Because storing large amounts of waste
in a spacecraft would use up a large amount of space and also increase
weight, waste is recycled as much as possible. Everything must be
extremely clean in space, because the risk of diseases increases as
a result of confinement and exposure to microbes in microgravity.
Because the cargo space of a spacecraft is limited, waste products
must be recycled as much as possible. Wastes can arise from eating,
cleaning, and working. Proper hygiene in space serves not only as
a psychological comfort but as a safety precaution as well. Studies
indicate that microbes can reproduce quickly in microgravity, and
because germs can transmit illnesses that can infect the entire
crew, everything must be as clean as possible.
People, filters, and other various surfaces acquire dirt and require
cleaning. Wet trash has its water filtered and removed for reuse.
Other types of trash can be burned, yielding substances such as
carbon dioxide and water. The carbon dioxide can then be converted
to water as well. Trash is stored in bags that are stowed in the
lower deck and disposed of on Earth. The conservation of useful
material from waste is beneficial in that it reduces the amount
of waste that must be stored for disposal on earth and increases
the supply of other useful products.