The Unity Node is a connecting passageway to living and work areas of the International Space Station. It was the first major U.S.-built component of the station. Unity Node was delivered during
STS-88 on Space Shuttle Endeavour in December 1998. The Pressurized Mating Adapter 1 prefitted to its aft port. The
crews conducted
three space walks to attach Pressurized Mating Adapter 1 to the Zarya Control Module. This was the second International Space Station Assembly Flight and was designated
2A.

In addition to its connection to Zarya, Unity serves as a passageway to the
U.S. Laboratory Module and an airlock. It has six hatches that serve as docking ports for the other modules.
Image to right: This photo of the International Space Station was taken after the undocking of Space Shuttle Endeavour during STS-88.
Physical Description:
5.5 meters (18 feet) long, 4.6 meters (15 feet) in diameter and fabricated of aluminum.
The Unity Node contains more than 50,000 mechanical items, 216 lines to carry fluids and gases, and 121 internal and external electrical cables using 9.7 kilometers (6 miles) of wire.