From
http://history.nasa.gov/SP-400/ch5.htm<p /><br /><br />"Kerwin also had kind words about the functioning of Skylab's toilet.<br /><br /><br />"We owe our greatest appreciation to the people who designed it," he said. "It has worked much better than anticipated, and it has been essentially trouble free and not terribly time consuming."<br /><br /><br />The Skylab toilet, designed to function in the weightless environment, bore little resemblance to that found in home bathrooms. It was designed so that crewmen could eliminate body wastes through the necessary acts of urination and defecation. But it also supported biomedical experiments by sampling and preserving certain body wastes and disposing of the remainder. The entire system included a fecal-urine collector, collection and sample bags, sampling equipment, odor control filters, and a fan. The toilet was mounted on the wall rather than the floor of the bathroom, in the crew quarters area.<br /><br /><br />Defecation in space was complicated by the absence of gravity to move waste material away from the body. On Skylab, a hinged, contoured seat provided access to the mesh liner into which the astronaut inserted a fecal collection bag. Air was drawn through the fecal bag from holes in the seat and exhausted through the bag's vapor port, through the mesh liner, into the fecal collection receptacle, and then through a filter, where odors were removed, before it was recirculated into the cabin by a fan. <br /><br /><br />To use the toilet for defecation, the crewman sat on the contoured seat, then fastened a belt across his lap to hold himself securely in position. Handholds and foot restraints allowed him to maintain a sufficiently tight seal on the seat, as airflow from the fan separated the fecal matter from his body and deposited it in the fecal collection bag. A separate fecal bag was used for each defecation.<br /><br /><br />The crewmen could urinate from either a standing or