Saturday, October 27, considered the longest day of the crisis, began with intelligence indicating that three of the four medium-range ballistic missile sites at San Cristóbal and another two at Sagua la Grande were now operational. This was followed by news from Secretary of Defense Robert McNamara that low-altitude flights over Cuba were now taking fire, followed shortly by news of an even more disturbing incident intercepted from Radio Havana – that a U-2 pilot was shot down and killed over Cuba. NSA immediately began sorting through data, even as representatives from the Joint Chiefs of Staff rushed to NPIC to review the flight plan in question against the latest imagery. Within hours, it was confirmed that Major Rudolph Anderson’s U-2 had been brought down by the Los Angeles SA-2 missile site near Banes, Cuba.
That night, expecting the worst, final preparations were instituted across the U.S. for a war that seemed increasingly inevitable. Marine brigades began boarding ships bound for invasion staging areas, thousands of Air Force reservists were told to report to their active-duty stations and U.S. destroyers patrolled Soviet submarines in the Atlantic. At Andrews Air Force Base, transport aircraft were being readied to evacuate casualties that would result from an invasion of Cuba and military hospitals prepared to receive the wounded.
On the morning of Sunday, October 28, the Soviets alerted the U.S. embassy that a formal diplomatic letter was on its way. At 9:09 ET, a brief teletype was received from the Foreign Broadcast Information Service, stating: “Moscow Domestic Service in Russian at 1404GMT on 28 October, Broadcast a message from Khrushchev to President Kennedy stating that the USSR had decided to dismantle Soviet missiles in Cuba and return them to the Soviet Union 28 October 908a-FRR/HM.”