Astronauts Rick Linnehan (right) and Robert L. Behnken, both STS-123 mission specialists, participate in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station.

During the 6-hour, 53-minute spacewalk, Linnehan and Behnken installed a spare-parts platform and tool-handling assembly for Dextre, also known as the Special Purpose Dextrous Manipulator (SPDM).

Among other tasks, they also checked out and calibrated Dextre's end effector and attached critical spare parts to an external stowage platform. The new robotic system is scheduled to be activated on a power and data grapple fixture located on the Destiny laboratory on flight day nine.

Photo by NASA