- $4.99 7.15.1975 Sagamore Hill Radio Observatory - South Hamilton, MA - F73623
- $4.99 1972 Prognos-1 - Measure Radio Waves - F7777
- $4.99 1968 Radio Astronomy Explorer 38 - Milky Way Radio Mapper - F7232
- $4.99 1970 Australia - Solar Radio Observatory Culgoora - F11840
- $2.50 GERMAN U.S. AEROS-2 RADIO COMMUNICATIONS SATELLITE LAUNCH 7/16/1974 VANDENBERG
- $5.00 1964 Radio Astronomy Explorer 20 Satellite
- $5.00 1964 Radio Astronomy Explorer 20 Satellite a
- $5.00 1964 Radio Astronomy Explorer 26 Satellite
- $3.49 11.16.1973 Northeast Radio Observatory Corp - Westford, MA - F61192
- $4.99 1973 Russia - PROGNOS 1 - Measure Radio Waves & Solar Radiation - F4703
- $4.99 1970 Australia - Mills Cross Radio Telescope - F11841
- $15.00 VINTAGE SPACE COVER -USA-USSR DISCUSS CARPENTERS RADIO FADE OUT IN DENMARK 1962
- $4.99 1973 Germany - Radio Telescope - Effelsberg - F5845
- $4.99 1971 EXPLORER 43 - Eletronic Field & Radio Astronomy Exp - F2689
- $4.99 Apr 11 1970 - Apollo 13, Sagamore Hill Radio Observatory - Wenham, MA - F35868
- $4.99 1974 AEROS 2 - US-German Satellite - Radio Communications - F6099
- $4.99 38.9.9 Japan - 14th Gen Assembly of the Int'l Scientific Radio Union - F20467
- $4.99 1973 Germany - Skylab - 100m Radio Telescope - Effelsberg - F5844
- $4.99 1973 - National Radio Astronomy Observatory - F5589
- $4.99 1973 - National Radio Astronomy Observatory - F5589
- $4.99 1970 India - XIIth Plenary Assembly - Int'l Radio Consultative Commitee - F5197
- $4.99 1973 Northeast Radio Observatory Corp - F5607
- $4.99 36.9.9 Japan - 14th Gen Assembly Int'l Scientific Radio Union - F20512
- $3.00 AOP2 Australia Apollo 15 Fleurs Radio Observatory cover