Recycling water is key for astronauts on the International Space Station since sending water to the crew is heavy and expensive. The current systems work well and the tech is being used here on Earth in places where clean drinking water is in short supply. In an effort to increase efficiency, astronauts will test a new filtration system from Aquaporin Space Alliance. The so-called AquaMembrane employs nanotechnology and proteins to transform waste water (sweat and urine) into clean drinking water, proteins that regulate water in living things like human kidneys and bamboo shoots. Those aquaporin proteins are situated on a membrane and as water passes through tiny protein tubes, an electrostatic charge stops things like salt from getting through. The water flows continuously from side to side without using extra energy thanks to forward osmosis.