Space Station Growth: 2007 Harmony Delivery Reshapes Interior Layout

The International Space Station reached a new size threshold on October 23, 2007, when shuttle Discovery delivered the Harmony module.

The delivery, part of the STS-120 mission, expanded the orbiting complex from the footprint of a three-bedroom house to that of a five-bedroom house. This physical increase allowed the station to support longer crew rotations and more complex research operations by providing dedicated space for American astronauts. The module measures 14 feet wide and 24 feet long, a size comparable to a standard minibus.

Harmony functions as a critical utility hub that connects major international components. It links the European Space Agency's Columbus module and the Japanese Kibo laboratory to the rest of the station. The module contains five common berthing mechanisms that serve as connection points for other segments. These ports have also accommodated visiting cargo ships, while a roof port allows additional vehicles to dock.

The installation process required careful reconfiguration of the station's structure. Astronauts initially attached Harmony to the Unity node while the shuttle remained docked. After Discovery departed, the crew used the station's robotic arm to move the shuttle docking port away from the Destiny laboratory. This maneuver cleared the forward port of Destiny for Harmony's permanent placement.

Before this flight, the station had not received a new main module since Russia's Pirs docking unit arrived in 2001. Pirs has since been discarded. Harmony, originally designated Node 2, followed Unity, or Node 1, as the second hub built under NASA leadership. The module was manufactured by Italy-based Thales Alenia Space. Inside, the module holds eight payload racks. Four are allocated for avionics, while the remaining four serve as stowage or crew quarters. The name was selected through a public contest organized by NASA.