogen. I really don't understand how you can think that a cloud colony on venus is a better option than a surface or subsurface colony on mars...

As to your coriolis effect... just build a larger diameter centrifuge and the effects decrease. That would be easier than colonizing venus. Also... why does this matter, its just talking about long term habitation for the purpose of... long term habitation. It won't reduce overcrowding on Earth, it won't be economically profitable.

The only possible reasons are scientific or political

 

On 10/2/2016 at 7:50 PM, CSE said:

To get a rationale for a colony that is mostly scientist and has to be located on Venus: something of scientific interest is found on Venus that Needs Further Study^TM and, perhaps, can't be removed from Venus as a one-off and then studied at length somewhere more hospitable.

For example: small particles are found at low concentrations in Venus' atmosphere that have some similarities to living organisms. Handwavium venerae decays/dies/transforms into less interesting pieces in a timescale of days/weeks/months. Perhaps it's a Venus-native lifeform, or descended from Earth life accidentally carried by earlier probes. Perhaps it's a precursor to genuine organisms, or a kind of pseudo-life like a prion or virus. Perhaps it's something else entirely.

The extreme scarcity of water and hydrogen containing compounds pretty much rules out any life. Cloud life isn't going ot be a thing despite benign temperatures and pressures at 50km.

Maybe some sort of artifacts from an ancient civilization on Venus 1+ billion years ago before the runaway greenhouse boiled off all the oceans and turned it into the heck hole it is today...

Perhaps the reduction in pressure and temperature combined with the strong winds they'll encounter when they are lifted out of the atmosphere cracks/shatters/destroys them. They need to be studied on the surface, so you need a colony right there to service the surface robots that examine them... plus having the colony right there reduces signal delay and allows the surface craft to drive around in real time.

Although even in this scenario, I think some sort of high pressure "oven" container that the objects could be loaded into before lifting them up would be easier.

[kunok]

9 minutes ago, KerikBalm said:

Plastics require hydrogen, as noted, there is a severe hydrogen shortage, the only things you can do with just carbon is diamond, graphite, and bickyballs. You would still need various metals for electronics, as well as life (plants need magnesium for chlorophyl, animals need iron for hemoglobin, we also need copper, sodium, potassium, manganese, etc)... and again... hydrogen. I really don't understand how you can think that a cloud colony on venus is a better option than a surface or subsurface colony on mars...

It's far easier to trap hydrogen compounds in the atmosphere than mining in vacuum, it will take time but is not like a colony grows every day.

The metals needs for organisms are very little, you can deal with that with a supply, or even trying to get some rocks from the surface (I have an idea how to do that "easily", I will post sometime when I have time to make the sketch).

Carbon and plastics based conductors and electronics are a future thing, sure. But if the life support is based in plants, a established colony maybe can deal without them, blimps, plastics, and soilless plant growing precedes electronics. I would have designed that way.

How do you deal with that in mars or whatever is it? You need different chemical process to deal with diferent ores for different metals and every one of them will need a huge installation, people underestimate the size and complexity of the metal industry even trying to make it in minimum size, and that's not accounting with all the auxiliary industry it needs. And probably if you need different ore for the needs of one type of industry every one of them will be far from the others

[KerikBalm]

4 hours ago, kunok said:

It's far easier to trap hydrogen compounds in the atmosphere than mining in vacuum, it will take time but is not like a colony grows every day.

And even easier to just scoop up water ice, like one can find on Mars.

Quote

The metals needs for organisms are very little, you can deal with that with a supply, or even trying to get some rocks from the surface (I have an idea how to do that "easily", I will post sometime when I have time to make the sketch).

Carbon and plastics based conductors and electronics are a future thing, sure. But if the life support is based in plants, a established colony maybe can deal without them, blimps, plastics, and soilless plant growing precedes electronics. I would have designed that way.

How do you deal with that in mars or whatever is it? You need different chemical process to deal with diferent ores for different metals and every one of them will need a huge installation, people underestimate the size and complexity of the metal industry even trying to make it in minimum size, and that's not accounting with all the auxiliary industry it needs. And probably if you need different ore for the needs of one type of industry every one of them will be far from the others

I think you underestimate the complexity of manufacturing your plastics based economy on Venus... And even so, its easy enough to get carbon on Mars to, so thats still not an advantage to Venus.

Picking up some rocks from the surface of Venus? what happens when you need to drill to find the right mineral vein? your mining equipment needs to withstand ~400C temperature adn 90 atms, in a corrosive atmosphere. In mars you can move all that equipment around easily in low gravity, and smelt it on site. You can use Iron, Carbon, or whatever material is most convenient.

Sure Carbon is denser in Venus's atmosphere, but plastics are hydrocarbons, and to get the 2 hydrogens for each carbon in a hydrocarbon chain, you'll need to process roughly 50,000 liters of atmosphere just to have enough hydrogen to combine with the carbon in one liter of its atmosphere.

Mars: You just compress the atmosphere 100x and scoop up some ice... done...

But I think this could lead to hijacking the thread, and there are already threads for the venus vs mars question.

Lets stop making comparisons to other potential places to colonize, and just limit it to the OPs question on colonizing Venus for ... reasons...

[CSE]

8 hours ago, KerikBalm said:

Maybe some sort of artifacts from an ancient civilization on Venus [...] Perhaps the reduction in pressure and temperature combined with the strong winds they'll encounter when they are lifted out of the atmosphere cracks/shatters/destroys them.

Would also be a good rationale for a scientific colony. The artefacts or something related to them needs to be accessible in Venus' cloud layer, though, or why place the colony there rather than in orbit.

I also think there needs to be some uncertainty about why the thing goes wrong when you take it somewhere other than Venus. From a hard-SF viewpoint, if it was a well-understood environmental requirement like pressure then it could be replicated somewhere more hospitable than Venus. And from a story-telling point of view, if some parts of a setting are meant to be (and stay) unknown to the characters then it can make the story world 'real' to the author if some parts of the setting are unknown to the author too. A kind of author-immersion, if you will. See Tolkien's Tom Bombadil for an example.

[KerikBalm]

3 hours ago, CSE said:

Would also be a good rationale for a scientific colony. The artefacts or something related to them needs to be accessible in Venus' cloud layer, though, or why place the colony there rather than in orbit.

Because getting them to orbit is a lot harder than getting them to a cloudbase. Getting to orbit from venus' surface will be much much much harder than getting to orbit from Earth's surface. The orbital velocity is almost the same, but the aerodynamic drag will be much greater, insulating any cryogenic fuel will be much harder. The structure would be much heavier to tolerate the heat and pressure, and the engines would have way less Isp.

In contrast if you've got a floating base, you just winch it up

Quote

I also think there needs to be some uncertainty about why the thing goes wrong when you take it somewhere other than Venus. From a hard-SF viewpoint, if it was a well-understood environmental requirement like pressure then it could be replicated somewhere more hospitable than Venus. And from a story-telling point of view, if some parts of a setting are meant to be (and stay) unknown to the characters then it can make the story world 'real' to the author if some parts of the setting are unknown to the author too. A kind of author-immersion, if you will. See Tolkien's Tom Bombadil for an example.

Well, if we went with the alien artifacts on the surface of venus, maybe they self destruct if they detect that they've been removed from venus... I don't know.

Introducing aliensalien artifacts into a story shouldn't be done lightly... but I really can't think of another reason to make such a base