The P4 is the second port truss segment that will attach to the first port truss segment P1 truss.

The P4 truss arrives via truck from Tulsa, Okla. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.