Project GENETRIX | The CIA's Army of Spy Balloons Over the Soviet Union

Between January and February 1956, the US Air Force and the CIA launched more than 500 unmanned balloons, each carrying a camera across the Soviet Union and China.

They called it Project Genetrix, officially designated WS-119L, and it remains one of the odder gambles of the early Cold War.

It was a plan to solve America's blindness about Soviet military strength, and this was done not with a spy or a plane, but with hundreds of silver spheres drifting wherever the jet stream took them.

It lasted 27 days.

It produced a diplomatic humiliation that was broadcast to the world's press.

And, almost by accident, it helped build the two programs that would actually win the intelligence war that followed.

This is that story.

By the mid 1950s, American planners faced what the CIA called a profound intelligence deficit.

The Soviet Union was, in Churchill's phrase, a riddle wrapped in a mystery inside an enigma.

A closed society that barred foreign observers and, above all, forbade anyone from flying over it and looking down.

American analysts had expected the Soviets to need years longer to build an atomic bomb.

But thanks to spies like Klaus Fuchs, David Greenglass and Julius Rosenberg, the Soviets were able to test their first device, the RDS-1, in August 1949.

That was well ahead of the American estimate.

Now, with the Soviets having nuclear capability, the worry was not only the missile gap, but also the means by which the adversary might deliver a nuclear payload.

US President Dwight D Eisenhower was desperate to know how many bombers Nikita Khrushchev really had.

He tried the honest route first.

At the Geneva summit in July 1955, Eisenhower proposed open skies.

This was intended as an agreement for mutual aerial inspection.

In other words, each superpower would be free to photograph the other's territory.

Of course, Khrushchev rejected it.

The balloons were already in development by then.