The Soviet Union planned several military Soyuz spacecraft models. These versions were named Soyuz P, Soyuz PPK, Soyuz R, Soyuz 7K-VI, and Soyuz OIS (Orbital Research Station). However, none ever flew in space.
The Soyuz P (Perekhvatchik, Interceptor) space interceptor and Soyuz R (Razvedki, intelligence) command-reconnaissance spacecraft was proposed in December 1962 by Sergei Korolev. In the initial draft project, the Soyuz P would use the Soyuz 9K rocket stage and Soyuz 11K tanker spacecraft to conduct a series of dockings and re-fueling operations. The complete complex would then conduct intercepts of enemy satellites in orbits up to 6,000 km in altitude.
The Soyuz-R system consisted of two separately launched spacecraft, including the small orbital station 11F71 with photo-reconnaissance and electronic intelligence equipment and a Soyuz 7K-TK for crew transport.
Initially the Soyuz P was designed for piloted inspection and destruction of enemy satellites. It was intended that the Soyuz would rendezvous with the target satellite. To minimize risk to the crew, a new version, Soyuz PPK (pilotiruemovo korablya-perekhvatchika, crewed interceptor spacecraft) was later proposed.
The Zvezda (star) station was based on a radically modified Soyuz. Objectives were human 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 cancelled 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 Nikolaevich 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.
The Soyuz OIS (Orbital Research Station) would consist of a separately-launched orbital block 11F731 OB-VI and a transport Soyuz 7K-S.
The Soyuz OB-VI would be launched for 30-day missions in a 51.6° orbit at 250 x 270 km. Power was provided by solar panels, and the payload included 700 to 1,000 kg of instrumentation. The total mass would be around 6,500 kg (14,300 lb).
The initial Soyuz 7K-S program was to consist of four uncrewed, followed by two crewed test flights, then two operational launches. Cosmonauts were assigned to the project in 1973.
In 1975, the project was cancelled. At that time the launch escape system for 7K-S was ready and was used for Apollo-Soyuz Test Project flights. Three complete vehicles were launched as uncrewed test missions: