The crew of Atlantis is prearing for first spacewalk after a successful docking with the International Space Station. They will use the station’s robotic arm and conduct a spacewalk to attach and activate a new truss segment.

Jim Reilly and John "Danny" Olivas will leave the space station's confines at 1853 GMT for more than six hours to begin installing a new set of solar panels delivered by the seven-member Atlantis shuttle.

Reilly and Olivas will use the spacewalk to open and connect a set of solar panels that make up the truss segment, one of 11 that will form part of an integrated structure to permanently power the station.

NASA officials meanwhile said they were still weighing their options after a portion of a thermal blanket peeled back during Atlantis' launch on Friday.

Later in the day, STS-117 spacewalkers Jim Reilly and John “Danny” Olivas will go to work outside of the space station to begin activation of the S3/S4. The spacewalk, which is the first of three scheduled for STS-117, will start at 2:53 p.m. and last 6.5 hours.

The current projects are intended to boost the space station's electricity supply in preparation for installation in December of the European module Columbus. That will lay the foundation for the later delivery of the Japanese research module Kibo.

The new solar panels are to double power at the station by 2010, when construction on the space station is to be finished. Final occupancy is to be expanded to from three full-time astronauts to six residents.

Flight Director John Shannon said it would have little effect on the shuttle's re-entry, but that they were nevertheless considering simply pushing it back into place during one of the upcoming space walks.