Mission Control Center, Houston, Texas

HOUSTON – Mission Specialists Scott Parazynski and Doug Wheelock today will work to repair a torn solar array on the farthest end of the International Space Station's port truss in the fourth spacewalk of the STS-120 mission.

That spacewalk is slated to begin about 5:30 a.m., but could begin as early as 5 a.m. if the crew's final preparations move quickly as they have for the rest of the mission's spacewalks.

The crews of Space Shuttle Discovery and the station were awakened this morning at 12:38 with composer John Williams' theme song from the original "Star Wars" movie trilogy. The song was played for Parazynski.

Parazynski and Wheelock spent the evening in the Quest airlock at a lower air pressure to get ready for the 6.5-hour spacewalk. Yesterday, the two reviewed the detailed plans for the spacewalk with flight controllers and engineers who have been working around the clock to prepare the plan.

The day will begin with a hand-off of the Orbiter Boom Sensor System (OBSS) from the shuttle's robotic arm to the station arm. The OBSS is an extension to the shuttle arm used for inspection of the orbiter's thermal protection system. This will be the first time the OBSS will be used to reach a worksite, which was simulated on STS-121 in July 2006.

Parazynski will take a 45-minute ride on the mated OBSS to the damaged area of the array, estimated to be about 90 feet up from the P6 truss, to repair the tear in the 4B panel of the array. One of his first tasks will be to test the dynamics of the work platform to better understand how it will move as he moves. Once he arrives at the worksite, Parazynski will install homemade stabilizers and release the snag suspected of causing the tear in the array panel. Wheelock will assist from the base of the solar array.

If all goes as planned, the crew inside will then deploy the array half a bay at a time while Parazynski watches for any new complications. The spacewalk is scheduled to wrap up about Noon.

The astronauts should then be able to spend Sunday preparing to leave the station with Discovery's undocking scheduled early Monday morning. Landing is set for just after Noon on Wednesday.

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

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