STS-92 PAYLOADS
International Space Station Assembly Flight 3A

Space Shuttle Discovery and its seven-member crew will set the stage for future International Space Station assembly missions during STS-92 by delivering Pressurized Mating Adapter 3, or PMA 3, and an exterior framework structure, the Z1 Truss, to the station. The STS-92 astronauts will conduct four space walks and use Discovery's robot arm to install the Z1 Truss and connect PMA 3 to the space station's Unity Connecting Module.

Z1 Truss
The Z1 Truss will be the first permanent latticework structure for the space station, very much like a girder, setting the stage for the future addition of the station's major trusses or backbones. The Z1 fixture will also serve as the platform on which the huge U.S. solar arrays will be mounted on the next shuttle assembly flight, STS-97. It includes power distribution components, four flat discs that will be used to control the station's attitude, communications equipment, temperature control system hardware, space walk/extravehicular aids and power, data and coolant connections.

Pressurized Mating Adapter 3
PMA 3 will provide a place for an orbiter to dock with the U.S. segment of the International Space Station. PMA 3 includes latches and hooks to be used in docking, space walk aids, heaters and temperature control equipment, electrical power subsystem, and data cables that can be hooked up to a docked spacecraft. PMA 3 will not be used for docking until assembly flight 4A.