Continuing the postal theme of last week's discussion on the Collectibles and Souvenirs of the National Geographic Society - U. S. Army Air Corps Stratosphere Balloon Flights of 1934 and 1935, this week's topic will cover commemorative envelopes produced specifically for the launch of the Explorer and Explorer II Balloons.
A variety of envelopes (some under the guise of stratosphere mail) was produced with photos or signatures of the balloonists, cachets, and crude drawings for each launch or attempted launch of the Explorer Balloons. Ones produced for the first Explorer II launch attempt in July 1935 had to be hastily stamped with "BALLOON BURST INFLATING 3 A.M. JULY 12, 1935". As shown in the attached photos, all of the commemorative envelopes were postmarked in Rapid City, SD. I am not aware of an official listing of all of the envelopes created for the balloon flights. New examples show up from time to time.
With the absence of a First Day of Issue Stamp, the envelopes created as souvenirs of the flights cannot be accurately described as First Day Covers (FDC). However, to celebrate the 200th Anniversary of Ballooning, on March 31, 1983, the U. S. Postal Service issued a block of balloon stamps which included the Explorer II Balloon. Several FDCs were created to commemorate this celebration. Examples are still readily available and are usually inexpensive to purchase.
Please feel free to share photos of other commemorative envelopes and First Day Covers from the Explorer Balloon flights.
Next week's topic: Passes and Tickets to the Stratobowl.