D-6
Two versions of the D-6 launch system for solid-fuel missiles were researched by OKB-7 (KB Arsenal) in Leningrad between 1958 and 1960. One used a missile with a single large diameter motor using propellants that were already in production for use in unguided tactical rockets. The second version focused on a new missile incorporating new solid propellants using a crystal oxidizer and fuel, with the first and second stages consisting of clusters of four separate rocket motors. The overall dimensions of either missile would have been too large for a launching tube inside the pressure hull, so the D-6 launcher design called for two tubes on each side of the outside of the hull. To fire the missiles the submarine would surface and the tubes would be turned into a vertical position. The preliminary design of the launch system was completed in 1960. The beginning of detailed design development of the D-6 complex was directed on 18 June 1960, but in June 1961 the program was cancelled.
