Most Shuttles are equipped with vacuum toilets that work a little like a vacuum cleaner!
Water cannot be used in the
weightless environment of space so, like wash basins,
toilets on the space shuttle can't use water. In a corner of
the shuttle's mid-deck there is a toilet for use by both men
and women. Although it looks like any other toilet used on
Earth, it is a little different. To make sure what goes into the
toilet doesn't come out, it is sucked away and then
vacuum-dried. The system is a little different depending on
whether the astronaut urinates or defecates. When urinating,
the waste is sucked away in a hose. But when defecating, the
toilet is used the same way as a normal toilet and the
astronaut pulls a lever to have the waste sucked
away.
Unlike on Earth, pushing alone does not allow the astronauts to defecate. Even when they do manage to get something out in a weightless environment, it often flies around the ship, gets stuck on bodies and other parts of the shuttle, or simply floats, meaning that astronauts need to have quite a bit of training before they can use shuttle toilets.
For the first astronauts, who were
only in space for a short time, the astronauts all wore
nappies and their waste was collected in bags and taken back
to Earth. Most astronauts were very unhappy with this
situation. But even now, during take-off,
re-entry or during a space walk, astronauts must wear
pressurized suits and can't use the toilet. That means they must wear either a
type of nappy, or have a bag to catch their
waste.