Author Topic: FAILURE: Shijian-18 - CZ-5 (Y2) - WSLC, LC101 - July 2, 2017 (11:23 UTC)  (Read 151570 times)

Offline Lars-J

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Watch the video at 1:03:32 on. The lower stage separates then you see engine(s) fire up and gimballing then within seconds stop firing but you can still see gimballing going on. I'm not saying there wasn't a problem with the first stage I'm saying both stages had problems.

The upper stage might have issues as well, but the first stage must contain the root cause. The upper stage does seem to shut down quickly after the first start, but that might be caused by propellant settling issues due to atmospheric friction. Later the engines do seem to start(?) - but that glow is most likely from the re-entry. (The light looks very different than the short engine start at 1:03:38)
« Last Edit: 07/03/2017 06:11 am by Lars-J »

Offline Phillip Clark

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Since stage separation reportedly did occur, the stack should have flown very far downrange. Did the third stage fire?
There is no way the 3rd stage would fire this early in the mission. Stage 2 was meant to enter parking orbit and then
reignite to GTO; stage 3 increases GTO apogee after that, with its first burn at T+31 minutes.
Have I missed something?   I thought that it was two core stages plus four strap-ons - no third stage, unless you call the strap-ons alone stage 1.
Long March 5 has an optional third stage called YZ-2, using hypergolic propellants. This had already been used in the first launch (and came in quite handy, as it could compensate for a performance shortfall of the second stage)  https://en.wikipedia.org/wiki/Long_March_5

What you say is correct, but on this launch, Y-2, the YZ-2 was not carried therefore it was a two-stage launch vehicle, as I said ..........
I've always been crazy but it's kept me from going insane - WJ.

Offline Katana

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Wouldn't there be an engine management function that would shut down the engine experiencing the problem but have the good engine continue burning longer to make up the shortfall ??...why wasn't the mission saved with a longer S1 one engine burn and a successful S2 burn ??

GNC engine management does happened already, separation delayed 100 seconds and S2 operation continued.
But T/W with S1 only one engine and T/W of S2 is not enough to save the mission.

Offline Pete

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This is unfortunate...



This is probably not related to the failure (it seems), but if you look at this video there seems to be some material dangling loose at the base of at least two boosters. It is most clearly seen around 7:07 of the video. Is that normal? And if not, is it metal pieces or some sort of insulation fabric? And could it have swung and and damaged one of the core engines?

(attached image below, but watch the video, it is more obvious there)


The flappy bit is quite normal, or at least there is an identical occurrence on the successful launch of   november last year.
See:

Offline Phillip Clark

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I know that this is academic, but do we know where Shijian 18 was planned to be located?
I've always been crazy but it's kept me from going insane - WJ.

Offline Katana

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Discussion on the event becomes fobidden on Zhihu.com, Chinese equivlent of Quora.

(System message)
Sorry, your answer is deleted with the qustion. Political sensitive content is forbidden in zhihu.  The question “How to understand CZ-5 Y2 launch failure" is deleted, your answer is deleted together.

Sorry, your answer is deleted with the qustion. According to law and requirements of goverment, your answer under The question “How to understand CZ-5 Y2 launch failure" is deleted with the question.

您好,很抱歉您的回答受到牵连。知乎不允许发布「政治敏感」内容,问题「如何看待长征五号遥二火箭发射失利?」由于违反知乎规范被删除,导致您的回答也受到牵连被删除。

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« Last Edit: 07/03/2017 01:11 pm by Katana »

Offline Ben the Space Brit

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It is easy to forget that, despite it size, increasingly cosmopolitan people and economic power, China is not a free society and, in times of great official embarrassment, will not even pretend to be.

It is obvious that this launch failure has metamorphosed into a serious political embarrassment for someone with power and we can officially expect to not hear anything else from official Chinese sources. It will be harder for the Chinese to pretend that the launch never happened as it once was. I suspect that the most we will hear after this is rumblings from anonymous CSA sources of 'foreign-funded saboteurs'.
"Oops! I left the silly thing in reverse!" - Duck Dodgers

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DON'T PROPAGANDISE, FLY!!!

Offline eeergo

Unfortunate the "old guard" still rears its head uglily in a futile exercise of showing how these situations should not be handled, both for integrity and, frankly, because it serves no purpose in today's interconnected societies, especially China's -and is actually detrimental to their assumed objective, only fueling rumors and baseless speculation in underground circles.

Hopefully they will be increasingly substituted with more open-minded personalities. Also hopefully, some recent hermetist Western attitudes won't give them a new justification to their attitude.
-DaviD-

Offline Svetoslav

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It is easy to forget that, despite it size, increasingly cosmopolitan people and economic power, China is not a free society and, in times of great official embarrassment, will not even pretend to be.

It is obvious that this launch failure has metamorphosed into a serious political embarrassment for someone with power and we can officially expect to not hear anything else from official Chinese sources. It will be harder for the Chinese to pretend that the launch never happened as it once was. I suspect that the most we will hear after this is rumblings from anonymous CSA sources of 'foreign-funded saboteurs'.

Yes, I agree that it was quite the embarrassment - especially that the launch was streamed live and people saw what went wrong in real time.

I am afraid that Chinese bureaucrats will now make the missions even less public and live streams will become even rarer.

Offline Galactic Penguin SST

I had been thinking about that strange leak on the right side - could this be the very first case of us seeing the effect of not fully combusted exhaust leaking through the nozzle into outer space (be it a case of leaky valves, burnt through pipelines or such) on rocket cam? With the launch right on the terminator, the lighting effects would enhance any particle streams around the rocket.

This might suggest a gradual leak somewhere instead of a turbopump RUD (chamber burnt through etc.) or pressurization problem I think?

What is strange is that the flow is heading towards the front - I can't think of why (exosphere atmospheric effect?).
Astronomy & spaceflight geek penguin. In a relationship w/ Space Shuttle Discovery. Current Priority: Chasing the Chinese Spaceflight Wonder Egg & A Certain Chinese Mars Rover

Offline edkyle99

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It is easy to forget that, despite it size, increasingly cosmopolitan people and economic power, China is not a free society and, in times of great official embarrassment, will not even pretend to be.

It is obvious that this launch failure has metamorphosed into a serious political embarrassment for someone with power and we can officially expect to not hear anything else from official Chinese sources. It will be harder for the Chinese to pretend that the launch never happened as it once was. I suspect that the most we will hear after this is rumblings from anonymous CSA sources of 'foreign-funded saboteurs'.

Yes, I agree that it was quite the embarrassment - especially that the launch was streamed live and people saw what went wrong in real time.

I am afraid that Chinese bureaucrats will now make the missions even less public and live streams will become even rarer.
I was impressed that this launch was broadcast live, failure or not.  If anything, this failure showed the robustness of the design, as the wounded rocket kept fighting to ascend.  I hope China's decision makers see it that way and show the world the next attempt live.

 - Ed Kyle
« Last Edit: 07/03/2017 03:49 pm by edkyle99 »

Offline input~2

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For the record, here is a navigational warning concerning nominal drop zones (boosters, fairing, 1st stage)
(source)
NAVAREA航行警報 NO.17-0427
 南シナ海北部及び北太平洋西部、ロケット打ち上げに伴う危険区域設定
 NO.17-0427    発表日時:2017年06月30日 20時
 SOUTH CHINA SEA, NORTHERN PART AND NORTH
 PACIFIC, WESTERN PART.
 ROCKET LAUNCHING. 021000Z TO 021300Z
 JUL. FOLLOWING RANGE CLEARANCE AREAS
 ESTABLISHED. AREAS BOUNDED BY
 A. 19-07.2N 119-06.1E
 19-10.5N 118-03.3E
 19-37.4N 118-04.8E
 19-34.1N 119-07.7E.
 B. 18-45.3N 124-00.2E
 18-52.2N 122-35.0E
 19-19.0N 122-37.3E
 19-12.2N 124-02.7E.
 C. 15-22.9N 144-36.9E
 15-48.7N 142-25.2E
 16-41.6N 142-36.1E
 16-15.7N 144-48.4E.
 CANCEL THIS MSG 021400Z JUL.

Offline Kryten

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Do we have a good idea where any debris would have landed?

Offline zhangmdev

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Also any information about the 2nd burn of the 2nd stage?

The velocity did not deviate the projection much, but the altitude was way off. If that altitude curve was accurate, the 2nd stage was dipping towards 100 km. It could be reentering before the 2nd burn. That was quite unexpected. One of the core engine lost thrust fairly late into the 1st stage burn, and the remaining engine burned additional 100+ seconds to make up the shortfall. The payload mass was about half of the projected GTO capacity, there should be quite a large margin. So why wouldn't the 2nd stage burn for extra longer time and ended up in the LEO at least?


Offline Lars-J

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What is strange is that the flow is heading towards the front - I can't think of why (exosphere atmospheric effect?).

Recirculating of exhaust at high altitude. Happens on all launch vehicles, there are some good Saturn V images where it almost reaches the top of the first stage.
« Last Edit: 07/03/2017 06:29 pm by Lars-J »

Offline AnnK

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I wonder if the second stage and its payload impacted somewhere east of Manlia in the PI?
Ad Astra per Aspera

Offline Lars-J

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I wonder if the second stage and its payload impacted somewhere east of Manlia in the PI?

No, its trajectory was north of the Philippines, it would have to have been way off course.
« Last Edit: 07/03/2017 06:29 pm by Lars-J »

Offline Lars-J

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Discussion on the event becomes fobidden on Zhihu.com, Chinese equivlent of Quora.

(System message)
Sorry, your answer is deleted with the qustion. Political sensitive content is forbidden in zhihu.  The question “How to understand CZ-5 Y2 launch failure" is deleted, your answer is deleted together.

Sorry, your answer is deleted with the qustion. According to law and requirements of goverment, your answer under The question “How to understand CZ-5 Y2 launch failure" is deleted with the question.

您好,很抱歉您的回答受到牵连。知乎不允许发布「政治敏感」内容,问题「如何看待长征五号遥二火箭发射失利?」由于违反知乎规范被删除,导致您的回答也受到牵连被删除。

您好,根据法律法规和有关部门通知,您在问题「如何看待长征五号遥二火箭发射失利?」下的回答被牵连删除,还请您谅解。

The incident is still openly discussed on other Chinese forums. So this may be a more of a Zhihu policy.
« Last Edit: 07/03/2017 06:21 pm by Lars-J »

Offline Lars-J

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Watch the video at 1:03:32 on. The lower stage separates then you see engine(s) fire up and gimballing then within seconds stop firing but you can still see gimballing going on. I'm not saying there wasn't a problem with the first stage I'm saying both stages had problems.

The upper stage might have issues as well, but the first stage must contain the root cause. The upper stage does seem to shut down quickly after the first start, but that might be caused by propellant settling issues due to atmospheric friction. Later the engines do seem to start(?) - but that glow is most likely from the re-entry. (The light looks very different than the short engine start at 1:03:38)

After reviewing the first CZ-5 launch, I'll have to change my mind. It looks like the upper stage does start and may actually continue running. The upper stage engines produce very little light, and the initial short light is only the startup and perhaps a combination with settling thrusters.

Offline AnnK

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I wonder if the second stage and its payload impacted somewhere east of Manlia in the PI?

No, its trajectory was north of the Philippines, it would have to have been way off course.

Then how about this video?

As for the Chinese booster being off course, the first stage appears to lose an engine and the second stage did not properly operate. After watching this and another video, wonder if it impacted within the Philipines?
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