On long missions, water must be recycled and reused as much as possible. Dehumidifiers remove moisture from exhaled air. On space stations, this water is usually reused for washing. Eliminating body wastes. The collection and disposal of body wastes in microgravity poses a major challenge.
Astronauts use a device that resembles a toilet seat.
Air flow produces suction that moves the wastes into collection equipment under the seat. On small spacecraft, crew members use funnels for urine and plastic bags for solid wastes. While working outside the spacecraft, astronauts wear special equipment to contain body wastes. The simplest bathing method aboard a spacecraft is a sponge bath with wet towels. Astronauts on early space stations used a fully enclosed, collapsible plastic shower stall.