Right then, piece of foam insulation comes loose - a rather fragile piece of material even with a hard backing - perhaps more fragile than insulating tiles (ceramic?) - enters slipstream and decelerates from launch vehicle speed of around 500 mph - or something certainly below the speed of sound at that point. Foam is likely to fragment in violent slipstream - if it doesn't it indicates impact in a second or two lessening speed of impact. Full piece or fragment thereof strikes leading edge of wing at something less than vehicle speed. Test indicated foam fired at test tiles at 500 mph. Still don't understand.