Maintenance on the station’s mobile transporter and a test of astronaut movement on the end of the robotic arm boom extension for possible heat shield repairs during future flights

Installation of a spare thermal control system pump on to the outside of the Quest Airlock; replacement of reel assembly for a cable that provides power and data to the station’s mobile transporter

Demonstration of on-orbit heat shield repair techniques

Transfer of the Orbiter Boom Sensor System back to the shuttle from its temporary location of the station's truss, or backbone. The crew then prepared the JEM PM for its removal from the shuttle's payload bay. Later that day, the JEM PM was be installed on the port side of Harmony.

Installing covers and external television equipment on the JEM PM and remove covers on the JEM RMS, which will be installed on flight day 8. The spacewalkers also prepared for the flight day 7 relocation of the Japanese logistics module.

Replacing a failed nitrogen tank assembly on the station's truss with a spare that was temporarily stored on one of the station external stowage platforms. They also retrieved a failed camera system on the truss.

Transfer of a failed ammonia pump to the shuttle cargo bay, transfer of the Robotic Refueling Mission (RRM) to the station and place an experiment on ELC-2 for long duration exposure.