Water requirements are extremely critical and the amount supplied should
not under any circumstances be kept to a minimum. Rather, a large margin
of safety should be allowed.
Present data on water requirements show a very strong dependence upon
suit inlet temperatures. In the absence of an accurately controlled suit
temperature, water requirements can easily double. If this should occur,
the mission would probably have to be aborted, since it is doubtful if
electrolyte balance would be maintained at such high rates of water
loss. Normal or even extreme conditions of the terrestrial environment
usually include diurnal variation in temperature which may modify water
needs. These conditions will not be obtained in the spacecraft.
In addition to ground-based experiments, measurements of water intake
should be made under actual flight conditions. Data from short-term
flights should be used for extrapolation to longer missions.