Author Topic: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD (1)  (Read 1190852 times)

Online dglow

  • Full Member
  • ****
  • Posts: 835
  • Liked: 659
  • Likes Given: 1649
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #560 on: 09/01/2016 07:24 PM »
I think Kabloona might be onto something.
I hear three distinct "initial" sounds:

1:16--a very faint "plonk" like someone hitting a PVC pipe with a hammer in the distance...COPV rupture?
1:18--a faint pop/bang... S2 tank rupture?
1:23--very loud boom...the LOX/RP-1 explosion?

That first sound at 1:16 is unusual and seems to me like it may be the initiating event. A COPV or high pressure line/fitting letting go followed by S2 tank rupture 1-2 seconds later seems consistent.
Crank up the volume, the first sound could be the creak of metal bending. If that's the case, we might be hearing a strut bend and break, a COPV rupturing or helium hose popping, and the loud boom is the visible explosion.

The camera and mic are over 2.5 miles from the pad. We don't know what kind of microphone was in use. Other than the explosion itself, we don't know where those other sounds originated from.

There's a voice that precedes the explosion by several seconds – where was that coming from? I hear what sounds like someone inhaling or gasping right at the point where they would have seen the explosion – but not heard it yet.

To my ears, the faint 'plonk' sounds decidedly sharper and nearer to the camera than the explosion which follows. Again, wild speculation: we don't know the limitations of this recording.

Still, many thanks to USLaunchReport for sharing this video.   :D

« Last Edit: 09/01/2016 07:32 PM by dglow »

Offline Oersted

  • Member
  • Full Member
  • ****
  • Posts: 987
  • Liked: 598
  • Likes Given: 319
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #561 on: 09/01/2016 07:34 PM »
Will this lead to new SpaceX procedures for quick 'n easy mating of the payload after static test firing? Should make for more aggressive, safety-enhancing testing.
« Last Edit: 09/01/2016 08:11 PM by Oersted »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32484
  • Cape Canaveral Spaceport
  • Liked: 11259
  • Likes Given: 333
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #562 on: 09/01/2016 07:38 PM »
Will this lead to new SpaceX procedures for quick 'n easy mating of the payload after static test firing. Should make for more aggressive, safety-enhancing testing.

Not really.  Still constrained by what the payload needs to do after mate.

Offline CJ

  • Full Member
  • ****
  • Posts: 887
  • Liked: 649
  • Likes Given: 180
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #563 on: 09/01/2016 07:45 PM »
I'm going to speculate wildly here (Mod, please delete if inappropriate);

Point 1; The CRX7 failure occurred in the second stage.
Point 2; This explosion *appears* to have originated in the second stage.

Speculation: to my eyes, this event appears to have been highly energetic from the first moment it appears.

Further speculation; would a COPV failure (sudden release of He into the LOX) fit observations? In other words, one of the COPV He tanks ruptures, resulting in massive overpressure of the LOX, leading to massive and sudden structural failure thereof, and thus an explosion as the LOX mixed with RP1, with ignition sources provided by the structural failure/electrical umbilical?

If the above is true, is point 2 significant (perhaps a COPV, not a strut, caused CRX7?) Or could a strut failure have caused today's explosion? 

One possible silver lining here; the debris to investigate are in a small area on land, not scattered on vast stretches of seabed.

Edit to add; what about lightning? I think we'd have seen a lightning strike, would we would not have seen a step/leader, which is more than enough to fry a human, and thus plenty to cause sparking. Any idea what the electrical field strength was? (I'm probably flat out wrong here, because the scrub limits for a static fire are probably the same as for a launch when it comes to lightning.)

 
« Last Edit: 09/01/2016 07:51 PM by CJ »

Online RotoSequence

  • Full Member
  • ****
  • Posts: 1095
  • Liked: 777
  • Likes Given: 877
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #564 on: 09/01/2016 07:47 PM »
Whatever the anomaly was that destroyed the launch vehicle, it was very energetic.  ???

Online PahTo

  • Full Member
  • ****
  • Posts: 1545
  • Seattle
  • Liked: 175
  • Likes Given: 568
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #565 on: 09/01/2016 07:51 PM »

Thanks for posting the video.  Boy, watching the payload tumble to the ground/from the cradle after the fact sure adds insult to injury...
Again, my thoughts are with all involved.  Glad there weren't any injuries (any followup to reports that a firefighter was injured?)

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4334
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2563
  • Likes Given: 531
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #566 on: 09/01/2016 07:58 PM »
The flame in the first frames looks more characteristic of detonation than conflagration to my amateur eyes; it's sharp and white all around.

That may just be sensor saturation. A better indicator of detonation is wave speed. If that had been a high order detonation, the stage would just disappear in one frame. The relatively slow development of the fireball is more characteristic of conflagration.

Edit: or per below post, the sharp white " flame" is just interpolation, not actual footage.
« Last Edit: 09/01/2016 08:01 PM by Kabloona »

Online RoboGoofers

  • Full Member
  • ***
  • Posts: 333
  • NJ
  • Liked: 168
  • Likes Given: 244
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #567 on: 09/01/2016 07:58 PM »
These screen shots were posted by @John_Gardi on Twitter.  Taken from this slow-mo video.

The Slo-mo frames are just interpolated from the existing frames, so it's impossible to conclude anything from them.

Offline mme

  • Full Member
  • ****
  • Posts: 1302
  • Santa Barbara, CA, USA, Earth, Solar System, Milky Way Galaxy, Virgo Supercluster
  • Liked: 1648
  • Likes Given: 4382
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #568 on: 09/01/2016 08:00 PM »
These screen shots were posted by @John_Gardi on Twitter.  Taken from this slow-mo video. ...
Seems to me that there is a bunch of software interpolation creating "detail" not in the source video.  In other words, I think it's inventing frames to smooth the transitions.

Edit:  Ninja's by RoboGoofers
« Last Edit: 09/01/2016 08:01 PM by mme »
Space is not Highlander.  There can, and will, be more than one.

Offline cscott

  • Senior Member
  • *****
  • Posts: 2949
  • Liked: 2056
  • Likes Given: 664
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #569 on: 09/01/2016 08:00 PM »

Thanks for posting the video.  Boy, watching the payload tumble to the ground/from the cradle after the fact sure adds insult to injury...
Again, my thoughts are with all involved.  Glad there weren't any injuries (any followup to reports that a firefighter was injured?)
We had a follow-up that it wasn't a medevac, the firefighter just wanted a lift to better observe the fire from above.

I certainly hope that's the case.

Offline wtrix

  • Full Member
  • *
  • Posts: 135
  • Estonia
  • Liked: 93
  • Likes Given: 10
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #570 on: 09/01/2016 08:01 PM »
Some notes:
1. There's no similarity to CRS-7 event. "Excessive venting" that some people claim here is probably mostly due to the fact that surrounding air was almost saturated with moisture. Pressure vessel overpressure rupture would have caused massive cloud initially, which then would have perhaps detonated. Not the other way around.
2. Fixing blast initiation point by analyzing video frames is not very productive as the surroundings are foggy and this fog reflects blast light towards camera making it bigger and moving the origination point towards the rocket body
« Last Edit: 09/01/2016 08:03 PM by wtrix »

Offline Dagger

  • Member
  • Posts: 19
  • Norway
  • Liked: 8
  • Likes Given: 64
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #571 on: 09/01/2016 08:06 PM »
Made a little gif. Don't know how accurate it is:




Online launchwatcher

  • Full Member
  • ***
  • Posts: 376
  • Liked: 258
  • Likes Given: 362
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #572 on: 09/01/2016 08:07 PM »
Watching this in slow motion, it appears that in the first frame with fire that there is a long downward finger of flame and smoke that dissipates as the fire ball erupts.  Is there an umbilical that could have come off and sprayed something downward?
Some of that looks to me looks like it could be light from the initial fireball illuminating preexisting vapor clouds around the top of the first stage.
« Last Edit: 09/01/2016 08:08 PM by launchwatcher »

Offline mlindner

  • Software Engineer
  • Senior Member
  • *****
  • Posts: 2090
  • Space Capitalist
  • Silicon Valley, CA -- previously in Ann Arbor, MI
  • Liked: 748
  • Likes Given: 289
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #573 on: 09/01/2016 08:15 PM »
My two cents. I might know the cause in my completely unfounded opinion. The main thing that I'm drawing my thoughts from are the intense localized flash of the explosion (as noticed by the flash star in the video film).

I believe this was a pre-detonation of the either a portion of, or completely of the upper stage FTS. There was an intense flash at a single small point. You don't get that level of intense flashes from an ignition. If this was a COPV explosion we should be seeing a spray of LOX or fuel before the explosion occurs.

I look forward to the date that rockets get their FTS removed. Having explosives on a vehicle has always seemed like a bad idea to me despite the good reasons for protection of the public they allow.
« Last Edit: 09/01/2016 08:17 PM by mlindner »
Internal combustion engine in space. It's just a Bad Idea.TM - Robotbeat

Online Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6691
  • Liked: 1000
  • Likes Given: 140
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #574 on: 09/01/2016 08:19 PM »
Where are the FTS charges located on this vehicle?  Are they running up the side like on a solid or are they on the tank domes or something?

Offline cscott

  • Senior Member
  • *****
  • Posts: 2949
  • Liked: 2056
  • Likes Given: 664
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #575 on: 09/01/2016 08:20 PM »
I believe this was a pre-detonation of the either a portion of, or completely of the upper stage FTS. There was an intense flash at a single small point. You don't get that level of intense flashes from an ignition. If this was a COPV explosion we should be seeing a spray of LOX or fuel before the explosion occurs.
FTS was safed at the time, as evidenced in the timeline by cradle closed and strongback vertical.

Still could be an anomalous FTS incident (static discharge?) but should be much much much less likely if FTS is safed.
« Last Edit: 09/01/2016 08:21 PM by cscott »

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4334
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2563
  • Likes Given: 531
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #576 on: 09/01/2016 08:21 PM »
My two cents. I might know the cause in my completely unfounded opinion. The main thing that I'm drawing my thoughts from are the intense localized flash of the explosion (as noticed by the flash star in the video film).

I believe this was a pre-detonation of the either a portion of, or completely of the upper stage FTS. There was an intense flash at a single small point. You don't get that level of intense flashes from an ignition. If this was a COPV explosion we should be seeing a spray of LOX or fuel before the explosion occurs.

I look forward to the date that rockets get their FTS removed. Having explosives on a vehicle has always seemed like a bad idea to me despite the good reasons for protection of the public they allow.

Except the FTS is, in my experience, one of the most thoroughly designed, tested, and safe systems on the rocket, precisely because Range Safety folks are so concerned about the possibility of accidental initiation. Speaking as someone who has worked with FTS systems, it's practically impossible to initiate them by mistake. So I'd be highly surprised if FTS turns out to be the culprit.

I'd much rather be standing next to an FTS than a fully pressurized COPV, for example.
« Last Edit: 09/01/2016 08:24 PM by Kabloona »

Online ellindsey

  • Member
  • Posts: 60
  • New Jersey
  • Liked: 53
  • Likes Given: 8
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #577 on: 09/01/2016 08:26 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.

Offline dnavas

  • Full Member
  • *
  • Posts: 158
  • San Jose
  • Liked: 65
  • Likes Given: 198
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #578 on: 09/01/2016 08:29 PM »
Made a little gif. Don't know how accurate it is:


It's hard to draw much from attempting to find the 2D mid-point of an over-exposure.  That said, I find it interesting how the payload fairing was illuminated.

Offline king1999

  • Full Member
  • **
  • Posts: 266
  • F-Niner Fan
  • Atlanta, GA
  • Liked: 155
  • Likes Given: 585
Re: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD
« Reply #579 on: 09/01/2016 08:31 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.

Tags: