Floating Venusian cities or Venus vs Mars vs Titan revisited

noosfractal · 2007-04-15 22:33:29

Why wait to start a design process we do have a poor representation in orbit to make sure that we do it right on the first try. Yes I speak of the ISS which needs constant resupply, reboosting of orbit and while it has an open loop LSS it has no means to pull in the atmosphere to allow for things to change.

It's like baby pictures of our first L5 colony. Awww, cute little ISS

noosfractal · 2007-04-15 23:00:08

I am not sure what you are mean when you say "the Mars launch is still behind for the NVA". Are you suggesting we should go after NVA from Mars?

No, I was saying that there are a set of asteroids (the NVAs) that you wouldn't go after from Mars, and then went on to speculate on the scenarios under which that set of asteroids might be more economically valuable (for at least some period of time) than the corresponding set of asteroids that you wouldn't go after from Venus (the NMAs). If such a scenario arose and you were a asteroid mining entrepreneur, you might build an asteroid mining support base at Venus (or L5) instead of Mars.

If Venus is forced to compete with Mars by launching big dumb boosters from the cloud tops then it is going to have a hard time overcoming the delta-v penalty. However, if asteroid miner manufacture takes place in low Venusian orbit directed telerobotically from the luxurious diamond cities below, then the penalty drops dramatically, especially if delta-v achieved with solar or magnetic sails is considered free delta-v.

John Creighton · 2007-04-17 09:09:48

If Venus is forced to compete with Mars by launching big dumb boosters from the cloud tops then it is going to have a hard time overcoming the delta-v penalty.

With Venus's thicker atmosphere and slightly lower gravity then earth, scram jets and ram jets will work at higher altitudes then on earth. I am not sure if that give Venus any edge over mars though since Mars requires less Delta V to launch from then Venus.

nickname · 2007-04-17 09:56:05

Depends if we take into account all the abundant free fuel and solar power at Venus.

Delta V worse at Venus, but production of fuels to overcome the difference might be a big plus at Venus and a big minus on Mars.

noosfractal · 2007-04-17 12:04:58

With Venus's thicker atmosphere and slightly lower gravity then earth, scram jets and ram jets will work at higher altitudes then on earth.

Unfortunately Venus' atmosphere is oxygen-poor, so being airbreathing wouldn't give you much of an advantage. Maybe some other type of low cost to low orbit infrastructure though - perhaps airship to orbit or aerovator.

John Creighton · 2007-04-17 22:40:33

With Venus's thicker atmosphere and slightly lower gravity then earth, scram jets and ram jets will work at higher altitudes then on earth.
Unfortunately Venus' atmosphere is oxygen-poor, so being airbreathing wouldn't give you much of an advantage. Maybe some other type of low cost to low orbit infrastructure though - perhaps airship to orbit or aerovator.

Good point. I wonder how well airship to orbit would work on Venus. I've never heard of aerovator before though.

nickname · 2007-04-18 04:01:28

John Creighton,

How about cover it in solar panels and separate C02 into 02.?

02 is lighter than C02 so you can float in the cloud tops, when you have stayed as long as you like, then go as high as the buoyancy will take you with some heat added to the 02 in your blimp.
At that point compress the 02 inside the air ship into liquid 02 and use it as rocket fuel.

It makes for a pretty simple vehicle and totally reusable, might even be able to carry extra 02 or C or sulphur or h20 to orbit.
Venus might not be such a bad place to fuel up.

If we use the waste C from the C02 seperation process we might even be able to make more Venus air ships from it, or at least most of a new ship.

noosfractal · 2007-04-19 13:44:21

I've never heard of aerovator before though.

1000 km ribbon spun from a central hub. The ribbon has an aerodynamic shape that provides lift. The ribbon ramps steeply from the hub. Most of the ribbon skims the "top" of the atmosphere keeping the whole structure aloft. You launch things from the hub. May need a rocket boost up the first section, but eventually the payload is flung from the end of the rotating ribbon into orbit.

Why is it interesting? Preliminary analysis says it can be built with known materials. No CNTs required. CMEdwards says here ...

http://www.newmars.com/forums/viewtopic … 6&start=21

... that it can't be deployed, but compared to the space elevator it is a stroll in the park.

Unfortunately the wikipedia article was deleted as original research, but you can find the text on one of the clones ...

http://en.allexperts.com/e/a/ae/aerovator.htm

Ongoing discussion here ...

http://tech.groups.yahoo.com/group/spac … =aerovator

StarDreamer · 2007-04-29 11:28:04

Let's focus this one a little more narrowly. We've presented with the almost poetic image of cities floating in the Venusian atmosphere, I guess slowly drifting downward as centuries or millenia of terraformation convert a Carbon Dioxide atmosphere into a Nitrogen-Oxygen one, the cities coming down to a new earth out of a new heaven (and don't ask me where the Nitrogen is coming from, because I have no idea). A few Christian fundamentalists might be absolutely intrigued by the parallel with the image of the new Jerusalem in Revelations, but as much fun as we could probably all have with the subject of the cultural implications of all of this, one can possibly shoot the idea down in one word.
Convection.
The heat engine on Venus is going to be a lot more powerful than the one on earth, and I have to wonder what is going to happen to one of those floating cities when it floats into a downdraft. Yes, it has bouyancy pushing it back up, but one can say the same of any unfortunate swimmer who gets himself caught in an undertow. He still goes down. Any reputable studies done of how much force our meterological undertow (convection powered downdrafts) would place on those bobbing cities, and how far down one of those cities might drop?

I have just reinvigorated the original thread, but I want to address this issue of convection as well.

From what I have read, Venus has two distinct layers of atmosphere of at least one bar or higher. Planetary atmospheres are best understood as systems of zonal equilibria.

For ex, Earth has one tropical zone, two flanking temperate zones and two polar zones. Prevailing winds in adjacent zones move in opposite directions. During the last glaciation, prevailing winds in modern temperate latitudes were polar easterlies -- ie: the polar zone pushed south and the tropical zone was compressed or perhaps even non-existent. The doldrums and "horse latitudes" of still air mark the zonal boundaries where air currents are moving away in both directions and there is no inflow to push on a sailboat.

Zonal equilibria are a function of insolation, axial tilt and atmospheric viscosity. Earth has space to accomodate only five zones. Global warming will convert the two polar zones to temperate climates and give rise to a supertropical zone at the equator. When the tipping point is reached, the whole zone will reverse its mechanics and settle into a new equilibrium.

Jupiter and Saturn have many more than 5 zones; hence the bands of alternating clouds. Mars has at least 3 zones.

Because of the incredible viscosity of Venus atmosphere, I don't think we know how many zones it has yet. BUT, I think its atmosphere is so deep that it has two layers of zonal climates. The high velocity winds at mid altitudes mark this boundary. There is a boundary there -- clouds of sulphuric acid and water vapour exist only in the upper system. This gives rise to the need to consider an atmosphere that is fully circulating in more than one axis, where convection currents may be as powerful as cyclonal currents. Think of an oldfashioned wringer washer machine. A convection downdraft from the upper zone will be met by a matching updraft from the planet surface. Then both winds shall turn and merge along the mid-depth boundary as a supersonic wind until it comes to the next matching pair of drafts where, this time, one wind shall turn up and rise and the other shall sink down again. I feel certain this is how sulphur gets transferred up from the surface.

A bubble colony caught in a downdraft would be pulled down and sucked into this mid-depth conveyor belt and driven along at terrific speed to the next zonal boundary, where it would then either rise back to the cloudtops or be sucked down to the surface. The path to the surface from the cloudtops is not a vertical drop but a high speed S-curve, down, across and then down again. If it survives the conveyor belt portion of the trip, its buoyancy should guarantee a return to the cloudtops.

Conclusion: cloudtop colonies will need to be vigilant about maintaining neutral positions in the atmosphere and they will need ready and dependable power sources NOT dependent on aerodynamics to overcome rough weather.

Bryan

StarDreamer · 2007-04-30 10:13:39

Depends if we take into account all the abundant free fuel and solar power at Venus.
Delta V worse at Venus, but production of fuels to overcome the difference might be a big plus at Venus and a big minus on Mars.

Yes, exactly -- it is a trade-off. I say healthy gravity and free atmosphere on Venus outweigh low gravity and sparse resources on Mars. The energy expenditure to get in and out of Venus becomes less daunting if that energy can be cheaply won. Mars may have lower delta-V, but what good is that if that energy must be imported from off the planet or if concentrating that energy means robbing the planet of the very resources it most desperately needs to sustain future life?
Bryan

nickname · 2007-04-30 16:58:10

StarDreamer,

Welcome to New Mars.

I agree Venus and Mars both have trade offs.
Like you say Mars is never going to be a good resource for fuel so the Venus abundance might prove to be a big bonus.

Even with the technology we have now using solar power and separation of co2 Venus looks like a much better place to fuel all space ventures.

Mars is sure to be the next real home of humans, Venus probably never a home.

We should probably think of Venus as just a store of Carbon and Oxygen in pretty much unlimited amounts, with plenty of free power to extract both.

Using the clouds on Venus as a home at best is a risky venture.
In the zone that human life could exist, it also rains concentrated sulfuric acid, a point most cloud city people probably haven't thought about much.

Sure we could overcome the sulfuric acid rain but it means staying inside a fortress 24/7.
Makes little sense to go if we are living in a can, we can do that anywhere.

Probably the best use for Venus i can think of is to terra form Mars.
1 bar of that 99% CO2 atmosphere would do the trick, maybe as little as 250mb sent to Mars from Venus would take the chill and low pressure off.

Venus has so much atmosphere we could probably terra form everything in the entire solar system, use free co2 separated fuel at Venus, build most of the transports from Carbon, and still have 40 or 50 bars left over LOL

StarDreamer · 2007-04-30 18:04:51

StarDreamer, Welcome to New Mars.

Thank you! I see you are in Ontario too. Obviously not Laucus Ontario ... (That, apparently, is on Titan.)

Mars is sure to be the next real home of humans, Venus probably never a home. Using the clouds on Venus as a home at best is a risky venture.
In the zone that human life could exist, it also rains concentrated sulfuric acid, a point most cloud city people probably haven't thought about much.

Actually, I made particular mention of the sulphur problem in my first post on this board. I think sulphur is a bigger problem on Venus than the CO2 or the heat or the pressure. The metals we would want to use as catalysts for scrubbing the CO2 would be eaten voraciously by the sulphuric acid long before they could process their worth of CO2. We must scrub the sulphur first and sequester that. If there is a steady supply of sulphur coming up from the surface, then we will never get ahead of it all. Then the only answer is to sunshade the planet, freeze out the atmosphere and release the heat which is obviously powering the sulphur skywards.

What is inert in the face of sulphur? Are there any catalytic reactions capable of pulling it out? Or must we leave it up to the bacteria?

If we can hold the sulphur at bay, then everything else can work. I do not foresee cloud cities per se. I see outposts and farms, a la Tatuine (Star Wars). I see very function-specific cloud platforms of various kinds and solar-powered glider craft swooping between them. One bubble might be a landing port for inbound vehicles from space. Another might be a fullerene factory. Another might be a market outpost for farmers to trade their stuffs. A great many would be communal farms growing veggies and fruits hydroponically on a base of bacteria and algae. Others would be unmanned element scrubbers of various kinds.

The survival of the enterprise as a whole is infinitely more important than the survival of any single bubble. The only way to manage risk is by spreading it thinly and cheaply. This can be done on Venus far more cheaply than on Mars. On Mars, the strategy would most likely be to huddle together in one urban centre, for safety and for maximal use of energy expended in creating and maintaining that space. But one impactor on Mars in the wrong place (and I saw the thread on here detailing the dozen that hit in a small area over the past 20yrs!) would destroy our whole planet's effort. On Venus we can deploy thousands of bubbles and let them wander where they may. Each one is equipped for self-sustained long-term success and survival. If some fail and sink into the crushing furnace, that will be sad, even tragic, but not unexpected and not the harbinger of systemic failure. Mars settlement, with the need for domes and burrows and power stations and heavy machinery, will demand high investments in each venture and a lot of central control.

Probably the best use for Venus I can think of is to terra form Mars.
1 bar of that 99% CO2 atmosphere would do the trick, maybe as little as 250mb sent to Mars from Venus would take the chill and low pressure off.
Venus has so much atmosphere we could probably terra form everything in the entire solar system, use free co2 separated fuel at Venus, build most of the transports from Carbon, and still have 40 or 50 bars left over LOL

I agree. But terraforming Mars will take centuries, while Venus can be colonised without massive terraforming. That is the distinction!

Bryan

nickname · 2007-05-01 06:28:29

StarDreamer,

Well sulphur is good and bad at Venus.
Sulphur is the main reason for clouds also the reason for sulfuric acid rain.

If you could remove all the sulphur from Venus the habitable zone would disappear, the temperature would rise considerably as the clouds also dissapear.
This might impart a considerable expansion of the atmosphere allowing faster solar degradation of the co2 atmosphere to space, but at 92 bars a degradation at even accelerated pace will take nearly forever.

The water contained in the sulfuric acid would be separated fast from intense UV separation to Oxygen and Hydrogen, then Hydrogen quickly lost to space, so a big resource at Venus would also be lost when removing the sulphur.

I question if it is easier to settle Mars or Venus.
Mars can be settled underground quite easily, once we remove the two main problems at Mars... the cold and thin atmosphere it is ready.
Going underground allows easy solutions to both and offers a third radiation protection.

At Venus to make a settlement we need huge rockets and huge equipment to make a cloud city before we could settle.
It has to be adjustable in any wind so it will need lots of fuel, lots of backup solutions, lots of acid protection, emergency escape vessels etc etc.
All big resources a long way from another big gravity well Earth.

If we use Venus as a fuel depot or fuel and food depot then all sorts of possibilities open up.
No need for escape vehicles for carrots

In my opinion we don't need to attempt to terra form either Mars of Venus.
Just use what they offer and make the best use of what they have.

London Ontario here

Spatula · 2007-05-03 23:43:25

(and don't ask me where the Nitrogen is coming from, because I have no idea)

3.5% of Venus's atmosphere is Nitrogen. Removing all the CO2 would result in a Nitrogen atmosphere 3.21 times as thick as Earth's.

So the question should not be 'where do we get the Nitrogen from', but 'how are we going to get rid of all this extra Nitrogen'?

Josh Cryer · 2007-05-06 12:32:14

3.5% of Venus's atmosphere is Nitrogen. Removing all the CO2 would result in a Nitrogen atmosphere 3.21 times as thick as Earth's.
So the question should not be 'where do we get the Nitrogen from', but 'how are we going to get rid of all this extra Nitrogen'?

Really? I always wondered where the Nitrogen to thicken Mars' atmosphere would come from. There's your answer.

Spatula · 2007-05-07 00:13:31

3.5% of Venus's atmosphere is Nitrogen. Removing all the CO2 would result in a Nitrogen atmosphere 3.21 times as thick as Earth's.
So the question should not be 'where do we get the Nitrogen from', but 'how are we going to get rid of all this extra Nitrogen'?
Really? I always wondered where the Nitrogen to thicken Mars' atmosphere would come from. There's your answer.

Glad we're on the same page then.

Of course I'm sure some of you are wondering how we'll move 2 earths worth of Nitrogen between planets. By then we will have moved 10^19th kg worth of hydrogen to Venus to sequester its atmospheric carbon dioxide as water and organic compounds. How the hell will we do that? Hundreds of years and hundreds of quadrillions of real dollars, is the only answer I can think of.

Worth every cent, I'd say. It would make extracting natural resources much cheaper on these planets in the long run. It's also a good insurance policy. It would pay off.

nickname · 2007-05-08 04:56:27

Spatula,

Before we think about moving anything from Venus to try and terra form it, we should probably think about where the additional heat on Venus is coming from.

If we take into account all the solar, C02 atmosphere and possible heat generated atmospheric conditions, Venus is still much hotter than the temperature can account for.

My guess is that Venus produces a lot of heat from the core directly to the surface.

Something like scraping away 20km of earths crust would on earth.

If that is true then nothing we do will ever terra form Venus.

Moving 1 bar of nitrogen from Venus to mars is possible but long term.
With a very sustained effort 1 bar of nitrogen will require about the same energy that all of earth has produced in the last 50 years and take around 36,000 years to complete.

In my opinion Mars could use just the native Venus atmosphere more than a nitrogen import.

We could move 1 bar of native Venus atmosphere with almost no output energy.
If we take advantage of the mainly co2 atmosphere to move the c02 atmosphere as separated C for storage and transport vehicles and 02 as the fuel to move, then we can probably move 1 bar of it to mars in as little as 1000 years.

Moving 1 bar of Venus atmosphere will make mars a 3% nitrogen atmosphere anyway.

My guess is that as little as 1/4 bar of Venus atmosphere sent to mars would set the melt going at mars.

StarDreamer · 2007-05-08 06:33:16

Am I right in thinking that one bar of atm on Mars is less gas than one bar on Venus or on Earth? Because it is a smaller planet ... Therefore it just takes less gas to achieve one bar of pressure at the surface. And do we know how much less gas this means? And are we taking this into consideration in calculations of time estimates, etc.?

Bryan

nickname · 2007-05-10 19:35:53

StarDreamer,

Thinner atmosphere on Mars due to less gravity.

1 bar of venus atmosphere sent to mars would be one bar of pressure in a 1/3 gravity well.

Math not that simple as 1/3 bar though.
I believe you get about 1/2 to 3/5 of 1 bar on mars spread to higher altitudes.

I could be totaly wrong though, not a study i am very familiar with.

Interesting point though.

StarDreamer · 2007-05-10 23:32:11

StarDreamer,
Thinner atmosphere on Mars due to less gravity.
1 bar of venus atmosphere sent to mars would be one bar of pressure in a 1/3 gravity well.
Math not that simple as 1/3 bar though.
I believe you get about 1/2 to 3/5 of 1 bar on mars spread to higher altitudes.
Interesting point though.

Less gravity on Mars explains why atmosphere has been lost to space, yes. But what I am driving at is the land surface area of the planet. One bar is, I believe, a measure of pressure, therefore weight per square measure of area.

If gravity be disregarded for the moment, less mass is required to achieve one bar of pressure on Mars than on Venus or Earth just because the planet is smaller and has less surface area, so that the gas molecules cannot spread out as much on the ground. If you took Venus down from 92 bars to 91 bars and transferred that bar to Earth, then because Earth is a slightly larger planet than Venus, that additional volume of gas should not take us from 1 bar to 2 bars, but perhaps only to 1.8 bars. But that same mass of gas delivered to Mars might get you 2.3 bars extra, just because the planet is more crowded at Ground Zero.

StarDreamer · 2007-05-11 18:27:39

nickname --

I see today that you were trying to say the same thing I was, but I didn't get the explanation -- yes, 1 bar on Mars is not 0.333 bar just because it is 0.333 gravity, but actually maybe 0.5-0.6 bar because the mass of the gas is more confined at the bottom of the column.

Maybe 0.5 bar in the southern hemisphere and 0.6 bar in the northern. Maybe 0.7 bar in the canyon depths.

By the way -- hello to London. My mother was born there. I am in Kitchener.

Bryan

StarDreamer · 2007-05-11 18:34:01

Can anyone think of any chemical reaction which would be capable of displacing the sulphur from the sulphuric acid or sulphur dioxide on Venus, but still keep bound the precious hydrogen and oxygen? The goal is simply to get a less noxious, less heat-retensive atmosphere (and H2SO4 holds a lot of heat!). Or what is inert in the face of H2SO4?

Bryan

noosfractal · 2007-05-12 00:08:33

Can anyone think of any chemical reaction which would be capable of displacing the sulphur from the sulphuric acid or sulphur dioxide on Venus, but still keep bound the precious hydrogen and oxygen? The goal is simply to get a less noxious, less heat-retensive atmosphere (and H2SO4 holds a lot of heat!).

You could seed the sulfuric acid clouds with potassium hydroxide to create potassium sulfate and water.

Or what is inert in the face of H2SO4?

Dilute sulfuric acid is usually stored in glass or special plastic containers. However, the sulfuric acid in Venus' atmosphere is probably very pure - without water present it won't react with most metals (commercial quantities are stored at high purity in stainless steel containers).

nickname · 2007-05-12 05:08:53

StarDreamer,

Wish i could be more sure on a answer about the 1 bar Venus atmosphere to Mars question.

More of a guess than anything on my part that the gravity on Mars would just allow the gas to spread further than on Venus.

Hopefully someone will dive in and give a productive answer.

Kitchener is just a stones throw away.
Howdy Kitchener.

noosfractal · 2007-05-14 00:42:01

StarDreamer,
Thinner atmosphere on Mars due to less gravity.
1 bar of venus atmosphere sent to mars would be one bar of pressure in a 1/3 gravity well.
Math not that simple as 1/3 bar though.
I believe you get about 1/2 to 3/5 of 1 bar on mars spread to higher altitudes.
Interesting point though.
Less gravity on Mars explains why atmosphere has been lost to space, yes. But what I am driving at is the land surface area of the planet. One bar is, I believe, a measure of pressure, therefore weight per square measure of area.

You're basically right StarDreamer. It's actually very complicated because pressure depends on temperature and as soon as you added a significant amount of CO2 to Mars you would raise the global average temperature and probably melt the poles, etc, etc. But to a first approximation, it's just

delta P_mars = delta P_venus * g_mars / g_venus * surface_area_venus / surface_area_mars

So 1 bar of Venus' atmosphere -> 1.32 bar on Mars

It is a waste of energy to lift gas out of Venus' gravity well, however. A more efficient source of millibars (as well as much needed nitrogen) is ammonia asteroids, some of which have a delta-v to Mars as low as 0.5 km/s, see ...

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

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#26 2007-04-15 22:33:29

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#27 2007-04-15 23:00:08

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#28 2007-04-17 09:09:48

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#29 2007-04-17 09:56:05

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#30 2007-04-17 12:04:58

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#31 2007-04-17 22:40:33

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#32 2007-04-18 04:01:28

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#33 2007-04-19 13:44:21

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#34 2007-04-29 11:28:04

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#35 2007-04-30 10:13:39

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#36 2007-04-30 16:58:10

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#37 2007-04-30 18:04:51

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#38 2007-05-01 06:28:29

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#39 2007-05-03 23:43:25

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#40 2007-05-06 12:32:14

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#41 2007-05-07 00:13:31

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#42 2007-05-08 04:56:27

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#43 2007-05-08 06:33:16

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#44 2007-05-10 19:35:53

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#45 2007-05-10 23:32:11

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#46 2007-05-11 18:27:39

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#47 2007-05-11 18:34:01

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#48 2007-05-12 00:08:33

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#49 2007-05-12 05:08:53

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

#50 2007-05-14 00:42:01

Re: Floating Venusian cities or Venus vs Mars vs Titan revisited

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