3. Salmonella

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Why scientists picked a bacteria that has caused so much misery here on earth to send for a free ride into space in not entirely clear, but that’s exactly what they did in 2007. Samples of salmonella bacteria orbited for a total of 12 days. When it was returned to earth, it was found to be about three times more likely to call a person than it was before it left earth. The lesson seems clear. Sending bacteria into space might be a bad idea.