Experts said protrusions on the otherwise smooth belly of the shuttle could disturb the air flow during re-entry, causing turbulence that raises temperatures on heatshield tiles downstream.
Even before the mid-air collision over the South China Sea caused more turbulence in Beijing-Washington relations, the arms issue was making its own waves.
They found that gravity waves "break" on the surfaces of planes, just like ocean waves breaking on the beach, causing much of the turbulence that occurs out of the blue in clear air.
Air France has said that Flight AF 447 sent an automatic signal indicating electrical problems while going through strong turbulence early in its 11-hour flight from Rio de Janeiro to Charles de Gaulle airport in Paris.