Node 3 module under construction at Thales Alenia Space in Turin, Italy. Once in space, Node 3 will connect to the port side of the Unity Node and will provide room for eight refrigerator-sized racks, two of the locations being used for the avionics racks controlling Node 3. It will house many of the Station's Environmental Control and Life Support Systems (ECLSS), including an air revitalisation system, an oxygen generator system, a water recycling facility, a waste and hygiene compartment and a treadmill for crew exercise, which are currently stored in various places around the Station.

The Node 3 connecting module is the last element of a barter agreement by which ESA supplied NASA with Space Station hardware including the Cupola and two Node modules (Node 2 and 3). In return, NASA ferried the European Columbus laboratory to the ISS in February 2008.