S118-E-07997 (15 Aug. 2007) --- Astronauts Rick Mastracchio (right), STS-118 mission specialist; and Clay Anderson, Expedition 15 flight engineer, participate in the mission's third planned session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the 5-hour, 28-minute spacewalk, Mastracchio and Anderson relocated the S-Band Antenna Sub-Assembly from Port 6 (P6) to Port 1 (P1) truss, installed a new transponder on P1 and retrieved the P6 transponder. The blackness of space and Earth's horizon provide the backdrop for the scene.