In mid-1964 Northrop
Corporation was contracted by the U.S. National Aeronautics and
Space Administration (NASA) to produce two allmetal wingless
lifting body re-entry research
vehicles, based on experience gained with the Northrop M2-F1
glider, which made more than
500 flights in 1963-64. The two new vehicles were designated
M2-F2 and HL-10 (Horizontal
Landing, 10th concept) and differed in under and upper surface
fuselage shapes. First flight of the
HL-10 was on December 22, 1966 during which it had major control
problems requiring minor
changes to the shape of the vertical fins. The first 11 drop
flights from a B-52 launch aircraft were
powerless glide flights to assess handling qualities, stability
and control. The HL-10 was flown 37
times and with the use of a rocket engine reached 1,228 miles
per hour and an altitude of 90,000
feet.
The actual HL-10
craft had a width of 15 feet, was about 22 feet long and about
11 feet high
and had a launch weight of about 9,400 pounds.
The data collected during the lifting body program helped in
the development of the Space Shuttle.