Orbital Expansion: Harmony Module Arrival Doubled Station Volume in 2007
The 2007 delivery of the 24-foot utility hub connected European and Japanese laboratories, transforming the station from a three-bedroom to a five-bedroom footprint.
By Natalia Costa ·
The International Space Station faced a structural limitation for years, unable to expand its living and working space without a central connection point. That bottleneck was resolved on October 23, 2007, when the space shuttle Discovery launched the Harmony module into orbit. This single delivery tripled the station's internal volume, shifting its scale from the equivalent of a three-bedroom house to that of a five-bedroom house.
Harmony, originally designated as Node 2, was built by the Italian firm Thales Alenia Space for NASA. The module measures 14 feet wide and 24 feet long, a size comparable to a minibus. It serves as the primary utility hub for the station's international partners. Specifically, it provides the necessary physical link for the European Space Agency's Columbus module and Japan's Kibo laboratory. Before this installation, the station had not received a new room since 2001, when the Russian Pirs docking module was attached.
The installation process required careful coordination between the shuttle crew and the station crew. Upon arrival, the astronauts temporarily attached Harmony to the Unity node. After the shuttle departed, the remaining crew utilized the station's robotic arm to reposition the shuttle docking port on the Destiny module. This maneuver cleared the path for Harmony to be moved to its permanent berthing location beside Destiny.
Harmony contains five common berthing mechanisms that act as connection points for other modules. Four of its eight payload racks are dedicated to avionics. The remaining four racks are used for stowage or crew quarters. NASA's astronaut sleeping facilities are located within this module. A docking port on the module's roof also allows visiting vehicles to park there.
The module's name was selected through a public contest run by NASA. It followed Unity, or Node 1, which was the first NASA-led hub module. The addition of Harmony marked the start of a new phase of station growth by providing the infrastructure needed for future international laboratories.
The STS-120 mission lasted approximately two weeks. Following the shuttle's departure, the crew completed the relocation of Harmony from its temporary position at Unity to the forward port of the Destiny laboratory. This final placement established the permanent link for the starboard-side Columbus lab and the port-side Kibo lab.
