Unity (Node 1) is a connecting passageway to living and work areas of the International Space Station. It is the first major U.S.-built component of the station, joining Zarya (FGB). Unity will be delivered by the space shuttle with Pressurized Mating Adapter 1 prefitted to its aft port. The STS-88 shuttle crew conducted three spacewalks to attach PMA 1 to Zarya. 
    In addition to its connection to Zarya, the node serves as a passageway to the U.S. laboratory module, U.S. habitation module and an airlock. It has six hatches that serve as docking ports for the other modules. 


Node 2 is a U.S. element that provides internal storage and pressurized access between modules. It consists of six docking ports - four radial and two axial. Three of the radial ports are used for the attachment the Columbus Orbital Facility (COF), the Centrifuge Accommodations Module (CAM), and the Japanese Experiment Module (JEM). The remaining radial port is used for attaching the Multi-Purpose Logistics Module as necessary during Shuttle missions.


The U.S. Laboratory provides equipment for research and technology development. It also houses all the necessary systems to support a laboratory environment and control the US Segment. 
    This module has a capacity of 24 rack locations. Payload racks will occupy 13 locations especially designed to support experiments. These racks will be transported to the ISS by the shuttle as cargo integrated into the Mini-Pessurized Logistics Module (MPLM) and transferred to the U.S. Laboratory during joint shuttle/station operations.



The Japanese Experiment Module (JEM), [called "Kibo" which means "Hope" in English] is a Japanese element that provides laboratory facilities for Japanese material processing and life science research. It also contains an external platform, airlock, and robotic manipulator for in-space (“exposed”) experiments and a separate logistics module to transport JEM experiments. (see image above)


The Columbus Orbital Facility (COF) is provided by the European Space Agency (ESA) as its part in the International Space Station Program. It is designed as a general purpose laboratory which can support any foreseen user discipline, including materials and fluid sciences, life sciences and technology development. 


The Habitation Module is a U.S. element that provides six-person habitation facilities, such as personal hygiene (better waste management, full body shower), crew health care, and galley facilities (wardroom with eating facilities, oven, drink dispenser, freezer/refrigerator).


The Cupola is a U.S. element that provides direct viewing for robotic operations and shuttle payload bay viewing.