Module "Z1 ITS"

Launch & orbit data:

Z1 truss (above) and Unity Module (below) from STS-92 in October 2000.

Description:

• The first truss piece, the Z1 truss, launched aboard STS-92 in October 2000 is being used as a temporary mounting position for the P6 truss and solar array, attached on the subsequent shuttle flight, STS-97. Though not a part of the main truss, 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. It contains the control moment gyroscope (CMG) assemblies, electrical wiring, communications equipment, and two plasma contactors designed to neutralize the static electrical charge of the space station. It is unpressurized, but features two Common Berthing Mechanism docking ports for easy connecting and data communications. One port is used to connect the Z1 truss to the zenith port of Unity. The other port was used to temporarily store PMA-3. In October 2007, the P6 was moved to its permanent position next to P5, and the Z1 truss is now not used for connecting other elements, but solely to house the CMGs, communications equipment and the plasma contactors.

• Z1 was built by Boeing/Canoga Park and is 3.5 x 4.5 meters in size.
• On Oct 14, 2000 at 1615 UTC the Z1 segment was unberthed from the payload bay and at around 1820 UTC it was docked to the +Z zenith port on the Unity module. On Oct 15 at 1420 UTC the ODS airlock was depressurized, beginning a spacewalk by Bill McArthur and Leroy Chiao. The hatch was probably unsealed at around 1425 UTC. The spacesuits went to battery power at 1427 UTC, and the thermal cover on the airlock was opened at 1430 UTC. McArthur exited the airlock about 1446 UTC. The astronauts connected cables between Z1 and Unity, relocated the SASA S-band antenna on Z1, and deployed Z1's SGANT Ku-band antenna. They then took the port ETSD (EVA stowage) box from the Spacelab pallet and installed it on Z1. The astronauts were back in the airlock around 2040 UTC and closed the hatch at about 2050 UTC. Repressurization began at 2055 UTC for a depress duration of about 6h 35min, a hatch open/close duration of 6h 25 min, and a NASA (battery power to repress) duration of 6h 28 min.