The first piece of the space station was Zarya, the Russian control module that was launched into orbit November 20, 1998. A few weeks later, on December 4, 1998, the U.S. module Unity was launched into space. On December 7, 1998, the two modules were connected. This assembly in space was an amazing feat, but it is just the beginning. More than 100 pieces must be connected before the station is complete. The final components are scheduled for 2006—but with all the challenges and dangers ahead, the station may be completed even later than that.
Why does it take so long? Well, consider that the space station assembly will require at least the following:
Forty-six space missions: 37 by U.S. space shuttles, 9 by Russian launch vehicles.
One hundred sixty space walks: It will take astronauts 1,900 man-hours to assemble the station, risking the dangers of the hostile space environment.
One hundred components: over 1 million pounds of hardware.
