USSR
Acknowledged, but not listed by SG.
| Country: | USSR |
| Type: | Postal blocks |
| Series: | Cosmonautics Day, 1987 |
| Nominal: | 8*10 k |
| Year: | 1987 |
| Material: | coated |
| Perforation: | frame 11½ |
| Mintage: | 10,650 |