The payload canister is ready to be opened in the Payload Changeout Room at the pad. Inside is the S1 Integrated Truss Structure, primary payload on mission STS-112 aboard Space Shuttle Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during the mission. Atlantis is scheduled to launch no earlier than Oct. 2.