A suffix letter may be added to some LIST ID numbers to differentiate between different events, cancels, etc.
All covers are unaddressed unless otherwise noted.
All covers are cacheted and a brief description is given of the event being commemorated. If covers are autographed they are genuine. Will participate in GARP world weather program. Small Astronomy Satellite C, to monitor x-ray sources both within and beyond our galaxy. Each satellite can carry 3500 two-way telephone conversations or 12 TV channels and other communications traffic.