STS-118’s second spacewalk is now in the history books. Mission Specialists Dave Williams and Rick Mastracchio successfully installed a new control moment gyroscope (CMG) onto the International Space Station’s Z1 truss during the excursion, which ended at 6 p.m. EDT.
The new CMG replaces a faulty gyroscope, which was removed during the first half of the spacewalk. The new gyroscope is one of four CMGs that are used to control the station’s attitude in orbit.
Before concluding the 6-hour, 28-minute excursion, the orbital duo relocated the faulty CMG to external stowage platform-2, where it will stay until it is returned to Earth on a future shuttle mission.
Mission Specialist Tracy Caldwell served as the spacewalk coordinator, and STS-118 Pilot Charles Hobaugh and Expedition 15 Flight Engineer Clay Anderson operated the station’s robotic arm.
The next spacewalk is scheduled to take place Wednesday. Mastracchio and Anderson will team up to prepare the station’s Port 6 truss for relocation during STS-120. A fourth spacewalk was added to the schedule when STS-118 was extended by three days.
In other activities, crew members continued cargo transfers between Endeavour and the station. Experts on the ground continued to analyze imagery collected Sunday during the STS-118 crew’s focused inspection of five areas of concern on the Endeavour’s heat shield.
Managers Add Three Days to Shuttle Mission
Mission managers decided Sunday to extend the STS-118 mission by three days. The decision came after the successful operation of the new Station-to-Shuttle Power Transfer System (SSPTS).
Endeavour is now scheduled to undock from the International Space Station on Aug. 20 and land Aug. 22. In addition to the extra time at the orbital outpost, managers added a fourth spacewalk that is scheduled to take place Aug. 17.
The SSPTS reroutes power from the space station to the shuttle during docked operations, allowing the orbiter to conserve materials needed to generate power and spend more time in space.