Mir-2 was a space station project which began in February 1976. Some of the modules built for Mir-2 have been incorporated into the International Space Station (ISS). The project underwent many changes, but was always based on the DOS-8 base block space station core module, built as a back-up to the DOS-7 base block used in the Mir station. The DOS-8 base block was eventually used as the Zvezda module of the ISS. Its design lineage extends back to the original Salyut stations.
The prototype of the central module was as Polyus. Mir-2 would be capable of docking at least four modules in ordinary operation.
Designated as OSETS (Orbital Assembly and Operations Centre). The station would be built in a 65 degree orbit and consist of 90 ton modules.Launch 1 - DOS 8, providing housing for the assembly crew.
Launch 2 - 90 ton module.
Launch 3 - Truss and solar arrays.
Launches 4 to 6 - additional 90 ton modules.
This would involve launch of the DOS-8, after which the Buran shuttle would grapple the module, rendezvous with Mir, and attach it to the old DOS-7 base block. This plan was later altered so that DOS-8 would maneuver and dock itself to Mir. It would remain attached for two years.
The station would consist of the DOS-8 core module and a cross beam called the NEP (Science Power Platform). This was equipped with MSB retractable solar panels, Sfora thruster packages and small scientific packages.
Four 3 to 4 ton modules were planned:Docking Module - with the APDS universal androgynous docking system, and a side hatch for space walks
Resource Module - Equipped with gyrodynes for orienting the station and a passive docking port for docking of Soyuz or Progress ferry spacecraft
Technology Module - with materials experiments
Russian elements of the International Space Station include:Zarya FGB, the first element launched. This was a US-funded TKS-derived propulsion module built by KB Salyut.
Zvezda Service Module - this is the DOS-8 station, which was launched as the third major ISS module in July 2000.
SO-1 (Pirs) - one of the docking modules originally designed for Buran/Mir-2 was added to the station in September 2001.
SO-2 Poisk - A module similar to Pirs. Poisk also provides extra space for scientific experiments, and power-supply outlets and data-transmission interfaces for external scientific payloads.
Rassvet -the only module delivered by NASA shuttle, in a barter exchange for the launch 'owed' for Zarya. Rassvet is used for cargo storage, science, and as a docking port for visiting spacecraft.