Using Water

Personal hygiene is a matter of considerable interest to everyone on board. Water, heavy to transport from Earth, is precious. For this rea­son, all water in space is recycled. The space station recycling system cleans and reuses wastewater from hydrogen fuel cells. It also condenses water from humidity in the air. The space toilet works on a suction system to remove waste, and urine is recycled (solid waste is stored and removed with the garbage). Even animals, such as labo­ratory rats taken into space for research purposes, help in the recy­cling regime: seventy-two rats can provide as much recycled water, from their urine, as one astronaut! Recycled “space water” is cleaner than the water coming out of a faucet in the United States.

To reduce waste, water pressure onboard the ISS is only half that found in a standard bathroom or kitchen on Earth. Astronauts wash their hands by wetting a washcloth

with a spray nozzle, and then using the cloth. They normally bathe every day after exercising, showering in a special economy shower unit. A space station shower uses less than 1 gallon (4.5 liters) of water, compared with an average of 11 gallons (50 liters) used by a person showering on Earth.