Soyuz 7K-VI Zvezda
The Zvezda (star) station was based on a radically modified Soyuz. Objectives were manned earth observation, orbital inspection and destruction of enemy satellites. Zvezda would be powered by two plutonium radioisotope generators and had a recoilless gun for defense. It was designed for shooting in a vacuum and defending the military research spacecraft from enemy satellite inspector and interceptor satellites. The gun was aimed by maneuvering the entire spacecraft. A special gunsight was installed in the descent module for aiming the gun. A forward docking apparatus to allow docking with Almaz was also included. Work on Zvezda was canceled in 1967 with a single prototype in advanced stages of construction.
Cosmonaut training for the VI began in September 1966. The cosmonaut group selected included commander Pavel Popovich, pilot Alexei Gubarev, flight-engineers Yuri Artyukhin, Vladimir Gulyaev, Boris Belousov, and Gennadiy Kolesnikov. Popovich-Kolesnikov and Gubarev-Belousov were the prime crews, with the other engineers acting as reserves and then assigned to later crews.
Read more about this topic: Military Soyuz