5. Parasites

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You would think that having parasites here on earth to plague both man and beast would be bad enough, but those ever-curious scientists wanted to know how they would survive in space. As a result, a batch of roundworms was sent along on space shuttle mission in 2003. Tragically, space shuttle Columbia broke up and disintegrated during its return trip to earth and all the astronauts perished. Oddly enough, the parasites all survived the disaster without a scratch.