Editing Almaz (section)

===Defense measures===
In addition to reconnaissance equipment, Almaz was equipped with a unique [[Rikhter R-23|23mm Rikhter]] (factory index 261P or 225P) rapid-fire cannon mounted on the forward belly of the station. This revolver cannon was modified from the tail-gun of the [[Tupolev Tu-22]] bomber and was capable of a theoretical rate of fire of 1800-2000 (up to 2600) rounds per minute. Each 168&nbsp;gram (ammo 23-OFZ-D-R ) or 173&nbsp;gram (ammo 23-OFZ-G-R) projectile flew at a speed of 850&nbsp;m/s relative to the station. The cannon was tested at the end of the mission by firing 20 rounds, when the station was operating in uncrewed mode. To aim the cannon, which was on a fixed mounting, the entire station would be turned to face the target.<ref name="ars-2015117">{{Cite news |last=Gallagher |first=Sean |date=November 17, 2015 |title=Russian television reveals another secret: the Soviet space cannon |url=https://arstechnica.com/information-technology/2015/11/russian-television-reveals-another-secret-the-soviet-space-cannon/ |url-status=live |archive-url=https://web.archive.org/web/20230525144255/https://arstechnica.com/information-technology/2015/11/russian-television-reveals-another-secret-the-soviet-space-cannon/ |archive-date=May 25, 2023 |work=[[Ars Technica]] }}</ref> The Almaz series are the only known armed, crewed military spacecraft ever flown.

[[Salyut 3]]/OPS-2 conducted a successful remote test firing with the station uncrewed due to concerns over excessive vibration and noise.

OPS-4 was to have featured two rockets instead of the aircraft cannon, but this system has not been shown publicly and may have never been fully manufactured despite it being used experimentally.{{citation needed|date=April 2021}}