By
Dan Cassino
Arizona Daily Wildcat
'Aggressive' organisms on returning Mir have not caused problems in the past
When Russia's Mir space station falls into Earth's atmosphere this week, the most publicized danger is of one of the fiery pieces crash-landing in an occupied area.
However, when Mir lands on Earth, it may also bring with it a more insidious threat - fungi mutated by their long tenure on the 15-year-old spacecraft.
UA planetary sciences professor Jonathan Lunine, who has done research involving the detection of life on other planets, said the Mir fungus, however, is not a problem for Earth.
"It doesn't seem to be a really terrible threat," he said.
According to wire reports, Russia's Institute of Medical and Biological Problems has isolated aggressive fungi that have inhabited the inside of Mir's control panels and air ducts. The problem came to the attention of space officials when one of Mir's portholes was partially destroyed by a visible fungus colony.
NASA documents reveal that astronauts aboard the Russian space station were cognizant of the fungi and routinely wiped down the interior of the orbiter with specially-prepared fungicidal towels.
In a closed system, micro-organisms can develop differently than fungi that have been in normal circulation. On this front, however, Lunine said he doesn't believe that Mir presents a threat.
"I don't really think Mir is a closed system," he said. He pointed out that astronauts and cosmonauts have been coming onto and off of Mir for years, and wastes have been released. So far, none of these activities has brought back dangerous micro-organisms.
Associate research scientist Patricia Rusin, who teaches in UA's microbiology department, has more mundane concerns about the fungi.
"My primary concern is allergies," she said.
The increased amounts of radiation on the space station also fail to alarm Rusin, as fungi exposed to electromagnetic radiation on Earth have not become more dangerous.
"People have been using UV light as a disinfectant for years, and I've never heard of any problems," she said.
Even if the fungi mutated, Rusin said she doesn't believe that they would present a problem.
"(Mutation) is not a real danger - if they mutated, that would probably be a bad thing for them," she said.
Despite the fact that fungus on Mir doesn't present a danger to Earth, the issue raises concerns for the future of space exploration and the detection of life on other planets.
If landers sent to other planets to detect life are contaminated with terrestrial micro-organisms, scientists could incorrectly infer the presence of native extra-terrestrial life.
"There is a concern that if we send vehicles not properly sterilized, it could lead to a false-positive for life detection," Lunine said. "The chances are small, but not zero."
Lunine explained that tests exist to weed out known life forms from samples, and he suggested that these tests be utilized.
Rusin said there is a good possibility that fungi might be able to survive on long-term space missions.
"They don't need much in the way of nutrients," she said.
Anything containing carbon can feed the fungi, including plastic, adhesives and particles of human skin, Rusin said. Also, the spores of the fungi, which act like a plant's seeds, can survive for extended periods.
"The spores are very resistant - they can just rest as spores for years or months, just hoping that some nutrients show up," she said.
Furthermore, there is the possibility that extant life forms on other planets will be affected by contaminated Earth spacecraft.
"Probably, earthly bacteria have already been exposed to Mars," Lunine said.
In order to reduce the chances that extra-terrestrial ecosystems will be impacted by the presence of earthly bacteria, steps are being taken to ensure that spacecraft exploring the surfaces of Mars and Europa, a moon of Jupiter, are not contaminated.
Lunine explained that the Galileo spacecraft will not impact the surface, and missions to Europa are also designed not to impact - even though in the case of Europa, this could have a negative affect on the data gained from the project.
However, Lunine said that steps being taken today will probably guard against this possibility.
"There are valid concerns, and they have been dealt with," Lunine said. "NASA has been very responsive."
