Air density reaches critical mass at the speed of sound.

Imagine rotating the above animation 90 degrees counterclockwise so that the vehicle is traveling upward and vertical. Observers on the ground in the vicinity of the launch site are intersected by the sound waves, but the waves are spread out in time and space and won't produce a boom like the surface of the Mach cone does. The surface of the Mach cone may never intersect them.

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An observer at some altitude and near the vicinity of the shuttle launch would probably get intersected by the surface of the cone and hear the boom if it wasn't drowned out by all the rocket motor noise.

For a vertical launch, the drop in air temperature and pressure with altitude can bend the path of the sound waves and distort the shape of the Mach cone in such a way that it might bend outward or even upward, which would aid in the surface of the cone not intersecting anyone at or near the ground level.

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Or That's correct!!!

 

Having never actually been to a shuttle launch I'd never considered it from the perspective of a ground observer.

 

Take a look at this nice video of a shuttle launch shot by someone on a commercial flight.

https://www.youtube.com/watch?v=Xv5J5cBwwFc"]YouTube- Space Shuttle Launch view from commercial flight!

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I didn't specifically say a ground observer in my first post when I should have. The boom occurs every shuttle launch somewhere but not necessarily at the ground level.

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I hadn't considered that the effect would be confined to the surface of the cone. Thanks.

 

I imagine myself as a point somewhere in near spatial relation to the aircraft (spacecraft)

like third person flight simulator kinda stuff.

it informs the way I view things.

 

Regarding the cloud formation that envelops part of the aircraft, I expect it to be the result of a drop in air pressure near the aircraft and the associated drop in air temperature (rather than occurring at the point of a pressure buildup). That could bring the temperature of humid air below the dewpoint and cause water condensation, much like it does in ordinary weather when the temperature drops below the dew point and fog develops.

Those clouds are associated with transonic flight but they can also occur during subsonic flight. High relative humidity (dewpoint just below ambient temperature) probably favors their formation during subsonic flight.

Here's a pic of one of those clouds on a commercial passenger jet near the ground level and traveling well below the speed of sound.




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the jet is traveling well below the speed of sound, but it is both distinctly possible that the air in that part of the stream over the aircraft is traveling much faster than the jet as a whole (brakes, spoilers, flaperons <NOT THE PROPER NAME> all account for this sour of thing in landing, this plane looks like it's taking off though)

could also just be fucking high humidity, so the pressure drop (which it is, the pressure differential causes material to move faster than thermal energy can) is just less.