What can I say except that in the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

Look, the codes are printed in dark red on light red in the manual. There's no way anyone could photocopy that.

So not only is it ridiculously unethical, it's utterly pointless and a sad waste and inconvenience or worse for everyone involved? So, a typical DRM scheme.

From what I could find, it would work out to about 47 or 40 with a reasonable safety margin (and because it's a nice round number, though now I realize I should have gone with 42 because it's what you get when you multiply six by nine and also how many roads a man must walk down). Of course, that would only be if you were sourcing all of their oxygen through this system without any recycling (like with plants, or some catalytic electrolysis process to break down CO2). If it's supplemental, to replace losses, the number it could support should increase to thousands.

Not if the oxygen partial pressure is the same. However, if the atmosphere is just oxygen at about 3 psi, they will have to deal with dehydration (as is common on jet flights, but worse) and pressure related issues that are not conducive to long-term good health.

Helium would have most of the same problems as pure oxygen. In a nitrogen/oxygen atmosphere the nitrogen is a heat sink and the density of the air slows down convection. In a helium/oxygen atmosphere, even at full pressure, the helium is barely a heat sink at all, and the air density is barely above just the oxygen alone, so convection is barely slowed. Ultimately, nitrogen is the best choice, and throw in all the argon you can get your hands on.

It is survivable from the perspective of getting enough oxygen. In fact, breathing would be even easier because the air would be less dense. However, there are a series of other problems that would make it suboptimal. Dehydration is a major one. Then there are various pressure related issues including lung problems. Long term, it's not very good for human health, and it's not comfortable. There's also the increased flammability. While the partial pressure of the oxygen is the same, the nitrogen in the atmosphere normally acts as a heat sink, and the lower density of the air overall increases the supply of oxygen to fires because of faster convection. The same things are true if you make up the difference in pressure with low density helium.

Pure O2 atmospheres seem like they solve a lot of problems, but they introduce their own. Generally speaking, even just for the comfort factor, it makes sense to have a full density atmosphere in a long-term space habitat.

As another poster pointed out, they're not talking about helium-3, just regular old, second most common element in the universe, helium. By mass it's available in the regolith at about the same abundance as nitrogen by baking it. Of course, by volume at 1 atm of pressure, it's available in much more abundance than nitrogen from the regolith. The fact that it will leak out like crazy and cause communications issues. As observed, you would be squeakier, but also it's harder for sound to transfer to the eardrum in a heavily helium atmosphere, not to mention that there's much greater attenuation of sound. People wouldn't be able to hear each other across much shorter distances than in a regular atmosphere, even if they could adjust to the weird sound of voices.

It's available from regolith, though at a high extraction cost. I've written a number of posts on this subject elsewhere in this thread, but if you need nitrogen on the moon, there's plenty available at the poles in the form of ammonia. It's right there with all the ice.

If you need a MegaWatt just to run the process though, you have a sort of reverse catch-22 if you want to use this to expand a small base quickly. You pretty much have to start with large base power infrastructure just to run the process. Although, you probably don't need a continuous 1 MW, just for long enough to run 1 batch, but it's not clear how long that would be, and capacitors have a weight cost as well. Basically, any bootstrapping done with this process sounds like it's going to need a fairly large starter base to bootstrap from.

From what I can find, it would actually be more along the lines of 1.6 kg per hour. In terms of life support, that would supply a number of astronauts in the mid forties. That is, of course, only if this process is somehow the only method you have for supplying oxygen to the astronauts rather than re-using what is in the habitat through, for example plants, or a CO2 cracking process. So, this really should only be needed for replacing lost oxygen, or for expansion of the habitat volume beyond what was shipped from Earth.

If we compare to the ISS, which loses about 4% of its atmosphere per year, a moon base should fare better. The ISS is a hideous agglomeration of modular units with a very high surface area to volume ratio, sealed together with synthetic rubber, some of it quite old at this point. So, I would expect a moon habitat to be able to manage much better than the ISS and be down below 1% loss per year.

In terms of building a base and expanding it, filling up the volume gradually with in situ collected atmosphere, this might be a viable strategy. However, one of the problems you run into is nitrogen. We need nitrogen or some other inert (to us) gas to keep the pressure high enough for comfort and to avoid some health issues. I explored this in another post. We can get that from regolith by baking it (and some would be a byproduct from the process in TFA), but we would need a lot more energy expenditure and effort to get the other gases than the oxygen. We could ship it there as ammonia and also get some hydrogen out of the deal to make water. However, in that case, we're talking about a lot of mass to move relative to close to a quarter that mass in oxygen. All in all, since both water ice - which can be electrolyzed to get oxygen - and ammonia are available at the poles, it might ultimately be simpler just to mine a small amount at the poles rather than massive amounts around the base. Basically, if you're going to process that much regolith, you need excavation equipment, trucks, etc. When you actually add up all of the mechanical activity to do all that local mining, it probably adds up to many trips to the poles and back, even accounting for the excavation work you would probably need to do in order to build a road there.

The details I could find suggest about 39 kilograms of oxygen per day, or about enough for 47 astronauts (though you would want a safety margin, so probably no more than 40).

That raises the important question of what degree you need sustained electrical power for. If you need it for industrial processes, sure. For life support? Not so much. Or, at least, not so much compared to the average electric power requirement. To keep astronauts alive, you need electric power for things like atmospheric conditioning, heat, etc. That can take potentially tens of kiloWatts per astronaut. However, a lot of that is for things that can be made in batches that will last the two weeks of lunar night. Oxygen, for example. You also need to do CO2 scrubbing. In a long term moon base, you will want to do that in a way that preserves oxygen, rather than just permanently storing the CO2 or venting it. That means either plants or an energy intensive process to unbind the oxygen and the carbon. However, you can certainly just use C02 sorbents to store the CO2 without wasting any power until you have abundant power in the day cycle at which point you can bake out the CO2 and process it some other way.

There are things like heat, which you can handle by just using a big container full of regolith and heating it up during the day cycle and taking the heat from it through heat exchangers during the night. That can handle hot water as well. For water purification, you just purify all of it during the day cycle and you use fresh water from storage tanks and store wastewater in storage tanks during the night.

Same goes for just about every process. Sure, you still need some power for things like lighting and various electronics, but that can be pretty minimal. Essentially the formula that power storage requirements equals full solar cycle requirements divided by two is complete nonsense. A generous couple of kiloWatts per astronaut overnight gives us about 15*24*2=720 kWh per astronaut. Obviously the most advanced technology goes to moonbase regardless of cost, so we can assume .35 kWh per kg with existing technology and with even higher prospects on the horizon such as .5 kWh per kg. Going with the .35, that gives us about 2.06 tons of batteries per astronaut. Not small, but we're talking about something that can last for decades.

Of course, that's just if they are using batteries for storage. This is a little roundabout, but something to consider for a moon base or any sort of space station is water purification. The purification systems on the ISS use a number of processes for highly efficient water re-use, but one of them is distillation for the most fouled wastewater (toilet water, and not the perfume kind). Now, instead of distillation, you can electrolyze the water instead. This takes about 6 times the energy, but bear with me, you get the energy back. Once electrolyzed, you store the hydrogen and oxygen. When night rolls around, you can then run the hydrogen and oxygen in a fuel cell to get both electricity, heat, and fresh water. All things that you need anyway. That 720 kWh of electricity you need per astronaut can be had by electrolyzing and then recombining in a fuel cell (or some sort of thermal power generation system) about 360 liters of water. A human produces about 1.4 liters of urine per day and the average human flushes the toilet about 5 times per day with a very efficient low-flow toilet using 3 liters per flush. Over fifteen days, that would work out to close to 500 liters of toilet water per astronaut per day/night cycle. Sure, you could use suction toilets that use no water and make it just the 50 or so liters of urine. Of course, basically every astronaut ever considers the vacuum toilets in space to be one of the worst parts of the experience. So why use them when you could use more comfortable flush toilets (although they might need a redesign considering how water might act in the lower gravity) and have the system be combined with a power storage system that should be considerably lighter than batteries? You get electric power storage, very clean recycled water, comfortable toilets, and any efficiency loss just turns into heat, which you probably need to heat your base anyway. The downside is that there are going to be more maintenance requirements for such a system than for batteries. Of course, it's not clear that they will be much higher than they would be for a traditional water purification system anyway.

You're right. It's a pity that oxygen needs to be used immediately and can't be stored.

If you're talking about for the power source, we have to put the "about one MegaWatt" into context that is missing from the summary and article. That 1 MW may represent a lower bound for the energy they need, but the missing context is how much oxygen that will actually produce. To figure that out, we need a few other bits of information. First is how much oxygen a person needs. For a single human, NASA puts that at an average of .84 kg per day. Second is how much oxygen the process actually produces. For this, we have to understand that the headline isn't really true. This is not really a new process. It's already known to use about 1 kg of oxygen per about 25 kWh.

So, we just need to put those in the same terms. Watts are Joules per second, so we have to put all of these into per second rates. .84 kg per day per person is .233 grams per second. 1 kg of oxygen per 25 kWh at 1 MW is 11.111 grams per second. So, the MW of electricity going into this process would produce enough oxygen for 11.111/.233=47.6 people. Accounting for some wastage, etc. we can round that down to about 40 people. In other words, about 25 kW per person. So, more than an average home, certainly, but the electricity is definitely cheaper than transporting oxygen to the moon via rocket.

Basically, power to generate oxygen would become the number one power sink for life support. We could say about 30 kW total per astronaut (there would be other power requirements for potential industrial processes, this is just to keep the astronauts alive). Your solution is nuclear batteries, though you don't really define what that actually means. You could mean reactors, or you could mean RTGs, or maybe something different? With space grade solar panels on the moon, we're talking about something like 400 Watts per square meter. Half the time it's night time and then there's the angle of the sun relative to the panels (it's probably cheaper to just ship more panels than ship solar tracking mounts) so probably you'll get an average of something like 150 Watts per square meter. So, that means about 200 square meters of panels per astronaut. That's not too bad really. Obviously you don't have to run the oxygen generators all the time, only when there's significant power available. You could also potentially set this sort of thing up at the poles in regions of endless light and truck the generated oxygen to wherever your station is, though it doesn't seem like that would be necessary.

Of course, all of this is assuming that, for some reason, every breath of oxygen that your astronauts take has to be produced from regolith. This simply isn't the case for a few reasons. First is that, if you have a long-term base, then you will want closed loop food production. This means growing plants. With high yield crops, it turns out you need something like at least 50 square meters of crops to feed an astronaut. The thing is, you only need about a third that many square meters of crops to recycle enough oxygen from CO2 for a single astronaut. So, bottom line is that if you're feeding your astronauts in situ, you're recycling all of your CO2 into O2 in situ. Which means that producing oxygen from regolith to breathe is only needed on a supplemental basis. Of course, that doesn't mean you don't do it anyway, but you do it to make water, not breathing oxygen. For that, you can use hydrogen brought from Earth, or you can get hydrogen in situ. There's about 75 ppm in regolith, and you can get it out just by baking it at about 700 Celcius. You need about 15 metric tons of regolith for 1 kg of water, which will make 9 kg (9 liters) of water when you combine it with oxygen. It would take about 2600 kWh to produce that hydrogen. Comparing that to the 200 kWh it would take to produce the oxygen for the 9 liters of water, that's a big difference. Technically, the oxygen producing process would produce some hydrogen too, but it would be small compared to the amount of oxygen. It is worth noting that you get 33.3 kWh or heat back when you burn the hydrogen to make water, but that only gives you back a little over 1% of the energy you put in. You can do much more with regenerative heating systems that take the heat from already processed regolith and transfer it to the next batch. That should get your power requirements down by about 50% to more in the range of 1300 kWh to produce a liter of water. To put that in energy terms that compare to Earthly usage, that's like driving a gasoline powered car 500 miles to the supermarket and 500 miles back to get 2 one gallon jugs of water. There is some question of whether you could basically create a Bussard collector to simply harvest solar wind, but it's not clear the yield would be higher. It is considered a possibility that the electrostatically levitated particles that float above the surface of the regolith might function as a natural collector, making it possible to collect much higher concentrations of hydrogen by sweeping them up over a wide area, so that might be another way to get hold of hydrogen with less power.

Of course, a lot of this assumes that you aren't being very selective and that you're just digging up regolith around some random spot you set up your base with no prospecting. In reality, you would most likely go after spots with mineral deposits with considerably more hydrogen and/or oxygen, which do exist on the moon. Those could change the energy requirements quite a bit. Of course, if you're doing that, you could just go all the way and just mine truckloads of actual ice right from the poles. If you're doing that, not only do you get water, but all that mucking around with drawing out oxygen from regolith goes by the wayside and you use a lot less power to just electrolyze the water.

What a lot of this ignores is that a gas that might be more of a problem to get locally is nitrogen. It makes up most of our atmosphere. It's basically inert as far as humans are concerned, but, without it we have a pure oxygen atmosphere. That's not actually much of a fire hazard as long as we keep the air pressure down to oxygen partial pressure levels. Trouble is, that's around .21 atmospheres. While there's no oxygen deprivation, there are various effects like dehydration and pressure related issues that can be damaging to humans in the long term. Also, while it's not the same as a pure oxygen environment at one atmosphere, nitrogen in the atmosphere does help suppress fire, mostly by acting as a heat sink. You can replace some of it with helium, argon (our atmosphere is already about 1% argon), and neon. Of course, you'll want the mix to be right, or your voice will sound funny (not to mention there can be some biological effects from, for example, argon in too high a concentration). Helium makes your voice squeaky, while argon makes it deeper while neon only makes a very tiny change. In the right mix, the density is the same as nitox and it's neutral.

Although gaseous nitrogen is basically inert to humans, nitrogen is actually essential to human life. Plants, humans and every other known form of life rely on fixed nitrogen, even though only certain micro-organisms actually directly fix it from the atmosphere. Proteins, DNA/RNA/, ATP/ADP, vital hormones and vitamins, chlorophyll, etc. all rely on bound nitrogen. Those exist in a bound nitrogen cycle that's semi-seperate from the unbound nitrogen in the atmosphere except for certain micro-organisms that bind or unbind it. There are other things that can unbind it like fire, electrical discharge, etc. but generally you have unbound nitrogen and bound nitrogen with some types of bacteria as intermediaries. So, in your habitat, you would presumably keep your biologically important nitrogen in a cycle where it persists in the actual living things like astronauts, plants, cultivated microorganisms/fungi and any experimental/agricultural animals, etc. or in biological wastes/composts/etc. Some of that would need to be replenished with losses but, for the most part, every astronaut would presumably arrive with their inherent supply and enough additional supplies to keep the cycle going. The same should be true for the station atmosphere. However, you would need to be able to make up losses from in situ resources.

  Now, if you're baking the rocks for hydrogen, you get about the same amount of nitrogen from the process. You also get some argon, helium, and neon. The thing is, in terms of volume at one atmosphere, it's mostly helium, even though the relative mass isn't that huge. Since helium also escapes more easily through seals, that does give you more opportunity to continuously replace it, but obviously some of that is just going to be excess that you can't use in the internal atmosphere because there's only so much sounding like Donald Duck people can take. The argon and neon are going to be in relatively small amounts compared to nitrogen in terms of what you get out of a given volume of regolith. The end result is that, for the internal atmosphere, it's still going to be mostly nitrogen with all of the argon and neon you can get combined with it, and just a tiny amount of helium to top off and maybe balance out the argon. The rest of the helium either gets discarded or saved in tanks for possible industrial uses. There are some other gases that might be produced. Trace amounts of krypton and xenon. Some radon that will not be wanted in the atmosphere. Various compounds that are basically all undesirable.

Of course, just like with the oxygen and hydrogen, if you want to skip all the messing around with regolith, you can just mine the poles and those truckloads of ice will also have ammonia. That can fulfill both your bound nitrogen requirements since you can use it directly for fertilizer (or process it into urea) and you can also break it down for atmospheric nitrogen. You won't get much in the way of the other gases we discussed coming from the regolith, but it's not like you actually need those in the atmosphere, they were mostly just filler to make up the pressure.

So, in summary, these are interesting techniques mentioned in the article, but regolith extraction seems to have a scale problem. Either your operation is so small scale that MegaWatt regolith reactors and the kind of mining operation you would need to feed them are probably too much for your astronauts, or your operation is big enough that mining trips to the poles have such high yields that a massive mining operation around your base seems a little silly compared to one expedition to the poles to get dozens of times the yield. Sure, there might be a middle ground in between, however, if you're in that middle ground, you're almost certainly looking at future expansion, so you have to consider if the sunk costs of putting in the effort for local mining are worth it when it will be obsolete in a few years when your moon base is bigger. Of course, if you really want to think long term, you have to consider that the polar ices are not a renewable resource. Of course, looking ahead that far, interplanetary shipping of resources from, for example, the asteroid belt, has to be a consideration.