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What is a virus?
There are creatures that were living on the
Space Station before the first astronauts went inside. Astronauts
found a few living on the Moon. Scientists believe they
could even live on Mars. These creatures can live almost
anywhere— they're living inside you right now! Where
do you think they came from?
It's not something out of a science fiction
movie. It's bacteria and other microbes, such as viruses
and fungi. These tiny microorganisms hitched a ride on pieces
of the International Space Station (ISS) when they were
launched.
Viruses are very small, visible only through
a special microscope. They can withstand extreme temperatures
and hostile living conditions, and to make matters worse,
dormant viruses need no energy.
Viruses are very simple — just pieces
of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)
inside a protective protein coating. The DNA or RNA from
a virus enters the cell that is under attack. This cell
is forced to make copies of the virus. Destroying the original
cell, the copied viruses break out, each looking for other
cells to hijack. It’s easy to see how quickly viruses
can spread.
While microbes are just another part of everyday
life here on Earth, they can be a much bigger problem on
the Space Station. They may even be more harmful to the
astronauts in space since spaceflight weakens the immune
system. This means that astronauts could be more open to
infection. Also, experiments have shown that bacteria grow
faster in microgravity than they do on Earth. Another problem
is the small area that the astronauts live in while in space.
The microbes that are brought up have nowhere to go, so
germs can easily be transferred back and forth between the
astronauts.
To reduce microbe-related problems, astronauts are tested
for infection before they begin their spaceflight. They
also try to cut down on exposure to germs before their mission
so they don't catch anything before their launch.
On the Space Station, equipment is used to
clean the air and water. This helps protect the Space Station
and the astronauts from microbes. Special paint and low
humidity also keep microbe growth at bay on the Space Station.
Despite these high-tech solutions, astronauts still have
to clean. ISS crew members regularly wipe surfaces on the
Station with cloths and disinfectant.
However, astronauts don't always try to get
rid of the bacteria. Some microbes are actually invited
guests! A Space Shuttle mission in early 2003 included an
experiment involving a common soil and water bacteria. The
experiment studied the effects of microgravity on the bacteria.
Even though this research is going on in space,
you'll benefit from it here on Earth! Next time you go to
the dentist, keep an eye out for space technology. A tool
used by the astronauts to fight microbes is now being used
by dentists. It decontaminates the water used in dental
instruments. It was first used in the Space Shuttle and
in space suits. The same technology may eventually help
bring safe drinking water to people around the world who
currently do not have any.
Visit the links below for more resources from
NASA:
Growing
Microbes in a Bag - To grow microbes in a bag.
Tag,
You're Sick! - To understand how the immune
system fights germs.
Interesting
Microbes - To distinguish between the four
main types of microbes, and to identify the parts of a bacterial
cell.
Ganging
up on Germs - To investigate the effect of
preservatives on the growth of bacteria.
Comparing
Viruses and Bacteria - To learn how viruses
differ from bacteria.
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