Looking back at 25 years of the ISS The US-built Unity node docked with the Russian-built Zarya module on December 6, 1998.

This unique orientation of the Northrop Grumman Cygnus space freighter attached to the Unity module is pictured from the Russian segment of the International Space Station. At lower center, in ...

All-female spacewalking team carry out battery work at Interntional Space Station Jim Newman works outside of the Unity module of the International Space Station.

Once Tranquility was structurally mated to Unity, the spacewalkers connected heater and data cables that will integrate the new module with the rest of the station’s systems.

The International Space Station was born on December 6, 1998, when the U.S. Unity module was deployed from space shuttle Endeavour and mated with Russia’s Zarya module.