Author Topic: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD (1)  (Read 1177642 times)

Offline RoboGoofers

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #620 on: 09/01/2016 09:28 PM »
That is exactly my point though, the mixture isn't right. They are totally separate until something goes wrong. It seems a stretch to think the O2 tank popped, which popped the RP-1 tank, and static happened at the right time and place to cause a spark, all within a few milliseconds. We should have seen a tank pop before it all went up.

That's what i believe too.

At least with a copv bursting, it would send shrapnel through the tank walls into the fuel tank causing mixing.  someone mentioned upthread that the bursting of a copv might have enough energy to start the chemical chain reaction (not the kind of "classical" ignition source you'd imagine like a flame or spark), and the copv carbon would be flammable in a high oxygen environment.

« Last Edit: 09/01/2016 09:30 PM by RoboGoofers »

Offline Carl G

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #621 on: 09/01/2016 09:29 PM »
A reminder, stupid posts will be deleted. Rumors from other sites that are stupid will be deleted. Members insisting on posting such things will be banned. People complaining there's speculation on here will also have their posts removed before this is the discussion thread, not the update thread. The update thread is for the official info.

Offline clegg78

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #622 on: 09/01/2016 09:29 PM »
Wouldn't the color of the initial detonation (orange) suggest an RP-1 leak?

I was thinking the same,  Its not like there was a gush of white vapor (LOX) that lead to an ignition/detonation.   IT was clearly orange fire initially (although energetic and obviously merged with LOX for the big boom at the top).
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Offline Jim

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #623 on: 09/01/2016 09:30 PM »

Please... This is an incessant problem on this forum to attribute new failures to previous issues. In engineering its the exception rather than the rule that a new failure is the same failure as before. If something fails its almost certainly something else that failed unless your engineers have no clue what they're doing or root cause was not found. This failure is NOT going to be related to struts. Forget the struts exist. That's a solved problem. Different metal suppliers, different stronger design, additional struts, impossible to be the same problem.

I dunno, ever heard of Taurus, OCO, and Glory? Just saying...

AC-70 and AC-71.
« Last Edit: 09/01/2016 09:30 PM by Jim »

Online mlindner

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #624 on: 09/01/2016 09:30 PM »
Accidentally (or deliberately) activated FTS would have activated the FTS for the entire vehicle, not just the second stage.  This failure was too localized to be FTS.
That exactly looks like what happened. The whole stack just exploded really fast.

It really didn't.  There was a localized explosion in the second stage with a relatively slow progressive failure down the stack.  If it was FTS, the whole vehicle would have ceased to exist in the span of two or three frames.

FTS isn't designed to obliterate the vehicle as much as it is to release the fuel to get rid of its mass, momentum, and explosive potential. When we've seen FTS before it causes a slow conflagration fireball just like we see here after that initial pop at the top of S2. It looked very much like the fireball we saw on GH2, although with a much better vantage point to see details.

For those saying FTS wouldn't cause a fireball, well, what other ignition source was there? We didn't see a green flash.

FTS is designed to cease acceleration and disperse the propellants.  This is often accomplished by a linear shaped charge running the length of the vehicle.  I suspect the Falcon is the same way.  You might not see an immediate fireball, but you would see the whole vehicle unzip basically at once if it were FTS, not the several seconds it took to completely come apart.

I'm somewhat doubting this theory now personally, but the upper stage and bottom stage necessarily have to be on different FTS circuits. What we indeed see is a sudden destruction of the upper stage and the contained liquid fuel of the upper stage falling to the ground and then an explosion indicative of the rupture of the lower stage followed by the impact at the bottom causing complete rupture of the lower stage and subsequent explosion.
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Offline acsawdey

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #625 on: 09/01/2016 09:31 PM »
The vehicle is sitting in a cloud of concentrated, evaporating oxygen and is holding thousands of kilograms more on board. A small leak and a spark is all that is needed to cause an event big enough to rupture the tanks leading the chain reaction. Oxygen is abundant in this scenario - we don't need an explosive to turn the situation bad.

someone posted this upthread, but lot of fuel and LOx mixing without an explosion: Atlas 190D



Quote
13,000 gallons of liquid oxygen and a full load of fuel sloshed over the stand and the nearby terrain.

here's a reference:
https://books.google.com/books?id=OVNuxBlXFHYC&lpg=PA32&ots=RWbZyy0by-&dq=1963%2C%20Atlas%20190D&pg=PA32#v=onepage&q=1963,%20Atlas%20190D&f=false

Atlas 190D had only fuel on board no LOX:

Quote
The launch crew managed to
drain the LOX tank but ended up depressurizing it in the process, and so
it collapsed, dropping the Agena.

http://www.spacebanter.com/showthread.php?t=51063

Offline eeergo

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #626 on: 09/01/2016 09:32 PM »

That is exactly my point though, the mixture isn't right. They are totally separate until something goes wrong. It seems a stretch to think the O2 tank popped, which popped the RP-1 tank, and static happened at the right time and place to cause a spark, all within a few milliseconds. We should have seen a tank pop before it all went up.


The RP-1 tank is pressurized too. A sudden catastrophic loss of pressure from the top tank (coupled with the immediate boiling and aerosolization of the remaining LOX) would have caused a very traumatic upward force event for the common bulkhead to withstand, causing it to fail upward and providing a kerosene spray from below. This, provided the bulkhead hadn't failed beforehand, causing the visible wall rupture.


A burning RP-1 stream starts to appear in the image (see arrow) at frame 10 after the explosion already: around 160 ms after the explosion started.
« Last Edit: 09/01/2016 09:46 PM by eeergo »
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Offline MattMason

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #627 on: 09/01/2016 09:33 PM »
That is exactly my point though, the mixture isn't right. They are totally separate until something goes wrong. It seems a stretch to think the O2 tank popped, which popped the RP-1 tank, and static happened at the right time and place to cause a spark, all within a few milliseconds. We should have seen a tank pop before it all went up.

That's what i believe too.

At least with a copv bursting, it would send shrapnel through the tank walls into the fuel tank causing mixing.  someone mentioned upthread that the bursting of a copv might have enough energy to start the chemical chain reaction (not the kind of "classical" ignition source you'd imagine like a flame or spark), and the copv carbon would be flammable in a high oxygen environment.

And if either tank burst, logic suggests the integrity of the second stage would've failed far more quickly and the payload fairing would've fallen or been pushed away much earlier.
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Offline glennfish

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #628 on: 09/01/2016 09:33 PM »
I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached
« Last Edit: 09/01/2016 09:34 PM by glennfish »

Offline Lar

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #629 on: 09/01/2016 09:38 PM »
Deleted a couple of "what is this thing transversing the vid" ... it's a bird.

People, it's fun to speculate but please review the thread before you post, and think. At least a little.
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Offline Space Ghost 1962

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #630 on: 09/01/2016 09:38 PM »
I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached

Interesting. Can be ballistically reconstructed. Anyone up for this?

Offline atsf90east

I noticed this too.  I'm not familiar with the LOX fill line interface with the vehicle, but if the explosion started inside the second stage, wouldn't this object be blown outward, and not upward?

I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached
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Offline TheTraveller

So what is Object X?
« Last Edit: 09/01/2016 10:01 PM by TheTraveller »
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Offline MattMason

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #633 on: 09/01/2016 09:44 PM »
I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached

Interesting. Can be ballistically reconstructed. Anyone up for this?

I'm sure you're asking the right people, if NSF's CRS-7 forum investigation and F9 water landing video reconstruction are any indications. :)
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Offline dorkmo

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #634 on: 09/01/2016 09:46 PM »
So what is Object X?

i think what you circled on the left side is some liquid oxygen that is being pushed away

and what you circled on the right side is the claw that holds onto the stage that is part of the Erector

Offline RoboGoofers

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #635 on: 09/01/2016 09:47 PM »
I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached

it could also coming toward the camera.

Offline bstrong

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #636 on: 09/01/2016 09:48 PM »
So what is Object X?

That's what I was calling evidence of the LOX tank rupturing at top left, near the vents.

Offline Wolfram66

So what is Object X?

i think what you circled on the left side is some liquid oxygen that is being pushed away

and what you circled on the right side is the claw that holds onto the stage that is part of the Erector

Correct. That is simply a backlit O2 vapor cloud. move along...

Offline dorkmo

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #638 on: 09/01/2016 09:49 PM »
I think there's evidence that the explosion initiated to the side of the rocket, not on or in the rocket.  The USLaunchReport video as a reference.   There is a fragment that has a trajectory that traces back to the strongback, not the rocket.  Reference images attached

it could also coming toward the camera.

also spinning as it is catching different light from the flame

Offline ChrisWilson68

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Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #639 on: 09/01/2016 09:53 PM »
WOW. We can see the payload fall seconds after the first explosion. Maybe a dragon could fly away in time.

Maybe the crew Dragon but not the cargo Dragon. The cargo Dragon can now survive a CRS-7 type accident by deploying its parachutes but that doesn't help if the accident is at the pad.

It's hard to know if people would have survived if they had been in a crew Dragon on this rocket.  If there was no warning, the Dragon would have been subjected to a significant overpressure before it could have taken off.  Maybe the Dragon could have protected crew members from such an overpressure, maybe not.

There's also the issue of whether the overpressure would have damaged the SuperDraco engines and/or their prop tanks and/or the abort control system.  If any of those things failed, the crew would have died.

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