# A futuristic oxygen storage system for space suits? **URL:** \ **Category:** Factual Questions\ **Created:** [December 5, 2012, 6:58pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105 "2012-12-05T18:58:49Z")\ **Posts on this page:** 18\ **Page:** 3
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [December 7, 2012, 7:58pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/41 "2012-12-07T19:58:37Z")
Maybe you can incorporate a Philodendron in the space suit somehow? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 7, 2012, 8:59pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/42 "2012-12-07T20:59:45Z")
> [@](#): > > Quoth **dracoi** : > > For another thread on metabolism, I calculated that the average person is exhaling something between 500-1000 pounds of CO2. The oxygen content of that is something like 70% (32/46). The range in weight obviously depends on the person’s weight and activity level and could easily be much higher for an astronaut in a demanding environment. That’s per day? That can’t be right. That would mean that a person is expelling 150-300 lbs of carbon per day. All of that carbon would have to be replaced by food, and even if you assume that food is pure carbon, nobody eats hundreds of pounds per day. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [December 7, 2012, 9:08pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/43 "2012-12-07T21:08:24Z")
Yes, that does not sound right. Actually it sounds high for the total amount of gases exhaled. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [December 7, 2012, 9:28pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/44 "2012-12-07T21:28:29Z")
> [@Chronos](#): > > That’s per day? That can’t be right. That would mean that a person is expelling 150-300 lbs of carbon per day. All of that carbon would have to be replaced by food, and even if you assume that food is pure carbon, nobody eats hundreds of pounds per day. From **Great Antibob** ’s number - we consume about 550 liters of pure gaseous O2, a day. Assuming the 550 liters are at STP, that translates to 550/22.4 ~ 25 g-moles of O2. If all the O2 consumed went to form CO2, then we would have exhaled 25 g-moles of CO2 or we would have exhaled 25 g-moles of Carbon which is the same as 300 grams of Carbon or 0.7 lb of Carbon ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [December 8, 2012, 6:23am UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/45 "2012-12-08T06:23:30Z")
We sure do like to come up with clever ways to solve technical problems, when it’d probably be much simpler and cheaper to just distribute pressurized O2 into a honeycomb network of pouches along the arms, torso, legs, boots, head, etc., and avoiding the jointed areas in the suit. Slip on the skintight suit, attach your helmet, hook up to the ship’s O2 hose to fill up and pressurize the suit, and you shouldn’t need the heavy steel tank since each cell would probably have a much lower PSI, than trying to hold the entire volume in one single container. ---
**Author:** ![Floppyhatmike](https://avatars.discourse-cdn.com/v4/letter/f/3ec8ea/32.png) [@Floppyhatmike](https://boards.straightdope.com/u/Floppyhatmike)\ **Post date:** [October 3, 2023, 7:56am UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/47 "2023-10-03T07:56:30Z")
With all the leaps people are talking with tech that not available at this point in time. Why not use a similar tech to the abyss and use a breathable liquid to not only pressurize the suit but also provide all the O² needed. Which then could be pases through a scrubber to remove any CO². several advantages to this approach since wouldn’t need to provide heat or cooling to the suit the breathable liquid could be warming or cooled to the appropriate temperatures. And while were at it use nanotechnology to increase the body ability to store and provide O² to the cells in the body thus extending time that would be needed to breathe from seconds minute(s) if at rest to hour+ active. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 3, 2023, 8:30am UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/48 "2023-10-03T08:30:51Z")
> [@Floppyhatmike](#): > > a similar tech to the abyss and use a breathable liquid to not only pressurize the suit but also provide all the O² needed. The problem with the tech featured in The Abyss is that it doesn’t solve the supply of oxygen or the logistics of scrubbing. It just provides a transport mechanism that works at high pressures. The commentary above is dealing with the long term question of how to carry enough oxygen and enough scrubbing capacity to last multiple days. My comment is that all the worry about how to eject carbon from the cycle is misplaced. The entire problem is one of how to power a human being over an extended period. Humans, just like about every other living thing on the planet, run the Krebs Cycle. We turn glucose and oxygen into ATP and carbon dioxide, with water on the side. The whole problem is to supply the human with oxygen and glucose. We don’t want to eject carbon from the cycle. We want our suited human to eat it again in a useful form. So the science fiction suit has a power pack that drives a process to reverse the ATP energy cycle and regenerate glucose from the expired carbon dioxide. Probably reprocessing available water into the system as well. The power needs are relatively modest, especially if we allow some useful progress in technology to match our suit wearer’s use case. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [October 3, 2023, 1:07pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/49 "2023-10-03T13:07:31Z")
A human requires a bit less than 1kg of oxygen per day, which you can get in roughly 1kg of water. You can electrolyze 1kg of water with about 5kWh of electricity, using current technology. 5kWh of energy is contained in about 15% of a gallon of gasoline, which weighs about 0.5kg. If we assume a fuel cell with 50% efficiency, that means 1kg of gasoline (or similarly energy dense fuel) per day. So, one would need about 2kg of consumable and easily transportable/storable liquids per day plus the equipment needed to generate electricity / electrolyze water / capture exhaled gases, in order to get 24hrs of usable oxygen. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 3, 2023, 5:12pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/50 "2023-10-03T17:12:20Z")
> [@TriPolar](#): > > The Russian’s emergency oxygen supply was special candles that were burned to produce oxygen. I forget the compound, but it’s been used in an old welding system. Great for long term storage I guess, but seems unlikely as most compact way to store oxygen. Sounds like oxygen candles: > **[Chemical oxygen generator | Oxygen candle](https://en.wikipedia.org/wiki/Chemical_oxygen_generator#Oxygen_candle)** > > A chlorate candle, or an oxygen candle, is a cylindrical chemical oxygen generator that contains a mix of sodium chlorate and iron powder, which when ignited smolders at about 600 °C (1,112 °F), producing sodium chloride, iron oxide, and at a fixed rate of about 6.5 man-hours of oxygen per kilogram of the mixture. The mixture has an indefinite shelf life if stored properly: candles have been stored for 20 years without decreased oxygen output. Thermal decomposition releases the oxygen. The burn... O2 candles are used on submarines to manage O2 levels. According to that article, the one used in spaceflight is a Vika oxygen generator: > **[Vika oxygen generator](https://en.wikipedia.org/wiki/Vika_oxygen_generator)** > > Vika or TGK is an oxygen generating system for spaceflight. It is a SFOG, or solid-fuel oxygen generator, a kind of chemical oxygen generator. It has been used on the retired Mir space station and the International Space Station. It was originally developed by Roscosmos to supplement the Elektron oxygen system on Mir. A Vika module, also known as a "candle", contains about one liter of lithium perchlorate and can provide oxygen for one person for 24 hours. > After being adopted for use on the ISS,... ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 3, 2023, 5:45pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/51 "2023-10-03T17:45:24Z")
> [@Great\_Antibob](#): > > From the first [google link](http://health.howstuffworks.com/human-body/systems/respiratory/question98.htm) (so chunk of salt with it, of course), a person breathes about 11000L of regular air, or about 550 liters of pure gaseous O2, a day. Not sure if it’s included in the calculations already here; the air we inhale contains about 21% oxygen but when we exhale, that breath still contains about 15% oxygen - that is, each breath is only consuming about a quarter of the oxygen in the air. That matters for breathing the same air over and over in a confined space because partial pressures and whatnot will probably make it harder for our bodies to extract the remaining oxygen, however in terms of your calculations on how much we need to pack for a day in some hypothetical spacesuit, it matters more. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [October 3, 2023, 6:15pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/52 "2023-10-03T18:15:05Z")
Yes the calculation includes just the part consumed, which ends up being ~100 gallons or ~500 liters or so, i.e. we process closer to 400 gallons a day. Big error bars, of course, because lots of factors involved in how much O2 we need. That said, wow, that’s from over a decade ago. Zombies still rot so there has to be some oxygen consumption, I suppose. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [October 3, 2023, 7:20pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/53 "2023-10-03T19:20:45Z")
> [@Cheesesteak](#): > > A human requires a bit less than 1kg of oxygen per day, which you can get in roughly 1kg of water. You can electrolyze 1kg of water with about 5kWh of electricity, using current technology. 5kWh of energy is contained in about 15% of a gallon of gasoline, which weighs about 0.5kg. If we assume a fuel cell with 50% efficiency, that means 1kg of gasoline (or similarly energy dense fuel) per day. > > So, one would need about 2kg of consumable and easily transportable/storable liquids per day plus the equipment needed to generate electricity / electrolyze water / capture exhaled gases, in order to get 24hrs of usable oxygen. Hmmm… and you produce hydrogen when you electrolyze the water, which ccan then be fed into the fuel cell to generate electricity. But fuel cells basically “burn” carbon or hydrogen (catalyst reaction?) meaning they need oxygen too. I think batteries are the way to go, at least until we get the thumb-sized fusion reactors from Asimov’s _Foundation and Empire_ ? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 3, 2023, 7:34pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/54 "2023-10-03T19:34:38Z")
Oh, sorry about that. I keep forgetting to scrutinise the dates on threads ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [October 3, 2023, 8:13pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/55 "2023-10-03T20:13:42Z")
> [@md-2000](#): > > But fuel cells basically “burn” carbon or hydrogen (catalyst reaction?) meaning they need oxygen too. Of course! Bah, there goes the plan. I looked up 5kWh batteries and they weigh about 100lbs, which suggested a fuel alternative that I clearly botched. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 4, 2023, 1:21pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/56 "2023-10-04T13:21:11Z")
I’ve never seen a picture of what they were using in space so it’s not clear what configuration it was. I had a [SolidOx](https://en.wikipedia.org/wiki/SolidOx_(welding)) welder that used sodium chlorate sticks to produce oxygen. Not that great at welding but the oxygen supply was sufficient to could cut thin steel. ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [October 8, 2023, 2:22pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/57 "2023-10-08T14:22:37Z")
Here is an interesting description of the O2 production on the ISS. Turns out they both produce O2 from H2O and produce H2O and CH4 from CO2. The production of H2O from CO2 isn’t quite enough to produce the necessary O2 so it requires the importation of some H2O, but it is almost a closed system. The methane is vented to space. > **[Breathe deep: How the ISS keeps astronauts alive](https://www.cnet.com/science/breathe-deep-how-the-iss-keeps-astronauts-alive/)** > > Shipping enough air to the International Space Station from Earth to keep the astronauts alive would be a costly business. Here's what they do instead. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [October 8, 2023, 3:23pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/58 "2023-10-08T15:23:37Z")
If you can use H2O as a source of oxygen for life support, then you could find plenty of water ice on most of the cold moons of the Solar System, and on Pluto. The chemical processes that produce oxygen from water would produce a lot of heat, but this would be useful on these cold worlds as a way of keeping warm. Even so, the excess heat might be tricky to get rid of, since most of these worlds are surrounded by insulating vacuum, so the heat would most escape though your boots and you’d end up standing in a soggy puddle of meltwater. All this assumes a lightweight source of energy that can be carried around easily - and is not horribly radioactive. I’m open to suggestions there. Mars is too dry to make in-situ resource utilisation an easy task, and Venus is far too hot to allow a lightweight suit of any kind (you’d need a huge refrigeration pack). ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 8, 2023, 3:30pm UTC](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105/59 "2023-10-08T15:30:21Z")
I would think the solar cells in the ISS could power a lot of electrolysis and combining using the excess hydrogen to combine with CO2 is a bonus with that method. Anyone know if using H2O2 has been considered to produce oxygen? It’s dense storage of oxygen in combination with water, easily broken apart into its components. It could also fuel rocket motors if needed. Does not eliminate CO2 though. It also produces a good bit of heat in the reaction which may be unneeded, and possibly undesirable. I think it might be more useful to use on submarines where the heat might be useful. [Previous page](https://boards.straightdope.com/t/a-futuristic-oxygen-storage-system-for-space-suits/643105.md?page=2)