A NASA unit at the Kennedy Space Center that is the site for the assembly and integration of payloads before their placement into a space shuttle at the Orbiter Processing Facility. Located east of the centre's headquarters building, the five-storey O and C Building has a total area of 55 800 sq m, including a clean room that runs the entire length and height at the rear. Two cranes weighing 24.8 tonnes are used to move the payloads.