Venus

SpaceNut · 2015-07-19 21:05:07

The aeroplankton comprises numerous microbes, including viruses, about 1000 different species of bacteria, around 40,000 varieties of fungi, and hundreds of species of protists, algae, mosses and liverworts that live some part of their life cycle as aeroplankton, often as spores, pollen, and wind-scattered seeds.

Lots of variety but it seems that these are all in the lower atmosphere or near Everest altitudes but we are talking way higher than that...

I was thinking about the poles and in terms of the sun shading to create ice caps. One could completely block the sun over areas with a shield and since venus spins so slowly we can induce seasons with the same shield by simply changing what gets blocked.

RobertDyck · 2015-07-19 21:46:52

Venus cloud layer has about 1 atmosphere pressure, so higher pressure than Everest. Even though altitude is higher. That's because Venus has surface pressure of 92 bars, and 90% of Earth's gravity.

Tom Kalbfus · 2015-07-25 11:16:05

One Idea I had recently is to place a mirror at Sun-Venus L1, another mirror at Sun-Venus L1, and a ring mirror in a Polar sun facing orbit around Venus. So days and nights are created this way. The Sun shines on Mirror L1 which deflects light away from Venus, as a diffusing lens, some of the light hits the ring mirror around Venus which then bends the light towards the L2 mirror, which then reflects the light on what would be the night side of Venus. The shutters in the L1 Mirror open and close on a 24 hour cycle to produce night and day for the entire planet at once! During night, the entire planet is in shadow and experiences night, that way we don't have to mess with Venus' rotation, the Sun winks on and then off, where ever it happens to be in the sky of Venus. In this model, the poles will be cooler than the equator.

knightdepaix · 2015-07-27 17:56:38

Tom Kalbfus wrote:

Venus atmosphere is much more massive than Mars, it would probably be warmed by only a tiny amount. Venus doesn't need nitrogen however, but it does need hydrogen. Hydrogen doesn't freeze solid at Pluto's surface, so any Hydrogen we hurl at Venus will have to be in a container, the container would vaporize upon impact letting loose the hydrogen, maybe the heat generated with disassociate some carbon-dioxide molecules so the hydrogen could combine with oxygen to make water. Carbon lacking a partner would fall to the surface.

GCNRevenger wrote:

But yet we are willing to vent Hydrogen as a waste byproduct onboard the ISS from the russian oxygen unit into space.
But this Hydrogen is worthless.
Plus, getting electricity from the Moon 240,000mi away, when the Earth does not spin in synch with the Moon, and getting the energy through EARTH'S atmosphere, oh yes and solar flares frying the Lunar arrays and transmission gear...
Power from the Moon I think is a pipe-dream excuse, not ideal in the least. The only things that the Moon canprovide from Earth are metals, He3, and as a base of operations for spaceflight way WAY down the road.

If helium-3 fusion energy generation became reality, would the 2 moles hydrogen atoms/protons or 1 mole hydrogen gas exhaust be useful to make water and carbon with Venus atmospheric carbon dioxide. Both the carbon and oxidane (water) could then be sent to Mars.

Tom Kalbfus · 2015-07-27 21:49:31

knightdepaix wrote:

Tom Kalbfus wrote:
Venus atmosphere is much more massive than Mars, it would probably be warmed by only a tiny amount. Venus doesn't need nitrogen however, but it does need hydrogen. Hydrogen doesn't freeze solid at Pluto's surface, so any Hydrogen we hurl at Venus will have to be in a container, the container would vaporize upon impact letting loose the hydrogen, maybe the heat generated with disassociate some carbon-dioxide molecules so the hydrogen could combine with oxygen to make water. Carbon lacking a partner would fall to the surface.
GCNRevenger wrote:
But yet we are willing to vent Hydrogen as a waste byproduct onboard the ISS from the russian oxygen unit into space.
But this Hydrogen is worthless.
Plus, getting electricity from the Moon 240,000mi away, when the Earth does not spin in synch with the Moon, and getting the energy through EARTH'S atmosphere, oh yes and solar flares frying the Lunar arrays and transmission gear...
Power from the Moon I think is a pipe-dream excuse, not ideal in the least. The only things that the Moon canprovide from Earth are metals, He3, and as a base of operations for spaceflight way WAY down the road.
If helium-3 fusion energy generation became reality, would the 2 moles hydrogen atoms/protons or 1 mole hydrogen gas exhaust be useful to make water and carbon with Venus atmospheric carbon dioxide. Both the carbon and oxidane (water) could then be sent to Mars.

It would be easier to send the gases you need from Pluto, the total delta-V from Pluto and Pluto's orbit is around 7 km/sec. Escape Velocity from Pluto is 1.22 km/sec + Pluto's orbital velocity of 4.74 km/sec and add 1 km/sec for good measure. Assume it has to travel 40 AU to get to Venus and Mars, and it will take 6000000000 seconds for the materials to reach Mars and Venus, which is 190 years, total delta-v is 6.96 km/sec, if you want it to take 95 years instead add one more km/sec for a total delta-v of 8 km/sec. still less than the escape velocity from Venus. I suppose there is much to be done with Mars and Venus before the arrival of those gases. You could start by melting the polar caps of Mars, shading Venus and letting it cool down some, that could take 95 years.

Antius · 2015-07-29 05:32:32

Ceres is much closer and would therefore be a much easier source of hydrogen than Pluto. It also has a relatively high rotation rate, meaning you can use its angular momentum to propel packages from a space elevator without the need for propellant. If a future colony governor is sitting on Venus trying to buy 1000 tonnes of hydrogen, you can bet he will buy it where it is cheapest. He won't be ordering it from Pluto just because it 'looks' more abundant.

Transporting materials from across the solar system will always be expensive and will only take place in relatively small amounts. It is most sensible to assume that Venus will remain hydrogen poor and look for solutions that allow you to work around it. Closed paraterraformed biospheres, recycling hydrogen with very high efficiency. Over geological timescales, enough hydrogen will leak from these structures to give Venus some modest reserve in the external environment.

Antius · 2015-07-29 06:20:37

This paper suggests that the Venusian mantle may be substantially more water rich than that of Earth and that this may have been directly responsible for preventing the formation of global tectonics on Venus.

http://onlinelibrary.wiley.com/doi/10.1 … 7/abstract

If true, this raises an intriguing possibility. If Venus were to be suddenly cooled to 250K, (i.e. by placing a sun-screen between it and sun) much of its atmosphere would liquefy onto its surface. As the surface cooled and contracted, enormous fissures would open, which would fill with liquid CO2, causing the surrounding rock to contract even further. If fissures reach the mantle there would be a surge in global volcanic activity, which would result in substantial water vapour entering the atmosphere. This would freeze out and would float as ice bergs on the liquid CO2 seas (ice is less dense than liquid CO2).

As time passed, more and more of the liquid CO2 would drain into porosities within the crust leaving behind the water on the planet’s surface.

Tom Kalbfus · 2015-07-29 07:22:49

Antius wrote:

Ceres is much closer and would therefore be a much easier source of hydrogen than Pluto. It also has a relatively high rotation rate, meaning you can use its angular momentum to propel packages from a space elevator without the need for propellant. If a future colony governor is sitting on Venus trying to buy 1000 tonnes of hydrogen, you can bet he will buy it where it is cheapest. He won't be ordering it from Pluto just because it 'looks' more abundant.
Transporting materials from across the solar system will always be expensive and will only take place in relatively small amounts. It is most sensible to assume that Venus will remain hydrogen poor and look for solutions that allow you to work around it. Closed paraterraformed biospheres, recycling hydrogen with very high efficiency. Over geological timescales, enough hydrogen will leak from these structures to give Venus some modest reserve in the external environment.

The mass of the oceans is approximately 1.35×10^18 metric tons, or about 1/4400 of Earth's total mass. The oceans cover an area of 3.618×108 km2 with a mean depth of 3682 m, resulting in an estimated volume of 1.332×109 km3.[136] If all of Earth's crustal surface was at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km.[137][138]
https://en.wikipedia.org/wiki/Earth

Mass of Earth's Oceans is 1.35x10^21 kg
Mass of Pluto is 1.290x10^22 kg
If 10% of Pluto's mass is water ice, then I'd say Pluto has enough water.
One fifth of water's mass is hydrogen and that would be 270,000,000,000,000,000,000 kg of hydrogen which needs to be sent from Pluto to Venus to make an ocean equal to Earth's.

The Mass of Ceres is 9.393x10^20 kg, I'm sure not all of it is water.
The escape velocity is 0.51 km/sec
The average orbital speed is 17.9 km/sec. So to escape Cere's gravity and eliminate its forward orbital velocity you need a delta-v of around 18 k/sec compared with just 8 km/sec for Pluto and to give it an inward velocity of 2 km/sec to hit Venus in 95 years. Also it appears that Ceres has only one tenth of the mass of Earth's Oceans. So as you can see Pluto has some obvious advantages, there is the 95 year journey sunward, but terraforming Venus is going to take longer than that anyway, the first step would be shading the planet and letting it cool. While you are building the shade at L1, you might also be mining Pluto for water, separating out the hydrogen and dumping the Oxygen left behind on Pluto's surface. You see, just like Nitrogen, oxygen is a solid on Pluto's surface, you would have nitrogen and oxygen glaciers after that. The energy to deliver the hydrogen from Pluto would be less than that from Ceres.

There is just one problem with dumping oxygen on Pluto's surface. Oxygen is an oxidizer, you make a large enough pile of it on Pluto, it will possible react with Pluto's surface, which contains a lot of carbon compounds. Maybe the oxygen should be sent to Mars, maybe dump some of it on Earth's Moon as well. I suspect that this amount of oxygen is way more than Mars needs to make its atmosphere breathable, and may in fact be too much! We could give the Moon an temporary Oxygen atmosphere with all this excess oxygen, it will leak into space, but we can dump enough on the Moon so that it stays there for a while anyway.

Last edited by Tom Kalbfus (2015-07-29 07:28:29)

Antius · 2015-07-30 12:04:41

Tom Kalbfus wrote:

Antius wrote:
Ceres is much closer and would therefore be a much easier source of hydrogen than Pluto. It also has a relatively high rotation rate, meaning you can use its angular momentum to propel packages from a space elevator without the need for propellant. If a future colony governor is sitting on Venus trying to buy 1000 tonnes of hydrogen, you can bet he will buy it where it is cheapest. He won't be ordering it from Pluto just because it 'looks' more abundant.
Transporting materials from across the solar system will always be expensive and will only take place in relatively small amounts. It is most sensible to assume that Venus will remain hydrogen poor and look for solutions that allow you to work around it. Closed paraterraformed biospheres, recycling hydrogen with very high efficiency. Over geological timescales, enough hydrogen will leak from these structures to give Venus some modest reserve in the external environment.
The mass of the oceans is approximately 1.35×10^18 metric tons, or about 1/4400 of Earth's total mass. The oceans cover an area of 3.618×108 km2 with a mean depth of 3682 m, resulting in an estimated volume of 1.332×109 km3.[136] If all of Earth's crustal surface was at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km.[137][138]
https://en.wikipedia.org/wiki/Earth
Mass of Earth's Oceans is 1.35x10^21 kg
Mass of Pluto is 1.290x10^22 kg
If 10% of Pluto's mass is water ice, then I'd say Pluto has enough water.
One fifth of water's mass is hydrogen and that would be 270,000,000,000,000,000,000 kg of hydrogen which needs to be sent from Pluto to Venus to make an ocean equal to Earth's.
The Mass of Ceres is 9.393x10^20 kg, I'm sure not all of it is water.
The escape velocity is 0.51 km/sec
The average orbital speed is 17.9 km/sec. So to escape Cere's gravity and eliminate its forward orbital velocity you need a delta-v of around 18 k/sec compared with just 8 km/sec for Pluto and to give it an inward velocity of 2 km/sec to hit Venus in 95 years. Also it appears that Ceres has only one tenth of the mass of Earth's Oceans. So as you can see Pluto has some obvious advantages, there is the 95 year journey sunward, but terraforming Venus is going to take longer than that anyway, the first step would be shading the planet and letting it cool. While you are building the shade at L1, you might also be mining Pluto for water, separating out the hydrogen and dumping the Oxygen left behind on Pluto's surface. You see, just like Nitrogen, oxygen is a solid on Pluto's surface, you would have nitrogen and oxygen glaciers after that. The energy to deliver the hydrogen from Pluto would be less than that from Ceres.
There is just one problem with dumping oxygen on Pluto's surface. Oxygen is an oxidizer, you make a large enough pile of it on Pluto, it will possible react with Pluto's surface, which contains a lot of carbon compounds. Maybe the oxygen should be sent to Mars, maybe dump some of it on Earth's Moon as well. I suspect that this amount of oxygen is way more than Mars needs to make its atmosphere breathable, and may in fact be too much! We could give the Moon an temporary Oxygen atmosphere with all this excess oxygen, it will leak into space, but we can dump enough on the Moon so that it stays there for a while anyway.

Problem is that unless a lot of energy is expended slowing the material down, it will hit Venus at about 50km/s. The violence of the resulting atmospheric explosion will blast a lot of the hydrogen straight back into space as a plasma. This is exactly why comets have not delivered very much water to the moon. You would need one heck of a strong magnetic field to prevent the hydrogen escaping.

The idea of moving 1x10^21kg of water across the solar system from any source, still seems far fetched to me. We are talking a billion cubic kilometres of water here, that's a cube 1000km on a side. We are talking about moving a planet sized object. The amount of energy needed is just ridiculous. Every few tonnes of that material would require the energy equivelent of a small A-bomb to provide the required delta-V. And we are talking about moving a billion billion tonnes of water.

Tom Kalbfus · 2015-07-30 23:57:06

Antius wrote:

Tom Kalbfus wrote:
Antius wrote:
Ceres is much closer and would therefore be a much easier source of hydrogen than Pluto. It also has a relatively high rotation rate, meaning you can use its angular momentum to propel packages from a space elevator without the need for propellant. If a future colony governor is sitting on Venus trying to buy 1000 tonnes of hydrogen, you can bet he will buy it where it is cheapest. He won't be ordering it from Pluto just because it 'looks' more abundant.
Transporting materials from across the solar system will always be expensive and will only take place in relatively small amounts. It is most sensible to assume that Venus will remain hydrogen poor and look for solutions that allow you to work around it. Closed paraterraformed biospheres, recycling hydrogen with very high efficiency. Over geological timescales, enough hydrogen will leak from these structures to give Venus some modest reserve in the external environment.
The mass of the oceans is approximately 1.35×10^18 metric tons, or about 1/4400 of Earth's total mass. The oceans cover an area of 3.618×108 km2 with a mean depth of 3682 m, resulting in an estimated volume of 1.332×109 km3.[136] If all of Earth's crustal surface was at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km.[137][138]
https://en.wikipedia.org/wiki/Earth
Mass of Earth's Oceans is 1.35x10^21 kg
Mass of Pluto is 1.290x10^22 kg
If 10% of Pluto's mass is water ice, then I'd say Pluto has enough water.
One fifth of water's mass is hydrogen and that would be 270,000,000,000,000,000,000 kg of hydrogen which needs to be sent from Pluto to Venus to make an ocean equal to Earth's.
The Mass of Ceres is 9.393x10^20 kg, I'm sure not all of it is water.
The escape velocity is 0.51 km/sec
The average orbital speed is 17.9 km/sec. So to escape Cere's gravity and eliminate its forward orbital velocity you need a delta-v of around 18 k/sec compared with just 8 km/sec for Pluto and to give it an inward velocity of 2 km/sec to hit Venus in 95 years. Also it appears that Ceres has only one tenth of the mass of Earth's Oceans. So as you can see Pluto has some obvious advantages, there is the 95 year journey sunward, but terraforming Venus is going to take longer than that anyway, the first step would be shading the planet and letting it cool. While you are building the shade at L1, you might also be mining Pluto for water, separating out the hydrogen and dumping the Oxygen left behind on Pluto's surface. You see, just like Nitrogen, oxygen is a solid on Pluto's surface, you would have nitrogen and oxygen glaciers after that. The energy to deliver the hydrogen from Pluto would be less than that from Ceres.
There is just one problem with dumping oxygen on Pluto's surface. Oxygen is an oxidizer, you make a large enough pile of it on Pluto, it will possible react with Pluto's surface, which contains a lot of carbon compounds. Maybe the oxygen should be sent to Mars, maybe dump some of it on Earth's Moon as well. I suspect that this amount of oxygen is way more than Mars needs to make its atmosphere breathable, and may in fact be too much! We could give the Moon an temporary Oxygen atmosphere with all this excess oxygen, it will leak into space, but we can dump enough on the Moon so that it stays there for a while anyway.
Problem is that unless a lot of energy is expended slowing the material down, it will hit Venus at about 50km/s. The violence of the resulting atmospheric explosion will blast a lot of the hydrogen straight back into space as a plasma. This is exactly why comets have not delivered very much water to the moon. You would need one heck of a strong magnetic field to prevent the hydrogen escaping.

You are assuming a perfectly elastic collision between the hydrogen molecules and Venus's atmosphere. What is Venus's atmosphere but a fluid, when hydrogen molecules hit on Carbon-dioxide molecules, those later molecules impact energy of the hydrogen, other carbon-dioxide molecules block the path of hydrogen atoms heading back out toward space. The initial kinetic energy gets spread out among surrounding carbon-dioxide molecules in the atmosphere gets absorbed by the atmosphere rather than bouncing off of it as if it were a solid shell surrounding the planet.

The idea of moving 1x10^21kg of water across the solar system from any source, still seems far fetched to me. We are talking a billion cubic kilometres of water here, that's a cube 1000km on a side. We are talking about moving a planet sized object. The amount of energy needed is just ridiculous. Every few tonnes of that material would require the energy equivelent of a small A-bomb to provide the required delta-V. And we are talking about moving a billion billion tonnes of water.

Terraforming is not for the faint of heart.

Antius · 2015-07-31 05:45:44

Tom Kalbfus wrote:

You are assuming a perfectly elastic collision between the hydrogen molecules and Venus's atmosphere. What is Venus's atmosphere but a fluid, when hydrogen molecules hit on Carbon-dioxide molecules, those later molecules impact energy of the hydrogen, other carbon-dioxide molecules block the path of hydrogen atoms heading back out toward space. The initial kinetic energy gets spread out among surrounding carbon-dioxide molecules in the atmosphere gets absorbed by the atmosphere rather than bouncing off of it as if it were a solid shell surrounding the planet.
The idea of moving 1x10^21kg of water across the solar system from any source, still seems far fetched to me. We are talking a billion cubic kilometres of water here, that's a cube 1000km on a side. We are talking about moving a planet sized object. The amount of energy needed is just ridiculous. Every few tonnes of that material would require the energy equivelent of a small A-bomb to provide the required delta-V. And we are talking about moving a billion billion tonnes of water.
Terraforming is not for the faint of heart.

Or for those light in the pocket it would seem. A sun-shield would mass in the tens - hundreds of millions of tonnes. But that is achievable with space manufacturing. If the planet cools down rapidly enough to allow human colonisation on a timescale of a century or two, it is not an unattractive investment.

I wonder how much water remains in the Venusian interior? As human beings we do not need oceans of water to survive. Just enough to meet our physiological needs. I remember reading that the sulphuric acid in the atmosphere would provide enough water to cover the planet to a depth of an inch if it condensed onto the surface. Not enough for a planet-wide biosphere, but perhaps enough to support human settlements on a large scale if they recycle efficiently and do not expect swimming to become their national sport. Recycling would be easier to achieve in parraterraformed cities. These would initially appear to be neccesary anyhow, as even after much of the atmospheric CO2 liquefies, at least a few bar would remain in the atmosphere.

In three hundred years, Venus may resemble a parraterraformed version of Star Trek's Vulcan - A dry planet, with humans occupying compact self-sufficient cities.

RobertDyck · 2015-07-31 07:02:32

NASA Space Science Data Coordinated Archive (NSSDC) Venus Fact Sheet:

Venus Atmosphere
Surface pressure: 92 bars
Surface density: ~65. kg/m^3
Scale height: 15.9 km
Total mass of atmosphere: ~4.8 x 10^20 kg
Average temperature: 737 K (464 C)
Diurnal temperature range: ~0
Wind speeds: 0.3 to 1.0 m/s (surface)
Mean molecular weight: 43.45 g/mole
Atmospheric composition (near surface, by volume):
Major: 96.5% Carbon Dioxide (CO2), 3.5% Nitrogen (N2)
Minor (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20;
Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7

Calculating: 20 parts per million by volume water, total mass of atmosphere 4.8 x 10^20 kg
I could get into molecular weight of water vs CO2 to convert ppm volume into ppm mass, but these figures are only 2 significant figures anyway. So...
mass of water = 20 * (4.8 x 10^20 kg) / 10^6 = 96.0 x 10^14 kg = 9.6 x 10^15 kg
Is that right?

Tom Kalbfus · 2015-07-31 07:54:57

Antius wrote:

Tom Kalbfus wrote:
You are assuming a perfectly elastic collision between the hydrogen molecules and Venus's atmosphere. What is Venus's atmosphere but a fluid, when hydrogen molecules hit on Carbon-dioxide molecules, those later molecules impact energy of the hydrogen, other carbon-dioxide molecules block the path of hydrogen atoms heading back out toward space. The initial kinetic energy gets spread out among surrounding carbon-dioxide molecules in the atmosphere gets absorbed by the atmosphere rather than bouncing off of it as if it were a solid shell surrounding the planet.
The idea of moving 1x10^21kg of water across the solar system from any source, still seems far fetched to me. We are talking a billion cubic kilometres of water here, that's a cube 1000km on a side. We are talking about moving a planet sized object. The amount of energy needed is just ridiculous. Every few tonnes of that material would require the energy equivelent of a small A-bomb to provide the required delta-V. And we are talking about moving a billion billion tonnes of water.
Terraforming is not for the faint of heart.
Or for those light in the pocket it would seem. A sun-shield would mass in the tens - hundreds of millions of tonnes. But that is achievable with space manufacturing. If the planet cools down rapidly enough to allow human colonisation on a timescale of a century or two, it is not an unattractive investment.
I wonder how much water remains in the Venusian interior? As human beings we do not need oceans of water to survive. Just enough to meet our physiological needs. I remember reading that the sulphuric acid in the atmosphere would provide enough water to cover the planet to a depth of an inch if it condensed onto the surface. Not enough for a planet-wide biosphere, but perhaps enough to support human settlements on a large scale if they recycle efficiently and do not expect swimming to become their national sport. Recycling would be easier to achieve in parraterraformed cities. These would initially appear to be neccesary anyhow, as even after much of the atmospheric CO2 liquefies, at least a few bar would remain in the atmosphere.
In three hundred years, Venus may resemble a parraterraformed version of Star Trek's Vulcan - A dry planet, with humans occupying compact self-sufficient cities.

You need 70% water coverage to sustain an Earthlike environment. A desert world wouldn't be able to sustain an oxygen atmosphere.

Last edited by Tom Kalbfus (2015-07-31 07:58:44)

Antius · 2015-07-31 07:55:55

A few calculations.

Assumption 1: A future Venus is inhabited by 1 billion people. An initial stock of water was provided by decomposing the planet’s sulphuric acid, but hydrogen imports are needed to make up for losses;

Assumption 2: Venusian cities carefully recycle hydrogen, but lose 10% per year through biosphere leakage;

Assumption3: GDP per capita for future Venus is $50,000 with 5% of this being spent importing fresh hydrogen.

Question: With 10% annual losses, how much per capita water inventory can the average Venusian afford?

Assumption 4: Let’s say import cost is $100/kg

Answer: Inventory (per cap) = (0.05 x GDP/cap) / (0.01xannual loss % x 0.11 (% H2 in H2O) x Cost/kg

Inventory (per cap) = (0.05 x 50,000)/(0.01x10 x 0.11x100) = 2250kg-water/person

Realistically enough to produce food, day-to-day living and perhaps some reasonable city parks. Not enough to build global oceans at any realistic timescale.

Tom Kalbfus · 2015-07-31 08:05:06

Antius wrote:

A few calculations.
Assumption 1: A future Venus is inhabited by 1 billion people. An initial stock of water was provided by decomposing the planet’s sulphuric acid, but hydrogen imports are needed to make up for losses;
Assumption 2: Venusian cities carefully recycle hydrogen, but lose 10% per year through biosphere leakage;
Assumption3: GDP per capita for future Venus is $50,000 with 5% of this being spent importing fresh hydrogen.
Question: With 10% annual losses, how much per capita water inventory can the average Venusian afford?
Assumption 4: Let’s say import cost is $100/kg
Answer: Inventory (per cap) = (0.05 x GDP/cap) / (0.01xannual loss % x 0.11 (% H2 in H2O) x Cost/kg
Inventory (per cap) = (0.05 x 50,000)/(0.01x10 x 0.11x100) = 2250kg-water/person
Realistically enough to produce food, day-to-day living and perhaps some reasonable city parks. Not enough to build global oceans at any realistic timescale.

We could have settlements that float in the atmosphere already without terraforming. Just having domed settlements on the surface would not be sufficient justification for a massive Sun shield. If your going to modify a planet, you might as well modify it for maximum human habitability.

I think first we shade the planet and let it cool, this would take about a century anyway if the shield completely blocks the Sun. After it cools, have incoming hydrogen hit the atmosphere at a rate which keeps the atmosphere warm.

Tom Kalbfus · 2015-07-31 11:35:35

Tom Kalbfus wrote:

Antius wrote:
A few calculations.
Assumption 1: A future Venus is inhabited by 1 billion people. An initial stock of water was provided by decomposing the planet’s sulphuric acid, but hydrogen imports are needed to make up for losses;
Assumption 2: Venusian cities carefully recycle hydrogen, but lose 10% per year through biosphere leakage;
Assumption3: GDP per capita for future Venus is $50,000 with 5% of this being spent importing fresh hydrogen.
Question: With 10% annual losses, how much per capita water inventory can the average Venusian afford?
Assumption 4: Let’s say import cost is $100/kg
Answer: Inventory (per cap) = (0.05 x GDP/cap) / (0.01xannual loss % x 0.11 (% H2 in H2O) x Cost/kg
Inventory (per cap) = (0.05 x 50,000)/(0.01x10 x 0.11x100) = 2250kg-water/person
Realistically enough to produce food, day-to-day living and perhaps some reasonable city parks. Not enough to build global oceans at any realistic timescale.
We could have settlements that float in the atmosphere already without terraforming. Just having domed settlements on the surface would not be sufficient justification for a massive Sun shield. If your going to modify a planet, you might as well modify it for maximum human habitability.
I think first we shade the planet and let it cool, this would take about a century anyway if the shield completely blocks the Sun. After it cools, have incoming hydrogen hit the atmosphere at a rate which keeps the atmosphere warm.

I've had some virus issues with my Computer, I'm typing from a library Computer, all the constant popups and virus warnings on my computer have made it difficult for me to respond on my computer.

I think if we are going to terraform Venus, we might as well make it into another Earth. Moving the hydrogen depends on utilizing nonhuman labor, basically self-reproducing robots and computers, if we can get enough of those build, then moving the necessary hydrogen from Pluto is just a matter of those robots replicating another of times, mining the crust of Pluto for hydrogen, seperating the hydrogen out of the compounds. I think the oxygen doesn't necessarily have to be exported, it could for instance be combined with the carbon in methane to produce carbon dioxide (which will form dry ice on the surface of pluto), we would thus liberate the hydrogen from both the methane and the water molecules, we would want to seperate out the deuterium we would also liberate so we could power our fusion reactors which would power the process, the plain old protonic hydrogen we would send to Venus to make 5 times its weight in Water, we would then reverse the reaction, that we did on pluto, spiting the carbon dioxide to liberate the oxygen, combine it with imported Plutonian hydrogen to make water and release it into the atmosphere. I think hydrogen could be obtained more easily from Pluto than any of the four gas giants.

Spatula · 2015-11-09 11:44:21

Making it into another earth would be nice if it were possible, but according to our more recent atmospheric models, Venus may simply lie too close to the sun to retain large oceans without having them boil off at the equator and causing a runaway greenhouse. These models could be deficient of course (and I believe they are... pretty sure early earth should've had a runaway greenhouse too under such models since it had a vastly thicker atmosphere with 20% CO2, yet it's supposedly just 5% within the habitable zone... I am a bit skeptical of all of that). Nevertheless, it could be that Venus is too close to be sustainable as a wet planet without some kind of massive solar shield protecting it at all times.

It does fit well within the arid habitable zone under our models though. If H2O in the atmosphere were kept around 1%, and the planet were converted into a dune-like desert planet, it could sustain livable temperatures without any solar shield, and it would be economically useful to us in that form anyway.

Void · 2015-11-09 15:28:53

Hi Spatula, nice to think another planet could inspire the minds of space enthusiasts. Also, I am making sure your post (Which is before this one), does not go unnoticed.

Last edited by Void (2015-11-09 15:29:15)

SpaceNut · 2015-11-24 20:38:35

The chances of boil off can be stopped by active cooling and by blocking the suns intensity that hits the surface but to get that far along we will need to first get a foot hold in the clouds and start to create the new world that we want via teraforming....

Tom Kalbfus · 2015-12-02 12:33:50

SpaceNut wrote:

The chances of boil off can be stopped by active cooling and by blocking the suns intensity that hits the surface but to get that far along we will need to first get a foot hold in the clouds and start to create the new world that we want via teraforming....

How about we give Venus, "Ring around the Planet?" A broad ring around Venus' equator may cool the planet enough. Venus has practically no tilt, so a Venusian ring may be a practical thing to build!

SpaceNut · 2015-12-02 21:23:38

From calculating the wattage from earth orbit at 1360 and estimating that level at venus distance that would make it 1680 but the real level is 2500 that said we are looking trying to reduce the real value by 35 %. Since venus has a diameter of 12,100 km we need to cover an area that would be 4235 km at a stationary orbit to lower the temperature of the atmosphere.

http://courseweb.glendale.edu/ppal/Word … 20Mars.pdf

http://sci.esa.int/venus-express/34067-venus-vs-earth/

Antius · 2015-12-03 11:12:08

RobertDyck wrote:

NASA Space Science Data Coordinated Archive (NSSDC) Venus Fact Sheet:
Venus Atmosphere
Surface pressure: 92 bars
Surface density: ~65. kg/m^3
Scale height: 15.9 km
Total mass of atmosphere: ~4.8 x 10^20 kg
Average temperature: 737 K (464 C)
Diurnal temperature range: ~0
Wind speeds: 0.3 to 1.0 m/s (surface)
Mean molecular weight: 43.45 g/mole
Atmospheric composition (near surface, by volume):
Major: 96.5% Carbon Dioxide (CO2), 3.5% Nitrogen (N2)
Minor (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20;
Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7
Calculating: 20 parts per million by volume water, total mass of atmosphere 4.8 x 10^20 kg
I could get into molecular weight of water vs CO2 to convert ppm volume into ppm mass, but these figures are only 2 significant figures anyway. So...
mass of water = 20 * (4.8 x 10^20 kg) / 10^6 = 96.0 x 10^14 kg = 9.6 x 10^15 kg
Is that right?

1x10^16 kg of water on Venus works out to be 21.74kg/m2. That's a depth equivelant of 2.2cm. So that sounds about right.

If the atmosphere could be gradually reduced to 1 bar with a column density of 11tonnes/m2, then H20 mass concentration in air would be 0.2%. By volume, assuming a molar mass of 29 for air, that would 0.32%, probably closer to 0.5% beneath the solidus line. A terraformed Venus would probably have clouds and maybe an occasional pond. No oceans or seas.

Tom Kalbfus · 2015-12-03 11:29:28

SpaceNut wrote:

From calculating the wattage from earth orbit at 1360 and estimating that level at venus distance that would make it 1680 but the real level is 2500 that said we are looking trying to reduce the real value by 35 %. Since venus has a diameter of 12,100 km we need to cover an area that would be 4235 km at a stationary orbit to lower the temperature of the atmosphere.
http://courseweb.glendale.edu/ppal/Word … 20Mars.pdf
http://sci.esa.int/venus-express/34067-venus-vs-earth/

I don't think a stationary orbit actually exists for Venus, that would be an orbit that is stationary relative to Venus' surface, as it has a very slow rotation rate. I think we would want the orbits to be as close to the surface as structurally possible to minimize the amount of construction material needed, a low Venus orbit might be preferable. We need very tall objects orbiting over the equator, their lengths would have to be perpendicular to plane of the orbit, it would be best described as an orbiting wall. The center of mass of the wall would be within the orbital plane, while half the mass would be above it and half below. Fortunately in orbit, gravity is minimal. Since this wall would be orbiting above the equator, half of it would be to the north and the other half to the south. Portions of the wall that were north of the equator would experience net gravitational force pulling towards the ring plane, portions to the south would feel gravity pulling towards the North, and the gravity fields north and south of the orbital plane are not completely canceled by orbital motion. the futher north and south of the orbital plane, the more gravity is felt up to the maximum gravitational pull of the planet at that distance subject to the inverse square law with distance. I think there is a limit to how tall the wall can be without crumbling under its own weight. the advantage is, the further out you build your encircling wall the less the wall is subject to these gravitational forces. These forces would be significantly less than that felt by an equally high wall on the surface of the Earth.

Last edited by Tom Kalbfus (2015-12-03 11:30:36)

Antius · 2015-12-03 11:39:22

SpaceNut wrote:

From calculating the wattage from earth orbit at 1360 and estimating that level at venus distance that would make it 1680 but the real level is 2500 that said we are looking trying to reduce the real value by 35 %. Since venus has a diameter of 12,100 km we need to cover an area that would be 4235 km at a stationary orbit to lower the temperature of the atmosphere.
http://courseweb.glendale.edu/ppal/Word … 20Mars.pdf
http://sci.esa.int/venus-express/34067-venus-vs-earth/

You would need to cool the planet to at least -50C in order to dispose of its crushing atmosphere. Once that is done, the CO2 would self-sequester. It would first liquefy on the surface. As the crust cooled, enormous fissures would open and liquid CO2 would seep into the crust leaving a dry surface behind. At some point, enough of the CO2 will have been trapped as carbonates to allow temperature to be brought up again. To bring venusian temperatures down to martian levels, would require at least 2/3rds of light arriving on the planet be blocked before it reaches the atmosphere.

A ring sun shield would waste a lot of material because only the section of the ring between the planet and the sun at that time would block sunlight. A cheaper solution would be a spherical shield interior to the orbit of Venus maintaining the same orbital speed. Sunlight pressure could then be balanced against the sun's gravity and used to maintain position of the shield w.r.t Venus. A spherical shield 10,000km in diameter would be sufficient. If made from 0.01mm aluminium, it would weigh 3 billion tonnes.

Tom Kalbfus · 2015-12-03 11:59:38

Antius wrote:

RobertDyck wrote:
NASA Space Science Data Coordinated Archive (NSSDC) Venus Fact Sheet:
Venus Atmosphere
Surface pressure: 92 bars
Surface density: ~65. kg/m^3
Scale height: 15.9 km
Total mass of atmosphere: ~4.8 x 10^20 kg
Average temperature: 737 K (464 C)
Diurnal temperature range: ~0
Wind speeds: 0.3 to 1.0 m/s (surface)
Mean molecular weight: 43.45 g/mole
Atmospheric composition (near surface, by volume):
Major: 96.5% Carbon Dioxide (CO2), 3.5% Nitrogen (N2)
Minor (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20;
Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7
Calculating: 20 parts per million by volume water, total mass of atmosphere 4.8 x 10^20 kg
I could get into molecular weight of water vs CO2 to convert ppm volume into ppm mass, but these figures are only 2 significant figures anyway. So...
mass of water = 20 * (4.8 x 10^20 kg) / 10^6 = 96.0 x 10^14 kg = 9.6 x 10^15 kg
Is that right?
1x10^16 kg of water on Venus works out to be 21.74kg/m2. That's a depth equivelant of 2.2cm. So that sounds about right.
If the atmosphere could be gradually reduced to 1 bar with a column density of 11tonnes/m2, then H20 mass concentration in air would be 0.2%. By volume, assuming a molar mass of 29 for air, that would 0.32%, probably closer to 0.5% beneath the solidus line. A terraformed Venus would probably have clouds and maybe an occasional pond. No oceans or seas.

So there are ten trillion metric tons of water in Venus' atmosphere. Aren't there a number of objects in the Solar System that contain more water than that?

How about
PASIPHAE
Pasiphae is Jupiter's fifteenth moon. Pasiphae is 22 miles (36 km) in diameter and orbits 14,600,000 miles (23,500,000 km) from Jupiter. Pasiphae has a mass of 2 x 1023kg. It orbits Jupiter in 735 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). Very little is known about Pasiphae. Pasiphae was discovered by P. Melotte in 1908.
http://www.enchantedlearning.com/subjec … oons.shtml

So Pasiphae has a mass of 200,000,000,000,000,000,000,000 kg or 200 Sextillion kilograms. What do you think are the possibilities of dislodging this moon from its orbit and sending it hurtling towards Venus? I'll bet a significant portion of it is water, and we have Jupiter and its satellites to use as a gravitational assist. An encounter with Callisto can send it hurtling towards Jupiter, at the closest point to Jupiter, (maybe tidal forces will tear it apart), and a number of pieces will come hurtling towards Venus impacting on its surface. What a planetary disaster this would be!

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