In his off-duty time, NASA Astronaut Don Pettit experiments with the physics of
water in the weightless environment aboard the International Space Station. Published as a collaboration between NASA and the American Physical Society. Find more of these amazing videos in the following playlist.
Donald Roy Pettit (born April 20, 1955) is an American chemical engineer and a NASA astronaut. He is a veteran of two long-duration stays aboard the International Space Station, one space shuttle mission and a six-week expedition to find meteorites in Antarctica. As of 2018, at age 64, he is NASA's oldest active astronaut.
Definition from Wikipedia – Donald Pettit