International Space Station Gets New Truss Segment

Image: The International Space Station’s new S3/S4 truss and solar arrays are viewed from Space Shuttle Atlantis’ robotic arm. Image credit: NASA TV

The International Space Station grew Monday when STS-117 and Expedition 15 crew members attached the Starboard 3 and 4 truss (S3/S4) segment.

The S3/S4, which is 45 feet long and weighs 35,678 pounds, was attached to the end of the Starboard 1 truss segment by crew members using the station’s robotic arm. The S3/S4 contains a new set of solar arrays that will increase the station’s power-generation capabilities.

The STS-117 crew will conduct three spacewalks to activate the S3/S4. The first spacewalk occurred Monday, and the new solar arrays were deployed Tuesday. The second occurred Wednesday as the spacewalkers assisted with the partial retraction of an older solar array.

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.

Late Sunday, NASA Astronaut Clayton Anderson joined the Expedition 15 crew, replacing Flight Engineer Suni Williams. Anderson arrived at the station as a member of Space Shuttle Atlantis’ crew. Atlantis docked to the station at 3:36 p.m. Sunday.

He and Williams officially changed crews when his custom-made seat liner was swapped out in the Soyuz spacecraft docked to the station. Williams is wrapping up a six-month stay aboard the station