Fly me to the M(O2)n: Euro scientists extract oxygen from 'lunar dust' by cooking it with molten salt electrolysis Scientists at the European Space Agency are trying to extract oxygen from something very close to lunar soil. The ESA team can't try their technique on actual lunar soil samples: the amounts brought back are tiny and too valuable. Instead, the boffins have constructed a chemical equivalent, and are investigating, at a new …
Using kitchen salt is a bit of a no-no since the metal you end up with is sodium which would grab the oxygen molecules at the other end of the cell and burn. Which is why you use CaCl2 instead as metallic calcium is much safer and more tractable.
Also since the chloride is retained the CaCl2 could be reconstituted for further O2 production.
...and I have to admit to being very surprised that no one has actually tested it given how important the method would be for staying rather than just visiting the moon.
You would have imagined that the US at least would have done some testing, given their obvious liking for Robert Heinlein's SciFi
It's a bit like testing if things fall on the moon. It's theoretically a given, that rock with some oxygen (could even be trace) will be able to be heated/etc to extract said oxygen.
Figuring out a cheap, easy, useful and also method to get there and do it, is the hard part. Thus lots of paper theories, and less needed/desire to actually do it (the samples are rather rare, thus saved for more important/pressing tests).
"It's a bit like testing if things fall on the moon"
That particular experiment was performed at the end of the Apollo 15 mission.
Yes, unless they are planning on taking a nuclear power generator or a large number of solar panels, then it's not going to happen. Energy intensive processes require intense energy. The newer flexible and lighter solar power generating materials might be a good option. They could just be rolled out across the ground.
Ah yes, A 'The Moon is a Harsh Mistress' reference.
While its interesting... there is a lot more research that has to occur.
First is the salt a catalyst or does it get used up in the reaction and has to be replaced?
(Because the article talks about useful metals... I suspect that its used up so then the question is how much is necessary and how long it will last given that there's a cost of refining and transferring said salt to the moon.)
But how would you heat it? Could you get a solar / electric oven hot enough? What about a baby nuke generator?
Its interesting and of course... maybe one could fund a small robotic excursion to the moon to get a working sample?
Of course that would lead to better robotics and there are a couple of various science fiction stories around robotics... (cue the Issac Asimov references...)
Mine's the jacket with the mini-ipad loaded with a large collection of Sci-fi books. :-)
Since helium 3 is more common on the moon that anywhere on earth, one could use fusion to literally build oxygen out of helium building blocks. It is just a matter of swapping out protons and such until you get an O2 molecule. The moon would be much easier to do fusion on anyway because of the low gravity. Since they have had relatively good success doing so on earth these days, it should be even easier up there. Helium 3 fusion reactions have an advantage no other element has, because it puts off less radiation and more power during the fusion process. The disadvantage of high heat, would be offset by an easier process of magnetic containment. The equipment used would gain much less radioactivity during this process. It has a lot of advantages, all of which focus on the fact that the moon is as close to the perfect source and environment for such projects.
I can never remember which is which myself, so I went and checked, and found the explanation for your confusion. In a galvanic cell, e.g. a battery cell, the cathode is the positive electrode. But in an electrolytic cell, such as the article discusses, it's the negative one. So, you're both right, in different contexts.
Cathode is from the Greek kat + hodos, literally the way down. (Hence catastrophe, a "downward stroke"). It's the one, in the electrolysis cell, that the metals "come down" at. The anode is the "way up", the one that oxygen and chlorine are evolved at.
Incidentally two things occur to me about this research:
1.Molten salt electrolysis is not novel in the slightest, it's how you get aluminium, and how metallic sodium and potassium were originally made by Davy.
2.It is a very energy intensive process. In making aluminium oxygen is an unwanted byproduct that burns away the anodes. It tends to be operated where you have plenty of hydro power because you need to run the plant 24/7 - it really doesn't like cooling down. So, where is the power coming from? Not much available water on the Moon.
> nuclear batteries
What's a "nuclear battery"? If you mean radioisotope thermoelectric generators, like far-going space probes carry them, their output is pathetic (470 W for Pioneer's): You would have difficulties boiling water with them, much less salt.
As for solar, it has to improve a huge lot to be able to yield the thousands of MW needed. But whatever you do, there remains the small problem of the 2 weeks long nights (the moon being tidally locked, its day/night cycle is 28 days long).
Note that besides the energy needed to melt those rocks, you'll also need at least as much to collect them, transport them, crush them to powder, and remove the dross after the electrolysis has finished. The logistics of alumin(i)um production (from mining to ingot) are a pretty good indicator of the effort you would need.
On the other hand, given one person needs a little less than 1 l of O2 per day (IIRC), this could indeed work for smaller settlements, if only as a backup if local food plants don't yield enough.
It tends to be operated where you have plenty of hydro power because you need to run the plant 24/7 - it really doesn't like cooling down. So, where is the power coming from? Not much available water on the Moon.
Seems that using a molten salt reactor could be used both to refine the products and to generate power. It would still need some water, but it could still function pretty much as a closed system.
Having taken the HNC (Full time & didn't opt to upgrade to HND with a few extra units), the Level IV Analogue Principles & Maths unit was apparently the hardest one on the whole syllabus (& outside it), it was a right bastard & our lecturer into extreme calculus only made it worse.
We had "Dangermouse" twice a week & on Friday mornings for three god awful hours of him extrapolating things on his whiteboard (Made ITIL training look like a cakewalk) & expecting us to follow it (Friday mornings were best spent nursing hangovers & zoning him out (Much like "Chenoble" (doped up with lunchtime drinks) on Wednesday afternoons especially when goaded into his pet subject "Partial Address Decoding").
He only discovered this at the end of term test, when only 3 students (The Libyan refugee with a maths degree, a university drop out & a unemployed hippy\Unix bearded programmer who had taken the course rather than be put on some form of work detail in the community) managed to score over 47%.
He restructured his course & I just about managed to pass it (but that grade still cost me my conditional offer at Reading Uni to jump on the second year of a degree course though).
Level V Analogue Principles & Maths\Electronics, was taught at a much more practical level by the next tutor & I think I managed a reasonable merit or at least a better pass.
I did quite well with my OND but I was the last year to do the original (1970s?) version. That course worked better for me because it made you think rather than just throwing information at you and hoping it would stick. There was a time, thanks to that course, that I was quite good at calculus (though integration was always a pain). And I'd only left with school with a grade 2 in CSE maths.
First 'maths' lesson of the HND course we were given a page of calculus formula and told those would be the only ones we'd encounter in the exams. And maths was optional after the first term.
So it was back to listening to lecturers droning on and trying to make notes in an attempt to remember everything. Plus analogue electronics is just hard I remember one part where we were being taught how to create power supply circuitry. Every single step seemed to need yet another circuit to stabilise the last one.
Anyway I was already into computers and had begun to realise that I could program them as easily and 'thoughtlessly'(*) as I could talk to people. Possibly more so. So I decided to switch careers and get paid for doing something laughably easy. That was in the mid 1980s and I've never regretted that decision. Just call me the computer whisperer :)
(*)Without obvious conscious thought I should say. The results of my endeavours show that some form of mental processing is taking place but damned if I'm aware of it any more than I'm aware of how I construct coherent English sentences :)
The confusion is coming from the way the paragraph has been written :
Quote: " The oxygen in the regolith is released and travels through the molten salt mixture to be collected at the anode – the positively charged electrode – as gas. The various metals in the lunar soil are extracted too and pile up at the cathode – the positively charged anode."
If you can make sense of that, bully for you... I can't.
Well considering the Indians and Chinese recently managed to get robots to the moon to varying degrees of success, I'd say yes..
This however is all fun and games until they dig up something black... Very black. Beyond pentablack black... Say something 11 foot high, 5 foot wide and 1 ¼ foot deep (give or take some rounding off to make it 1:4:9).
I need a lie down now... nurse! My frog pills if you please?
IIRC in fully expendable mode, SpaceX could get a LOT to the moon, and not just in multiple launches (Falcon Heavy is huge, just not quite Saturn V size launches yet). Remember, they launched a car to the Martian orbital zone, and a little beyond.
However, the resources/need/want/logistics of the crew capsule are the thing many are waiting on.
It would be nice to know the energy needed per mol of oxygen and to see suggestions for where the energy would come from.
Solar. Lack of atmosphere and tidal locking would mean more watts per panel/reflector than are available on Earth, and no clouds to obscure them. Dust would likely be an issue though, especially as lunar dust is very abrasive due to the lack of weathering.
The thing that still intrigues me is whether we could vitrify lunar dust & rock, and then use a robo-brickworks to create construction materials for future lunar habitats. Which may also mean an ability to do some refining, ie collect anything outgassed & vacuum form molten rock into blocks.
Solar is not really that much better on the moon than on Earth. You have the benefit of longer days, but also longer "nights". So such long times without power is a worry, even if you get a small % boost from having no atmosphere.
The moon is tidally locked to the earth, not to the sun! XD
Depends on your value of "better".
Full sun on the moon is around twice the watts/sq area as full sun anywhere on earth.
There never any clouds on the moon.
Peak and average are perfectly predictable, and the long day means things that take time to
get going have that time. Being in vacuum makes insulation easier too.
So, at least in the lunar day, it's perhaps 4 times as good as the best earthly location for solar power.
I've lived on an off-grid solar power homestead since around 1980 and have been upgrading the entire time. It causes you to pay serious attention to such things. And it works even in Virginia, where we don't have 2 week days, but do have plenty of clouds, and are of course, beneath the entire Earth's atmosphere which eats around 50% of the solar flux even when it's clear.
i can even run computers so as to annoy other commentards on the Reg in January...
On earth PV peaks quite noriceably around noon when the sun passes through the least amount of breathable pollution. On the moon for 1/2 the time you can get max power from your PV - from sun up to sundown. No weather problems either. So I reckon you'd get 10 times the return you get on earth,.
Not to be sneezed at.
Well not while wearing a helmet.
You could do that with some kind of Moonbase, then possibly expanding outwards constructing & monitoring dumps of spent nuclear fuel, perhaps even taking off some of the heat in the silos at a later more advanced point for generating power.
I did see a series of documentaries on the feasibility on the whole concept back in the 70's, having it all up & operational by 1999.
It all looked very promising, but they then got bogged down into creating some form of H&S disaster simulation towards the end of the first one & created a worse case scenario of what would happen if the dumps blew up & went wildly off track after that, getting more ridiculous in the second set of 24 episodes of the series of 48 lectures.
Might I refer you to this Solar energy paper from 2018; https://www.e3s-conferences.org/articles/e3sconf/pdf/2018/24/e3sconf_solina2018_00053.pdf
This is notwithstanding the potential risk of meteor strikes, some mentioned the regolith as being extremely abrasive but considering the lack of atmospheric perturbation to deposit dust onto the panels which would have no moving parts that could disturb the dust causing ingress and wear. A 1 square metre Fresnel lens from an old telly is enough to melt good sized chunks of obsidian in seconds (3002 degrees Fahrenheit) https://www.youtube.com/watch?v=svAPyyUJUCo so I think solar would be the most obvious and easier to construct and ship to the moon.
..but considering the lack of atmospheric perturbation to deposit dust onto the panels which would have no moving parts that could disturb the dust causing ingress and wear.
Cheers for the paper, something for me to read tomorrow. As I understand things, there'd still be moving parts.. So challenges from dust being kicked up by lunar vehicles, people & machinery which would still be deposited given the Moon's gravity. And where microgravity might make life more complicated given dust could travel further, and no wind to blow it off mirrors, lenses and any joints that aren't carefully sealed. And I guess vacuum cleaners wouldn't work.
A 1 square metre Fresnel lens from an old telly is enough to melt good sized chunks of obsidian in seconds
Praise the Sun! But I think the biggest challenge is avoiding having to ship lots of mass out of our gravity well and into space, and thence the Moon and Mars. So being able to fab things like mirrors and lenses in situ would be handy. And gives me fun things to think about, like how to make flat, or the desired geometries in microgravity. I guess mirroring would be easier(ish) via vacuum deposition. And spheres would seem doable. Get your Space Balls here! Or genuine(ish) Lunar 'crystal' balls, packed full of energy and unsullied by human activities. Express delivery available from high orbit to avoid any pesky radiological concerns.
Mirrors are easy to produce in gravity - just spin the molten glass and you have a parabola! Also with lower moon gravity you dont have to use as much support to keep it 'in spec', You could probably build a 100m mirror on the moon and defend if from all comers until sunset!
Thanks. Sounds counter-intuitive though: Fresnel lenses are optical devices, and everything in a cathode-ray tube is electrical until the electron hits the phosphor on the inner side of the screen. So where is there a Fresnel lens? Between the phosphor and the viewer? *scratches head*
I'd hate to open (implosion!) one and find nothing...
Just who are these 'future settlers'? Have they been consulted. Have they volunteered to go an live on a hostile lump of rock some ~230,000 miles away from their home planet, or have they been 'volunteered' by someone else?
You wouldn't get me up there for all the tea in China! And that's a lot of tea!
I can't imagine who they might be. I for one will stay right where I am in the Olduvai Gorge, And what is this 'tea' you talk of - sounds a bit exotic? Eating grubs, roots and antelopes was quite good enough for great gran Lucy, and she lived right into her late teens so I don't see why we should change our habits now.
Sadly we don't know the actual perceived quality of life of our ancestors, but a lot of religions (including the Bible) look back to the time of hunter gatherers as being a "golden age" and regard the coming of agriculture and herding as a step backwards (what do you think Genesis 3 is really about?)
Dunno, but if it was anything like Roddenberrys prior documentary Genesis 2, would have been more about the navel of civilisation.
Icon - Doesn't care about network censorship & displays her belly button frequently to anyone interested. enough to film it
Sounds a really good.
Perhaps the next idea will be how to get a mains extension lead, or at least a football pitch or ten of solar panels, to supply enough juice to boil a million fresh goose eggs?
Perhaps a pump and length of hose draped back to the Earth's atmosphere would be cheaper? Make the hose out of diamond and you could turn it into a space elevator too ...
Make the hose out of diamond and you could turn it into a space elevator too ...
Not quite a space elevator, but a relevant XKCD nontheless:
"Make the hose out of diamond"
A bit brittle for your application I think. Probably spider web would be better. Since it's a demanding application, might need mutant spiders.
For some reason, I find the notion of mutant spiders bred for super strong web material acceptable as an engineering solution, but -- on another level -- a bit creepy.
"Maybe a better option would be to use partially spent nuclear fuel, the energy density is still good enough to make it a viable source of energy."
Nuclear power seems a reasonable solution for power on the moon. But, there's one thing. Nuclear power plants here on Earth are really heat engines that run off the thermal energy difference between a working fluid heated in the reactor and some cooling entity -- typically a lake, river, or ocean. On the moon, you'd need a probably need a large radiating array to provide the cool side. And half the time you'd need to shade the array from direct sunlight. That's all probably doable. But likely kind of complex.
Maybe solar power and a BIG battery would be simpler.
"Out of...erm...curiosity, how does Curiosity's nuclear power source work on Mars?"
Thermocouples. Thermocouples are heat engines also I think. At least they need a temperature difference to function. Curiosity apparently cools the cold surface by conduction/convection(?) to Mars very thin but quite cold atmosphere. http://large.stanford.edu/courses/2012/ph240/belanger2/
> how does Curiosity's nuclear power source work on Mars?
It uses a Radioisotope thermoelectric generator, like most space probes. RTGs are the go-to energy source for everything that can't use solar panels because it's either too far from the sun (outer solar system), bound to be in the shade a lot of the time, or when solar panels are impractical or insufficient.
"Maybe solar power and a BIG battery would be simpler."
A big battery for general purposes maybe, but not necessary for turning cucumbers into sunlight...I mean salt into oxygen - just produce enough during the daylight hours to see you through the dark times.
Valuable to whom exactly, and why? The only value I can see in any lunar dust that's been bought back is the value to the scientific community to actually conduct research experiments such as the one proposed in the article. If the only "value" is an economic one derived solely from "well... it cost us a lot to go there and get it back... so you can't have it", then overall I can't actually see the point in bringing it back in the first place.
That there are things called "plants" that will convert Carbon Dioxide and water -- both byproducts of human metabolism -- to Oxygen and a bit of waste material. Not only that, but the waste material is said to be edible (as long as it isn't something called "kale").
Further research is needed.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
