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Mars Space Science

Plasma Reactors Could Create Oxygen On Mars (science.org) 54

sciencehabit shares a report from Science Magazine: Last year, NASA achieved something science fiction writers have been dreaming about for decades: It created oxygen on Mars. A microwave-size device [called MOXIE, or the Mars Oxygen In-Situ Resource Utilization Experiment] attached to the agency's Perseverance rover converted carbon dioxide into 10 minutes of breathable oxygen. Now, physicists say they've come up with a way to use electron beams in a plasma reactor to create far more oxygen, potentially in a smaller package. The technique might someday not just help astronauts breathe on the Red Planet, but could also serve as a way to create fuel and fertilizer, says Michael Hecht, an experimental scientist at the Massachusetts Institute of Technology. But Hecht, who leads the oxygenmaking rover instrument, says the new approach still has a number of challenges to overcome before it can hitch a ride to our solar neighbor.
[...]
In the lab, he and his colleagues pumped air designed to match the pressure and composition of Mars into metal tubes. Unlike MOXIE, they didn't need to compress or heat the air. Yet, by firing an electron beam into the reaction chamber, they were able to convert about 30% of the air into oxygen. They estimate that the device could create about 14 grams of oxygen per hour: enough to support 28 minutes of breathing, the team reports today in the Journal of Applied Physics. Guerra's team still needs to solve some practical problems, Hecht notes. To work on Mars, the plasma device would need a portable power source and a place to store the oxygen it makes, all of which could make it just as -- if not more -- bulky than MOXIE, he says. If space agencies were willing to spend millions of dollars developing it -- as NASA did with MOXIE -- the plasma approach could mature, Hecht says. He especially likes how the electron beam could be tuned to split other atmospheric molecules, such as nitrogen, to create fertilizer. "There's nothing wrong with the plasma technique other than it's a lot less mature [than MOXIE]," he says.

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Plasma Reactors Could Create Oxygen On Mars

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  • Is this a system that conceivably can be used to generate oxygen on the go in an astronaut's backpack, meaning at least that part of breathing is unlimited?
    • Is this a system that conceivably can be used to generate oxygen on the go in an astronaut's backpack, meaning at least that part of breathing is unlimited?

      Let's hope it's not something the size of which that we saw in the movie Total Recall

    • by ceoyoyo ( 59147 )

      You'd need to feed it power. You'd almost certainly be better off with an extra tank. If you really need to go for a long time, add a scrubber.

      • The extra bottle depends on how long you want to travel for. Thereâ(TM)s definitely a crossover between this and bottles of oxygen. Scrubbers donâ(TM)t give you any extra oxygen, they just remove the CO2.

        • by ceoyoyo ( 59147 )

          Oxygen isn't usually the limiting factor. 78% of the air you breathe in nitrogen, 21% oxygen, and if there's 1% CO2 in it you'll die. The air you breathe out is 70% nitrogen and 16% oxygen. A rebreather recycles the nitrogen and that exhaled oxygen, scrubbing out the CO2. If it's efficient, you can go for a long time with just a small bottle of oxygen.

          An oxygen generator makes sense at a base, not so much in a vehicle, and not at all carried on your back.

          • by jbengt ( 874751 )

            78% of the air you breathe in nitrogen, 21% oxygen, and if there's 1% CO2 in it you'll die.

            More like 4% to 5% CO2, but your point still holds.

            • by ceoyoyo ( 59147 )

              Sorry, that was supposed to have been 10%, 100,000 ppm. Estimates suggest 4-5% would probably kill you if you breathed it for an hour or so. 3% would probably do the job just fine on Mars because even if you didn't actually lose consciousness your cognitive functioning would decrease to where you might open the door to let some fresh air in.

        • by tragedy ( 27079 )

          The extra bottle depends on how long you want to travel for. Thereâ(TM)s definitely a crossover between this and bottles of oxygen. Scrubbers donâ(TM)t give you any extra oxygen, they just remove the CO2.

          I've always wondered about the use of oxygen bottles vs oxygen candles. Going by scuba tanks, the filled tank is only about 18% oxygen by weight. Space equipment made with stronger, more lightweight, more expensive materials might hold more, of course. Still oxygen candles can release up to 60% of their weight as oxygen. Does anyone know why oxygen candles are not preferentially used vs. oxygen tanks? Is it because you can beat their storage/weight with better materials and spherical tanks? Fire/explosion c

          • by jwdb ( 526327 )

            Interesting, I hadn't heard of these before... But, as a diver I know I wouldn't want to have an extreme exothermic reaction strapped to my back.

            Average scuba tanks are 21% O2 by volume, matching the atmosphere, but may be other ratios depending on the task at hand. You can use a 100% O2 tank safely down to 6 m, at which point the risk of seizure from oxygen toxicity becomes too high for most. If you want to use an oxygen candle at greater depth, you'll also need an inert gas source to dilute the O2, and pr

            • by Alcari ( 1017246 )

              Average scuba tanks are 21% O2 by volume, matching the atmosphere, but may be other ratios depending on the task at hand. You can use a 100% O2 tank safely down to 6 m, at which point the risk of seizure from oxygen toxicity becomes too high for most.

              Not exactly. the gas inside the tank is 21% (or whatever you want, really), but don't forget the tank itself it also very heavy and quite bulky, especially when adding all the other equipment.

              • by jwdb ( 526327 )

                Sure, agreed. I'm ignoring the weight and volume of the tank itself since an oxygen candle would also need a fair bit of infrastructure, quite possibly of comparable weight.

                If that "18% by weight" number was supposed to account for the weight of the tanks as well, then it's very far off: the tanks I use typically weigh between 20 and 30 lbs and carry 5 lbs gas even when full, so ballpark they're 15-25% gas, or 3-5% oxygen when using standard air.

            • by tragedy ( 27079 )

              I can certainly see not wanting to have an unquenchable exothermic reaction strapped to your back. I should also note that contaminants like oil can turn oxygen candles into bombs. A few years back some sailors on a nuclear submarine, for whatever reason, lit an oxygen candle that had been contaminated with oil and were killed in the resulting explosion. So there are definite potential risks, but pressurized cannisters can explode too. I suppose pumping gas into a pressurized container is a lot simpler, in

              • by jwdb ( 526327 )

                What you describe doesn't surprise me - one thing that any diver learns when they start experimenting with enriched gas (i.e. O2 > 21%) is that you have to be very careful to keep your tanks clean. Pumping pure oxygen into a tank who's intake has been contaminated by oil (say, from an unclean compressor) is a good way to blow up a fill station. The results are generally not pretty.

                Once compressed, the tanks are much less of an explosion risk even if they contain pure oxygen. They could burst at the seams

    • Or would the heat produced offset any benefit from splitting our own atmospheric CO2?
    • written by Lester Del Rey in 1952 had his Mars explorer protagonists swap their backpack air tanks with a portable compressor.
      Even the indigenous Martians had been using a compressor crudely made from copper. Part of the book's plot revolves around this device.
    • by jonadab ( 583620 )
      > Is this a system that conceivably can be used to generate
      > oxygen on the go in an astronaut's backpack

      It doesn't matter if the oxygen generator is small enough to carry; you're not going to carry it, because it's not going to be smaller than a tank of oxygen that will outlast your pressure suit's carbon dioxide scrubber cartridge.
      • it's not going to be smaller than a tank of oxygen that will outlast your pressure suit's carbon dioxide scrubber cartridge.

        Hmmm, well, since my dive buddy needed to (re-)fill the oxygen tank in his re-breather system after most dives, but only change the CO2 scrubber after a weekend's diving ... that might only be true "in spirit".

        But yes, his system's software did include a counter for "litres breathed since CO2 scrubber changed", and he would get alarms on his HUD if he went over-hours. He had to pay at

  • by cstacy ( 534252 ) on Wednesday August 17, 2022 @06:06AM (#62796249)

    Get your (ionized) gas to Mars!

  • It was further noted that the presence of Ar and N2 from the Martian atmosphere contributes to further enhancing plasma dissociation and that the required power for discharge operation is typically 100W and can be as low as 20W at gas flows in the range 2–10sccm,48,49 perfectly attainable on Mars.

  • by Antique Geekmeister ( 740220 ) on Wednesday August 17, 2022 @06:40AM (#62796297)

    Mars is even more suitable than Earth for solar sail harvesting of icy ring chunks from Jupiter, dropped into convenient low areas like the Hellas impact basin, where the water and any generated gases would be partially collected by being 4 kilometers before normal Martian altitude. With enough orbital bombardment, quite large lakes could be formed there for use in iindustry and to generate oxygen for life support systems. It's the sort of terraforming described for Martian colonists in the Man-Kzin War anthology.

    • Each one of these small steps to permit us Earth creatures to simulate Earth conditions on Mars is, to my mind, incremental in a process that moves in the right direction, but fundamental differences of a very large order probably require centuries to create a satisfactory transition to be accomplished, although sequestered bubbles of possible habitation probably can be achieved initially. Much of Earth vegetation is vastly interconnected with subsoil fungus complexes with yet to be understood functions and
      • Centuries is probably optimistic unless we're willing to dedicate truly enormous resources to a project that won't see dramatic results within the career lifetime of the politicians who would have to approve the spending. I'm not optimistic.

        On the other hand, a whole lot of Earth microbes are already able to survive Mars-like conditions, some even consuming the toxic perchlorates as their preferred energy source. And microbes are effectively immune to high-energy radiation - it may well kill the microbe i

    • You'd also heat your atmosphere significantly with each impact - particularly as you get the atmospheric pressure up above it's current near-vacuum. That's going to put a cap on your bombardment rate - you'll have to allow time for the atmosphere to cool off between landings.

      It's the sort of terraforming described for Martian colonists in the Man-Kzin War anthology.

      In a different universe, the originator of that SF franchise terraformed a satellite of a gas giant ("Building Harlequin's Moon", https://en.wik [wikipedia.org]

  • The article is really thin on explanations as to what exactly they mean by "more"

    I mean, the easy way to make more oxygen than MOXIE, is to add a second MOXIE unit. BAM! Double the oxygen production.

    Their talk of power supply seems to hint that it needs more power than MOXIE, so probably not more oxygen per watt.

    Their mention of bulk suggests that a complete system would be bulkier than MOXIE, so not more oxygen per liter of equipment.

    It could be more oxygen per kg of equipment - but then you'd think they'd

    • I imagine that they donâ(TM)t know yet which would be smaller until they research how small they can make them.

      • Sure. And when they know how small/energy efficient/etc. they can make them I'll be happy to let a claim of "making more oxygen" sit unchallenged.

        As it is, it sounds rather like a claim that my vehicle is more compact than yours because my motor is smaller than your car - if it were really more compact I would be making less obtuse claims.

  • by xession ( 4241115 ) on Wednesday August 17, 2022 @09:04AM (#62796611)
    You just have to get into the underground oxygen generator caves. I saw it in a documentary a long time ago.
  • Don't bother. The solar winds will eventually blow away any atmosphere you put on Mars.
    We can visit Mars. There is no point in living there.

    • This has nothing to do with terraforming. The amount of oxygen produced by a device ten times larger would be just enough to keep a handful of people alive in a sealed environment. I'm sure they would do their best not to leak any of it into the atmosphere.

      • I set the subject to be about terraforming. Then I tied my post to original article with my second to last sentence. So this thread is about terraforming and you're off-topic.

  • The real question is if it's more efficient or more effective than the current means for removing carbon from CO2. If it's more efficient then it's also applicable on Earth. If it's more effective then it will allow CO2 to be quickly converted in batches when we have excess energy. If it's neither then it really only helps on Mars.

    • by jbengt ( 874751 )

      The real question is if it's more efficient or more effective than the current means for removing carbon from CO2.

      Apparently it makes O2 and CO, so, it would need an extra step of removing CO in order to remove the carbon.

  • Nobody is actually going to survive on Mars anytime soon or surviving the trip there. I do hope Musk goes though, because we could urgently do with less rich assholes on this planet.

  • "That's the atmosphere processor, remarkable piece of machinery, completely automated.
    Oh, we manufacture those by the way".
    Weyland-Yutani.
    Building Better Worlds (tm)

  • Wake me, shake me, when the air on Mars is breathable. Not til then.

  • With the rampant deforestation (still) going on, maybe we could use some of those converters here on Earth.

  • That's an atmospheric processing unit. We manufacture those, by the way.

  • If this device can turn about 30% of the CO2 in a sample into O2 (and CO, but you can catalytically convert that back into CO2 for the next pass), then it could turn the 0.06 bars of Mars's current (mostly CO2) atmosphere into 0.04 bars of CO2, and 0.02 bars of O2.

    Which is still close enough to a vacuum that you'd die choking on the foaming remains of your boiling lungs about 15 seconds after you started breathing it. (It'll take most of those seconds for the catastrophic loss of blood pressure to start ki

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