Harmony Module Delivery Doubles Station Volume to Five-Bedroom Scale

The International Space Station doubled its living capacity on October 23, 2007, when the shuttle Discovery delivered the Harmony module.

The delivery, designated mission STS-120, transformed the orbiting complex from a structure the size of a three-bedroom house into one comparable to a five-bedroom home. This expansion provided the physical infrastructure necessary for sustained human presence in orbit.

Harmony measures 24 feet long and 14 feet wide, a footprint similar to a minibus. Built by Italy-based Thales Alenia Space, the module was the second NASA-led hub constructed for the station. It features five common berthing mechanisms that serve as standardized connection points for other spacecraft and laboratory sections.

The module functions as a central utility hub. It houses the sleeping quarters for American astronauts and contains eight payload racks. Four of these racks are dedicated to avionics, while the remaining four provide stowage or crew living space. The name was selected through a public contest run by NASA.

Prior to this delivery, the station had not received a new primary module since 2001. That year, Russia attached the Pirs docking module, which has since been discarded. Harmony’s arrival initiated a new phase of growth by providing the necessary connections for international laboratories.

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 at the Destiny module. This maneuver cleared space for Harmony to be permanently berthed at the forward port of Destiny.

From its permanent position, Harmony links the European Space Agency's Columbus module on the starboard side and Japan's Kibo laboratory on the port side. The module also includes a docking port on its roof for visiting vehicles and has hosted cargo ships at its external ports.