The mated Russian-built Zarya (left) and U.S.-built Unity modules are backdropped against the blackness of space and Earth’s horizon shortly after leaving Endeavour’s cargo bay on Dec. 13, 1998. A few days earlier, on Dec. 6, 1998, the space shuttle Endeavour, mission STS-88, launched from NASA’s Kennedy Space Center in Florida carrying the Unity connecting module and two pressurized mating adapters. The same day, the STS-88 crew captured the Russian Zarya module, launched Nov. 20, and mated it with the Unity node. Unity was the first piece of the International Space Station provided by the Un…