Suspended from an overhead crane in the Space Station Processing Facility, the P3 Integrated Truss Structure glides along the ceiling to a workstand, at right. The port-side P3 truss is scheduled to be added to the International Space Station on mission STS-115 in 2002 aboard Space Shuttle Atlantis. . The P3 will be attached to the first port truss segment, P1, being installed in an earlier mission