Challenges of Terraforming Mars: Temperature, Air Pressure, and Radiation

[Ryan_m_b]

Hi all--

I wonder if the context of this discussion has been a bit ambiguous. Reading through the posts, it seems folks are sometimes talking passed each other. For example Ryan_m_b is saying very sound things about ecology, whereas PAllen takes a much broader perspective. The context is left pretty open by Nikitin in opening thread, and so it seems to me no one is really out of order here, but everyone is speaking to different levels of speculation/ consideration/ design about Terraforming.

Seems to me, there are at least four levels to look at this project/problem:

You may be interested to read about Technology readiness levels. This is a 1-9 rating system that ranges from basic science to ready-for-market. I would argue that the technology needed for terraforming range from >1 - 3 with the latter only applying to limited areas of research in space and genetic science.

I agree with you that there is scope to speculate on the issue however I feel that such speculation must be kept mainly in your third category with second category forays supported by sound science. I find there's too much handwavium and unobtainium cited in terraforming discussions with the technological hurdles relegated to mere details.

The motivations and ethics of terraforming are very interesting. Personally I think planetary scale terraforming is unethical if there is a chance that there is life (however primitive) on the surface. Purely because if you can terraform a planet you can easily core out an asteroid, give it a spin and terraform the inside to make an O'Neill cylinder. This way you can avoid the hassle of a gravity well, get a far higher habitable surface area per mass and generate a higher diversity of aesthetic biomes across an archipelago of space habitats.

 

[Cosmo Novice]

Part of what makes this whole issue so interesting is that since no one is claiming Star Trek technology (fantasy) that would see terraforming undertaken on the order of a generation or two, the time spans inevitably involved are sufficient for sure to sort of mix type 2 and 3 thinking. Given that a century ago, most people were still using horses and carts to get around, it goes without saying that an awful lot can, and probably will, barring our own destruction, happen in the next century.

This is a school of thought I have encountered a fair bit. While I agree that a lot can change in a century, the nature of development has changed quite a bit, were now getting to the limits of what we know to be physically possible - as in we can postulate what is theoretically achievable and not.

A lot of the sort of technology we are talking about is fantastical in that there are no working models - its essentially a theoretical model, which we know to be accurate given the variables we can plug into it. The fact is GR comes into things now, we understand the laws under which the universe operates, those laws cannot be broken so by extension we can theorise almost all things possible given the correct variables and understanding of the mechanism. Theory and working models are totally different.

I mean in the short term we are talking about redirecting asteroids and creating an entire atmosphere, then developing an atmosphere, somehow getting a magnetosphere, developing an ecology and an earthlike air composition. It all sounds totally pop sci-fi to me and while I love the theory and ideas I feel it is only that.

The motivations and ethics of terraforming are very interesting. Personally I think planetary scale terraforming is unethical if there is a chance that there is life (however primitive) on the surface. Purely because if you can terraform a planet you can easily core out an asteroid, give it a spin and terraform the inside to make an O'Neill cylinder. This way you can avoid the hassle of a gravity well, get a far higher habitable surface area per mass and generate a higher diversity of aesthetic biomes across an archipelago of space habitats.

The ethics are odd, on a speculative note it would be xenocide of a planets entire species if the terraforming process was destructive.

The habitation of an asteroid rather than a planet has many advantages, if being speculative; access to low G areas for the application of certain technologies theorized to be easily developed in low G environments, easy access to low fuel consumption delivery of supplies, essentially you could make the asteroid a mobile home (move it into different orbits using minimal fuel) and then launching missions from close to target, and pribably lots of other things.

However, again being speculative, complete terraforming of a planet is on a totally different scale to anything else and would of course be the best alternative for an alternative settlement for mankind.

Anyway my post has descended into a sci fi novella...

 

[Ryan_m_b]

However, again being speculative, complete terraforming of a planet is on a totally different scale to anything else and would of course be the best alternative for an alternative settlement for mankind.

I would disagree because if we have the capability to terraform other planets we have the capability to maintain Earth's biosphere in a stable manner and surround it with habitats that benefit from all the advantages you mentioned.

 

[Pilot7]

...if you can terraform a planet you can easily core out an asteroid, give it a spin and terraform the inside to make an O'Neill cylinder. This way you can avoid the hassle of a gravity well, get a far higher habitable surface area per mass and generate a higher diversity of aesthetic biomes across an archipelago of space habitats.

I am quite convinced by your reasoning here, maybe that explains why no one came and did this to us...

A note to Cosmo Novice--Even if we accepted physical theory in a close to complete form (I do not, I think GTR and QT are going to get really smashed up before we are through), biology is definitely not as advanced in some analogical way. There are really big puzzles without answers still. And by extension, ecology is really a babe science--I think this is one of the key points articulated in this thread. We have yet to even see the equivalence of the Copernican revolution in ecology, even if maybe we saw some kind of correspondent in biology with the discovery of DNA and the genome.

I think it was Kelvin who said around 1900 something like (my paraphrase): We have now pretty much resolved all the issues in physics, the hard part is done, we are just sorting out some details now...

Needless to say, the next 4 or so years saw most of what comprises contemporary physics conceived. So I wouldn't hold on to your cars and horses too tightly ;-)

 

[Cosmo Novice]

I would disagree because if we have the capability to terraform other planets we have the capability to maintain Earth's biosphere in a stable manner and surround it with habitats that benefit from all the advantages you mentioned.

Sorry I should have explained myself a little clearer. When i talk about a "best option" I am assuming we need terraforming capabilities and massive scale habitable environments as Earth alternatives due to specific reasons. (Nuclear fallout, lack of resources/space due to population etc.)

As a first alternative then maintaining Earths biosphere is the most economical use of recourse - I am effectively stipulating to a point where even with a stable and maintained biosphere there is a NEED to colonise other planets (the main reason I am thinking is production of foodstuffs).

As you have an Asimov quote, to give an anaology I am referring to a Caves of Steel type future civilisation, but with more caves and less country. :)

 

[qraal]

Can increasing the thickness of the atmosphere compensate for lack of a magnetic field?

This is a common misunderstanding. Earth's atmosphere provides us with protection from radiation, not the magnetosphere. There's 10 tonnes of air above every square meter of Earth which stops radiation from flares and high-energy cosmic rays. The magnetosphere diverts the solar wind and coronal mass ejections, but neither of those is especially harmful as their average particle energy is low. That might sound odd, because of those deadly Van Allen Belts trapped by Earth's magnetic field. But those same Belts are trapped around Earth by the magnetic fields and the deadly radiation is from high-energy cosmic rays smashing into the atmosphere and the resulting particles being trapped.

Even more debatable is whether the magnetic fields stopped/stop atmospheric escape - Venus has no field and lots of air - or whether Mars lost its atmosphere just because it was too small.

 

[Cosmo Novice]

Even more debatable is whether the magnetic fields stopped/stop atmospheric escape - Venus has no field and lots of air - or whether Mars lost its atmosphere just because it was too small.

As I understood it the protection the magnetosphere was mainly due to the magnetic bowshock redirecting solar winds that would otherwise strip our atmosphere away fairly quickly.

This is not debatable as far as I am aware so I will try and dig out some supporting papers - I am fairly certain this is known science.

 

[qraal]

As I understood it the protection the magnetosphere was mainly due to the magnetic bowshock redirecting solar winds that would otherwise strip our atmosphere away fairly quickly.

This is not debatable as far as I am aware so I will try and dig out some supporting papers - I am fairly certain this is known science.

Presently the solar wind strips the atmosphere of Mars away at a few kilograms per second. Earth's loss rate would be even lower. The solar wind was, based on observations of young stars extrapolated to our own, perhaps 1,000 times stronger in the past. Thus the basis of the claim it can strip atmospheres away. But not anymore. Takes billions of years nowadays.

 

[D H]

I think it was Kelvin who said around 1900 something like (my paraphrase): We have now pretty much resolved all the issues in physics, the hard part is done, we are just sorting out some details now...

This supposed quote is a bit off-topic, but since this is a widely-replicated supposed quote, it merits correction. You are talking about a quote along the lines of this one at scienceworld.wolfram.com, "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." That quote was supposedly made in Thomson's 1900 address to the British Association for the Advancement of Science, "Nineteenth Century Clouds over the Dynamical Theory of Heat and Light."

A funny thing about that quote: It's false. You can find the text of the speech here, printed two years after the speech: http://books.google.com/books?id=YvoAAAAAYAAJ&pg=PA363&lpg=PA363#v=onepage&q&f=false.

 

[Cosmo Novice]

Presently the solar wind strips the atmosphere of Mars away at a few kilograms per second. Earth's loss rate would be even lower. The solar wind was, based on observations of young stars extrapolated to our own, perhaps 1,000 times stronger in the past. Thus the basis of the claim it can strip atmospheres away. But not anymore. Takes billions of years nowadays.

Can you please link a supporting article/source, I find this really interesting.

thanks in advance

 

[qraal]

Can you please link a supporting article/source, I find this really interesting.

thanks in advance

Energy balance and momentum of the present solar wind is enough to demonstrate that. But do a Google on the mass loss rate from Mars at present. Alternatively have a look at the NASA ADS and do a fuller search.

 

[Nikitin]

Can increasing the thickness of the atmosphere compensate for lack of a magnetic field?

Yes, it can. Engineering the atmosphere could even stop UVC radiation.

Anyway, not to piss people off again, but much of the solar radiation, except the UV and onwards electromagnetic radiation, reaching Mars is quite harmless isn't it? Electromagnetic radiation with >400nm wavelength and some alpha particles (these ones don't reach Earth due to the magnetosphere).

A few (100?) rads of alpha particles/+ions here and there won't really hurt anyone in an enclosed suit.

 

[Ryan_m_b]

Yes, it can. Engineering the atmosphere could even stop UVC radiation.

Anyway, not to piss people off again, but much of the solar radiation, except the UV and onwards electromagnetic radiation, reaching Mars is quite harmless isn't it? Electromagnetic radiation with >400nm wavelength and some alpha particles (these ones don't reach Earth due to the magnetosphere).

A few (100?) rads of alpha particles/+ions here and there won't really hurt anyone in an enclosed suit.

People were not "pissed off". They were getting frustrated because you were handwaving away very complex, technical and interesting issues that they had taken the time to explain to you (remember no one is under any obligation to do that).

I am unsure about how bad the radiation would be on Mars if there were a thick atmosphere, the atmosphere on Mars would have to be much thicker than that of Earth's to account for the face that Mars has a lower gravity. This means an equal amount of atmosphere would not cause the same pressure obviously necessary for life.

Leading on from this the atmosphere engineering of Mars could have much harder problems to solve, if the atmosphere needs to be 3x thicker to provide the same pressure then we may have problems with the amount of radiation absorbed. In addition martian weather systems could be drastically different from Earth's if the atmosphere was much denser, how this would effect the ecology would have to be carefully considered.

As this goes on more and more I feel that space habitats are a far better option and that to even begin terraforming we are going to need a knowledge of synthetic biology far, far beyond that of today.

 

[Hells]

Why do you have to account for ecology? The only cycle you would have to consider is O2+Cx --> CO2 + H20 --> Cx + O2
On Earth plants are responsible for sequestering Carbon from CO2, but it should be possible to design machines that do the same,
Energy consumption per human: 2200 Kcal = 9 204.8 kJ
Since all the energy comes from oxidation of fuel, we need at least this number of energy to make oxygen. Let's assume that our machine can reverse the reaction with 20% efficiency, the machine will require energy of 46002 kj per human per day to turn CO2 into Cx + O2 to not see a decrease in [O2]. 3600 kJ = 1 kilowatt-hour

The only problem is if our water doesn't condense because there's too low amount of it available, and it will never saturate parts of the atmosphere. Water will be locked in as humidity. A machine can help here as well, by pressuring a part of the atmosphere in a containment vessel.

Terraforming just means making a planet suitable for human habitation, it doesn't mean make it suitable for plant or animal life. Farming could be in sealed domes, with import of specialty nutrients. (bulk water, O2 and CO2 would be available.)

 

[qraal]

Why do you have to account for ecology? The only cycle you would have to consider is O2+Cx --> CO2 + H20 --> Cx + O2
On Earth plants are responsible for sequestering Carbon from CO2, but it should be possible to design machines that do the same,
Energy consumption per human: 2200 Kcal = 9 204.8 kJ
Since all the energy comes from oxidation of fuel, we need at least this number of energy to make oxygen. Let's assume that our machine can reverse the reaction with 20% efficiency, the machine will require energy of 46002 kj per human per day to turn CO2 into Cx + O2 to not see a decrease in [O2]. 3600 kJ = 1 kilowatt-hour

The only problem is if our water doesn't condense because there's too low amount of it available, and it will never saturate parts of the atmosphere. Water will be locked in as humidity. A machine can help here as well, by pressuring a part of the atmosphere in a containment vessel.

Terraforming just means making a planet suitable for human habitation, it doesn't mean make it suitable for plant or animal life. Farming could be in sealed domes, with import of specialty nutrients. (bulk water, O2 and CO2 would be available.)

A good technologist uses the best available technology for the task. Self-replicating bioconverters - i.e. bacteria, archaea, plants and animals - are amazingly more advanced than our current best efforts. Employing very high-power technology for raw conversion of a planet is attractive because it shortens the time-table immensely, but how long does it take to make such a uber-tech system powerful enough?

Paul Birch considered these issues for both Mars and Venus in a duology of papers "Terraforming Mars Quickly" and "Terraforming Venus Quickly". Look them up on "Google" and educate yourselves. The size requirements of the necessary machines is breath-taking and requires a very large in-space economy.

 

[Hells]

1. I am talking about upkeep
2. Haven't we already established that the bioconverters require an ecosystem? That's what we wish to eliminate. We can, for example, use artificial photosynthesis.

 

[D H]

1. I am talking about upkeep
2. Haven't we already established that the bioconverters require an ecosystem? That's what we wish to eliminate. We can, for example, use artificial photosynthesis.

That is a solution in a hand-wavy, science fiction world where perpetually-TRL 1 technology can solve all of the world's problems.

This site is not such a world. We have rules against overly-speculative posts, and this thread has tons of such. Keep it real please, or this thread is locked.

 

[Drakkith]

How can you add an atmosphere of sufficient pressure if the gravity on Mars is only about 1/3 of Earths? Especially once it heats up. Wouldn't much of it disappear?

 

[Nikitin]

No I don't think so. At least not the CO2. The gas needs to get an appropriate escape velocity first.

Though due to the lack of a proper magnetosphere Mars' atmosphere will constantly decay, tho it'l take many millions of years b4 the result is noticeable.

Ryan: I believe the radiation would be somewhere around 2 millirads/day or so on average today for a human on Mars, with the increase coming mostly from + charged ions. I don't think that will hurt anyone once Mars has a proper atmosphere.

I don't think the atmosphere needs to have 3x the molar density than Earth's just because of the lack of gravity.. The pressure equilibrium would obviously arrange itself different from Earth's though and so we'd need some more.

I don't anything about fluid dynamics, so if you read the paper from the NASA physicist which I provided in page 2 you'd see it would be, most likely, doable with just the CO2 reserves in the Martian soil & the dry ice.

 

[qraal]

Yes, it can. Engineering the atmosphere could even stop UVC radiation.

Anyway, not to piss people off again, but much of the solar radiation, except the UV and onwards electromagnetic radiation, reaching Mars is quite harmless isn't it? Electromagnetic radiation with >400nm wavelength and some alpha particles (these ones don't reach Earth due to the magnetosphere).

A few (100?) rads of alpha particles/+ions here and there won't really hurt anyone in an enclosed suit.

The solar wind gets mostly deflected around the present day Martian and Venusian atmospheres via their ionospheres, the charges being enough to deflect much of the wind around the planets. A bit of atmosphere is stripped away - the total having been measured by Mars Express as a couple of kilograms a second - but nowhere near enough to strip the atmosphere away in less than aeons. The radiation that reaches the surface that is of concern during solar flares is from x-rays. Cosmic-rays are significantly higher, but no more so than what is encountered on the ISS. On Earth they run into gas molecules much higher up and their secondary radiation has mostly decayed into muons by the time it reaches the surface.

 

[qraal]

How can you add an atmosphere of sufficient pressure if the gravity on Mars is only about 1/3 of Earths? Especially once it heats up. Wouldn't much of it disappear?

No. The escape velocity at the exosphere is sufficiently high for even a warm atmosphere to be retained indefinitely. Especially if it remains mostly carbon dioxide, which reduces the exosphere's temperature thanks to more efficient IR emission.

 

[qraal]

I don't think the atmosphere needs to have 3x the molar density than Earth's just because of the lack of gravity.. The pressure equilibrium would obviously arrange itself different from Earth's though and so we'd need some more.

The column mass has to be higher, but the molar density can be whatever so long the total mass is enough to provide the surface pressure by its weight.

 

[Ryan_m_b]

Why do you have to account for ecology? The only cycle you would have to consider is O2+Cx --> CO2 + H20 --> Cx + O2
On Earth plants are responsible for sequestering Carbon from CO2, but it should be possible to design machines that do the same,
Energy consumption per human: 2200 Kcal = 9 204.8 kJ
Since all the energy comes from oxidation of fuel, we need at least this number of energy to make oxygen. Let's assume that our machine can reverse the reaction with 20% efficiency, the machine will require energy of 46002 kj per human per day to turn CO2 into Cx + O2 to not see a decrease in [O2]. 3600 kJ = 1 kilowatt-hour

The only problem is if our water doesn't condense because there's too low amount of it available, and it will never saturate parts of the atmosphere. Water will be locked in as humidity. A machine can help here as well, by pressuring a part of the atmosphere in a containment vessel.

Terraforming just means making a planet suitable for human habitation, it doesn't mean make it suitable for plant or animal life. Farming could be in sealed domes, with import of specialty nutrients. (bulk water, O2 and CO2 would be available.)

Ok this thread is starting to go off of the rails. There have been many posts explaining why an ecology is necessary for life. Hand-waving "if we had a machine" is not useful. You've also not considered the necessity for an ecology to sustain farming, provide the 1kg of gut flora humans need to survive etc etc

 

[Nikitin]

The column mass has to be higher, but the molar density can be whatever so long the total mass is enough to provide the surface pressure by its weight.

Yes, you are right, heavier gases will obviously concentrate themselves on the surface, though still, having increased molar density will be a must once the makeup of the Martian atmosphere is getting engineered to be similar to that of Earth.

Anyway, to the main point, CO2 is quite a heavy gas, and there are most likely sufficient quantities of it on Mars.

As for your second post, good to know that the radiation isn't too bad on Mars, except during Solar flares. Unfortunately I have no clue about Muons, haven't had about them in class yet.

 

[Ryan_m_b]

The column mass has to be higher, but the molar density can be whatever so long the total mass is enough to provide the surface pressure by its weight.

What effect would a different molar density have on life though? These are incredibly fine systems, slight changes could have catastrophic effects on the environment.

 

[Nikitin]

Well, would a high concentration of CO2 in the air really be harmful for the photosynthesis-organisms (and the organisms they need to survive, if they need any)?

Anyway, I don't think the molar density of the air close to the surface of a completely terraformed Mars would be particularly higher than on earth.

Though in the outer layers of the (completely terraformed) Martian atmosphere I'd think the molar density would be significantly higher than in the outer layers of Earth's atmosphere.

 

[Ryan_m_b]

Anyway, I don't think the molar density of the air close to the surface of a completely terraformed Mars would be particularly higher than on earth.

Though in the outer layers of the (completely terraformed) Martian atmosphere I'd think the molar density would be significantly higher than in the outer layers of Earth's atmosphere.

What makes you think the density on the ground could be the same as Earth but the density in the outer layers could be higher?

 

[Nirgal]

You should read the Red Mars Trilogy by Kim Stanley Robinson (Red Mars, Green Mars, Blue Mars). This is in my opinion one of the best science fiction series that has ever been written about colonizing another planet. The story revolves around the science and engineering involved with regards to the application of terraforming Mars, creating a new government, the relationship to Mars and Earth, and the psychological and sociological aspects of living on a different planet and trying to survive. Excellent excellent excellent.

 

[D H]

Nirgal, perhaps you should start reading something a bit more reliable than science fiction. Robinson's Mar's Trilogy revolves around Robinson's politics. Everything else, the bad plot, the bad characters, and the bad science, takes second shrift to this barely-disguised socialist diatribe.

 

[Nirgal]

Nirgal, perhaps you should start reading something a bit more reliable than science fiction. Robinson's Mar's Trilogy revolves around Robinson's politics. Everything else, the bad plot, the bad characters, and the bad science, takes second shrift to this barely-disguised socialist diatribe.

Ah, I see you don't enjoy that novel because of your own politics. I tend not to judge fiction based on my disagreements with what occurs in the story. Considering that the book won Hugo, Clark, Locus, and Nebula awards, I would suggest that your opinions do not reflect that of the majority.

What would you have me read?