Oct 20 2017

Making Oxygen on Mars

Mars baseAt some point humans will travel to Mars. It seems inevitable, the only question being when that will happen. Optimists like Musk think it will happen before mid-century, but that may not be realistic. There are significant logistical hurdles without clear solutions.

Some argue, and I agree with this strategy, that we should focus first on a moon base. The moon is a lot closer, which solves many problems right there. But otherwise it would have many of the same challenges as Mars, and so if we develop a base on the moon we can use what we learn to be better able to tackle Mars. Further the moon can be a literal launching pad for Mars.

While Mars has some extra challenges, it may have some advantages as well over the moon. NASA experts have observed that Mars has just enough of an atmosphere to be a problem. It has 1% of the pressure of Earth, which means for astronauts it is functionally the same as a hard vacuum. You still need pressure suits, pressurized living spaces, and you need a supply of air to breath.

Further, it is not thick enough to help braking when landing on Mars, but it is thick enough to cause friction. You are better off having a thicker atmosphere you can use, or no atmosphere to get in the way. From NASA’s perspective, it is just a nuisance.

Although wispy, it is enough to cause dust storms, even planet-wide storms that last for weeks. This dust is more annoying to NASA than sand was to Anakin Skywalker:

“If you’ve seen pictures of Curiosity after driving, it’s just filthy,” Smith said. “The dust coats everything and it’s gritty; it gets into mechanical things that move, like gears.”

It is not strong enough, however, to blow people and equipment around as imagined in the book and movie, The Martian. That was one major scientific inaccuracy in an otherwise very diligently accurate book. The author acknowledged this and admitted it was a convenient plot device.

So the atmosphere of Mars seems to be a major negative, but can it be of any use to future Martian colonists? Perhaps – as a source of raw material

The Martian atmosphere is 95% carbon dioxide. Therefore there is a lot more CO2 in Mars’s atmosphere than Earth’s. Earth has 0.04% CO2. So even though the atmosphere is 100 times thicker, that is still only about 4% of the CO2 in the atmosphere on Mars.

If fact if we ever wanted to terraform Mars and give it a breathable atmosphere, we would have to get rid of all that extra CO2.

Well, it’s possible to kill two (or maybe even three) birds with one stone. A new study looks at the plausibility of using plasma to split CO2 into oxygen and carbon monoxide. Here is the highly technical summary:

Herein, it is argued that Mars has nearly ideal conditions for CO2 decomposition by non-equilibrium plasmas. It is shown that the pressure and temperature ranges in the $\sim 96 \% $ CO2 Martian atmosphere favour the vibrational excitation and subsequent up-pumping of the asymmetric stretching mode, which is believed to be a key factor for an efficient plasma dissociation, at the expense of the excitation of the other modes. Therefore, gas discharges operating at atmospheric pressure on Mars are extremely strong candidates to produce O2 efficiently from the locally available resources.

What all this means is that if we had an energy source on Mars we could use that to drive a process by which plasma is used to make oxygen and carbon monoxide from the CO2 in the atmosphere. The primary use of this process would be to make oxygen for colonists – oxygen that can be stored in tanks and used in space suits or habitats.

That could be a massive advantage to any missions to Mars, especially one that endeavors to establish a permanent colony on Mars. One of the biggest challenges to such a colony would be resources. A colony would need, at a minimum, energy, food, oxygen, and water. I could add shielding to the list, to protect against cosmic rays.

Energy can be made locally with solar panels. That is how our Mars rovers operate. However, solar panels are less productive on Mars because the sun is farther away. Also, the dust storms are a major problem for solar panels. Burning fossil fuel is not practical – that is just one more resource you will have to bring with you. Nuclear batteries are a great option, as long as they are handled safely.

I do wonder what power source a Mars colony would use. Probably solar panels and nuclear batteries, but I wonder if that will be enough. Perhaps they will use small self-contained nuclear reactors.

In any case, once they have an energy source, where will they get their food, water, and air. Research is underway to see how hospitable Martian soil is to agriculture. A self-sustaining colony will have to, at some point, grow their own food.

There is plenty of water on Mars, but that will have to be extracted. You can split water into oxygen and hydrogen, but that uses up your water.

Splitting CO2 to make Oxygen seems like a perfect solution. The raw material is readily available. It seems that extracting oxygen locally would be absolutely necessary to any self-sustaining colony.

If, in the far future, we want to terraform Mars this would also be a useful process. It will add a little O2 to the atmosphere (not nearly enough, but it’s a start) and can get the CO2 down to breathable levels.

The carbon monoxide can also be used as a raw material to make fuel, essentially serving as an energy storage medium.

This is one tiny step that may help our plans to visit and colonize Mars, but it is interesting to think about what the challenges are and what possible solutions may be.

15 responses so far

15 thoughts on “Making Oxygen on Mars”

  1. petrossa says:

    what will never cease to amaze me that here on earth we have absurd stringent regulations as to the amount of penetrating radiation a human being is allowed to sustain daily (less than the background radiation in many places) but we happily discuss sending those same human beings not only at least six months into a radiation hailstorm but also imagine ‘normal’ life is in anyway possible on planets/moons without a magnetic field/atmosphere to reduce exposure.

    It’s either one or the other. Or the levels of radiation exposure are severely overstated on earth or understated elsewhere.

    Makes me think of the 1980’s when houses where build according to heat isolation standards thereby trapping (amongst others) radon gas emissions making them unsafe for habitation according to radiation standards

    What i want to say with this diatribe is that either we accept way lower overall health regulations for all planets/moons including earth or we accept that for humanity living elsewhere than on earth is a pipedream.


    Still wondering how to keep co2 levels as low as the paris convenant in a subsurface colony (the only way to keep radiation at ‘safe’ levels) which expands faster than co2 scrubbers can be installed/fabricated. Hasn’t the EPA declared co2 to be a pollutant?


    on the subject of emissions, the need for methane scrubbers comes to mind. That methane can most efficiently be oxidized but brings to mind the problem of c02 scrubbers and how to produce to extra oxygen.


    Further thought brings me to oxygen production. The only efficient way of producing oxygen on a oxygen poor planet/moon is electrolysis of h2o. Not only depleting the reserves of h2o but as a side effect (besides needing lots of energy) producing highly explosive and hard to store hydrogen gas which can only be utilized efficiently by oxidization

    Imho there are quite a few realistic hurdles to be taken before science fiction becomes reality

  2. bend says:

    Building a base on the moon first? Something on which you agree with the president! I have no opinion on whether humans should build a base on the moon before going to mars, but I did find this article interesting.
    I particularly like the line about if your goal is driving from LA to NYC, you don’t stop to build a home in Houston. Maybe an unfair comparison, but clever.
    What I do have an opinion on is manned space exploration in general. It represents a huge opportunity cost. The money spent to build a habitation for humans on the moon and to send humans to mars would be much better invested in unmanned space travel. Let’s send more robots farther and farther rather than sending a handful of people to the most remote camping site in history. We’ll learn more about more that way.

  3. mink says:

    It’s fun to think about colonizing planets. You bring up the idea of terraforming… I can imagine all kinds of cool things: diverting comets rich in water (and therefore oxygen) to crash to the surface, extracting oxygen from minerals (probably too much energy required), pulling it from the CO2 already there, etc. No matter what means are used to create an O2 rich atmosphere, I wonder if there’s enough gravity to actually hold an atmosphere dense enough for us to breathe?

  4. Pete A says:


    Good points.

    When the bacteria and viruses they carry with them to Mars mutate (due to both radiation and genetic drift), let’s hope they have have an expert and the necessary equipment to combat the ensuing diseases.

    Or, to save the weight of all that equipment, they could just take with them: homeopathic remedies, herbs, reusable acupuncture needles, a Reiki master’s set of three tuition courses[1], and Gwyneth Paltrow.

    [1] Each of the travellers will have to provided with enough money to pay for the courses.

  5. Maculus says:

    I think that reducing the CO2 levels by creating carbon monoxide might not be the ideal terraforming outcome. I would imagine that some kind of photosynthesis would be a more likely candidate, but first we need a big magnetic field generator at the L1 Langrange point.

  6. Maculus says:


  7. “Mars imposes restrictions on freedom that are worse than under the most terrible totalitarian regimes on earth”. — Charles S. Cockell

    Elon Musk will not be the first human to set foot on Mars, he knows better than to fly to that hellhole. Mars is a place of nearly insuperable difficulties and only the most hardy among us are going to enjoy exploration there. And this talk of a self-sustaining Mars colony, is that serious? Is it now settled that humans can reproduce and raise healthy children in .376 g ? I see potential for a Martian population composed of scientists, workers, extreme sport enthusiasts, all temporary residents, each completing a tour of duty/employment/adventure and then returning to Earth — possibly never to return to Mars.

    Venus seems a better choice for a self-sustaining human colony one day, as hellish as it is now. Frasier Cain says terraforming Venus would be insanely more difficult than terraforming Mars, “but it’s still possible”. The proposal of Geoffrey A Landis of NASA (linked below) makes a case for Venus such that I could in good conscience wish for children to grow up there, floating above the Venusian surface, whimsically,


  8. Michael Finfer, MD says:

    The one thing that I see as a deal breaker here does not seem to be addressed by anyone in any way.

    Perchlorates have been detected on Mars by both the Phoenix lander and the Curiosity rover, suggesting that they may be widespread in the Martian soil. These substances are highly toxic when inhaled. How are we going to protect the crews from that? When they get there, will they be able to go outside? If they do, will we be bringing back corpses?

    I’d like to see someone with some biomedical and engineering knowledge tell me how that will be addressed.

  9. Bend – That is a terrible analogy, Here is a better one. Imagine if we colonized a new continent, like North America, but there were no natives. We have colonies on the East Coast Our goal is to establish new colonies on the West Coast. Do you think it would be useful to establish settlements between the two coasts first, or skip over the whole continent and go right to the other coast?

    Michael – Perchlorates are a problem, but not for breathing – well, not until we try to terraform Mars and breath its atmosphere, but that is so far in the future it is not an issue for now. Having a base on Mars – the issue is can we use the soil to grow stuff. It may need to be treated to remove the perchlorates. Research is under way looking into growing food in Martian soil.

    But yes – there are lots of technical hurdles to colonizing Mars.

  10. Pete A says:

    “But yes – there are lots of technical hurdles to colonizing Mars.”

    Understatement of the year, methinks.

  11. Felix Gutt says:

    As a huge fan of Heinlein’s The Moon is a Harsh Mistress and Arthur C. Clark’s Venus Prime series I might be a little biased but for my preferences there’s a value in doing hard things because they are hard (to paraphrase Kennedy).

    Getting to the moon and back would be so much cheaper than getting to Mars and back it does seem to make sense to create a colony on our moon first. With a less expensive trip we’d be able to experiment more in situ rather than in labs or simulations. We’d be able to continue developing our technology for descending into Mar’s atmosphere in parallel. One successful sky crane landing is just one success. I’d like to see whatever technology ends up being used proven a bit more reliable before I take the ride. Maybe a couple of robotic sample return missions to prove the technology would be a good first step.

    On the other hand if the goal is getting to Maars, going to the moon first might end up being a wash or worse in resources. The opportunity cost of trying to make and support a base on the moon might outweigh any benefit it might bring from being a cheaper place to refuel ships or as a test bed. Perhaps just making one big initial push to Mars might be better. I’d also be nervous that we’d end up deciding the moon wasn’t where we’d want to be and abandon it with significant life span left in it a la the ISS. Or we’d spend so much money building a moon base we’d give up on going to Mars.

    Regardless, so long as we’re spending money on science, research and space I am happy. Mars first, the moon first… it’s all good to me.

  12. Cary says:

    “Further the moon can be a literal launching pad for Mars” I do not understand why people keep making this claim. The math simply does not show that. To get to the surface of the moon from LEO it takes about 6km/sec of delta-v. With proper aero-capture and aero-braking you can get to Mars for about 4.5km/s. Citation:http://www.marssociety.org/home/about/faq/#Q12 It’s a bit scary to me to think that major policy decisions could be made on the grounds of such a flawed assumption. There are great reasons to go to the Moon, such as exploring it’s most newly discovered lava tubes for instance, but refueling to go to Mars just isn’t one of them. Personally I think lunar tourism would be an excellent way to fund Mars mission. A hotel on the moon that people could go to for a few weeks/months and come back home would be awesome!

  13. Charon says:

    Can we stop asking “how” for a second and answer “why”?

    Seriously, why?

    I want a telescope on the Moon, and crazy as that is, I can’t even imagine why the hell we’d want to put humans on Mars. WTF.

  14. Charon says:

    And before anyone says “to have humans survive catastrophe on Earth”, I’ll remind you you’re assuming you can survive in a radiation-bombarded vaccuum and terraform a planet more hostile than any place on Earth has been since the Hadean, with wacky gravity our bodies didn’t evolve for. I don’t care what global warming / supervolcano / asteroid impact you think is going to befall the Earth, but afterwards it will still be more survivable than Mars.

    I say this as a professional astronomer, who loves the idea of exploring space… in useful ways. Which don’t involve absurdly weak and needy meat bags actually traveling there.

  15. chikoppi says:

    [Charon] I want a telescope on the Moon, and crazy as that is, I can’t even imagine why the hell we’d want to put humans on Mars. WTF.

    If you were a geologist or biologist, do you think you’d have a different perspective? Why bother to put humans on the moon? What good ever came of that?

    The simplest reason to visit Mars is to try and answer the questions that we have and discover new questions that we haven’t yet thought to ask.

Leave a Reply