NASA Flight Engineer Sunita Williams and Japan Aerospace Exploration Agency Flight Engineer Akihiko Hoshide completed the second spacewalk of the Expedition 32 mission at 4:33 p.m. EDT Thursday. They began the spacewalk at 8:16 a.m.

During the spacewalk, Williams and Hoshide were unable to install a new Main Bus Switching Unit (MBSU) on the International Space Station's s-zero truss. After removing and stowing the failed unit, the spacewalkers had difficulties driving the bolts to secure the replacement switching unit in the s-zero truss.

Williams and Hoshide used a long-duration tie-down tether to secure the replacement MBSU to the space station for a future spacewalk.

Prior to this task, Williams was able to successfully connect one of two power cables in preparation for the future arrival of a Russian laboratory module. The third objective, replacing a camera on the Canadarm2 robotic arm, was not completed.

Today's spacewalk was the fifth for Williams and the first for Hoshide. Hoshide is the third Japanese astronaut in history to conduct a spacewalk. The spacewalk was the 164rd in support of station assembly and maintenance and was the first U.S.-based spacewalk since July 2011.

The first Expedition 32 spacewalk was performed by Commander Gennady Padalka and Flight Engineer Yuri Malenchenko on Aug. 20. The primary task during their 5-hour, 51-minute excursion was the move of the Strela-2 cargo boom from the Pirs docking compartment to the Zarya module. Other tasks included the installation of micrometeoroid debris shields on the exterior of the Zvezda service module and the deployment of a small science satellite.