Seeds of a Space Station
Construction of the International Space Station in orbit was a monumental achievement that lasted more than a decade and involved thousands of engineers, mission planners and astronauts. But it started with a single moment—the joining of the U.S. Unity module (right) and the Russian Zarya module on December 6, 1998, during mission STS-88. By the time the station was completed in 2011, the orbiting lab would weigh a million pounds and stretch the length of a football field.