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My heart attack moment was during the launch when I started seeing flame flickering around the tops of the engines... and then I thought to look at the altitude

My heart attack moment was during the launch when I started seeing flame flickering around the tops of the engines... and then I thought to look at the altitude indicator, and realised they were at about 10km, and it was just the plume expanding as the atmospheric pressure dropped.

Flame 10y ago
I got extremely worried when I saw that happen too. I didn't even think to look at the altitude indicator.
- vmasto 10y ago
  I got extremely worried as well and it wouldn't have made a difference looking at the altimeter because I have no idea about how rocket engines behave.
tdy721 10y ago
The flames around the top of the engines is normal, it's the exhaust from the turbo pumps feeding the main engines. Check this page, the Merlin uses an open cycle, where fuel/oxidizer used to fuel the pumps is just dumped overboard. https://en.wikipedia.org/wiki/Gas-generator_cycle https://en.wikipedia.org/wiki/Gas-generator_cycle This picture clearly shows both exhausts: https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)#/media/File:SpaceX_Testing_Merlin_1D_Engine_In_Texas.jpg https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)#...
- jacquesm 10y ago
  For some reason that effect was much more pronounced during this flight (at least in the video) than in previous launches that I watched. Maybe it was because of the camera angle looking more at the side of the rocket when usually you are looking more at the bottom.
- lutorm 10y ago
  Yeah, it's normal, and it usually ends up getting sucked backward, presumably due to the turbulent airflow in the space between the end of the vehicle and the engine nozzles: Echostar: https://youtu.be/zEfEBJfD_RE?t=18m23s https://youtu.be/zEfEBJfD_RE?t=18m23s JCSAT: https://youtu.be/QZTCEO0gvLo?t=17m38s https://youtu.be/QZTCEO0gvLo?t=17m38s CRS-9: https://youtu.be/ThIdCuSsJh8?t=17m45s https://youtu.be/ThIdCuSsJh8?t=17m45s

Flame 10y ago

I got extremely worried when I saw that happen too. I didn't even think to look at the altitude indicator.

vmasto 10y ago
I got extremely worried as well and it wouldn't have made a difference looking at the altimeter because I have no idea about how rocket engines behave.

tdy721 10y ago

The flames around the top of the engines is normal, it's the exhaust from the turbo pumps feeding the main engines. Check this page, the Merlin uses an open cycle, where fuel/oxidizer used to fuel the pumps is just dumped overboard. https://en.wikipedia.org/wiki/Gas-generator_cycle https://en.wikipedia.org/wiki/Gas-generator_cycle This picture clearly shows both exhausts: https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)#/media/File:SpaceX_Testing_Merlin_1D_Engine_In_Texas.jpg https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)#...

jacquesm 10y ago
For some reason that effect was much more pronounced during this flight (at least in the video) than in previous launches that I watched. Maybe it was because of the camera angle looking more at the side of the rocket when usually you are looking more at the bottom.
lutorm 10y ago
Yeah, it's normal, and it usually ends up getting sucked backward, presumably due to the turbulent airflow in the space between the end of the vehicle and the engine nozzles: Echostar: https://youtu.be/zEfEBJfD_RE?t=18m23s https://youtu.be/zEfEBJfD_RE?t=18m23s JCSAT: https://youtu.be/QZTCEO0gvLo?t=17m38s https://youtu.be/QZTCEO0gvLo?t=17m38s CRS-9: https://youtu.be/ThIdCuSsJh8?t=17m45s https://youtu.be/ThIdCuSsJh8?t=17m45s