Zarya (ISS module) significant event construction
Construction
The Zarya design was originally intended as a module for the Russian Mir space station, but was not flown as of the end of the Mir program.  A FGB cargo block was incorporated as an upper stage engine into the Polyus spacecraft, flown (unsuccessfully) on the first Energia launch.  With the end of the Mir program, the design was adapted to use for the International Space Station.
The Zarya module is capable of station keeping and provides sizable battery power; it was suggested to have initially been built to both power and control the recoil from a further derivation of the then classified Skif laser system/Polyus satellite. Commentators in the West thought that the Zarya module was constructed cheaper and lifted to orbit faster than should have been possible in the post-Soviet era, and that the FGB might have been largely constructed from mothballed hardware from the Skif laser program (which had been canceled after the failed 1987 Polyus launch).The research and development of a similar design was paid for by Russia and the Soviet Union, the design of the module and all systems are Soviet/Russian. The United States funded Zarya through the U.S. prime contracts in the 1990s as the first module for ISS. Built from December 1994 to January 1998 in Russia at the Khrunichev State Research and Production Space Center (KhSC) in Moscow.  The module was included as part of NASA's plan for the International Space Station (ISS) instead of Lockheed Martin's "Bus-1" option because it was significantly cheaper (US$220 million vs. $450 million). As part of the contract, Khrunichev constructed much of an identical module (referred to as "FGB-2") for contingency purposes. FGB-2 was proposed to be used for a variety of projects; it has been used to construct the Russian Multipurpose Laboratory Module Nauka.