 The P6 truss was the second truss segment to be added, because it contains a large Solar Array Wing (SAW) that generated essential electricity for the station, prior to activation of the SAW on the P4 truss.It was originally mounted to the Z1 truss and had its SAW extended during STS-97, but the SAW was folded, one half at a time, to make room for the SAWs on the P4 and S4 trusses, during STS-116 and STS-117 respectively.Shuttle mission STS-120 (assembly mission 10A) detached the P6 truss from Z1, remounted it on the P5 truss, redeployed its radiator panels and attempted to redeploy its SAWs.