There are many occupational hazards in space travel. But Russian researchers have discovered a new one: meaner bacteria. Scientists launched colonies of bacilli and E. coli into space and found they undergo significant changes. And not good ones either. The bacteria became much more aggressive and started to eat space ship components. That’s because they began to produce unusual enzymes, probably because of exposure to cosmic radiation and the lack of gravitation. The study on board the Mir and Photon 2 spaceships found that the changes occur even during short flights of 10 to 14 days. The bacteria change size and shape and their DNA changes too. Some genes that are dormant on earth switch on, producing the enzymes. The researchers think that it’s also likely that the mutant bacteria could pose greater threats to astronauts, who already suffer from immune system problems in space. But there’s one piece of good news: when the bacteria return to earth the aggressive traits vanish.