When I lived in Biloxi - remember west of us NASA Restrictive easement area near Delisle/Diamondhead short distance off of I-10 would test rocket engines . I was amazed at the level of roar at over 40 miles away .
If someone stood 100' behind the engine when it's wide open 100% full throttle it would probably hurt your ears .
Didn't feel/hear that one, but we have in the past. It depends a lot on the atmospherics.
It's a good thing they have a big backstop, because they've blown boulders up and over that hill for more than a mile on previous tests. And as you saw, it always starts a brush fire.
In other space news, the next SpaceX launch of Starlink internet satellites is now set for tomorrow at 8:46 am Eastern. Watch that on Youtube or spacex.com
Wow, I am highly impressed. Thanks for the link. But what about all that thick, black smoke afterward? When I worked in a power plant that would have been off the charts, opacity wise and the powers that be would have went insane. But perhaps these guys don't need no stinkin' air quality regulations.
That black smoke is due to the carbon dioxide gas they inject into the nozzle at the end of firing. Did you see that long arm pivot in from the side? The nozzle gets so hot they have to quench it immediately or it will cook enough to ruin the post-test measurements. On an actual launch, when the motor burns out, it is so high that there's almost no atmosphere and it's a hundred degrees or so below zero. During a ground test, though, there's lots of oxygen. Also, the inside of the motor is insulated with thick rubber, which would also continue to burn were it not for the CO2.
I used to work on the shuttle motors, and once had to crawl inside of one. Don't worry I was told. If something goes wrong, you'll be the first one out of the building.
I also have been inside one. Spooky feeling. News photog wanted "that" shot and I had to escort him in for it. Inside, he made some smart-ass comment about his camera making a spark, and I reminded him that his cajones were inches from a million-plus pounds of rocket fuel.
When they are firing, they burn over five TONS of fuel per second, and all that fire goes out through a hole just about a yard in diameter. It holds right at 2,000 psi the whole time. The flame is 6000 degrees and it exits at about five times the speed of sound.
