NASA has MOXIE, but rivals reckon they can do better for oxygen on Mars
- Reference: 1660807691
- News link: https://www.theregister.co.uk/2022/08/18/mars_oxygen_moxie/
- Source link:
Writing in the Journal of Applied Physics , an international team of boffins led by University of Lisbon physicist Vasco Guerra say they've managed to test a design that can do the same thing NASA's Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) does – but [1]without the need for intense heat and pressure.
Not only does their design improve on MOXIE's ability to harvest breathable oxygen, it can also be used to create fuels, carbon-based fertilizers, and animal feed. It can also synthesize a variety of organic molecules, the researchers said.
Move over MOXIE?
MOXIE produced oxygen on Mars in a [2]toaster-sized unit , but it required very specific conditions to do so: it had to heat the Martian air to 800°C (1,472°F) and re-pressurize it to one Earth atmosphere, making it far denser than the pressure on the Red Planet.
Guerra's team, on the other hand, proposes using non-thermal plasma and specialized conducting membranes. Combined, the design forms a plasma reactor that can operate directly in Martian conditions without the need for heat or re-pressurization. According to the paper, Mars's atmospheric pressure is actually "ideal for plasma ignition."
[3]NASA wants a hundredfold upgrade for space computers
[4]NASA to send prototype robot surgeon into space
[5]ESA kicks ExoMars rover down the road, to 2026 at best
[6]NASA: Mars rocks won't make it back to Earth until 2033
In the paper, the researchers detail the two separate oxygen-generating experiments they carried out: the first using DC glow discharge plasma super chilled to Martian temperatures, and a second that used microwave discharges operating in a simulated Martian atmosphere.
The paper describes the results as "very encouraging considering that the plasma setup used was designed for fundamental research and is far from suited to the development of a prototype." The DC experiment reportedly reached CO 2 dissociation (the separation of carbon and oxygen) rates as high as 30 percent, while the MW experiment reached a 35 percent conversion rate.
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Based on their preliminary results, the team sketched out what an optimized system could produce and arrived at 14 grams of oxygen an hour in a plasma reactor weighing 6 kilograms – 2.3 grams of oxygen per kilogram of equipment.
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For comparison, NASA's MOXIE unit weighs [10]17.7 kilograms and can top out at 10 grams of oxygen an hour, the space agency said.
Not so fast
The fact that MOXIE has actually made oxygen on Mars weighs heavily in its favor, as do some major drawbacks that the experimenters concede, as MOXIE leader and MIT experimental scientist Michael Hecht [11]reiterated to Science .
The membrane used in Guerra's experiment, known as a mixed ionic-electronic conduction (MIEC) membrane, is developmentally at its "very first steps" in being coupled with plasma, the paper notes. Additionally, the researchers list "stability in CO 2 and the possibility of back reactions" that can lessen the membrane's effectiveness as challenges to MIEC use. That, we presume, are challenges to overcome to make a practical device.
Hecht told Science that energy requirements and oxygen storage needs could make Guerra's device bulkier than MOXIE, defeating much of its benefit. "There's nothing wrong with the plasma technique other than it's a lot less mature," Hecht said, adding that a cash infusion from a space agency could make the tech mature enough to take to Mars. ®
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[1] https://aip.scitation.org/doi/full/10.1063/5.0098011
[2] https://www.theregister.com/2021/04/23/mars_moxie_oxygen/
[3] https://www.theregister.com/2022/08/17/nasa_space_computer/
[4] https://www.theregister.com/2022/08/03/iss_robot_surgeon/
[5] https://www.theregister.com/2022/07/20/esa_exomars_delay/
[6] https://www.theregister.com/2022/07/28/nasa_mars_rock/
[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Yv4N2c39oenbQ5QKIjsp9wAAAAA&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Yv4N2c39oenbQ5QKIjsp9wAAAAA&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Yv4N2c39oenbQ5QKIjsp9wAAAAA&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[10] https://mars.nasa.gov/mars2020/spacecraft/instruments/moxie/
[11] https://www.science.org/content/article/plasma-reactors-could-create-oxygen-mars
[12] https://whitepapers.theregister.com/
Re: all the O2 requirement of one adult
So, we'll basically need to send one machine per crew member ?
Either that, or someone will have to [1]stop breathing .
[1] https://www.youtube.com/watch?v=UNYBtjHAuSA
By converting different molecules directly from the Martian atmosphere
That's very impressive. It's been known for a long time that water ice on the icy bodies in the outer solar system separates out into its hydrogen and oxygen components when exposed to local radiation and that the atomic oxygen recombines into O2, the hydrogen goes off into space. So breaking up CO2 with plasma is reasonable.
As the device consumes CO2, could it be used also on Earth? In that experiment, what does the carbon become?
Interesting question! I would guess maybe yes, but not as efficient, since the article states Martian atmosphere is ideal for the plasma thingamajig they're using.
In any case it's very low volume, so I guess the power and volume requirements to use such technology to remove CO2 from Earth's atmosphere would be completely disproportional to the utility. Much better to plant a few million trees (or just stop using the land - I've seen examples in Brazil where just leaving the land undisturbed for 5-10 years it will start to re-forest by itself)
Hazard
" The resulting equipment could be used to produce the necessary materials for human colonization, too "
As (if I remember right) Larry Niven stated in the '60s:
"The more you control your environment the more hazardous it becomes to live in it".
The thought of relying absolutely and permanently on any machine for my source of oxygen terrifies me, particularly if rescue is so far away. Divers (and even astronauts) do for only limited periods - not for their entire natural lives.
Good job....
... not a bad volume either...
An adult breathes about 11,000 litres of air/day, about 2,200 litres of O2, which at 1.43 g/l at stp is about 3.1 kg/day or about 130g/hr.
So the quoted 10g/r and 14g/hr for what is essentially experimental equipment is pretty good. Scaling up 10X production normally could be done without requiring 10X increase in equipment mass as well, so achieving a 30kg or less machine that can provide all the O2 requirement of one adult should be quite possible.