KSC-07-S-00038

After a smooth countdown, Space Shuttle Atlantis begins the STS-117 mission with a spectacular climb toward orbit. Atlantis is delivering a new segment to the starboard side of the International Space Station's backbone, known as the truss. Three spacewalks are planned to install the S3_S4 truss segment, deploy a set of solar arrays and prepare them for operation. STS-117 is the 118th space shuttle flight, the 21st flight to the station, the 28th flight for Atlantis and the first of four flights planned for 2007.