Mars Terraforming Thread

[Bill Phil]

The biggest problem with terraforming Mars, besides actually doing it, is the low gravity. It might have adverse affects on human physiology. And if it doesn't, it will certainly cause the Martians to be unable to go to Earth, or any other high gravity world.

The magnetosphere does little to help planets besides retaining an atmosphere for a very long time. Without it, Mars is fine.

The thing that protects you the most from radiation is the atmosphere. Just look at the ISS. It's in a very tight orbit around Earth, and it receives about as much radiation as the surface of Mars. But on Earth's surface, the radiation is reduced by a very large amount. And that's only a few hundred kilometers of air, with the majority of it being very low density.

The atmosphere of Mars would have to be pretty big, since the gravity is low. But that atmosphere would help with blocking radiation so much, that it probably wouldn't be much worse on Mars' surface than on Earth's, post-terraformation.

"Should we terraform" is a bigger question than "can we". Humans have a long history of changing the environment to suit our needs. Houses, cities, highways, farms, etc. Changing a planet is not that terrible. That is, if there isn't life there. If there is life, we should not terraform. If there isn't, then let's terraform.

How to terraform? Raise Mars' temperature. That's the first step. That might require a thicker atmosphere anyways, though. Then you give it a habitable atmosphere. Then you introduce enough water to make a suitable water cycle, enough carbon for a carbon cycle (which might already be there), and enough nitrogen for a suitable nitrogen cycle. Then you add life, if you haven't already.

We should probably have colonies on the surface during the terraforming, as well. It will definitely take centuries, if not millenia.

[Newt]

The biggest problem with terraforming Mars, besides actually doing it, is the low gravity. It might have adverse affects on human physiology. And if it doesn't, it will certainly cause the Martians to be unable to go to Earth, or any other high gravity world.

Indeed. And at this stage we have not really been able to place people in such an environment to do any experiments at all. There are many questions to be asked about what the gravity will do, and even in most of the best outlooks, it will be difficult to raise children fully on Mars and allow them to travel to Earth unaided, they simply will be exhausted by lifting the weight of their body.

The magnetosphere does little to help planets besides retaining an atmosphere for a very long time. Without it, Mars is fine.

To all of you maintaining this refrain, I request citations. The radiation from the Sun, okay, perhaps is safe at Mars' distance. But the main issue here is not solar radiation, as Jonboy noted, it is cosmic radiation. This is far more high-energy, far more difficult to block conventionally, and remains a threat to astronauts. On the trips to the Moon, the impact was minimal, while outside of the magnetic feild, crew noted flashes of light. But over a short part of their lives, the impact was probably not really changing their cancer, or other disease proclivities beyond normal. Under the multi-year mission outline, or especially under the foetus-grave on Mars outline, the threat will not be negligable, the effect will be massive.

Studies to look at this are, from my findings, difficult. The number of people who have been exposed to interplanetary space level cosmic radiation is tiny, but what we do understand is somewhat alarming. On a relativley short mission, there have been suggestions that possibly 5% of a persons cells could be killed by this radiation alone, and more in the brain. Being not particularly well versed in space medecine, or medecine generally, this may alarm me unduly, but I doubt it. Building a small atmosphere for Mars would help some, but this radiation, is a constant that happens all over the Universe. You cannot move away from it, you have to block it. On Earth, we are safe, on Mars, we are not.

[Bill Phil]

My point is that radiation is blocked more by the atmosphere than the magnetosphere. This can be seen by comparing the radiation from a few hundred kilometers above the surface (LEO, ISS) to the surface radiation. Both are within the magnetosphere, and yet, the atmosphere makes a great difference in the radiation received. Giving Mars an atmosphere similar to Earth's will add radiation protection. Yes, the magnetosphere protects against solar wind, but the atmosphere is the most important aspect of Earth, without it, liquid water is impossible. Life is impossible. It protects from radiation, and even helps to equalize the temperatures of the day and night side.

The astronauts going to the Moon didn't have hundreds of kilometers of air to protect them, just a few millimeters of aluminum and the structural members of the spacecraft.

Astronauts going to Mars will have more radiation threat from their long journey than the time they spend on Mars' surface.

I don't really think a citation is necessary, since looking at data from LEO and Earth's surface should be proof enough.

[Newt]

I agree about radiation in general, there is a high amount of evidence to support what you are saying and I have read material that supports it. My concern is cosmic background radiation, which is in some ways similar to the radiation you seem to be talking about, but is in many ways very different. It is very difficult to block, such that Apollo hardly tried; the stay outside of the magnetic feild was breif, and the danger limited. The ISS likewise does not care too much about this threat, as it resides in the secure environment of LEO.

But 'Deep Space', is different. Past the magnetic feild of the Earth, this is a pervasive and perpetual threat. Sheilding is difficult, the high energy of the particles makes them often create lower energy particles when efforts are made to block from cosmic rays. On Mars, the atmosphere, especially the bloated one of a terraformed planet, would sheild some from these, but I am concerned that it would be sufficient to prevent damage.

There are studies that suggest this may pose threats of high increases of conditions such as Alzheimers on long duration spaceflights, and that is only assuming a trip to Mars and back, not a colony. Of course, the flight is more dangerous than the surface stay, but we should not loose site of the latter, especially if a colony is the proposition.

Edited May 28, 2015 by Newt
spelling

[Jonboy]

Until an atmosphere or magnetosphere odds introduced (which would require technology FAR beyond what we currently have), any colony would have to rely on being buried under a thick layer of Martian soil to protect against cosmic radiation and solar flares.

IIRC, it would take about 16 feet of Martian soil to provide the same radiation protection as on the surface of Earth. Colonists would be living an underground life, with outside activities limited to only a few hours or less each day. I find it hard to imagine a profitable or successful colony existing in such conditions.

[peadar1987]

For the whole "magnetosphere vs atmosphere" thing, dose rate in LEO averages about 0.5-1.4mSv/day (source), dose rate on Curiosity's trip to Mars averaged 1.8mSv/day (source)

Cosmic rays are still attenuated pretty well by the atmosphere. This graph shows that half of them are already attenuated by 10,000m above the earth's surface. That's after only passing through 1/3 of the atmosphere.

So to reiterate:

-Radiation on the Martian surface will increase your risk of cancer by a small amount, less than 20% for a 2-year mission even if you're completely unshielded. You will not get radiation sickness, you will not need to take special precautions and only venture outside for a few hours at a time.

-An atmosphere 1/3 the thickness of earth's would cut this exposure roughly in half. This would drop the radiation levels to only just above the smallest amount statistically linked to any increase in cancer. Sleep in a shielded hab for 8 hours a day and you are below the threshold, and any increased risk of cancer will be insignificant compared to random noise.

[-Velocity-]

For the whole "magnetosphere vs atmosphere" thing, dose rate in LEO averages about 0.5-1.4mSv/day (source), dose rate on Curiosity's trip to Mars averaged 1.8mSv/day (source)

Cosmic rays are still attenuated pretty well by the atmosphere. This graph shows that half of them are already attenuated by 10,000m above the earth's surface. That's after only passing through 1/3 of the atmosphere.

So to reiterate:

-Radiation on the Martian surface will increase your risk of cancer by a small amount, less than 20% for a 2-year mission even if you're completely unshielded. You will not get radiation sickness, you will not need to take special precautions and only venture outside for a few hours at a time.

-An atmosphere 1/3 the thickness of earth's would cut this exposure roughly in half. This would drop the radiation levels to only just above the smallest amount statistically linked to any increase in cancer. Sleep in a shielded hab for 8 hours a day and you are below the threshold, and any increased risk of cancer will be insignificant compared to random noise.

Don't forget that for Mars' surface gravity of 0.37g, the air column above you has to be 1/0.37 = 2.7 times more massive to sustain the same pressure (as it would on Earth). So if you have 0.3 bars of pressure on Mars' surface, that's about 80% as much atmosphere as what lies above you on Earth. The radiation would not be serious at all. Get the surface pressure up to 0.5 bar, and the surface radiation levels could be even lower than on Earth.

For those asking for a source that the magnetic field would not be necessary to protect you from radiation, yes, I've looked. I could not find one using Google Scholar. I DID READ IT ONCE THOUGH. I just can't remember where. It could have been a bad source, true, but I really doubt it, because it's common sense. Radiation is not some magic bullet that will cut through everything except a magnetic field. Matter stops it, and a terraformed Martian atmosphere would be very massive indeed to create a breathable environment on the surface due to the low gravity.

But, to a certain extent, do we really need a source? The fact that we even exist is proof you don't need a strong magnetic field to protect life from radiation. Since we became vertebrates, our ancestors have survived hundreds or up to a few thousand reverals of Earth's magnetic field. During these reversals, Earth's magnetic field effectively disappears, sometimes for more than a thousand years. We exist, and humans have survived them, as the last one occurred less than a million years ago. Since the Earth is under magnetic field reversal less than 1% of the time, it has a negligible effect on atmospheric loss, because (again, for the 10 millionth time in this thread), it takes many, many millions of years for an atmosphere not protected by a magnetic field to erode. In the last 500 million years, the total integrated time Earth has faced the Sun without a magnetic field protecting it is probably only about 1 million years (say, 1000 field reversals of 1000 years each).

Edited May 28, 2015 by |Velocity|

[Wesreidau]

And since vertebrates first crawled the Earth, we have had mass extinctions, genetic mutations and birth defects. Furthermore the magnetic field does not disappear during a reversal, it merely decentralizes. The field is still there and still shields us from cosmic rays. The theory that it disappears is out of date, it seems.

[baggers]

"Should we terraform" is a bigger question than "can we". Humans have a long history of changing the environment to suit our needs. Houses, cities, highways, farms, etc. Changing a planet is not that terrible. That is, if there isn't life there. If there is life, we should not terraform. If there isn't, then let's terraform.

I notice we haven't wait that much for "changing" our own planet or life. Why bother much for others? Doesn't a "museum of natural life of Mars/Tau Centuri/XX-01V" be sufficient?

[peadar1987]

And since vertebrates first crawled the Earth, we have had mass extinctions, genetic mutations and birth defects. Furthermore the magnetic field does not disappear during a reversal, it merely decentralizes. The field is still there and still shields us from cosmic rays. The theory that it disappears is out of date, it seems.

There has been no statistical link found between geomagnetic reversals and mass extinctions (wiki). During the last reversal, the field dropped to about 5% of its current value.

The vast majority of dose carried by cosmic rays (>90%) is in the range of <0.5GeV (source). 1GeV particles have a penetration depth in lead of about 50cm (about 5km in air) (source). Penetration roughly scales with the energy of the particle, so a 0.5GeV particle will have a penetration depth of about 2.5km in the air (This means after 2.5km, the dose is reduced to 1/e, or just under 40%.) Seeing as the majority of the dose is going to be at even lower energies than this, the penetration depth will be even shorter.

There's no two ways about it, cosmic radiation is stopped very effectively by an atmosphere. We get, on average, about 0.4mSv a year in dose from cosmic rays on the surface of the earth. Compare that to the 0.5-1.4 mSv a day in LEO. You're already cutting out 99.9% of the incident radiation, and that's only the most highly energetic and penetrating particles, which haven't already been filtered out by the magnetic field. If there wasn't a magnetic field, the atmosphere would actually block out a far greater proportion of the radiation hitting it.

[Findthepin1]

Mars gets half of Earth's radiation (ignoring all but distance from the sun) because it is 1.5 times further from the sun and it is on a per surface area basis. Since its gravity is 38% of Earth's, any Earth-like atmosphere it gets would be about 2.7 times higher, so at LEO-like radiation levels, 0.4 atm on Mars would protect you more than 1 atm on Earth. This doesn't take into account that Mars gets half of Earth's radiation, in which case we need only 0.2 atm on Mars to keep radiation levels the same as on Earth at sea level. I think.

[Wesreidau]

I thank you for well-reasoned and factual replies, Peadar. It seems I overestimated the danger of cosmic rays. I still have my concerns about lifetimes of exposure and especially the effect of otherwise manageable levels of radiation on pregnant women, but the question of terraforming Mars to surface habitability is a debatable one again.

[peadar1987]

I thank you for well-reasoned and factual replies, Peadar. It seems I overestimated the danger of cosmic rays. I still have my concerns about lifetimes of exposure and especially the effect of otherwise manageable levels of radiation on pregnant women, but the question of terraforming Mars to surface habitability is a debatable one again.

No worries, I'm a bit of a radiation nerd, and once you brought up the topic, I was interested, and decided to crunch the numbers. In my opinion, the biggest hurdles will be the nastiness of the Martian dust, and the effect that living in 0.4g will have, both of which are pretty much unknown quantities.

[RuBisCO]

http://forum.kerbalspaceprogram.com/threads/70211-Terraforming-Mars

http://forum.kerbalspaceprogram.com/threads/68857-Terraforming-Venus

Please read "Technological Requirements for Terraforming Mars" by Robert M. Zubrin. [Pioneer Astronautics] and Christopher P. McKay [NASA Ames Research Center] http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

It is the most comprehensive report on how we could terraform mars.

Assuming Mars has enough CO2 and water frozen/sequestered into the soil, a big assumption, then all we need todo is raise the temperature enough to cause a run way greenhouse effect. How do we do that?

1. We could build giant mirror out of asteroids or mars moon's, place them in a pseudo Mars-Sun L2 position (they would basically be solar sails so not that hard to move) and have them blast the poles with sunlight. With enough mirror and I mean ENOUGH to equal the sunlit surface area of mars and then some we could bring up the total solar flux of mars to earth level, downside there would be no "night", upside half of mars's day would have the sun, the other half would have many many mirror suns, that would be a sight, seeing the raise of a ring of "suns"!

2. Greenhouse gases: We could produce super powerful greenhouse gasses on mars, sulfur hexafluoride is the most powerful greenhouse known to man, it is also very stable and completely inorganic, we could make it on mars by mining salts. Zubin assumes the use of Halocarbons, several hundred tons a day via a few GWe nuclear power station and a mining and production colony of a few thousand, could produce enough super-greenhouse gas to bring up mars temperature and pressure (assuming enough CO2 released from the soil) in under a century to levels high enough that humans could walk around without a space suit, still need oxygen though.

3. Crash comets/asteriods made of Water/Ammonia/CO2 into Mars. If mars does not have enough CO2 and water in its soil then it will need to be imported. The amount needed would be phenomenal and would take thousands of fusion power spaceships many centuries to bring in.

Concerns

Nitrogen: A terraformed mars would likely have an atmosphere made mostly of CO2 and Oxygen, Human could, hypothetically, adapt to high CO2 atmosphere, it is merely a matter of re-buffering our blood's pH balance. No experiment and slowly adapting humans to atmosphere of mostly CO2 have been done. Levels as high as 8% have been used for medical purposes (keep patient's hyperventilating) Ideally we could need a inert gas like nitrogen, which would need to be imported.

Magnetosphere: without it Mars's new atmosphere would slowly be striped away by solar wind, but this is a process that would take millions of years and we could counter that easily. We could also build an orbital ring around mars, consisting of a superconducting wire, charge it up and problem fixed.

Radiation: if the atmosphere of mars can be brought up to and beyond 200 mbar, then the atmosphere will absorb radiation very well. Every 75 mbar is like a meter of water worth in radiation shielding. Lifetime and multi-generational exposures to radiation is not unknown to science, for example consider the town of Ramsar, Iran. If radiation levels can be reduced to 10-100 times background here on earth, that may be perfectly livable without appreciable increases in mutation and cancer. Frankly there is not evidence the LNT model on radiation induce cancer holds true below 100 mSv/yr levels, and tantalizing evidence that it does not.

Gravity: Mars's gravity is only ~1/3 Earths, we have no clue at this time what the health consequences of that gravity will be to humans. This is a question that needs to be answered long before terraform mars.

Edited September 23, 2015 by RuBisCO

[PB666]

Sulfer hexaflouride, high co2 atmospheres, mirrors at L2? lol. nope.

[RuBisCO]

Sulfer hexaflouride, high co2 atmospheres, mirrors at L2? lol. nope.

Do you have an actual argument?

If you believe Mars can't hold the gas for significant amount of time, please see: http://forum.kerbalspaceprogram.com/threads/70211-Terraforming-Mars?p=988493&viewfull=1#post988493

[PB666]

Do you know what you are asking? Calculate the scale.

Secondarily you may have a small source of C and O, you have nowhere near what is needed for H.

L2 orbits where the next outer planet is Jupiter are unsustainable, to make sure they are sufficiently reflective they need to be in a rather large orbit, the larger the orbital radius, the more unsustainable that the orbit is.

[Aethon]

Magnetosphere: without it Mars's new atmosphere would slowly be striped away by solar wind,

The solar wind doesn't pull much gas away from planets. The primary mechanism for gas loss is photo dissociation by UV light, which is less of a factor than was once thought. Mars as it is would be able to hold on to lighter gasses over geological periods. Water is a pretty light weight gas but turbulence mixes atmospheres very well. When water reaches the top of an atmosphere (like Venus) it can be 'split' by UV light and the Hydrogen, having a low molecular weight, can reach escape velocity.

This doesn't happen much on Earth -not because of our stronger gravity, but because of the structure of our atmosphere. The Earths ozone layer tends to prevent convection in the stratosphere which is so cold that water (freezes) precipitates out and falls back down. The amount of water in the atmo. drops by orders of magnitude in a few km altitude at the tropopause, trapping the water lower in the troposphere where most of the solar UV can't get to it and and free Hydrogen has a chance to recombine.

[RuBisCO]

Secondarily you may have a small source of C and O, you have nowhere near what is needed for H.

Neither you nor I nor anyone presently knows how much water is locked away on Mars. So no one yet knows how much H is needed. If we have to bring it in from Kepler Belt, that is technically feasible. Please see the previous terraform mars thread I cited.

L2 orbits where the next outer planet is Jupiter are unsustainable, to make sure they are sufficiently reflective they need to be in a rather large orbit, the larger the orbital radius, the more unsustainable that the orbit is.

These are like solar sails so their position would be psuedo-L2 they would be closer then L2 in a position where sunlight pressure and gravity of mars and sun counteract. Such mirrors would also likely be actively stabilized by secondary solar "flaps"

I get the feeling you want a terraformed world that is passively stable for billions of years. First of all that is unnecessary, second of all that does not existed: The earth for example has only be habitable for complex life for about 500 million years, before then oxygen levels were too low, before then earth went through multiple periods of being complete iced over and being a outwardly barren world, with life only able to hold on under the ice and in the lithosphere. Even during the period that Earth has been habitable it has gone through massive changes that have repeatedly killed off most higher lifeforms. Earth will mos likely no longer be habitable for higher life within 1 billion years as the sun gets bigger and hotter CO2 levels on the earth must get lower or the planet over heats, eventually CO2 levels will get too low for plant life and the planet will get too hot for higher life regardless of greenhouse gases or not.

To increase the habitability of the earth longer we would need to build orbital shades in psuedo-L1, even move the planet to a higher orbit, likely by flying KBO down and having them pass-by give there earth some of there kinetic energy.

All these means that billion year stability of the world is out of the question, not without active stabilization. So if we could terraform mars in a few thousands years and it can be stable for just a few million, upkeep would be rather small.

[PB666]

Neither you nor I nor anyone presently knows how much water is locked away on Mars. So no one yet knows how much H is needed. If we have to bring it in from Kepler Belt, that is technically feasible. Please see the previous terraform mars thread I cited.

These are like solar sails so their position would be psuedo-L2 they would be closer then L2 in a position where sunlight pressure and gravity of mars and sun counteract. Such mirrors would also likely be actively stabilized by secondary solar "flaps"

I get the feeling you want a terraformed world that is passively stable for billions of years. First of all that is unnecessary, second of all that does not existed: The earth for example has only be habitable for complex life for about 500 million years, before then oxygen levels were too low, before then earth went through multiple periods of being complete iced over and being a outwardly barren world, with life only able to hold on under the ice and in the lithosphere. Even during the period that Earth has been habitable it has gone through massive changes that have repeatedly killed off most higher lifeforms. Earth will mos likely no longer be habitable for higher life within 1 billion years as the sun gets bigger and hotter CO2 levels on the earth must get lower or the planet over heats, eventually CO2 levels will get too low for plant life and the planet will get too hot for higher life regardless of greenhouse gases or not.

To increase the habitability of the earth longer we would need to build orbital shades in psuedo-L1, even move the planet to a higher orbit, likely by flying KBO down and having them pass-by give there earth some of there kinetic energy.

All these means that billion year stability of the world is out of the question, not without active stabilization. So if we could terraform mars in a few thousands years and it can be stable for just a few million, upkeep would be rather small.

Dont presume my threshold are so lofty, to be a colony it has to be capable of sustaining on generation. So thirty years, the respiratory viability of earth is a red herring argument. And nasa has taken a number of spectrgraph of soil, one of which i presented on another thread and you can wiki. The level of hydrogen is very low in martian soil and it may not be bioavailable, we would literally have to vaporize the rock to get the water out. That how NASA got the hydrogen peak.

Noone knows where the deeper reservoirs come closest to the surface, but wherever those are they are few and far between, certainly not adequate to terraform.

before we go spewing out misinformation, lets be clear, mars has lost its atmosphere. In that process hydrogen was the first to go. Why, because the environment is reducing. On earth wehn hydrogen is released there are a number of oxidative processes that recapture it, the loftiest of which is uv ozonization and peroxide formation. On mars there is no ozone and uv is less dense than earth. hydrogen is the lightest gas. Reductive process turnover hydrogen and water, but once as hydrogen or methane the gases escape. This dries out the surface layers, along with the direct loss of water. Latent heat from the interior of the planet is suficient to keep water moving towsrd the vapor phase and drying the soil down to its most compact layers. The water is lost. Think about the oceans that cover our planet are 2 kilometers on average deep. If you cannot see a drop of water at the deepest points on mars, common sense tells you that any water must be way below the surface, that the surface must be much drier than land here on earth. It would be like the soil in the atacama desert, as I believe one artcle actually stated. So if you can feasibly extract a livable amount of water from a well drained slope of the atacama and also have enough left over to make propellant or RCS (little nitrogen on mars either) then you can survive. That before you attempt some voyaristic scheme on Mars.

Edited September 24, 2015 by PB666

[RuBisCO]

The level of hydrogen is very low in martian soil and it may not be bioavailable, we would literally have to vaporize the rock to get the water out. That how NASA got the hydrogen peak.

And that tells us nothing about how much water is UNDER the surface.

Noone knows where the deeper reservoirs come closest to the surface, but wherever those are they are few and far between, certainly not adequate to terraform.

and you know this .... how?

before we go spewing out misinformation, lets be clear, mars has lost its atmosphere. In that process hydrogen was the first to go. Why, because the environment is reducing.

You mean oxidizing. If the hydrogen is gone all that is left is oxides and superoxides, assuming UV cleaving of water.

On earth wehn hydrogen is released there are a number of oxidative processes that recapture it, the loftiest of which is uv ozonization and peroxide formation. On mars there is no ozone and uv is less dense than earth. hydrogen is the lightest gas. Reductive process turnover hydrogen and water, but once as hydrogen or methane the gases escape. This dries out the surface layers, along with the direct loss of water. Latent heat from the interior of the planet is suficient to keep water moving towsrd the vapor phase and drying the soil down to its most compact layers. The water is lost. Think about the oceans that cover our planet are 2 kilometers on average deep. If you cannot see a drop of water at the deepest points on mars, common sense tells you that any water must be way below the surface, that the surface must be much drier than land here on earth. It would be like the soil in the atacama desert, as I believe one artcle actually stated.

This is fine logic but there is still evidence for glaciers covered over by sand and dust and extensive amounts of permafrost across the planet.

http://news.discovery.com/space/buried-mars-glaciers-are-brimming-with-water-150408.htm

"Scientists suspect the thick layer of dust covering the ice has saved if from evaporating out into space."

http://www.icr.org/article/water-activity-mars-landscapes-sedimentary-strata/

"The geomorphological evidence suggests that the water, even in the "Oceanus Borealis," was not on the Martian surface for prolonged periods. Instead it resided nearly all the time, except for brief spectacular episodes, within or beneath semi-permanent, ice-rich permafrost. This ice-rich layer, about 1-2 kilometers thick in equatorial areas and 5-6 kilometers thick at the poles, is documented by a variety of geomorphological features.13 These include various types of flow-lobed ejecta blankets, debris flows, lobate debris aprons, and polygonally-cracked terrains."

In short mars certainly has more water than atacama desert (assuming atacama desert does not hid glaciers a few meters under its surface). Now does it have enough to make oceans, probably not, questions to be answered is how much water does mars need to be habitable and to what degree, those questions simply can't be answered with the minimal amount of data we have now.

But even if we do need to import water that is not impossible. Perhaps I'm interpreting the thread differently then you: I'm stating that it is hypothetically feasible to terraforming mars, I'm not saying we should. With present to near term technologies it is likely we could bring up Mars's atmospheric pressure and temperature to levels human's could live in without a spacesuit (but still need a respirator and jacket) in a few centuries at most. Breathable air would take a millennia or more, and a lush wet Mars may require comet imports. Do you disagree with assessment being possible?

[PB666]

You mean oxidizing. If the hydrogen is gone all that is left is oxides and superoxides, assuming UV cleaving of water.

Given the high levels of C02 and carbon monoxide, which wants to be oxidized and low levels of O2, and the level of reduced metals in the martian soil, I would say it is relatively reducing compared to earths atmosphere.

This is fine logic but there is still evidence for glaciers covered over by sand and dust and extensive amounts of permafrost across the planet.

The metal/silicate dusts in concentrations would infiltrate the ice, ice sublimes under low pressure, fine dust will slow it down but will not stop it, over time the dust will sort around cavities in the ice, exposing more of it.

There is no useful proof of the subterranean water, its quantity or its depth. Although I am sure it exists, I am also sure that it is not close to the surface, and only a fool would believe they could terraform a whole planet with an unknown amount of water. Even if that is the case you have to split water, into hydrogen and oxygen, and the hydrogen needs to be bound to something, hydrogen does not like to be bound to metals, for the most part, and there is no nitrogen, very inadequate amounts of carbon, mainly CO2.

In short mars certainly has more water than atacama desert (assuming atacama desert does not hid glaciers a few meters under its surface). Now does it have enough to make oceans, probably not, questions to be answered is how much water does mars need to be habitable and to what degree, those questions simply can't be answered with the minimal amount of data we have now.

Proof? This is nothing more than wishful thinking by a mars colony dreamer. The proof of the pudding is in the eating, our probes are down there, beaming lasers at the rocks, there is water, but its not anywhere near enough to terraform a planet, its about the level where you might be able to have a green house dispersed every few kilometers on the surface, self-contained and pressurize to about 1/2 earths atmosphere. To say terraform and start throwing water around as the source of hydrogen for plants and oxygen for the atmosphere means that you have done the homework, you have drilled down into some fantastic reservoir and found the water, water buried deep underground is liquified by latent heat, so where is the ice crystals in the martian dust?

[RuBisCO]

Given the high levels of C02 and carbon monoxide, which wants to be oxidized and low levels of O2, and the level of reduced metals in the martian soil, I would say it is relatively reducing compared to earths atmosphere.

Well given the high level of oxides and peroxides in the surface soil I would say it is oxidizing. Think about it: when the hydrogen was stripped way from the oxygen via UV cleaving and solar wind stripping, where did the oxygen go? I think the problem here is your just looking at the present atmosphere, all that would be changed if terraformed, via what we can get from the soil.

The metal/silicate dusts in concentrations would infiltrate the ice, ice sublimes under low pressure, fine dust will slow it down but will not stop it, over time the dust will sort around cavities in the ice, exposing more of it.

Fine logic again, but it conflicts with the present evidence of glaciers and permafrost on mars. Either the evidence is all wrong or your theory on what should happen is wrong. Look if we saw a rock floating in mid air and you say "no it should fall" well sure it should, but clearly there is a mechanism keeping it afloat! One can't deny evidence simply because it is counter to basic explanations of what should happen.

There is no useful proof of the subterranean water, its quantity or its depth. Although I am sure it exists, I am also sure that it is not close to the surface, and only a fool would believe they could terraform a whole planet with an unknown amount of water.

I'm pretty sure that I specified that we need to know these things BEFORE trying to terraform mars.

Even if that is the case you have to split water, into hydrogen and oxygen, and the hydrogen needs to be bound to something, hydrogen does not like to be bound to metals, for the most part, and there is no nitrogen, very inadequate amounts of carbon, mainly CO2.

Split the water.... ok clearly we are talking about different things!

As for the CO2, we do not know how much CO2 is sequestered in the soil, please see the link by Zubin that it is possible that hundreds of mbar of CO2 is simply sequestered into the soil and all that is needed is to raise mars's temperature enough to start a run away greenhouse.

As for nitrogen, yes the amounts needed to make buffer atmosphere is very limited, but again it may be unnecessary: http://newmars.wikispaces.com/Minimally+Terraformed+Martian+Atmosphere

Proof? This is nothing more than wishful thinking by a mars colony dreamer.

LOL! I'm a transhumanist, I really have no hope for HUMAN colonization of space, all I'm saying is that it is technically possible.

The proof of the pudding is in the eating, our probes are down there, beaming lasers at the rocks, there is water, but its not anywhere near enough to terraform a planet

How much is needed? Give us a number, and provide proof why.

To say terraform and start throwing water around as the source of hydrogen for plants and oxygen for the atmosphere means that you have done the homework, you have drilled down into some fantastic reservoir and found the water, water buried deep underground is liquified by latent heat, so where is the ice crystals in the martian dust?

¿Que? Again you assume something SHOULD be without acknowledging there could be mechanism that make it as it is.

[PB666]

However, a variety of other features on the surface have also been interpreted as directly linked to flowing ice, such as fretted terrain, lineated valley fill, concentric crater fill, and arcuate ridges. A variety of surface textures seen in imagery of the midlatitudes and polar regions are also thought to be linked to sublimation of glacial ice. Today, features interpreted as glaciers are largely restricted to latitudes polewards of around 30° latitude. Particular concentrations are found in the Ismenius Lacus quadrangle. Based on our current models of the Martian atmosphere, ice should not however be stable if exposed at the surface in the mid-Martian latitudes.^[15] It is thus thought that most glaciers must be covered with a layer of rubble or dust preventing free transfer of water vapor from the subliming ice into the air.

IOW most of the features lie in a zone of oblique sunlight and long harsh winters. None are below 30's preferential sites for colonization because of more constant yearround sunlight. In addition, there is confusion about the dry-ice content of the Ice, it is believed that much of the stores must be carbon dioxide because this would be required to raise atmosphere pressure and ice dust to persist. The Ice deposists below 45' are few and far between, in many of the images they show subsidence on the equitorial flank, which means there are probably generally thick layers of dust covering sublimated ice.

1. The bottom line is yes, Ice on Mars, no not clear how much, one estimate is 1.1 M for the entirety of mars at one time

2. Over 70 degrees this is heavily mixed with CO2, if not entirely CO2.

3. THere is a thick covering of dust particularly in the southern most regions that thens to isolated water.

So as I originally stated, in the equitorial region, where you really want that water, its not there, to liberate that water, you are attempting to liberate from a place that has a poor source of energy. The other problem is that the reason water mobilizes is because mars axis can tilt up to 80 degrees, if that happens and you happen to be on an equitorial region, you could be spending 6 months in darkness.

I also stated we are not ready to terriform mars, before you go marching over doing your Arnold Schwarzenegger impersonation, There are no nitrogen sources, there is no place really effective to store the hydrogen, other than releasing and reducing tons of CO2, and it would require a huge amount of energy to mobilize the water and convert it. If indeed the predictions were correct 1.1 meter of water over the surface is equal to 1/9th of an atmosphere. There would be a 2/16 or 1/8th reduction of that because of hydrogen removal, leaving or about 1/10th atmosphere.

So no, bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzt, still is not an atmosphere. In addition the level of oxygen would be 1/3rd of the 3/10ths of oxygen on earth, so there would be about as much oxygen as the tip of mount Everest.

So it is not a viable atmosphere. Slam about 2 dozen comets into the surface and we can talk about the potential. In addition with the level of radiation plants could not grow, basically doom-world.

The only viable option for mars is to build subterranean elevation after finding decent places were underground water is a prospect. We forget the great oxygenation event here on earth was accomplish by cyanobacterium and early trees, happy as larks to convert CO2 into O2 provided a warm sunnny place. Mars is neither warm or particularly sunny.

[luizopiloto]

Mars needs a core kickstart to be terraformed...