NASA astronaut Sunita Williams participates in the mission s third session of extravehicular activity EVA.

NASA astronaut Sunita Williams, Expedition 32 flight engineer, participates in the mission?s third session of extravehicular activity (EVA). During the six-hour, 28-minute spacewalk, Williams and Japan Aerospace Exploration Agency astronaut Aki Hoshide (visible in the reflections of Williams? helmet visor), flight engineer, completed the installation of a Main Bus Switching Unit (MBSU) that was hampered last week by a possible misalignment and damaged threads where a bolt must be placed. They also installed a camera on the International Space Station?s robotic arm, Canadarm2. The bright sun is visible at left.