"Space station science officer Don Pettit always looks forward to Saturday mornings.

Like the other members of the International Space Station's 3-person crew, he's busy most of the week doing research and building the ISS, where he's been living for the past three months. "Saturday is when we have a bit of free time," Pettit says. Some of the crew read books, play musical instruments or watch movies. "I prefer to do 'Saturday Morning Science'--fun experiments of my own design. It helps me keep my mind off the possibility that similar tiny baggies may be used to collect my remains should a re-entry accident occur."