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glhs272
Unnamed plug faced villian
That could also be interpreted as a non-flight article (i.e. without engines). Perhaps one of their structural test articles that were built for qualification testing (and no longer being used) were sacrificed for these tests.
I have to say that Elon and SpaceX are awesome. They don't mess around and get right to heart of the problem. The company gets a vast amount of data from the explosion but it doesn't give any clear indication of the actual fault. There is an outside chance of sabotage and so the company hires a sharpshooter to fire a couple rounds at a mock up/test article stage to see what happens. Apparently SpaceX learned a lot from that test. Enough information to determine it is unlikely that was the cause which seems to have clarified what the real problem probably is. They also learned enough that there is a danger that needs to be addressed for future launches.
Of course it could still be the bird-like drones controlled by aliens....
Now we just have to patiently wait a couple months before we can see the next launch...
Of course it could still be the bird-like drones controlled by aliens....
Now we just have to patiently wait a couple months before we can see the next launch...
Sorry, my error in typing "first stage". I meant second stage.
@Cosmacelf, I wasn't accusing you of anything, I understood you were just passing on information.
@glhs272 what "pictures of McGregor test site" are you referring to?
@Cosmacelf, I wasn't accusing you of anything, I understood you were just passing on information.
@glhs272 what "pictures of McGregor test site" are you referring to?
Based on the reddit screen capture that @Cosmacelf posted upthread, I interpret that as saying that what SpaceX did with firing a bullet on a mockup 2nd stage demonstrated that they could replicate the explosion. I don't understand why you are saying that the test showed that scenario was "unlikely".
Elon's quote from the NRO speech said "We don’t think that is likely this time around, but we are definitely going to have to take precautions against that in the future."
So I'm just going by what Elon said.
He also said "The other thing we discovered is that we can exactly replicate what happened on the launch pad if someone shoots the rocket."
I think that means that you can blow up the rocket if you fire a bullet at it though. Which is why SpaceX will be more cautious about such a thing in the future.
hockeythug
Active Member
He is talking about L2 content from NSF which is against the rules to be posted outside of L2.
palmer_md
Member
People keep referencing the Reddit post where they quote Elon. Is there any confirmation that he actually said these things? The Reddit thread was pulled down. Was it pulled down because he didn't say it or was it pulled down because they didn't want that information getting out there.
glhs272
Unnamed plug faced villian
The pictures themselves are L2 but the discussion of the stage mock-up has been going on the Amos-6 public thread, public info so I don't think I broke any rules...
The comments were made at a classified briefing of some sort. No official record of it is likely to emerge. You either believe the veracity of the people who witnessed it or you don't. I'm not plugged in enough to the space crowd to vouch for anyone. You kinda have to follow a trust chain back to decide for yourself whether or not you believe it. For instance, there are a bunch of people on this forum that i would believe if they vouched for something, but that's based on my own interactions with them.
glhs272
Unnamed plug faced villian
SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD (2)
I am doing this from my iPhone so bear with me. Maybe start with post 743 & 773
I am doing this from my iPhone so bear with me. Maybe start with post 743 & 773
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palmer_md
Member
Thanks. As long as there are some people who believe the posters are reliable that is OK with me. I just thought I'd bring it up since it is odd that it got removed. It will be interesting to hear/read the official press release on the matter when they are done with the investigation.
SpaceX: Sept. 1 failure likely caused by breach in Falcon 9 second-stage helium tank - SpaceNews.com
tells: "from first signs of an anomaly to loss of data is about 93 milliseconds"
I'm sure they monitored He pressure, so it did not rise earlier than 93 ms before loss of data. I don't think Thermo-Acoustic Oscillations is that fast.
O2 boils at -183 C and freezes at -218 C. That's not huge difference. Thin structures cool and contracts faster than thicker parts. If tank was too warm when filled, rapid cooling might have broken something. This caused a leak.
My video editing program told that explosion video is 30 fps. Others claimed 60 fps. I figured out why: High resolution video is 60 fps. Higher resolution did not give me anything new. But extra frames did: Initial detonation was even faster. First frame with fire:
Rocket is 41 pixels wide = 3.66 m. So one pixel is 0.0893 m
Fireball is 96 pixels = 8.6 m wide and 170 high = 15.2 m
All that in 1/60 s or less. At least 1.5 * speed of sound.
Guessing volume of fireball in first frame: 9 * 9 * 15 = 1200 m^3. -> About 150 kg of explosive (RP-1 mixed with LOX) detonated.
Smoke ring has radius about 30 pixels = 2.7 m. At least 1/2 speed of sound.
Lens flare is visible in 6 frames, but not exactly in same position. So it does not give accurate point of ignition.
I found:
TechX
Exploding vertical pipe would explain shape of initial fireball and initial high speed of it. I have nothing to add...
If we trust reddit leak:
“We are close to figuring it out. It might have been formation of solid oxygen in the carbon over-wrap of one of the bottles in the upper stage tanks. If it was liquid it would have been squeezed out but under pressure it could have ignited with the carbon. This is the leading theory right now, but it is subject to confirmation."
Thermo-Acoustic Oscillations stuff, was because of another reddit rumor:
"just had dinner with a credible source i trust that spacex is about 99% sure a COPV issue was the cause. 'explosion' originated in the LOX tank COPV container that had some weird harmonics while loading LOX.
i dont have any more detailed info beyond that, just wanted to share.
the good thing is, they know the cause, that means they can come up with a solution to fix it and hopefully get back to business soon!"
“We are close to figuring it out. It might have been formation of solid oxygen in the carbon over-wrap of one of the bottles in the upper stage tanks. If it was liquid it would have been squeezed out but under pressure it could have ignited with the carbon. This is the leading theory right now, but it is subject to confirmation."
Thermo-Acoustic Oscillations stuff, was because of another reddit rumor:
"just had dinner with a credible source i trust that spacex is about 99% sure a COPV issue was the cause. 'explosion' originated in the LOX tank COPV container that had some weird harmonics while loading LOX.
i dont have any more detailed info beyond that, just wanted to share.
the good thing is, they know the cause, that means they can come up with a solution to fix it and hopefully get back to business soon!"
Does that mean that solid/frozen O2 formed inside the the carbon over-wrap material? In other words, under pressure LOX was forced into the tank wall material where it then froze solid and in solid form is capable of spontaneously igniting the carbon material?
If so, does that imply a defect in the COPV material or is it simply the nature of the material that makes such an event possible?
Is the solution then to slightly reduce the LOX temperature, reduce the pressure, both, or construct the COPV tanks differently?
No, not spontaneously. After 380 bar of He-pressure is applied to COPv.
No defect, (probably...)
SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD (2)woods170 said:
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