FDC made in the Soviet Union, 1968. The envelope is about space orbits.
The envelope is about Zond 5. Zond 5 was a spacecraft of the Soviet Zond program. In September 1968 it became the second spaceship to travel to and circle the Moon, and the first to return safely to Earth.
Zond 5 carried the first terrestrial organisms to the vicinity of the Moon, including two tortoises, fruit fly eggs, and plants. The tortoises underwent biological changes during the flight, but it was concluded that the changes were primarily due to starvation and that they were little affected by space travel.