(06/12/1999) -- At KSC's Shuttle Landing Facility, the 'Super Guppy' transport aircraft touches down on the runway. On board the aircraft is the S0 (S Zero) truss segment, from Boeing in Huntington Beach, Calif. The truss segment, which will become the backbone of the orbiting International Space Station (ISS), is a 44by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch. It will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on-orbit. During processing at KSC, the S0 truss will have installed the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes. Four Global Positioning System antennas are already installed. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108