Replacing a failed power controller on the station's truss, jettison a refrigerator-sized ammonia reservoir tank and clean seals on a docking port on the Unity module

Preparing for the relocation of the P6 truss segment on the STS-120 mission, moving two equipment carts from the right to left side of the station and relocating an antenna and upgrade avionics and communication systems.

Installing support equipment on the S1 truss that will allow for an addition to the inspection boom during the STS-123 mission, and installing a system to provide better wireless video coverage during future missions

The crew inside removed a new ammonia tank from shuttle's payload bay and temporarily stowed it on the station. Next, the pair installed a grapple bar to the new ammonia tank on the station's truss. The pair also replaced a failed gyroscope that is part of the station's navigation system.

The astronauts removed the empty ammonia tank from the station's truss and temporarily stowed it on an equipment cart. The new tank then was installed and connected to the truss for use.

First they finished the complicated change out of the large ammonia tank assembly. The spacewalkers also removed the grapple bar from the old ammonia tank and stowed it on a spare parts platform.