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Science

UC Reactor Makes Martian Fuel 32

Engineers at the University of Cincinnati are developing new ways to convert greenhouse gases to fuel to address climate change and get astronauts home from Mars. UC: UC College of Engineering and Applied Science assistant professor Jingjie Wu and his students used a carbon catalyst in a reactor to convert carbon dioxide into methane. Known as the "Sabatier reaction" from the late French chemist Paul Sabatier, it's a process the International Space Station uses to scrub the carbon dioxide from air the astronauts breathe and generate rocket fuel to keep the station in high orbit. But Wu is thinking much bigger.

The Martian atmosphere is composed almost entirely of carbon dioxide. Astronauts could save half the fuel they need for a return trip home by making what they need on the red planet once they arrive, Wu said. "It's like a gas station on Mars. You could easily pump carbon dioxide through this reactor and produce methane for a rocket," Wu said. UC's study was published in the journal Nature Communications with collaborators from Rice University, Shanghai University and East China University of Science and Technology. Wu began his career in chemical engineering by studying fuel cells for electric vehicles but began looking at carbon dioxide conversion in his chemical engineering lab about 10 years ago.

"I realized that greenhouse gases were going to be a big issue in society," Wu said. "A lot of countries realized that carbon dioxide is a big issue for the sustainable development of our society. That's why I think we need to achieve carbon neutrality." The Biden Administration has set a goal of achieving a 50% reduction in greenhouse gas pollutants by 2030 and an economy that relies on renewable energy by 2050. "That means we'll have to recycle carbon dioxide," Wu said. Wu and his students, including lead author and UC doctoral candidate Tianyu Zhang, are experimenting with different catalysts such as graphene quantum dots -- layers of carbon just nanometers big -- that can increase the yield of methane.
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UC Reactor Makes Martian Fuel

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  • Carbon dioxide is CO2. Methane is CH4.

    Do they hope to also find water or where is the Hydrogen coming from?

    • All I can think of is that they are creating an oxidizer (liquid oxygen), and supplying the carbon to make the methane from the process— you would still need to ship the hydrogen there. The good news is that is most of the mass needed. The bad news is you need to store the hydrogen in a way that it can be safe and leak very little.

      • ... you need to store the hydrogen in a way that it can be safe and leak very little.

        Just extract the hydrogen from any unused hydrazine fuel, like in The Martian, and ... oh, wait. :-)

    • I think the idea is that there is in fact quite a lot of water on the martian ice caps and in craters.

      https://en.wikipedia.org/wiki/... [wikipedia.org]

      "More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters (115 ft).[13] Even more ice is likely to be locked away in the deep subsurface.

      • Not sure that makes sense. The Sabatier reaction *priduces* water (and methane), starting from CO2 and H2. To first create hydrogen from water and then run the Sabatier reaction would be hugely energy intensive. Although it does leave you with some extra O2, which would be useful...
        • You're producing rocket propellant from its combustion products. Of course its going to be energy intensive, that's what the multi-megawatt solar farm is for.

    • That's what I was thinking. Of course, while there is water on Mars, I don't think the details on how to collect it have been worked out. There seems to be a few steps missing in how the process is going to work.

    • by ceoyoyo ( 59147 )

      If you mean on Mars, you bring the hydrogen with you. It's light. This is SpaceX's plan, and a big reason why their raptor engines burn methane.

      If you mean on Earth, well, we've got a fair amount of the stuff lying around.

      • No, SpaceX's plan is to mine water ice and get the hydrogen from that. Hydrogen is bulky and difficult to store for long periods, they'd be sacrificing hundreds of tons of useful equipment and supplies to carry it instead.

    • Carbon dioxide is CO2. Methane is CH4.

      Do they hope to also find water or where is the Hydrogen coming from?

      I think the more important use is on Earth, where hydrogen can be produced with excess peak solar or wind derived electricity, a cathode, an anode and water - IIRC.

      If it scales to an industrial means to convert coal power stations exhaust into methane for fuel or ethylene for plastics it means less CO2 in the atmosphere. The heat and the density of the CO2 in the exhaust from a coal station would provide additional energy to the drive the Sabatier reaction [wikipedia.org] within the conversion process, increasing eff

    • by MrKaos ( 858439 )

      Carbon dioxide is CO2. Methane is CH4.

      Do they hope to also find water or where is the Hydrogen coming from?

      Perhaps that's just part of the big issue about going to mars. Perhaps once we get there we start pushing ice at Mars to evaporate the water into the atmosphere.

  • 96% CO2 concentration in the atmosphere. Utterly barren. Cold as dry ice. It'd be easier to live in Antarctica, actually. Or at the bottom of a shallow sea.

    OK, the whole "multi-planetary species" thing that Musk is always talking about sounds exciting and adventurous. But in the end, Martians will have to fight for literally every second of their existence, just to stay alive. Mars is the God of War, not a Mother.

    • You notice those promotional films by SpaceX always end with the landing on Mars. What comes after is left to your imagination.

      If Musk can get a rocket to Mars, he certainly deserves his props. But as difficult as landing on Mars is, that may turn out to be the easiest part of the mission.

      I suppose they can establish a small research base there, similar to the ISS. But at the moment, turning Mars into attractive real estate is way beyond our technology. I don't think we'll be seeing retirement villages on M

    • Well, getting away from fools sounds like a compelling reason. You might encounter fools on Antartica.

  • by phalse phace ( 454635 ) on Friday September 24, 2021 @04:06PM (#61829649)

    Can we call this martian fuel "Illudium Pu-36?"

  • What is the difference between a martian fart and a sandstorm?

    The sandstorm doesn't glow in the dark.

  • The Sabatier reaction takes carbon-dioxide and hydrogen (conspicuously absent from TFA), and produces methane and water.
    With energy, you can split the water into hydrogen and oxygen, and feed the hydrogen back into the first step.
    Since CO2 is an in situ resource on Mars, that means 1 gram of hydrogen could make 7 grams of methane and 16 grams of oxygen, that's a 1:23 reduction, not 1:2
    In other words, it does more than "save half the fuel", you only need to carry about 1/20th as much.

    It's great that they're

    • by ceoyoyo ( 59147 )

      "you only need to carry about 1/20th as much."

      You need fuel to get there. The summary is suggesting that you need only half the fuel because you're going to make the half for the return on Mars.

      As you point out, you have to bring hydrogen with you, so you do have to bring a little bit of stuff for the return trip.

      What both you and the summary are missing is that annoying logarithm in the rocket equation. If you can make fuel at your destination, even if you have to bring a bit of stuff with you to do it, yo

  • A guy named Mark Watney can give us more details about the process, the needed power and it's practical uses, but he has a great lag when accessing /. - Expecting his replies in about 24 min.

  • Turning CO2 into methane requires energy, and thermodynamics tells us that this energy will be greater than what we will get from burning the same methane into CO2. Let's assume solar energy makes this a viable fuel production scheme.

    And if the goal is to address earth atmosphere greenhouse gases, methane is a more greenhouse potent gas than CO2, hence this will not reduce greenhouse effect. It can be a zero-sum game if all produced methane is burned, otherwise it makes the situation worse.

    • by ceoyoyo ( 59147 )

      It's too bad there's nowhere to store methane long term.

    • It is not realistic to think that all fuel burning applications will be replaced by renewables or by electricity. Aviation is the most obvious one. Electric aviation, especially long haul, is going to remain an elusive goal. So it makes sense to investigate methods of synthesizing fuel from atmospheric CO2. In some cases, CH4 may only be the first step. Liquid fuels may be synthesized from CH4. These can be stored really easily. And of course CH4 can be stored, too. There is already infrastructure in place

  • Seems criminal to not mention Robert Zubrin. I don't think he invented the idea of making methane on Mars using the Sabatier process, but he certainly helped promote the idea in his popular 1996 book "The Case for Mars."

  • Astronauts could save half the fuel they need for a return trip home by making what they need on the red planet once they arrive, Wu said.

    Yeah. Every kg of fuel you bring with for your return trip takes many kgs to get to Mars. And then each of those extra kgs you want to launch with takes many more again.

    Plus what does "half the fuel they need for a return trip home" even mean? If getting them home now needs 1000kg of fuel for the return trip then this reactor means they only need to bring a
  • Regarding making rocket fuel on Mars, the methane part is super easy .. we've known how to do that for well over a hundred years. The hardest part is extracting water from soil ice to make hydrogen. Given there are no frozen lakes on Mars, come on man how the heck are we supposed to mine ice/water on Mars? We can't even dig a trench autonomously on Earth, how the hell are we supposed to build a fully autonomous Martian mining operation within a decade? The ice is trapped in the soil, mining it and melting o

    • There was one plan put forward by Zubrin where an autonomous ship lands on mars and starts making fuel. I THINK (it has been a long time since I read it) the ship would bring hydrogen with it. I agree with everything you say. But when I read Zubrin's book, my impression was that he had given everything quite a bit of thought. Anyway, this is just a press release from a University of Cincinatti issued because two UC professors published something in Nature Communications. I wouldn't get to worked up over it.

  • by hackertourist ( 2202674 ) on Saturday September 25, 2021 @02:44AM (#61830731)

    On the ISS, the Sabatier process is used to combine CO2 (scrubbed from the air) with hydrogen (available from the Oxygen Generation System) to produce water. Any methane is vented to space. The ISS does not have thrusters that can burn methane. Increasing ISS altitude is usually done by the thrusters on visiting vehicles, not by thrusters on the ISS itself.

  • Just plug your Magic Methane Maker into any available wall socket on mars, and POOF! you get methane. What could be easier?

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