Author Topic: SpaceX Falcon 9 - Eutelsat 117W B & ABS 2A - SLC-40 - June - DISCUSSION  (Read 220913 times)

Offline meekGee

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FYI...


Wow - lovely - I wouldn't have imagined.  What resin is that?
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Offline CorvusCorax

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Why are the legs gone?

To answer that, we could go back in time, to May 6, 1937, Lakehurst, New Jersey.

The largest air ship ever built, the LZ129 Hindenburg - a flying Titanic, a luxury liner in the sky, marvel of an era, and kept aloft by highly flammable hydrogen -  caught fire during landing approach after a catastrophic series of events (too harsh control manoeuvres cause wires to rip - whip-slashing through the structure, damaging hydrogen cells, hydrogen accumulates under the skin, slowly diffusing through the seams while reaching explosive concentrations within - all under thunderstormy high V/m atmospheric conditions, then as the anchor cable gets lowered, there's a discharge spark --> BOOM )

The ship turned into a giant fireball in midair and crashed. But the majority of the hydrogen deflagrated in less than half a minute.

Two thirds of the people on board actually survived the crash. One third died, mostly from burns. But what killed them wasn't the hydrogen deflagration but the also burning diesel fuel that was spilled and set ablaze in the crash, while trapped in the debris. Not unlike what kills people in contemporary airline crashes. And that diesel kept burning for several hours.

The same would have happened here. We have lot's of RP-1 spilled, but no oxidizer but air. So instead of a quick RUD, we have hundreds of liters spilled on deck, pooling around the debris, and burning continuously. Applying localized heat for possibly a long duration. (The drone ship has fire suppression, but water is only of limited use against an oil fire and in the sat image 40 minutes later there was still smoke visible)

Any thermal protection on the stage, be it SPAM or cork or anything else ablative would likely have been consumed by then. The same goes for non-fire proof components of the stage. Wire insulations, hoses, possibly carbon fibre structures.

As it was burning in the open, the kerosene fire wouldn't have been hot enough to set aluminium on fire (Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?) but likely hot enough - and long enough to partially melt it, or at least soften it enough to loose its shape under its own weight and deform.

Whether the legs would have survived that depends on the thickness of material and the resin used.

This is a very informative PDF on fire behaviour or aviation carbon composites:

http://www.fire.tc.faa.gov/pdf/07-57.pdf

Continued application of an external flame source is sort of the weak point of carbon fibre structures. If the resin itself is flammable, it would burn kinda like wood, gassing out burning vapors and leaving behind an empty husk of charred fibres with no cohesion to each other. If they are also in contact with the RP-1 there might also be a wick-effect - where RP-1 is being soaked up by delaminated composites through capillary effects and burns very efficiently from its surface, like wax on a candle wick.
« Last Edit: 06/20/2016 11:23 pm by CorvusCorax »

Offline enzo

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Offline meekGee

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Cute.

But Google Aluminum.   QED. 
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Offline Rocket Science

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FYI...


Wow - lovely - I wouldn't have imagined.  What resin is that?
Not sure specifically in that video but it could be something like PyroSic, an inorganic glass/ceramic matrix. It comes from motor-sports and AAR (All American Racing) builds race cars who also happened to build the legs on Falcon. Used for turbine hot sections as well.

http://www.compositesworld.com/articles/resins-for-the-hot-zone-part-ii-bmis-ces-benzoxazines-and-phthalonitriles
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Offline chalz

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Cute.

But Google Aluminum.   QED.
According to my searching the one thing Davy never called it was Aluminium so Enzo is rude about him for no reason. And to answer Covus' enquiry I couldn't find a definitive explanation. The presumption might be that they are using Davy's settled choice - he called it Alumium initially, then Aluminum. An apocryphal alternative is that early in the life of Alcoa it was misspelled on stationary (from Aluminium) but the misspelling stuck and their dominance cemented the usage in America.

*Also you can't say QED when you have asked someone to do the work, you have to do the demonstrating. :P
*Also https://xkcd.com/386/  :-X

Offline Comga

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Cute.

But Google Aluminum.   QED.
According to my searching the one thing Davy never called it was Aluminium so Enzo is rude about him for no reason. And to answer Covus' enquiry I couldn't find a definitive explanation. The presumption might be that they are using Davy's settled choice - he called it Alumium initially, then Aluminum. An apocryphal alternative is that early in the life of Alcoa it was misspelled on stationary (from Aluminium) but the misspelling stuck and their dominance cemented the usage in America.

*Also you can't say QED when you have asked someone to do the work, you have to do the demonstrating. :P
*Also https://xkcd.com/386/  :-X

Lighten up, and can we get back on topic?
See, CorvusCorax and enzo? You can't crack nerd jokes, even good ones, around here without starting a nerd battle.
Let's just take his point and continue:  The legs were probably not incinerated, so what happened to them and where are they?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Steven Pietrobon

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Let's just take his point and continue:  The legs were probably not incinerated, so what happened to them and where are they?

The legs are still there, just badly damaged. The black object looks like a leg to me.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline rsnellenberger

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Let's just take his point and continue:  The legs were probably not incinerated, so what happened to them and where are they?

The legs are still there, just badly damaged. The black object looks like a leg to me.

I'm sorry, but you'll have to be a little more specific here...  :)

Offline Kabloona

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Quote
I'm sorry, but you'll have to be a little more specific here... 

More specifically, the black object looks like *half* a leg.  ;)

Offline Mike_1179

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Let's just take his point and continue:  The legs were probably not incinerated, so what happened to them and where are they?

The legs are still there, just badly damaged. The black object looks like a leg to me.

I'm sorry, but you'll have to be a little more specific here...  :)

Here's a before image of a leg. https://pbs.twimg.com/media/BJSV3UQCAAITfKN.jpg

Compare that to this
« Last Edit: 06/21/2016 03:05 pm by Mike_1179 »

Offline meekGee

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Cute.

But Google Aluminum.   QED.
According to my searching the one thing Davy never called it was Aluminium so Enzo is rude about him for no reason. And to answer Covus' enquiry I couldn't find a definitive explanation. The presumption might be that they are using Davy's settled choice - he called it Alumium initially, then Aluminum. An apocryphal alternative is that early in the life of Alcoa it was misspelled on stationary (from Aluminium) but the misspelling stuck and their dominance cemented the usage in America.

*Also you can't say QED when you have asked someone to do the work, you have to do the demonstrating.
*Also https://xkcd.com/386/  :-X

Lighten up, and can we get back on topic?
See, CorvusCorax and enzo? You can't crack nerd jokes, even good ones, around here without starting a nerd battle.
Let's just take his point and continue:  The legs were probably not incinerated, so what happened to them and where are they?
We're as light as an aluminium lithum alloy
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Offline psionedge

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(Anyone know the reason why is it called 'aluminum' by Americans? I mean, they don't call Strontium Strontum or Barium Barum - who misspelled Aluminium and had it stick?)
It was foolishly misspelled by the British lad who named it, Sir Humphry Davy. By the way, platinum and molybdenum called and they object to your insensitivity.

Cute.

But Google Aluminum.   QED.
Cute. But here's the google fight: http://www.googlefight.com/aluminum-vs-aluminium.php
Aluminum 100 - 14 Aluminium
Quite the shellacking...

Offline Jim

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The same would have happened here. We have lot's of RP-1 spilled, but no oxidizer but air. So instead of a quick RUD, we have hundreds of liters spilled on deck, pooling around the debris, and burning continuously.

Wrong.  It would not pool.  It is under pressure and there would still be some LOX.  It would have fireballed.  Like a rocket crashes

and in the sat image 40 minutes later there was still smoke visible)


What smoke?  It was clouds.
« Last Edit: 06/22/2016 12:55 pm by Jim »

Offline rsnellenberger

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The same would have happened here. We have lot's of RP-1 spilled, but no oxidizer but air. So instead of a quick RUD, we have hundreds of liters spilled on deck, pooling around the debris, and burning continuously.

Wrong.  It would not pool.  It is under pressure and there would still be some LOX.  It would have fireballed.  Like a rocket crashes

and in the sat image 40 minutes later there was still smoke visible)


What smoke?  It was clouds.

How much RP-1 remain in the 9 Merlin engine's regen cooling tubes after shutdown - liters, gallons?   I'm mindful of the first regen-engine Falcon-1, where the thrust from the residual fuel after shutdown was sufficient to push the first stage back into the second stage...

Offline cambrianera

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A broken nozzle would dump pressurized RP-1 into the surrounding area.
Only RP-1, not LOX.
This would explain the black smoke around the rocket, and the lack of fireball.
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Offline envy887

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How much RP-1 remain in the 9 Merlin engine's regen cooling tubes after shutdown - liters, gallons?   I'm mindful of the first regen-engine Falcon-1, where the thrust from the residual fuel after shutdown was sufficient to push the first stage back into the second stage...

Wasn't that F1 nozzle ablative and not regen cooled? Should be no RP-1 in there.

Offline whitelancer64

How much RP-1 remain in the 9 Merlin engine's regen cooling tubes after shutdown - liters, gallons?   I'm mindful of the first regen-engine Falcon-1, where the thrust from the residual fuel after shutdown was sufficient to push the first stage back into the second stage...

Wasn't that F1 nozzle ablative and not regen cooled? Should be no RP-1 in there.

The Merlin 1A and 1B (never flown) were ablative. The Merlin 1C and 1D are regeneratively cooled.
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Offline envy887

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How much RP-1 remain in the 9 Merlin engine's regen cooling tubes after shutdown - liters, gallons?   I'm mindful of the first regen-engine Falcon-1, where the thrust from the residual fuel after shutdown was sufficient to push the first stage back into the second stage...

Wasn't that F1 nozzle ablative and not regen cooled? Should be no RP-1 in there.

The Merlin 1A and 1B (never flown) were ablative. The Merlin 1C and 1D are regeneratively cooled.

Nevermind, the recontact was on a later Falcon 1 with the regen cooled Merlin 1-C. I thought it was on the second flight. Would there be enough RP-1 in the cooling plumbing to cause that much smoke?

Offline cambrianera

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http://forum.nasaspaceflight.com/index.php?topic=32983.msg1469792#msg1469792
The nozzles do have cooling passages. On one of the pics with them in the Octo you can sorta see the drain plugs (very small allen plug) near the bottom edge. As far as material and what flows in it I can't speak to that  ;)

Drain plugs circled in red. Nozzle bells are part of regenerative RP-1 flow.
Oh to be young again. . .

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