In the late 1950s, the U.S. Central Intelligence Agency (CIA) sent U2 spy planes to photograph secret locations in the former Soviet Union. The Lockheed U2 were flying at an altitude of 70,000 ft, out of the reach of whole fire and radar.
These extraordinary devices were more than reaction gliders built with plastic and triplay. After takeoff, the wheels were detached from the end of the wings. They landed with the main landing gear, integrated in their fuselage.
It wasn't until May 1960, after more than four years of flights, that the Russians shot down a U2, using modern radar equipment used in SA-2 anti-aircraft missiles. Even so, the U2 did not receive the impact directly: a projectile exploded very close and launched it in an uncontrollable dive. The pilot, Gary Powers, had to jump off the ship.
The success of U2 prompted the United States to undertake an ultra-secret investigation called Stealth, with the aim of manufacturing military devices that were undetectable to radar.
The U2 spent so much time unnoticed because it was made of non-metallic materials that absorbed radar waves, rather than reflecting them to the ground station, as is often the case.
The Stealth programme aimed to design high-performance military aircraft, made of a minimum of metal and with the exterior coated with a radar wave-absorbing layer. This would outwit most anti-aircraft systems.
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