STS-92 was an ISS assembly flight that brought the
Z1 truss, Control Moment Gyros,
Pressurized Mating Adapter-3 (PMA-3) (mounted on a
Spacelab pallet) and two DDCU (
Heat pipes) to the
space station. The
Z1 truss was the first
exterior framework installed on the ISS and allowed the first U.S. solar arrays to be temporarily installed on
Unity for early power during flight 4A. The Ku-band communication system supported early science capabilities and U.S. television on flight 6A. The CMGs (Control Moment Gyros) weigh about and provide non-propulsive (electrically powered) attitude control when activated on flight 5A, and PMA-3 provides shuttle docking port for solar array installation on flight 4A and
Destiny Lab installation on flight 5A. The mission included seven days of docked operations with the
space station, four
EVAs, and two ingress opportunities. Over the course of four scheduled
spacewalks, two teams of
space walkers and an experienced
robot arm operator collaborated to install the
Z1 (Z for zenith port) truss structure on top of the
U.S. Unity connecting node on the growing station and to deliver the third Pressurized Mating Adapter (PMA 3) to the
ISS for the future berthing of new station components and to accommodate shuttle dockings. The
Z1 truss was the first permanent lattice-work structure for the ISS, very much like a girder, setting the stage for the future addition of the station's major
trusses or backbones. The Z1 fixture also served as the platform on which the huge U.S.
solar arrays were mounted on the next shuttle assembly flight,
STS-97. The Z1 truss included many elements of the
Communications and Tracking subsystem. The
hardware included a
Transmitter/Receiver/Controller (SGTRC) built by L3 Communications Systems-East in
Camden, NJ. John Schina was the Chief Engineer of the
ISS Program at L3. The Z1 contains four large
gyroscopic devices, called
Control Moment Gyroscope (CMGs), which are used to maneuver the
space station into the proper orientation on
orbit once they were activated following the installation of the
U.S. laboratory. During the fourth
spacewalk, astronauts
Wisoff and
López-Alegría tested the
SAFER jet backpack, flying up to 50
feet while remaining
tethered to the
spacecraft. ==Media==