Zvezda is around 1⁄ 4 the size of Polyus, and has no armaments. The Mir-2 space station was redesigned after the failure of the Polyus orbital weapons platform core module to reach orbit. The space frame was completed in February 1985 and major internal equipment was installed by October 1986. Its design lineage thus extends back to the original Salyut stations. It was in fact labeled as Mir-2 for quite some time in the factory. This means that Zvezda is similar in layout to the core module (DOS-7) of the Mir space station. The basic structural frame of Zvezda, known as 'DOS-8', was initially built in the mid-1980s to be the core of the Mir-2 space station.
