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Guided systems and the Pigeon project

Aeronautical history is full of initiatives, experiments and developments that, seen from the perspective of time, seem unbelievable. But there they are. In fact, it never ceases to be surprising how the human mind is capable of coming up with the most bizarre ideas in times of crisis and, especially, in times of war. A clear example of this was the project called “Project Pigeon”, developed by the United States during World War II with the aim of advancing in the field of guided systems.

The use of pigeons to guide bombs during the last world war seemed like a pipe dream, until its viability and efficacy were demonstrated.

Regrettably, wars are generally a field in which technological development explodes exponentially. When at war, being one step ahead of the opponent can make all the difference, and having a testing ground for less humane ideas is relatively easy.

During World War II, achieving a guided bomb became a holy grail. Computers were still large, heavy machines that were impossible to introduce into any type of bomb. In 1943, the United States, in its quest for a bomb guidance system that was more precise than traditional methods, contacted psychologist and inventor Burrhus Frederic Skinner, and awarded him a contract that went by the name “Project Pigeon”.

Years earlier, Skinner had contacted the National Inventors Council to demonstrate the progress he had made in pigeon research. However, it seems that at the time he did not raise enough interest for the national defence agency.

Skinner’s idea was to put pigeons in the nose cone of bombs so that, by means of a screen, a control device and proper training, they would be able to guide a bomb to a certain target, thus becoming kamikaze pigeons. On paper, a trained pigeon was a much better choice than a human being for this particular task. They have better vision and ability to react than humans, in addition to other advantages: they are able to differentiate colours, do not get dizzy and are smaller in size.

The project had two challenges to overcome. The first was the complete training of the birds, which were subjected to different tests and phases. The second major challenge was the development of the compartment and control device for the bomb.

The training started with a squadron of 64 pigeons. The target for the real tests was to be a white triangle on a green field located in Florida. Skinner therefore left the birds 36 hours without food, and then put them in a box and showed them white triangles on green paper. This was associated with the delivery of a few grains of food. It did not take the birds long to make the association, and they started pecking on the white triangle with such ferocity that stronger sheets of paper had to be used.

In the next phase, a projector was devised with an image of the moving target on a projection screen (in other words, a mini-cinema for pigeons). The screen had an electrical mechanism that, when pecked on, opened a trapdoor and dropped a few grams of food. This worked until the birds realised that it didn’t matter what part of the screen they pecked on, it always opened the trapdoor that provided them with food. Skinner resolved this problem by introducing a double beam of light at right angles to the target, so that the peck would have to break both beams in order for the pigeon to get its coveted prize.

They then tried to teach the birds consistency. Thus, they were not fed unless they had made a minimum number of pecks on the target. This resulted in an intensity of four pecks per second for two minutes, which would ensure constant guidance of the supposed bomb.

The final test consisted of an operator with an image that moved manually, so that the pigeons could not follow the patterns of the projected images, but rather they had to perform the real and totally random exercise.

The 64 pigeons that underwent the training excelled.

In addition to all the previous phases, the pigeons were subjected to physical tests that could stun them or divert them from their objective, as could happen in a real battlefield: from flares and flashes, to noises of nearby explosions, pressure variations, vibrations, pure oxygen, changes in G forces using centrifuges (like astronauts do), and so on.

On the other hand, the bomb’s nose cone was designed as a compartment that could house three, five or seven birds, each with a screen linked to the screens of the other pigeons, and in turn, mechanically connected to the bomb’s aerodynamic control surfaces. In this way they could ensure that if any pigeon deviated from its duty, the rest could continue to guide the bomb. Keep in mind that, because it was a mechanical system, it required coordination and depended directly on the force of the pecking they developed.

As a final test, with the bomb’s nose cone designed, it was decided to intersperse male pigeons with female pigeons to observe if at any time either gender abandoned its task. This, however, did not occur. The birds carried on performing their task perfectly, demonstrating that the 36 hours of fasting carried more weight than any other animal desires.

When enough research had been done, Skinner was invited by the Office of Scientific Research and Development to carry out a demonstration in Washington, D.C. The demonstration was a complete success. However, in 1944, and to the pigeons’ great relief, the project was cancelled under the pretext of earmarking funds for more immediately applicable research. What’s more, by the end of 1943, the Germans had once again taken the lead by carrying out a radio-guided bomb attack.

Today, Skinner’s bomb prototype is on display at the National Museum of American History in Washington, D.C. Skinner decided to keep the pigeons he had trained so dedicatedly. Later, he subjected them to the same tests, years after having completely ceased training. The pigeons once again managed to hit the target, demonstrating that the psychologist’s work had been worthwhile.

 

 

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08/04/2019

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