The HL-10 lifting body is seen here in powered flight shortly after launch from the B-52 'Mothership'. The HL-10 was one of five lifting body designs flown at NASA's Dryden Flight Research Center, Edwards, California, from July 1966 to November 1975 to study and validate the concept of safely maneuvering and landing a low lift-over-drag vehicle designed for re-entry from space. Ultimately, the lifting body design proved too difficult to control. It had a high landing speed. The design was not used for the space shuttle.