STS-92 Mission Specialist Leroy Chiao signals thumbs up for launch, scheduled for 8:05 p.m. EDT. The mission is the fifth flight for the construction of the ISS. The payload includes the Integrated Truss Structure Z-1 and the third Pressurized Mating Adapter. During the 11-day mission, four extravehicular activities (EVAs), or spacewalks, are planned. The Z-1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. PMA-3 will provide a Shuttle docking port for solar array installation on the sixth ISS flight and Lab installation on the seventh ISS flight. This launch is the third for Chiao. Landing is expected Oct. 21 at 3:55 p.m. EDT