S128-E-007171 (1 Sept. 2009) --- Astronaut John Olivas, STS-128 mission specialist, participates in the mission's first session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 35-minute spacewalk, Olivas and astronaut Nicole Stott (out of frame), mission specialist, removed an empty ammonia tank from the station's truss and temporarily stowed it on the station's robotic arm. Olivas and Stott also retrieved the European Technology Exposure Facility (EuTEF) and Materials International Space Station Experiment (MISSE) from the Columbus laboratory module and installed them on Discovery's payload bay for return. The blackness of space and Earth's atmosphere provide the backdrop for the scene.