Sonic flight without the boom

> Seeing how the discussion has been much about the physics of supersonic 
> shockwaves, does anyone know how NASA performed this sonic boom 
> attenuation?
> 
> http://spaceflightnow.com/news/n0309/06supersonic/

Exactly how the article says they did it: They optimized the 
shape of the aircraft to alter the ground-level overpressure profile 
such that it minimized the perceived "loudness" of the boom at cruise 
speed and altitude. (Qualitatively, it is not much different 
from optimizing the shape of a boat to minimize its wake-drag.)


-- Gordon D. Pusch