Kvant-2 (Russian: Квант-2; English: Quantum-II/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.

Kvant-2 also carried the Soviet version of the Manned Maneuvering Unit for the Orlan space suit.

Unlike Kvant-1, Kvant-2's gyrodynes were only accessible from the exterior which made replacement of failed ones more difficult.

Scientific equipment on Kvant-2 included a high-resolution camera, spectrometers, X-ray sensors, the Volna 2 fluid flow experiment, and the Inkubator-2 unit which was used for hatching and raising quail.