Shuttle Discovery Delivered a Module That Doubled Station Space in 2007

The International Space Station effectively doubled its living space on October 23, 2007, when the space shuttle Discovery delivered the Harmony module. This 24-foot utility hub, roughly the length of a minibus, transformed the orbiting complex from a structure comparable to a three-bedroom house into one resembling a five-bedroom home. The delivery was the centerpiece of the STS-120 mission, a roughly two-week flight that marked a major shift in the station's physical footprint.

Harmony serves as a central connection point for the station's international components. It links the European Space Agency's Columbus module with Japan's Kibo laboratory. The module also contains the sleeping quarters for American astronauts. Before this addition, the station had not received a new room since 2001, when Russia's Pirs docking module was attached. That earlier module has since been removed from the station.

The installation process required precise maneuvering. Upon arrival, astronauts temporarily attached Harmony to the Unity node. After the shuttle departed, the crew used the station's robotic arm to move the shuttle docking port away from the Destiny laboratory. This action cleared the forward port of Destiny, allowing Harmony to be secured in its permanent position. From this location, Harmony became the primary link for future module attachments.

Harmony was the second hub module built by NASA, following Unity. It was originally designated as Node 2. The Italian company Thales Alenia Space constructed the module for the U.S. government. The structure features five common berthing mechanisms that allow other sections to connect. These ports have hosted visiting cargo ships, while a port on the roof accommodates other visiting vehicles.

Internally, the module holds eight payload racks. Four of these racks contain avionics equipment. The remaining four are used for storage or crew quarters. The name Harmony was selected through a public contest organized by NASA. The module's 14-foot width and 24-foot length provide the necessary structural support for the station's expanded configuration.

The arrival of Harmony initiated a new phase of growth for the station. By providing a dedicated hub for international labs, it enabled the permanent integration of Columbus and Kibo. The module remains a core component of the station's layout, facilitating the movement of crew and cargo between different sections of the outpost.