It was the last in an unprecedented series of three U. S. spacewalks in nine days from the Quest airlock. Major tasks of this spacewalk included removing and jettisoning two large shrouds and installing an attachment for cargo carriers.
Lopez-Alegria and Williams moved from the airlock out to Crew Equipment Transfer Aid (CETA) carts on the rails of the main truss. Pushing one cart with their equipment, including a foot restraint, they moved to the Port 3 truss segment. Their first job was to remove two thermal shrouds, one from each of two Rotary Joint Motor Controllers (RJMC) on P3.
Next, they removed two large shrouds from P3 Bays 18 and 20. The shrouds, larger than king-size bed sheets, provide thermal shading. With the station in its present orientation, they are no longer needed and are being removed to avoid trapping heat.
Each large shroud was packed with one of the smaller RJMC shrouds into a package weighing about 20 pounds. Lopez-Alegria jettisoned them toward the rear of the station. Afterward, an Unpressurized Cargo Carrier Assembly Attachment System (UCCAS) on the upper face of the P3 truss was deployed. That was done in preparation for attachment of a cargo platform on the STS-118 mission to the ISS later this year.
While Lopez-Alegria finished work on the UCCAS, Williams moved to the end of the P5 truss to remove two launch locks in preparation for the relocation of the P6 truss to that segment.
The final scheduled task of the spacewalk was connecting the final four cables of the Station to Shuttle Power Transfer System (SSPTS) to Pressurized Mating Adapter-2 (PMA-2) at the forward end of the Destiny laboratory where shuttles dock. The SSPTS will allow visiting shuttles to derive power from the station to extend their missions.
Work began on the system during the Jan. 31 spacewalk, and two of the cables were routed and connected to PMA-2 on the Feb. 4 spacewalk. The astronauts completed one get-ahead task to photograph a suspect connector on the outboard end of PMA-2. It carries station shuttle communications when the shuttle is docked but hatches are closed. Communications have been intermittent during recent shuttle missions.
Approximately 3 hours, 50 minutes into his ninth spacewalk, Lopez-Alegria set a record Thursday for cumulative spacewalk time by a U.S. astronaut. Jerry Ross previously held the title with 58 hours, 32 minutes accumulated during nine spacewalks. Lopez-Alegria completed the spacewalk with 61 hours, 22 minutes of spacewalking time.
The three spacewalks from the Quest airlock in U.S. spacesuits and a Russian spacewalk on Feb. 22 are the most ever done by station crew members during such a short period and will mark five spacewalks in all for Exp. 14, a record for any expedition. Starting from scratch, it takes crew members about 100 hours to prepare for a spacewalk. By doing the U.S. spacewalks just a few days apart, considerable crew time can be saved by not having to repeat some of the preparation.
Thursday's spacewalk was the 80th for station assembly and maintenance. It was the 52nd from the station and the 32nd from Quest. It was the fourth for Williams, the most for any woman.
During the final spacewalk on Feb. 22, Lopez-Alegria and Flight Engineer Mikhail Tyurin will wear Russian Orlan suits to work on an antenna on the Progress 23 cargo ship docked at the aft port of the Zvezda service module. The antenna did not properly retract when that spacecraft docked in October. The spacewalkers will try to secure or remove the antenna to avoid any interference with the undocking of a Progress in April. The spacewalk will be the 10th for Lopez-Alegria, a new record for a U. S. astronaut.