Salyut 1 was launched 20-April-1971. It was unsuccessfully attempted to be boarded by the crew of Soyuz 10 and successfully hosted the ill-fated Soyuz 11.

This first day cover was cancelled for the launch of the space station.

Salyut 2 was launched 4-April-1973. All such space stations were launched using the larger Proton rocket launch vehicles whilst all other launches from Sputnik, through Vostok, Voskhod, Soyuz and later Progress use the same R-7 rocket launch vehicle. A problem after detachment of the launch vehicle meant that the station became unstable, lost its solar panels and thus power and depressurised. It was never used and was de-orbited 28-May-1973.

This first day cover was issued on the launch of the space station and is cancelled in Moscow on that day.

And this is a second cover was issued on the launch of the Salyut 2 space station, and is also cancelled on the day.
The next Salyut space station was the first successful space station. It was launched 24-June-1974 and successfully hosted just one crew whilst in orbit (Soyuz 15 failed to dock). Salyut 3 was dubbed the military Salyut as it housed a gun designed to be fired upon other space objects. The recoil from firing such a weapon would have destabilised the orbiter and so was only tested when de-orbited on 24-January-1975.

This first day cover was issued on the 26-June-1974 and is typical of the Salyut first day covers.

This attractive first day cover was issued for launch day 24-June-1974.
This first day cover is typical of the many issued for events during space station missions (crew launch, docking, undocking and return to Earth). This case it is of Salyut 3's only successful docking and was achieved Soyuz 14 (Popovich of Vostok 4's flight) on the 4-July-1974. It also features an attractive 1972 Salyut Soyuz stamp.
Unlike Salyut's 2 and 3, Salyut 4 was not of military design and was akin to Salyut 1. Salyut 4 had two crews (Soyuz 17 and 18) and was manned at the same time as the joint Apollo Soyuz mission occurred. Salyut 4 was launched on 27-December-1974 and finally de-orbited on 2-February-1977.

This first day cover was issued for the launch of the Salyut 4 space station and features a stylised Soviet space propaganda stamp "Four stars to Mars" depicting the Mars probes 4,5,6 and 7 of 1973-74.

Pictured here is a Space Voyager cover issued for Soyuz 17's 10-January-1975 launch. Soyuz 17 was the first crew to visit the Salyut 4 space station and on docking the crew found a humorous note from the ground crew asking them to "Wipe your feet" when entering.
Salyut 5 was of the same military design as the Salyut 2 and 3 was hosted two crews. It was launched 22-June-1976 and de-orbited 8-August-1977.
In an attempt to increase the duration that the space station crews remained in orbit, unmanned resupply craft were developed. Salyut 6 was the first space station to deploy duel docking stations allowing a manned Soyuz craft to be attached whilst an unmanned Progress craft also docked. Salyut 6 was launched 29-September-1977 and Progress 1 was launched 29-January-1978. Salyut 6 hosted 16 crews, five of them long term and was de-orbited 29-July-1982 after four and a half years.

A rare find is this Salyut 6 launch cover cancelled on the 29-September-1977.

Top is a card showing an artists impression of the Salyut 6 space station featuring its double ending docking and hosting both a manned Soyuz and an unmanned Progress resupply craft.

Bottom is a 1978 Leonov designed card featuring Salyut 6 with both a Soyuz and Progress unmanned resupply craft.

This first day cover is an attractive example of a cover commemorating the launch of the Progress 6 resupply craft to the Salyut 6 space station and a 1977 Cosmonautics day stamp is cancelled 15-May-1979.
This is another attractive example of such a first day cover this time with a 1978 intercosmos Soyuz stamp. This cover was issued for the launch of Progress 7 on 28-June-1979 and carried the KRT-10 astronomical radio telescope. The resupply craft by this calculation must carry about 6 weeks worth of supplies to the space station.
This is a 1980 Cosmonautics day cover commemorating the Progress 7 delivery to Salyut 6 of the KRT-10 radio telescope and the space walk performed to install it.
Salyut 7 was the backup vehicle for Salyut 6 and was launched on 19-April-1982 due to delays in the Mir stations readiness. It remained in orbit for over eight years before being de-orbited 7-February-1991, most of that time crewed.

This cover was cancelled for the launch.

Here we have a maxicard cancelled in 1987 featuring an artists impression of Salyut 7, a Soyuz and a Progress craft linking up.
Learning from the Salyut experience the Mir space station was devised with many more docking modules allowing it to be expanded in stages and to host multiple vehicles. Vehicles ferried supplies from Salyut 7 during the opening stages of Mir.

This first day cover is a typical example of a cover commemorating the launch of any Progress or Soyuz missions, but it is for the launch of the Mir space station 20-February-1986 and is cancelled at Baikonur Cosmodrome. The stamp is of the 1985 Soyuz T12 crew.

Here is a postcard of the Mir space station.
This is a maxicard also for the launch of the Mir space station and features a 1982 Cosmonautics day stamp.
The Buran was the Soviet Space shuttle that was launched using the Energia heavy launch rockets. The Energia rocket had its maiden launch on 15 May 1987. The Buran's maiden unmanned flight 15-November-1988, but never flew again due to the collapse of the Soviet Union. The Buran was lost due to a fire in its hanger.

This cover commemorates its first and only flight, being cancelled for the launch and features its own miniature sheet.

This example of numbered Buran cover was one of the batch loaded on board the Buran for its maiden flight. The covers were removed before take off and so are often referred to as the "Almost flown Buran covers".
Here are further examples of numbered Buran cover.
And this is a third example of a numbered Buran cover.
Here is a selection of postcards from Bulgaria and the Soviet Union featuring the Buran and Energia.
STS-71 - Atlantis first shuttle/Mir docking
- 4-July-1995
This Russian first day cover has been autographed by the crew of the Mir space station. It also features the complete set of four stamps issued for the event and is cancelled at Moscow for the docking 29-June-1995 with the official first day postmark. Hand signed by the crew members who were waiting on board MIR: Anatoly Solovyev, Nikolai Budarin, Vladimir Dezhurov, Gennady Strekalov.

The crew of Orbital Station MIR after docking: Gibson, Precourt, Harbaugh, Baker, Dunbar, Solovyev, Budarin, Thagard, Dezhurov, Strekalov.

Progress M-34 Mir docking - 25-June-1997
The Mir space station survived a docking maneuver collision with the Progress M-34 resupply vehicle in 1997 resulting in the de-pressurisation of a module. This Russian cover depicts this event.
Progress M-35 Mir docking - 7-July-1997
Although not of historical significance, here is another example of the attractive first in covers issued by Russia for their space flights. This one is for the resupply vehicle Progress M-35 that successfully docked with Mir after the collision 1997.
STS-76 - Atlantis Mir docking - 24-March-1996
Here is the Russian first day cover cancelled 27-March-1996 commemorating the joint shuttle / Mir mission.
This is a second Russian cover commemorating the undocking. It features two of the four stamps issued for the First Atlantis Mir docking STS-71 and is cancelled 29-March-1996.
STS-91 - Final Mir docking - 2-June-1998
This is a Colorano Silks cover issued for the final docking of Mir by the space shuttle. This was the last visit by America's shuttle fleet to Mir the first being STS-71 followed by STS-74, STS-76, STS-79, STS-81, STS-84, STS-86, STS-89 and finally STS-91.
MIR - Deorbited
The Mir space station remained manned constantly from 1989 until 1999. After one last crew in 2000 it was decided to de-orbit the station in March 2001 over the Pacific. The lessons learned from Mir lent much to the International Space Station.

This is an American Colorano silks cover issued for the deorbiting.