Launch of Discovery STS-121

[JMChladek]

I was off to the right at the press site when you were filming this. My camera picked up about the same audio quality and it really floored me to a certain extent. Fun memories of that great day.

[Connecticut2009]

GUAO MEN EXCELLECT SOUND BARRIER A 5000Miles Per Hours participent on board shuttle booster in external fuel faster un million pound in launch in TAKE OFF IN EXPECTED

[mitercut]

For sound alone, this is the best shuttle launch video on youtube! I have sub woofers and when I crank up the volume, stuff is falling off shelves, the dog is hidding, cats took off, the ole lady is screaming at me!!!! LOL!!!

[JTBarnes]

Ha Ha! Nice! I was standing just outside the Vehicle Assembly Building for that video, which is why the sound is so good. But as you can tell by the shaky video, it's like an Earthquake when that thing lift's off!

[mitercut]

That "crackling" sound is basically a repetitive sonic boom, the massive amount and speed of thrust out of the solid rocket motors are the source...

[RJY4356]

Nonsense! Supersonic speed isn't even reached until 40 seconds into flight and they sound like that all the time... ever heard a static test firing on the ground?

[mitercut]

As I stated in my comment..."Out of the solid rocket motor" not the speed of the spacecraft itself..the speed of thrust out of those solid rocket motors are many times the speed of sound (761 mph at sea level) and just like a firework salute is all that is needed to create a sonic boom...look it up.

[bschoop177]

great video! seems like u were somewhat close.. seen one a while back, but was about 65 miles away, still heard the noise and all though

[miss1jeffers2is3evil]

The reason is because when the Oxidizer is mixed with the fuel, it combusts, causing tiny explosions, but your theory was good too.

[laserfloyd]

My guess is that the gases are expanding so rapidly that the popping crackling you hear is a result of the air expanding faster than it really can? Truly amazing science. Nice video!

[djd829]

I think they are inside of a building and the sound is resonating. Like you would hear in a bathroom or something.

[laserfloyd]

I think it's just those solid rockets have that signature sound of 'popping' or 'pulsating'. Being in a building would certainly make it sound different though.

[calcmandan]

What a wonderful homemade movie. Thank you.

[atreewithnolife]

Thats the most amazing sound! what actually causes that sound? awsome vid thanks.

[laserfloyd]

Oops, replied to the video and not your comment, sorry!

[harlemdreamer]

I'd like to roast a marshmellow in that blast!

[Jeff429v]

lol! You'll probably burn your hands though :(