Almaz

In addition to reconnaissance equipment, Almaz was equipped with a unique 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 Tu-22 bomber and was capable of a theoretical rate of fire of 1800-2000 (up to 2600) rounds per minute. Each 168 gram (ammo 23-OFZ-D-R ) or 173 gram (ammo 23-OFZ-G-R) projectile flew at a speed of 850 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.[7] 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.

The first Almaz station (OPS-1 or Almaz 101.1) was launched on April 3, 1973. For purposes of military secrecy, it was publicly designated Salyut 2 upon reaching orbit. A crew was prepared to fly to the station but an accident days after the launch left OPS-1 disabled and depressurized.[10]

OPS-2 (or Almaz 101.2), announced as Salyut 3, was launched on June 25, 1974. The crew of the Soyuz 14 spacecraft spent 15 days aboard the station in July 1974. A second expedition was launched toward OPS-2 in August 1974, but failed to reach the station. The station successfully remotely test-fired an onboard aircraft cannon at a target satellite while the station was uncrewed. Salyut-3 was deorbited in January 1975.[8]

OPS-3 (or Almaz 103), announced after launch as Salyut 5, entered orbit on June 22, 1976. It was visited by two crews in mid-1976 and late 1977. Salyut 5 was deorbited on 8 August 1977, and broke up as it reentered the Earth's atmosphere.[11]

The next Almaz station, OPS-4, was to be the first station launched with a three panel Mech-A synthetic-aperture radar and a crewed reusable Return Vehicle VA, however the VA was replaced by a second TKS docking port. This station's Shchit-1 23 mm defense cannon was also to be replaced with an advanced Shchit-2 space-to-space cannon. The Shchit-2 was reported to be a two projectile system, although no photographs of it have ever been published and it does not appear that this system was ever installed on the station. OPS-4 was grounded when the Almaz crewed program was cancelled.

Almaz-T – The first Almaz-T blasted off from Baikonur on October 29, 1986. It did not reach orbit due to the failure of the first and second stages of the Proton launcher to separate. The safety system then destroyed the vehicle.

Kosmos 1870 – On July 25, 1987, Almaz-T2, the second Almaz-T spacecraft, successfully reached orbit with an inclination 71.92 degrees toward the Equator and it was officially identified as Kosmos-1870. The spacecraft functioned for two years, providing radar imagery with a resolution down to 25 meters, until it was deorbited on July 30, 1989.

It was the first commercial radar satellite, according to Art Dula (chairman of Excalibur Almaz), who worked in a company marketing the radar images gathered by the satellite.[13]

Almaz-1 – The third Almaz-T spacecraft was launched on March 31, 1991, under the name Almaz-1. After the launch a failure of the communications antenna designed to downlink the imagery via the Luch relay satellite was noted. Also one of the solar panels failed to deploy completely, leaving the main radar panel of the spacecraft partially blocked. After 18 months of successful work the Almaz-1 was deorbited on October 17, 1992, over the Pacific Ocean.

Almaz-2 (Almaz-1V) – Not flown. It had a new radar that would have provided a resolution of 5 to 7 meters. In addition, an optical-electronic payload on the station would have been capable of producing imagery with a resolution of 2.5 – 4 meters.

The DOS space station core modules were based on the Almaz-OPS hull design, which was mated by Sergei Korolev's organization OKB-1 with their own Soyuz-derived subsystems. OKB-1 was at that time in competition with the designer of the Almaz, Vladimir Chelomei's organization OKB-52, and was thereby able to short-cut the development time for the first space station and beat OKB-52, which had started design work much earlier.[14]

DOS space station cores derived since 1971 from the Almaz-OPS hull design include:

• DOS-1, which formed the basis for Salyut 1 space station, in 1971 the first space station in the history of space flight
• DOS-5 and DOS-6, the cores for the long lived Salyut 6 and Salyut 7 space stations
• DOS-7, the Mir Core Module for the Mir space station, the first modular space station
• DOS-8, the Zvezda "Service Module" for the International Space Station, as of 2020 still in use

The modules based on the DOS design are not the only heritage of the Almaz program still in use: The habitat, propulsion and service module of the TKS spacecraft, the so-called Functional Cargo Block (FGB), went on to become the core of many Soviet and Russian space station modules.[2] The FGB-based Kvant-1 module of the Mir space station was the first space station module of its kind, and the Zarya Functional Cargo Block, which is as of 2018 still in use on the International Space Station.

The private spaceflight company Excalibur Almaz has bought the two partially completed Almaz-205 and Almaz-206 space station hulls from the Russian NPO Mashinostroyeniya (the former OKB-52) with the stated intention to outfit and launch them.[15][16][17][18][19] The Almaz-205 module is similar to the OPS-2 of the Salyut 3 station, while the Almaz-206 is closer to the OPS-3 of the Salyut 5 station.[20]

In addition, Excalibur Almaz acquired four VA return capsule hulls (derived from the TKS/VA spacecraft) and plans to outfit and launch them as well: one is planned to be used in support of space tourism while the other three capsules are reserved for scientific and commercial payloads. The needed development of propulsion systems for the VA capsule was reportedly delegated to an unnamed European organization as early as 2009.[17]

Excalibur Almaz as of January 2012 postponed its first launch to 2015 to be able to include more lucrative deep space capabilities like asteroid mining.[21] However, in 2015 the company was reported to be in problems, and it was not clear what happened to their spacecraft. [22]