Mission Specialists Robert L. Behnken and Mike Foreman completed the fifth spacewalk of STS-123 at 10:36 p.m. EDT. Rick Linnehan, also a mission specialist, coordinated their activities from inside the orbiting complex made up of space shuttle Endeavour and the International Space Station.

Robot arm operators grappled the Orbiter Boom Sensor System (OBSS), and the two spacewalkers assembled an umbilical designed to keep the boom safe during its time in the harsh space environment. Then, the robot arm handed the OBSS off to Behnken and Foreman, who stowed it on the station's S1 Truss.