Why use water to create oxygen?

[Bob_Herzog]

Ok they said it they based the game on science and ideas. In the streams for the game so far the only option to get oygen was to get a constant stream of water and people actually used it and nothing gets recycled at all. The ISS is currently working on a cycle to have a continious cycle running from water to oxygen and hydrogen then hydrogen and carbondioxite to water again and then start from the begining. It is a closed system with very little loss (the CO2 can be taken from what the colonists exhale and if need be from mars atmopshere). And that ignores plenty of theories and even current testruns around to reclaim oxygen directly from CO2 (which is what most of Mars's atmopshere is made of).

Same is true for water used by the humans and eventual for gorwing plants. In a closed system a good water reclmation system and a initial amount of the resource is most of what you need.

So given it is set in the future will we get the option to use a cyclesystem like that in order to massivley reduce the need to mine for those resources?

Don't get me wrong fining water is still quite important since it would be way to costly to ship the amount you need. But a space colony working in habitats should be big on recycle systems.

 

[keynes2.0]

Water recycling can't be perfect. Maybe the constant need just represents the portion that is lost? Getting that loss down to a minimum might not be a priority because the oxygen will be a byproduct of both hydrogen and carbon production For every molecule of methane you produce to launch your rockets with, you will produce two molecules of O2 as well, one from the hydrogen and the other from the carbon.

 

[Orlunu]

Water recycling can't be perfect. Maybe the constant need just represents the portion that is lost? Getting that loss down to a minimum might not be a priority because the oxygen will be a byproduct of both hydrogen and carbon production For every molecule of methane you produce to launch your rockets with, you will produce two molecules of O2 as well, one from the hydrogen and the other from the carbon.

Partly the amounts seem very off, and it'd be nice to see more active reference in terms of techs and buildings to such an important aspect. Also, it seems to be thecase that these "by-product" sources you mention aren't modelled, which is a crying shame.

 

[Bob_Herzog]

Water recycling can't be perfect. Maybe the constant need just represents the portion that is lost? Getting that loss down to a minimum might not be a priority because the oxygen will be a byproduct of both hydrogen and carbon production For every molecule of methane you produce to launch your rockets with, you will produce two molecules of O2 as well, one from the hydrogen and the other from the carbon.

The loss is negible small (closed system). You lose a tiny amount of water in a system with reclaimer due to plants spliting up a tiny amount to grow. And Oxygen you lose a small part due to it being made into Methan (and that is only if the theories and tests to directly split CO2 won't pan out). But fun fact Humans don't use that much Oxygen at all the real problem is to not get CO2 poisioned and that is what such a cycle system manages quite well. So for the first about 10 humans you get you just need the initial amount of water and oxygen and then a few litres per year (either as water or as oxygen). And while we are talking about potential loses in the closed system do they need to ship nitrogen from earth constantly because every EVA they will lose some (only a tiny amount but if that tiny amount is represented by the constant flow of water you need with oxygen and water on a level comparable to creating 100% non recycable rocket fuel you should need to get quite some nitrogen imports too).

Also oxygen wouldn't be a byproduct of creating rocket fuel, because in order to burn the hydrogen you need to put oxygen into the rocket too. There is no oygen in Mars atmopsphere, nor when you leave it. So just putting hydrogene into the rocket will result in a rocket just sitting there not ever lifting from ground. So if you connect the habs but barley use any water and oxygen with them but then had to fill a lot of both oygen and hydrogen into rockets that would make sense. But in the streams it seems the water the habs need is not negilible.

Edit:

Talking about Nitrogen made me think about fertiliser and thus look some stuff up. It seems there is Nitrogen. But only 2.7% of the atmophere (compared to the whooping 78% on earth) add that Mar's atmopshere is a lot thinner and getting it would be a lot more of a shore (I'm not sure about potentially otherwise bound nitrogen on Mars that migh be easier to get to). But once you have you initial amount it will be a neglegible loss in a closed Dome system again. The real problem will likley be phosphor. Other than the natrual recycle cycle we know of no way to restore that one and that cycle take forever and needs big biologial systems that you can't easily resproduce in constraint space. However there seems to be phosphor on Mars I'm just not sure how much and, if it is viable phosphor for fertiliser. Useing nightsoil is likley not an option given you have more than one colonist and the loss of phosphor still would not be sustainable (in fact currently the rate we use it is not sustainable here on earth either).

 

[keynes2.0]

The loss is negible small (closed system).

A perfect closed system has never been made. The ISS for instance only reclaims 93%. One part is that pee can't be perfectly dehydrated and the ammonia in pee contains a lot of hydrogen. Even if a colonist is only losing a quarter kilogram worth of water per day that really adds up in the 700 days between launch windows. A more advanced system could probably get that number even lower but that system would be bulky, creating a different mass tradeoff.

 

[Bob_Herzog]

The main reason the ISS can't recycle more is the environmentalt constraints though. A system that includes farming would be a lot better after all water gets recycled nearly perfectly in nature.

But even if we only assume 93% that would still not justify for the water use to be anywhere near of what is used to make rocket fuel. And for oxygen the amount used and lost is even lower. Most oxygen such a colony would actually consume would quite likley be rocket starts.

 

[EleventhAvenue]

The main reason the ISS can't recycle more is the environmentalt constraints though. A system that includes farming would be a lot better after all water gets recycled nearly perfectly in nature.

But even if we only assume 93% that would still not justify for the water use to be anywhere near of what is used to make rocket fuel. And for oxygen the amount used and lost is even lower. Most oxygen such a colony would actually consume would quite likley be rocket starts.

Yes, but to have each dome filled with people consuming 0.005 oxygen per hour instead of 2 isn't very interesting.
Why use water to create oxygen? Why does the ship only take 24 hours to from Earth to Mars? Why does everyone live in huge glass domes?
I find this an interesting subject to discuss, but if your question is why things are like they are in the game, I think the answer is pretty obvious.

 

[keynes2.0]

The main reason the ISS can't recycle more is the environmentalt constraints though. A system that includes farming would be a lot better after all water gets recycled nearly perfectly in nature.

That requires running at a water deficit for decades. Only 1% of the water on earth is useful to humanity. The rest of it is non-potable or frozen. That is the price of doing things naturally, your needs need to be balanced against the tiny amount that is decomposed, evaporated into the atmosphere and the precipitated downward. And on Mars, atmospheric precipitation is very close to zero. You can replicate evaporation and precipitation but then it isn't a natural cycle anymore, you are using machinery and that machinery will have mechanical wear that means you need filters, i.e. you are doing exactly what they are doing on the ISS and losing 7% to brine.

But the bigger problem is decomposition. Because you are talking about creating a mini-biosphere that means you have a lot of scrap bio-materials. That isn't the case on the ISS where they only send up food for human consumption, here you are going to have compost from all those plants you are using. The decomposition process on earth get's most of the hydrogen back from compost relatively quickly but not all of it. So that means every day a human is eating martian grown food and fully recycling it, you are putting hydrogen into the compost heap. You only achieve a balance of hydrogen once your compost heap grows so big that the daily release of hydrogen matches the rate that eating and plant waste adds to the hate. And where are you going to store that compost, what machinery will you use to reclaim the water released from it without messing up your habitat?

So before you can perfectly recycle your water, you need to spend a long time filling up a compost reclaimer with waste. The fuller it gets, the more you get but until you throw away enough hydrogen, you are running at a deficit. And where is that water going to come from? Well from ice.

 

[keynes2.0]

That's completely right. But I have a question. How much water do we need to generate O2? And is there enough water to create O2 for human?

It looks to me like you have some sort of unwanted plugin in your browser which inserted a spamlink.

As for your question, about 89% of water is oxygen so your oxygen production in mass terms will be just a bit under your water input in mass terms, minus whatever is lost to inefficiency.

 

[King Korihor]

I would like to point out that there are other ways to extract Oxygen. One of the legitimate sources of Oxygen I've seen in discussions about extra-terrestrial colonization is simply extracting it from rocks as you engage in reduction processes.... which release Oxygen as a by-product. Normally on the Earth when you are engaging in metal processing you are trying desperately to get smelting of stuff like Iron or even Aluminum into a mostly Oxygen-free environment unless you are deliberately using Oxygen to burn out common contaminates in Iron-Oxide ores like Carbon in the Basic Oxygen Process.

Mostly, some of the metal producing buildings in this game could be either consumers or producers of Oxygen as well and it doesn't need to be exclusively water as the only source or even primary source of Oxygen. Aluminum, Iron, and Silicon Oxides are found in large abundance on the surface of Mars and as a means to produce at least a starter supply of Oxygen.

As for your question, about 89% of water is oxygen so your oxygen production in mass terms will be just a bit under your water input in mass terms, minus whatever is lost to inefficiency.

That isn't quite true. Oxygen is only 1/3rd of water.... by volume. That is even where the famous formula of H2O comes from as it is two parts water to one part Oxygen. By weight Oxygen is about 16 times the mass of Hydrogen though, so if you are calculating the mass of the products produced from separating the atoms from something like electrolysis, it is indeed an 8:1 ratio of the mass of Oxygen to the mass of Hydrogen.

To me, getting breathable Oxygen from mining & smelting operations sounds like a far more efficient process where the Oxygen is a byproduct that otherwise would need to be literally vented into the atmosphere otherwise and thrown away as opposed to a purposeful destruction of a much more scarce resource (water) where additional energy is needed for its creation. As an emergency generation option to keep people alive and for use in vehicles or small spacecraft.... it certainly makes sense. For use on an industrial scale when other sources of Oxygen exist, it doesn't make quite so much sense. Hydrogen is also such a valuable commodity that simply venting it into the Martian atmosphere in such huge quantities also seems like an utter waste, particularly when it can be combined with the CO2 in the atmosphere to create Methane (extremely valuable as rocket fuel.... and has other uses as well).... a process that also produces Oxygen as a byproduct in significant quantities.

 

[keynes2.0]

That isn't quite true. Oxygen is only 1/3rd of water.... by volume. That is even where the famous formula of H2O comes from as it is two parts water to one part Oxygen. By weight Oxygen is about 16 times the mass of Hydrogen though, so if you are calculating the mass of the products produced from separating the atoms from something like electrolysis, it is indeed an 8:1 ratio of the mass of Oxygen to the mass of Hydrogen.

So..... exactly what I said then?

Hydrogen is also such a valuable commodity that simply venting it into the Martian atmosphere in such huge quantities also seems like an utter waste

Where is this venting H2 into space thing coming from?

 

[King Korihor]

Where is this venting H2 into space thing coming from?

Where is it being used in the game? I've only seen a few buildings so far, so it might be there... but I haven't seen it. What is the point of electrolyzing water if the Hydrogen isn't being used?

Also, on Mars with materials going through pipelines, the mass of the Oxygen is going to be almost immaterial and inconsequential. It is the volume that it takes up in storage containers that is by far more important.... and something which is done in the game with Oxygen storage facilities. If you can fill up a large storage container full of Oxygen, where did the Hydrogen go that was twice the volume of that same building?

 

[keynes2.0]

Where is it being used in the game?

In the only video I have seen, the water was being used for fuel and farming. In neither case is hydrogen being vented into space. AFAIK the oxygen is generated with the MOXIE which can be seen at moment 31:00 of the video from gamescon. That used power but didn't use water and didn't operate in dust storms so I'm guessing it electrolyzed atmospheric CO2.

 

[King Korihor]

The Let's Play video that I saw required the MOXIE to be placed immediately adjacent to a water generator/source in order to produce Oxygen and required water.... which is sort of the point of this whole thread. I watched Quill18's playthrough, and a developer (or PR rep.... I wasn't sure which) at his side actually said that water was essential to get it to work. If you saw another video which showed it standing on its own.... either that is a different version of the game or something might have been hiding.... or that feature hasn't been fully implemented yet. It does appear that water in the current version of the game is essential to making Oxygen for colonists at least as an intention of the developers.

I'm fine with some handwavy stuff and this game is definitely far from complete, so there might be some additional resources that show up in the future like Hydrogen or Methane. i also get that games are abstractions that sometimes have their own separate physics that doesn't quite make sense in the "real world". Mostly, I was trying to explain in simple terms how something other than water might be used as a generation medium for Oxygen and I hope something else is considered in the future.

 

[keynes2.0]

The videos dont actually show any water being consumed. Maybe it's a relic of some earlier draft of things. The MOXIE is the name of a real experiment and that experiment uses no ice.

 

[Voidlord]

Here is an idea...
It's a Game, so its abstracted...

 

[Orlunu]

Here is an idea...
It's a Game, so its abstracted...

So let's just have interdimensional unicorns eat the hydrogen and the colonists can breathe the waste gasses they produce.

No? But iz just gaem...

 

[keynes2.0]

The unicorns would have to be nuclear for them to turn hydrogen into breathable air.

 

[Xeorm]

They might only be venting the hydrogen as it's not a terribly useful gas for a beginning colony. From what I've seen there's not a huge rush to get fuel for the rockets early (if ever?) and that'd be the main usage of the gas for a beginning colony.

At the same time, water is fairly plentiful even on Mars, and ridiculously easy to break down if you have the electricity. Oxygen attached to minerals isn't quite as easy to grab and have be pure enough.

Plus, is a game where abstraction is key. Having materials with multiple requirements and outputs would be more realistic, but quite a bit more complicated. Oxygen from water is simple, what one would first expect, and reasonable. It works much better as a gameplay concept because of that.

 

[King Korihor]

They might only be venting the hydrogen as it's not a terribly useful gas for a beginning colony.

The Methane you can produce from hydrogen is also extremely useful as a base material for making more complex hydrocarbon molecules. You may only be thinking of gasoline or other common petroleum distillates, but this can be a stock material for plastic manufacturing too.

Robert Zubrin also demonstrated a methane generator that can literally fit inside of a suitcase and has a mass of only a hundred kilograms or so. That is something which could be packed up today and sent to Mars right now, which uses only water and CO2 as the source materials along with a modest solar panel as a power source. If that isn't an early starter technology for a beginning colony, I don't know what else you could offer.

There shouldn't be any problem with venting products that you aren't using immediately, just like I presume is happening with all of the resource generators in general. If there are additional products that a resource generator can produce and be unlocked from either mods or from research, it would be useful as a mid to late game feature to permit producing other kinds of things that might be useful.

BTW, I hope there are a few really complex multi-chain production cycles in this game. Bot manufacturing can and should be one of those that is a combination of water, minerals, and other sources that go through multiple steps.