I recently bought the book "Project Mercury" by Eugen Reichl, translated from German into English. I'm puzzled by a photo on page 11, purporting to be of "The very first launch of the Atlas ... June 11, 1957." It definitely seems to be an "A" model, but on the side are painted two confusing numbers which could be interpreted in various reversed or inverted ways - "51" or maybe "15." I don't have launch photos of the "A's" which show such numbers... Can any of you sleuths help? By the way the Atlas photos on pages 83 and 103 are definitely printed reversed left-to-right, obvious from the side lettering. Sloppy!
I may not have understood your post correctly.When I click on the image, the number that I see on the vehicle is 12 not 15.That makes me suspect that this is 12A.
I have the launch of 12A as the 3rd Atlas A on 1957/12/17 at 1738 UTC and it is described as a successful limited range test where the engines fired for 2 minutes.
But I've seen other references that say the 1957/12/17 flight was 07A.
Atlas missile launch (Febr. 20, 1958).Original image caption: Cape Canaveral - February 20, 1958 -- The launch of a U.S. Air Force Atlas missile, test number 449, takes place from the Air Force Missile Test Center. (U.S. Air Force photo)
It isn't 10A, since it can't be the back side a. The turbopump exhaust goes out the back sideb. The pad ramp in is the foreground and hence it is the front side of the vehicle.