The Lockheed U-2 Dragon Lady routinely operates above 70,000 feet, an altitude few aircraft can reach or sustain. At those heights the air is thin, the margins between stall and overspeed are razor-thin—only around ten knots. To engineer an aircraft capable of operating in such an environment, designers had to overcome a variety of technical challenges, to create something that carefully balanced aerodynamic design, propulsion, and materials—all while being able to fulfill a vital strategic purpose. 

The U-2 was developed in the early Cold War. The US faced a critical intelligence gap, with the Soviet Union closed to overflight, in the years before satellites existed. To better understand what was happening behind the Iron Curtain, the US needed an aircraft that could physically penetrate the air space, flying above Soviet air defenses, relying on altitude for evasion in the years before stealth existed. Altitude was the key because early Soviet SAMs and fighters operating within a limited........

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