NASA just recycled 98% of all astronaut pee and sweat on the ISS | Hacker News Reader

NASA just recycled 98% of all astronaut pee and sweat on the ISS

space.com

60 pointsohjeez20 comments

That 2% is still a big cost. I think In-Situ Resource Utilization is what we need to make it cheap enough to do more in LEO.

I know it's insane but mining water in space and sending it back to earth seems to be one of the best options.

Edit: If you're down voting can you let me know why?

I don't think it's insane at all, you raise a good point. There's a lot of H2O out there and it's a lot less energy to get it from ~the asteroid belt to Earth orbit than from Earth ground to orbit. Obviously we're not there yet from a technology or logistics standpoint, but I'm sure it's in humanity's future.

Shape it into space concrete aka pykrete by adding long fibers made from silicon.

I remember reading about space mining and the first target is ice to haul back to orbit for water. It was something I didn’t think about but makes sense because water is so heavy to get into orbit.

I agree, but I don’t think it makes as much sense for the time scale of the ISS since IMO by the time asteroid mining is successful, the ISS will be towards the end of its life. I think this is something that would be more worth putting in the general mission plan of an ISS successor or Gateway.

> That 2% is still a big cost

They can use it as fertilizer.

What is the time period? Is that 98% per day, per month, etc? If there is a loss of 2% a day, then in a month, about half is lost.

Put one gallon of urine in, get 98% of a gallon out I presume.

One step closer to stillsuits

Can't wait for the Apple Stillsuit Pro that matches their headset, and lets you drink your iWee.

Where does the last 2% of the water go?

It sounds like it gets stuck in solution.

Can you be more specific?

Unless you get the urine and sweat both down to solids, there is going to be some water in it. Granted, very, very concentrated urine and sweat (salts, urea, etc...) but it will still be in solution.

Getting that last 2% of water out of the solution to leave a completely anhydrous substance gets energy expensive. Also, some things are better left in solution (ammonia for example) making them easier to move around and deal with.

Is there a reason you can’t distill/evaporate the remaining water out of the solids?

How much energy are you going to expend to do that - and do things like separate the ammonia from the water?

It's not "it can't be done." It's a "it gets prohibitively expensive on a limited energy budget."

Note that you're going to be left with things like anhydrous ammonia when you're done. That is more difficult to work with than concentrated ammonia in solution. In a sealed environment, this becomes even more of a concern.

The ISS vents methane.

If you are interest in hearing from some experts on this topic:

https://www.youtube.com/watch?v=EwMpt2ZP-qA

Space plants using urine for water plus air capture would also do the trick.

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