A steady flow of air moves through the unit when it is in use, carrying wastes to a special container or into plastic bags. The container can be opened to vacuum, which exhausts the water and dries the solids, and the plastic bags, when used, can be sealed. Some of the wastes may be returned to Earth for postflight laboratory analysis. In the past, such analyses have helped doctors understand how the body functions in microgravity, including data on which minerals the body loses in unusual amounts. Unlike Skylab, which had an enclosed shower, Shuttle travelers can only take sponge baths in space.
Water droplets float about in weightlessness, creating a potential hazard for electrical equipment.
Water is obtained from a handgun, where the temperature can be set at any comfortable level from 65 to 95 degrees F. Dirty water from the sponge is squeezed into an airflow system which conveys it to the orbiter's waste collection tank. Whiskers cut in shaving could also become a nuisance if they floated about, with a potential to damage equipment. Male astronauts can avoid this problem by using conventional shaving cream and a safety razor, then cleaning off the face with a disposable towel. Engineers have drawn on the experience gained in earlier manned space flight programs to plan sleeping and sanitary arrangements for the Space Station that will be more like those on Earth.