A new Mellone first day cover cachet for my IGY collection

I may be forgotten, but not quite gone.

In a previous post, I mentioned that the specialized Mellone catalogs of cachets on first day covers listed a number of known cachets for U.S. IGY first day covers. The Mellone catalog listed 31 such covers for the U.S. IGY stamp. For a long time, years I think, I have had 25 of these. I recently acquired my 26th (coincidentally also cover #26 in the Mellone listings)! But the majority of IGY covers in my collection were not listed by Mellone. I was pretty excited to find this cover on eBay, and the price was quite favorable.

US242 in my IGY cover collection; Mellone #26 for stamp Scott 1107

Note that in the sidebar of this blog, showing a historic event that happened on or about this day during the IGY (www.eventshistory.com/), I listed that on today's date, 21 August, the Soviet Union in 1957 successfully conducted a long-range test flight of the R-7 Semyorka, the first intercontinental ballistic missile. According to Wikipedia, a modified version of that missile carried Sputnik 1 into orbit on 4 October 1957 and Sputnik 2 on 3 November 1957.