Space station experiment to test bacteria hitchhiking to the Red Planet (12/10/2007)

If a trip to Mars seems like it would be a tough journey, imagine what it would be like on the outside of the spaceship.

Earth bacteria can be extraordinarily tough - rugged enough, in fact, to survive on the outside of a space capsule. Now, a set of experiments on their way to the International Space Station via this week's scheduled shuttle flight is designed to test exactly what effect the rigors of space could have on bacterial spores on a Mars-bound vessel.

"We're pretty sure that it's possible that this life could survive out there - but exactly how possible? And what happens to it if it does?" 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.

One of the biggest benefits of knowing how bacteria are affected by space could be to know when a space-altered bacterium is found on Mars. Even though all Mars landers are meticulously cleaned and disinfected before launch, researchers are hopeful the data from Nicholson's experiment will allow them to anticipate any possible contamination of life-detection equipment aboard future landers.

Bacterial spores have been shown to survive on satellites that had been in orbit as long as six years. Some of Nicholson's previous research has shown that bacterial spores could theoretically survive on bits of rock thrown into space after a large meteor strikes the Earth. It is even possible that the planets have been swapping organic material and even living organisms through such cosmic shrapnel.

As far as near-term human space exploration goes, the chance of this natural exchange is probably of little concern. However, the statistical likelihood has increased with humanity's ability to send its own packages to other worlds.

"It might be pretty unlikely, but one of these spores could hitchhike the distance to Mars on the surface of one of these devices and then could find its way into the sample," Nicholson said. "It would be important to know that we were detecting genuine citizens of the Red Planet, and not merely accidental terrestrial contaminants of our equipment."

Nicholson is working with a spore-forming bacterium known as Bacillus subtilis. His experiment is one of several being conducted on an external platform called EXPOSE, in collaboration with NASA and researchers at the German Aerospace Center (Cologne, Germany) and the European Space Agency (ESA).

The EXPOSE platform will be installed by spacewalk outside of ESA's Columbus laboratory module when it is delivered to the International Space Station on shuttle Atlantis flight STS-122, scheduled to launch Thursday.

Living samples of several microorganisms will be exposed to space for more than a year, returned to Earth and tested for survival, genetic and physiologic changes induced by space exposure.

Space isn't just a big, cold vacuum. From under the safe blanket of our atmosphere, Earth creatures are protected from the intense forms of radiation streaming from our sun.

Still, bacteria aren't your typical earthlings. Some bacteria can enter a form known as a spore, in which they shut down their metabolic processes while creating a thick shell.

In this form, they can stave off extreme temperatures and even high levels of harmful radiation.

"Life has all sorts of tricks up its sleeve," Nicholson said. "I can't wait to find out what it comes up with."

To learn more about Nicholson's previous experiment, visit: http://weboflife.nasa.gov/slstp/tovy.htm.

Note: This story has been adapted from a news release issued by the University of Florida

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