ISS Astronauts Complete 4th Spacewalk

June 18, 2007

Mission Specialists Patrick Forrester and Steven Swanson check the Drive Lock Assembly 2 on the S3/S4 truss segment of the International Space Station. Image credit: NASA TV

STS-117’s final spacewalk came to an end Sunday at 6:54 p.m. EDT. During the 6-hour, 29-minute orbital stroll, Mission Specialists Patrick Forrester and Steven Swanson performed tasks to activate the International Space Station’s new truss segment and completed work that will help future spacewalkers.

Forrester and Swanson began the excursion at 12:25 p.m. and quickly went to work preparing the Starboard 3 and 4 (S3/S4) truss segment for operation. The S3/S4 was installed onto the station on June 11. Most of the S3/S4 work centered on activating the Solar Alpha Rotary Joint (SARJ), which will allow the S3/S4 arrays to track the Sun.

Early in the spacewalk, Forrester verified the installation of the Drive Lock Assembly 2, one of two mechanisms that will drive rotation of the SARJ, while Swanson installed a TV camera and its support structure. Then, the duo removed the final launch restraints on the SARJ before removing a keel pin and drag link to clear the path for the station’s mobile transporter.

The get-ahead tasks included the installation of a computer network cable onto the Unity module and the removal of a Global Positioning System antenna. The two astronauts also finished the installation of a piece of debris shielding on the Destiny laboratory.

Mission Specialist Jim Reilly coordinated the spacewalk and Pilot Lee Archambault operated the robot arm. Forrester and Swanson conducted STS-117’s second spacewalk. Reilly and Mission Specialist Danny Olivas conducted the other two. Sunday’s spacewalk is the 87th devoted to station assembly and maintenance.

Attention now turns to Atlantis' departure and the events leading up to undocking. The STS-117 crew is scheduled to exit the station Monday before the hatches close at 6:23 p.m. EDT. Atlantis is slated to undock at 10:42 a.m. Tuesday.

However, mission managers may decide to add a day of docked operations for STS-117 if the Russian navigation computers do not perform adequately during a test of Russian attitude control capabilities Monday morning at 10:28 a.m.

Credit: NASA