This non-flying, full-scale mockup of the HL-20 lifting body, used for various tests of maintainability and human factors considerations, was never built.
In this historical photo from the U.S. space agency taken on Oct. 22, 1991, the HL-20, which was built at Langley in October 1990, and is a full-scale non-flying mockup, is shown. This mockup was used for engineering studies of maintainability of the vehicle, as testing crew positions, pilot visibility and other human factors considerations.
The HL-20 was a direct derivative of the HL-10 vehicle tested in the 1960s and bears a very close resemblance to engineering drawings produced at that time. Although evaluated as a possible "space taxi," the HL-20, sometimes called the "Personnel Launch System," was never built.
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