The S1 (Starboard One) truss and the joint airlock (Quest) are shown in a clean room at the Boeing facility in Huntsville, Ala. Space shuttle Atlantis delivered the airlock in July 2001. Space shuttle Atlantis will deliver S1 during mission STS-112. S1 attaches to the right of the S0 (Starboard Zero) truss already aboard the space station. The P1 (Port One) truss is a mirror image of S1 and will be carried aloft by space shuttle Endeavour on mission STS-113. P1 attaches to the left side of the S0 truss. The space station's truss structure will eventually span more than 300 feet and carry power, data and environmental services throughout the orbital outpost. Boeing is NASA's prime contractor for the International Space Station and responsible for design, construction, integration and operation of the station.