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#2360
by
PreferToLurk
on 16 Jan, 2016 18:10
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Watching that grainy video I do get the impression that the burn was cut short of the intended duration, for a couple of reasons. Usually, when there's an abort at ignition, you can see the LOX and RP-1 tanks being immediately vented, this is what is seen here. Secondly, one would not expect the burn to end with another TEA/TEB flash. Also, chamber ignition and thrust ramp-up on M1Ds seems to start 2 seconds before T-0, the actual burn here seems to have been shorter.
Watch the video again. The stage fired for an extended period. The video ends before the firing has even completed. The second green flash (IMHO) is merely an artifact of this being filmed 5 miles away. Probably one longer flash temporarily obscured from this vantage point.
Regardless of the TEA/TEB issue, if you watch with the sound on you can clearly hear the distinctive M1D roar continue for the whole video, and of course the narrator (who can probably see better than the video camera can) clearly understands the firing to be nearly full mission duration.
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#2361
by
Kenm
on 16 Jan, 2016 18:16
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I wonder if the engine fluctuations are from RP1 in the cooling channels being fried up at the bottom of the bell. These are thin parts which can quickly heat up during reentery and the retro burns. If one of the channels was plugged the engine would probably burn out so it would have to be limited to small bits being stuck at the injector.
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#2362
by
ugordan
on 16 Jan, 2016 18:21
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Watch the video again. The stage fired for an extended period.
No, it didn't. It's obvious that the chambers were burning for just slightly under 2 seconds. It's also fairly obvious that the "rumble" sound was pasted into the video after the fact. A sample form an actual launch from the sound of it. There is a distinctive pop at 2:02 in the left audio channel that occurs when a waveform that doesn't start at 0 level is copy/pasted into another waveform so there is a discontinuity in the resulting wave. The audio sample was then pasted in *again* at 2:57. Rather dishonest, if you ask me.
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#2363
by
Oersted
on 16 Jan, 2016 18:41
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I'd be surprised if anybody tampered with that video.
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#2364
by
Lee Jay
on 16 Jan, 2016 18:49
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#2365
by
wardy89
on 16 Jan, 2016 19:03
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ok maybe i am reading into this to much but when they static fired this core before its initial launch Elon posted on twitter describing it as a static fire test.
https://twitter.com/elonmusk/status/678004229047357440"Static fire test looks good. Pending data review, will aim to launch Sunday."
Where his tweet about last night's test he described it as a hold-down firing.
https://twitter.com/elonmusk/status/688173528017850368"Conducted hold-down firing of returned Falcon rocket. Data looks good overall, but engine 9 showed thrust fluctuations."
so i guess my question is is the different way in which Elon describes the test suggestive that they did a longer burn last night or is he simply using different language to describe the usual short static fire test?
Does anyone know how long it takes for the engines to stabilise after startup? so essentially minimum amount of time the test would have to run before they knew there were thrust fluctuations in one of the engines?
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#2366
by
Dante80
on 16 Jan, 2016 19:28
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Does anyone know how long it takes for the engines to stabilise after startup? so essentially minimum amount of time the test would have to run before they knew there were thrust fluctuations in one of the engines?
From past launches, its around two seconds, isn't it?
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#2367
by
Lee Jay
on 16 Jan, 2016 19:34
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Does anyone know how long it takes for the engines to stabilise after startup? so essentially minimum amount of time the test would have to run before they knew there were thrust fluctuations in one of the engines?
From past launches, its around two seconds, isn't it?
Usually.
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#2368
by
mlindner
on 16 Jan, 2016 19:54
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Looks like it only lit for a second or so to me... ~1:50 mark in the video
It sounded like a pretty long fire to me. It takes a few second for the sound of the rocket motor firing to reach the camera's location. But at around the 2:00 mark you can start to hear the distinct rumble of the engine firing and it pretty much lasts all the way till the end of the video.
It's only as long as you can see the flame. The towers would be continue to be lit up if the flame was still going.
The video is a flat out
forgery incorrect. Why
do that? I have no idea.
Maybe he wanted additional views for revenue making for his youtube channel.
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#2369
by
somepitch
on 16 Jan, 2016 20:02
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Looks like it only lit for a second or so to me... ~1:50 mark in the video
It sounded like a pretty long fire to me. It takes a few second for the sound of the rocket motor firing to reach the camera's location. But at around the 2:00 mark you can start to hear the distinct rumble of the engine firing and it pretty much lasts all the way till the end of the video.
It's only as long as you can see the flame. The towers would be continue to be lit up if the flame was still going.
The video is a flat out forgery. Why do that? I have no idea. Maybe he wanted additional views for revenue making for his youtube channel.
Guess I wasn't seeing/hearing things after all... I admitted defeat too early!
It is really strange that someone would forge a video like that...
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#2370
by
mlindner
on 16 Jan, 2016 20:09
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I wonder if adaptive optics could be used to get an improved image. Here's a possible source.
http://www.stellarproducts.com/
Adaptive optics can only be used if you have a camera capable of bending/re-orienting its mirrors/lenses and guide point of light of known brightness and locality. It also cannot be done in post-processing. It is a live feedback effect done at the time of image taking.
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#2371
by
Dante80
on 16 Jan, 2016 20:51
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There is also clearly a continued stream of exhaust in the video. At first I thought it was foreground fog, but there are a few moments that seem to show a fast moving stream being directed somewhat away and to the right from the point of view.
This is an easy one to figure out imo. Watch some videos from static fires, and pay attention to the rate, speed and magnitude of smoke that the fire makes.
Then, go the video at hand and watch two things.
1. How fast the smoke is moving and looking around 1:44 when the stage fires.
2. How the smoke looks and behaves after 1:50 and until the end of the video.
Its looks pretty obvious to me, I might be mistaken though..
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#2372
by
saliva_sweet
on 16 Jan, 2016 20:53
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The wild accusations of tampering appear out of line for me as well. The same sounds are present throughout the video and are probably due to wind gusts and passing cars.
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#2373
by
mlindner
on 16 Jan, 2016 20:53
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Watch the video again. The stage fired for an extended period.
No, it didn't. It's obvious that the chambers were burning for just slightly under 2 seconds. It's also fairly obvious that the "rumble" sound was pasted into the video after the fact. A sample form an actual launch from the sound of it. There is a distinctive pop at 2:02 in the left audio channel that occurs when a waveform that doesn't start at 0 level is copy/pasted into another waveform so there is a discontinuity in the resulting wave. The audio sample was then pasted in *again* at 2:57. Rather dishonest, if you ask me.
Or maybe we don't attack someone's journalistic integrity over something that could easily be explained by a cheap microphone instead. The engine sounds fade in and out of the video multiple times without the " artifact" so, what, he painstakingly edited his video carefull to match all the waveforms except for that one audio channeling that one time? And for what purpose? Click Bait? Isn't a "failed static fire!!!" better click bait anyway?
There is also clearly a continued stream of exhaust in the video. At first I thought it was foreground fog, but there are a few moments that seem to show a fast moving stream being directed somewhat away and to the right from the point of view. Both the "double green" and "temporarily lit" towers could be explained by exhaust reflecting up past the water deluge in the first few moments of the firing. Remember when one of the F9's blew dirty water on itself at liftoff? Eventually everything starts flowing in the correct direction.
Personally I find it in very poor taste to question someone's integrity on a public forum without more evidence than has been provided here. That's a veteran owned 501c3 non-profit that you are accusing, FYI.
From Youtube:
Full Power 3 minutes, just under 6 total. Booster was there for two days.
He's either lying or he himself imagined the launch duration both during and after the video. He's making the claim himself that it was 6 minutes of burn. I'm accusing him of being outright wrong. Whether it is malicious or not is another question. I've edited my original comment to respect that.
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#2374
by
Dante80
on 16 Jan, 2016 20:55
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Its impossible to do a burn of 360s. The guy is not lying, he simply was too far away and misjudged what happened.
I see no malicious intent here. Just a possible misunderstanding of what he is observing.
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#2375
by
mlindner
on 16 Jan, 2016 20:57
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Its impossible to do a burn of 360s. The guy is not lying, he simply was too far away and misjudged what happened.
ugordon's audio artifacts are indeed there and very certainly sound like rocket sound effects and like no wind sound I've ever heard on a video. Maybe a non-technical editor added them later to improve the effect of what was being claimed?
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#2376
by
ugordan
on 16 Jan, 2016 21:05
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Personally I find it in very poor taste to question someone's integrity on a public forum without more evidence than has been provided here. That's a veteran owned 501c3 non-profit that you are accusing, FYI.
I really don't care if he's a veteran or not, as if that should change my conclusions about the video. I made an honest analysis of the video and am standing by my conclusion. The video is authentic, the audio is not and has been "enhanced", probably by his expectation of what the duration should have been.
For your information, since posting that analysis, two sources have confirmed what I said - that the actual duration was a couple of seconds. Ironically, one of them being an actual SpaceX engineer on another site who is being told he's the one who's wrong.
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#2377
by
Chris Bergin
on 16 Jan, 2016 21:12
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The static fire was just shy of two seconds. That is confirmed in L2 by hands on data observation. Any other suggestion is incorrect or (and I don't like people using harsh words) a misinterpretation.
Back to your regular programming.
PS We're coming to the end of this mission's coverage, but we'll keep things open until they retire the stage from testing.
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#2378
by
chalz
on 16 Jan, 2016 23:07
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Wasn't there a small fire on the stage after landing. Perhaps the engine issue is related to that.
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#2379
by
LoneHamish
on 16 Jan, 2016 23:13
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The static fire was just shy of two seconds. That is confirmed in L2 by hands on data observation. Any other suggestion is incorrect or (and I don't like people using harsh words) a misinterpretation.
Thanks for the info Chris, it's been a losing battle trying to convince people that the quoted time of "8 minutes" on some footage was wholly incorrect, regardless of the laundry list of reasons as to why it can't have happened.
