NASA astronaut Sunita Williams (center) and her Expedition 14 and 15 crewmates enjoy a light moment during a crew change ceremony aboard the International Space Station in April 2007. Clockwise from lower left are: Expedition 14 flight engineer Mikhail Tyurin, Expedition 14 commander Michael Lopez-Alegria, Expedition 15's commander Fyodor Yurchikhin and flight engineer Oleg Kotov. Credit: NASA.
