Author Topic: Mars Terraforming discussion  (Read 57481 times)

Offline sanman

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Re: Mars Terraforming discussion
« Reply #20 on: 01/07/2014 10:07 pm »
"oscillating" = oxidizing ??

Were you talking about somehow modifying the CO2 atmosphere to make it an O2 atmosphere?

Even if you could get 1 Earth Atm of O2 atmosphere, that could still be deadly / unhealthy for humans.

Remember, here on Earth our atmosphere is 79% N2, 21% O2


Current Mars atmosphere only has 1-2% traces of Nitrogen gas. It's not clear whether there are any significant underground deposits of nitrogen, or what form they'd take.

I think it would be cool if we could grab ammonia chunks from Saturn's rings and then rain them down upon Mars, to bring more nitrogen. Or maybe we could grab ammonia from farther out in the Kuiper belt, or even opportunistically deflect passing comets.



Offline Robotbeat

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Re: Mars Terraforming discussion
« Reply #21 on: 01/07/2014 10:37 pm »
Humans can survive quite well, thank you, on less than Sea Level partial pressure of oxygen. And the atmosphere doesn't need to be Earth pressure, 1psi is good enough (1psi of pure oxygen is enough for human survival, though 2psi is much more comfortable... and pure oxygen isn't a threat if the partial pressure is a little lower than Earth ambient).

But I sincerely doubt Mars will have an oxygen-rich atmosphere anytime soon. Too much stuff to oxidize. The humans can just get masks. Or put oxygen right into the bloodstream using artificial organs similar to Type 1 (child-onset, insulin-dependent) diabetics with insulin pumps. I mean, artificial organs for oxygenating the blood seem like much less of a stretch than terraforming Mars, especially with an oxygen-rich atmosphere.
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Offline Andrew_W

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Re: Mars Terraforming discussion
« Reply #22 on: 01/07/2014 10:56 pm »
I'm going for oscillation = libration = liberation.  :)

People often don't realize just how short on atmospheric volatiles Mars is. If you were to take the entire Martian atmosphere and stuff it into a big crater (Hellas) you still wouldn't get over 50 kPa of pressure at the bottom.

Chris, what's the best source of info you know of on how much atmosphere is available with heating? I've seen people claiming "30kPa of volatiles" I figure which I suppose includes water.



« Last Edit: 01/07/2014 11:02 pm by Andrew_W »
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Offline Robotbeat

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Re: Mars Terraforming discussion
« Reply #23 on: 01/07/2014 11:06 pm »
I'm going for oscillation = libration = liberation.  :)

People often don't realize just how short on atmospheric volatiles Mars is. If you were to take the entire Martian atmosphere and stuff it into a big crater (Hellas) you still wouldn't get over 50 kPa of pressure at the bottom.
...
Now THERE'S an idea...

...as far as my quote on volatiles... I've looked at rough estimates of size of the glaciers and found there should be enough volatiles spread over the planet to get 1psi at the bottom of Hellas Basin (and to other places, 0.75psi, etc...).
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Offline Solman

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Re: Mars Terraforming discussion
« Reply #24 on: 01/08/2014 01:32 am »
I remember seeing Chris McKay talking about terraforming by slamming an asteroid into one of the poles a few years back.
Might be a fast and economical way to to it.

Offline Robotbeat

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Re: Mars Terraforming discussion
« Reply #25 on: 01/08/2014 01:50 am »
I remember seeing Chris McKay talking about terraforming by slamming an asteroid into one of the poles a few years back.
Might be a fast and economical way to to it.
Indeed! Probably even cheaper than the carbon black and super greenhouse gases. More dangerous, though.

...and I'd use a really big comet instead, if there were one available on the right trajectory.

Just imagine if we had had forty years of prior notice (and a powerful deep space exploration capability... Say on the level of manned Titan surface missions) for that one comet that's supposed to swing close by Mars. (And if the comet was bigger...) We may be able to increase the surface pressure to outside-livable in just a few decades.
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Offline sanman

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Re: Mars Terraforming discussion
« Reply #26 on: 01/08/2014 10:51 pm »
Comet thing sounds like a good idea, but you guys are only talking about overall pressure, whereas I was talking about atmospheric composition. We don't know what the longer terms effects are of living in an atmosphere lacking the large nitrogen component. It's possible that out bodies might degrade without it, since nitrogen is a key part of our metabolism. The O2 partial pressure may not be enough.

I'm also wondering if we could find some large ammonia bodies in the asteroid belt, to toss at Mars.

Offline gbaikie

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Re: Mars Terraforming discussion
« Reply #27 on: 01/08/2014 11:56 pm »
I remember seeing Chris McKay talking about terraforming by slamming an asteroid into one of the poles a few years back.
Might be a fast and economical way to to it.

And economical way to mine space rocks. Use planet to reduce the delta-v, though have impact around say
5 km/sec, so more like large explosion rather than a nuclear strike. Also have them about 20 meter diameter, so atmosphere slows it down by small amount. Most rocks 20 meter won't reach Earth surface at high velocity,
though they would impact at high velocity on Mars- so maybe Mars atmosphere causes a 20 meter diameter rock to lose 1 to 2 km/sec.
And for moving them to intersect Mars, a small nukes could be used to change their orbits.

Offline colbourne

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Re: Mars Terraforming discussion
« Reply #28 on: 01/09/2014 02:21 am »
We have the perfect comet which is due to skim past Mars this year.  Possibly firing a very powerful laser at it would be enough to divert its course enough to hit.

Offline Robotbeat

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Re: Mars Terraforming discussion
« Reply #29 on: 01/09/2014 04:06 am »
Comet thing sounds like a good idea, but you guys are only talking about overall pressure, whereas I was talking about atmospheric composition. We don't know what the longer terms effects are of living in an atmosphere lacking the large nitrogen component. It's possible that out bodies might degrade without it, since nitrogen is a key part of our metabolism. The O2 partial pressure may not be enough.

I'm also wondering if we could find some large ammonia bodies in the asteroid belt, to toss at Mars.
I'm aware of absolutely no scientific finding that suggests humans need nitrogen in the air to live. Our bodies get fixed nitrogen through our diet.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Lobo

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Re: Mars Terraforming discussion
« Reply #30 on: 01/09/2014 05:17 am »
In this same vein, I've always thought that Titan would be much easier to colonize...if it weren't so darn far away.   Maybe if there's a next leap in propulsion or something. 
But Titan just has a lot to like.   A nice thick atmosphere for aerocapture and terrestrial scale parachutes.  Pressure suits would not be needed, just basically a scuba type system.  A magnetosphere from Saturn to protect it. etc.

If Saturn and Titan were say where Mars is (setting aside how that might effect Earth's Orbit), Perhaps Titan could almost be like Pandora from "Avatar" in that, you might just need a respirator mask, and a light thermal suit.  Titan's atmosphere is almost all nitrogen, so I'd think if you had a respirator that could take in atmospheric air, filter out all of the hydrocarbons, and then add some oxygen to it before breathing it.
You could still do that where Titan actually is, but the temperatures are so cold, that you'd need more comprehensive environmental suits (although not pressurized), and no exposed skin obviously, so probably a full helmet.  Maybe heating elements in the suit if it couldn't be insulated enough.  Still, probably a promise of more "freedom" for colonization than on Mars I'd think.  Need a faster way to get there than we have now though. 

Offline Andrew_W

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Re: Mars Terraforming discussion
« Reply #31 on: 01/09/2014 06:26 am »
Titan's way too cold, the heating bill would be enormous, and the Suns too faint, and hidden, to be of much use. Anything you built, especially the nuclear power station, would have to be well above the ground to stop it melting it's way to the middle of the moon - like having The China Syndrome with the plant still intact.
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Offline Lars_J

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Re: Mars Terraforming discussion
« Reply #32 on: 01/09/2014 07:01 am »
In this same vein, I've always thought that Titan would be much easier to colonize...if it weren't so darn far away.   Maybe if there's a next leap in propulsion or something. 
But Titan just has a lot to like.   A nice thick atmosphere for aerocapture and terrestrial scale parachutes.  Pressure suits would not be needed, just basically a scuba type system.  A magnetosphere from Saturn to protect it. etc.

I think Ganymede might be the best place to colonize in the solar system.
 - Only moon with its own magnetic field (weak but still)
 - absolutely loaded with volatiles and water (+ metals), a treasure trove for mining
 - larger than mercury, but lower gravity than the moon (1/7th G)
« Last Edit: 01/09/2014 07:07 am by Lars_J »

Offline Oli

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Re: Mars Terraforming discussion
« Reply #33 on: 01/09/2014 08:35 am »

Low gravity is a problem.

I still think the easiest way to establish a "colony" would be an artifical gravity station located near asteroids for supplies.

Offline gbaikie

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Re: Mars Terraforming discussion
« Reply #34 on: 01/09/2014 01:52 pm »
In this same vein, I've always thought that Titan would be much easier to colonize...if it weren't so darn far away.   Maybe if there's a next leap in propulsion or something. 
New Horizon spacecraft launch from Earth with sun escape velocity:
"New Horizons is a space probe launched by NASA on 19 January 2006 to study the dwarf planet Pluto ....
it flew by the orbit of Mars on 7 April 2006, Jupiter on 28 February 2007, the orbit of Saturn on 8 June 2008; and the orbit of Uranus on 18 March 2011"
http://en.wikipedia.org/wiki/New_Horizons

So from Earth it took it 2 1/2 year to get to Saturn orbit.
If same New Horizon launch vehicle had launched instead from planet Mercury instead of Earth, it could got to Saturn in less than 1/2 the time.
Due to number of reasons.

One reason is from planet Mercury, there is lower sun escape velocity needed than compared to Earth.
But this is not only reason. But I will go over this.
So let look three sun escape of Earth, Mercury, and Mars. Wiki:
Earth: 42.1 km/sec
Mars: 34.1 km/sec
Mercury: 67.7 km/sec
Earth has orbital velocity of:
"Mean orbital velocity (km/s)     29.78       
Max. orbital velocity (km/s)     30.29
Min. orbital velocity (km/s)     29.29"
So to reach Earth escape, one adds earth's orbital vehicle to delta-v of rocket. 42.1 minus 30 is 12.1.
So one needs 12.1 km/sec of delta-v added to Earth's orbital velocity.
Mars has orbital velocity of:
Mean orbital velocity (km/s):  24.13
Max. orbital velocity (km/s):  26.50
Min. orbital velocity (km/s) : 21.97
So Mars solar escape is 34.1 km/sec, minus 26 or 8.1 km/sec of delta-v needed.

Mercury has orbital velocity of:
Mean orbital velocity (km/s): 47.87
Max. orbital velocity (km/s): 58.98
Min. orbital velocity (km/s) : 38.86
So Mercury solar escape is 67.7 km/sec, minus 58 or 9.7 km/sec of delta-v needed.
In order, delta-v needed is 12.1 km/sec {Earth}, 8.1 km/sec {Mars}, and 9.7 km/sec {Mercury}.
So Mars has lowest velocity needed to do sun escape, and it's nearer in distance to Saturn [or
Jupiter], but with sun escape velocity, one get to Saturn [or Jupiter] faster from Mercury as compared
to Mars or Earth.
New Horizon left Earth on 19 January 2006 and "flew by the orbit of Mars on 7 April 2006". So in 78 days
it travel from Earth distance to Mars distance.
This rock:
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007%20PR25;orb=1
Went from Mercury distance to Earth distance, starting March 15 2013 at Mercury and going to Earth distance on April 25. So 41 days. Then traveled to Mars distance on June 2 2013. So another 38 days.
In total it took 79 days from Mercury to Mars. But this rock has velocity of less that sun escape.
So with sun escape from Mercury not only would get Jupiter quicker than from Earth escape, but cross Mars
orbit, quicker than from Earth sun escape.

Next we look difference: Earth needs 12.1 km/sec delta-v added. Mercury needs 9.7 km/sec.
If use same rocket at Mercury, than 12.1 minus 9.7 is 2.4 km/sec "extra". Or can add 2.4 to the escape velocity, thereby going faster the Mercury sun escape.
What does this mean?
Well if look at the space rock as goes out from Mercury it's slowing down as reaches Earth and Mars distance. With Mercury Sun escape velocity, it slows down less than what this rock does. And with velocity
over sun escape, it slows down less than the sun escape.
And added velocity has greater effect the further you get from the sun.
Just guessing, but compared rock getting to Earth distance from Mercury, if going sun escape, instead of 41 days, it could be say, +30 days [or save 10 days] but difference time to Mars would greater, instead 38 days, could closer to 2 weeks [save 14 days]. But such shorten of time is more dramatic at Saturn or Jupiter distance, when go slightly above Mercury escape velocity.
So we difference of 2.4 km/sec, or 2.4 km above Mercury sun escape.
Another factor is leaving earth one gets gravity losses. So Mercury has lower gravity and no atmosphere.
Or with Earth one lose about 2 km/sec leaving Earth. Leaving Mercury with such rocket would have number
near zero. In addition the rocket engine performs better in vacuum. Or rocket that gets 10 km/sec leaving Earth get more if rocket engines are functioning in vacuum.
We are not even including the changes one do to the rocket's design so performs better. In other words
we using rocket designed for launching from Earth, and same rocket on Mercury. That rocket will simply perform a lot better launched from Mercury.
Let's go into the weeds a bit:
Altas V First Stage:
Thrust at Sea Level    3,827kN
Thrust (Vacuum)    4,152kN
http://www.spaceflight101.com/atlas-v-401.html
So 10% more thrust in vacuum.
Or in terms of ISP:
"Thrust at Sea Level, 3,827kN. Isp SL, 311s. Thrust (Vacuum), 4,152kN (933,369 lbf). Isp Vac, 338s"
And a launch of rocket would "look" very different. It's starting thrust instead being say 150% of the weight of rocket. So on earth 1000 ton rocket has 1500 tons of thrust. On Mercury the it's 333 tons and more 1500 tons of thrust. So it jumps off the launch pad. It would be very dissimilar looking than the Earth
rocket launch.
Plus there are "details" such as from Oberth effect.
But one is added about 6 km/sec above Mercury sun escape by rocket not designed to function from
Mercury.

Edit: So said Mercury sun escape get to Saturn less than 1/2 time of Earth sun escape. I thought
provide rough answer of how much it is less than 1/2 of the time. And I use the Cassini spacecraft to illustrate it. It should noted that Cassini would be slower than Mercury sun escape trajectory. But gets to Saturn edit: Jupiter [and Mars orbital distance] faster than New Horizon earth escape.
So we start from point Cassini crosses Earth orbital distance [it's on way to Saturn, after spend time in inner system getting gravity assist, and gets last gravity assist off Earth, on August 18th 1999, and then 39 days later cross Mars orbit [September 26 1999]. Mercury sun escape would do this in about 1/2 the time, but it's about twice as fast as New Horizon.
Then going past Mars, Cassini goes to Jupiter [where does another gravity assist], and crosses Jupiter
on 2001 Jan 5. So about 6 months from Earth to Jupiter. And Mercury sun escape would same distant is
less than 3 months. Or from beginning at Mercury distance [rather crossing Earth] less than 4 months
to Jupiter distance.
Screen shot of simulator of Cassini, 2001 Jan 5:
http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=-82&vbody=1001&month=1&day=5&year=2001&hour=00&minute=00&rfov=60&fovmul=-1&bfov=20&porbs=1&showsc=1&showac=1
Or go here put in what you want:
http://space.jpl.nasa.gov/
And take until 2004 June 26 to cross Saturn's outer moon, Iapetus.
And 4 days later to cross Titan's orbital distance. And a day later to cross closest to Saturn.
Or  2004 July 1 to cross Saturn's orbit.
So Cassini gets to Jupiter pretty quick, but enter Saturn orbit it requires a lot more time, and not
just because Saturn's distance.
Cassini gets to Juptier twice as fast at New Horizon "New Horizons received a Jupiter gravity assist with a closest approach at 05:43:40 UTC on 28 February 2007 when it was 2.3 million kilometres (1.4 million miles) from the planet." -wiki. Or slightly over year.
But flew by Saturn's orbital distance on June 10 2008. From Jupiter arrived much faster to Saturn distance.

Or from Mercury sun escape [or faster] you get to Jupiter in less than 4 months, and flyby Saturn in less than 4 month, but if land on Titan, the leg from Jupiter should be slower [and/or less straight] . Which can do with gravity assist using Jupiter. And/or braking at Saturn, atmospheric braking of Saturn and/or Titan moon.
And same applies if want go to say Jupiter's moon Europa. Or getting to Europa from Mercury in less than 4 month would be somewhat hard, and involve gravity assist with say Earth, and/or aerobraking with Jupiter.  Of course Jupiter is wonderful for gravity assists.
Or from Mercury you don't need gravity assists to get out to outer planets, but to land or go into orbit they are more or less required.
« Last Edit: 01/09/2014 04:13 pm by gbaikie »

Offline R7

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Re: Mars Terraforming discussion
« Reply #35 on: 01/09/2014 02:10 pm »
Say you managed to melt the Martian glaciers, smeared it with carbon or something to heat it up and got the atmosphere as thick as possible. How long would it last? Wouldn't it "leak" into space much faster than it does now?
AD·ASTRA·ASTRORVM·GRATIA

Offline sanman

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Re: Mars Terraforming discussion
« Reply #36 on: 01/09/2014 02:14 pm »
I'm aware of absolutely no scientific finding that suggests humans need nitrogen in the air to live. Our bodies get fixed nitrogen through our diet.

I don't think it's really been researched. Yes, our bodies get nitrogen through protein, but who's to say it wouldn't get leeched out from a non-nitrogen atmosphere. We've evolved in this atmosphere, and I don't recommend living long-term in something different from this atmosphere - because otherwise, you're a human guinea pig who may end up finding out unpleasant things the hard way.
« Last Edit: 01/09/2014 02:15 pm by sanman »

Offline douglas100

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Re: Mars Terraforming discussion
« Reply #37 on: 01/09/2014 02:20 pm »

...In this same vein, I've always thought that Titan would be much easier to colonize...if it weren't so darn far
If Saturn and Titan were say where Mars is (setting aside how that might effect Earth's Orbit), Perhaps Titan could almost be like Pandora from "Avatar" in that, you might just need a respirator mask, and a light thermal suit.  Titan's atmosphere is almost all nitrogen, so I'd think if you had a respirator that could take in atmospheric air, filter out all of the hydrocarbons, and then add some oxygen to it before breathing it...

If you put Titan at Mars' distance from the sun it would lose its dense atmosphere quickly (in the timescale of the life of the Solar System.) Titan can only hold such a massive atmosphere with such a low gravity because of its extremely low temperature. Which means if you wanted a planet with a more massive atmosphere at Mars' orbit you would need a more massive planet.
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Offline alex_chris

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Re: Mars Terraforming discussion
« Reply #38 on: 01/09/2014 03:02 pm »
If this thread is purely Martian atmosphere focused, these are my 2 cents:

Current Martian atmoshpere is on average (it various) 0.6kPa, 96% of which is in the form of CO2, 2.1% is Argon and 1.9% is nitrogen and then there are some trace gases.

Just as a comparison, the Earth's atmoshpere is on average 101kPa, of which 21% is O2, 78% is nitrogen, 0.9% is argon and 0.04% is CO2.

Pressure:

Regardless of what gases you add to the Martian atmoshpere, a key thing for human survivability is atmospheric pressure. We need pressure suits to withstand environments with too low pressure. One of the three key metrics therefore is, whether you can get pressure high enough to allow for a non-pressurized suit environment. For humans, the key survivable limit of pressure is the Armstrong limit or 6.3kPa. At that level of pressure water boils, which kills a human being. This means the atmosphere needs to be severely thickened.

Sublimating the CO2 ice at the Martian poles and part of the survice CO2 ice could result in an increase from 0.6kPa to over 20kPa, most of it would be CO2, some estimates even state 30kPa, which would be comparable to an altitude of 9,000m (slightly above Mount Everest). While not comfortable, this pressure level could be enough for work using non-pressurized suits or even just oxygen masks to work provided the person is healthy and adjusted for work in such environment.

Temperature:

Increasing pressure won't do us any good, if a 30kPa environment still involves current temperatures at Mars. The good thing is, melting the Martian CO2 ice is always related to also increasing the average temperature. It currently is 55 degrees C below 0 with large fluctuations from -150 degrees C to above 0. Fluctuations would be smoothened out by an increased CO2 atmoshpere and the overall temperature would likely increase significantly, but nowhere near Earth's average 13 degrees C. The most viable method of heating up Mars I have read about are plants that put out flurine composits on Mars. Such gases, such as CFCs, have a warming factor several thousand times the one of CO2 (CF3SCF3, CF3OCF2OCF3, CF3SCF2SCF3, CF3OCF2NFCF3, C12F27N) and could over a period of decades warm up Mars significantly. We are also not talking about utopian quantities of fluorine composits, but only several times the amounts put into the Earth's atmosphere from the 70s to the early 90s (when they were banned). This could also be used as a first step to warm the Martian atmosphere enough to release a large part of the CO2 ice, using the positive forcing of CO2 global warming on Mars to further gain temperature and pressure.

Atmospheric composition

Even if you are able to increase average temperatures on Mars significantly and add all the CO2 ice, you end up with a somewhat cold, 30kPa 99% CO2 atmosphere. I believe the question was whether you could convert the CO2 into an O2 atmoshpere. The best way to start that is probably using some genetically manipulated live forms that use up CO2 and emit O2. But that would take quite some time. The current Marsian atmoshpere weights 25 teratons and at 30kPa it would weight above 1000 teratons. Even if 2/3rds of the Martian soil would be covered with genetically manipulated phytoplankton or other organism, that each km˛ needs to convert 10 million tons of CO2 (1000 teratons = 1000 trillion tons of CO2, 2/3rds of Mars equals 100 million km˛). Or 1m˛ of organism needs to filter 10 tons of CO2. That takes some time. A square meter of organism can only convert a few grams of CO2 per day, if not less. So we are talking hundreds, if not thousands of years.

The best way to move forward quickly next to genetically modified organism converting the CO2 is some type of machinery. This presumes we have the required energy resources to do so.

But even if we convert most or all CO2 to O2, as mentioned above, the N2 is missing. You need a puffer gas for a stable atmosphere and N2 just isn't there and it is unclear how much is in the Martian crust or whether it could be extracted if there are large deposits. This is probably the biggest practicle obstacle for terraforming of the Martian atmosphere. You probably need to bring in external nitrogen, likely in the form of ammonia from asteroids. The "good" thing would be that you need to do that anyway to get some water ice in. If you find some ammonia you probably also find some water ice objects at the same time. In any event, getting them to Mars is pure sci-fi.

To sum up, I believe it's feasible to increase the temperature of Mars and the pressure. Not sure if that is enough for anyone to move to Mars though...


Offline RanulfC

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Re: Mars Terraforming discussion
« Reply #39 on: 01/09/2014 06:40 pm »
I'm aware of absolutely no scientific finding that suggests humans need nitrogen in the air to live. Our bodies get fixed nitrogen through our diet.

I don't think it's really been researched. Yes, our bodies get nitrogen through protein, but who's to say it wouldn't get leeched out from a non-nitrogen atmosphere. We've evolved in this atmosphere, and I don't recommend living long-term in something different from this atmosphere - because otherwise, you're a human guinea pig who may end up finding out unpleasant things the hard way.

Actually I'm pretty sure it HAS been extensivly researched :) We've had people living in pure oxygen envirionments for months at a time since the 1920s IIRC. I KNOW the US and Russians researched pure O2 closed environments during the space race, at partial pressures and full pressures. The biggest downside to a pure O2 atmosphere is that pretty much everything burns unders those conditons if it gets ignited.

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From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

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