Wait, what is that old Dodge grill doing in there?
No project in the first three decades of Lockheed Skunk Works history was more stealthy, or more secret, than the D-21 reconnaissance drone. A brief history of the D-21 can be read in a previous article (click here to view).
The D-21 was made of many exotic materials, some of which are potentially dangerous to come in contact with. Many of the D-21 aircraft in museums have had their asbestos components removed. Engines are often stripped from the D-21 because they contain Mag-Thor, a magnesium alloy that includes radioactive thorium.
In 1994, NASA Dryden Flight Research Center (now Armstrong) acquired D-21 537 for hypersonic research projects that were never performed. Eventually, NASA removed the engine containing radioactive materials, so the drone could be displayed at March Field Air Museum, located on March Air Reserve Base in California.