Thsi project was started in 1957 by Boeing. The X-20 was designed to provide a piloted, maneuverable vehicle and associated equipment for coducting
experiment in the hypersonic and orbital flight regime. It was designed like the OSP. It never got past the mockup stage though. Some of the
vehicles that were considered to lift the X-20 into space were the Titan, Atlas, Minuteman, Saturn, and Phoenix. Here are some specs.
Length: 35ft 4in
Wingspan: 20ft 5in
Wing area: 345 sq ft
Height: 8 ft
Accommodation: 1 person
Gross weight: 11,390 lb
Empty weight: 10,830 lb
Max altitude: 555,000 ft
Range: 19,000 + miles
Max speed: 16,670 mph
This was an interesting project jetsetter. I used to see displays of this when I was a kid and went to air shows. I think, by the look of it, that it
was the grand father of the space shuttle.