Mission Control Center, Houston, Texas

HOUSTON ' Astronauts Scott Parazynski and Doug Wheelock today install the International Space Station's P6 truss in its final location. A new task was also added to this third spacewalk of the mission to provide comparison data of the station's two solar array rotary joints. The spacewalk is set to begin at 3:53 a.m. CDT.

Today's wakeup music at 11:38 p.m., 'Malaguena Salerosa' by Chingon, was played for Pilot George Zamka, who will be operating the shuttle robotic arm.

After analyzing photos of debris found inside the station's starboard Solar Alpha Rotary Joint, mission managers decided Parazynski should take time near the end of the spacewalk to inspect the port rotary joint to provide a comparison. The joints rotate the solar arrays to track the sun for electrical power generation. Parazynski will take photographs and samples of any debris he finds for evaluation.

On Monday managers also decided to devote the mission's fourth spacewalk on Thursday to additional inspection of the starboard joint. That joint has been experiencing increased friction during rotation for the past month and a half and station operators have limited its use while the situation is assessed.

The fourth spacewalk originally was to test a shuttle tile repair dispensing 'gun' known as the T-RAD. That test has been deferred to a future shuttle mission.

During today's spacewalk, Parazynski and Wheelock will work at the end of the port truss to help station robotic arm operators attach the P6 to its new location on P5. The two will provide verbal cues to Expedition 16 Flight Engineer Dan Tani and Mission Specialist Stephanie Wilson as they align the truss.

Once the 17.5 ton truss is in place, Wheelock will secure it with the mechanical capture claw so the two can install the bolts that will permanently hold it and then attach its power source.

Next, the spacewalkers will remove thermal shrouds on P6 and configure the P6 radiator for deployment by ground controllers. Wheelock will also install a spare main bus switching unit on a station storage platform. Zamka and Wilson will operate the shuttle robotic arm during this hardware transfer task.

Following the spacewalk the giant solar array wings on P6 will be redeployed so they can begin gathering sunlight for power again.

The next STS-120 status report will be issued Tuesday afternoon or earlier if events warrant.

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