This cover was on board both the “Salyut-7” space station and the “Mir” space station. It is autographed by Russian cosmonauts V.Solovjov and L.Kizim, the crew of the “SoyuzT-15” spacecraft, the last spacecraft of “Soyuz T” series.
13 March 1986 – SoyuzT-15 lift off.
15 March 1986 – SoyuzT-15 docked with the “Mir” station.
05 May 1986 - SoyuzT-15 undocked from the “Mir” station.
06 May 1986 - SoyuzT-15 docked with the “Salyut-7” station.
25 June 1986 - SoyuzT-15 undocked from the “Salyut-7” station.
26 June 1986 - SoyuzT-15 docked with the “Mir” station again.
16 July 1986 - SoyuzT-15 undocked from the “Mir” station and landed.
First the cover was postmarked on Earth about a year before the mission than it was marked on board the both space stations with the pentagonal board souvenir seals. 
