(9) United States First Day Covers (FDCs) featuring milestones in
space exploration, NASA missions, communications satellites, planetary exploration, Skylab, Apollo-Soyuz, Mariner, and Pioneer spacecraft. Issued between
1960 and 1975, these collectible covers include official First Day cancellations and attractive cachets, with many produced by
Fleetwood.
| Issue | Scott Number(s) |
|---|
| Echo I Communications Satellite (4¢) | Scott 1193 |
| Decade of Space Achievements (8¢) | Scott 1434 |
| Apollo-Soyuz Test Project (10¢ pair) | Scott 1564a |
| Skylab (10¢) | Scott 1529 |
| Mariner 10 Venus/Mercury (10¢) | Scott 1557 |
| Pioneer Jupiter (10¢) | Scott 1558 |