The view from the American side.
Sergei Khrushchev repeatedly insists that Soviet leaders were stunned and scandalized by America’s behavior, from the first U-2 flight in 1956 to Elsenhower’s lack of apology or conciliation in 1960. However, U-2 is pronounced “you too,” and such a riposte is appropriate.
Within the United States, Soviet espionage predated World War II. Stalin began by setting up a trading organization, Amtorg, that acted as a front for theft of industrial secrets. During the war, Soviet agents penetrated the heart of the Manhattan Project and made off with some 10,000 pages of technical material, all of which reached Moscow safely. Igor Kurchatov, who headed the Soviet atomic-bomb effort, made good use of these secrets. His first nuclear reactor closely followed an American design, except for being larger to compensate for the lesser purity of his uranium. The first Soviet atomic bomb, detonated in 1949, amounted to a copy of the Fat Man plutonium bomb dropped on Nagasaki four years earlier.
The U-2 was not the first American spy plane to overfly the Soviet Union. Gen. Curtis LeMay, head of the Strategic Air Command, had started by using B-45 and B-47 bombers. He later recalled a time when “we flew all of the reconnaissance aircraft that SAC possessed over Vladivostok at high noon.” This was Moscow’s principal Pacific naval base. However, those bombers were vulnerable; the U-2 flew much higher, which is why it took years before the Russians could knock it out of the sky.
Following an initial flurry of U-2 flights, during July 1956, Soviet diplomatic protests forced a stand-down. The next four years brought fewer than twenty subsequent overflights, each requiring personal authorization from President Eisenhower. Even so, their photography proved highly significant.
In 1956 there was considerable concern over a “bomber gap,” with which Moscow might take the lead in producing long-range jet aircraft. One of the first U-2 missions produced photos that showed far fewer heavy bombers than expected. The “bomber gap” vanished.
The 1960 U-2 incident brought an end to overflights of the Soviet heartland, but from the outset the CIA had regarded the U-2 merely as an interim craft, ultimately to be superseded by spacecraft. The Soviets had similar thoughts. They never built highflying aircraft to rival the U-2, but they actively pursued reconnaissance satellites.
The standard Soviet spacecraft of this type was Zenit (“zenith”). A variant, Vostok (“east”), carried the first cosmonauts into space, in 1961. The CIA’s Discoverer spacecraft, supplanting its U-2s, also entered operational service during 1960.
Through the subsequent decades of the Cold War, both superpowers continued to build and fly reconnaissance satellites. Significantly, although they might have deployed anti-satellite weapons, they declined to do this. In both Moscow and Washington national leaders decided that they had more to gain from free mutual observation, avoiding destabilizing surprises. In this fashion, without formal diplomatic agreement, both superpowers accepted Eisenhower’s Open Skies proposal as a basis for their ongoing rivalry.