Mission Control Center, Houston, Texas

For the fourth time in less than a week, the astronauts on Space Shuttle Atlantis are about to venture outside their spacecraft to press ahead with assembly of the International Space Station.

The crew's wakeup call came at 6:38 a.m. CDT with the theme song from "Band of Brothers," played for Mission Specialist Jim Reilly.

Spacewalkers Patrick Forrester and Steven Swanson begin their second EVA of the flight at 11:33 a.m., with Reilly choreographing the excursion from the shuttle flight deck. Flight Engineer Oleg Kotov will shadow Reilly as intravehicular crewmember, training to take that role for an upcoming station spacewalk.

The first task is to retrieve a TV camera stand from a stowage platform attached to Quest and install it on the S3 truss. From there the spacewalkers will move to the intersection of the S3 and S4 trusses to prepare the Solar Alpha Rotary Joint for rotation. Forrester will verify the installation of a second Drive Lock Assembly, the machine that turns the S4 truss so its solar array wings can track the sun. He will then help Swanson remove the last six SARJ launch restraints to free the joint to turn.

To clear the path on S3 for the Mobile Base System, Forrester and Swanson will remove temporary rail stops and the hardware that secured the S3/S4 in the shuttle payload bay. Then, they will translate back to the body of the station for a few get-ahead tasks.

As time permits, the spacewalkers plan to install a computer network cable on the Unity node, remove a Global Positioning System antenna, tighten the gimbal locks on the S-band Antenna Support Assembly, open the hydrogen vent valve on the Destiny laboratory that was installed on Friday's spacewalk, and secure the orbital debris shield panel. Today's spacewalk is scheduled to conclude at 6:03 p.m.

The Russian central computer and terminal computers continue in stable operation, each running on two of its three channels with the third in standby. Mission Control in Moscow has restarted all Russian systems except the Elektron, which is receiving power but not moded to generate oxygen, and is planning to fire Russian attitude control thrusters in conjunction with a maneuver of the mated stack to a water dump attitude on Monday.

The next STS-117 status report will be issued Sunday evening after the spacewalk, or earlier if events warrant.

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