- Now that the Zvezda service module has docked and the
International Space Station will soon be habitable, a growing number of
cosmonauts and astronauts could soon face a new threat -- space
fungus.
-
- During a recent mission, Mir crew members noticed that
the view from the station's porthole was deteriorating due to an unknown
film that was spreading like some horror-movie scum.
-
- "During 20 years of research, the IBMP scientists
have discovered up to 250 species of microorganisms which live inside
manned
spacecraft, including fungi and bacteria." Elena Deshevaya, an IBMP
researcher
-
- The porthole was examined carefully after the crew
returned
to Earth, with the results shocking researchers and engineers. Although
the porthole and other windows were made of extra-hard quartz glass and
mounted on titanium covered with enamel, they were partly destroyed by
a colony of fungi and bacteria visible to the naked eye.
-
- A communications device on Mir was damaged by space fungi
during the 24th main mission.
-
- Engineers later learned that the fungi also damaged
electronic
equipment on Mir, including a control block for a communications device
used on the outpost from 1997 to 1998 during the 24th main mission to
Mir.
-
- The microorganisms crept under the steel cover of the
block and sat on electrical contacts and polyurethane pieces. As a result,
parts of copper cables located nearby also were oxidized.
-
- Subsistence for the microorganisms was certainly not
the metal, glass and plastic of those devices, said Natalia Novikova, a
deputy chief of the Department at the Institute of Biomedical Problems
(IBMP) in Moscow.
-
- "They consume organic stuff which consists of skin
epithelia, lipids and other products of human activity," Novikova
said. "These products get into the station atmosphere from human
breath,
sweat etc.and stick to the station's surfaces."
-
- "Bacteria and fungi eat this stuff and generate
products of metabolism, particularly organic acids which can corrode steel,
glass and plastic."
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- A Mysterious Strain
-
- The IBMP has been on the trail of space microorganisms
since 1980, when the crew of the fifth main mission to the former Soviet
Union's Salyut 6 space station found a white deposit on parts of the
station's
interior and exercise machines.
-
- Samples of this deposit were delivered to Earth. Having
examined them, IBMP researchers determined that the deposit was left by
Aspergillus, Penicillium and Fusarium.
-
- The unwelcome visitors made it to the Salyut 7 station
as well. In 1985, the crew members of the last mission to this station
were alarmed by fungi destroying the inner plastic surfaces of panels
covering
the walls of the orbital outpost.
-
- "During 20 years of research, the IBMP scientists
have discovered up to 250 species of microorganisms which live inside
manned
spacecraft, including fungi and bacteria," said Elena Deshevaya, an
IBMP researcher. "107 species of fungi were found onboard Mir. The
most frequently met fungus is Penicillium chrysogenum."
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- More Fungi From Beyond
-
- Not only do space microorganisms thrive inside
spaceships,
but they actually procreate there. Some fungi found inside Mir in 1995
were descendants of the fungi discovered in the station in 1988, Novikova
said.
-
- "All the space microorganisms found inside
spaceships
originated on Earth," she said. "Most of them got into spacecraft
on Earth and some of them were brought aboard with the visiting crews.
So, you would expect them to behave like 'normal' Earthly fungi and
bacteria."
-
- This is not the case, however. Microorganisms in space
significantly mutate. One of the reasons for their mutation could be the
level of radiation on Mir, which is 500 times more intense than on
Earth.
-
- "Fungi and bacteria are dormant for a number of
years and than suddenly become active. Then they may become passive again,
but overall their aggressiveness exceeds this of the same type of
microorganisms
on Earth," said Novikova.
-
- "We don't know what triggers their activation in
space," Novikova said. "Based on some observations we can say
that the older the plastic is, the more likely it will be used by
microorganisms
as their feeding ground. They also become more aggressive after the
increase
of solar activity."
-
- Storing Fungi
-
- All the samples of space-grown microorganisms brought
back to Earth are kept at IBMP in sealed ampoules stored in safe places.
"We don't know how they will behave if they get back into regular
Earth conditions," Novikova said.
-
- There is one more reason, however, for keeping space
mutants in specially secured places. "If you take a space-grown
microorganism
which used metal as a part of its habitat and keep cultivating it by
increasing
the content of metal in its habitat, you can potentially get a destructive
biological weapon which will literally 'eat' arms," said
Novikova.
-
- Preventing Future
Outbreaks
-
- A number of precautionary measures have been taken to
minimize the risk of spacecraft contamination.
-
- All cargo destined to go to a space station is carefully
disinfected. A spacecraft is often filled with a gas mixture of ethylene
oxide with methyl chloride that is lethal to microorganisms. A few days
before launch, public access to cosmonauts is severely restricted to avoid
possible transfer of microbes to the crew.
-
- During flight, the crew vacuum-cleans the station once
every two weeks and wipes the outpost's surfaces with special wet
disinfecting
cleaners. Mir also has a special equipment that cleans the station's
atmosphere
of microorganisms.
-
- IBMP also has developed "Fungistat" which has
proved to be an effective killer of fungi.
-
- A metabolic product of space fungus created a small
hollow
in this aluminum piece of space equipment
-
- Such precautions bring their fruits. "None of Mir
crew members has ever got any infectious disease in space," stressed
Deshevaya.
-
- But even the most effective disinfecting measures, like
filling spacecraft with an extremely toxic gas mixture, do not kill all
the fungi and bacteria.
-
- "Microorganisms get inside plastic where this
mixture
cannot reach them. Than at some point during flight, the contaminated
plastic
just emits its inhabitants into the station's atmosphere," said
Novikova.
-
- It Came From the United
States
-
- The upcoming international operations on the ISS present
extra challenges for microbiologists.
-
- "Space-shuttle crews brought some microorganisms
to Mir which had not been found aboard the station before, particularly
Penicillium expansum," Novikova said. "This is quite natural,
taking into consideration the peculiarities of [the] U.S.' environment.
There is a greater variety of fungi and bacteria in a warm climate than
in a cold one, like in Russia."
-
- Novikova totally agrees with the strict measures adopted
by NASA to avoid possible contamination of Jupiter's moon Europa by robotic
spacecraft.
-
- "Regular and relatively harmless microbes can
dramatically
change their characteristics in extraterrestrial conditions. For this
reason
the Russians thoroughly decontaminated the Mars 96 spacecraft before
sending
it to Mars," said Novikova
-
- Deshevaya said that decontamination was done for the
sake of future human missions to Mars. "We don't want future Mars
voyagers to bring back to Earth mutated microorganisms which could pose
a potential threat to humanity," she said.
-
- "With the International Space Station and future
human mission to Mars in view," Novikova said, "it is especially
important to study space microbiology."
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