On May 11, 2013, Marshburn and Expedition 35 flight engineer Christopher Cassidy performed an unplanned spacewalk to replace a pump controller box suspected to be the source of an ammonia coolant leak. Marshburn and his crew returned to Earth on May 13, 2013.
On May 11, 2013, astronauts Marshburn and Cassidy performed an unplanned spacewalk to fix a pump controller box suspected of causing an ammonia leak. They returned to Earth on May 13, 2013.