Colonizing other planets

[peadar1987]

4 hours ago, todofwar said:

Watney would have probably died a few weeks in (radiation).

Common misconception, but totally untrue. Annual dose, unshielded, on the surface of Mars is about 240mSv, as measured by Curiosity. 100mSv is the lowest dose statistically linked to any increased cancer risk. You need to absorb about 5Sv in one go to have a 50% chance of dying of radiation sickness without medical treatment.

In reality, the hab, rovers and spacesuit would have blocked a proportion of the radiation. Watney would have a significantly higher chance of developing cancer later in life due to the extra radiation he will have absorbed during his 500+ Sol stay on Mars, but radiation sickness would not even be on the radar unless the RTG ruptured.

[AngelLestat]

On 2/4/2016 at 0:26 PM, RocketSquid said:

@AngelLestat, @fredinno

Please make sure you keep these things civil. The best way to settle this would probably be with a pros/cons list for Venus colonies.

I don't have any trouble to explain, provide evidence and prove points over and over, but in the cases I prove my points, is so much to ask for bit of recognition?   In fact, I know that he changes his mind many times, because I see him correcting others using the knowledge of our past discussion, in which I did not receive any recognition in those times either. I always thanks for any new info that I did not know or when someone proves me wrong.

On 3/4/2016 at 8:22 PM, todofwar said:

Not sure if this has been mentioned, .....

In a floating Venus colony you get access to so many different types of energy, from geothermal like pipes you can drop to harness the temperature gradient, to hanging wind turbines to harness the wind gradient. In fact, since any kind of pipe designed to harness the thermal gradient would need to be quite long (nothing compared to some things we've already built here on earth) you can slap a few turbines on it to do both. What does Mars have?

Maybe not in this topic
Welcome to the forum. About mars you can use nuclear energy in the poles if you extreme your precaution measures, but is not easy to transport that energy to different mining places or locations of interest, so depending your latitude you need to choose between nuclear or solar.

21 hours ago, fredinno said:

Mining from Venus Surface is not impossible, but expensive. Couple that with lack of hydrogen, and high gravity well (even from the atmosphere), and you have a very uneconomical place to build a colony.

Why you dont provide a reason explaining why it will be expensive taking into account all the things that I already explain?
You have A LOT more minerals in venus surface than on earth, without the need to even dig, is all in the surface.  Again, you don't need to export to get profit, and rare elements can be exported at very cheap cost vs earth.

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Also, if there was a movie "The Venusian", Mark Watney would be hit by the airlock, and fall to his death onto the planet below

Why?  in the movie matt damon was with its spacesuit inside his habitat (something very weird), in that rare case why he can not have a inflatable balloon on his back too or just a rope?

9 hours ago, Nibb31 said:

We have experience soft-landing on hard surfaces since Mars 3 in 1971, then Viking 1 and 2. There have also been Phoenix and MSL, and in the future Insight (if it ever flies) and Schiaparelli (the Exomars lander).

We also have experience soft-landing on the Moon, and on Earth. There is no reason why we couldn't soft-land a larger vehicle.

On the other hand, deploying sustaining balloons from a hypersonic reentry vehicle isn't something that we any experience with.

Some mars mission crash even after those successful landings or if you prefer called after all that "experience collected".
When they land the curiosity, you can see that they all had diapers to stand the nerves of that moment. If is so easy to realize a propulsion landing why spacex fails so often?
There is a big reason why we can not land a larger vehicle, is due volume, surface and mass relation. The atmosphere of mars is not enough to brake a bigger payload that for sure it will have a low shielding surface for its big mass.
So you should use many different alternatives together, like supersonic retropropulsion with special inflatable shielding or aerodynamics and ISRU to get the fuel on mars so you save to carry the fuel to mars departure.
All this was explained in many sites or in the official NASA documentary about the travel to mars (netflix).

On the other hand, float in venus is not more complex than open your first inflatable shield in mars removing the previous step of supersonic retropropulsion, about experience..  venus atmosphere from 52km to the upper top is analog to the earth atmosphere.

9 hours ago, todofwar said:

An airlaunch is tricky, but there is a reason Virgin is working on it

And the air force.

Launching from 50 km is not tricky, is even safer.  If your rocket fall does not crash, you have plenty of time to eject the capsule and float back to your airship base.
You dont have much issues with noise vibrations.  Launching horizontal or vertical does not have much difference.

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And of course there is no economic benefit to colonizing any planet, though there may be an ecological argument to strip mine asteroids and planets so as to preserve the environment on Earth (bringing fuel back from Titan would be a terrible terrible idea though). So Venus would have to be a charity mission, a concentrated effort to allow our species a second chance should this planet get wiped out. But the same can be said for just about everywhere.  

I believe it is, but people should forget about instant payoff or the first missions being 100% profit motivated..  no..
There is also one magic concept that nobody here takes into account..  "local economies". 
 

5 hours ago, fredinno said:

Mars is about the 33% barrier that is thought to be the point where low gravity is not a huge problem. This is just an educated guess by scientists, though, we don't have any art. G modules on the ISS that would be necessary to do research (it was cancelled )

You have a link of one scientist making that educated guess?  

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It's orbit (around Deimos) is great- it's a constant, stable location that also offers opportunities to study Mars.

Why you want be around deimos??  what is the benefit of that?   We did not study mars from above enough already?

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You can't "easily land" in the upper atmosphere. The hazy atmosphere also blocks out a lot of sunlight, so you'll be getting less light than you would expect.

He did not mention what he expect, but you still get more than earth just using solar, wind is even more cost effective and constant.

4 hours ago, peadar1987 said:

Common misconception, but totally untrue. Annual dose, unshielded, on the surface of Mars is about 240mSv, as measured by Curiosity. 100mSv is the lowest dose statistically linked to any increased cancer risk. You need to absorb about 5Sv in one go to have a 50% chance of dying of radiation sickness without medical treatment.

In reality, the hab, rovers and spacesuit would have blocked a proportion of the radiation. Watney would have a significantly higher chance of developing cancer later in life due to the extra radiation he will have absorbed during his 500+ Sol stay on Mars, but radiation sickness would not even be on the radar unless the RTG ruptured.

He clearly mistake in those values, but your values like 5sv = 50% does not have much support either.
We dont know the long term effect of radiation, but we clearly know that permanent stay on mars under 240 msv is bad.  So you should find a way to reduce those issues if you plan to stay there a considerable time.

Edited April 4, 2016 by AngelLestat

[fredinno]

17 minutes ago, AngelLestat said:

Why?  in the movie matt damon was with its spacesuit inside his habitat (something very weird), in that rare case why he can not have a inflatable balloon on his back too or just a rope?

Why would you carry an inflatable balloon? Even on the ISS, astronauts don't carry propulsive EVA suits, like in KSP. And you would need a grappling rope, which may or may not latch on properly.

17 minutes ago, AngelLestat said:

Quote

 

Why you want be around deimos??  what is the benefit of that?   We did not study mars from above enough already?

You can also study Deimos

[peadar1987]

8 hours ago, AngelLestat said:

 

He clearly mistake in those values, but your values like 5sv = 50% does not have much support either.
We dont know the long term effect of radiation, but we clearly know that permanent stay on mars under 240 msv is bad.  So you should find a way to reduce those issues if you plan to stay there a considerable time.

Yes it does. The acute effects of radiation are extremely well-known. 5Sv all in one go will most likely kill you (I misremembered the 50% fatality dose, it's actually more like 4Sv).

The long-term effects of radiation are also pretty well known. We've got a very large sample size to work with. People involved in the nuclear industry, the Chernobyl accident, Hiroshima and Nagasaki, nuclear testing, and a whole load of unfortunate people who were deliberately and unethically exposed to radiation. Doses below about 100mSv, either instantaneously or over a period of time, probably cause a small increase in cancer risk, but the increase is too small to separate out from the background noise in the data, caused by things like genetics, diet, amount of exercise, and pure random chance. Above that, there's a pretty clear correlation between radiation dose and cancer risk, with the chance of developing cancer at some point in life increasing by 5.5% per Sievert absorbed. (https://en.wikipedia.org/wiki/Sievert)

240mSv will represent an increase in cancer risk of about 1.5%. To put that in perspective, a moderate smoking habit is linked to about an 8% increase in chance of developing lung cancer.

[todofwar]

Still hold that Mars is just a more difficult version of the Moon, with no real benefits aside from being able to say we have a Mars colony. And the whole landing issue will severely limit the initial growth. Sure, you can hit the self sustaining mark, but the self perpetuating mark will require a critical mass of mining, refining, and manufacturing equipment that will all have to be delivered from Earth. 

[fredinno]

9 hours ago, peadar1987 said:

Yes it does. The acute effects of radiation are extremely well-known. 5Sv all in one go will most likely kill you (I misremembered the 50% fatality dose, it's actually more like 4Sv).

The long-term effects of radiation are also pretty well known. We've got a very large sample size to work with. People involved in the nuclear industry, the Chernobyl accident, Hiroshima and Nagasaki, nuclear testing, and a whole load of unfortunate people who were deliberately and unethically exposed to radiation. Doses below about 100mSv, either instantaneously or over a period of time, probably cause a small increase in cancer risk, but the increase is too small to separate out from the background noise in the data, caused by things like genetics, diet, amount of exercise, and pure random chance. Above that, there's a pretty clear correlation between radiation dose and cancer risk, with the chance of developing cancer at some point in life increasing by 5.5% per Sievert absorbed. (https://en.wikipedia.org/wiki/Sievert)

240mSv will represent an increase in cancer risk of about 1.5%. To put that in perspective, a moderate smoking habit is linked to about an 8% increase in chance of developing lung cancer.

We don't know the effects of radiation + Zero-G, which is one reason we need a lunar orbital space station- however, we know that it probably isn't better than just radiation.

5 hours ago, todofwar said:

Still hold that Mars is just a more difficult version of the Moon, with no real benefits aside from being able to say we have a Mars colony. And the whole landing issue will severely limit the initial growth. Sure, you can hit the self sustaining mark, but the self perpetuating mark will require a critical mass of mining, refining, and manufacturing equipment that will all have to be delivered from Earth. 

Mars is easier in some way, it is far more earth-like, and has volatiles like Carbon the Moon lacks, along with far more water (and also nitrogen in the atmosphere). It's also a lot more scientifically useful to build a Mars Surface base than Venus Cloud or Moon base, due to its atmosphere, and water flows.

http://www.popsci.com/article/technology/crops-grow-fake-moon-and-mars-soil

Also, Lunar soil is far worse to grow crops than Mars soil, which plants can do pretty well on (with nitrogen fixation).

Edited April 5, 2016 by fredinno

[RocketSquid]

On 4/4/2016 at 10:52 AM, Nibb31 said:

We also have experience soft-landing on the Moon, and on Earth. There is no reason why we couldn't soft-land a larger vehicle.

On the other hand, deploying sustaining balloons from a hypersonic reentry vehicle isn't something that we any experience with.

*COUGH FUEL COSTS COUGH*

Why would you deploy balloons while still hypersonic? Balloons, or airbags if you prefer, come after the parachute.

https://en.wikipedia.org/wiki/Mars_Exploration_Rover#Airbags

8 hours ago, todofwar said:

Still hold that Mars is just a more difficult version of the Moon, with no real benefits aside from being able to say we have a Mars colony. And the whole landing issue will severely limit the initial growth. Sure, you can hit the self sustaining mark, but the self perpetuating mark will require a critical mass of mining, refining, and manufacturing equipment that will all have to be delivered from Earth. 

Two words reactions: Sabatier and Reverse Water Gas Shift.

Sabatier: CO₂ + 4 H₂ →  CH₄ + 2 H₂O

RWGS: CO₂ + H₂  → CO + H₂0

Combined, assuming the water output is electrolyzed: 2 H₂ + 3 CO₂ → CH₄ + 2 O₂ + 2 CO

These can both function in the same chamber. The combined reaction produces the exact correct ratio for combustion. Additionally, the carbon monoxide waste product can be used to make ethylene, and to smelt hematite (AKA mars dust) into iron (AKA awesomeness).

Also, mars has water, which also means oxygen and hydrogen, and it has a primarily CO₂ atmosphere, which means we can make oxygen.

[todofwar]

41 minutes ago, RocketSquid said:

*COUGH FUEL COSTS COUGH*

Why would you deploy balloons while still hypersonic? Balloons, or airbags if you prefer, come after the parachute.

https://en.wikipedia.org/wiki/Mars_Exploration_Rover#Airbags

Two words reactions: Sabatier and Reverse Water Gas Shift.

Sabatier: CO₂ + 4 H₂ →  CH₄ + 2 H₂O

RWGS: CO₂ + H₂  → CO + H₂0

Combined, assuming the water output is electrolyzed: 2 H₂ + 3 CO₂ → CH₄ + 2 O₂ + 2 CO

These can both function in the same chamber. The combined reaction produces the exact correct ratio for combustion. Additionally, the carbon monoxide waste product can be used to make ethylene, and to smelt hematite (AKA mars dust) into iron (AKA awesomeness).

Also, mars has water, which also means oxygen and hydrogen, and it has a primarily CO₂ atmosphere, which means we can make oxygen.

But combustion gives us so much energy because it is the energetically favored reaction. You need to drive the reverse somehow, which gets back to the energy problem. You have plenty of silicon for some solar cells sure, but that's all you have available. And you will need allot of solar panels to run the life support systems without getting into fuel production. 

Mars is not impossible, but Venus just seems more in reach to me. I think people might be seriously underestimating the amount of material we need to land on Mars (or any other planet we try to settle) before it hits that self sustaining mark. And then even more material, probably more than double, before you get self perpetuating (by which I mean the colony can grow without any further supply runs from Earth). The Moon will never be self perpetuating but it's so close to Earth that it becomes less of an issue overall. 

4 hours ago, fredinno said:

It's also a lot more scientifically useful to build a Mars Surface base than Venus Cloud or Moon base, due to its atmosphere, and water flows.

 

Actually, I would argue we kind of know why Mars failed, it's too small. You got a thin atmosphere, the volcanism was short lived even if it did give us some epic volcanoes, and no magnetic field. Venus, being so much more similar to Earth in terms of where it formed, can tell us much more about why Earth developed to support life and other planets might not. I also think we might be arguing about different things, I'm talking about a colony that will grow itself with no further Earth support, not a base to conduct experiments from.

[RocketSquid]

21 minutes ago, todofwar said:

But combustion gives us so much energy because it is the energetically favored reaction. You need to drive the reverse somehow, which gets back to the energy problem. You have plenty of silicon for some solar cells sure, but that's all you have available. And you will need allot of solar panels to run the life support systems without getting into fuel production.

Combustion isn't for power, you have nuclear or geothermal for that. Combustion is for launching things.

[fredinno]

1 hour ago, RocketSquid said:

Why would you deploy balloons while still hypersonic? Balloons, or airbags if you prefer, come after the parachute.

http://www.space.com/29141-venus-airship-havoc-nasa-concept-gallery.html

It looks the balloon would have to still deploy while hypersonic, the chute may not slow it enough before it goes too low in the atmosphere. I could be wrong, but deploying an airship from a heat shield in short order at subsonic speeds isn't easy either.

38 minutes ago, todofwar said:

But combustion gives us so much energy because it is the energetically favored reaction. You need to drive the reverse somehow, which gets back to the energy problem. You have plenty of silicon for some solar cells sure, but that's all you have available. And you will need allot of solar panels to run the life support systems without getting into fuel production. 

You want to use ISRU to produce rocket fuel, not combust for energy!

38 minutes ago, todofwar said:

Mars is not impossible, but Venus just seems more in reach to me. I think people might be seriously underestimating the amount of material we need to land on Mars (or any other planet we try to settle) before it hits that self sustaining mark. And then even more material, probably more than double, before you get self perpetuating (by which I mean the colony can grow without any further supply runs from Earth). The Moon will never be self perpetuating but it's so close to Earth that it becomes less of an issue overall. 

Yeah, and Venus is worse, it lacks metals (except at the surface, which can be mined with aerostats, but at great expense) and has low amounts of H2 (most of it locked in Sulfuric acid)

38 minutes ago, todofwar said:

Actually, I would argue we kind of know why Mars failed, it's too small. You got a thin atmosphere, the volcanism was short lived even if it did give us some epic volcanoes, and no magnetic field. Venus, being so much more similar to Earth in terms of where it formed, can tell us much more about why Earth developed to support life and other planets might not.

Yeah. We also know why Venus died, it was too close to the Sun, and was an aqua planet (like Earth), and since water vapor is a GHG, it warmed up and died way before the present day.

Also, Mars' past is easy to uncover, it's locked in the ground. Venus' high temperatures probably destroyed a good amount of the evidence of past life and conditions (and it's a lot harder to build a rover for Venus surface anyways). Mars is the best, for now.

Also, Mars is in the habitable zone. Venus is not. Yes, the 'zone moved outwards over time, but it's arguable that Mars had more Earth-like conditions. It's thought that Venus was already a (habitable) desert planet 1 Billion years ago.

38 minutes ago, todofwar said:

I also think we might be arguing about different things, I'm talking about a colony that will grow itself with no further Earth support, not a base to conduct experiments from.

I am talking about overall usefulness. You don't even have soil to grow stuff on Venus Atm.

Edited April 5, 2016 by fredinno

[RocketSquid]

1 minute ago, fredinno said:

It looks the balloon would have to still deploy while hypersonic, the chute may not slow it enough before it goes too low in the atmosphere. I could be wrong, but deploying an airship from a heat shield in short order at subsonic speeds isn't easy either.

I was talking for lithobraking on mars, which is what I assumed the person who had originally posted was talking about, as he mentioned "bouncing around toy cars on mars"

[fredinno]

Just now, RocketSquid said:

I was talking for lithobraking on mars, which is what I assumed the person who had originally posted was talking about, as he mentioned "bouncing around toy cars on mars"

Ah.

[AngelLestat]

13 hours ago, peadar1987 said:

Yes it does. The acute effects of radiation are extremely well-known. 5Sv all in one go will most likely kill you (I misremembered the 50% fatality dose, it's actually more like 4Sv).

The long-term effects of radiation are also pretty well known. We've got a very large sample size to work with. People involved in the nuclear industry, the Chernobyl accident, Hiroshima and Nagasaki, nuclear testing, and a whole load of unfortunate people who were deliberately and unethically exposed to radiation. Doses below about 100mSv, either instantaneously or over a period of time, probably cause a small increase in cancer risk, but the increase is too small to separate out from the background noise in the data, caused by things like genetics, diet, amount of exercise, and pure random chance. Above that, there's a pretty clear correlation between radiation dose and cancer risk, with the chance of developing cancer at some point in life increasing by 5.5% per Sievert absorbed. (https://en.wikipedia.org/wiki/Sievert)

240mSv will represent an increase in cancer risk of about 1.5%. To put that in perspective, a moderate smoking habit is linked to about an 8% increase in chance of developing lung cancer.

But you are only counting fatal cases, radiation effects goes beyond that, you have a Deterministic effects and Stochastic effects, the seconds happens at random with random effects.
Most of those effects can not be related or detected, it can change your adn in a way you pass a fatal or nonfatal error to your children or grandchildren, or it can affect your health in many different ways.
Chernobyl, Hiroshima and Nagasaki happen in places where the documentation could be hidden or was not done too seriously.  Then you need a big team trying to recover all those documents with different symptoms and  death circumstances, in which most of the doctors instead put the real possible cause they just note the obvious "heart stroke". (my dad as evidence who die from cancer).
What are the effects of radiation in pregnant women?  Or even in sperm?  How a baby develops under those radiation levels?  You will be calm if it was your baby the one that is growing under 240sv his/her whole life?
What about solar flares?  Earth and Venus had a big shield mass against those, on mars surface is similar than open space.
The issue is clear, and if you want to have a permanent colony in mars, you need to at least guarantee that your habitants will not get more than 20 sv by year.
Any other value or the posture of said "radiation is not a problem" is not serious enough (and you know that)  

4 hours ago, fredinno said:

Mars is easier in some way, it is far more earth-like, and has volatiles like Carbon the Moon lacks, along with far more water (and also nitrogen in the atmosphere). It's also a lot more scientifically useful to build a Mars Surface base than Venus Cloud or Moon base, due to its atmosphere, and water flows.

Venus is more earth-like, pressure, temperature, gravity, sun radiance, sounds, thermal conduction, etc.  The only that mars has similar to earth is that surface picture, but when you are there you will notice fast with your other senses that is nothing alike earth, here you are looking mars just with your eyes.

Why it is more scientifically useful?  In venus you can improve our climate models to understand with precision what would happen with the climate change here on earth and the best way to stop it.  You can study the ground and its big atmosphere with almost no resources, because the floating habitat can be in any place of the planet without any trouble with transport.  

4 hours ago, fredinno said:

http://www.popsci.com/article/technology/crops-grow-fake-moon-and-mars-soil

Also, Lunar soil is far worse to grow crops than Mars soil, which plants can do pretty well on (with nitrogen fixation).

Today most of the crops does not really need soils, you can have vertical farms (which are many times more cost efficient than normal farming) using led light and in many cases no soil at all, just inserting all the nutrients using the same water.

9 minutes ago, fredinno said:

It looks the balloon would have to still deploy while hypersonic, the chute may not slow it enough before it goes too low in the atmosphere. I could be wrong, but deploying an airship from a heat shield in short order at subsonic speeds isn't easy either.

No, the deployment happens at low speeds, that is why you have a parachute..  and you have plenty of time to open.

9 minutes ago, fredinno said:

Yeah, and Venus is worse, it lacks metals (except at the surface, which can be mined with aerostats, but at great expense) and has low amounts of H2 (most of it locked in Sulfuric acid)

Mars does not have much water at low latitudes neither, the mining in venus would be more cheap than mars for sure.
1-venus has more heavy elements than mars
2-you can use venus temperatures to reduce the amount of energy to shape metals, in the aluminum case you will have to rise the temperature only 200 degrees, for other metals ther energy save is not much, but it helps.
3-very easy to collect those metals for any kind of floating habitat, because these habitats can be in any place they want over the planet without spending almost no energy, in mars you need infrastructure or special vehicles wasting a lot of minerals to transport those minerals to any location of need.
4-You get a lot more energy in venus, and you need energy to mine, on mars you need to use solar panels at very low efficiency storing the energy for night.
5-sulphuric acid is the chemical substance more used in industry, is perfect to separate metals in mining or many other uses, more if you use it under pressure at high temperature, they become much more effective.

9 minutes ago, fredinno said:

Yeah. We also know why Venus died, it was too close to the Sun, and was an aqua planet (like Earth), and since water vapor is a GHG, it warmed up and died way before the present day.

Is still there, I saw it!
Why it matters?  venus is perfect the way it is, it provides different environments and characteristics to reduce the cost of some manufacturers. Also if you are thinking in terraform mars.. haha, that is not practical at all. 

[insert_name]

@AngelLestatdon't tell me that climate change will turn earth into venus. all that carbon was in the air at one point, and earth wasn't like venus, just a little hotter. also what industry in their right mind would go to venus? Also venus has significantly higher tempatures and pressures than earth, whereas mars's surface can get into earthlike temps during the day, and is closer to earths atmospheric pressure. also venus's day is over 200 earth days, making a lunar day look easy. also don't tell me that building a base in a cloud of sulfuric acid is a good idea.

[AngelLestat]

@insert_name No, I am not saying that.. I said to improve our climate model..

A climate model should predict and work fine in any atmosphere, like mars, venus, earth or titan.
What is a climate model?   just a mathematical model that we were adjusting and tunning using known physics and comparing the model and seeing what parameters or calculations gives the most accurate predictions.
So you make a prediction, you set all the variables and you find if the prediction match with the reality.
So if does not match, you try to corrected until it match, but earth atmosphere is just 1 case for that math model..  you need different variables in different enviroments to test your math model.

Is like try to find the correct equation of a function just knowing all the values that the function has over a small range, so you dont know if the function grows or decrease beyond those values.
So venus atmosphere is the holy grail for climate scientist, because they can test their climate models in a very different environment and compare the predictions with the real conditions.
When they match the venus predictions keeping, then the earth predictions will improve because you are more close to the real math model to describe atmospheres.    

[todofwar]

Sulfuric acid is not as bad as you think, actually. It's one of the most produced chemicals on Earth, and not that we would take any from Venus to Earth but it's a good resource for a growing civilization to have access to. And at 50 km above the surface temps are Earth temps and pressure is Earth pressure, Mars is practically a vacuum.  

As for the comment on soil, it's not a big deal. Chemically speaking you have access to most of the elements you need in the atmosphere, and you would want to grow using lightweight hydroponics anyway.

Sort of seperate from this but I am always curious why people were quick to speculate about life on Titan, a place so cold you have methane seas, and write off Venus. Whose to say there couldn't be exotic life forms using supercritical CO2 as a medium? From a kinetic perspective, any chemistry happening on Titan is painfully slow. Venus at least can have some things going at a decent pace. 

[fredinno]

59 minutes ago, todofwar said:

Sulfuric acid is not as bad as you think, actually. It's one of the most produced chemicals on Earth, and not that we would take any from Venus to Earth but it's a good resource for a growing civilization to have access to. And at 50 km above the surface temps are Earth temps and pressure is Earth pressure, Mars is practically a vacuum.  

As for the comment on soil, it's not a big deal. Chemically speaking you have access to most of the elements you need in the atmosphere, and you would want to grow using lightweight hydroponics anyway.

Sort of seperate from this but I am always curious why people were quick to speculate about life on Titan, a place so cold you have methane seas, and write off Venus. Whose to say there couldn't be exotic life forms using supercritical CO2 as a medium? From a kinetic perspective, any chemistry happening on Titan is painfully slow. Venus at least can have some things going at a decent pace. 

Because Co2 is much more different from water than Ch4, and is not normally considered a good alt. solvent for life until recently.

[fredinno]

3 hours ago, AngelLestat said:

What about solar flares?  Earth and Venus had a big shield mass against those, on mars surface is similar than open space.

Mars is not similar to open space, the planet itself protects against 1/2 of the radiation, as it covers1/2 of the horizon. Another 1/4 is covered by the atmosphere. It gets better if you can go into the areas covered by regional magnetospheres.

3 hours ago, AngelLestat said:

Venus is more earth-like, pressure, temperature, gravity, sun radiance, sounds, thermal conduction, etc.

In the clouds.

Also, "sounds?" I don't ever remember anyone sending a microphone to Venus...

Mars is more earth like in daytime/night cycles, land ('good' soil for crops), climate (is like Antarctica), geological processes (volcanoes, glaciers, water flows)...

3 hours ago, AngelLestat said:

Why it is more scientifically useful?  In venus you can improve our climate models to understand with precision what would happen with the climate change here on earth and the best way to stop it.  You can study the ground and its big atmosphere with almost no resources, because the floating habitat can be in any place of the planet without any trouble with transport.  

And on Mars, you can study the closest thing to a habitable planet aside from Titan (which is a moon, not a planet). Also, scientists seem to like Mars more, so that's something

3 hours ago, AngelLestat said:

No, the deployment happens at low speeds, that is why you have a parachute..  and you have plenty of time to open.

That's the thing. Have we ever opened a airship in hurricane-speed winds? No? I think that answers the question. You're making it out to be too easy.

3 hours ago, AngelLestat said:

Mars does not have much water at low latitudes neither, the mining in venus would be more cheap than mars for sure.
1-venus has more heavy elements than mars
2-you can use venus temperatures to reduce the amount of energy to shape metals, in the aluminum case you will have to rise the temperature only 200 degrees, for other metals ther energy save is not much, but it helps.
3-very easy to collect those metals for any kind of floating habitat, because these habitats can be in any place they want over the planet without spending almost no energy, in mars you need infrastructure or special vehicles wasting a lot of minerals to transport those minerals to any location of need.
4-You get a lot more energy in venus, and you need energy to mine, on mars you need to use solar panels at very low efficiency storing the energy for night.
5-sulphuric acid is the chemical substance more used in industry, is perfect to separate metals in mining or many other uses, more if you use it under pressure at high temperature, they become much more effective.

This again...

Look, I know you really like Venus, but if you need to pretty much build submarines to mine (on Venus), compared to a spacesuit+ normal tunnels or open pit mines, Venus loses. Big time.

Also, industry is not going to settle on Venus (except maybe in orbit), the gravity well is too high to make it economical.

3 hours ago, AngelLestat said:

Also if you are thinking in terraform mars..

I never said that.

[peadar1987]

9 hours ago, AngelLestat said:

But you are only counting fatal cases, radiation effects goes beyond that, you have a Deterministic effects and Stochastic effects, the seconds happens at random with random effects.
Most of those effects can not be related or detected, it can change your adn in a way you pass a fatal or nonfatal error to your children or grandchildren, or it can affect your health in many different ways.
Chernobyl, Hiroshima and Nagasaki happen in places where the documentation could be hidden or was not done too seriously.  Then you need a big team trying to recover all those documents with different symptoms and  death circumstances, in which most of the doctors instead put the real possible cause they just note the obvious "heart stroke". (my dad as evidence who die from cancer).
What are the effects of radiation in pregnant women?  Or even in sperm?  How a baby develops under those radiation levels?  You will be calm if it was your baby the one that is growing under 240sv his/her whole life?
What about solar flares?  Earth and Venus had a big shield mass against those, on mars surface is similar than open space.
The issue is clear, and if you want to have a permanent colony in mars, you need to at least guarantee that your habitants will not get more than 20 sv by year.
Any other value or the posture of said "radiation is not a problem" is not serious enough (and you know that)  

Nope, the 5.5% of developing cancer per Sievert absorbed is a Stochastic effect, and that's all cancers, not just fatal ones. There are some other stochastic effects like developing birth defects, to be sure. These are most severe if the dose is absorbed during the first few weeks of pregnancy. If you're on Mars, the simplest solution is to go underground for the first few months of pregnancy.

Stochastic effects aren't mystical or magical, they can be analysed perfectly well for large sample sizes and used to make probabilistic predictions, even if they can't give deterministic results.

Multiple studies and meta analyses have been carried out on huge sample sizes of Chernobyl, Hiroshima and Nagasaki survivors. If your response to the results of that are "they fudged the data", so be it, but it's favouring your own anecdotal evidence against peer-reviewed research, which is unscientific. I'm sorry to hear about your dad, but his death from cancer will have been logged as a cancer death. Nobody can say for sure what that particular cancer was caused by, but they will be able to look at the incidences of cancer, heart disease, stroke, or whatever for the whole population, and make a statistical conclusion based on that data.

In any case, my original post was simply talking about how Mark Watney would not have died of radiation exposure on Mars, not about the chance his kids would have cleft palate.

[AngelLestat]

10 hours ago, fredinno said:

Mars is not similar to open space, the planet itself protects against 1/2 of the radiation, as it covers1/2 of the horizon. Another 1/4 is covered by the atmosphere. It gets better if you can go into the areas covered by regional magnetospheres.

You have 3 main radiation sources in space, the main is the sun, then you have background radiation and high energy particles. As you said you have 1/2 from the horizon and 1/4 for the atmosphere, so if a solar flare happens in day time, is almost the same than if you are in open space, you can get a fatal dose, that is the main point.  

10 hours ago, fredinno said:

In the clouds.
Also, "sounds?" I don't ever remember anyone sending a microphone to Venus...

You dont need to, partial vacuum does not transmit very well sounds, of course in mars does not matter much because you will never be without a space suit anyway.

10 hours ago, fredinno said:

Mars is more earth like in daytime/night cycles, land ('good' soil for crops), climate (is like Antarctica), geological processes (volcanoes, glaciers, water flows)...

You have day/time cycles in venus too, they last 60 or 70 hours. About land.. forget you will use soils, is a waste of space and resources, something that you can not afford in mars.
Climate ?  you have almost vacuum..  you may said temperature at low latitudes are similar to the antartica with a very different thermal conduction.
Volcanoes?  Mars is geological death, venus is like earth in that sense, it seems even more active.
In venus the mountains have metals glaciers.

10 hours ago, fredinno said:

And on Mars, you can study the closest thing to a habitable planet aside from Titan (which is a moon, not a planet). Also, scientists seem to like Mars more, so that's something

I am still waiting your source for the "scientist who had an educated guess on mars gravity being non harmful for humans"
The most close to an habitable place is venus clouds for all the things already mentioned, there is no place in the solar system more similar to earth.

10 hours ago, fredinno said:

That's the thing. Have we ever opened a airship in hurricane-speed winds? No? I think that answers the question. You're making it out to be too easy.

Because is too easy..  What hurricane winds?  Venus atmosphere rotates 3 times slower than earth atmosphere, and that speed is nothing compared with reentry speed.
 

10 hours ago, fredinno said:

This again...
Look, I know you really like Venus, but if you need to pretty much build submarines to mine (on Venus), compared to a spacesuit+ normal tunnels or open pit mines, Venus loses. Big time.
Also, industry is not going to settle on Venus (except maybe in orbit), the gravity well is too high to make it economical.
I never said that.

Is not about what I like or not, is about what has sense and logic and what has not.
The airships vehicles (that I call submarines just because they can go down or up in a fluid which is more dense than our atmosphere), but they are not similar in construction, design or cost, they dont need a pressure hull and these vehicles just transport the resources, they dont mine.
Again if you want to compare, lets compare how much cost the transport to any floating habitat or city in venus and how much cost the transport in mars.
How much cost extract heavy elements in venus or in mars?  I already explain and point each of the venus pros over mars.   There is no way that mars would have cheaper mining cost than venus, only you can disprove the points I made.
Why industry would not settle in venus?  go back few pages in this topic, I explain how a local economy works with real examples here on earth.

4 hours ago, peadar1987 said:

Nope, the 5.5% of developing cancer per Sievert absorbed is a Stochastic effect, and that's all cancers, not just fatal ones. There are some other stochastic effects like developing birth defects, to be sure. These are most severe if the dose is absorbed during the first few weeks of pregnancy. If you're on Mars, the simplest solution is to go underground for the first few months of pregnancy.

Stochastic effects aren't mystical or magical, they can be analysed perfectly well for large sample sizes and used to make probabilistic predictions, even if they can't give deterministic results.

Multiple studies and meta analyses have been carried out on huge sample sizes of Chernobyl, Hiroshima and Nagasaki survivors. If your response to the results of that are "they fudged the data", so be it, but it's favouring your own anecdotal evidence against peer-reviewed research, which is unscientific. I'm sorry to hear about your dad, but his death from cancer will have been logged as a cancer death. Nobody can say for sure what that particular cancer was caused by, but they will be able to look at the incidences of cancer, heart disease, stroke, or whatever for the whole population, and make a statistical conclusion based on that data.

In any case, my original post was simply talking about how Mark Watney would not have died of radiation exposure on Mars, not about the chance his kids would have cleft palate.

I said that no all stochastic effects can be related or measured, and that holds true.
Read exactly what is my point in that matter and the possible issues.
We don't have any evidence of that, and words like "multiple studies, meta analyses" does not solve that either.  I am not providing anecdotal evidence, I only supporting 1 real true.. radiation can change your dna on ways that can not be predicted, it can damage cells in similar ways.
I read many studies on radiation effects, and in all those studies is mentioned all the things that escape from the study reach, because they can not be easy related or proved, or some health issues may take generations to appear.
If you take that as "well nothing happens because is not mentioned, so lets drink some margaritas in mars surface with permanent stay", that is not serious enough.
Now lets take the posture that you are right, and there is no other issues than the ones who could be proved in the studies, so that will decrease the life expectancy but maybe no so much.  Still, you need to convince people to play lottery with their life each day.
So dont try to said that mars radiation is not an issue, is clear that it would not be mars cities if we dont solve the radiation issue first.  So in the poles is easier, you go under the ice, at higher latitudes would be more expensive.
The same than venus has an extra cost than mars to obtain water, I am not trying to get rid of venus cons, we should include all pros and drawbacks to compare.

 

[fredinno]

1 hour ago, AngelLestat said:

You have 3 main radiation sources in space, the main is the sun, then you have background radiation and high energy particles. As you said you have 1/2 from the horizon and 1/4 for the atmosphere, so if a solar flare happens in day time, is almost the same than if you are in open space, you can get a fatal dose, that is the main point.  

Quote

You can need a "storm shelter", which is also needed for interplanetary HABs, and is one of the most basic required equipment for interplanetary spaceflight. If we can't build one, you can't go beyond the Earth-Moon system, simple as that.

1 hour ago, AngelLestat said:

You dont need to, partial vacuum does not transmit very well sounds, of course in mars does not matter much because you will never be without a space suit anyway.

And on Venus, you'll be without a suit to protect yourself from the sulfuric acid and cool yourself? And sound will need to be via radio, it's going to be impossible to hear anyone in the winds.

1 hour ago, AngelLestat said:

You have day/time cycles in venus too, they last 60 or 70 hours. About land.. forget you will use soils, is a waste of space and resources, something that you can not afford in mars.
Climate ?  you have almost vacuum..  you may said temperature at low latitudes are similar to the antartica with a very different thermal conduction.
Volcanoes?  Mars is geological death, venus is like earth in that sense, it seems even more active.
In venus the mountains have metals glaciers.

And those volcanoes will not be accessed by humans, or even be visible, so it doesn't count. Mars is barely still active.

Climate: https://en.wikipedia.org/wiki/Climate_of_Mars

It's like Antarctica. But that's still Earth climate Mars is similar too.

And Mars has similar same inclination and day/time 24h nighttime cycles as Earth.

1 hour ago, AngelLestat said:

I am still waiting your source for the "scientist who had an educated guess on mars gravity being non harmful for humans"

http://forum.nasaspaceflight.com/index.php?topic=14552.0

1 hour ago, AngelLestat said:

Because is too easy..  What hurricane winds?  Venus atmosphere rotates 3 times slower than earth atmosphere, and that speed is nothing compared with reentry speed.

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

https://en.wikipedia.org/wiki/Saffir%E2%80%93Simpson_hurricane_wind_scale

1 hour ago, AngelLestat said:

How much cost extract heavy elements in venus or in mars?  I already explain and point each of the venus pros over mars.   There is no way that mars would have cheaper mining cost than venus, only you can disprove the points I made.

I'm going to simplify this for you:

Venus: Build a submarine, go down to the surface and mine

Mars: Mine

Which one is easier?

1 hour ago, AngelLestat said:

So dont try to said that mars radiation is not an issue, is clear that it would not be mars cities if we dont solve the radiation issue first.  So in the poles is easier, you go under the ice, at higher latitudes would be more expensive.

It is a problem. But it's less than trying to get in and out of an Earth-like Gravity well and atmosphere. You can build habs in soil.

[AngelLestat]

2 hours ago, fredinno said:

You can need a "storm shelter", which is also needed for interplanetary HABs, and is one of the most basic required equipment for interplanetary spaceflight. If we can't build one, you can't go beyond the Earth-Moon system, simple as that.

Yes you can.  There is always a solution..  the problems is for those that are making exploration far from the shelters, I dont remember the amount of time to react you have, and you will need at least 2 or 3 sats monitoring the sun close to the mercury orbit.   

Quote

And on Venus, you'll be without a suit to protect yourself from the sulfuric acid and cool yourself? And sound will need to be via radio, it's going to be impossible to hear anyone in the winds.

Why cool yourself?  53km you are more than fine.  You dont need airtight suits.
About the wind..  what wind??   something that I always explain over and over about venus, is that if you are in a floating habitat, there is no wind, because you are traveling with the wind, so your apparent wind relative to you is close to zero.  And venus has very low shear, much less than earth.

Quote

And those volcanoes will not be accessed by humans, or even be visible, so it doesn't count. Mars is barely still active.

They will be very visible. our eyes and brain makes can get used to big changes of light.  Our brains let us see a tree shadow and the clear sky at the same time without problem, but in reality, if you take a picture, the shadow is super dark and the sky is overexposed.  You can see fine on a typical overcast day here on earth, and that would be 10 to 5 times more darker than the venus surface.
Venus surface: receives 20 times less light than at 53km (cloud level), this mean 5000 lux (surface).
Earth on day receives 100000 lux, and a typical overcast (no the most dark ones) 1000 lux.

Quote

http://forum.nasaspaceflight.com/index.php?topic=14552.0

That is not even explained..  You said scientist.

Quote

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

https://en.wikipedia.org/wiki/Saffir%E2%80%93Simpson_hurricane_wind_scale

......

You know that earth atmosphere rotates in conjunction with the earth at 1200kwh?  you can add +- 200kmh depending the wind with respect to earth, so when a ship re enter in the atmosphere (depending if is does from the same direction or opposite direction) it needs to brake around 25000kmh +- 1200 kwh. (or more if you are returning from mars or venus with aerocapture)
In the venus case can be similar 25000kmh +- 400kmh (this is the wind rotation speed, because the surfaces rotates very slowly)
Other thing, venus does not have high shears (fast change of wind), turbulance or wind shear is many times significant in earth atmosphere than on venus. 
 

Quote

I'm going to simplify this for you:
Venus: Build a submarine, go down to the surface and mine
Mars: Mine
Which one is easier?

haha, so you can get all your minerals from the same location?  concentrations does not matter for you?
You settlements are only in one place?  You dont take advantage of the poles to get cheap energy or habitats?
And even in the hypothetical case that you get all from one place, venus would be still cheaper due high concentrations, extra energy and the other pros.

Quote

It is a problem. But it's less than trying to get in and out of an Earth-like Gravity well and atmosphere. You can build habs in soil.

export cost is higher in venus.. but at the beginning you are more concern about import cost in which venus is lower than mars.  With the time tech grow and deltav cost becomes negligible.

Edited April 6, 2016 by AngelLestat

[fredinno]

33 minutes ago, AngelLestat said:

Yes you can.  There is always a solution..  the problems is for those that are making exploration far from the shelters, I dont remember the amount of time to react you have, and you will need at least 2 or 3 sats monitoring the sun close to the mercury orbit. 

There are things called pressurized rovers, which are big enough to have their own storm shelters. You need those for long duration missions anyways.

34 minutes ago, AngelLestat said:

About the wind..  what wind??   something that I always explain over and over about venus, is that if you are in a floating habitat, there is no wind, because you are traveling with the wind, so your apparent wind relative to you is close to z

It still carries sound away, and you still don;t want tp expose your face to sulfuric acid in the atmosphere.

35 minutes ago, AngelLestat said:

haha, so you can get all your minerals from the same location?  concentrations does not matter for you?

And concentrations on Venus don't matter? Is Venus' crust made of 100% metals?

[Bill Phil]

@AngelLestat

Wind isn't constant. At different altitudes ( a few tens of meters in some cases) the wind can be vastly different. Not only that, but at different locations it's different. 

Not only that but it complicates things. It limits your launch window unless you have active propulsion. The wind could push you off the equator, and pretty far north.

[AngelLestat]

6 hours ago, fredinno said:

There are things called pressurized rovers, which are big enough to have their own storm shelters. You need those for long duration missions anyways.

Storm shelter?  you mean mars dust storm?  but we were talking about solar flares, you need a shelter against radiation, no practical vehicle can provide you that, you need at least 2 meters of dirt between you and the radiation.
The question here is how much time of warning you have before the radiation reach mars.

Quote

It still carries sound away, and you still don;t want tp expose your face to sulfuric acid in the atmosphere.

And concentrations on Venus don't matter? Is Venus' crust made of 100% metals?

There is no wind!  the sound is not carried away!  If it were wind, is becoz you are not traveling at the wind speed, so this wind push you, you get an acceleration until you match the wind speed, then the apparent wind is zero.
The same than a hot air balloon, they dont feel the wind, and that taking into account that earth atmosphere has more turbulence and shear.
About minerals, see the table in the link I post, or search google about metals venus surface.

4 hours ago, Bill Phil said:

@AngelLestat

Wind isn't constant. At different altitudes ( a few tens of meters in some cases) the wind can be vastly different. Not only that, but at different locations it's different. 

Not only that but it complicates things. It limits your launch window unless you have active propulsion. The wind could push you off the equator, and pretty far north.

Come on bill, you know me... You think that I lack of info about venus?    I read a lot of books just to search and understand each value that I found..
I made this resume to help KSP forum users to know the most interesting info about venus without the need to read and search over many weeks as I did:

The best book that I read about venus winds is this:
http://www.mps.mpg.de/3183924/Dissertation_2010_Piccialli__Arianna1.pdf

This is the one that help me to link very different data that I gather from different sources, at that time I did not find much agreement with different studies, then I understand and I could relate different measures to different altitude and latitudes, I notice that even the NASA team who did the Havoc mission concept, they were wrong with the zonal and meridional winds they quote for that mission requirement, which is a big difference because they would save at least half of power and storage to counter the meridional winds they claim.

Answering your point:  Yeah.. wind speed increase with altitude, then with different day hours (sun inclination) and other effects depending latitude. But the change is negligible in 200 meters for example, less for the height of your airship.
To harvest a good wind gradient, you need at least 3 km between your ship and your Kite or Wind Turbine.
Venus climate and weather is very stable, because venus rotation is very slow, so it depends on the atmosphere to equal temperatures, and it makes a perfect job, the difference in temperature at low altitude is the same no matter where you are over venus, the difference in temperature at 53km between the lower to the max latitude (day and night) is still lower than 20 degrees.  Compare with earth big temperature difference...
On lack of strong shear and turbulance happen because clouds are very uniform over the whole planet, this avoid temperature difference between shadows cast and sunlight,  you have only 1 kind of surface (not like on earth, sea and land) which only receives 5% of the sunlight, so the vertical wind currents are negligible.
You have very little water in the atmosphere, so this possibility does not happen either:

Venus surface is 50km below, so any terrain effect on the wind like mountains is also negligible.
So, mostly all effect that produce wind currents or gust here on earth does not exist in venus.
About launch windows, you can launch at any time or day, if you choose the wind direction you save some hundreds of meters by second to reach orbit, but almost nothing, the wind always goes from east to west, so this avoid the crosswinds that sometimes you have on earth.

All these conditions plus density, makes Venus the perfect place for airships or floating habitats, if you need to build airships here on earth you need big hangar to protect the airships from the winds meanwhile is on construction, there is no need there, with special procedures it become very simple.
That is why I always said that Venus is perfect the way it is, although I will like more water.

Edited April 7, 2016 by AngelLestat