The HL-10 lifting body, one of five designs, is seen in flight during a test.
In this historical photo from the U.S. space agency, the HL-10 lifting body is seen in powered flight shortly after launch from the B-52 "Mothership" in 1969. 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.
Each weekday, SPACE.com looks back at the history of spaceflight through photos (archive).