The payload canister left with the Integrated Truss Structure Z1 nears the top of the passage to the Payload Changeout Room.

With its umbilical hoses stretched out, the payload canister (left) with the Integrated Truss Structure Z1 inside nears the top of the passage to the Payload Changeout Room. There the Z1 truss will be removed and later transferred to Space Shuttle Discovery’s payload bay. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT