Almaz The Almaz ( , " Diamond " ) program was a highly secretive Soviet military space station program , began in the early 1960s . Three crewed military reconnaissance stations were launched between 1971 and 1974 : Salyut 2 , Salyut 3 and Salyut 5 . To cover the military nature of the program the three launched Almaz stations were designated as civilian Salyut space stations . Salyut 2 failed shortly after achieving orbit , but Salyut 3 and Salyut 5 both conducted successful manned testing . Following Salyut 5 , the Soviet Ministry of Defence judged in 1978 that the time consumed by station maintenance outweighed the benefits relative to automatic reconnaissance satellite s . The space stations cores were known internally as OPS ( , GRAU index 11F71 and 11F71B ) , from " Orbital Piloted Station " ( ) . As part of the Almaz program several spacecraft for supportive roles were developed : The VA spacecraft , the Functional Cargo Block and the TKS spacecraft , which were to be used in several combinations . The heritage of the Almaz program continues to this day with the ISS module Zarya being one example . Development . Almaz had been promoted by Vladimir Chelomei at the OKB - 52 design bureau as a response to the US Air Force ' s Manned Orbiting Laboratory ( MOL ) project – MOL had been widely published in the early 1960s in the US press , which provided plenty of material for Chelomei to lobby for a Soviet response to this perceived US threat . The Almaz space station programme consisted of three major parts : Much like its counterpart MOL / Gemini , the initial Almaz APOS space station design would call for an Almaz - OPS space station to be launched together with its initial three man crew in a VA return capsule , mated together as OPS / VA atop Chelomei ' s UR - 500 Proton rocket . Once in orbit , and same as MOL / Gemini , the crew would access the lab through a hatch in the heat shield at the bottom of the VA capsule . After an extended stay of 30 to 60 days of military observation and photography the crew would return to Earth by way of a reusable VA return vehicle – the capsule would have been reusable for a total of up to 10 flights . The OPS basic design features are in diameter , a weight of roughly and total pressurized volume . Unlike the American MOL design , the Almaz was designed to be recrewed and resupplied . For this the TKS resupply craft was created , which would be launched with the crew in its VA return craft – the launch vehicle would be again a Proton rocket . At the station , one docking port was available to receive the TKS craft , once the previous crew had left the station with their VA capsule . While the MOL was canceled in 1969 , the Almaz program would be integrated into the Salyut programme and result in three flown space stations , two of which were crewed successfully . As " man - rating " the VA spacecraft and the Proton rocket took longer , the first phase called for the launch of three Almaz stations without the VA spacecraft , with the crew instead launched separately with a Soyuz rocket and a modified Soyuz spacecraft . Plans called for the first three Almaz stations to be visited by 3 two - month - long expeditions each . This was realized fully by two missions and partially with one ; however , the initial intention of launching Almaz APOS and the TKS spacecraft together with its crew in VA spacecraft would never materialize during the program , and neither would the TKS craft play a role as the intended resupply craft . The Almaz APOS design – without VA spacecraft – would evolve into the Almaz OPS station cores of the Salyut programme . Defense measures . 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 had supply of 32 rounds and was tested at the end of the mission , when the station was operating in unmanned mode . To aim the cannon , which was on a fixed mounting , the entire station would be turned to face the threat . Salyut 3 / OPS - 2 conducted a successful remote test firing with the station unmanned 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 . Orbital Piloted Stations ( OPS ) . Three Almaz OPS space stations were flown from 1973 to 1976 in the Salyut programme : Salyut 2 ( OPS - 1 ) , Salyut 3 ( OPS - 2 ) and Salyut 5 ( OPS - 3 ) . Five crewed Soyuz expeditions were flown to the Almaz space stations Salyut 3 and Salyut 5 , with three reaching their stations and only two of the missions being considered fully successful at that time – the three crews that had reached their stations had manned Almaz stations for a total of 81 days when the program was ended . Besides the three flown space stations OPS - 1 to OPS - 3 , seven more spaceframes of Almaz space stations had been build when the program was cancelled : OPS - 4 , Almaz - 205 , Almaz - 206 , Almaz - T , Almaz - T2 ( Kosmos 1870 ) , Almaz - 1 and Almaz - 2 – with Almaz - T2 and Almaz - 1 having successfully flown as repurposed unmanned radar - carrying reconnaissance satellites ( see below ) . The partially outfitted hulls of Almaz - 205 and Almaz - 206 are today in the property of Excalibur Almaz , a company which plans to launch these as manned space stations ( see below ) . Flown Almaz space stations . OPS - 1 ( Salyut 2 ) . The first Almaz station ( OPS - 1 or Almaz 101 . 1 ) , announced as Salyut 2 , it 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 . OPS - 2 ( Salyut 3 ) . 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 unmanned . Salyut - 3 was deorbited in January 1975 . OPS - 3 ( Salyut 5 ) . OPS - 3 ( or Almaz 103 ) , announced after launch as Salyut 5 , entered orbit on June 22 , 1976 . It was visited by two crews in the summer of 1976 and winter of 1977 . Salyut 5 was deorbited on 8 August 1977 , and broke up as it reentered the Earth ' s atmosphere . Unflown Almaz space stations . OPS - 4 . The next Almaz station , OPS - 4 , was to be the first station launched with a three panel Mech - A Synthetic Aperture Radar and a manned 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 manned program was cancelled . Almaz - T ( unmanned ) . Following cancellation of the program , the Almaz station was reconfigured as an unmanned heavy radar - carrying reconnaissance satellite . Three such satellites were launched , two of which functioned successfully in orbit . Almaz - T . 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 . Almaz - T2 ( Kosmos 1870 ) . 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 . Almaz - 1 . 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 - 2 ( Almaz - 1V ) - Not flown . It had a new radar which 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 . Heritage . The heritage of the Almaz space station program continues until today , and can even be found today in the International Space Station . DOS space station cores . 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 . DOS space station cores derived since 1971 from the Almaz - OPS hull design include : Functional Cargo Block ( FGB ) . 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 . 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 still in use on the International Space Station . Excalibur Almaz . 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 . 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 . 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 . Excalibur Almaz has postponed its first launch to 2015 to be able to include more lucrative deep space capabilities like asteroid mining .