Hooking up power cables to begin activation of the S3/S4 truss and starting to prepare the Solar Alpha Rotary Joint, also known as the SARJ, for activation

Finishing removing the SARJ's launch locks and restraints so that it can be activated and repairing of the Shuttle's heat shield

Preparing for the replacement of an empty ammonia tank on the station's port truss. They also retrieved a materials processing experiment and a European science experiment mounted outside the Columbus laboratory.

Removing the new ammonia tank from the shuttle's payload bay and replacing it with the used tank on the station.

Preparing for the arrival of the Tranquility node by attaching cables between the starboard truss and the Unity node. The spacewalkers also replaced a communications sensor device, installed two new GPS antennas and a new circuit breaker.