International Space Station

Unity, Nodes 1, 2 and 3

The U.S. Node 2 awaits launch in the Space Station Processing Facility at the Kennedy Space Center (KSC) since its arrival on June 1, 2003.
The U.S. Node 2 awaits launch in the Space Station Processing Facility at the Kennedy Space Center (KSC) since its arrival on June 1, 2003.

Node 1, known as "Unity," a passageway connecting living and work areas of the International Space Station was launched into space on board the Shuttle Endeavour on December 4, 1998.

The 22-foot-long, 18-foot-diameter node joined the U.S.-funded and Russian-built Functional Energy Block (FGB) and the first major U.S-built component of the Space Station. Unity and Zarya FGB were joined in space during three spectacular EVA's by Astronauts Jerry Ross and Jim Newman.

Major installation of hardware in Node 1, the first of three nodes that will be part of the station, was completed in June 1997 at NASA's Marshall Space Flight Center, Ala., by a Boeing/NASA team. Boeing is the U.S. prime contractor for Space Station.

In addition to its connection to the FGB, the node will serve as a passageway to the U.S. laboratory module, U.S. habitation module, or living quarters, and an airlock.

Essential elements such as fluids, as well as the environmental control, life support, electrical and data systems, must be routed through the node because it is a connector to work and living areas. More than 50,000 mechanical items, 216 lines to carry fluids and gases, and 121 internal and external electrical cables using six miles of wire were installed. A Boeing and subcontractor team of 200 supported installation of the equipment and systems.

Hardware installation took place in a clean room, and the node was placed in a rotating tooling fixture that permitted technicians and engineers easier access to all areas. The detailed and complex hardware installation required 1,800 drawings for just a portion of the Boeing work. An aluminum, cylinder-like structure, the node has six hatch or door frames, which serve as docking ports for the other modules.

Pressurized Mating Adapters (PMA), which are cone-shaped, tunnel-like hardware, will be installed on the node at Kennedy Space Center. One PMA will serve as a docking port for the Space Shuttle orbiter and the other as a connecting tunnel from the node to other modules. A PMA supplies the computers that provide command and control of the node. The PMAs are built by Boeing in Huntington Beach, Calif.

Node 2, the "utility hub" and second of three connectors between International Space Station (ISS) modules, was built in the Torino, Italy facility of Alenia Spazio, an International contractor based in Rome. Alenia built Node 2 as part of an agreement between NASA and the European Space Agency (ESA). Weighing in at approximately 30,000 pounds, the Node is more than 20-feet long and 14.5-feet wide. This centerpiece of the ISS will be the next pressurized module installed on the Station and will result in a roomier Station, allowing it to expand from the equivalent space of a 3-bedroom house to a 5-bedroom house once the Japanese and European laboratories are attached to it. The module attaches to the end of the U.S. Lab and provides attach locations for the Japanese laboratory, European laboratory and, later, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS. Node 2 is the designated payload for mission STS-120. No orbiter or launch date has been determined yet. The Marshall Space Center in Huntsville, Alabama manages the Node program for NASA.