Is there any way to artificially make salts for humans colonizing planets on a long term basis?

It is given that the exoplanet has a water source. So do we hope for the best that it has salt present or should we make new sources?

  • $\begingroup$ Is there really such a thing as "artificially making salts" or making sources of salt? Can you add something to your question to describe what that means? Thanks! $\endgroup$
    – uhoh
    Sep 25, 2021 at 16:33
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    $\begingroup$ not to my knowledge so I was hoping i would get some ideas here!!, I had been tasked to find ways to colonize an exoplanet and find methods to make a sustainable city. It suddenly occurred to me that salt, which is an essential cooking ingredient may never be in that planet. So i was hoping anyone would guide me on finding newsources or substitutes for table salt. $\endgroup$ Sep 25, 2021 at 17:14
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    $\begingroup$ Okay I see. So start with human nutrition, check a list of nutrients, even a bottle of multivitamins. We need things like chloride and iodide (negative ions) and sodium, phosphorus, magnesium and a whole heck of a lot of calcium (positive ions). We also really like to eat sodium chloride in our food. You need to find all of those elements (and more), but these don't disappear when we eat them, they can be recycled from our waste. Too much calcium in astronaut pee almost shut down the ISS in the early years! $\endgroup$
    – uhoh
    Sep 25, 2021 at 17:19
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    $\begingroup$ @uhoh yep. Human waste is an excellent source of salts, indeed in any real longterm recycling system (even groundbased biological ones), it is the excess accumulation of such salts that tend to become a problem, not their shortage. Earth uses rain runoff to dump our excess salts in the Ocean, and whoo-boy there is a lot of salt that has already been disposed of that way. $\endgroup$ Sep 25, 2021 at 17:22
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    $\begingroup$ Sodium & chlorine are both reasonably abundant elements. See en.wikipedia.org/wiki/Abundance_of_the_chemical_elements which has several useful tables & charts. $\endgroup$
    – PM 2Ring
    Sep 25, 2021 at 19:47

1 Answer 1


It depends by what you mean by salt. Do you just want sodium chloride (NaCl) and maybe potassium chloride (KCl) or do you want the full range of salts, that also included sulfates, chlorates, perchlorates, nitrates, etc.?

Including on Earth, salts also occur on Mars (also, 1 and 2) and Ceres.

Both Earth and Mars have undergone significant weathering which includes the dissolution of minerals in water and subsequent precipitation of salts of various forms.

Any planet that has undergone a process of weathering and has had or still has large quantities of water will most likely also have natural salt deposits whether in oceans, salt lakes/basins or buried underground.

In these situations it would be a matter of finding the deposits and mining them or if they are still aqueous evaporating the water to obtain the salts.

To manufacture sodium chloride all that is required is equimolar amounts of hydrochloric acid and sodium hydroxide. Both these chemicals are dangerous and need to be treated carefully. Obtaining naturally occurring salts would be a better option.


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