On the morning of October 14, 1962, a U-2 aircraft, piloted by Air Force Major Richard D. Heyser, flew a reconnaissance mission over the western part of Cuba, flying from south to north. The 928 photographs obtained during the 6-minute flight over the island produced the first verified evidence of the existence of Soviet offensive missile sites in Cuba. Analysis and interpretation of the photographs at the National Photographic Intelligence Center revealed that three medium-range ballistic missile sites were being developed near San Cristobal, in Pinar del Rio province. Photo analysts counted eight large MRBM transporters at the three locations and four erector launchers in tentative firing positions. Two further U-2 missions, flown on October 15 by pilots of the Strategic Air Command, revealed a fourth MRBM site near San Cristobal, and two intermediate-range ballistic missile (IRBM) sites were discovered at Guanajay. Photos also revealed 21 crates for Soviet IL-28 Beagle medium-range bomber aircraft at San Julian airfield. (Chronology of Air Force Actions During the Cuban Crisis, 14 October-30 October 1962; USAF Historical Division Liaison Office, pages 11-12)
At 8:30 p.m. on October 15 CIA Deputy Director Carter reported to McGeorge Bundy the hard evidence of the MRBM's, but the President's Special Assistant decided not to notify the President that evening. In a memorandum to the President, dated March 4, 1963, Bundy explained his reasons for this decision:
"1. This was very big news, and its validity would need to be demonstrated clearly to you and others before action could be taken. The blow-ups and other elements of such a presentation would not be ready before morning. I was satisfied that the word was going out quietly to those with an immediate need to know. The one obvious operational need was for more photography, and that was in hand.
"2. It was a hell of a secret, and it must remain one until you had a chance to deal with it. Thus everything should go on as nearly normally as possible, in particular there should be no hastily summoned meeting Monday night. Chip Bohlen and I, for example, should not leave a dinner at my house where there were knowledgeable foreign guests, and others, I knew, were in the same spot.
"3. On the other hand this was not something that could be dealt with on the phone except in the most limited and cryptic terms. What help would it be to you to give you this piece of news and then tell you nothing could be done about it till morning?
"4. Finally, I had heard that you were tired. You had had a strenuous campaign week end, returning from Niagara Falls and New York City at 1:40 Monday morning.
"5. So I decided that a quiet evening and a night of sleep were the best preparation you could have in the light of what would face you in the next days. I would, I think, decide the same again unless you tell me different." (Kennedy Library, Sorensen Papers, Cuba--Subjects Current)
Bundy prints this memorandum in Danger and Survival: Choices about the Bomb in the First Fifty Years, pages 684-685.