The problem of waste production is intimately related to nutrition and
can be solved or simplified by dietary changes. Any diet should be
adjusted for the minimum production of feces, before and during even
short flights. Water will be sequestered by accumulation in the feces,
and the net loss, under normal conditions, would be approximately 40 to
60 grams per man per day. Flatus can be a serious problem, since
considerable concentrations of toxic gases may accumulate. The
purification system for the recirculated atmosphere must be able to
remove these, although the diet should be planned to minimize the
problem. The collection of urine and its storage is of importance,
particularly on short-term flights, and individual packaging and
labeling of urine specimens will be necessary for the analyses.