Columbia's first flight might well have burned up ...
From
http://www.nasa.gov/centers/dryden/p...ain_H-1894.pdf
Space Shuttle Hypersonic Aerodynamic and Aerothermodynamic Flight Research and the Comparison to Ground Test Results
[...]
Center of Pressure Location
The STS-1 showed that significantly more body-flap deflection was required to trim the vehicle hypersonically at an alpha of 40 degrees than was presicted [...].
See a.o. Page 5 and Figure 5.