I'm posting here because I wasn't sure what category this would fit in, so here's my question:
I read that water on the ISS is recycled, every last drop of it, down to the condensing of breath, which continuously supplies the astronauts with potable water.
That's fine.
But I also read that the main source of oxygen was from the electrolysis of water into hydrogen and oxygen, with the oxygen vented into the cabin and the hydrogen vented externally.
How on earth (or rather, off of earth) are they recycling water that gets split, then half inhaled and the other half ejected into space?