Catching a
free ride to Mars takes more than sticking out a thumb, but some hardy Earth
bacteria could survive as hitchhikers clinging to the outside of spacecraft,
studies have shown.
Now a set
of experiments going up with space shuttle Atlantis to the International Space
Station will test how exposure to the harshness of space might change bacteria
during a simulated
Mars mission.
"We
are interested in understanding what types of damage are induced in cells and
their DNA by exposure to space, what types of mutations may be induced, and how
these mutations might drive evolutionary adaptation to the extreme selective
environment of Mars," said Wayne Nicholson, a University of Florida
Institute of Food and Agricultural Sciences astrobiologist working from NASA's
Space Life Sciences Laboratory at the Kennedy Space Center.
Although
previous tests exposed different microbes to the space environment for up to
six years, Nicholson noted that the experiments mostly "tested whether the
bugs could survive long-term exposure to space" as opposed to seeing how
the bacteria changed in response to space radiation.
Bacteria
that can survive extreme environments interest researchers for several reasons.
Any Earth bacteria that escaped NASA's
"clean rooms" and took a trip to Mars might contaminate efforts
to find evidence of Martian life. Looking beyond, bacteria that can survive
long space journeys on comets or interplanetary shards also provide evidence
supporting the panspermia
theory that the seeds of life are everywhere and can survive hopscotch
trips from one space object to the next.
The current
shuttle experiment—a collaborative effort between the University of Florida,
NASA, the European Space Agency and the German Aerospace Center (DLR) in Cologne—will
take place for more than a year on an external space station platform called
EXPOSE. That platform will be installed outside of ESA's Columbus
laboratory module upon delivery by space shuttle Atlantis flight STS-122.
"Our
immediate goals right now are to hope for a safe launch and deployment, and to
work on our simulations and ground control experiments so that we will be
completely prepared for processing the samples when they return from Earth
orbit," Nicholson said.
advertisement
advertisement
