Meanwhile, managers approved a repair task for a damaged thermal blanket to be carried out during the next spacewalk Friday.
During the second spacewalk of Space Shuttle Atlantis’ mission, Forrester and Swanson today removed all of the launch locks holding the 10-foot-wide solar alpha rotary joint in place. The spacewalkers had planned to remove the joint’s launch restraints as well, but left them for a later spacewalk.
The spacewalkers ran into a problem when Forrester tried to install a drive-lock assembly and found that commands being sent to it were actually being received by a drive-lock assembly installed during the mission’s first spacewalk. Flight controllers confirmed that the drive-lock assembly installed earlier was in a safe configuration and are working to confirm that the newly installed assembly is as well.
Once fully activated, the drive-lock assemblies engage gears permitting the massive joint to rotate allowing the arrays to track the sun as the station circles the Earth.
To enable it to do so, spacewalkers also had to help retract an older solar array to clear the new array’s path. The process is delicate, as the panels of the solar arrays tend to get caught on their guide wires and fold in the wrong direction. Flight controllers started the retraction before the crew woke up, and were able to get seven and a half of the 31.5 solar array bays folded. Then, on the spacewalk, Forrester and Swanson were able to poke and prod another five and a half bays worth of panels into folding correctly before moving on to other tasks.
The astronauts also were able to make sure the arrays were in a good configuration for another try by flight controllers on Thursday. If necessary, the spacewalkers could provide more hands-on help during one of the mission’s remaining two spacewalks.
Meanwhile, as the second spacewalk continued, mission managers decided that at least part of the third spacewalk, scheduled for Friday, will be dedicated to repairing a raised corner of a thermal insulation blanket that came loose from the shuttle during launch. Mission Specialist Danny Olivas will staple the corner to an adjacent blanket and use pins to secure it to a thermal protection tile.
Russian flight controllers will be working overnight to resolve a problem with the Russian segment computers that provide backup attitude control and orbital altitude adjustments. For now, the station’s control moment gyroscopes are handling attitude control, with the shuttle’s propulsion providing backup.