12 bizarre things space travel does to the human body

This month NASA astronaut Scott Kelly hit an incredible milestone: He has spent more time in space than any other American in history.

Oct. 16, 2015, marked his 383rd total day spent zooming 250 miles above Earth aboard the International Space Station (ISS), beating astronaut Mike Fincke's previous record of 382 days, according to NASA. And on Oct. 29, he'll have spent 216 consecutive days in space, beating Michael López-Alegría's previous record of 215 days.

Astronauts are normally limited to six-month trips in space - but this is just the beginning for Kelly. He's spending a full, uninterrupted year aboard the ISS while his identical twin brother stays here on Earth. Scientists are studying both brothers to measure how the human body changes during long-term spaceflight. The brothers are routinely giving cheek swabs, blood samples, and fecal samples to researchers for analysis and comparison.

This year-long experiment could pave the way for a long-duration trip to Mars, but it is not for the faint of heart. Scientists already know a few things about what space and microgravity does to the human body over time, some of which are downright disturbing.

Keep scrolling to see some of the bizarre things that happen to the body in space.