Flown 37 times by NASA's Flight Research Center at Edwards. First flight 12-22-1966, final flight 7-17-1970. Maximum speed and altitude records held by the HL-10: Mach 1.86 (1228 MPH) and 90.300 feet. The HL-10 was part of a program that investigated blunt-shaped vehicles, called lifting bodies, which led to the selection of a lifting entry configuration for the Space Shuttle. Results from the lifting body flights greatly aided shuttle designers in the decision to land the orbiter as an unpowered glider.