 The International Space Station's main source of energy is from three of the four large U.S.-made photovoltaic arrays currently on the station, sometimes referred to as the "Solar Array Wings" (SAW).The first pair of arrays are attached to the P6 truss segment, which was launched and installed on top of Z1 in late 2000 during STS-97.The P6 segment was relocated to its final position, bolted to the P5 truss segment, in November 2007 during STS-120.