Nearly 93 percent of the Blackbird skin and structure is titanium, a metal twice as strong as aluminum and only 60 percent heavier. Besides strength, it has a high melting point-over 3,000 degrees-so the SR-71 skin kept its shape when it reached 600 degrees at Mach 3. Despite these virtues, the metal is difficult to work; Lockheed had to invent methods to shape it precisely. The CIA procured the metal for the spyplane from one of the countries it intended to spy on: the Soviet Union. Today, Russia is a major processor of titanium, but not a major source of the ore. (Australia, South Africa, and China are.)
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