Commanded by Pavel Belyayev and piloted by Alexei Leonov, Voskhod 2 was launched into orbit on March 18, 1965. Alexei Leonov became the first man to walk in space at 08:34.51 UTC — 90 minutes into the mission. This first, tentative spacewalk was reportedly plagued with problems. For example, due to over-pressurization of his spacesuit and a bad boarding procedure, Leonov briefly became stuck in the airlock and had difficulty re-entering the Voskhod 2 spacecraft.
These stamps appear to depict the crew of the 1964 Voskhod 1 space flight: Vladimir Komarov, Konstantin Feoktistov, and Boris Yegorov. This was the first multi-person space flight.
Notice the strong left-to-right diagonal composition in both of these stamps. In cultures which parse lines of text from left to right, a line angled such that the left is lower than the right is interpreted as rising and emotionally uplifting.
This compositional approach is useful when an artist or designer wishes to intimate a positive future.
When reversed — such that the left is higher than the right — this is useful to intimate a positive past.
(Take a look at the last few posts regarding these vintage CCCP stamps — you may notice this compositional approach repeated quite a lot.)