Kvant-2

Kvant-2 (; English: Quantum-2) (77KSD, TsM-D, 11F77D) was the third module and second major addition to the Mir space station. Its primary purpose was to deliver new science experiments, better life support systems, and an airlock to Mir. It was launched on November 26, 1989 on a Proton rocket. It docked to Mir on December 6. Its control system was designed by the NPO "Electropribor" (Kharkiv, Ukraine).

==Description== thumb|200px|Isolated view of Kvant-2 thumb|200px|Cut-away view of Kvant-2 Kvant-2 was the first Mir module based on the TKS spacecraft (77K module). Kvant-2 was divided into three compartments. They were the EVA airlock, the instrument/cargo compartment, and the instrument/experiment compartment. The instrument/cargo compartment could be sealed off and act as an extension or a back-up to the airlock. Before Kvant-2 docked to the station, EVAs had to be carried by depressurizing the docking node on the Core Module. Kvant-2 also carried the Soviet version of the Manned Maneuvering Unit for the Orlan space suit. It delivered the Salyut 5B computer which was an improvement over the Argon 16B computer already on the station. Kvant-2 had a system for regenerating water from urine and a shower for personal hygiene. It carried six gyrodynes to augment those already located in Kvant-1. Unlike Kvant-1, Kvant-2's gyrodynes were only accessible from the exterior which made replacement of failed ones more difficult.