The International Space Station (ISS) began its assembly with the launch of the Russian control module Zarya on November 20, 1998. This was followed by the launch of the U.S.-built Unity connecting node in December 1998. These initial components were linked in orbit by U.S. space shuttle astronauts, marking the beginning of the ISS’s construction in space. The ISS has been continuously occupied since November 2, 2000, when its first resident crew arrived. The station is a collaborative effort involving the United States, Russia, Canada, Japan, and 11 European Space Agency members.