Pasadena California is the location of the the Jet Propulsion Laboratory which is the control center for the spacecraft listed above. A full description of the cover is given so you know exactly what you are ordering. There were 6 FMF printed cachets used for these FDC's, they were all issued previously for other space FDC's and space events,but are appropriate for these space exploration stamps. 3 of these 6 FMF printed cachets commemorate the Voyager Spacecrafts and were issued 10 years prior to this first day of issue, for the launch of the Voyager Spacecrafts. All covers are the number 6 size, the standard for U.S. collectors.
All covers are unaddressed.
Cover also has affixed a special black and orange imperf. The local stamp commemorates the closest approach to Saturn by Voyager 2 in August 1981.