The unexpectedly calcium-rich urine of International Space Station astronauts is causing major headaches for NASA engineers. The calcium is clogging the station's $250 million water recycling system and engineers are trying to come up with a fix in time for the Endeavour shuttle's trip to the International Space Station next month, Reuters reports.
The system worked fine when it was tested on earth, say engineers. They believe astronaut's urine may be so high in calcium because of the loss in bone density suffered by people living in zero gravity. "We've learned a lot more about urine than we ever needed or wanted to know," said station flight director David Korth. (More astronauts stories.)