Extra Oxygen?

JoshNH4H · 2013-12-03 00:16:57

A colony on Mars will grow food to feed itself. Growing this food will inevitably result in the production of Oxygen. In fact, it will be just the right amount of oxygen that the loop will be closed: When people eat the food, its organic chemicals will be metabolized, using the oxygen that the crops they're from produced, and turned back into Carbon Dioxide. I would expect that the system would be slightly oxygen poor because some small amount would escape from the habitat.

However, there will be a much more significant source of Oxygen: Metal and Polymer production. Starting from Metal and Carbon oxides, this will produce materials that have less oxygen than they started with. They oxygen has to go somewhere, and my question is: What should we do with it? Is there some use it could be put to or would it simply have to be released into the atmosphere?

RobertDyck · 2013-12-03 01:04:55

Biosphere 2 found they did not have enough oxygen. They carefully studied and calculated before building the habitat. However, there was one factor they did not realize before the experiment: decomposition of organic matter in the soil. They built it in a desert, so had to truck in soil. To reduce expense, they thought they could bury some twigs to enrich the soil. But the microorganisms that decompose those twigs consumed oxygen. This resulted in such a deficit, they had to add air from outside.

So my assertion is plant growth will provide most of the oxygen, but there will always be unknowns that unbalance the system. The smaller the system, the more precarious the ecosystem. And the first Mars settlement will be much smaller than Biosphere 2.

That said, metal and polymer production should produce more than the deficit for life support. So yes, you will have surplus.

JoshNH4H · 2013-12-03 01:34:57

It's unfortunate that Mars is by and large not a reducing environment, so that the extra oxygen can't be used to produce energy.

Terraformer · 2013-12-03 03:54:39

You say that as a bad thing, but when terraforming begins...

At least it allows you to keep reserves on hand, in case your crop fails...

Tom Kalbfus · 2013-12-03 07:49:44

JoshNH4H wrote:

A colony on Mars will grow food to feed itself. Growing this food will inevitably result in the production of Oxygen. In fact, it will be just the right amount of oxygen that the loop will be closed: When people eat the food, its organic chemicals will be metabolized, using the oxygen that the crops they're from produced, and turned back into Carbon Dioxide. I would expect that the system would be slightly oxygen poor because some small amount would escape from the habitat.
However, there will be a much more significant source of Oxygen: Metal and Polymer production. Starting from Metal and Carbon oxides, this will produce materials that have less oxygen than they started with. They oxygen has to go somewhere, and my question is: What should we do with it? Is there some use it could be put to or would it simply have to be released into the atmosphere?

Oxygen can be used as an oxidizer for fuel to run vehicles such as methane powered Mars rovers. When you combust methane, you produce carbon dioxide and water, the carbon dioxide can simply be released into the atmosphere and there is no need to carry that around, but the water is somewhat scarce so it needs to be kept, and if can be used for drinking, growing food or it can be recycled back into methane using energy inputs and carbon dioxide from the atmosphere. the excess oxygen can also be released into the atmosphere if no other use can be found for it, if nothing else, it will recombine with the rocks and soil elsewhere, or it will stay in the atmosphere for a while and perhaps help with terraforming.

Terraformer · 2013-12-03 07:58:22

You're still going to end up with excess oxygen, because you produce all the oxygen you need for combusting methane when you synthesise the methane...

JoshNH4H · 2013-12-03 12:10:30

RobertDyck-

I don't disagree that there may be significant oxygen losses, as Biosphere 2 demonstrated. However, I would add that their oxygen loss came from concrete curing in Biosphere 2. Concrete probably won't be the material of choice on Mars because of the low temperatures and the difficulty of finding raw materials. In any case, I would expect that there would be some oxygen losses in the hab but these are going to be small relative to the oxygen produced by smelting Iron and producing organics.

Here's an idea: How much ozone would be needed to significantly reduce the surface radiation? Mars' atmosphere at the present time is .13% Oxygen, for a partial pressure of .78 Pa. This corresponds to about 3e13 kg of Oxygen in the Martian atmosphere. If we're producing 1000 tonnes of Iron per year, we'll produce about 3e5 kg per year of Oxygen, which is unfortunately pretty negligible in comparison. The Earth produces about 1.6 billion tonnes of Iron per year, 230 kg per person. Because Mars will be heavily industrialized and rapidly expanding, let's say we use ten times that-- 2.3 tonnes per person per year. If you have 10,000 people on Mars, that's about 6e6 kg of Oxygen per year.

Maybe if we could find a way to get it into the upper atmosphere we could develop some kind of ozone layer?

RobertDyck · 2013-12-03 13:47:23

UV light from the Sun will interact with O2 to form ozone. Yes, ozone absorbs UV much better, and ozone can decompose into O2. It forms an equilibrium. Once you have an oxygen atmosphere, ozone will spontaneously form. On that previous Mars Society forum, I argued that sufficient ozone will form to make surface UV the same as Earth. Ozone is dependant on the quantity of molecular oxygen (O2) and intensity of UV. Light intensity that reaches Mars is less than Earth, including visible and UV, but my assertion is this process will form an equilibrium resulting in the same surface UV as Earth. Once the partial pressure of O2 is the same.

But that will take a long time. Creating an oxygen environment on a planet will take a lot. Haven't even tried to work out how long. Did calculate time to produce greenhouse gasses, based on work by Dr. Chris McKay et al and Martyn J. Fogg. But once greehouse gasses have formed, the planet will take time to warm. That will sublimate dry ice to form a thick CO2 atmosphere, and melt water ice to form liquid water. A great start, you could then seed plants and lichen and peat. Black spruce trees can grow directly in a peat bog. Once you have a boreal forest, it's just time until you have a breathable atmosphere. No idea how long.

Time for greenhouse gasses: take an ore processor as big as one in the Tar Sands in Alberta. Construct 10 industrial sites, each with 4 such ore processors. Mine ore to produce raw materials, and chemical factories to produce greenhouse gasses. Use thorium nuclear reactors for power, fuelled by Mars thorium. Once they're all in full operation, 13 years for all greenhouse gasses. That's a lot of work, but one person's lifetime.

Tom Kalbfus · 2013-12-03 16:39:39

The Martian Ozone layer would be almost 3 times as thick as on Earth, and at the distance Mars is from the Sun, its going to be awfully hard to get a suntan on Mars once its terraformed. I think you'll see a lot of pale skinned people walking around on this Mars.

JoshNH4H · 2013-12-03 17:38:52

RobertDyck, I was wondering if something could be done to make the oxygen preferentially float to the upper layers of the atmosphere, for example releasing it all at once at a higher temperature so that it would float up.

Ultimately, I fully expect that the extra oxygen will be useless. But one can hope.

Perhaps it can be used in airlocks, sacrificially, allowing a single door ( ) much simpler airlock design.

RobertDyck · 2013-12-03 18:26:53

I would like more oxygen close to the surface. So plants can grow, and eventually people can breathe without an oxygen mask.

JoshNH4H · 2013-12-03 18:59:37

Long term, absolutely, but short term the excess oxygen is on such a small scale that I'm probably being silly to even suggest that it could be useful for any kind of global environmental modification

Void · 2013-12-04 09:24:24

As water seems to have been found even in "Dry" soils, I would suggest for the early term, making tanks or reserviors (Covered), filled with water, would allow extra oxygen to be stored in a disolved state in the water, available for emergency extraction if necessary.

Here is an article on extracting disolved oxygen:
http://en.wikipedia.org/wiki/Artificial_gills_(human)

Also such reservoirs would most likely be cold, but it might be possible to include some animal life that consumes Oxygen and Methane Seeps. This would allow such a disolved air tank to earn it's keep when it was not serving as an emergency Oxygen supply.

I choose Methane, as the food for the animals, because if Methane were to be manufactured for fuel and as feedstock for industrial purposes, it would always be desirable to be able to manufacture more than can be stored. In that case if excess Methane is also available it can be injected into a water tank/reservoir as discribed above to help activate a chemically driven biology.

Here is a not very related article I will connect to here. I found it while searching for the artificial gills. It is kind in the line of thinking anyway:
http://downloadsquad.switched.com/2007/ … ed-oxygen/

Last edited by Void (2013-12-04 09:26:32)

SpaceNut · 2013-12-04 17:45:03

We have known for sometime that the solar wind blows away the outer most atmosphere of mars. http://science.nasa.gov/science-news/sc … st31jan_1/

It flows away in all directions traveling 400 to 800 km/s with Mars's magnetic umbrellas act like miniature magnetospheres. They ward off the solar wind in their vicinity and harbor pockets of gas ionized by solar UV radiation that would otherwise be blown away.

That said thou even Earth losses some of it for the same reason with a greater magnetic field than that of mars so what does the field strength have to do with the loss rate....

http://www.space.com/11187-earth-magnet … -wind.html

The effect of the solar wind on Earth is less uniform than on Mars and Venus, but apparently the net loss rate is about the same.
Other ions besides oxygen have been measured escaping into space, such as ionized carbon monoxide and carbon dioxide molecules, which also include oxygen. Hydrogen ions are also being lost, but they are difficult to distinguish from solar wind protons.
Even so, researchers assume that approximately two hydrogen atoms escape for each oxygen. 3.5 billion years. Imagining this water spread evenly over the surface, Mars, Earth and Venus would have each lost a layer of water 30, 9 and 8 centimeters thick, respectively.

http://www.nasa.gov/content/goddard/mav … ic-levels/
MAVEN Solar Wind Electron Analyzer Seeks Answers at Microscopic Levels

SpaceNut · 2014-12-21 20:38:29

Australian university students aim to generate first 'breathable' air on Mars Josh Richards, a physicist from Perth, plans to send a system that produces oxygen from water to the Martian surface, as part of the Mars One project that aims to establish a human colony on Mars. Richards said. "Then we'll use the electricity from the solar panels to split the water into oxygen and hydrogen and we'll essentially prove that you can produce oxygen on Mars that future settlers will be able to use."

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#1 2013-12-03 00:16:57

Extra Oxygen?

#2 2013-12-03 01:04:55

Re: Extra Oxygen?

#3 2013-12-03 01:34:57

Re: Extra Oxygen?

#4 2013-12-03 03:54:39

Re: Extra Oxygen?

#5 2013-12-03 07:49:44

Re: Extra Oxygen?

#6 2013-12-03 07:58:22

Re: Extra Oxygen?

#7 2013-12-03 12:10:30

Re: Extra Oxygen?

#8 2013-12-03 13:47:23

Re: Extra Oxygen?

#9 2013-12-03 16:39:39

Re: Extra Oxygen?

#10 2013-12-03 17:38:52

Re: Extra Oxygen?

#11 2013-12-03 18:26:53

Re: Extra Oxygen?

#12 2013-12-03 18:59:37

Re: Extra Oxygen?

#13 2013-12-04 09:24:24

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#14 2013-12-04 17:45:03

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#15 2014-12-21 20:38:29

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