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#1 2007-04-30 22:09:11

X
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From: Alabama
Registered: 2007-02-02
Posts: 134

Re: Given the recent rennaissance in Venutian Cloud Cities here

What would be the best way to get around Venus?

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#2 2007-05-01 17:30:09

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

fly.

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#3 2007-05-01 21:23:49

X
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From: Alabama
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Re: Given the recent rennaissance in Venutian Cloud Cities here

In what?  Helicopters?  Blimps?  Zeppelins?  Bicycle propelled balloon capsules?  Airplanes?

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#4 2007-05-04 06:08:34

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

I don't think there is any good reason to make floating city on Venus compared to making “floating” city in orbit around Venus. 0.9 g is nice, but you can make the same thing by spinning station. Atmosphere is a death trap. One problem and you crash to 90 bar pressure and 460 degrees C surface. Access from/to space is difficult (it’s like trying to launch from Earth to LEO). And, did I mention that atmosphere?

So, the only way to move “on” Venus is to fly. If you manage to cool everything then you could use balloons, planes, helicopters, or anything else, but I don’t thing we will see them anytime soon if ever.

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#5 2007-06-10 14:18:24

samy
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Atmosphere is a death trap.

Only at certain altitudes, which we can avoid.

One problem and you crash to 90 bar pressure and 460 degrees C surface.

Oh I see, you're going for the "designers are idiots because that's the only way I can come up with a far-fetched disaster scenario so I can doomsay".

Any *intelligent* designer will include redundancies, so any *one* problem won't end up crashing the float.

You could also say that "one problem and a terrestrial hot air balloon falls to the ground from 1km altitude". You know what? People still go up in terrestrial hot air balloons. When's the last time you've heard of a balloon accident on Earth? Here's a hint: they're very rare. You know why? Because this is proven, well understood technology that our civilization has mastered to a *very* high level.

The only real problem with terrestrial zeppelins was hydrogen use (Hindenburg), but since hydrogen would not be used on Venus, even that problem is eliminated.

This is very well understood, mastered, functional technology. Humans can do balloons *very* well.

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#6 2007-06-10 15:00:24

samy
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From: Turku, Finland
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Density (air) =~ 1.2kg/m3
Density (CO2) =~ 1.9kg/m3

1 cubic meter of air =~ 0.7kg of lift.

r = 6.2 m
V = 4/3pi*r3 =~ 1000 m3

A 6.2 meter radius balloon of breathable air will be able to sustain 700kg of equipment in midair indefinitely.

If there are people included in that 700kg, then the oxygen in the breathable air will convert to CO2, thus losing lift. As more and more people breathe for longer and longer, the balloon will drift lower as it loses lift. To compensate, any balloon including human occupants should also have plant life to photosynthesize the CO2 back into oxygen.

I do not know the rates of breathing and rates of photosynthesis to model the required amount of plant life to compensate for an average human's rate of breathing.

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#7 2007-06-10 21:17:23

SpaceNut
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From: New Hampshire
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Posts: 15,823

Re: Given the recent rennaissance in Venutian Cloud Cities here

Ask and here it is Advanced Life Support Systems Integration Test Bed The Greenhouse Effect air from plants

phase1.gif

So far, ALSP has conducted three manned experiments in sealed chambers to test the efficiency of regenerative plant-based and chemical systems. During Phase I of the program, conducted in July 1995, scientist Nigel Packham lived in a 7.2- meter-long chamber in JSC's Building 7, which also houses the Plant Growth Laboratory. The chamber was divided into two compartments, a 4.2-meter plant-growth compartment and a 3.0-meter airlock chamber used for Packham's living quarters. By separating the chambers, scientists were able to monitor and maintain optimal oxygen and carbon dioxide levels in the plant and human compartments.

http://oregonstate.edu/~atwaterj/alss.htm

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#8 2007-06-11 18:15:22

X
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From: Alabama
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Probably going off on a forum inappropriate tangent here, but while the pro-Venus folks almost had me convinced I'm starting to dought it now.  A sphere with a diameter of 1 km would only be able to lift 366.5Mkg.  Maybe I'm mistaken about how much stuff weighs, but once you start putting in some homes, some machinery, some food production, and other stuff that doesn't seem like it'd be very much.  But like I said I'm not sure how much stuff weighs.

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#9 2007-06-12 07:04:28

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Oh I see, you're going for the "designers are idiots because that's the only way I can come up with a far-fetched disaster scenario so I can doomsay".

No, I am going for: "What a good idea. Let us launch and land rockets on the balloons. What could possibly go wrong?"

Have you looked at the size of rockets here on earth? Well.. take another look, since you would need them to be the same size. If the “designers” are so infallible, how come they explode so frequently? Let me guess.. this is part of my “far-fetched disaster scenarios”.. Unless you know how to do it better in which case I think there will be people lining up to pay you the big bucks.. but wait, since the balloons are so safe this would not really be a problem.. if anything else fails, you simply float to the ground. But, why do I have a feeling this might not be such a good idea on the Venus.

And all of this to do what.. so you could build balloons and live on them? If you want to live "near" (floating is near the surface, right?), why not “float” a little higher, with enough speed to not fall to the ground (also known as “low Venus orbit”). What is on the Venus, that you could not get anywhere else with a lot less effort. Even 0,9 g can be easily created with large rotating space habitat.

Venus would be nice place to live on if you striped all of the atmosphere from it and cool it down quite a bit. Until then the first question you would get asked on Venus would be: “Would you like a nice therapeutic swim in a molten lead bath?”

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#10 2007-06-15 21:40:42

samy
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From: Turku, Finland
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Have you looked at the size of rockets here on earth? Well.. take another look, since you would need them to be the same size. If the “designers” are so infallible, how come they explode so frequently?

Because rocket technology is not yet as mature as balloon technology is. You cannot discredit the safety of balloon technology by dragging in another tech and saying, "look how unsafe this entirely unrelated technology is!"

And all of this to do what.. so you could build balloons and live on them? If you want to live "near" (floating is near the surface, right?), why not “float” a little higher, with enough speed to not fall to the ground (also known as “low Venus orbit”). What is on the Venus, that you could not get anywhere else with a lot less effort.

Livable temperature. Livable pressure. Easy access to oxygen, carbon and nitrogen. On a space station, every single kilogram of oxygen or nitrogen (or anything else) that you need will need to be imported for a high price out of a gravity well. If you want to "live off the land", it's usually smart to pick a land that actually *has* some resources. The livable temperature and pressure of Venus mean that systems failures will have much less drastic results. Having a space station suddenly exposed to absolute zero vacuum due to hull breach will do a lot more damage than having a cloud city suddenly exposed to 50C temperature and 1 bar pressure due to hull breach.

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#11 2007-06-16 11:42:33

dicktice
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Right on, samy! When you consider the so-called Earthlike planets being discovered orbiting other stars, they appear to be considerably less inviting than Venus. But they're being considered as potential objectives for interstellar expeditions. We'll settle wherever we can in space: on or about planets, moons, and rotating space-colonies habitats ... so long as resources are accessible.

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#12 2007-06-24 11:32:08

RobS
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Well, no one is considering interstellar expeditions to earthlike planets outside our solar system. By the time we can consider an actual expedition, we'll have found much nicer places to visit.

It was noted earlier that balloons on earth are perfectly safe, but they have one difference with Venus balloons; they can come down. A Venus balloon can NEVER come down. It would have to be inflated at altitude, receive resupply at altitude, repaired at altitude. . . everything. That is several orders of magnitude more difficult, especially when you consider that you have to dock what is essentially a space shuttle or an Apollo capsule or something like that to it in mid air with 100% reliability.

Not easy.

It will be a hundred times easier to study Venus robotically from orbit. A floating or flying robotic post might make sense. An aircraft like Helios with inflatable wings and high efficiency solar panels could fly for many years without any repairs needed. It could serve as a half-way station for Venus sample return missions, with little battery-powered robotic planes to shoot down to the surface and pick up samples, then return before they get overheated, and a two-stage expendible orbital vehicle built into it, slowly making methane and oxygen from hydrogen (from Earth or from sulphuric acid in the aid) and carbon dioxide. A flying or floating robotic outpost makes sense, also, because when it fails after ten or fifteen years, it crashes to the surface and melts, and no one is killed.

                     -- RobS

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#13 2007-06-27 12:36:07

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Have you looked at the size of rockets here on earth? Well.. take another look, since you would need them to be the same size. If the “designers” are so infallible, how come they explode so frequently?

Because rocket technology is not yet as mature as balloon technology is. You cannot discredit the safety of balloon technology by dragging in another tech and saying, "look how unsafe this entirely unrelated technology is!"

You missed the point. You would NEED rockets to get to/from your cloud city. Or if you can make high thrust nuclear rocket you can also use it (it would still be large). In any case it would have to be 100% reliable. If you fail you “land” on a 90 atmosphere, 740 K surface.

Livable temperature. Livable pressure.

If you have a “hull breach” you would still die, since there is no Oxygen there.

Easy access to oxygen, carbon and nitrogen.

What about every other element?

On a space station, every single kilogram of oxygen or nitrogen (or anything else) that you need will need to be imported for a high price out of a gravity well.

Unless it is already out of a gravity well.. maybe in the form of big rocks of dirt and ice we call asteroids?

If you want to "live off the land", it's usually smart to pick a land that actually *has* some resources.

Floating cloud city is hardly something I would call land. You would always be weight limited (to heavy and you fall too deep). You would have to get everything else from “inferno” or from large delta-v outside sources. Besides gasses there is nothing else there. You can get the same gasses elsewhere (anywhere).

The livable temperature and pressure of Venus mean that systems failures will have much less drastic results.

Unless those failures result in having your balloon descending/ascending in the atmosphere, that is..

Having a space station suddenly exposed to absolute zero vacuum due to hull breach will do a lot more damage than having a cloud city suddenly exposed to 50C temperature and 1 bar pressure due to hull breach.

Actually vacuum is pretty benign. If part of a space station is breached, you seal it off, fix the problem (plug the hole), and after that you can use that part of the station again without any problems.

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#14 2007-06-27 19:40:33

X
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Why not simply detach your spaceport from the city?  That would eliminate much of the danger of having a catastrophic accident involving spacecraft.  Casualties would be limited to those working on the spaceport ballon at the time and those on the spacecraft.  Have warehouses on site to store things entering and leaving, and ferry things to and from the spaceport with whatever craft is used for cargo transportation.

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#15 2007-06-27 19:48:58

X
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Besides gasses there is nothing else there. You can get the same gasses elsewhere (anywhere).

This is something I've wrestled with in the past.  However, it seems to me that the vast majority of human expansion hasn't been driven by that much of a realistic economic incentive.  Folks mostly go places because there's land free of occupation.  That was the main selling point of Greenland and Vinland to Vikings in Iceland.  Maybe it isn't a tenable economic model anymore, but most of the people in history seem to have moved places with their only concern being whether or not they could get enough for their family to live on there not whether or not they'd have some advantageous place in the world economy.

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#16 2007-06-28 12:13:36

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Why not simply detach your spaceport from the city?  That would eliminate much of the danger of having a catastrophic accident involving spacecraft.

The danger for people onboard the rockets would be the same.

You would reduce "collateral damage" for the people on the other clouds, but the question still remains why would you want to risk rocket landings and takeoffs from such a dangerous place, if the alternative (rotating city 500 km higher) is so much safer. Any problem in orbit would cause you to simply abort the docking and try again later. Abort on the Venus would be much more trickier, since the rocket is heavier then air and would fall to the surface (air friction).

However, it seems to me that the vast majority of human expansion hasn't been driven by that much of a realistic economic incentive. Folks mostly go places because there's land free of occupation.

Actually the opposite is true. Almost all of the vast majority of human expansion was driven by some kind of economic incentive.

Folks mostly go places because there's land free of occupation.

I would call this “political propaganda”. The Irish went to US because the potatoes failed. The Mexicans go to US because they hope for better living conditions (if not for them – for their children).

That was the main selling point of Greenland and Vinland to Vikings in Iceland.

Vikings went to Greenland simply because there was not enough land where they were born to feed themselves. Who goes and who stays is “decided” by those in power. Those that have barely enough land (food) to feed themselves don’t want to share that with others (they would all die). When you are faced with an option “go with me somewhere you will survive” or “die from hunger” any danger soon becomes quite acceptable.

Maybe it isn't a tenable economic model anymore, but most of the people in history seem to have moved places with their only concern being whether or not they could get enough for their family to live on there not whether or not they'd have some advantageous place in the world economy.

Advantageous place in the world economy is important, because it allows you to trade something to get something else in return. Arabs have oil, and they don’t have to worry about what they will eat. Sub-Saharans worry about that since they don’t have the oil. Even if you suddenly banned the food exports to the Arabs they could find solutions with money (build lots of greenhouses in the desert?), while those without money don’t have this option (notice the lack of greenhouses in Sub-Sahara).. To simplify: How you live is dependant on how much it costs to live. The cost is basically how much work something needs (based on supply and demand). The price reflects that. A 2 kg shoping bag of food is cheaper then a 2 kg shoping bag with laptop in it. If you can't make anything yourself then you must buy it from someone else. But you must also sell something yourself to get the money to buy those things.

Why is that important in any space colonization? Ok, first of all.. where could people live (and I am not talking about 6 people, 3 years stays)?

A colony on a planet or a moon seems like an obvious choice, but would Moons gravity (0,17 g) or even Mars gravity (0.38 g) be enough? I doubt it. The Venus (0,9 g) would be ok, but the place is an inferno. The space stations could make any gravity simply by choosing how fast it would rotate, so this would be ok also. Which would be cheaper?

a) Large rugged cylinder made from 1 m thick slabs of iron from the iron asteroids (melted by the sun) and slowly delivered to high orbit to be used as a space dock. Built as large as needed (capable of housing millions of people if needed) and made to last for centuries. Safe with a lot of space, more accessible (high delta-v + low thrust), easy to build and maintain,..

b) Large balloon made from high-tech fabrics, in need of a constant attention, weight limited, small capacity, hard to get to (high delta-v + high thrust), and hard to build..

And you need things cheap to have any hope of them supporting themselves.. grow food first, build laptops later if possible (or export something to Earth so you could pay for those laptops).. While the station could serve as a dock where you would assemble/build spaceships, the cloud city would be as useful as cloud city on earth. And even a "cheap" space station like this would cost A LOT OF MONEY..

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#17 2007-08-28 08:00:12

Terraformer
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From: Lancashire
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Re: Given the recent rennaissance in Venutian Cloud Cities here

What about half-way between orbit and a baloon, perhaps with a back up rocket in case it starts sinking to launch it into orbit.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#18 2007-08-28 15:12:33

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

It's a matter of speed. Either you float (= near zero speed) or you have enough speed to fall but never fall down (= orbital speed).

Half way would be something that would have high speed and therefore high drag, but would not be able to get high enough to get away from it. Kind of like "the worst from the both worlds" thing.

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#19 2007-09-02 11:52:44

Tom Kalbfus
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Atmosphere is a death trap.

Only at certain altitudes, which we can avoid.

One problem and you crash to 90 bar pressure and 460 degrees C surface.

Oh I see, you're going for the "designers are idiots because that's the only way I can come up with a far-fetched disaster scenario so I can doomsay".

Any *intelligent* designer will include redundancies, so any *one* problem won't end up crashing the float.

You could also say that "one problem and a terrestrial hot air balloon falls to the ground from 1km altitude". You know what? People still go up in terrestrial hot air balloons. When's the last time you've heard of a balloon accident on Earth? Here's a hint: they're very rare. You know why? Because this is proven, well understood technology that our civilization has mastered to a *very* high level.

The only real problem with terrestrial zeppelins was hydrogen use (Hindenburg), but since hydrogen would not be used on Venus, even that problem is eliminated.

This is very well understood, mastered, functional technology. Humans can do balloons *very* well.

It is safe to use hydrogen on Venus as the only thing that makes hydrogen dangerous to use on Earth is the presence of oxygen in the atmosphere and Venus doesn't have any.

I think Venus might be an interesting place to send prisoners and convicts with no chance of parole, it is a hellish planet after all, and anyone who's left suspended in the upper atmosphere is not coming home again. We just don't have the technology to get out of Venus's atmosphere once in there. Venus has almost the gravity of Earth and just look at what sort of vehicles we require to get into orbit.

Well perhaps a varient on SpaceShipTwo could get people into space temporarily before falling back again.

To get out of Venus's atmosphere, you need a ShaceShipTwo and then something to sweep down and meet it on its suborbital arc to provide the final boost to orbit. That would have to be how a manned Venus mission would be done if a return to Earth is planned. Things would have to be coordinated just right though. I doubt there would be another SpaceShipTwo avaliable once its propellent is exhausted and the mothership misses.

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#20 2007-09-10 11:00:15

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

And the cost for such prison would be..

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#21 2007-09-29 16:11:12

Tom Kalbfus
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Re: Given the recent rennaissance in Venutian Cloud Cities here

And the cost for such prison would be..

Probably about as much as setting up a Mars colony. Getting people to Venus is hard, bringing them back, that's harder.

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#22 2007-09-30 13:45:25

neviden
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Re: Given the recent rennaissance in Venutian Cloud Cities here

What kind of a prisoner would have to be sent to $500B Venus cloud city instead to $100M Supermax on Earth. Superman, maybe?

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#23 2007-10-01 06:31:43

Antius
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From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Given the recent rennaissance in Venutian Cloud Cities here

What kind of a prisoner would have to be sent to $500B Venus cloud city instead to $100M Supermax on Earth. Superman, maybe?

Good question.  The main stumbling block with all these technofantasy discussions on Venus cloud cities is why anyone in their right mind would want to go there.  Most well-meaning people spend their entire lives trying to avoid going to hell.

Another problem as far as I can see is that a Venus colony could not export anything meaningful to pay for itself and transporting supplies to a floating Venus colony would be difficult.  You might as well talk about colonising the atmosphere of Jupiter or Saturn.  Both concepts are similarly impractical.  For the foreseeable future, the most practical and desirable off-world locations will be the following, in the following order of preference:

1) Floating colonies in Near Earth space (supplied from the Earth, Moon and Near earth asteroids)

2) The Lunar surface, supplied from Earth and Near Earth space.

3) Mars, supplied from Earth and Near Earth space.

Near Earth space will remain the focus of human activity in space for at least the next 100 years, and 99% of people living in space will reside there.  There will be some (relatively minor) activity on the surface of the moon (mostly associated with mining), regular trips to asteroids (though little permanent residence) and a few expeditions to Mars.  No one will go to Venus, simply because there is no good reason to.  Automated probes will make any scientific observations of the atmosphere far more cheaply and safely.  The outer planets are unlikely to be visited by human beings for a long time to come, for the simple reason that robots can accomplish all of the science at a fraction of the cost and none of the outer planet moons will be prime candidates for colonisation.

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#24 2007-10-01 09:07:53

neviden
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Registered: 2004-05-06
Posts: 99

Re: Given the recent rennaissance in Venutian Cloud Cities here

I agree. But I would not call them floating colonies, since they would not float on anything. They will be either small modular orbiting stations like ISS/Mir in LEO or maybe even rotating space stations built in HEO from NEO resources if we will invest enough money in space manufacturing/transportation.

Rotating space station around Venus would be a bargain (to build and maintain) compared to a floating cloud city in Venus atmosphere.

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#25 2007-10-17 14:16:19

JoshNH4H
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From: Pullman, WA
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Re: Given the recent rennaissance in Venutian Cloud Cities here

Why b go to venus at all?  It seems like trying to force something that wouldn't work.  There's no reason to land on the planet (except scientifically) and for orbit, EO or SO seems far more economical.


-Josh

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