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jonfr
2010-Jan-16, 11:28 PM
Alright, here is the deal. I have nothing important to do in the long run. So I did think that it was smart for me to use the time into do something really useful for mankind. This useful thing that I did come up with is terraforming the planet Venus, as I look at Mars as a cold (dead) planet in all the sense of the word.

First things first. This is not a joke, in time I will setup a web page for this. But for the time being I need to do a scientific check-up on Venus and see what problems I have to deal with this project.

I got some of the answers, but nearly all of them. I already know what the atmosphere of Venus is made out of. But I do not know why (since nobody knows) it did go this hellish way that it is today.

Basic facts.

Atmosphere of Venus. Data is from Wikipedia! See source link.

Composition
~96.5% Carbon dioxide
~3.5% Nitrogen
0.015% Sulfur dioxide
0.007% Argon
0.002% Water vapor
0.001 7% Carbon monoxide
0.001 2% Helium
0.000 7% Neon
trace Carbonyl sulfide
trace Hydrogen chloride
trace Hydrogen fluoride

Surface pressure 93 bar (9.3 MPa)

Geology.

Similar to Earth. Possibility of volcanic activity.

The goal of this project is to make Venus similar to Earth in terms of atmosphere. Venus will never have glaciers I would think, given how close it is to the sun.

Earth

Composition
78.08% nitrogen (N2)
20.95% oxygen (O2)
0.93% argon
0.038% carbon dioxide
About 1% water vapor (varies with climate)[8]

Surface pressure 101.3 kPa (MSL)
-

I however am going to need some long term help with this project, something organised and well funded with time. For those in doubt, I am not running a scam here. This might well take me over 30 - 50 year to finish from start to end, but then it just have to be that way. Doubts can be met, but I want real arguments, nothing else. As this is the same thing that I demand of my self in this type of matters when I am not running an idea or a hypothesis.

I believe that this can be done, it is just matter of how and when.

Sources.

Venus (http://en.wikipedia.org/wiki/Venus) (Wiki)
Venus (http://www.nasa.gov/worldbook/venus_worldbook.html) (NASA)
Earth (http://en.wikipedia.org/wiki/Earth) (Wiki)

kleindoofy
2010-Jan-16, 11:36 PM
... I however am going to need some long term help with this project ...
That's the understatement of the decade.


... This might well take me over 30 - 50 year to finish from start to end ...
That's the understatement of the century.

neilzero
2010-Jan-17, 12:28 AM
I'll assume Jonfr meant 30 to 50 years to complete the engineering proposal and he realizes that an Earth like Venus is many centuries in our future, if ever. There is also a layer of sulpher trioxide in water = sulphuric acid droplets = clouds at mid altitudes, which will descend if we cool Venus. There is at least one rather long and detailed thread on terraforming Venus here at Baut forum and at www.space.com forums. A 100 million square kilometer sun shade = statite can cool Venus to about zero c in about 100 years, but lots of problems will remain and Venus will reheat quickly with smaller sun shades, unless we dispose of nearly all the carbon dioxide. In theory, we can bury the carbon, but then we will have way too much oxygen, but not enough water. The surface air pressure of Venus is about 90 times Earth's sealevel pressure. Worse if we lower the "air" pressure, Venus may out gas lots more gas and vapor.
Some experts think Earth had a thick carbon dioxide CO2 atmosphere about 4 billion years ago, but coral and other sea creatures converted the carbon dioxide to limestone = CaCO3 = calcium carbonate. Neil

cjameshuff
2010-Jan-17, 02:07 AM
You dismiss Mars as cold and dead, but it'd be far easier to terraform than Venus...you wouldn't need to move nearly as much atmosphere or add any water. It would be no less pointless and wasteful, though...terraforming is ridiculously inefficient, and actively destroys valuable natural resources.

Venus has a high-density atmosphere with constant wind. Deep within the atmosphere and on the ground, this is a valuable energy source, with much higher power density at a given windspeed than Earthly wind power, while higher altitudes have plentiful solar power as well. The atmosphere itself can be used as a feedstock for plants and chemical industry, producing food, polymers, graphite and carbon fiber/nanotube based materials, rocket fuel, etc. And while Venus is very dry relative to Earth or Mars, you only need oceans of water if you're terraforming...it has plenty of water for human habitats and industry.

While the surface is hot (~460 C), the high-density atmosphere will be very effective at removing heat from hotter objects...it makes an excellent heat sink, despite its high temperature. "Air-cooled" RTGs will be useful power sources, and machinery will have little trouble keeping its temperature close to ambient...overheating may actually be less of a concern for those components that don't need active cooling to temperatures below ambient. You could also make use of technologies like molten salt batteries that are little used on Earth due to the need for lengthy warmup times or the power requirements of keeping them hot...they will operate quite nicely at ambient temperature on Venus.

In terraforming, you're destroying these useful attributes (requiring you to rework all the infrastructure dependent on them which you installed on the planet while terraforming it) and turning Venus into a poor imitation of Earth, one which takes constant effort to maintain and likely would never sustain a human unprotected for any length of time without great health risks. You do all this at great expense, tying down some resources and outright destroying others when you could be doing any number of vastly more productive things instead. It would be far more effective for us to adapt to and exploit the environment of Venus than try to make it Earthlike.

neilzero
2010-Jan-17, 02:43 AM
Hi cjamrshuff: That is a very thoughtful response. I think I agree, we can start building a Dyson swarm with about the effort it would take to make Venus almost Earth like. Perhaps jonfr has some fresh ideas about Venus. Neil

neilzero
2010-Jan-17, 03:31 AM
Venus has some other rather unique problems, such as no moon, a day more than 200 times longer than Earth or Mars, very slow rotation on it's axis, essentially no magnetic field, negligible tilt on it's axis, about 2/3 more solar energy, per square meter. A high percentage of the solar energy is reflected back into space, and terraforming will make Venus less reflective and thus hard to keep the surface cool. Likely no plate tectonics, but it may have resurfacing lava flow.
A big plus is about 90% of the surface gravity of Earth. A 40 million square mile statite could simulate approximately a 24 hour day for some parts of Venus a few months out of a Venus year and an occasional imitation moon, with a much larger apparent size than Earth's moon. For maximum photosynthesis, the statite sun shade should be transparent to the wavelengths of light most useful for photosynthesis. Neil

jonfr
2010-Jan-17, 07:30 AM
neilzero, I estimate that if everything goes according to plan (when that is ready) this progress is going to take 30 - 50 years. It might not finish in my life time until it gets habitable. But the progress cannot (fixed at 19th January 2010) start now without any issues, as there are many technical problems that need to be solved with time and advances in technology.

Venus not having a moon is not the problem that it appears to be. There is also a good chance on using hot spring bacteria to start the terraforming process on Venus, as they can tolerate the heat and the nasty environment that is on Venus.

I regard Mars as dead planet, as it is harder to warm a planet like Mars then it is cool down a planet like Venus. Mars also has the problem of loosing it atmosphere and it is not getting replenished from volcano activity. Like Venus appears to be, at least there are clues in that direction.

Was spot on Venus a volcano? (http://www.scientificamerican.com/article.cfm?id=was-spot-on-venus-a-volcano-2009-07)

With more water, tectonic progress is likely to start on it's own. At least that is how it works on Earth, as water works on rock as a oil works on a car engine.

cjameshuff, I do not think it is going to be easier to terraform Mars. Given this facts about it's atmosphere.

Surface pressure 0.6–1.0 kPa

Composition

95.72% Carbon dioxide
2.7% Nitrogen
1.6% Argon
0.2% Oxygen
0.07% Carbon monoxide
0.03% Water vapor
0.01% Nitric oxide
2.5 ppm Neon
300 ppb Krypton
130 ppb Formaldehyde
80 ppb Xenon
30 ppb Ozone
10 ppb Methane

Mars is also smaller then Earth, and that comes with it's own problems. But you will see that Mars has almost as same amount of Co2 as Venus, but is yet cold with main temperature around -30C.

Source, Mars (http://en.wikipedia.org/wiki/Mars) (Wiki)

This all takes time, but I am sure that we are going to speak about this here and somewhere else for a long time to come. :)

cjameshuff
2010-Jan-17, 08:26 AM
I regard Mars as dead planet, as it is harder to warm a planet like Mars then it is cool down a planet like Venus.

What possible reason do you have to claim this?



Mars also has the problem of loosing it atmosphere and it is not getting replenished from volcano activity.

This is not even remotely a problem considering that you added an entire atmosphere in the first place. This involves adding a small fraction of the amount of atmosphere that would need to be removed from Venus during terraforming. If you're capable of that, maintaining the atmosphere is peanuts.



cjameshuff, I do not think it is going to be easier to terraform Mars. Given this facts about it's atmosphere.

Surface pressure 0.6–1.0 kPa

Composition

95.72% Carbon dioxide
2.7% Nitrogen
...snip...

Mars is also smaller then Earth, and that comes with it's own problems. But you will see that Mars has almost as same amount of Co2 as Venus, but is yet cold with main temperature around -30C.

It has almost the same composition as Venus. It certainly doesn't have "almost the same amount of CO2"...surface atmospheric pressure on Venus is about 16000 times that on Mars. The small size is actually a bonus here...an atmosphere with 1 atmosphere of surface pressure will be considerably deeper than on Earth, and be better at retaining and distributing heat, on top of making an even better radiation shield than Earth's atmosphere. As for temperature...the surface of Mars routinely gets within a few dozen Kelvin of the freezing point of water, while the surface of Venus is several hundred Kelvin above the boiling point. Mars will warm and Venus will cool as you make their atmospheres more Earthlike, but Venus has much further to go.

Mars is a vastly more suitable target for terraforming. It has substantial amounts of water and CO2, and addition of nitrogen would probably be enough to allow some plants to grow there (after things thawed out a bit and a water cycle started again, that is). It would take enormous quantities of nitrogen, but it wouldn't take as much nitrogen as you would need to remove from Venus. And removing the nitrogen from Venus is a minor problem compared to removing the CO2 and supplying water...

Terraforming Mars would be far faster and cheaper than terraforming Venus, but again, you're devoting massive resources to developing and maintaining a poor imitation of Earth. Better to mine the icecaps and glaciers (which would be destroyed in the process of terraforming) for volatiles to use in polymer and rocket fuel manufacture and food production, leave the atmosphere thin so it doesn't interfere so much with launches or solar collectors, or support much in the way of severe weather, and construct enclosed domes and underground habitats that could be made far more comfortable than the surface, and be inhabitable without having to wait centuries...if you want to live on the surface instead of an orbital habitat, that is.

jonfr
2010-Jan-17, 08:54 AM
Question asked.

What possible reason do you have to claim this?

Most of Mars atmosphere is actually frozen in its soil as water. However, research has shown that Mars thin atmosphere is due to the planet size. As from NASA.

Nov. 21, 2008: Researchers have found new evidence that the atmosphere of Mars is being stripped away by solar wind. It's not a gently continuous erosion, but rather a ripping process in which chunks of Martian air detach themselves from the planet and tumble into deep space. This surprising mechanism could help solve a longstanding mystery about the Red Planet.

"It helps explain why Mars has so little air," says David Brain of UC Berkeley, who presented the findings at the 2008 Huntsville Plasma Workshop on October 27th.

[...]

Solar Wind Rips Up Martian Atmosphere (http://science.nasa.gov/headlines/y2008/21nov_plasmoids.htm)

The status of magnetic fields on Mars is also a other problem. Given how fractured they are, it appears that the Mars core is actually shutting down (cooling), or might already been cold for most part. But that does not necessary mean it is solid like rock.

Mars Core Squishy, Goes with the Tidal Flow (http://www.space.com/scienceastronomy/mars_core_030306.html)
Mars' Gooey Core is Freezing (http://www.space.com/scienceastronomy/070531_mars_core.html)

I want to note that I do not know everything about Mars or Venus. But in the time frame of next two to three years am going to read up on the planets when I have time. But in the mean time, I will have gap in my knowledge in regards to Mars and Venus.

Here is some interesting article about Venus core. It is from 1997 so it might be outdated.

VENUS: MAGNETIC FIELD AND MAGNETOSPHERE (http://dawn.ucla.edu/personnel/russell/papers/venus_mag/)

When terraforming Venus it is not going to add atmosphere to the planet. The idea is to convert the current atmosphere to a good healthy atmosphere. However, that process brings its own problems. The main problem being, how to convert the atmosphere and with what.

There is a good chance that the water that exist on Venus is actually trapped in the rocks of the planet. Given other research that have shown that to be the case on Earth.

There are two ways that water can be included in rock. It can exist as a solid, liquid or gas trapped in pore spaces (holes) in the rock. Water molecules can also be trapped and included as part of the crystal structure of the rock.

How can water be chemically trapped in rocks? (http://curious.astro.cornell.edu/question.php?number=423)

Van Rijn
2010-Jan-17, 09:32 AM
Here's a link to a (long!) BAUT thread that discussed the issues of terraforming Venus.

http://www.bautforum.com/life-space/59971-making-venus-livable.html

There are some references in the thread to useful books, online articles, etc.

I doubt there can be much added here in Q&A to what was already discussed there.

Short version: We certainly don't have the technology now, and can only speculate. Venus looks like a much more difficult terraforming target than Mars, though Mars would be very difficult too.

neilzero
2010-Jan-17, 10:42 AM
Thank you Van Rijn: My guess is we do not know which is easier to terraform until we complete the details of the engineering plans for Mars and Venus. At present most of the engineering is untested hypothesis. Likely more money has been spent on Mars than on Venus as it appears Mars will be easier at present. Also reasonable goals for neither planet are firm. As far as I know no one has done a serious analysis of my plan to concentrate on the the two polar regions of Venus and leave the rest of the surface of Venus at approximately 460 c. I certainly do not claim to have the expertise to do a detailed engineering analysis of any engineering plans for Venus or Mars. Neil

jonfr
2010-Jan-17, 10:58 AM
Van Rijn, thanks for the link. I will look at it and check if there is anything useful in there. This is Q&A, but this is also me asking for help to finish this project or at least start it. If I don't get a support from people on the street. I am going to take my idea to ESA or NASA when the time comes.

neilzero, There is a lot of researches needed into both Venus and Mars before they can be terraformed as you point out, or even before we know how how that can be done and what technology is needed. But we all need to start somewhere, and in my case this was the best place to start this project.

neilzero
2010-Jan-17, 12:32 PM
Hi Jonfr: I agree we can work many engineering plans in parallel starting now. It will be a labor of love as it is unlikely anyone with deep pockets will supply large amounts of money in this century.
The first step in my plan is the snow = dust fence about 1000 kilometers long. I suppose a crash program could instal the first kilometer in 2012. What is the first step in your version of making Venus livable?
I agree the importance of Earth's moon is likely seriously over rated, and hardly applicable to Venus at all.
To use hot spring bacteria on the surface of Venus, we first need to lower the temperature (or raise the pressure) so the water is liquid. As far as I know, no live bacteria (or other creatures) have been documented above about 150 c Expensive genetic engineering can possibly produce creatures that can function at 260 c, but 460 c is a long shot. The upper atmosphere of Venus is presently much cooler, so perhaps the bacteria can make limestone and algae can make oxygen 100 kilometers above the surface, but either need a sizable supply of nutrients and water. Obviously the bacteria need a source of calcium ions = CaO lifted from the surface of Venus with kites or balloons perhaps?
Earth may have ten times more water in the crust than it has in all the oceans. We can make many cubic kilometers of water on Venus, if we import a billion metric tons of hydrogen from one of the gas giant planets and we can find a catalyst that frees the carbon in the carbon dioxide. Since most of the water escapes rock that is heated to 460 c, Venus likely has much less water in the crust where the average temperature may be more than 1000 c. Has anyone seen speculation on the nature of the crust of Venus?
I agree with cjameshuff, that the percentage of carbon dioxide is almost the same for Mars and Venus is close to irrelevant. If 3.5% nitrogen is correct, it may not be necessary to remove any nitrogen from Venus = I dont think exactly like Earth is necessary = some genetic modification of humans is likely practical, if not ethical.
I'm sure jonfr is aware that some learned papers are rejected later by the mainstream even when peer reviewed in prestigious journals. Does anyone know the status of the four links that Jonfr supplied?
The main reason Mars is much colder than Venus is, Mars gets less than half as much solar energy per square meter as Venus. Clearly orbital habitats, underground habitats and domes have problems that may not have acceptable solutions for Mars, Mercury, the moon, asteroids or comets. Neil

neilzero
2010-Jan-17, 02:02 PM
~Assuming Fogg has it correct, here is how long it takes to freeze the atmosphere of Venus~ Martin J. Fogg goes into this in some detail in his book, "Terraforming." According to him, with a complete cutoff of sunlight, it would take a total of about 200 years in 5 stages. The first period, where the pressure would stay roughly stable but the temperature would drop from around 460 c to 31C, would take 58 years. Then CO2 rain would begin to fall, forming oceans and the pressure would drop, but the temperature would be stable for 27 years. Then the temperature and pressure would fall for 97 years with the temperature dropping to -56C. Then the pressure (now down to 7 atmospheres) and the temperature would stay stable for 7 years, while the oceans freeze to dry ice. Finally, in another 9 years, the rest of the CO2 would freeze out, leaving mostly nitrogen, and the temperature would drop to -81C. The remaining atmosphere would still be substantially thicker than earth's. They don't take the last possible stage (dealing with the nitrogen). ~It appears that the 27 years can be extended at about 31 c by letting in just the right amount of sunlight, but liquid carbon dioxide oceans is not very Earth like but plants might thrive and make lots of oxygen. I think water and lots of other stuff dissolve in liquid carbon dioxide at about 31 degrees. You can find more info by putting terraform Venus in the google search for bautforum.com Neil~

neilzero
2010-Jan-17, 02:13 PM
Following are my comments of 11 weeks ago: Most terraforming experts are of the opinion that Mars can keep an atmosphere for a million years, but not much longer without replenishing. Hydrogen/water replenishing may be automatic by comet collision. Increasing the average surface temperature of Mars by 20 degrees c = 36 degrees f will not increase the atmosphere loss by much, but that is warm enough for most plants, only at low elevations near the equator, so it will take a million years for plants to reduce the present carbon dioxide significantly. CFCs and other green house gases can be manufactured on the surface of Mars and released into the atmosphere to warm Mars, perhaps 5 degrees c = 9 degrees f. My guess is more is not practical as the power of green house gases has been seriously exaggerated and some green house gases will impede plant growth even in low concentrations. There are some plant varieties that can subsist in the present Mars atmosphere, which has negligible free oxygen, but water, fertilizer and warmer temperatures are needed. I have not heard any believable method for getting significant free oxygen in Mars atmosphere, so it appears oxygen masks for people and animals are the only likely option. The pressure needs to be higher than the present 3 to 6 millibars for humans and most animals and plants, even breathing 98% oxygen. The pressure may eventually increase enough, if we use statites or equivelent moon size mirrors to heat Mars about 20 degrees c. Trace chemicals in the Mars biosphere will have to be removed for healthy plants and animals. In my opinion semi terraforming Mars is almost as costly as semi terraforming the polar regions of Venus. Neil

jonfr
2010-Jan-17, 05:14 PM
The problem with Venus is not necessary the atmosphere it self, it should be relative easy to convert it. The problem with Venus atmosphere is the heat and the wind that comes with it. The main issue would be to let the heat out into space.

This is explained properly here.

Why is it so hot on Venus?

Soviet and American probes have landed at many places on the surface of Venus — and all have reported temperatures above 900° Fahrenheit, day or night. (For comparison, the temperature in an oven broiler is "only" 500°.) Part of the reason for the high heat is that Venus is closer to the Sun than we are — but that's by no means the whole story! Mercury is even closer to the Sun — but its surface is cooler than Venus's. Most of the heat on Venus is due to the peculiar heat-trap its atmosphere provides. (Mercury has no atmosphere to trap heat.)

Venus's massive atmosphere is made mostly of carbon dioxide, which has a peculiar property: it is transparent to visible light, but nearly completely blocks infrared — sometimes called "heat radiation". On Venus, intense sunlight filters through the clouds and heats up the rocks on the surface. Those rocks then "glow" infrared, but the carbon dioxide doesn't allow that infrared to get out. Instead, its energy is trapped in the atmosphere, adding to the heat provided by sunlight.

Ordinary window glass behaves in much the same way on Earth as carbon dioxide does on Venus. Imagine a car parked in a sunny parking lot with the windows rolled up. Sunlight gets through the windows, and warms up the car's interior. The seats then radiate infrared — which is trapped by the windows, because the glass doesn't allow heat radiation to escape easily. In part because of that, heat builds up in the car, and when you open the door... Whew! It's hot. In a way, Venus can be thought of as a car that's been left in a sunny parking lot for four billion years with the windows rolled up.

Source: Exploring Venus (http://astrosociety.net/education/publications/tnl/02/02.html)

I also want to point out ESA web page on this subject, it can be found here: Greenhouse effect, clouds and winds (http://www.esa.int/esaMI/Venus_Express/SEMFPY808BE_0.html)

cjameshuff
2010-Jan-17, 05:33 PM
What possible reason do you have to claim this?

Most of Mars atmosphere is actually frozen in its soil as water. However, research has shown that Mars thin atmosphere is due to the planet size. As from NASA.

Frozen in its caps as CO2 ice, not in its soil as water. This is irrelevant though, there's not enough CO2 there to supply the needed oxygen, and none of the needed nitrogen...that's not frozen away anywhere, it's just not there. And I already explained that if you can import an atmosphere in the first place (which is far easier than removing enough atmosphere from Venus to terraform it), compensating for the losses is trivial. We're talking about loss on timescales of hundreds of millions to billions of years.

Nothing substantial needs to be done to warm up Mars. Adding that atmosphere will cause the planet to retain more heat, leading to the CO2 in those caps sublimating, leading to a nitrogen-CO2 atmosphere and regions with liquid water that some hardy plants could likely survive in. All you need is a bit less nitrogen than you'd have to remove from Venus.



The status of magnetic fields on Mars is also a other problem. Given how fractured they are, it appears that the Mars core is actually shutting down (cooling), or might already been cold for most part. But that does not necessary mean it is solid like rock.

Neither magnetic fields nor an active core are necessary for terraforming. Especially in the case of Mars, where the low surface gravity will lead to an unusually deep atmosphere at a given surface pressure. Earth's atmosphere blocks almost all cosmic radiation, that of a terraformed Mars would be even more effective.



When terraforming Venus it is not going to add atmosphere to the planet. The idea is to convert the current atmosphere to a good healthy atmosphere. However, that process brings its own problems. The main problem being, how to convert the atmosphere and with what.

No, of course you're not going to add atmosphere to Venus! Did I at any point say anything about doing so?
Venus already has 3 times as much nitrogen and 60-70 times too much oxygen combined with carbon as CO2. Venus receives about twice the solar radiation that Earth does, this will be trapped by a thick atmosphere...you may need to remove almost all the nitrogen and create a lower-pressure, mostly-oxygen atmosphere. The 5800 hour long days don't help...

If you drop the terraforming idea and just colonize Venus as it is, you can take advantage of the superrotation of the Venusian atmosphere to give high altitude habitats a "day" of just a few Earth days, which would be far easier to adapt to...just shuttering windows for one false night and using artificial lighting for one false day will give a relatively Earthlike period for those plants/animals that can't adapt. The same winds in the high-density atmosphere make an abundant power source. Venus may be a more suitable target for colonization than Mars. It certainly won't be easier to terraform.



There is a good chance that the water that exist on Venus is actually trapped in the rocks of the planet. Given other research that have shown that to be the case on Earth.

There is very little chance of this being so. The surface rock is hot enough to bake out any water trapped in hydrates, subsurface rock is hotter. Lack of water in the rocks is thought to be one possible reason for its lack of tectonic activity. You'll need to import it. This compares poorly with Mars, which appears to have enough in the form of simple water ice for sizable oceans should it all be thawed.

cjameshuff
2010-Jan-17, 06:17 PM
The problem with Venus is not necessary the atmosphere it self, it should be relative easy to convert it.

If its so easy to "convert" the atmosphere into an Earthlike one, how about explaining your process? Are you thinking that too much oxygen couldn't be a bad thing? Oxygen is toxic in high concentrations, even at 1 atmosphere. The 60+ atmospheres of oxygen that you convert CO2 into would be both deadly and an insane fire hazard for anything living in it. You could sequester a lot as carbonates...this will inevitably create a lot of hydrated rock, further increasing the amount of water you need to import, and is unlikely to sequester enough CO2 to solve the problem.

And then there's the nitrogen. Itself it is pretty inert and harmless, but there's 3 atmospheres or so of it, and it's much harder to convert into solid form. Combined with oxygen and ionizing solar radiation, it'll form nitrogen oxides. A high-pressure CO2/O2/N2 atmosphere with some left over SO2 and a bunch of added H2O, with twice Earth's UV exposure (more before you coax an ozone layer into existence), might produce quite an impressive photochemical smog.



The problem with Venus atmosphere is the heat and the wind that comes with it. The main issue would be to let the heat out into space.

For terraforming, the problem is simply that there's too much of it! I don't know how you keep missing this point. The current atmosphere of Mars can basically be ignored as far as terraforming goes, you'll need to import a new one. Terraforming Venus will require exporting or somehow sequestering many atmospheres worth of nitrogen and CO2, or at least O2.

The wind is the reason the daytime temperatures aren't even higher than they are...they distribute heat around the planet. If your terraforming stops the wind, what are you going to do to avoid things baking during the day and freezing during the night?

EDG
2010-Jan-17, 10:12 PM
~Assuming Fogg has it correct, here is how long it takes to freeze the atmosphere of Venus~ Martin J. Fogg goes into this in some detail in his book, "Terraforming." According to him, with a complete cutoff of sunlight, it would take a total of about 200 years in 5 stages. The first period, where the pressure would stay roughly stable but the temperature would drop from around 460 c to 31C, would take 58 years. Then CO2 rain would begin to fall, forming oceans and the pressure would drop, but the temperature would be stable for 27 years. Then the temperature and pressure would fall for 97 years with the temperature dropping to -56C. Then the pressure (now down to 7 atmospheres) and the temperature would stay stable for 7 years, while the oceans freeze to dry ice. Finally, in another 9 years, the rest of the CO2 would freeze out, leaving mostly nitrogen, and the temperature would drop to -81C. The remaining atmosphere would still be substantially thicker than earth's. They don't take the last possible stage (dealing with the nitrogen). ~It appears that the 27 years can be extended at about 31 c by letting in just the right amount of sunlight, but liquid carbon dioxide oceans is not very Earth like but plants might thrive and make lots of oxygen. I think water and lots of other stuff dissolve in liquid carbon dioxide at about 31 degrees. You can find more info by putting terraform Venus in the google search for bautforum.com Neil~

So you put up a huge sunshade, block out the sun at Venus for a few decades, and you're left with a planet surrounded by a thick CO2 ice layer and possibly liquid CO2 oceans... so what are we supposed to do with all that CO2 before we can do anything else with what remains? Seems that it'll take a while to excavate it all and cart it offworld, wouldn't it?

neilzero
2010-Jan-18, 03:19 AM
~Here is my post from last May~ Terraforming requires several heroic technologies. Statite sun shades could block most of the Solar energy reaching Venus. Venus would cool significantly in a few centuries, not a million years, even if we are trying for minus 100 f to make dry ice out of the carbon dioxide. Without sunlight we can not use photosynthesis to convert the carbon dioxide to bio-char and oxygen. Some of the free oxygen would react with the rocks on the surface, but we could have too much free oxygen in the atmosphere by converting as little as 1% of the carbon dioxide.
Venus does not have enough hydrogen to make more than one small shallow ocean, so the water for photosynthesis is a problem. Daily comet impacts interfere with almost everything else we might want to do, unless they are small comets that vaporize completely before reaching the surface, or we can restrict the comet impacts to less than half of Venus = extreme accuracy requirement. Worse sulphuric acid bonds strongly to water, so we would get weak acid instead of free water.
My guess is we should start with perhaps 5% of the area of Venus near the North pole of Venus. It already has one of the tallest mountain ranges on Venus. We surround that area with a snow fence = more correctly a dust fence, more heat tolerant than the plastic dust fences required by EPA for many construction sites. For best results, more than one thousand miles of double fence.
Now we can begin adding algae, water and fertilizer to the narrow band of upper atmosphere, where the temperature is suitable. This is a huge project as much of the stuff we deliver will fall to altitudes which are too hot to grow algae. The sulphuric acid is mostly in a narrow band closer to the surface, so this is not a near term problem. The high altitude winds spiral around the Northern Hemisphere ending in a great polar down draft. As the algae descends it becomes bio-char = algae charcoal. Surface winds near the North pole are toward the equator. The dust fence will deposit the algae charcoal, and other dust just outside the fence. We will need to move the fence as it becomes buried. Over several thousand years the fence location will become a mountain range which will block the rare North bound surface winds allowing the polar plateau to cool. Shortly before the sulphuric acid rain reaches the surface, we will cover the Arctic plateau (perhaps a million square miles) with an impervious coating, so the acid will not sink into the very dry bio-char and dust, This will be very acid mud as the dust continues to arrive with the strong acid. After a few years we will move the statite sunshades so they provide less shade; the rain will stop until we install another impervious layer. We will repeat this several (many?) times until nearly all the sulphuric acid is sequestered inside the growing polar plateau. Now fresh water rain will fall. so we can think agriculture on the higher portions of the polar plateau. The atmosphere is still about 90% carbon dioxide, about 0.3% free oxygen which is optimum for humans at about 80 atmospheres. We will have to genetic engineer the humans, and they will need a prosthesis to remove carbon dioxide from their blood. The algae program can now be reduced, as more than 0.3% oxygen at 80 atmospheres will be a major fire hazard. We sort of terraformed about 5% of Venus.
Advantages are: it took less than one million years. Up to a billion genetically altered humans can live on the surface of Venus. There is a million year supply of sulphuric acid which can be pumped to the surface as needed. New technology and new ideas can terraform more of Venus if that is a good option. The mile plus layer of algae charcoal is good insulation so the internal heat of Venus cannot reach the new surface. The old surface under the center of the Arctic plateau may be as hot as 1000 degrees c. Will the plateau sink due to it's weight? Neil

cjameshuff
2010-Jan-18, 04:30 AM
Even with filters to pass only the desired wavelengths, with that thick CO2 atmosphere, you won't be able to let much sunlight through without overheating the planet...drastically limiting the amount of photosynthesis that could be done. But a more severe problem...



The atmosphere is still about 90% carbon dioxide, about 0.3% free oxygen which is optimum for humans at about 80 atmospheres. We will have to genetic engineer the humans, and they will need a prosthesis to remove carbon dioxide from their blood.

You'll need to do far more than add something to remove CO2 from the bloodstream...you'll need drastic modifications to block the CO2 from ever entering it. I think you underestimate the solubility of CO2 under pressure in water...you're talking about an atmospheric pressure about 10 times that of carbonated water here on Earth, and CO2 will quickly enter the body through the skin and mucous membranes, let alone the lungs, driving the pH of tissues way down. You'll need to seal the body surface with CO2-impermeable layers, concentrate oxygen, push CO2 uphill against an extreme concentration gradient, and probably maintain nitrogen-filled lungs if you aren't replacing them entirely with a mechanical equivalent. This doesn't seem even remotely workable or desirable, particularly when it's so easy in comparison to construct habitats and farms that can support unmodified humans. 1 billion humans...you could probably use that buried char to construct farms and habitats to support far more.

jonfr
2010-Jan-18, 06:27 AM
cjameshuff, I am going to disregard your rant. However you asked me this.

If its so easy to "convert" the atmosphere into an Earthlike one, how about explaining your process?

How can I explain something when I haven't even invented it yet. As I clearly say in first post and other post here this progress is going to need a long term development and innovation. You are just asking question that I cannot answer at this point in time. I might be able to answer it in 10 or 20 years time. But in the meantime, it is a work in progress.

I also want to point out that on Mars there is a lot of frozen water it seems, along side frozen CO2 that forms because of the extreme cold there.

If your terraforming stops the wind, what are you going to do to avoid things baking during the day and freezing during the night?

If we look at the Earth as a model. We clearly see that there would not bee any such problem. It is also clear that terraformed Venus would be really warm, do to how close it is to the sun.

Now, the ESA web page (link above) clearly says that temperature in the higher layers of the Venus atmosphere is around 15C. That is good for various bacteria to grow and take advantage of the composition of the Venus atmosphere. If that can be used, it can be a great starting point, however that is going to need research and development like anything else in regards to this type of project.

Data sources:

Lots of Pure Water Ice at Mars North Pole (http://www.universetoday.com/2009/01/20/lots-of-pure-water-ice-at-mars-north-pole/)
Proof! Water Ice Found on Mars (http://www.space.com/scienceastronomy/080620-phoenix-ice-update.html)

Jens
2010-Jan-18, 06:54 AM
cjameshuff, I am going to disregard your rant. However you asked me this.


I don't see why you take that as a rant. He is asking you difficult questions, but you started by saying essentially that you want to make terraforming Venus into a life project, so I think you will have to answer some tough questions since you're proposing something that most of us are going to assume is exceedingly difficult.

jonfr
2010-Jan-18, 07:12 AM
I have clearly stated where this project is and made it obvious what is know and what is not known. This is a rant, because he has decided on his own that this cannot be done. But that is wrong in my opinion. As planetary science is new to mankind, and is going to need more development in the long run as knowledge advances.

I forgot to answer this question.

Are you thinking that too much oxygen couldn't be a bad thing?

At one point in Earth history oxygen levels where around 40%. But that is 20% more then today levels.

I do not think it is wise to move animals to Venus, or at least anything else then plants and such.

Data source.

Planetary science (http://nssdc.gsfc.nasa.gov/planetary/) at NASA.

cjameshuff
2010-Jan-18, 07:17 AM
cjameshuff, I am going to disregard your rant.

Dismissing well-founded objections raised about your proposal as a rant will not make those issues go away.



How can I explain something when I haven't even invented it yet.

You said it'd be easy. I assumed you had a reason to think so.



I also want to point out that on Mars there is a lot of frozen water it seems, along side frozen CO2 that forms because of the extreme cold there.

I know. I've been using that water as an example of one thing that makes Mars easier to terraform. Mars already has enough water for oceans of some size, while most of the water on Venus would probably get bound up in hydrates if you cooled the planet down enough. I have no idea why you're pointing out the presence of water on Mars as though it somehow makes it harder to terraform...



If your terraforming stops the wind, what are you going to do to avoid things baking during the day and freezing during the night?

If we look at the Earth as a model. We clearly see that there would not bee any such problem. It is also clear that terraformed Venus would be really warm, do to how close it is to the sun.

Are you kidding? Venus has a solar day 117 times as long as Earth. Night time lasts 1400 hours. You can not use Earth as a model.

Your posts so far seem to indicate that you have spent little time examining the issues (examples: comparing composition of the Martian and Venusian atmospheres and ignoring the difference in quantity, ignoring the rotation rate of Venus), and are operating from assumptions not based on solid data and understanding. Judging by your response to the issues I raised, it appears you have already decided that you are right and are not interested in any evidence that your goal is less than optimal or even an actively bad idea. Despite asking for input, you are ignoring anything that doesn't agree with your preconceptions. This is not an approach likely to lead to success.

cjameshuff
2010-Jan-18, 07:26 AM
Are you thinking that too much oxygen couldn't be a bad thing?

At one point in Earth history oxygen levels where around 40%. But that is 20% more then today levels.

40% of roughly one atmosphere. Again, you're looking at composition and ignoring quantity...you've been corrected on this before. Percentage is a relative quantity, 40% oxygen at 60 atmospheres would be deadly.

Jens
2010-Jan-18, 07:33 AM
I have clearly stated where this project is and made it oblivious what is know and what is not known.

I know it's a typo, and you meant to say "obvious," but still it almost seems like a Freudian slip. :)


This is a rant, because he has decided on his own that this cannot be done. But that is wrong in my opinion. As planetary science is new to mankind, and is going to need more development in the long run as knowledge advances.


I can think of two main reasons for you to bring up this topic. One is because you are looking for criticism so that you can determine if it is really feasible. In which case, all these comments should be welcomed, even if the person is against the idea. A second is because you are trying to recruit friends or supporters. In which case you should still see this as an exercise in overcoming skepticism. Think of it this way: if you can convince cjameshuff, then it will make it easier to convince everybody else.

jonfr
2010-Jan-18, 07:55 AM
cjameshuff, those "issues" are possible to be least of the problem with terraforming Venus. There are many unknowns in this setup. There are more variables when terraforming a planet then it is to build a spaceship or a satellite.

Your objections are not well founded in my opinion. Well founded objections have facts behind them, something to show that this cannot be done without a doubt. You have not shown any of that. I have pointed out what is already known, as that is the basic for this idea of mine.

On the atmosphere on Earth, it is worth pointing out that the amount of atmosphere on Earth has not changed a lot of 4.6 billion years it has existed. There are at least no data that show otherwise.

Air pressure on Venus also needs to be dropped. But that might be a less problem then it seems, as most of the Co2 would be bound into Calcium or related materials. How that can be done is however a good question and needs to be solved as one of those issues.

Unlike what you claim to know about what I know, and do not know. You are ignoring the obvious, you have no idea how long I have actually spend on this idea of terraforming Venus.

The rotation of Venus is more complex that one might think. First of, it is not only longer as you have pointed out. But it is also counter-clockwise.

Like explained here.

Astronomers have long thought that Venus acquired its unusual 'retrograde' spin when internal friction and turbulence in its atmosphere flipped the planet's rotation axis in the distant past. Now French astronomers argue that chaotic effects could have reversed the planet's spin while its rotation axis stayed put. Alexandre Correia and Jacques Laskar of the CNRS Institute of Celestial Mechanics simulated the rotation of Venus over thousands of millions of years and conclude that it must have followed one of two paths to reach its current state (A Correia and J Laskar 2001 Nature 411 767).

The rotation of rocky planets with dense atmospheres - such as the Earth and Venus - is determined by atmospheric tides, gravitational forces, friction between the mantle and the crust, and the 'obliquity' angle between the planet's equator and the plane of its orbit around the Sun. Accounting for these effects, Correia and Laskar calculated the motion of such planets for a wide range of initial conditions. "We found that, due to the presence of the dense atmosphere, the rotation can only end in four possible spin states", Laskar told PhysicsWeb. Such planets can have either retrograde or 'prograde' rotation - that is, the west-to-east rotation commonplace in the solar system - and their rotation axis may or may not have flipped during its evolution. We know that Venus has retrograde rotation, but has its rotation axis switched?


Source: Doctoring the spin on Venus (http://physicsworld.com/cws/article/news/2661)

I must however point out that I am yet to pull all the data into one dataset on my PC. That might take some time and doing.

Jens, this is a case of spelling check failure. I will fix the error. Thanks. I am always looking for a criticism. However, I want that criticism to be build on something useful and proven, or something that has been disproven. But this a long project. One topic on a internet forum is not going to change its path in the long run.

EDG
2010-Jan-18, 08:41 AM
40% of roughly one atmosphere. Again, you're looking at composition and ignoring quantity...you've been corrected on this before. Percentage is a relative quantity, 40% oxygen at 60 atmospheres would be deadly.

That'd be a ridiculously high oxygen partial pressure ATA as well. In fact I think (if I understand O2 ATA correctly) that'd be way more than enough to make everything spontaneously ignite and combust. IIRC wildfires were prevalent on Earth in the geological past when the O2 ATA rose to about 0.35 atms, but 40% O2 at 60 atms is 24 atms of O2 ATA!

Van Rijn
2010-Jan-18, 08:47 AM
cjameshuff, I am going to disregard your rant. However you asked me this.

If its so easy to "convert" the atmosphere into an Earthlike one, how about explaining your process?

How can I explain something when I haven't even invented it yet. As I clearly say in first post and other post here this progress is going to need a long term development and innovation. You are just asking question that I cannot answer at this point in time. I might be able to answer it in 10 or 20 years time. But in the meantime, it is a work in progress.


The issue is that there are basically two choices: Sequester the CO2 and nitrogen, or eject it from Venus. Unless you plan on breaking the laws of physics, either of those choices would require enormous inputs of mass and energy. You simply aren't going to get out of that.



Now, the ESA web page (link above) clearly says that temperature in the higher layers of the Venus atmosphere is around 15C. That is good for various bacteria to grow and take advantage of the composition of the Venus atmosphere. If that can be used, it can be a great starting point, however that is going to need research and development like anything else in regards to this type of project.


If you want to get something to grow in the Venusian atmosphere, it might be nice. If you want to terraform Venus, that's useless - it doesn't get rid of the atmosphere.

jonfr
2010-Jan-18, 09:01 AM
Van Rijn, if we look at Earth early history. We find that Co2 was high and oxygen was low. So this might not be a big problem once the process has started. However, the problems might be to start the progress in the beginning. I have not yet looked at this in great detail at this time.

Here are few interesting research links on Earth early atmosphere that I could find with google.

Earth's Early Atmosphere (http://www.sciencemag.org/cgi/content/summary/298/5602/2341) (subscription) (2002)

CU Study Shows Early Earth Atmosphere Hydrogen-Rich, Favorable To Life (http://www.colorado.edu/news/releases/2005/156.html) (2005)

Origin of the Earth's Atmosphere (http://www.ux1.eiu.edu/~cfjps/1400/atmos_origin.html)

Now, this might be a good start (top two links). But I am sure that there is more work to be done.

Van Rijn
2010-Jan-18, 09:11 AM
Van Rijn, thanks for the link. I will look at it and check if there is anything useful in there.


Well, this thread is covering much of the same ground that was already covered in that thread, so I'd suggest reading that thread before you continue here.

If you're serious about this idea, I'd also suggest you find a copy of Fogg's Terraforming: Engineering Planetary Environments. It's the closest thing to a serious book on the subject. I'd also suggest Oberg's New Earths. And, read Paul Birch's article (warning: PDF file) "Terraforming Venus Quickly."
(http://www.paulbirch.net/TerraformingVenusQuickly.pdf)
After you read those, you should have a better idea of the scale of the problem.



This is Q&A, but this is also me asking for help to finish this project or at least start it. If I don't get a support from people on the street. I am going to take my idea to ESA or NASA when the time comes.


If your project is writing an updated book on terraforming, I think you have a realistic shot. If you're actually looking at terraforming something, start with Earth. It is undoubtedly orders of magnitude easier, but we seem to have enough problems maintaining our own environment.

Jens
2010-Jan-18, 09:20 AM
If your project is writing an updated book on terraforming, I think you have a realistic shot. If you're actually looking at terraforming something, start with Earth. It is undoubtedly orders of magnitude easier, but we seem to have enough problems maintaining our own environment.

That's a good point, and an interesting question for me. Why is it that many people are keen about terraforming Mars or Venus, but not so much about the earth? I have my suspicions about it. Doing things on earth doesn't allow one to start with a "clean slate." I don't mean this too provocatively, but I think that sometimes among reformers there is a certain desire to start fresh, kind of like a Third Reich thing. I think there is something that attracts people to that. Doing something on Mars doesn't require going through the tortuous process of dealing with actual living people. I say this with a certain amount of self-reflection, because I am a person who designed a constructed language like Esperanto. I'm sure the motivations are shared to some extent.

Van Rijn
2010-Jan-18, 09:24 AM
Van Rijn, if we look at Earth early history. We find that Co2 was high and oxygen was low.


Irrelevant. The total atmospheric CO2 was not comparable to that of Venus.



So this might not be a big problem once the process has started.


Sorry, it is. You would have to deal with the CO2 and nitrogen, and do it in a reasonable time period (I assume you aren't willing to wait millions or billions of years). That requires immense energy and/or mass inputs.

jonfr
2010-Jan-18, 09:34 AM
Van Rijn, This is fact not irrelevant. As it is smart to figure out what natural forces where doing here on Earth in forming the atmosphere. Your claim on the Co2 on early Earth and Venus today is unfounded in my opinion. You at least don't point to any research to support it.

Co2 might be problem. But I do not see how nitrogen is going to be a problem. As on Earth it accounts for 78% of the atmosphere.

The energy issue is not a issue at first look, as we get plenty from the sun it self on Venus. The speeding up the process is going to be a problem that needs to be solved.

Nitrogen (http://en.wikipedia.org/wiki/Nitrogen) (Wiki)
Atmosphere of Earth (http://en.wikipedia.org/wiki/Atmosphere_of_Earth) (Wiki)

Jens
2010-Jan-18, 09:45 AM
Co2 might be problem. But I do not see how nitrogen is going to be a problem. As on Earth it accounts for 78% of the atmosphere.


At what density?

jonfr
2010-Jan-18, 10:46 AM
The goal would also be to get the pressure down to earth levels. Otherwise the terraforming effort is for nothing.

Van Rijn
2010-Jan-18, 12:03 PM
Van Rijn, This is fact not irrelevant. As it is smart to figure out what natural forces where doing here on Earth in forming the atmosphere. Your claim on the Co2 on early Earth and Venus today is unfounded in my opinion.


I have seen nothing that suggests the Earth had a massive CO2 atmosphere. If you can find something on that, present it. The articles you presented did not suggest a massive atmosphere on Earth - they just said that the atmosphere would have had a greater percentage of CO2.




Co2 might be problem.


For terraforming Venus, it is a problem. No ifs, ands, or buts.



But I do not see how nitrogen is going to be a problem. As on Earth it accounts for 78% of the atmosphere.


Because there is more nitrogen in the Venusian atmosphere than the Earth has. A nitrogen only Venusian atmosphere would still be substantially thicker than ours. That wouldn't be good.




The energy issue is not a issue at first look, as we get plenty from the sun it self on Venus.


That depends on how long you want to wait. In a previous post from that other thread, I quoted Oberg's calculation about what would be needed to remove most of the Venusian atmosphere within a century. Here's the quote:

"If we wish to remove 98% of the mass of the Venusian atmosphere in a reasonable time, say, 100 years, we must haul up a mass 10 quintillion tons, or 300,000 tons per second. Compare that to the flow along the Amazon river . . . 10,000 tons per second. The largest machines built which handle flowing water . . . handle 400 tons per second.

Or look at it from an energy requirement: hauling the mass of gas 100 km high, and then accelerating it by 20 km per second requires about 1025 ergs over a 100-year period. That's all the sunlight falling over the same period on an area of 10,000 square km assuming 100% efficiency . . .Throw in a factor of 10 for engineering reality, and the air scoopers must have an area of . . . three times the total area of Venus."

Note that he's talking about solar collector hardware that has a greater area than Venus itself.

jonfr
2010-Jan-18, 12:19 PM
Here is a research based on isotopic evidence on Earth early history. However, I do not know about the pressure on the early Earth. Since I do think that is a question that nobody can answer.

The evolution of the Earth's atmosphere is marked by a transition from an early atmosphere with very low oxygen content to one with an oxygen content within a few per cent of the present atmospheric level. Placing time constraints on this transition is of interest because it identifies the time when oxidative weathering became efficient, when ocean chemistry was transformed by delivery of oxygen and sulphate, and when a large part of Earth's ecology changed from anaerobic to aerobic1. The observation of non-mass-dependent sulphur isotope ratios in sedimentary rocks more than approx2.45 billion years (2.45 Gyr) old and the disappearance of this signal in younger sediments is taken as one of the strongest lines of evidence for the transition from an anoxic to an oxic atmosphere around 2.45 Gyr ago1, 2, 3, 4, 5.

Data source: Isotopic evidence for Mesoarchaean anoxia and changing atmospheric sulphur chemistry (http://www.nature.com/nature/journal/v449/n7163/abs/nature06202.html)

The Co2 is only a problem because how warm it is, around 460C.

The best and the most efficient way to "remove" atmosphere is to bind it into the ground. That should happen on it's own if a water catalysis can be introduced. But that in it self is a big problem. The other way to remove Co2 is by plants and bind it in carbon. But that has it's own problems, as requirement for water.

neilzero
2010-Jan-18, 03:37 PM
Hi EDG: Did you miss the 31 degrees c ? = naked body temperatures = ideal for growing plants. The liquid carbon dioxide ocean may be useful or not. We can keep it until we find a use. Humans can swim in it, as it has higher density than water? Fogg did not state the pressure = 20 atmospheres, perhaps, 1% oxygen(after many centuries of photosynthesis) 14% nitrogen/ 80% carbon dioxide = likely an improvement over 90 atmospheres. The plants still need water, fertilizer, and the sunshade needs to be transparent to the wave lengths most useful for photosynthesis, but perfection will come later, maybe. Neil

cjameshuff
2010-Jan-18, 05:00 PM
Your objections are not well founded in my opinion. Well founded objections have facts behind them, something to show that this cannot be done without a doubt. You have not shown any of that. I have pointed out what is already known, as that is the basic for this idea of mine.

If you think an objection is well founded, show why. Despite several chances, you made no attempt to do so, and so I will assume you rejected my points because they disagreed with your preconceptions, and have no actual answers. My objections do have facts behind them. I do not need to show that it can not be done beyond any doubt, only that certain things are more complex and more difficult than you believe. In some cases, you are dramatically underestimating the severity of a problem and the difficulty of dealing with it. You do not even know what parts of the the overall task are hard, and so you propose absurdities like a high-pressure, high-oxygen atmosphere that in reality would be rapidly lethal.



On the atmosphere on Earth, it is worth pointing out that the amount of atmosphere on Earth has not changed a lot of 4.6 billion years it has existed. There are at least no data that show otherwise.

As with the Martian water...what's your point? Earth's atmosphere has been relatively constant pressure, therefore it's easy to reduce the atmospheric pressure on Venus? The former not only does not imply the latter, it is evidence that the latter is false.



Unlike what you claim to know about what I know, and do not know. You are ignoring the obvious, you have no idea how long I have actually spend on this idea of terraforming Venus.

I'm going by evidence: your posts here. Your persistent tunnel vision in looking at atmospheric compositions while ignoring the absolute quantity of those atmospheres, something that you're still ignoring. Your lack of understanding of the rotation of Venus, and your attempt to use Earth as a model to prove that the day/night temperature swings would not be problematic.



The rotation of Venus is more complex that one might think. First of, it is not only longer as you have pointed out. But it is also counter-clockwise.

This is why I specifically said the solar day, not the 243 Earth day long sidereal day. I am well aware of the rotational characteristics of Venus. You, apparently, are not.



Jens, this is a case of spelling check failure. I will fix the error. Thanks. I am always looking for a criticism. However, I want that criticism to be build on something useful and proven, or something that has been disproven. But this a long project. One topic on a internet forum is not going to change its path in the long run.

The rotation period of Venus, the enormous quantity of atmosphere, the toxicity and danger of high pressure oxygen, etc are all proven facts. My other points...lack of water, practicality of better approaches to colonization, etc...are also based on facts. Your dismissal of them appears to be based on nothing but your desire for them to not be true. You're welcome to prove me wrong.

jonfr
2010-Jan-18, 05:44 PM
cjameshuff, it is not my job to prove your point. I have already linked to the science articles that I know of about this subject. I have also pointed out, in do right that many things are unknowns due to lack of research on Venus. Why can't you point me to a scientific article to support your claim. I do that, so can you. As it is quite strange demand on your part, that I should just believe everything that you claim here as the truth. While you don't support your claims with anything useful. If your points have facts behind them, link to them. Show me the data that you base your claim on!

I am yet to see a study that indicates that atmosphere pressure is the same over a planet live time. Thinking that might be the case is a big assumption that is not proven or disproved far as I know.

I'm going by evidence: your posts here. Your persistent tunnel vision in looking at atmospheric compositions while ignoring the absolute quantity of those atmospheres, something that you're still ignoring. Your lack of understanding of the rotation of Venus, and your attempt to use Earth as a model to prove that the day/night temperature swings would not be problematic.

In most likely is not going to be a problem. As weather system are going to distribute the heat (like they do on Earth). However, the question remains if the planet is going to have a lot of storm systems or not. That however might be the case if the difference is high. I am well advised on the rotation of Venus. Claim that to be a major problem is doubtful, as it does not have any basic evidence to it. But I must point, there is no research into that type of subject at this point. So the answer is at best nothing more then a guess.

ASPERA finally established the composition of the escaping plasma and measured that the escape of hydrogen to oxygen is, indeed, in the same ratio as water: two hydrogens for every oxygen.

Data source: Caught in the wind from the Sun (http://www.esa.int/esaMI/Venus_Express/SEM0G373R8F_0.html) and Sun strips away Venus's water (http://www.swissinfo.ch/eng/index/Sun_strips_away_Venuss_water.html?cid=984556)

The rotation period of Venus, the enormous quantity of atmosphere, the toxicity and danger of high pressure oxygen, etc are all proven facts. My other points...lack of water, practicality of better approaches to colonization, etc...are also based on facts. Your dismissal of them appears to be based on nothing but your desire for them to not be true. You're welcome to prove me wrong.

You are ignoring the process of terraforming, that is going to solve those issues along the lines. But I must point that on Earth there is a huge amount of Co2 bound in the earth, both in rock and in organic material, trees and lifeforms. The Co2 is bound there in the form of carbon due to activity of plants.

I support my case with the best scientific data that I can find. There are going to be gaps, because something has not be studied or simply is not known. I do not have every answer and I am not going to claim that I have them.

EDG
2010-Jan-18, 11:42 PM
I have already linked to the science articles that I know of about this subject.

Actually you've pointed to wiki entries and press releases. Have you read any actual science papers on the subject?

Van Rijn
2010-Jan-18, 11:47 PM
The Co2 is only a problem because how warm it is, around 460C.


No, it's also because there is so much of it. cjameshuff has also pointed this out, and this is a well accepted issue among would-be terraformers (read the references I mentioned).



The best and the most efficient way to "remove" atmosphere is to bind it into the ground. That should happen on it's own if a water catalysis can be introduced. But that in it self is a big problem


From the evidence, Venus once had a lot of water. Notably, the CO2 is not bound into the ground.



The other way to remove Co2 is by plants and bind it in carbon. But that has it's own problems, as requirement for water.

No. That CANNOT work. Assuming plants could be made to grow in the Venusian atmosphere, and assuming they could operate at high efficiency (not taking millions of years, as would be expected from reasonable production rates), they would ultimately increase the oxygen level too high, and the plants would burn back into CO2.

Again, this has ALL BEEN COVERED before. Read the thread I linked to. Read the books I noted. Before you make more incorrect statements, study the subject.

neilzero
2010-Jan-19, 12:48 AM
Hi Van Rijn: When we imply there are only two choices, we are usually wrong. Some times the 3d and 4th choice haven't been thought of or they are significantly less attractive than the other alternatives. In my polar plateau plan, I only sequester about 0.3% of the carbon, but I do sequester the sulphuric acid. Next to nothing is shipped out
In my version of the Fogg plan we sort of sequester most of the carbon dioxide in the ocean of liquid carbon dioxide, but ignore the sulphuric acid (possibly a big error).
I don't think any of the syphon plans are good physics. The make limestone plan is sequestering. The acid eating bacteria idea needs details: If the bacteria poop sodium sulfate, where do they get the sodium? Pooping HS = hydrogen sulfide or SO2 = sulpher dioxide, would only be a small improvement over H2SO4 = sulfuric acid. I'm also disappointed that jonfr does not yet have a plan, but let's cut him some slack; He may soon come up with a great idea/plan. Neil

EDG
2010-Jan-19, 12:53 AM
Is there actually that much H2SO4 in Venus' atmosphere anyway? I thought it was just in one layer in it? (and out of curiosity, where did the H2SO4 come from in the first place)?

jonfr
2010-Jan-19, 10:04 AM
EDG_, I have read what I can. But in many cases there are simply no studies to read up on. I have not just pointed to wiki articles. But I have also pointed out to science articles. But many of them I cannot read, because I have to pay for them. I am however going to check out what is on arXiv.org (http://arxiv.org/) web page.

Here is the reason for H2SO4 in the atmosphere in Venus.

Venus

Sulfuric acid is produced in the upper atmosphere of Venus by the Sun's photochemical action on carbon dioxide, sulfur dioxide, and water vapor. Ultraviolet photons of wavelengths less than 169 nm can photodissociate carbon dioxide into carbon monoxide and atomic oxygen.

Atomic oxygen is highly reactive. When it reacts with sulfur dioxide, a trace component of the Venusian atmosphere, the result is sulfur trioxide, which can combine with water vapor, another trace component of Venus's atmosphere, to yield sulfuric acid.

In the upper, cooler portions of Venus's atmosphere, sulfuric acid exists as a liquid, and thick sulfuric acid clouds completely obscure the planet's surface when viewed from above. The main cloud layer extends from 45–70 km above the planet's surface, with thinner hazes extending as low as 30 and as high as 90 km above the surface.

The permanent Venusian clouds produce a concentrated acid rain, as the clouds in the atmosphere of Earth produce water rain.

The atmosphere exhibits a sulfuric acid cycle. As sulfuric acid rain droplets fall down through the hotter layers of the atmosphere's temperature gradient, they are heated up and release water vapor, becoming more and more concentrated. When they reach temperatures above 300°C, sulfuric acid begins to decompose into sulfur trioxide and water, both in the gas phase. Sulfur trioxide is highly reactive and dissociates into sulfur dioxide and atomic oxygen, which oxidizes traces of carbon monoxide to form carbon dioxide.

Sulfur dioxide and water vapor rise on convection currents from the mid-level atmospheric layers to higher altitudes, where they will be transformed again into sulfuric acid, and the cycle repeats.

Data source: Sulfuric acid (http://en.wikipedia.org/wiki/Sulfuric_acid) (Wiki)

Van Rijn, there is so much Co2 because it has not been bound to the soil like here on Earth. From what I can read up on, it appears that Venus has a lot of water today. It just isn't solid or bound into some other chemicals on Venus.

Your opinion of how to remove Co2 from Venus atmosphere is disappointing. But it is not surprising at all. Oxygen levels can only go so high in the natural environment, far as I know (but I must point out that nobody knows why oxygen levels on Earth did go to 40% at one time, far as I know). But nothing has been proven, or disproved in regards to Venus.

Now, in regards to this tread. I am seeing that many here are bent on disproving anything that changes there view of the world. Even if that thing is just an idea. However, I find this type of attitude quite unacceptable for my part. As this type of view is does not allow progress to happen, it in fact blocks it.

This is going to be last answer for me in regards to general things about Venus. If someone has direct question in regards to this idea of mine. I will answer it best as I can.

Now it is back to lurking for me.

Lost Horizons
2010-Jan-19, 10:46 AM
The part of earth I came from could stand to be terraformed.

Van Rijn
2010-Jan-19, 11:07 AM
Van Rijn, there is so much Co2 because it has not been bound to the soil like here on Earth.


Yes, because Venus went through a very different process than Earth.


From what I can read up on, it appears that Venus has a lot of water today. It just isn't solid or bound into some other chemicals on Venus.


References? And, what do you mean by "a lot of water"? Relative to Earth or Mars, Venus has very little water.



Your opinion of how to remove Co2 from Venus atmosphere is disappointing. But it is not surprising at all.


My point wasn't about the specific method of removing CO2 from the Venusian atmosphere, but simply that physics dictates that ANY method that could operate in a reasonable time (no more than, say, a few thousand years) would necessarily require huge inputs of mass and/or energy.

I'm sure that is disappointing if you were hoping for some easy fix, but that's reality.



Now, in regards to this tread. I am seeing that many here are bent on disproving anything that changes there view of the world.


People here, who have studied this subject more than you, have been correcting some of your mistakes. But you've also been given references to useful material to read, which would clear up a lot of your mistaken notions.

jonfr
2010-Jan-19, 11:19 AM
Van Rijn,

References? And, what do you mean by "a lot of water." Relative to Earth or Mars, Venus has very little water.

The water on Venus is bound to various minerals (due to UV radiation), and possible rocks. But that has not been studied in detail at this point in time. You can see first post for references on the water.

Reality is often disappointing. And, it shouldn't be surprising.

Your views are disappointing because you are ignoring what nature has been doing for billions of years now.

People here, who have studied this subject more than you, have been correcting some of your mistakes. But you've also been given references to useful material to read, which would clear up a lot of your mistaken notions.

Then why don't they give me there own sources ? (When they put there claims forward) It should not be hard for them, if this is correct what you claim here. I need those sources so I can read up on them and compare with new studies and such. You can be sure that I will not just take your word for it, just because you say (claim) it doesn't mean it is true.

Van Rijn
2010-Jan-19, 11:37 AM
Van Rijn,

References? And, what do you mean by "a lot of water." Relative to Earth or Mars, Venus has very little water.

The water on Venus is bound to various minerals (due to UV radiation), and possible rocks. But that has not been studied in detail at this point in time. You can see first post for references on the water.


I don't see anything there suggesting a major find of water.

Everything I've ever seen on Venus indicates that it has trace amounts of water only.



Reality is often disappointing. And, it shouldn't be surprising.

Your views are disappointing because you are ignoring what nature has been doing for billions of years now.


What do you think I'm ignoring? You haven't presented a process that would be useful in terraforming.

By the way, one suggested terraforming proposal was to refine calcium and magnesium on Mercury, then bombard Venus with it, and let the CO2 bind with that. The problem is that it requires most of the surface of Mercury to be mined to a depth measured in miles.



Then why don't they give me there own sources ?


I gave you references to the terraforming books I use. I repeatedly suggested you start there before making more assertions.

As for things like the composition of the Venusian atmosphere, you can find references for that easily enough yourself.

jonfr
2010-Jan-19, 11:57 AM
Van Rijn,

You haven't presented a process that would be useful in terraforming.

How can I present something that I have not even invented yet. I dislike this type of fallacy like you show here.

I don't see anything there suggesting a major find of water.

Everything I've ever seen on Venus indicates that it has trace amounts of water only.

It turns out that you are wrong.

Water is a key molecule on Earth because it makes life possible. With Earth and Venus approximately the same size, and having formed at the same time, astronomers believe that both planets likely began with similar amounts of the precious liquid. Today, however, the proportions on each planet are extremely different. Earth’s atmosphere and oceans contain 100 000 times the total amount of water on Venus. In spite of the low concentration of water on Venus Delva and colleagues found that some 2x1024 hydrogen nuclei, a constituent atom of the water molecule, were being lost every second from Venus's day-side.

It also highlights a new mystery. “These results show that there could be at least twice as much hydrogen in the upper atmosphere of Venus than we thought,” says Delva. The detected hydrogen ions could exist in atmospheric regions high above the surface of the planet; but the source of these regions is unknown.

Data source: Where Did Venus's Water Go? (http://www.sciencedaily.com/releases/2008/12/081218094605.htm)

I gave you references to the terraforming books I use.

Are they any good is a question that should, and needs to be asked. I will check on those books in time. But first I need to do my pre-pre-research, before anything useful happens.

Here are some useful science articles.

Atmospheric and water loss from early Venus (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6T-4KNMB62-1&_user=713833&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1172043423&_rerunOrigin=scholar.google&_acct=C000039878&_version=1&_urlVersion=0&_userid=713833&md5=9ab2a759ad6d7adbbae7f9006e730086) (2006)

Implications of the high D/H ratio for the sources of water in Venus' atmosphere (http://www.nature.com/nature/journal/v363/n6428/abs/363428a0.html) (1993, Subscription)

GOURDHEAD
2010-Jan-19, 03:41 PM
If we think of the H2SO4 as a store house for water (that we can engineer microbes to release) and measure the thickness of the H2SO4 clouds, what is the partial pressure of the H2SO4 over the altitude range where the H2SO4 resides? If we can determine the partial presure of the H2SO4 over the 25 kilometer range of its greatest prevalence, we should be able to guess within 20% accuracy at the limits of the water available from the H2SO4. My guess is that there is enough to cover venus at an average depth of a few meters were Venus sufficiently cool at its surface.

Having designed microbes to dissipate the clouds thus initiating the catalytic action of steam and assuming that we start with 100 kg of microbes that double their mass and that of the digestive byproducts every 2 hours on average, we should have a large drink of water in ten years (pressure and temperature near the cloud tops being very close to those of Earth's surface). I'm not sure what the relative difference between the greenouse effects of H2SO4 versus steam are, but there may be some cooling of Venus from these changes.

Van Rijn
2010-Jan-19, 06:56 PM
I don't see anything there suggesting a major find of water.

Everything I've ever seen on Venus indicates that it has trace amounts of water only.

It turns out that you are wrong.


Really? The text you quoted supports my statement.

I'll highlight the important text:

Water is a key molecule on Earth because it makes life possible. With Earth and Venus approximately the same size, and having formed at the same time, astronomers believe that both planets likely began with similar amounts of the precious liquid. Today, however, the proportions on each planet are extremely different. Earth’s atmosphere and oceans contain 100 000 times the total amount of water on Venus.

cjameshuff
2010-Jan-19, 07:02 PM
If we think of the H2SO4 as a store house for water (that we can engineer microbes to release) and measure the thickness of the H2SO4 clouds, what is the partial pressure of the H2SO4 over the altitude range where the H2SO4 resides? If we can determine the partial presure of the H2SO4 over the 25 kilometer range of its greatest prevalence, we should be able to guess within 20% accuracy at the limits of the water available from the H2SO4. My guess is that there is enough to cover venus at an average depth of a few meters were Venus sufficiently cool at its surface.

The atmosphere of Venus contains 0.002% H2O...I assume this either includes that bound with sulfur oxides as sulfuric acid, or that the total quantity of sulfuric acid is actually negligible, as it isn't itself given a quantity in any description I've find of the atmospheric composition. ((0.00002*93 bar)/8.87 m/s^2)/(1000 kg/m^3) = 2 cm depth. (Ignoring the falloff of gravity with altitude...most of the mass of the atmosphere is close to the surface and essentially under full surface gravity.) And of course, the atmosphere would be bone dry at this point, and water would rapidly evaporate.

The sulfuric acid could be combined with oxides of calcium, sodium, magnesium, etc to form a sulfate salts and water, but much of the water will be trapped with the sulfates...calcium sulfate forms a hydrate with 2 water molecules per CaSO4 molecule, which is more than reaction of H2SO4 with CaO will provide. You can bake the water out with heat (this is why there's essentially no water left to be squeezed from the rocks on Venus' surface, contrary to jonfr's claims, something that any amount of research into hydrates would show), but then you face the problem of sequestering all those anhydrous salts and keeping them from coming in contact with water. Anhydrous calcium sulfate hydrates readily...this is why plaster of Paris hardens when mixed with water. Numerous other minerals form hydrates, you can expect the surface of Venus to absorb a considerable amount of water and lock it away in crystal lattices when the surface cools enough. Some CO2 can be sequestered this way too, the issue that jonfr persistently ignores is the sheer quantity of it. There's enough for a global layer of dry ice 650 meters deep, or a layer of calcite 850 meters deep, should you dig up enough calcium oxide to produce it. You can make magnesium carbonate, too, but that hydrates more readily, and can bind up to 5 water molecules per MgCO3 molecule.

The presence of sulfuric acid is only a bad thing for terraforming, though. It's not overly difficult to work with or protect against, and it's an extremely important industrial compound (its production being one of the major metrics of industrial development of a country). It's a natural resource, not a nuisance to be buried!

jonfr: you've given many links and quotes, but you've done little to tie them to your conclusions, only asserting that they support your ideas. Most of the issues I pointed out are simple facts that could be verified by any moderately detailed source of information on Venus. In fact, my arguments are better supported by your references than your own claims...you've shown little understanding of the sources you cite. Some of your claims aren't even poor understanding, but are just blatant wishful thinking: the idea that weather patterns would keep temperatures moderate over a 2 month long night and 2 month long day, for example. You even point to Earth as supposed support for your claim, ignoring the local seasonal variations experienced by much of the planet due to minor changes in incident sunlight.

As for it being a "fallacy" to ask you how solve the various problems involved in terraforming Venus which appear extremely difficult or impractical...you are claiming it is possible, and even easy to solve these problems. The natural expectation is that you know how they might be solved. If you do not, you have no grounds for dismissing them as you have been doing!

I've pointed out a number of very specific flaws with your goal, and can support all of them. If you would point to any specific claim that you doubt the validity of, I could address it in more detail, but all you've done is handwave, dismiss my points as ranting, and complain about me not strewing links around. It seems clear that you're not interested in anything that doesn't agree with your own view of reality and would rather just pretend those problems don't exist...you should be aware that this is not an approach likely to encourage collaboration.

jonfr
2010-Jan-19, 07:07 PM
Van Rijn, you sad trace amount. This is a lot more then a trace amount. I also must point out the fact we know little about geology on Venus, how and what type the soil is and how much water it contains. As water can be contained inside magma as it is here on Earth.

jonfr
2010-Jan-19, 07:15 PM
cjameshuff, Your claim about what I am saying is nonsense. It is also fact that you ignore repeately what I have stated all over this treated. That I do not have all the answers and I do not have all the solutions and there more research is needed to be done into this before anything useful happens. Hence, the 30 to 50 year time period that I estimate on this thing.

I do not have any wishful thinking. But I am not dismissing anything on the ground like you do. I simply do not dismiss any option because our current level of technology, knowledge and understanding is limited today on Venus, or anything else in this universe.

The problems are there to be solved, not to be dismissed like you handle them.

Van Rijn
2010-Jan-19, 07:19 PM
Van Rijn,

You haven't presented a process that would be useful in terraforming.

How can I present something that I have not even invented yet. I dislike this type of fallacy like you show here.


You didn't quote my full statement, which started with a question about a claim you had made. It was:


What do you think I'm ignoring? You haven't presented a process that would be useful in terraforming.

So, given your statement, perhaps I should respond with, "How can I ignore something you haven't even presented yet? I dislike this type of fallacy like you show here." :)

Look, this is supposed to be the Q&A section, but this seems to be more of a debate. You started this thread, but you don't seem to be so much asking questions as making statements. Do you have some space and astronomy questions to ask?

forrest noble
2010-Jan-19, 07:42 PM
jonfr,


Terraforming Venus project

I go along with those who assert that we are talking about millennia of time involved.

There have been those very daring individuals (who I agree with) that have proposed that we should get the terraforming going in this century by bio-engineering microbes that would float in the Venusian atmosphere and gobble up the CO2 (which in my opinion the technology is available now). Once this process gets started the rate of it could be evaluated and maybe more efficient microbes developed over time. The result could be a haze of microbes that upon their demise and sinking to the surface, could become "soil" for future underground farming, bio-fuel etc. long before the surface is habitable. It would take a comparatively small investment to get this process started. The rest of the terraforming could be resolved over the centuries -- such as initiating planet spin, providing a sun block, dumping in vast quantities of water from the asteroid belt and beyond, etc.

Another interesting proposal involved energy production for the Earth. The idea is that through satellites, solar energy through photo cells could be collected in Venusian orbit and the resultant energy micro-waved (or in another form of energy transported) to the Earth. If this technology, or something similar, ever became economically viable, that would be a big advance, I think, toward the eventual terraforming of Venus

jonfr
2010-Jan-19, 07:43 PM
Van Rijn, It was not necessary to quote your full statement, as the first part was in fact a question.

Look, this is supposed to be the Q&A section, but this seems to be more of a debate.

I was asking for help, and looking for information. I must point out, to those how say that this is impossible that it is a fact that a travelling to space was once impossible, and it was argued that it would never be achieved. Same goes for many other things in your lives today.

Space exploration has a long history (http://www.history.com/content/space/history), it is worth keeping that in mind before you dismiss something as impossible.

jonfr
2010-Jan-19, 07:48 PM
forrest noble, biological part of terraforming is necessary. But it is in fact too slow in the long run to be usable for a less then 20 years of terraforming a planet.

What other solution might be workable are a good question. But my best guess is that they must be in the nature of chemical one. What ever that might involve.

Van Rijn
2010-Jan-19, 07:58 PM
Van Rijn, It was not necessary to quote your full statement, as the first part was in fact a question.


I disagree, but I'm not debating this anymore.



I was asking for help, and looking for information.


And you got it.


I must point out, to those how say that this is impossible


The message was not that it is necessarily physically impossible, but that it would require extraordinary mass and/or energy transfers, likely permanent artificial maintenance, and certainly is well beyond current technology and practical capability.

cjameshuff
2010-Jan-19, 08:28 PM
cjameshuff, Your claim about what I am saying is nonsense. It is also fact that you ignore repeately what I have stated all over this treated. That I do not have all the answers and I do not have all the solutions and there more research is needed to be done into this before anything useful happens. Hence, the 30 to 50 year time period that I estimate on this thing.

I'm not ignoring anything you've said, or requiring you to have all the answers. You made specific claims about the atmosphere and rotation not being a problem, about Venus being easier to terraform than Mars, and so on. When issues were brought up, you said they weren't problems at all, or were not as hard to solve as they appeared. You're mostly being asked for answers for things you claimed to have answers for.

You are essentially now saying that you don't actually have anything to support any of your claims, and that it is unfair to expect you to. This is blatantly false, if you take a position, it is entirely reasonable to expect you to be able to support it.



I was asking for help, and looking for information. I must point out, to those how say that this is impossible that it is a fact that a travelling to space was once impossible, and it was argued that it would never be achieved. Same goes for many other things in your lives today.

A straw man. Nobody's said it was impossible. The problems raised have to do with specific things being far more difficult than you seem to understand, with misunderstandings of the problems faced, with flaws in your suggested approaches, and with certain assumptions on your part being inaccurate.

No matter how far technology advances, it will have to deal with the issues brought up in this thread. If you were really interested in terraforming Venus, you would be seeking information on the problems that would be encountered, so you would at least have an idea what sorts of solutions would be necessary. You instead took people raising issues and asking questions...doing just what you asked for in your initial post...as a personal attack, and are now handwaving the issues away as being solved by unspecified future technologies. One thing is certain...if Venus is ever terraformed, it won't be by taking the approach you've taken in this thread.

jonfr
2010-Jan-19, 08:51 PM
cjameshuff, Don't try to quote me on fallacies. Because I am well advised in them, this was no straw man (http://www.iep.utm.edu/fallacy/#Straw%20Man) at all. You however, have been begging the question (http://www.iep.utm.edu/fallacy/#Begging%20the%20Question) a lot. I have ignored it in order to trying to keep this tread on some sensible level. But also because this tread is not about fallacies.

I never claimed to have any answers, your are putting your word in my mouth by claiming anything like that. I sad this, to be exact.

The energy issue is not a issue at first look, as we get plenty from the sun it self on Venus. The speeding up the process is going to be a problem that needs to be solved.

You ignore the "what" and "if" that I put forward in my answers.

You say that you can support your claims and now it is time for you to support them.

neilzero
2010-Jan-20, 01:14 AM
Hi Forest: Let's call the microbe method, the Noble method. Variations of it are part of most plans to terraform Venus, and I agree, we can start very soon. Evaluate is the hard part as the microbes will scatter quickly and the results a few weeks later may be undetectable unless the first effort is massive, which it can't be with present lift capacity from Earth's surface. My guess is most of the microbes won't find enough water in the upper atmosphere of Venus to multiply, and other trace elements are likely also too scarce. The bottom line is we need to deliver water and nutrients as well as carbon dioxide eating microbes.
A long ago Analog article said that; if the algae = microbes could use 100% of the solar energy falling on Venus to convert carbon dioxide to oxygen and free carbon; the carbon dioxide would be down to about 0.04% in 600 years. Even 1% is optimistic near term, so 60,000 years. As you inferred, we can likely do better than 1% later in the Noble program.
Since the upper atmosphere spirals toward the poles, then descends, The algae or microbes becomes charcoal before they reach the surface near the poles. If the polar regions are cool enough we get humus instead of charcoal. Either way it is very fine dust that will scatter back toward the Equator unless we instal the dust fences I suggested 17 posts ago. The first 1000 years there will be too little oxygen to ignite the charcoal nor the dry humus. The analog article proposed scattering iron dust on the mounds of charcoal and humus to absorb even trace amounts of oxygen thus protecting the mounds from fire, in the second and subsequent 1000 year periods. My plateau plan (17 posts ago) buried the charcoal humus and sulfuric acid in the polar plateaus. Neil

forrest noble
2010-Jan-20, 04:17 AM
neilzero,

Neal,

I realize your plan is a lot more thought out than mine. The problem, the way I see it, is that we don't have the financing for anything complicated at the present time unless someone can also come up with a near-term commercial value to the effort.

As far as not having enough water, there is an area (height in the atmosphere of Venus) where water exists. It is polluted with sulfur and other particles but some microbes seemingly could tolerate this and would need something as food other than water anyway. The specific gravity of the microbes would have to be pretty exact so the microbes, while alive, would generally float at this altitude. Some water microbes on Earth genetically engineered could probably fit the bill. Larger microbial animals such a water bears might be bio-engineered with chlorophyll in the future to make the process happen at a quicker rate. Too high in the atmosphere is too volatile, heavy winds and temperature fluxes, too low and it becomes too hot. There are others problems such as daytime and night time which are extended periods, etc.

As you said, these chlorophyll bearing microbes could soon spread out so we would need a monitoring system. We could first send a neutral buoyancy "balloon" into the upper atmosphere with our critters as the package. The container would be open to the atmosphere and would monitor the progress of our critters. If the proliferation of the microbes was successful it could release them into the atmosphere as the container fills. Every lets say 20 years a newly "improved" version of the microbes could be sent up after testing here on Earth, and its progress evaluated. In time we could send up a number of these balloon packages.

I believe the key to any terraforming venture at any point in time (Mars or Venus), could not go beyond the finances available which would probably not be beyond this kind of relatively small experimental work. Better plans like your own, I think, will have to wait for the more distant future. In my opinion all space related ventures should have an economic value such as a Venus satellite solar power generating system. Without any relatively short-term financial benefit to an investor, country or otherwise, funding will always be extremely slow and not seemingly worth the mental effort until the funding is available.

violentquaker
2010-Jan-20, 04:54 AM
I have seen nothing that suggests the Earth had a massive CO2 atmosphere. If you can find something on that, present it. The articles you presented did not suggest a massive atmosphere on Earth - they just said that the atmosphere would have had a greater percentage of CO2.

For terraforming Venus, it is a problem. No ifs, ands, or buts.

Because there is more nitrogen in the Venusian atmosphere than the Earth has. A nitrogen only Venusian atmosphere would still be substantially thicker than ours. That wouldn't be good.

That depends on how long you want to wait. In a previous post from that other thread, I quoted Oberg's calculation about what would be needed to remove most of the Venusian atmosphere within a century. Here's the quote:

"If we wish to remove 98% of the mass of the Venusian atmosphere in a reasonable time, say, 100 years, we must haul up a mass 10 quintillion tons, or 300,000 tons per second. Compare that to the flow along the Amazon river . . . 10,000 tons per second. The largest machines built which handle flowing water . . . handle 400 tons per second.

Or look at it from an energy requirement: hauling the mass of gas 100 km high, and then accelerating it by 20 km per second requires about 1025 ergs over a 100-year period. That's all the sunlight falling over the same period on an area of 10,000 square km assuming 100% efficiency . . .Throw in a factor of 10 for engineering reality, and the air scoopers must have an area of . . . three times the total area of Venus."

Note that he's talking about solar collector hardware that has a greater area than Venus itself.

Just as a comparison of scale, 10 quintillion tons is about 5,000 times the total biomass on earth (http://energy.saving.nu/biomass/basics.shtml).

violentquaker
2010-Jan-20, 05:03 AM
Water is a key molecule on Earth because it makes life possible. With Earth and Venus approximately the same size, and having formed at the same time, astronomers believe that both planets likely began with similar amounts of the precious liquid. Today, however, the proportions on each planet are extremely different. Earth’s atmosphere and oceans contain 100 000 times the total amount of water on Venus. In spite of the low concentration of water on Venus Delva and colleagues found that some 2x1024 hydrogen nuclei, a constituent atom of the water molecule, were being lost every second from Venus's day-side.

So few grams of hydrogen per second are being lost from Venus's atmosphere. Interesting, but hydrogen is not water and that is not a lot of matter either.

cjameshuff
2010-Jan-20, 05:16 AM
jonfr: I'm not begging the question, and your comments about people saying it's impossible are a textbook example of a straw man argument. But I'm done, I will not discuss it further with you.

(Simply because I do not believe jonfr will discuss it in good faith. If someone else honestly has a question about something I've said, or wishes to point out an error, I'll gladly discuss it with them.)

forrest noble, neilzero:
The cloud-seeding proposals all face the problem that all they do is produce reduced carbon and an oxygen atmosphere. If you manage to keep the carbon from combusting and don't lock all the available hydrogen up in incompletely-carbonized organic material, you end up with a hot, corrosive, high-pressure oxygen environment that's harsher in some ways than Venus is today. The high altitude atmosphere (where pressure is about a quarter that on Earth's surface, due to the higher oxygen concentration) would be somewhat habitable, but the oxygen atmosphere will make it harder to support habitats there...you will need hot air or hydrogen/helium balloons, as breathable air is no longer a lift gas. The atmosphere would probably be easier to colonize if the planet was left with a CO2 atmosphere, an O2 atmosphere would almost certainly make the surface harder to work on. There's also the danger that the planet could also rapidly revert to a high-CO2 environment if underground fires start in those carbon layers. (look up coal seam fires and how difficult they can be to put out, and consider coal seam fires in a 95% O2 environment at 70 atmospheres)

You can mine enough oxides to sequester the CO2, but that's measured in kilometers of rock over the entire planetary surface (my calculation earlier of 850 meters of calcite was based on pure CaO with 100% absorption of CO2 to produce CaCO3, you'll need to move much more real-world rock to do the job), and you still have to get rid of much of the nitrogen. Rather than mine specific minerals for CO2 capture (which may not exist in sizable concentrated deposits), it might be easier to just move enough rock to make ~50 km high plateaus with walls around their rims to contain a breathable atmosphere. Stick the plateaus at the poles with the interior in eternal shadow, and use a number of sun-synchronous polar statites to give a 24 hour day/night period. This definitely seems to be colonizing Venus the hard way, though. It practically requires colonization for completion...by the time the plateaus are habitable, Venus will probably have a worker population far too large for them to ever support, already self-sufficient and living in comfortable habitats. (and there's the question of how the crust will react to 50-km-high piles of rock being stuck at the poles)

Van Rijn
2010-Jan-20, 05:19 AM
There have been those very daring individuals (who I agree with) that have proposed that we should get the terraforming going in this century by bio-engineering microbes that would float in the Venusian atmosphere and gobble up the CO2 (which in my opinion the technology is available now).


This idea (and many problems with it, along with some variations on the concept) is discussed in substantial detail starting on page 346 of Fogg's Terraforming.

The biological terraforming idea was originally proposed by Carl Sagan in 1961. He made a very short proposal (almost a throwaway comment) of possibly splitting out oxygen from CO2 to improve habitability.

The idea assumed a far less hostile environment than we now know to exist. He was assuming about thirty (30) times less CO2, about a third of the nitrogen, that Venus had water clouds, and a substantially lower surface temperature. Obviously, it would be much easier to deal with this much thinner atmosphere, though it isn't clear that it would have worked even given those conditions. As it is, Sagan himself later said, in Pale Blue Dot, that given what we now know about Venus, it couldn't work.

If Venus is to be terraformed, most of the atmosphere must be removed. That can either be by ejecting it from the planet, or storing/sequestering it in some fashion. Biology isn't going to do that.

astromark
2010-Jan-20, 05:32 AM
Unfortunately Venus is not the best choice for our species to inhabit. Being very hostile and way to hot. I am pleased that funding has been introduced. Unless there is a clear and urgent need its just not ever going to happen. Even in the long term its a bad idea... As Sol expands and super heats the inner planets. We would not want to be closer... Look to the moons of the gas giants. One of those could be a little closer as a candidate. In case you have not noticed the funding of space programs and science general is found wanting... Sorry for the cold water pour but, Venus is just wrong for too many reasons.

cjameshuff
2010-Jan-20, 05:57 AM
By the way, one suggested terraforming proposal was to refine calcium and magnesium on Mercury, then bombard Venus with it, and let the CO2 bind with that. The problem is that it requires most of the surface of Mercury to be mined to a depth measured in miles.

Using aluminum and silicon instead might help. Both are more abundant in Earth's crust (and probably Mercury's) than calcium and magnesium, and both will bind more oxygen per unit of mass. Still an incredible amount of material to move, and it'll put any useful mineral deposits deep underground. It'll also cover the planet with a kilometers-deep layer of fine silica and alumina dust. Plus there's the question of why you're burning vast (as in planet-covering) quantities of aluminum rather than building with it. (And there's an idea...just roof the entire planet over. You'll be sending enough aluminum to do so anyway...)

forrest noble
2010-Jan-20, 06:25 AM
I agree there are some serious problems concerning terraforming Venus that we'll only see drawing-board answers to in our lifetime. More practical ideas might be orbital hotels such as those planned by Bigelow Aerospace for the Earth -- http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1153

-- or in time maybe orbital Venusian cities. In time the rich will want a different thrill and may get it in an extended stay in a orbital hotel around Venus. In time sunblocks for the Earth (global warming?) may lead to sunblocks for Venus.

On the wilder side some strategically placed H-bombs could blow some of the Venusian atmosphere into a slower inner solar orbit where it would slowly drift toward the sun, while causing a nuclear winter on Venus because of the vastly polluted atmosphere while maybe upping the planetary spin a hair; also in time possibly some outward moving material might beatify our night skies by increased meteorites. I'm sure there are lots of "great :)" ideas like this last one that would be very popular here on Earth :)

Van Rijn
2010-Jan-20, 06:42 AM
That's a good point, and an interesting question for me. Why is it that many people are keen about terraforming Mars or Venus, but not so much about the earth?


I remembered this post from earlier, and wanted to respond to this question with some of my ideas on this.

- I think the idea of new places to live is an important one. It isn't about giving up on Earth, but of growing beyond just Earth.

- While terraforming Earth is undoubtedly far easier than terraforming any other worlds in this system, the risk is also more obvious.

- It is a very common theme in science fiction, where it is usually presented attractively.

- It is (at least to me), a fascinating subject, which is why I've read about all the serious or semi-serious material I've been able to find on terraforming.

- Some of the most widely known ideas about terraforming Mars or Venus leave out very important details, or are just flat wrong, and make it look far easier (and therefore much more attractive) than it really is. That's somewhat self-perpetuating: "Easy" (but wrong) terraforming ideas sound good, so are more likely to be spread around. People don't want to hear about the problems (for examples of that, you need look no further than this thread).

IsaacKuo
2010-Jan-20, 03:27 PM
Also:

- Terraforming Earth is does not feel necessary, since it already supports life.

IsaacKuo
2010-Jan-20, 03:37 PM
More practical ideas might be orbital hotels such as those planned by Bigelow Aerospace for the Earth -- http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1153

-- or in time maybe orbital Venusian cities. In time the rich will want a different thrill and may get it in an extended stay in a orbital hotel around Venus.
Orbital space habitats make more sense than terraforming all around. Not just for some "hotels", but also for entire biospheres. You get far more living area for the buck, and it scales down well.

In time sunblocks for the Earth (global warming?) may lead to sunblocks for Venus.
A sunblock for Venus would be relatively easy. And also pointless.

Hop_David
2010-Jan-20, 07:38 PM
The issue is that there are basically two choices: Sequester the CO2 and nitrogen, or eject it from Venus. Unless you plan on breaking the laws of physics, either of those choices would require enormous inputs of mass and energy. You simply aren't going to get out of that.

In Kim Stanley Robinson's Mars trilogy, he terraforms Mars by dropping icey bodies from the Oort to Mars. I had some objections to this. It would take an icey body from the Oort a century or more to reach Mars. When it arrives, it'd be moving close to solar escape velocity (about 34 km/sec in Mars' neighborhood). Depending on what angle the body's orbit intersects Mars' orbit, it would impact Mars any where from 11 km/sec to 60 km/sec. I believe the impact would blast away more Martian atmosphere than the icey body would leave.

An Oort object would hit Venus with an even greater velocity: 17 km/sec to 80 km/sec. Like Mars, I believe the impact would blast away more atmosphere than the body would add.

So I regard Robinson's terraforming method more effective for Venus than Mars.

But dropping Oort objects for terraforming isn't very plausible.

IsaacKuo
2010-Jan-20, 08:44 PM
Depending on what angle the body's orbit intersects Mars' orbit, it would impact Mars any where from 11 km/sec to 60 km/sec. I believe the impact would blast away more Martian atmosphere than the icey body would leave.
I would doubt it. The escape velocity of Mars is 5km/s. If we assume an impact velocity of 15km/s, then that means the impactor could theoretically blast away eight times its own mass in Martian atmosphere. But would the energy of its impact really be absorbed by only eight times its own mass? I doubt it, at least for impactors big enough to reach the surface.

Hop_David
2010-Jan-21, 05:54 PM
I would doubt it. The escape velocity of Mars is 5km/s. If we assume an impact velocity of 15km/s, then that means the impactor could theoretically blast away eight times its own mass in Martian atmosphere. But would the energy of its impact really be absorbed by only eight times its own mass? I doubt it, at least for impactors big enough to reach the surface.

Your challenge is prompting me to Google . . .

Melosh and Vickery suggested that Mars lost much of it's atmosphere due to impacts causing atmospheric erosion.

"The model by Melosh and Vickery shows
that for a given planet, impact of projectiles
larger than a given mass can remove the
entire atmosphere above the tangent plane to
the planetary surface at the point of impact.
For Mars, they show the smallest impactor
to be ~4x10^13 kg, or ~3 km in diameter for a
silicate object; oblique impacts may reduce
the minimum mass by a factor of five."

www.lpi.usra.edu/meetings/lpsc97/pdf/1807.PDF

While giving 4x10^13 as a minimum mass, they don't mention velocity of the impactor. I'd like to learn more about their model, but my first efforts just give me abstracts and pay buttons if I want to view the full paper.

Hopefully their model will suggest minimum mass and velocity to erode Venus atmosphere. If the impactor is a metallic body or a body lacking volatiles, it wouldn't add to the atmosphere in any case.

I might search some more later.

neilzero
2010-Jan-22, 06:33 AM
Hi Isaac: I think I agree, we have much better uses for our space dollars in this century than analyzing the terraforming of Venus. Do you have an other reason for saying a sun block for Venus is relatively easy, but pointless. I thought the 31 c liquid carbon dioxide ocean by Fogg was somewhat viable. Neil

Van Rijn
2010-Jan-22, 07:08 AM
Hopefully their model will suggest minimum mass and velocity to erode Venus atmosphere. If the impactor is a metallic body or a body lacking volatiles, it wouldn't add to the atmosphere in any case.

I might search some more later.

Fogg discusses impact erosion on Venus on pages 366 and 367 of Terraforming. Because Venus has far more mass than Mars, it is also far less effective than for Mars. The short version is that it isn't feasible for Venus, but here's some of the background and numbers from the book:



When a collision occurs at less than about twice the planet's escape velocity or the impactor is less than a certain mass, then no more than a plug of gas is lost to space equivalent to the column mass traversed by the projectile. This is negligible compared to the mass of the atmosphere. More energetic impacts generate a vapor plume and shock wave that can exceed the gravitational binding energy of a large mass of atmosphere. However, the spherical geometry of a planet limits the portion of the atmosphere lost to space as being that gas above a plane tangent to the surface at ground zero. . . . tangent plane ejection on Venus needs roughly ~700 km diameter impactors hitting at >20 km/s . . . 3333 impacts large enough to cause cause tangent plane ejections still leave . . . ~35 bars.

So, more than three thousand impacts of 700 km diameter objects (larger than everything in the asteroid belt other than Ceres) still leaves a thick atmosphere.

IsaacKuo
2010-Jan-22, 02:47 PM
Do you have an other reason for saying a sun block for Venus is relatively easy, but pointless.
My thinking is that a sun shade can be done in a straightforward way with much less resources than the other things discussed in this thread, but that it would not accomplish anything useful.

It could reduce the temperature of Venus, but so what? It doesn't make Venus any more useful for colonization or anything else--space habitats, Earth's oceans, Mars, or even Ceres are still better options.

I thought the 31 c liquid carbon dioxide ocean by Fogg was somewhat viable. Neil
Viable for what? If you want floating Venus habitats, you'd do better by not terraforming Venus at all. Breathable air is a lifting gas, making cloud cities (http://www.universetoday.com/2008/07/16/colonizing-venus-with-floating-cities/) in Venus's current atmosphere a potentially viable option.

Murphy
2010-Jan-22, 08:27 PM
About a Sun shade for Venus, I'm not well informed about the details of this or how it might work, but couldn't there be a way to both get rid of the Venusian atmosphere and use it for space colonies?

I'm just brain storming here, so this may be complete rubbish, but I'm thinking, if you're using a massive sun shade to cool Venus why not put solar cells on the sun-facing side of the shade to collect all that energy? And then use that energy to get rid of the atmosphere.

If the solar shade was a disc the same size as Venus, then it would have an area of 115,066,184,211,608 square meters (or about 115 million square kms). Now, if the Solar Insolation at Venus is 2,613 W/m^2 (at least that's what the Internet tells me), and if the photovoltaic cells are, let's say... 50% efficient (a reasonable possibility for the future, although I've heard that they may be able to go up to 70%), then the shade would provide about 150,000 Terawatts! (1.5e+17 watts). That's an almost unimaginable amount of power, surely it can be put to good work in terraforming Venus.

So, the shade cools Venus down so that it's atmosphere begins to freeze into a solid on the surface, then we use the power provided by the shade to somehow get rid of the now frozen atmosphere. I'm not entirely sure how to do this, but maybe it could be beamed to the surface with microwaves and used to power Space elevators or mass drivers to shoot the frozen CO2, etc into orbit (via a Robotic infrastructure). This atmosphere could then be used for space colonise, think of it as essentially mining Venus with terraforming as a by product.

Then, (after however many centuries) the atmosphere has been fully mined away leaving only an Earth-like composition and pressure, the sun shade is removed (perhaps moved to another part of the solar system or broken down and recycled), and the colonization and terraforming process can begin. So we get a new terraformed planet and a whole load of material that can be used to build and sustain space colonies, so why need it be a choice between Venus terraforming and Space colonies, can't the two compliment each other?

Hop_David
2010-Jan-22, 08:31 PM
Fogg discusses impact erosion on Venus on pages 366 and 367 of Terraforming. Because Venus has far more mass than Mars, it is also far less effective than for Mars. The short version is that it isn't feasible for Venus, but here's some of the background and numbers from the book:



So, more than three thousand impacts of 700 km diameter objects (larger than everything in the asteroid belt other than Ceres) still leaves a thick atmosphere.

Venus velocity is 35 km/sec. An object from the outer system would be moving around 48 km/sec when near Venus.

So Vinf could range from 13 km/sec (if object's velocity vector is parallel with Venus' velocity vector) to 83 km/sec (if object's velocity vector is point the opposite direction than Venus' velocity vector).

Such an object crossing Venus' orbit at 60 degrees would impact Venus at 44 km/sec.

On 1 ton object moving at 20 km/sec would have the same kinetic energy as a 4 ton object moving 40 km/sec.

A 1 ton object moving at 20 km/sec would have the same kineticic energy as a 9 ton object moving 60 km/sec.

So it seems to me, depending on what angle the object intersects Venus' orbit, the object could be considerably smaller than 700 km diameter objects Fogg mentions.

Edit: corrected arithmetic error

cjameshuff
2010-Jan-22, 10:07 PM
So, more than three thousand impacts of 700 km diameter objects (larger than everything in the asteroid belt other than Ceres) still leaves a thick atmosphere.

An alternative approach...do the deep freeze, pile the frozen atmosphere up in mountains so a given impact can more efficiently blast it away, and rather than big impacts at relatively low ("merely" orbital) velocities, use smaller impactors thrown from sailcraft on fast solar flyby trajectories. The projectiles could be little more than a sail, guidance systems, and some equipment to haul the sail in before impact, the whole thing serving as the projectile...such a projectile might consistently manage impact velocities of over 100 km/s. I cringe at the quantities of solar sail material made and thrown away this way, but it might do the job without requiring more impactor mass than exists in our asteroid belt.

Cooling Venus to the point of forming CO2 oceans/glaciers might be of use other than as a terraforming stage. The oceans would be an effective heat sink for industry and nuclear power plants, at least. They would be useful for transportation as well...but so would airships on a hot Venus. Wind power on a hot Venus is an abundant and widely available resource that would be eliminated in the process of cooling Venus...nuclear power would be more effective and you could beam power down from orbit, but more complex, and the only clear advantage I see is the power density achievable. Perhaps cooling to a lesser degree would allow habitats to stay in denser regions of the atmosphere and carry more mass...

Hop_David
2010-Jan-22, 10:28 PM
An alternative approach...do the deep freeze, pile the frozen atmosphere up in mountains so a given impact can more efficiently blast it away,

I'm guessing it would take quite a long time for a Venus-Sun L1 sunshade to cool Venus to where the CO2 freezes


and rather than big impacts at relatively low ("merely" orbital) velocities, use smaller impactors thrown from sailcraft on fast solar flyby trajectories. The projectiles could be little more than a sail, guidance systems, and some equipment to haul the sail in before impact, the whole thing serving as the projectile...such a projectile might consistently manage impact velocities of over 100 km/s.

It takes a long time to achieve delta V with solar sails. If solar sails managed to accelerate the impactors to solar escape velocity (around 49 km/sec in Venus' neighborhood), they wouldn't hang around long and imparting additional velocity for a Venus impact wouldn't be possible.

I believe the maximum practical velocity would be a near solar escape velocity retrograde orbit impacting Venus at perihelion. The impact velocity would be in the neighborhood of 85 km/sec.

cjameshuff
2010-Jan-22, 11:46 PM
I'm guessing it would take quite a long time for a Venus-Sun L1 sunshade to cool Venus to where the CO2 freezes

No argument with the timescale, but I doubt they would be at Venus-Sol L1. An arrangement of statites might be able to make sunshades loiter in the right positions much closer to Venus (balancing on light reflected from night-side statites), or the shades could simply be in Venus orbit. I strongly suspect either approach would require much less actual sunshade area...



It takes a long time to achieve delta V with solar sails. If solar sails managed to accelerate the impactors to solar escape velocity (around 49 km/sec in Venus' neighborhood), they wouldn't hang around long and imparting additional velocity for a Venus impact wouldn't be possible.

This is a misconception, read up on the fast solar sailing trajectories I referred to. Such trajectories could send probes to Pluto and the Kuiper belt in just a few years, the vast majority of the velocity being gained in a matter of months after launch, most of that time being spent in the initial outward and backward part of the trajectory leading up to the solar flyby. The bulk of the acceleration is done during a flyby of the sun. The velocity achieved depends on the loading of the sail, and these impactors needn't carry any payload, as their entire purpose is to get their own mass to as high a velocity as possible. Sun-relative velocities in the range of 75-100 km/s are potentially achievable, and the trajectory can be retrograde, adding some of Venus' 35 km/s to the impact velocity.

See:
http://en.wikipedia.org/wiki/Solar_sail#H-reversal_sun_flyby_trajectory
http://interstellar.jpl.nasa.gov/interstellar/probe/requirements/concept.html
http://interstellar.jpl.nasa.gov/interstellar/ISP_Space2K_v4.pdf

Van Rijn
2010-Jan-23, 05:05 AM
I'm guessing it would take quite a long time for a Venus-Sun L1 sunshade to cool Venus to where the CO2 freezes


Fogg discusses that as well, though it's based on a Paul Birch article. A few years ago in another Terraforming thread, I ran through the numbers, based on the discussion in his book. Here it is again:


Martin J. Fogg goes into this in some detail in his book, "Terraforming." According to him, with a complete cutoff of sunlight, it would take a total of about 200 years in 5 stages. The first period, where the pressure would stay roughly stable but the temperature would drop from around 450 to 31C, would take 58 years. Then CO2 rain would begin to fall, forming oceans and the pressure would drop, but the temperature would be stable for 27 years. Then the temperature and pressure would fall for 97 years with the temperature dropping to -56C. Then the pressure (now down to 7 atmospheres) and the temperature would stay stable for 7 years, while the oceans freeze to dry ice. Finally, in another 9 years, the rest of the CO2 would freeze out, leaving mostly nitrogen, and the temperature would drop to -81C. The remaining atmosphere would still be substantially thicker than earth's. They don't take the last possible stage (dealing with the nitrogen).

Van Rijn
2010-Jan-23, 05:14 AM
An alternative approach...do the deep freeze, pile the frozen atmosphere up in mountains so a given impact can more efficiently blast it away, and rather than big impacts at relatively low ("merely" orbital) velocities, use smaller impactors thrown from sailcraft on fast solar flyby trajectories.


A couple of the ideas I've seen proposed are: (1) Roofing over the CO2 - that is, store it, and live on an artificial surface built above it. (2) Launch it into space with arrays of mass drivers. This would also be a long term project, since it would take a lot of mass drivers, and there would be limits to how much energy could be supplied to the mass drivers without warming things up again. At least frozen CO2 would be easier to collect for transportation.

Hop_David
2010-Jan-23, 08:40 PM
This is a misconception, read up on the fast solar sailing trajectories I referred to. Such trajectories could send probes to Pluto and the Kuiper belt in just a few years, the vast majority of the velocity being gained in a matter of months after launch, most of that time being spent in the initial outward and backward part of the trajectory leading up to the solar flyby. The bulk of the acceleration is done during a flyby of the sun. The velocity achieved depends on the loading of the sail, and these impactors needn't carry any payload, as their entire purpose is to get their own mass to as high a velocity as possible. Sun-relative velocities in the range of 75-100 km/s are potentially achievable, and the trajectory can be retrograde, adding some of Venus' 35 km/s to the impact velocity.

See:
http://en.wikipedia.org/wiki/Solar_sail#H-reversal_sun_flyby_trajectory
http://interstellar.jpl.nasa.gov/interstellar/probe/requirements/concept.html
http://interstellar.jpl.nasa.gov/interstellar/ISP_Space2K_v4.pdf

Well, I stand corrected.

Still don't like using them for Venus impactors though. Making a sail big enough to send a substantial mass to Venus would require a lot of time and effort.

Would a new sail have to be made for each impactor? If the sail doesn't crash into Venus, it seems like it'd sail out of the solar system on a hyperbolic path.

violentquaker
2010-Jan-23, 09:47 PM
Well, I stand corrected.

Still don't like using them for Venus impactors though. Making a sail big enough to send a substantial mass to Venus would require a lot of time and effort.

Would a new sail have to be made for each impactor? If the sail doesn't crash into Venus, it seems like it'd sail out of the solar system on a hyperbolic path.

Yes, it seems like it would be worthwhile to design these sails to miss Venus and decelerate below the sun's escape velocity so they could be reused.

cjameshuff
2010-Jan-23, 10:02 PM
Still don't like using them for Venus impactors though. Making a sail big enough to send a substantial mass to Venus would require a lot of time and effort.

Would a new sail have to be made for each impactor? If the sail doesn't crash into Venus, it seems like it'd sail out of the solar system on a hyperbolic path.

My suggestion was for suggested the sail to carry no payload whatsoever, consisting only of the sail and control equipment, minimizing sail loading and maximizing velocity. It would haul in the sail before impact, with the entire vehicle forming the impactor.

The point is not to send a substantial amount of mass to Venus, it is to minimize the mass used to blast frozen and piled up atmosphere off the surface, by maximizing impact velocity...the alternative approach had the minor issue of requiring many times the amount of matter in the asteroid belt. And yes, it'd take a lot of time and effort, but you're talking about removing 90-some times Earth's atmosphere from a gravity well nearly as deep. The unreasonable amount of work required to do this has been the major topic of this thread.

cjameshuff
2010-Jan-23, 10:06 PM
Yes, it seems like it would be worthwhile to design these sails to miss Venus and decelerate below the sun's escape velocity so they could be reused.

That's not an option, unless you use far lower impact velocities. The sails would be heading for interstellar space at up to ~20 AU/year, and there's nothing out there they can use to turn around.

violentquaker
2010-Jan-24, 01:25 AM
My suggestion was for suggested the sail to carry no payload whatsoever, consisting only of the sail and control equipment, minimizing sail loading and maximizing velocity. It would haul in the sail before impact, with the entire vehicle forming the impactor.

The point is not to send a substantial amount of mass to Venus, it is to minimize the mass used to blast frozen and piled up atmosphere off the surface, by maximizing impact velocity...the alternative approach had the minor issue of requiring many times the amount of matter in the asteroid belt. And yes, it'd take a lot of time and effort, but you're talking about removing 90-some times Earth's atmosphere from a gravity well nearly as deep. The unreasonable amount of work required to do this has been the major topic of this thread.

Fair enough. Next question though - how cold would you need to get Venus in order for the atmosphere to condense? Sure the CO2 would go pretty quickly, but you would still have the lighter gasses that might be enough to prevent the sails from reaching the surface.

Van Rijn
2010-Jan-24, 02:19 AM
Fair enough. Next question though - how cold would you need to get Venus in order for the atmosphere to condense? Sure the CO2 would go pretty quickly, but you would still have the lighter gasses that might be enough to prevent the sails from reaching the surface.

My post here (http://www.bautforum.com/1665938-post88.html) covered CO2. Nitrogen accounts for nearly all of the atmosphere other than CO2. It becomes a liquid at −196 C (−321 F), solid at −210 C (−346 F). It does seem to me to be extremely inefficient to first freeze it out, then attempt to blast it into space. Controlled launch would be far more efficient (though still a very difficult task).

violentquaker
2010-Jan-24, 04:29 AM
My post here (http://www.bautforum.com/1665938-post88.html) covered CO2. Nitrogen accounts for nearly all of the atmosphere other than CO2. It becomes a liquid at −196 C (−321 F), solid at −210 C (−346 F). It does seem to me to be extremely inefficient to first freeze it out, then attempt to blast it into space. Controlled launch would be far more efficient (though still a very difficult task).

Of course the phase change temperatures of Nitrogen will vary with pressure, but it's safe to say significantly colder than CO2. Methinks freezing the CO2, then getting rid of the Nitrogen through a different method, then the solar sail impacts to blast off the CO2 snow (though I too am unconvinced that mass drivers or another method wouldn't be more efficient)?

cjameshuff
2010-Jan-24, 04:58 AM
My post here (http://www.bautforum.com/1665938-post88.html) covered CO2. Nitrogen accounts for nearly all of the atmosphere other than CO2. It becomes a liquid at −196 C (−321 F), solid at −210 C (−346 F). It does seem to me to be extremely inefficient to first freeze it out, then attempt to blast it into space. Controlled launch would be far more efficient (though still a very difficult task).

In terms of energy and material resource usage, all it involves is making vast amounts of solar sail material. It's roundabout, but seems likely to be one of the more efficient approaches. "Controlled launch" will take comparable numbers of ground-to-orbit rocket vehicles or an enormous number of mass driver launches. Both of these will also have to deal with the atmosphere being in the way, unless you freeze it out for this approach too...freezing the atmosphere out seems to me to almost be a required first step.

It might be very inefficient at putting the impact energy to use at removing atmosphere, but that energy only cost you the time required for a trip around the sun to obtain. More direct approaches require more direct application of energy. Orbital boosters and their fuel have to be made, nuclear power generated or solar power collected and converted into electrical or thermal power suitable for running the machinery...

One other possibility that comes to mind is to use statites to heat and ionize portions of the upper atmosphere with focused sunlight, and orbiting satellites carrying superconducting magnets to tease up the ionized atmosphere so that it gets pulled away at a greater rate by the solar wind. I suspect this would be one of the most efficient and probably one of the slowest and most difficult techniques...

violentquaker
2010-Jan-24, 05:29 AM
In terms of energy and material resource usage, all it involves is making vast amounts of solar sail material. It's roundabout, but seems likely to be one of the more efficient approaches. "Controlled launch" will take comparable numbers of ground-to-orbit rocket vehicles or an enormous number of mass driver launches. Both of these will also have to deal with the atmosphere being in the way, unless you freeze it out for this approach too...freezing the atmosphere out seems to me to almost be a required first step.

It might be very inefficient at putting the impact energy to use at removing atmosphere, but that energy only cost you the time required for a trip around the sun to obtain. More direct approaches require more direct application of energy. Orbital boosters and their fuel have to be made, nuclear power generated or solar power collected and converted into electrical or thermal power suitable for running the machinery...

One other possibility that comes to mind is to use statites to heat and ionize portions of the upper atmosphere with focused sunlight, and orbiting satellites carrying superconducting magnets to tease up the ionized atmosphere so that it gets pulled away at a greater rate by the solar wind. I suspect this would be one of the most efficient and probably one of the slowest and most difficult techniques...

How about a concept similar to a space elevator: a space pipeline? Just pump the atmo up the pipe to the base station in venus-stationary orbit, where solar wind will blow it into interplanetary space?

Now, how high is venus-stationary orbit with its ~200 day long rotation?

Van Rijn
2010-Jan-24, 05:52 AM
How about a concept similar to a space elevator: a space pipeline? Just pump the atmo up the pipe to the base station in venus-stationary orbit, where solar wind will blow it into interplanetary space?


A pump and pipe won't work. It needs to be put in tanks, or something equivalent, then the tanks would have to be transported up the elevator and emptied. Of course, the tanks could be returned back down the elevator.

It's about what I had here (the quote from Oberg doesn't assume synchronous elevators, but the mass and energy numbers would be essentially the same):

http://www.bautforum.com/1662745-post38.html



Now, how high is venus-stationary orbit with its ~200 day long rotation?

I calculated that before. From memory, it's about a million miles out.

cjameshuff
2010-Jan-24, 05:54 AM
How about a concept similar to a space elevator: a space pipeline? Just pump the atmo up the pipe to the base station in venus-stationary orbit, where solar wind will blow it into interplanetary space?

Now, how high is venus-stationary orbit with its ~200 day long rotation?

T = 2*pi*sqrt(r^3/(G*m))
243 days = 2*pi*sqrt(r^3/(G*4.87e24 kg))
((243 days/(2*pi))^2*G*4.87e24 kg)^(1/3) = 1.5e6 km, about 5 light seconds, 4 times the distance to the moon, 0.01 AU, 1.4% of the distance to the sun.

A synchronous space elevator is theoretically marginally possible on Earth, it seems utterly impossible on Venus. One synchronous with the upper atmosphere is closer to achievable due to the high superrotation, but you're stripping atmosphere away...that's not going to work for long. Scooping a large portion of the atmosphere away with non-synchronous hypersonic skyhooks seems unlikely to be much more practical.

Van Rijn
2010-Jan-24, 06:06 AM
A synchronous space elevator is theoretically marginally possible on Earth, it seems utterly impossible on Venus.


A space fountain (http://en.wikipedia.org/wiki/Space_fountain) design is theoretically possible for Venus. I'm not saying I think it's likely, though.

IsaacKuo
2010-Jan-24, 10:51 AM
Back to the idea of solar sail impactors--since overall mass requirement is such an issue, I think perhaps reusable "air plows" would be better than impactors.

An air plow is essentially an upward tilted/curved slab or wedge that flies through the upper atmosphere. It has strong negative lift, but this is overwhelmed by the de facto orbital "upward" lift from having much greater than escape velocity.

As it flies through the upper atmosphere, it imparts escape velocity to the air above its path.

The air plow's basic flight plan is a retrograde solar orbit. It spends most its time recovering lost speed, with the occasional encounter with Venus. When it encounters Venus, it plows away a strip of atmosphere, slowing itself down in the process.

Hop_David
2010-Jan-24, 08:52 PM
My suggestion was for suggested the sail to carry no payload whatsoever, consisting only of the sail and control equipment, minimizing sail loading and maximizing velocity. It would haul in the sail before impact, with the entire vehicle forming the impactor.

The point is not to send a substantial amount of mass to Venus, it is to minimize the mass used to blast frozen and piled up atmosphere off the surface, by maximizing impact velocity...the alternative approach had the minor issue of requiring many times the amount of matter in the asteroid belt. And yes, it'd take a lot of time and effort, but you're talking about removing 90-some times Earth's atmosphere from a gravity well nearly as deep. The unreasonable amount of work required to do this has been the major topic of this thread.

Even if you achieve high velocities, you will still need a substantial mass.

How will you convert the substantial mass to solar sails? If the asteroids were made out of aluminum and mylar, it might be doable. But much of the asteroid material isn't amenable to being converted to solar sails. You would also need an extensive mining and manufacturing infra structure throughout the belt.

How big would the impactor sails be? Controlling a sheet of seran wrap many acres in area might be a problem. What would be the mechanism for hauling the sail in prior to impact?

And I don't get freezing the atmosphere in preparation for impact. With a normal atmosphere, a shock wave blasts away all the atmosphere above the tangent plane at point of impact. If the CO2 were frozen, it seems to me much less would be blasted away.

Hop_David
2010-Jan-24, 09:01 PM
T = 2*pi*sqrt(r^3/(G*m))
243 days = 2*pi*sqrt(r^3/(G*4.87e24 kg))
((243 days/(2*pi))^2*G*4.87e24 kg)^(1/3) = 1.5e6 km, about 5 light seconds, 4 times the distance to the moon, 0.01 AU, 1.4% of the distance to the sun.

And 1.5 times the distance to the Sun-Venus-L1 (or L2) which is about a million kilometers from Venus. A Venus synchronous orbit would be destroyed by the sun.

cjameshuff
2010-Jan-24, 10:47 PM
Even if you achieve high velocities, you will still need a substantial mass.

How will you convert the substantial mass to solar sails? If the asteroids were made out of aluminum and mylar, it might be doable. But much of the asteroid material isn't amenable to being converted to solar sails. You would also need an extensive mining and manufacturing infra structure throughout the belt.

A large part of the solar system is in fact made largely of aluminum oxides, asteroids included, plus the crusts of Mercury, Luna, and Mars. Silicon and silica may also be useful sail materials, alone or combined with aluminum. And considering the much higher higher impact energy per unit of impactor mass and the more efficient transfer of that energy to the material to be blasted away, a given mass of sail could far outperform the same mass of more conventional impactor. And yes, you would need absurd amounts of infrastructure and material to make the sails, which could be put to vastly more productive uses. Your argument suggests you believe I think it's a good idea, which means you obviously haven't been reading my posts on the subject.



How big would the impactor sails be? Controlling a sheet of seran wrap many acres in area might be a problem. What would be the mechanism for hauling the sail in prior to impact?

The sails would likely be some optimal mass for coupling with the piled up atmosphere...they would be as large as possible for that mass to maximize kinetic energy. I make no attempt to estimate either of those numbers.

Of course controlling them will be difficult, but there's no reason to think it's impossible, and there's numerous possible approaches to control. And I'm not sure why you think rolling it up into an impactor is a significant issue if the sailcraft itself can be built and flown. It's not like you'll be unfolding it again or have to avoid damaging it...for one possible approach, you could loosely crumple it using the lines or spars used to keep its shape, and then heat it to the point of melting, allowing surface tension to draw it together into a relatively high density projectile.



And I don't get freezing the atmosphere in preparation for impact. With a normal atmosphere, a shock wave blasts away all the atmosphere above the tangent plane at point of impact. If the CO2 were frozen, it seems to me much less would be blasted away.


An alternative approach...do the deep freeze, pile the frozen atmosphere up in mountains so a given impact can more efficiently blast it away,

Please, try to read posts more completely. You are raising objections that are answered already, sometimes even in the post you're replying to, or you're arguing against positions that haven't been taken.

Hop_David
2010-Jan-25, 02:03 AM
A large part of the solar system is in fact made largely of aluminum oxides, asteroids included, plus the crusts of Mercury, Luna, and Mars. Silicon and silica may also be useful sail materials, alone or combined with aluminum. And considering the much higher higher impact energy per unit of impactor mass and the more efficient transfer of that energy to the material to be blasted away, a given mass of sail could far outperform the same mass of more conventional impactor.

A conventional impactor could hit Venus at around 84 km/s max.

A 100 km/s impactor hitting Venus head on would hit at 135 km/sec. For the retrograde solar sail to hit Venus head on, its perihelion would have to be near Venus. If it had a perihelion at .2 AU, it wouldn't hit head on but at an angle. So I regard the 135 km/s as stretching it, but I will call max solar sail velocity 135 km/s

(135/84)^2 is 2.58. Less than triple the kinetic energy. To get a nice reflective mirror, you'd need high grade aluminum. Do you think .387 of the asteroid belt mass is aluminum?

I haven't heard of solar sails made of silicates.


And yes, you would need absurd amounts of infrastructure and material to make the sails, which could be put to vastly more productive uses. Your argument suggests you believe I think it's a good idea,

Huh? I don't think anyone here takes the idea seriously (except maybe the OP, Jonfr)


which means you obviously haven't been reading my posts on the subject.

Well, I did read this:


In terms of energy and material resource usage, all it involves is making vast amounts of solar sail material. It's roundabout, but seems likely to be one of the more efficient approaches.

I believe it's one of the less efficient approaches.

That is not suggesting that you think it's a good idea. Don't try to pin that straw man on me.


The sails would likely be some optimal mass for coupling with the piled up atmosphere...they would be as large as possible for that mass to maximize kinetic energy. I make no attempt to estimate either of those numbers.

Of course controlling them will be difficult, but there's no reason to think it's impossible, and there's numerous possible approaches to control. And I'm not sure why you think rolling it up into an impactor is a significant issue if the sailcraft itself can be built and flown. It's not like you'll be unfolding it again or have to avoid damaging it...for one possible approach, you could loosely crumple it using the lines or spars used to keep its shape, and then heat it to the point of melting, allowing surface tension to draw it together into a relatively high density projectile.

I make no attempt either. So who knows the size of the sail. The size of Texas? or merely Rhode Island? As the spars or support structures extend many kilometers they will need to be more robust. Thicker support structure would harm area to mass ratio.

Would the sail be turned by gryoscopes? Any pressure applied by the gyroscopes would travel down the spars at the speed of sound. And these same spars will pull the many square kilometers into a compact ball just before impact?

Mass drivers on Venus' surface would be reusable, much simpler and use less materials than this rube goldberg scheme, in my opinion.


An alternative approach...do the deep freeze, pile the frozen atmosphere up in mountains so a given impact can more efficiently blast it away,

What would be the critical slope of your CO2 mountain be? How high do you think you could pile this mountain?

Do you realize the atmosphere above the tangent plane at point of impact is a vast amount of atmosphere?

Given an impact on a planet's surface, 2 pi steradians, or a hemisphere of the ejecta are sent into the planet and don't achieve escape velocity. Only stuff lieing in the upper hemisphere of the blast is sent away. If the atmosphere is frozen out, this will be precious little even if you manage to pile absurdly high mountains.


Please, try to read posts more completely.

The same to you.


You are raising objections that are answered already, sometimes even in the post you're replying to

nope.


or you're arguing against positions that haven't been taken.

And nope.

Hop_David
2010-Jan-25, 02:36 AM
My suggestion was for suggested the sail to carry no payload whatsoever, consisting only of the sail and control equipment, minimizing sail loading and maximizing velocity. It would haul in the sail before impact, with the entire vehicle forming the impactor.

Actually your suggestion was ambiguous. Part of it stipulated "smaller impactors thrown from sailcraft" which implies impactors separate from the sail craft.


...use smaller impactors thrown from sailcraft on fast solar flyby trajectories. The projectiles could be little more than a sail, guidance systems, and some equipment to haul the sail in before impact, the whole thing serving as the projectile...

Before assuming I haven't completely read your post, you might take the time to read what you wrote.

neilzero
2010-Jan-26, 06:59 AM
Perhaps the Murphy shade solar energy collector can power the Kuo air plow. I had not thought of either idea before. The right combination of ideas may get the job done in a million years or less at almost infinite cost. The CO2 molecules traveling less than about 10 kilometers per second (with respect to Venus) will stay in the inner solar system, and be captured by Earth, Venus and briefly by Mercury and Earth's moon at perhaps one part per billion per century, but that should not cause much mischief?
I agree multi purpose projects such as Venus carbon to build habitats in space improve the possibility of be making the venture profitable in the very long run. The Kuo air plow can perhaps be oriented, so that Mars captures 1% of the expelled CO2 molecules per century? Neil

IsaacKuo
2010-Jan-26, 05:51 PM
The CO2 molecules traveling less than about 10 kilometers per second (with respect to Venus) will stay in the inner solar system, and be captured by Earth, Venus and briefly by Mercury and Earth's moon at perhaps one part per billion per century, but that should not cause much mischief?
CO2 molecules traveling less than 10km/s will simply fall back onto Venus. They would be on elliptical orbit paths which cross Venus's atmosphere.

CO2 molecules with greater than 10km/s will end up in a torus region around Venus's orbit. They would eventually be captured again by Venus, except that sunlight applies an outward pressure to let them escape the region before that happens. Some ignorable fraction of those molecules will be captured by Earth and Mars.

To expand on the "air plow" idea, there would be many air plows, all in a modified retrograde solar orbit. Each would encounter Venus about twice per Venusian year (about three times per Earth year). The relative velocity is around 70km/s, so a slope of 1:7 or greater is needed to impart escape velocity to the air.

The Kuo air plow can perhaps be oriented, so that Mars captures 1% of the expelled CO2 molecules per century?
I doubt it.

phunk
2010-Jan-26, 06:12 PM
I like the plow idea, but I suspect it would take a huge number of them working for a very long time to make significant progress.

Could nitrogen or CO2 be used as fuel in an ion engine? Maybe the plows could be solar powered and self-refueling.

IsaacKuo
2010-Jan-27, 06:42 AM
I like the plow idea, but I suspect it would take a huge number of them working for a very long time to make significant progress.
Yeah, no kidding. I haven't felt like calculating it out, but it's obviously going to take a lot more "stripping events" than those huge impactors since it only dumps a fraction of the air plow's energy per encounter.

Could nitrogen or CO2 be used as fuel in an ion engine? Maybe the plows could be solar powered and self-refueling.
If you want to use an ion engine like this, then you want to use something in Venus orbit rather than solar orbit. This would be a solar electric ramjet flying in a slightly modified polar orbit along Venus's terminator. With an intake speed of 7km/s and an exhaust speed of 17km/s, the exhaust itself is what escapes Venus's gravity well.

This idea would not be practical for the air plow, because the air plow flies through the atmosphere at 70km/s. You'd need an exhaust velocity greater than 70km/s; probably much greater is required. On the other hand, using solar sails for thrust are a good fit. Solar sails give essentially a constant amount of thrust, so they are more efficient when the speed is faster. (The rate of added kinetic energy is proportional to the speed.)

So, the air plow would spend perhaps a few days furling and unfurling the sail for the brief Venus encounter, with about a hundred days in between encounters using the sail to regain lost speed.

Hop_David
2010-Jan-27, 06:31 PM
Yeah, no kidding. I haven't felt like calculating it out, but it's obviously going to take a lot more "stripping events" than those huge impactors since it only dumps a fraction of the air plow's energy per encounter.

I find the plow idea interesting. But it has a very abusive environment. Atmospheric abuse scales roughly with velocity cubed.

If you enter Venus atmosphere from a retrograde orbit, velocity will be 35 km/s or more. A sled designed for multiple re-use would have to be extremely tough.

I like the notion of using earth-Venus cycler sleds. The earth Venus synodic period is very close to 1.6 years. The period of an Earth-Venus Hohmann is .8 years. This makes a nice system of Hohmann cyclers possible. The departure and arrival points form the corners of cosmic pentagrams.

The act of diving deep into Venus' gravity well and skimming through the upper atmosphere would damage the orbit. However an Earth Venus cycler repeats its cycle every 8 years. Perhaps repairing it's orbit in 8 years time is possible with ion engines or a solar sail of modest size.

With this scheme, the scoop would enter Venus' atmosphere at around 11 km/sec. High, but not nearly as tough as 35 and greater.

A cycler could drop off a payload at Sun-Earth-L1. From there it could make it's way to the moon and cislunar space via a low Delta V Belbruno path. At those locations there might be a market for CO2, nitrogen and sulfur.

IsaacKuo
2010-Jan-28, 02:44 PM
My assumed airspeed of 70km/s is pretty high, of course, but perhaps not too much higher than the Galileo atmospheric entry probe. It lost about 45mm of heat shield in less than two minutes.

This suggests that the air plow should be a thick and heavy slab with a wedge nose. For a given frontal area, the mass loss is roughly constant (radiative heat transfer is the same for a given temperature) but the amount of air that may be plowed is proportional to the plow's overall mass.

But of course, a thick heavy slab would need to unfurl a huge area of solar sail...

GOURDHEAD
2010-Jan-28, 04:35 PM
I suggest the following:
We know some of the hazards associated with space travel awaiting us, but it is reasonable to assume that we are not aware of all of them; therefore, we must design systems that afford degrees of safety and comfort with sufficient margins to minimize the occurrence of hazards, optimize responses to them, and provide reasonable comfort. Humans experiencing discomfort are less competent at anticipating hazards and responding adequately to them, thus safety and comfort are coupled.

Large amounts of energy will be required to do serious terraforming of any off-Earth site, and Earth’s energy resources will be ever more stressed as days go by. The more sites we colonize; the more sites we must attempt to protect from hazards leading to ever increasing energy requirements. Fortunately, the sun has copious amounts of energy that we can harness to accomplish the tasks required to colonize, including heating of the remote sites (Mars and beyond), as many objects as we wisely choose. The harnessing of this solar energy can be accomplished by placing power beam generators in polar orbit about the sun in orbits inside that of Mercury as close to the sun as the leading edge of material science and magnetic shielding technology can accommodate. The solar polar orbits are suggested to reduce the incidences of occultation and to facilitate the management of the beams to avoid inadvertent irradiation hazards to populated sites. These stations will output highly collimated beams of microwave (or whatever portion of the electromagnetic spectrum proves most compatible to the set of design constraints imposed by generation, collimation, aiming, and reception by photovoltaic receivers in the target areas) radiation at levels of from 10^16 to 10^20 watts. Due to the proximity of these stations to the surface of the sun, protection from coronal mass ejections and the associated irradiation will be a challenge. Magnetic and material shielding will be a must. Bringing the first one on line will take ~200 years after startup to transport the tons of material required to assemble them at locations near the sun, then it will be used to speed up the process by powering subsequent transportation of materials to the selected power beam generator sites.

The functions assigned to the outputs of various power beam generators will be dedicated to one of the following:
1. Major transport vehicle.
2. Terraformation/colonization targets—may require more than one per target.
3. Venus for harvesting CO2 and N2 and transporting them to sites to be terraformed.
4. Propellant provider beam support.
5. Asteroid/comet deflection/destruction to protect colonized sites.
These energy harvesting and delivery devices will be the mainstay for solar system exploration and terraforming and colonization.

Once a sufficient number of power beam generators are in place near the sun, energy will be available to be beamed to Venus and power CO2 extraction processes using ionization and particle beaming the particles to orbiting collection stations. Once out of the Venusion atmosphere appropriate amounts of CO2 can be shipped to the moon and Mars to provide atmospheres for each. Meanwhile appropriately modified microbes can be working to transform the H2SO4 into water and sulfites and sulfates.

The power beam generators with giga-giga watt capability are needed to do this job in a safe and comfortable way. Once in place the power beams can be used for terraforming as many other sites as we wish with the power beams protecting them from comet an asteroid collisions. Now is a good time to start since most nations need a useful make work project to help them climb out of a sparse job environment.

Murphy
2010-Jan-29, 02:41 AM
My assumed airspeed of 70km/s is pretty high, of course, but perhaps not too much higher than the Galileo atmospheric entry probe. It lost about 45mm of heat shield in less than two minutes.

Wouldn't that be a bit of a problem though? That means that every scoop you send will dump a small amount of heat shield into the Venusian atmosphere. After millions or billions of encounters (or how ever many is required) there'd be a hell of a lot of left over particles of heat shields, maybe millions of tonnes of the stuff in the atmosphere or on the ground, you'd have to somehow clean that up to. I've no idea about the amount of material we're talking about, but that might be something you want to consider.

IsaacKuo
2010-Jan-29, 02:53 PM
Wouldn't that be a bit of a problem though? That means that every scoop you send will dump a small amount of heat shield into the Venusian atmosphere. After millions or billions of encounters (or how ever many is required) there'd be a hell of a lot of left over particles of heat shields, maybe millions of tonnes of the stuff in the atmosphere or on the ground, you'd have to somehow clean that up to. I've no idea about the amount of material we're talking about, but that might be something you want to consider.
I presented the idea as an alternative to using impactors to strip away Venus's atmosphere. That idea also dumps millions of tons of stuff onto Venus.

Since most or all of us here don't really think of this as a practical thing to do in any case, I don't think any of us have put much thought into all of the asteroidal litter left on/near the surface of Venus.

Hop_David
2010-Jan-29, 05:34 PM
My assumed airspeed of 70km/s is pretty high, of course, but perhaps not too much higher than the Galileo atmospheric entry probe. It lost about 45mm of heat shield in less than two minutes.

This suggests that the air plow should be a thick and heavy slab with a wedge nose. For a given frontal area, the mass loss is roughly constant (radiative heat transfer is the same for a given temperature) but the amount of air that may be plowed is proportional to the plow's overall mass.

But of course, a thick heavy slab would need to unfurl a huge area of solar sail...

I can understand big speeds when the goal is atmospheric erosion via impacts. Bigger speeds mean you can get a lot more kinetic energy for less mass. And availability of impactor mass could be a show stopper for the impactor scheme.

But why the big velocities for the air plow? Once it scoops up a load of atmosphere, it only takes 11 km/sec to get it out of Venus' neighborhood.

If you hit Venus at 70 km/sec, that's 6 times the momentum that must be regained via sail, ion engine, or whatever provides the delta V.

And abuse from atmospheric drag scales with the cube of velocity. 6^3 is 216. More than 200 times the abuse is something to consider if you want the plow to be reusable.

IsaacKuo
2010-Jan-29, 07:43 PM
But why the big velocities for the air plow?
It seems to be the best fit for the job, at least with solar sails.

Once it scoops up a load of atmosphere, it only takes 11 km/sec to get it out of Venus' neighborhood.
If we're talking about scooping up a load of atmosphere, then that's a different idea. I actually like the idea of atmospheric scooping, or aeroscooping, more than merely plowing air away. With scooping, you get to do something useful with all that carbon and oxygen. You could, for instance, build space habitats out of graphite (which, as you know, I prefer over planetary habitats).

But you've got a lot of different issues going on with atmospheric scooping. Since you're scooping up air, you've got to deal with the compression heat, meaning you're limited to the rate at which you can refrigerate the carbon dioxide. For this sort of thing, the best fit is a circular orbit within the upper atmosphere and flying along the terminator for 24/7 solar power, processing air 24/7.

If you hit Venus at 70 km/sec, that's 6 times the momentum that must be regained via sail, ion engine, or whatever provides the delta V.
Actually, you get less momentum loss for a given amount of plowed air. You can always adjust the skimming altitude to adjust the amount of air encountered higher or lower and/or fanning out the "plow angle". Depending on the shape of the plow's nose, it may either plow away a narrow wedge directly above its flight path or it may plow away a wide cap above its flight path.

For a given amount of kinetic energy loss, the faster you go, the less momentum you lose. For a solar sail, faster is better. For an ion engine, this isn't the case because your speed affects the cost of propellant.

And abuse from atmospheric drag scales with the cube of velocity. 6^3 is 216. More than 200 times the abuse is something to consider if you want the plow to be reusable.
The abuse evens out, I think. The amount of air you plow away per second is also proportional to the cube of the velocity.

neilzero
2010-Feb-02, 04:11 AM
~This was suggested Oct 11, 2009 in life in space in a long thread (Making Venus livable) with lots of great ideas. Xyvoid typed~ I would suggest we bioengineer an organism to do this for us. Possibly a photosynthesis plus sulfate reducing 'bacteria' that creates a plastic byproduct which would sequester both carbon and sulfur from the atmosphere. An example plastic is Polyphenylene sulfide which resists heat, acid, and abrasion allowing it to survive the trip to the surface and remain there.

It is already possible to make the bacteria create the plastic with current tech and likely also one that could survive and float in the Venus atmosphere. This seeding would be very cheap and would result is decreased atmospheric pressures reduce the greenhouse effect and make the atmosphere more breathable allowing a reduction in temperature. With only the cost of sending a probe to Venus and developmental costs which likely could be done with millions of dollars rather than the quadrillions some of the other plans would need.

For more immediate colonization why not make floating arcologies(sp?) solar power would be abundant, floating would be simple in the dense atmosphere and all the main things required to sustain humans could be pulled right out of the air, carbon, hydrogen, nitrogen, oxygen and sulfur. All we would need to keep humans alive would be metals like iron, zinc and some other elements in small quantities. The rest we create using the surplus solar energy.

Recent solar panel advances in plastic panels, no silicon required, would allow more panels to be created on Venus. although current efficiency levels are around 5% ~There likely is not enough sulfate for more than 5% of the carbon dioxide, but every little bit helps. Neil~

Van Rijn
2010-Feb-02, 07:51 AM
~This was suggested Oct 11, 2009 in life in space in a long thread (Making Venus livable) with lots of great ideas. Xyvoid typed~ I would suggest we bioengineer an organism to do this for us. Possibly a photosynthesis plus sulfate reducing 'bacteria' that creates a plastic byproduct which would sequester both carbon and sulfur from the atmosphere. An example plastic is Polyphenylene sulfide which resists heat, acid, and abrasion allowing it to survive the trip to the surface and remain there.

It is already possible to make the bacteria create the plastic with current tech and likely also one that could survive and float in the Venus atmosphere. This seeding would be very cheap and would result is decreased atmospheric pressures reduce the greenhouse effect and make the atmosphere more breathable allowing a reduction in temperature.


Again: If you want to terraform Venus, a straight biological approach won't work.

Do you understand that the Venusian atmosphere is massive and nearly all CO2? (Nitrogen is the only other significant constituent).

Do you understand that (if it were possible) splitting the carbon and oxygen of that massive atmosphere would result in a lethal high pressure oxygen atmosphere?

Do you understand that there are only trace amounts of water in the Venusian atmosphere?

Even if you had a bug that could sequester both the carbon and oxygen of the atmosphere, it would also have to do it without adding hydrogen, or the bugs would run out of water before they made a dent in the CO2. Adding sulfur to the mix would be an additional constraint, given the trace amount of sulfur available.

neilzero
2010-Feb-22, 09:46 AM
Yes, Van Rign, I understand too much oxygen is worse than too much carbon dioxide. Earth has about 4 millibars of carbon dioxide, Venus has about 80,000 millibars of carbon dioxide = 20,000 times too much. For humans Venus should have 210 millibars of oxygen, which bugs can release from about 300 millibars of carbon dioxide. 1000 millibars of oxygen may be about right as some of the oxygen will combine with surface soil and rock. At 31 degrees c, some of the excess nitrogen will also be absorbed by rock, soil and oxygen, plus humans can possibly tolerate 2000 plus millibars of nitrogen if the oxygen is close to 210 millibars. If we have oceans of liquid carbon dioxide at 31 degree c, we still have several thousand millibars too much carbon dioxide, but perhaps we can cope with a simple air mask, or a prosthesis to remove carbon dioxide from our blood. We are now trapped at a delicate ballance: Less pressure and the the liquid carbon dioxide will boil. Cooler than 31 c and the liquid carbon dioxide oceans will freeze, and the solid will sink to the bottom as solid carbon dioxide has higher density than liquid. Most plant life will be happy with 210 millibars of oxygen and 31 degrees c, even if the carbon dioxide is several thousand millibars. 31 degree c is near perfect for naked humans. Liquid water will float on top of the liquid carbon dioxide, but the water will have lots of dissolved carbon dioxide, so we will burp a lot from drinking it, when we are in our lower pressure habitats. The cities in the upper atmosphere will still be buoyant with breathing air, but not as buoyant as with 90% carbon dioxide. The main remaining problem is the sulphuric acid which will fall as rain when we lower the temperature. Presently it evaporates before it hits the surface. According to one post, the sulphuric acid decomposes, but I'm doubtful about that, as there is not presently enough free oxygen to reform sulphuric acid. Neil

Van Rijn
2010-Feb-24, 11:59 PM
. If we have oceans of liquid carbon dioxide at 31 degree c, we still have several thousand millibars too much carbon dioxide, but perhaps we can cope with a simple air mask, or a prosthesis to remove carbon dioxide from our blood.


To get surface temperatures down to that temperature, nearly all sunlight would need to be blocked from the surface. The sunblock would need to remain until the CO2 was removod or sequestered, or you'll just get a thick atmosphere again.



Liquid water will float on top of the liquid carbon dioxide, but the water will have lots of dissolved carbon dioxide, so we will burp a lot from drinking it, when we are in our lower pressure habitats.


What water? You seem to be ignoring the fact that there is CO2, there is some nitrogen, but only a trace of water on Venus.



Presently it evaporates before it hits the surface. According to one post, the sulphuric acid decomposes, but I'm doubtful about that, as there is not presently enough free oxygen to reform sulphuric acid. Neil

This is another trace component in the Venusian atmosphere. It isn't clear to me why you are focusing on it.

Bluevision
2010-Feb-26, 04:37 AM
What water? You seem to be ignoring the fact that there is CO2, there is some nitrogen, but only a trace of water on Venus.Just wondering, how much H2SO4 is there in the atmosphere? You always hear about how Venus has Sulphuric Acid rain. Would it not be possible to change that into H2O and Sulfur, the former being stored for a cooler planet, and the latter being pumped into the upper atmosphere to block sunlight? I'm guessing either bioengineered microbes or factories in floating colonies could pull that off, if it's possible.

I'm pretty sure that either way you draw it, Venus is going to have a pretty different way of life than Earth, or even Mars, is. It has an extremely slow rotation and would take a huge amount of energy to get it to near-Earth like conditions. I think it'd be acceptable for it to have a relatively dense atmosphere (I'm not sure what % of Earth's pressure to go on exactly, or what a human could reasonably survive in, or what a human, either bioengineered or just raised in a higher-pressure environment, could survive in,) and a still rich CO2 atmosphere, though the introduction of large-scale forests would lower CO2 and raise O2 at least a bit.
With all those issues to human life though, a CO2-rich atmosphere would be quite good for plant life, probably even allowing them to thrive in warm conditions that would also be incredibly moist if there was adequate water. The only problem I see is the rotation of the planet; how would plants fare with an 100-day Venusian night (assuming we can find a way to actually spin it twice as fast as it is currently,) and how would that slow rotation affect heat distribution, oceans, life forms, etc. Would all the plants just sort of go into hibernation like they do on Earth? If you add complex lifeforms into the mix, things get even cooler and trippier. I'll have to ponder a lot on this, but the images I'm getting off the bat are really, really awesome to say the least.

If someone could answer the Sulphuric Acid question though, I'd appreciate it :)

neilzero
2010-Feb-26, 12:28 PM
Let's guess one cubic kilometer of sulphuric acid dissolved in one cubic kilometer of water = mass about 3.5 billion tons = For a planet = not much, but a big engineering project and very unpleasant on your skin and in your lungs. My guess is we need to sequester the sulphuric acid or it will mix with any free water we bring to Venus. I think there are some microorganisms that drink dilute sulphuric acid and poop sulpher, so that is a possibility, after we cool Venus to about 100 degrees c = 212 f.
I agree we have to bring more hydrogen to Venus to make water out of the oxygen in the carbon dioxide. The sulphuric acid does not have enough hydrogen to make Venus Earth like, or even tolerable. Neil

Bluevision
2010-Feb-26, 11:44 PM
Let's guess one cubic kilometer of sulphuric acid dissolved in one cubic kilometer of water = mass about 3.5 billion tons = For a planet = not much, but a big engineering project and very unpleasant on your skin and in your lungs. My guess is we need to sequester the sulphuric acid or it will mix with any free water we bring to Venus. I think there are some microorganisms that drink dilute sulphuric acid and poop sulpher, so that is a possibility, after we cool Venus to about 100 degrees c = 212 f.
I agree we have to bring more hydrogen to Venus to make water out of the oxygen in the carbon dioxide. The sulphuric acid does not have enough hydrogen to make Venus Earth like, or even tolerable. NeilThat equation at the start is dissolved not turned into though, right? Does anyone know much water could be gotten from actually transforming all the H2SO4 into H2O and S8? And Sulphur would make a good solar shield, right?

Microorganisms are probably the best bet in a long-term terraforming scenario, but early on floating cities could also mechanically transform Sulphuric Acid into water as an alternative to shipping it in large quantities from Earth or somewhere else.

Cooling Venus below the boiling point would really be a huge achievement. If that can be reached, it probably wouldn't be much more to take it down to an acceptable average 30 degrees C or around there (I think that's the best to shoot for.)

neilzero
2010-Sep-22, 04:13 AM
~Here are shortened versions of comments about the carbon dioxide of Venus cooling the surface. My comments are enclosed with~
What would be the possibility of creating a heat shield in front of the planet to deflect a lot of the suns energy? ~advanced technology can do that and it is less costly than getting a magnetic field for Mars, except possibly a huge super conducting coil~ Would it be easier to do than starting a magnetic field on Mars with asteroids captured and then sent on a collision path? We landed a sat on I think eros? So landing an engine on an asteroid and having it hit a planet shouldn't be too difficult. ~we can do that, but near term the engine changes the course of the asteroid by a negligible amount even for asteroids and comets with dimensions of about ten meters~ but would trying to increase Mars size and possibly start its core up again be worth the effort over trying to build a heat shield *something we will need one day for earth* for Venus?~I agree we should do pilot program heat shields for Earth as quickly as possible, even though effective is likely centuries in the future. The device is called a staytite~

Increase Mars size?

If these are ever possible, it's safe to say they are centuries away. Currently we only have the tech capabilities to send a van-sized probe to most planets. Perhaps if we put in a big investment and used a light material like a foil sail such as the Japanese recently launched, we might be able to send something maybe 1km across. But even that's a stretch.

As to deflecting asteroids, the closest we could come is launching an ion engine and slowly adjusting the orbit of asteroids to collide with Mars. But I'm not sure There likely is not enough material in the asteroid belt to send to Mars to re-melt its core, and that's if you assume we can throw Ceres and Vesta at it, which we definitely don't have the tech to pull off.

You also have to take into account that the transfer of orbital energy from the asteroids to the planet (which is one of the prime factors in planetary melting) would quickly be cancelled out by heat loss from the planet's surface. So not only would you have to move a titanic quantity of material, which may not even exist in our solar system, but you'd have to bombard it in rapid succession to affect any measurable change in internal planetary temperature.

I'd be setting myself up for failure if I predicted that we'd never be able to do it.

Imagine our Sun shield craft included a nuclear generator, huge argon plasma engines and unlimited fuel from an Earth resupply route. That is technology possible now and R&D could do even better.

Get much closer to Sol and shade all of Venus using a much smaller shade and serious thrusting to maintain position. ~A sun shade 1,400,000 kilometers in diameter close to the sun could block nearly all the sunlight at Venus, The trusting energy to keep it in place would be huge~

On a separate idea then maybe the best starting idea for terraform Mars is to add carbon dioxide.

A good place to find this gas is Venus and removing gas there would help Venus too.

This is way beyond what we can do now but imagine many craft dragging kilometer wide balloons of carbon dioxide between Venus and Mars.

Warning Mars would do many good things and gas is ~not~ easier to move than rock.

Maybe start in about 150 years time.

I once read that you could build a base station that would 'float' on Venus' atmosphere and that the pressure and temperature would be very Earth Like. I don't remember where I read it, but it claimed that building a sealed base would sink in the Venusian atmosphere until pressure reached about 1.3x that of Earth and would then float there. The article also said that at that height the temperature would be around 80 degrees c. ~It is about 80 degrees f some what higher where the air pressure is about the same as the top of Mount Everest. But the colonies can float there if the humans breath about 90% oxygen~ Couple that with the idea of growing algae for food to convert CO2 to oxygen.

Except you would need an awful lot of Prozac to get through one 5832 hour Venusian night...just ask an Inuit.

You might find this interesting:
Venus Atmosphere Temperature and Pressure Profiles:
http://www.datasync.com/~rsf1/vel/1918vpt.htm

Earth equivalent pressure is at 49.5km (30.8mi)

The temperature at 54km (34mi) is a comfortable 68F. ~ somewhat higher and not quite that cool according to a graph from a different source, but doable~

So somewhere around 50 to 55 km above Venus, the temperature/pressure is reasonably Earth-like. Unfortunately that's right in the middle of sulfuric acid clouds. ~according to another source the sulphuric acid is somewhat lower~

How do they know the heat on Venus is not caused by radioactive decay in the core? ~Much less than one degree c of Earth's surface temperature is due to radioactive decay in Earth's core, but possibly that is several degrees for the Venus surface~

Well there is also the possibility of a Sulfur cycle on Venus where you start with the surface melted and high volcanism. That sends a lot of Sulfur Dioxide into the atmosphere which reflects sunlight which allows the surface to solidify (granted still very hot due to the atmosphere being 95% Carbon Dioxide and 90 times thicker than the atmosphere of the Earth). The Lithium ~can someone explain the role of lithium?~ grows with time cutting off the volcanoes and the supply of Sulfur Dioxide. With time the Sulfur levels drop and the surface can then remelt.

Eventually ~5 billion years and then too cold?~ Venus will move into the "goldilocks zone" as its orbital distance from the sun increases, just as Earth one day will move out! I would like to think that Venus will one day host a biosphere similar to that of the earth, it all depends on the sun and it's longevity though.

Sorry to be a downer but last I check Venus is moving closer to the sun. Though it was likely in the habitable zone billions of years ago.
You may be confused due to the behavior of the Moon.

No it really won't. The problem is that it has a lot of Carbon Dioxide and almost no water vapor. There are only 3 ways to scrub Carbon Dioxide from an atmosphere 1) biological (aka photosynthesis), 2) dissolving into water and going into an ocean (this is what happened for the earth, but with no water on Venus...), and 3) being removed from the atmosphere by either the solar wind or asteroid impacts which is tough to do for Venus.

The bottom line is that even if Venus were in our orbit it would still not be habitable.
Venus ~may~ not be getting closer to the sun; the sun is slowly getting brighter (but very slowly). 4 billion years ago it was about 30% dimmer which means that the "habitable zone" would have been closer to the sun then, although most scientists have it too narrow as atmospheric conditions are what are really important not just proximity to the sun.