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But, even if we have to wear O2 masks, an Atmosphere still offers Aerobraking, shirt-sleeves, warmth, heat circulation...
Humans can tolerate around 100 mb of CO2, apparantly up to 120 mb, which has a molecular weight of 40-something (either 42 or 48), so that could be used as a buffer gas. If we're aiming for a 650 mb atmosphere (the minimum humans can tolerate over an extended period of time), that gives us 15-20% of the atmosphere. If half of the atmosphere is O2, that's about 70% already. Use Argon, Nitrogen, and Helium (scavenged from the solar wind) for the rest, you've got the atmosphere done.
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I do not believe we can tolerate that much CO2.
Here's from Wikipedia:
http://en.wikipedia.org/wiki/Carbon_dioxide#Toxicity
"It is dangerous when inhaled in high concentrations (greater than 5% by volume, or 50,000 ppm). The current threshold limit value (TLV) or maximum level that is considered safe for healthy adults for an eight-hour work day is 0.5% (5,000 ppm). The maximum safe level for infants, children, the elderly and individuals with cardio-pulmonary health issues is significantly less.
"Concentrations higher than 1,000 ppm (0.1%) will cause discomfort in more than 20% of occupants, and the discomfort will increase with increasing CO2 concentration. The discomfort will be caused by various gases coming from human respiration and perspiration, and not by CO2 itself. At 2,000 ppm (0.2%) the majority of occupants will feel a significant degree of discomfort, and many will develop nausea and headaches.
Also remember that O2 levels have to be kept below 30% or so to reduce flammability.
Given those two factors, we'd still need 70% of the atmosphere from some other source.
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Well, that's from Wikipedia, the most unreliable source on the net. Whan planning a mission, do you really think people would rely on Wikipedia?
I should have pointed out people can get acclimatized to it. It's actually 5% that people start to get uncomfortable. Check out this post. 5%=50 mb. If we're aiming for a 650 mb atmosphere, that's 1/13 of the atmosphere. Half of the atmosphere would be 325 mb, below the combustion limit of 350 mb.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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Well, that's from Wikipedia, the most unreliable source on the net. Whan planning a mission, do you really think people would rely on Wikipedia?
I should have pointed out people can get acclimatized to it. It's actually 5% that people start to get uncomfortable. Check out this post. 5%=50 mb. If we're aiming for a 650 mb atmosphere, that's 1/13 of the atmosphere. Half of the atmosphere would be 325 mb, below the combustion limit of 350 mb.
Human beings can survive quite well in a pure oxygen atmosphere, for indefinite periods. A partial pressure of 300mbar O2 will produce the same O2 concentration in our blood as sea-level pressure air. You do not need to flood the atmosphere with excessive CO2 or Xenon or anything else. The partial pressure of water vapour will generally be higher in an a lower pressure atmosphere and it will provide some buffer gas effects.
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But, what about the effects of the lower pressure?
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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Well, that's from Wikipedia, the most unreliable source on the net.
And then you go on, and cite a *New Mars thread* as contradicting evidence?
You have the *gall* to dismiss Wikipedia and then suggest I should listen to anonymous posters on a New Mars thread?
Get some *real* sources before you try to ridicule Wikipedia. Your source as it currently stands is *far* more unreliable than Wikipedia was even three years ago.
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The stuff on Wikipedia *is* posted by Anonymous people. I'd rather trust the people on this forum, as they are more reliable.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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More reliable than a source that is continuously fact-checked and fixed by thousands of people?
Right, keep living in your cloud castle.
Wikipedia is dozens of times more reliable than any non peer reviewed message board can ever dream to be. When it's been scientifically verified to be on the same order of accuracy as the damn Encyclopedia Britannica, I think slandering its accuracy isn't going to gain you any points.
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Where are you getting the 650 mb lower limit, terraformer? The lowest is around 500 mb. I suggest 650 as the lowest where people don't have any problems. That said, I would suggest an atmos. 550mb, 275 O2, 50 CO2, 15 H2O, 10 Ar, 100 N2, 100 He. We are going up against what can really be done, so I think people can live with this atmosphere.
-Josh
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That would wok, though I think it would be better to use more Ar and less N2. Argon is more available on the Moon - search 'Lunar Atmosphere' - whereas N2 isn't.
People don't explode on top of Everest, which is above 67 % of Earths atmos., which gives us 330 mb safe pressure, so an O2/CO2 atmos. would be fine.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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Well, that's from Wikipedia, the most unreliable source on the net.
And then you go on, and cite a *New Mars thread* as contradicting evidence?
You have the *gall* to dismiss Wikipedia and then suggest I should listen to anonymous posters on a New Mars thread?
Get some *real* sources before you try to ridicule Wikipedia. Your source as it currently stands is *far* more unreliable than Wikipedia was even three years ago.
Can I assume that you're referring to my post on finding a limit to CO2 tolerance? If so, I can provide you references to the 40+ peer-reviewed papers that I researched when coming up with the 120 mbar value. As an example, the papers came from such publications as The American College of Chest Physicians, The Journal of Applied Physiology, European Neurology, The American Society for Clinical Investigation, The American Physiological Society, Aerospace Medicine, and many other reputable sources.
You are absolutely correct in questioning source veracity, and I would be happy to answer any concerns you have over my estimate, if I am correct in interpreting that is the issue at hand.
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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Please post them here.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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Please post them here.
I have appended them to my original post, here, which I think is the logical thing to do.
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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That would wok, though I think it would be better to use more Ar and less N2. Argon is more available on the Moon - search 'Lunar Atmosphere' - whereas N2 isn't.
People don't explode on top of Everest, which is above 67 % of Earths atmos., which gives us 330 mb safe pressure, so an O2/CO2 atmos. would be fine.
The lunar atmosphere is essentially nonexistent. there is less then 10,000 kilograms of air in the whole atmosphere.
Nitrogen is rare, but it can be bound up in compounds. And nitrogen is necessary for life.
-Josh
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But not in the sort of quantities we have on Earth.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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We don't need anywhere near 79% Nitrogen for plants to fix it. Only a tiny fraction of the atmosphere (5 mb according to the Minimal Martian Terraformed atmospheres thread) needs to be Nitrogen.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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but it would be good for everyone to have more. On another note, ifwe have truly rediculous quantities of uranium, we could make the atmosphere partly UF4, which would nearly never leave.
-Josh
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I wonder whether you ever want to actually breathe on the Moon Post-terraformation.
How would it be *good* or everyone to have more N2? It wouldn't do them any harm, but it would do them any good, either. It seems most people seem to think Terraforming means 1 full bar of atmosphere.
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At 5 mb of nitrogen, plants begin to fix it. but there still isn't enough to go around, I would guess. For The Moon, the more nitrogen the better. Because we could never hope to get 780 mb of nitrogen, I went for 100 because it's a round number, and because it seemed like there would be a decent amount of nitrogen to go around. Remember, every protien in your body has nitrogen in it. And terraforming means getting as close to earth conditions as physicaly possible. So an ideally terraformed body would be an exact copy of earth. We come as close to that as possible. Of course, considering reality, we could only do so much.
-Josh
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I think that Xenon atmosphere is a great idea.
Not in a terraforming sense. Moon is too small to retain a breathable atmosphere. But a dense atmosphere would make Moon easier to colonize.
The atmosphere is a good shield for small meteorites. Allow to transfer heat from the cool side to the hot side of Moon. Machines work better with air because heat could be dissipated throught convection or conduction plus always existent radiation.
Domes will be a lot more secure if the pressure is near or the same inside and outside it. Leaks of air will be reduced too (even more if outside is at more pressure that inside, because the air push into). Because xenon is not toxic, possible leaks are not critical if enough oxigen is retained inside the dome.
Without atmosphere, transparent and slight domes are too much difficult and we will use underground colonies the first times. But this colonies are closed boring places, and far less attractive to live in.
Where xenon could be taken? Well, make an atmosphere, like terraforming, is always a long time task.
Xenon is probably almost always in form of gas, so probably we could not found it in enough amount outside planets. So, or we collected from gigant planets (very deep in atmosphere, so really hard to recover it) or we found it on unpredictable places, or it will not be enough xenon to make this artificial atmosphere.
Another possibility could be make xenon artificially through transmutation of iodine with neutron radiation that I hope could be easily created with fusion reactors were became available.
Although iodine is a rare element too, because is found in compounds, exists a greater probability to found enough large deposits in some place of the solar system in solid forms, perhaps on the meteorites of the asteriod belt, that is very much easy to catch that extract from a gigant planet.
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Hi Spaniard, welcome to New Mars.
I agree that giving the moon an atmosphere is a good idea.
You have some interesting thoughts on sources of xenon. Although iodine is rare, yours is the first proposal I've heard that could possibly generate the required amount of xenon.
Transmutation is fairly energy intensive though. It might be more practical to have an oxygen-based atmosphere and just use that energy to replace any losses, say by splitting water from Ceres.
Fan of [url=http://www.red-oasis.com/]Red Oasis[/url]
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Hi Spaniard, welcome to New Mars.
Thanks.
Transmutation is fairly energy intensive though.
I know but this is the great part of this.
Xenon could be generated as a byproduct of neutronic fusion like deuterium-deuterium fusion.
Neutronic fusion require some materials shielding the reactor. If we used compounds that contains iodine, it will be converted into xenon.
Creating xenon would not consume energy. Xenon would became a free gift from using neutronic fusion.
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So, for a partly-terraformed Lunar atmosphere, we need a dense, low boiling point gas that can be easily extracted from somewhere. CO2?
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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