On Nov. 20, 1998, the first piece of the International Space Station launched into orbit.
The 42,000-pound module is called Zarya, and it’s about the size of a tour bus. Zarya launched on board a Russian Proton rocket. Two weeks later, the STS-88 shuttle mission brought the Unity module into space.
The STS-88 astronauts connected the two modules in orbit. Zarya was built by the Russians, but it was paid for by the United States. NASA contracted a Russian company to build it for half the price of what the American company Lockheed Martin would have charged.
These days, Zarya is mainly used for storage and for external fuel tanks. The module also has docking ports for Russian Progress cargo ships and Soyuz spacecraft that carry crews to and from the space station.
Today, the International Space Station is about the size of a football field and typically hosts up to six crewmembers. But back then, it was a pretty tight squeeze.