North American X-15A-2
North American X-15A-2 on display in the National Museum of the U.S. Air Force Space Gallery.The X-15 was an important tool for developing spaceflight in the 1960s, and pilots flying above 50 miles altitude in the X-15 earned astronaut wings. (U.S. Air Force photo by Ty Greenlees)

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Photo by: Ty Greenlees |  VIRIN: 210914-F-AU145-031.JPG