When the International Space Station's first permanent crew arrives next month, it will have to perform an unintended science experiment learning to fight mildew in orbit. If Russia's Mir space station is any indication, the astronauts will find space bugs are as common as the stink in an old sneaker.
"I'm sure there are some pathogens on the International Space Station already, because we've made no attempt to sterilize materials before sending them to the station. We don't consider it a problem," says Duane Pierson, head of the microbiology program at NASA's Johnson Space Center. But unwanted fungal passengers have made trouble aboard Mir, eating away at windows and destroying electronic equipment. "I think most of the difficulties on Mir have been due to localized areas of high humidity, because fungi and bacteria like to grow in wet places," Pierson says. "The International Space Station was designed to prevent condensation buildup." All food and water sent to the station will be screened for menacing microbes, and filters will scrub pathogens from the air.
One thing the crew won't be doing is spraying the $30 billion-plus space station with supermarket-variety antibacterial products. High radiation levels in Earth's orbit speed the rate of mutations, and spraying might just hasten the arrival of resistant strains. "For the most part, the crew will clean with regular surfactants plain old soap."