Development and flight testing of the HL-10 lifting body

The Horizontal Lander 10 (HL-10) lifting body successfully completed 37 flights, achieved the highest Mach number and altitude of this class of vehicle, and contributed to the technology base used to develop the space shuttle and future generations of lifting bodies. Design, development, and flight testing of this low-speed, air-launched, rocket-powered, lifting body was part of an unprecedented effort by NASA and the Northrop Corporation. This paper describes the evolution of the HL-10 lifting body from theoretical design, through development, to selection as one of two low-speed flight vehicles chosen for fabrication and piloted flight testing. Interesting and unusual events which occurred during the program and flight tests, review of significant problems encountered during the first flight, and discussion of how these problems were solved are presented. In addition, impressions of the pilots who flew the HL-10 lifting body are given.