Trusses
Like pieces of an erector set, the trusses will shoulder the four massive solar arrays that will power the station. By the time all nine segments of the main truss structure are in place, this "backbone" of the ISS will be fully 360 feet long.

Trusses Machinists at a Boeing facility in California work on an aluminum bulkhead for the "test article" of the space station's center truss segment.