Mid-shot of Seller on EVA3 during STS-121 / Expedition 13 joint operations

S121-E-06583 (12 July 2006) --- Astronaut Piers J. Sellers, STS-121 mission specialist, participates in the mission's third and final session of extravehicular activity (EVA). The demonstration of orbiter heat shield repair techniques was the objective of the 7-hour, 11-minute excursion outside Space Shuttle Discovery and the International Space Station.