NASA Astronaut Don Pettit Sets up for Science of Opportunity

iss072e098102 (Oct. 23, 2024) -- NASA astronaut and Expedition 72 Flight Engineer Don Pettit is pictured setting up one of his "Science of Opportunity" experiments aboard the International Space Station. For this specific experiment, Pettit grew thin wafers of water ice using the orbiting lab's freezer, and photographed them in front of a white, blank computer screen and polarizing filter to display the colorful fragments of ice crystals.