It is the first scientific module included in OS. SPC Energy developed it. Module Kvant was launched on March 31, 1987 by LV Proton-K from the launching pad Baikonur. At the launch the module consisted of two docked units: module Kvant itself and transportation and energy module (after docking with the OS was separated and sank in the Pacific Ocean). Mass of the module at the launch was 20000 kg; total length was 13 m, fuel mass 5000 kg. Power supply was provided by the storage batteries. Mass of the module in the OS is 10600 kg, useful load mass is 4100 kg and hermetic volume is 40 m3. Module Kvant is docked to the stern axial docking port of the core vehicle and has a docking port to dock to the transportation ships. The original mix of the scientific equipment was aimed at the astrophysics investigations. At present truss construction with the moving setting up the navigation system are installed on the module and SB' panels from the module Crystal are transferred on it. The composition of the scientific equipment of the module is in the table.