USSR
Acknowledged, but not listed by SG.
| Country: | USSR |
| Type: | Postal blocks |
| Series: | Cosmonautics Day, 1986 |
| Nominal: | 10*15 k |
| Year: | 1986 |
| Material: | coated |
| Perforation: | comb 12 x 12½ |
| Mintage: | 350,000 |
