IV.

Lifting Bodies

Experimental craft called lifting bodies were investigated in the late 1960s as potential space vehicles that would allow astronauts to glide in from outer space. The United States Air Force and the National Aeronautics and Space Administration (NASA) studied designs for a space vehicle that would acquire lift as it hurtled into the atmosphere of the earth and could then be maneuvered to a desired landing zone. Because conventional wings would snap off such a craft as it entered the atmosphere at high speed, the entire undersurface of the craft had to function as a lifting surface. This is the source of the term lifting bodies.

The lifting body program was started in the late 1950s. At that time NASA started experimenting with the M-2 and later with the HL-10 lifting bodies. These vehicles were dropped from B-52 bombers at high altitudes and they glided to earth without power but with aerodynamic control. In the late 1960s the air force tested the X-24 lifting body. Rocket engines on this craft pushed its speed up to about 2,200 km/h (about 1,350 mph). At that speed, the descent of the X-24 simulated a gliding reentry from space. Information gained in these tests was used to help design the space shuttle, which lands on the earth after a mission by gliding through the atmosphere (see Space Exploration).